1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 uschar * smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Recheck synchronization *
324 *************************************************/
326 /* Synchronization checks can never be perfect because a packet may be on its
327 way but not arrived when the check is done. Normally, the checks happen when
328 commands are read: Exim ensures that there is no more input in the input buffer.
329 In normal cases, the response to the command will be fast, and there is no
332 However, for some commands an ACL is run, and that can include delays. In those
333 cases, it is useful to do another check on the input just before sending the
334 response. This also applies at the start of a connection. This function does
335 that check by means of the select() function, as long as the facility is not
336 disabled or inappropriate. A failure of select() is ignored.
338 When there is unwanted input, we read it so that it appears in the log of the
342 Returns: TRUE if all is well; FALSE if there is input pending
346 wouldblock_reading(void)
350 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
353 if (tls_in.active.sock >= 0)
354 return !tls_could_read();
357 if (smtp_inptr < smtp_inend)
360 fd = fileno(smtp_in);
363 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
365 if (rc <= 0) return TRUE; /* Not ready to read */
366 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
367 if (rc < 0) return TRUE; /* End of file or error */
376 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
379 return wouldblock_reading();
383 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
384 a reponse with the one following. */
387 pipeline_response(void)
389 if ( !smtp_enforce_sync || !sender_host_address
390 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
393 if (wouldblock_reading()) return FALSE;
394 f.smtp_in_pipelining_used = TRUE;
399 #ifndef DISABLE_PIPE_CONNECT
401 pipeline_connect_sends(void)
403 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
406 if (wouldblock_reading()) return FALSE;
407 f.smtp_in_early_pipe_used = TRUE;
412 /*************************************************
413 * Log incomplete transactions *
414 *************************************************/
416 /* This function is called after a transaction has been aborted by RSET, QUIT,
417 connection drops or other errors. It logs the envelope information received
418 so far in order to preserve address verification attempts.
420 Argument: string to indicate what aborted the transaction
425 incomplete_transaction_log(uschar *what)
427 if (!sender_address /* No transaction in progress */
428 || !LOGGING(smtp_incomplete_transaction))
431 /* Build list of recipients for logging */
433 if (recipients_count > 0)
435 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
436 for (int i = 0; i < recipients_count; i++)
437 raw_recipients[i] = recipients_list[i].address;
438 raw_recipients_count = recipients_count;
441 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
442 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
449 smtp_command_timeout_exit(void)
451 log_write(L_lost_incoming_connection,
452 LOG_MAIN, "SMTP command timeout on%s connection from %s",
453 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
454 if (smtp_batched_input)
455 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
456 smtp_notquit_exit(US"command-timeout", US"421",
457 US"%s: SMTP command timeout - closing connection",
458 smtp_active_hostname);
459 exim_exit(EXIT_FAILURE);
463 smtp_command_sigterm_exit(void)
465 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
466 if (smtp_batched_input)
467 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
468 smtp_notquit_exit(US"signal-exit", US"421",
469 US"%s: Service not available - closing connection", smtp_active_hostname);
470 exim_exit(EXIT_FAILURE);
474 smtp_data_timeout_exit(void)
476 log_write(L_lost_incoming_connection,
477 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
478 sender_fullhost ? sender_fullhost : US"local process", sender_address);
479 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
480 /* Does not return */
484 smtp_data_sigint_exit(void)
486 log_write(0, LOG_MAIN, "%s closed after %s",
487 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
488 receive_bomb_out(US"signal-exit",
489 US"Service not available - SIGTERM or SIGINT received");
490 /* Does not return */
495 /* Refill the buffer, and notify DKIM verification code.
496 Return false for error or EOF.
500 smtp_refill(unsigned lim)
503 if (!smtp_out) return FALSE;
505 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
507 /* Limit amount read, so non-message data is not fed to DKIM.
508 Take care to not touch the safety NUL at the end of the buffer. */
510 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
512 if (smtp_receive_timeout > 0) ALARM_CLR(0);
515 /* Must put the error text in fixed store, because this might be during
516 header reading, where it releases unused store above the header. */
519 if (had_command_timeout) /* set by signal handler */
520 smtp_command_timeout_exit(); /* does not return */
521 if (had_command_sigterm)
522 smtp_command_sigterm_exit();
523 if (had_data_timeout)
524 smtp_data_timeout_exit();
526 smtp_data_sigint_exit();
528 smtp_had_error = save_errno;
529 smtp_read_error = string_copy_perm(
530 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
537 dkim_exim_verify_feed(smtp_inbuffer, rc);
539 smtp_inend = smtp_inbuffer + rc;
540 smtp_inptr = smtp_inbuffer;
544 /*************************************************
545 * SMTP version of getc() *
546 *************************************************/
548 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
549 it flushes the output, and refills the buffer, with a timeout. The signal
550 handler is set appropriately by the calling function. This function is not used
551 after a connection has negotiated itself into an TLS/SSL state.
553 Arguments: lim Maximum amount to read/buffer
554 Returns: the next character or EOF
558 smtp_getc(unsigned lim)
560 if (smtp_inptr >= smtp_inend)
561 if (!smtp_refill(lim))
563 return *smtp_inptr++;
567 smtp_getbuf(unsigned * len)
572 if (smtp_inptr >= smtp_inend)
573 if (!smtp_refill(*len))
574 { *len = 0; return NULL; }
576 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
587 int n = smtp_inend - smtp_inptr;
588 if (chunking_state == CHUNKING_LAST && chunking_data_left < n)
589 n = chunking_data_left;
591 dkim_exim_verify_feed(smtp_inptr, n);
596 /* Forward declarations */
597 static inline void bdat_push_receive_functions(void);
598 static inline void bdat_pop_receive_functions(void);
601 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
602 previous BDAT chunk and getting new ones when we run out. Uses the
603 underlying smtp_getc or tls_getc both for that and for getting the
604 (buffered) data byte. EOD signals (an expected) no further data.
605 ERR signals a protocol error, and EOF a closed input stream.
607 Called from read_bdat_smtp() in receive.c for the message body, but also
608 by the headers read loop in receive_msg(); manipulates chunking_state
609 to handle the BDAT command/response.
610 Placed here due to the correlation with the above smtp_getc(), which it wraps,
611 and also by the need to do smtp command/response handling.
613 Arguments: lim (ignored)
614 Returns: the next character or ERR, EOD or EOF
618 bdat_getc(unsigned lim)
620 uschar * user_msg = NULL;
629 if (chunking_data_left > 0)
630 return lwr_receive_getc(chunking_data_left--);
632 bdat_pop_receive_functions();
634 dkim_save = dkim_collect_input;
635 dkim_collect_input = 0;
638 /* Unless PIPELINING was offered, there should be no next command
639 until after we ack that chunk */
641 if (!f.smtp_in_pipelining_advertised && !check_sync())
643 unsigned n = smtp_inend - smtp_inptr;
646 incomplete_transaction_log(US"sync failure");
647 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
648 "(next input sent too soon: pipelining was not advertised): "
649 "rejected \"%s\" %s next input=\"%s\"%s",
650 smtp_cmd_buffer, host_and_ident(TRUE),
651 string_printing(string_copyn(smtp_inptr, n)),
652 smtp_inend - smtp_inptr > n ? "..." : "");
653 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
654 US"SMTP synchronization error");
655 goto repeat_until_rset;
658 /* If not the last, ack the received chunk. The last response is delayed
659 until after the data ACL decides on it */
661 if (chunking_state == CHUNKING_LAST)
664 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
669 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
670 chunking_state = CHUNKING_OFFERED;
671 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
673 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
674 QUIT, RSET or NOOP but handling them seems obvious */
677 switch(smtp_read_command(TRUE, 1))
680 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
681 US"only BDAT permissible after non-LAST BDAT");
684 switch(smtp_read_command(TRUE, 1))
686 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
687 case EOF_CMD: return EOF;
688 case RSET_CMD: smtp_rset_handler(); return ERR;
689 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
690 US"only RSET accepted now") > 0)
692 goto repeat_until_rset;
696 smtp_quit_handler(&user_msg, &log_msg);
707 smtp_printf("250 OK\r\n", FALSE);
714 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
716 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
717 US"missing size for BDAT command");
720 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
721 ? CHUNKING_LAST : CHUNKING_ACTIVE;
722 chunking_data_left = chunking_datasize;
723 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
724 (int)chunking_state, chunking_data_left);
726 if (chunking_datasize == 0)
727 if (chunking_state == CHUNKING_LAST)
731 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
732 US"zero size for BDAT command");
733 goto repeat_until_rset;
736 bdat_push_receive_functions();
738 dkim_collect_input = dkim_save;
740 break; /* to top of main loop */
747 bdat_getbuf(unsigned * len)
751 if (chunking_data_left <= 0)
752 { *len = 0; return NULL; }
754 if (*len > chunking_data_left) *len = chunking_data_left;
755 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
756 chunking_data_left -= *len;
761 bdat_flush_data(void)
763 while (chunking_data_left)
765 unsigned n = chunking_data_left;
766 if (!bdat_getbuf(&n)) break;
769 bdat_pop_receive_functions();
771 if (chunking_state != CHUNKING_LAST)
773 chunking_state = CHUNKING_OFFERED;
774 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
780 bdat_push_receive_functions(void)
782 /* push the current receive_* function on the "stack", and
783 replace them by bdat_getc(), which in turn will use the lwr_receive_*
784 functions to do the dirty work. */
785 if (lwr_receive_getc == NULL)
787 lwr_receive_getc = receive_getc;
788 lwr_receive_getbuf = receive_getbuf;
789 lwr_receive_ungetc = receive_ungetc;
793 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
796 receive_getc = bdat_getc;
797 receive_getbuf = bdat_getbuf;
798 receive_ungetc = bdat_ungetc;
802 bdat_pop_receive_functions(void)
804 if (lwr_receive_getc == NULL)
806 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
809 receive_getc = lwr_receive_getc;
810 receive_getbuf = lwr_receive_getbuf;
811 receive_ungetc = lwr_receive_ungetc;
813 lwr_receive_getc = NULL;
814 lwr_receive_getbuf = NULL;
815 lwr_receive_ungetc = NULL;
818 /*************************************************
819 * SMTP version of ungetc() *
820 *************************************************/
822 /* Puts a character back in the input buffer. Only ever
828 Returns: the character
842 chunking_data_left++;
843 return lwr_receive_ungetc(ch);
848 /*************************************************
849 * SMTP version of feof() *
850 *************************************************/
852 /* Tests for a previous EOF
855 Returns: non-zero if the eof flag is set
867 /*************************************************
868 * SMTP version of ferror() *
869 *************************************************/
871 /* Tests for a previous read error, and returns with errno
872 restored to what it was when the error was detected.
875 Returns: non-zero if the error flag is set
881 errno = smtp_had_error;
882 return smtp_had_error;
887 /*************************************************
888 * Test for characters in the SMTP buffer *
889 *************************************************/
891 /* Used at the end of a message
900 return smtp_inptr < smtp_inend;
905 /*************************************************
906 * Write formatted string to SMTP channel *
907 *************************************************/
909 /* This is a separate function so that we don't have to repeat everything for
910 TLS support or debugging. It is global so that the daemon and the
911 authentication functions can use it. It does not return any error indication,
912 because major problems such as dropped connections won't show up till an output
913 flush for non-TLS connections. The smtp_fflush() function is available for
914 checking that: for convenience, TLS output errors are remembered here so that
915 they are also picked up later by smtp_fflush().
917 This function is exposed to the local_scan API; do not change the signature.
921 more further data expected
922 ... optional arguments
928 smtp_printf(const char *format, BOOL more, ...)
933 smtp_vprintf(format, more, ap);
937 /* This is split off so that verify.c:respond_printf() can, in effect, call
938 smtp_printf(), bearing in mind that in C a vararg function can't directly
939 call another vararg function, only a function which accepts a va_list.
941 This function is exposed to the local_scan API; do not change the signature.
943 /*XXX consider passing caller-info in, for string_vformat-onward */
946 smtp_vprintf(const char *format, BOOL more, va_list ap)
948 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
951 /* Use taint-unchecked routines for writing into big_buffer, trusting
952 that we'll never expand it. */
954 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
955 string_from_gstring(&gs);
959 uschar *msg_copy, *cr, *end;
960 msg_copy = string_copy(gs.s);
961 end = msg_copy + gs.ptr;
962 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
963 memmove(cr, cr + 1, (end--) - cr);
964 debug_printf("SMTP>> %s", msg_copy);
969 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
970 smtp_closedown(US"Unexpected error");
971 exim_exit(EXIT_FAILURE);
974 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
975 have had the same. Note: this code is also present in smtp_respond(). It would
976 be tidier to have it only in one place, but when it was added, it was easier to
977 do it that way, so as not to have to mess with the code for the RCPT command,
978 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
980 if (fl.rcpt_in_progress)
982 if (rcpt_smtp_response == NULL)
983 rcpt_smtp_response = string_copy(big_buffer);
984 else if (fl.rcpt_smtp_response_same &&
985 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
986 fl.rcpt_smtp_response_same = FALSE;
987 fl.rcpt_in_progress = FALSE;
990 /* Now write the string */
994 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
996 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
998 smtp_write_error = -1;
1003 /*************************************************
1004 * Flush SMTP out and check for error *
1005 *************************************************/
1007 /* This function isn't currently used within Exim (it detects errors when it
1008 tries to read the next SMTP input), but is available for use in local_scan().
1009 It flushes the output and checks for errors.
1012 Returns: 0 for no error; -1 after an error
1018 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1022 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1024 (fflush(smtp_out) != 0)
1026 smtp_write_error = -1;
1028 return smtp_write_error;
1033 /*************************************************
1034 * SMTP command read timeout *
1035 *************************************************/
1037 /* Signal handler for timing out incoming SMTP commands. This attempts to
1040 Argument: signal number (SIGALRM)
1045 command_timeout_handler(int sig)
1047 had_command_timeout = sig;
1052 /*************************************************
1053 * SIGTERM received *
1054 *************************************************/
1056 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1058 Argument: signal number (SIGTERM)
1063 command_sigterm_handler(int sig)
1065 had_command_sigterm = sig;
1071 #ifdef SUPPORT_PROXY
1072 /*************************************************
1073 * Check if host is required proxy host *
1074 *************************************************/
1075 /* The function determines if inbound host will be a regular smtp host
1076 or if it is configured that it must use Proxy Protocol. A local
1084 check_proxy_protocol_host()
1088 if ( sender_host_address
1089 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1090 sender_host_address, NULL)) == OK)
1093 debug_printf("Detected proxy protocol configured host\n");
1094 proxy_session = TRUE;
1096 return proxy_session;
1100 /*************************************************
1101 * Read data until newline or end of buffer *
1102 *************************************************/
1103 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1104 read an entire buffer and assume there will be nothing past a proxy protocol
1105 header. Our approach normally is to use stdio, but again that relies upon
1106 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1107 reading _nothing_ before client TLS handshake. So we don't want to use the
1108 usual buffering reads which may read enough to block TLS starting.
1110 So unfortunately we're down to "read one byte at a time, with a syscall each,
1111 and expect a little overhead", for all proxy-opened connections which are v1,
1112 just to handle the TLS-on-connect case. Since SSL functions wrap the
1113 underlying fd, we can't assume that we can feed them any already-read content.
1115 We need to know where to read to, the max capacity, and we'll read until we
1116 get a CR and one more character. Let the caller scream if it's CR+!LF.
1118 Return the amount read.
1122 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1124 uschar *to = base + already;
1130 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1131 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1133 cr = memchr(base, '\r', already);
1136 if ((cr - base) < already - 1)
1138 /* \r and presumed \n already within what we have; probably not
1139 actually proxy protocol, but abort cleanly. */
1142 /* \r is last character read, just need one more. */
1146 while (capacity > 0)
1148 do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
1160 /* reached end without having room for a final newline, abort */
1165 /*************************************************
1166 * Setup host for proxy protocol *
1167 *************************************************/
1168 /* The function configures the connection based on a header from the
1169 inbound host to use Proxy Protocol. The specification is very exact
1170 so exit with an error if do not find the exact required pieces. This
1171 includes an incorrect number of spaces separating args.
1174 Returns: Boolean success
1178 setup_proxy_protocol_host()
1190 struct { /* TCP/UDP over IPv4, len = 12 */
1196 struct { /* TCP/UDP over IPv6, len = 36 */
1197 uint8_t src_addr[16];
1198 uint8_t dst_addr[16];
1202 struct { /* AF_UNIX sockets, len = 216 */
1203 uschar src_addr[108];
1204 uschar dst_addr[108];
1210 /* Temp variables used in PPv2 address:port parsing */
1212 char tmpip[INET_ADDRSTRLEN];
1213 struct sockaddr_in tmpaddr;
1214 char tmpip6[INET6_ADDRSTRLEN];
1215 struct sockaddr_in6 tmpaddr6;
1217 /* We can't read "all data until end" because while SMTP is
1218 server-speaks-first, the TLS handshake is client-speaks-first, so for
1219 TLS-on-connect ports the proxy protocol header will usually be immediately
1220 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1221 reinject data for reading by those. So instead we first read "enough to be
1222 safely read within the header, and figure out how much more to read".
1223 For v1 we will later read to the end-of-line, for v2 we will read based upon
1226 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1227 data is needed total. For v1, where the line looks like:
1228 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1230 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1231 We seem to support that. So, if we read 14 octets then we can tell if we're
1232 v2 or v1. If we're v1, we can continue reading as normal.
1234 If we're v2, we can't slurp up the entire header. We need the length in the
1235 15th & 16th octets, then to read everything after that.
1237 So to safely handle v1 and v2, with client-sent-first supported correctly,
1238 we have to do a minimum of 3 read calls, not 1. Eww.
1241 #define PROXY_INITIAL_READ 14
1242 #define PROXY_V2_HEADER_SIZE 16
1243 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1244 # error Code bug in sizes of data to read for proxy usage
1249 int fd = fileno(smtp_in);
1250 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1251 uschar * iptype; /* To display debug info */
1252 socklen_t vslen = sizeof(struct timeval);
1255 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1256 ALARM(proxy_protocol_timeout);
1260 /* The inbound host was declared to be a Proxy Protocol host, so
1261 don't do a PEEK into the data, actually slurp up enough to be
1262 "safe". Can't take it all because TLS-on-connect clients follow
1263 immediately with TLS handshake. */
1264 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1266 while (ret == -1 && errno == EINTR && !had_command_timeout);
1271 /* For v2, handle reading the length, and then the rest. */
1272 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1277 /* First get the length fields. */
1280 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1281 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1286 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1288 /* May 2014: haproxy combined the version and command into one byte to
1289 allow two full bytes for the length field in order to proxy SSL
1290 connections. SSL Proxy is not supported in this version of Exim, but
1291 must still separate values here. */
1295 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1299 /* The v2 header will always be 16 bytes per the spec. */
1300 size = 16 + ntohs(hdr.v2.len);
1301 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1302 size, (int)sizeof(hdr));
1304 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1305 amount that we need. Double-check that the size is not unreasonable, then
1307 if (size > sizeof(hdr))
1309 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1317 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1318 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1322 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1323 } while (ret < size);
1325 } /* end scope for getting rest of data for v2 */
1327 /* At this point: if PROXYv2, we've read the exact size required for all data;
1328 if PROXYv1 then we've read "less than required for any valid line" and should
1331 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1333 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1337 case 0x01: /* PROXY command */
1340 case 0x11: /* TCPv4 address type */
1342 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1343 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1344 if (!string_is_ip_address(US tmpip, NULL))
1346 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1349 proxy_local_address = sender_host_address;
1350 sender_host_address = string_copy(US tmpip);
1351 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1352 proxy_local_port = sender_host_port;
1353 sender_host_port = tmpport;
1354 /* Save dest ip/port */
1355 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1356 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1357 if (!string_is_ip_address(US tmpip, NULL))
1359 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1362 proxy_external_address = string_copy(US tmpip);
1363 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1364 proxy_external_port = tmpport;
1366 case 0x21: /* TCPv6 address type */
1368 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1369 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1370 if (!string_is_ip_address(US tmpip6, NULL))
1372 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1375 proxy_local_address = sender_host_address;
1376 sender_host_address = string_copy(US tmpip6);
1377 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1378 proxy_local_port = sender_host_port;
1379 sender_host_port = tmpport;
1380 /* Save dest ip/port */
1381 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1382 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1383 if (!string_is_ip_address(US tmpip6, NULL))
1385 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1388 proxy_external_address = string_copy(US tmpip6);
1389 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1390 proxy_external_port = tmpport;
1394 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1398 /* Unsupported protocol, keep local connection address */
1400 case 0x00: /* LOCAL command */
1401 /* Keep local connection address for LOCAL */
1406 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1410 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1414 uschar *sp; /* Utility variables follow */
1419 /* get the rest of the line */
1420 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1425 p = string_copy(hdr.v1.line);
1426 end = memchr(p, '\r', ret - 1);
1428 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1430 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1433 *end = '\0'; /* Terminate the string */
1434 size = end + 2 - p; /* Skip header + CRLF */
1435 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1436 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1437 /* Step through the string looking for the required fields. Ensure
1438 strict adherence to required formatting, exit for any error. */
1440 if (!isspace(*(p++)))
1442 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1445 if (!Ustrncmp(p, CCS"TCP4", 4))
1447 else if (!Ustrncmp(p,CCS"TCP6", 4))
1449 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1451 iptype = US"Unknown";
1456 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1460 p += Ustrlen(iptype);
1461 if (!isspace(*(p++)))
1463 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1466 /* Find the end of the arg */
1467 if ((sp = Ustrchr(p, ' ')) == NULL)
1470 debug_printf("Did not find proxied src %s\n", iptype);
1474 if(!string_is_ip_address(p, NULL))
1477 debug_printf("Proxied src arg is not an %s address\n", iptype);
1480 proxy_local_address = sender_host_address;
1481 sender_host_address = p;
1483 if ((sp = Ustrchr(p, ' ')) == NULL)
1486 debug_printf("Did not find proxy dest %s\n", iptype);
1490 if(!string_is_ip_address(p, NULL))
1493 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1496 proxy_external_address = p;
1498 if ((sp = Ustrchr(p, ' ')) == NULL)
1500 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1504 tmp_port = strtol(CCS p, &endc, 10);
1505 if (*endc || tmp_port == 0)
1508 debug_printf("Proxied src port '%s' not an integer\n", p);
1511 proxy_local_port = sender_host_port;
1512 sender_host_port = tmp_port;
1514 if ((sp = Ustrchr(p, '\0')) == NULL)
1516 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1519 tmp_port = strtol(CCS p, &endc, 10);
1520 if (*endc || tmp_port == 0)
1523 debug_printf("Proxy dest port '%s' not an integer\n", p);
1526 proxy_external_port = tmp_port;
1527 /* Already checked for /r /n above. Good V1 header received. */
1531 /* Wrong protocol */
1532 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1533 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1539 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1540 yield = proxy_session;
1542 /* Don't flush any potential buffer contents. Any input on proxyfail
1543 should cause a synchronization failure */
1546 DEBUG(D_receive) if (had_command_timeout)
1547 debug_printf("Timeout while reading proxy header\n");
1552 sender_host_name = NULL;
1553 (void) host_name_lookup();
1554 host_build_sender_fullhost();
1558 f.proxy_session_failed = TRUE;
1560 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1568 /*************************************************
1569 * Read one command line *
1570 *************************************************/
1572 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1573 There are sites that don't do this, and in any case internal SMTP probably
1574 should check only for LF. Consequently, we check here for LF only. The line
1575 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1576 an unknown command. The command is read into the global smtp_cmd_buffer so that
1577 it is available via $smtp_command.
1579 The character reading routine sets up a timeout for each block actually read
1580 from the input (which may contain more than one command). We set up a special
1581 signal handler that closes down the session on a timeout. Control does not
1582 return when it runs.
1585 check_sync if TRUE, check synchronization rules if global option is TRUE
1586 buffer_lim maximum to buffer in lower layer
1588 Returns: a code identifying the command (enumerated above)
1592 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1596 BOOL hadnull = FALSE;
1598 had_command_timeout = 0;
1599 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1601 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1603 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1605 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1613 smtp_cmd_buffer[ptr++] = c;
1616 receive_linecount++; /* For BSMTP errors */
1617 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1619 /* If hit end of file, return pseudo EOF command. Whether we have a
1620 part-line already read doesn't matter, since this is an error state. */
1622 if (c == EOF) return EOF_CMD;
1624 /* Remove any CR and white space at the end of the line, and terminate the
1627 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1628 smtp_cmd_buffer[ptr] = 0;
1630 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1632 /* NULLs are not allowed in SMTP commands */
1634 if (hadnull) return BADCHAR_CMD;
1636 /* Scan command list and return identity, having set the data pointer
1637 to the start of the actual data characters. Check for SMTP synchronization
1640 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1642 #ifdef SUPPORT_PROXY
1643 /* Only allow QUIT command if Proxy Protocol parsing failed */
1644 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1648 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1649 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1650 || smtp_cmd_buffer[p->len] == 0
1651 || smtp_cmd_buffer[p->len] == ' '
1654 if (smtp_inptr < smtp_inend && /* Outstanding input */
1655 p->cmd < sync_cmd_limit && /* Command should sync */
1656 check_sync && /* Local flag set */
1657 smtp_enforce_sync && /* Global flag set */
1658 sender_host_address != NULL && /* Not local input */
1659 !f.sender_host_notsocket) /* Really is a socket */
1662 /* The variables $smtp_command and $smtp_command_argument point into the
1663 unmodified input buffer. A copy of the latter is taken for actual
1664 processing, so that it can be chopped up into separate parts if necessary,
1665 for example, when processing a MAIL command options such as SIZE that can
1666 follow the sender address. */
1668 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1669 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1670 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1671 smtp_cmd_data = smtp_data_buffer;
1673 /* Count non-mail commands from those hosts that are controlled in this
1674 way. The default is all hosts. We don't waste effort checking the list
1675 until we get a non-mail command, but then cache the result to save checking
1676 again. If there's a DEFER while checking the host, assume it's in the list.
1678 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1679 start of each incoming message by fiddling with the value in the table. */
1681 if (!p->is_mail_cmd)
1683 if (count_nonmail == TRUE_UNSET) count_nonmail =
1684 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1685 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1686 return TOO_MANY_NONMAIL_CMD;
1689 /* If there is data for a command that does not expect it, generate the
1692 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1696 #ifdef SUPPORT_PROXY
1697 /* Only allow QUIT command if Proxy Protocol parsing failed */
1698 if (proxy_session && f.proxy_session_failed)
1699 return PROXY_FAIL_IGNORE_CMD;
1702 /* Enforce synchronization for unknown commands */
1704 if ( smtp_inptr < smtp_inend /* Outstanding input */
1705 && check_sync /* Local flag set */
1706 && smtp_enforce_sync /* Global flag set */
1707 && sender_host_address /* Not local input */
1708 && !f.sender_host_notsocket) /* Really is a socket */
1716 /*************************************************
1717 * Forced closedown of call *
1718 *************************************************/
1720 /* This function is called from log.c when Exim is dying because of a serious
1721 disaster, and also from some other places. If an incoming non-batched SMTP
1722 channel is open, it swallows the rest of the incoming message if in the DATA
1723 phase, sends the reply string, and gives an error to all subsequent commands
1724 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1728 message SMTP reply string to send, excluding the code
1734 smtp_closedown(uschar *message)
1736 if (!smtp_in || smtp_batched_input) return;
1737 receive_swallow_smtp();
1738 smtp_printf("421 %s\r\n", FALSE, message);
1740 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1746 f.smtp_in_quit = TRUE;
1747 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1752 smtp_printf("250 Reset OK\r\n", FALSE);
1756 smtp_printf("421 %s\r\n", FALSE, message);
1764 /*************************************************
1765 * Set up connection info for logging *
1766 *************************************************/
1768 /* This function is called when logging information about an SMTP connection.
1769 It sets up appropriate source information, depending on the type of connection.
1770 If sender_fullhost is NULL, we are at a very early stage of the connection;
1771 just use the IP address.
1774 Returns: a string describing the connection
1778 smtp_get_connection_info(void)
1780 const uschar * hostname = sender_fullhost
1781 ? sender_fullhost : sender_host_address;
1784 return string_sprintf("SMTP connection from %s", hostname);
1786 if (f.sender_host_unknown || f.sender_host_notsocket)
1787 return string_sprintf("SMTP connection from %s", sender_ident);
1790 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1792 if (LOGGING(incoming_interface) && interface_address)
1793 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1794 interface_address, interface_port);
1796 return string_sprintf("SMTP connection from %s", hostname);
1802 /* Append TLS-related information to a log line
1805 g String under construction: allocated string to extend, or NULL
1807 Returns: Allocated string or NULL
1810 s_tlslog(gstring * g)
1812 if (LOGGING(tls_cipher) && tls_in.cipher)
1814 g = string_append(g, 2, US" X=", tls_in.cipher);
1815 #ifndef DISABLE_TLS_RESUME
1816 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1817 g = string_catn(g, US"*", 1);
1820 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1821 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1822 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1823 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1824 if (LOGGING(tls_sni) && tls_in.sni)
1825 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1833 s_connhad_log(gstring * g)
1835 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1836 ? US" C=..." : US" C=";
1838 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1839 if (smtp_connection_had[i] != SCH_NONE)
1841 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1844 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1845 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1850 /*************************************************
1851 * Log lack of MAIL if so configured *
1852 *************************************************/
1854 /* This function is called when an SMTP session ends. If the log selector
1855 smtp_no_mail is set, write a log line giving some details of what has happened
1856 in the SMTP session.
1863 smtp_log_no_mail(void)
1868 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1871 if (sender_host_authenticated)
1873 g = string_append(g, 2, US" A=", sender_host_authenticated);
1874 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1881 g = s_connhad_log(g);
1883 if (!(s = string_from_gstring(g))) s = US"";
1885 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1886 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1887 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1891 /* Return list of recent smtp commands */
1896 gstring * list = NULL;
1899 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1900 if (smtp_connection_had[i] != SCH_NONE)
1901 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1903 for (int i = 0; i < smtp_ch_index; i++)
1904 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1906 s = string_from_gstring(list);
1907 return s ? s : US"";
1913 /*************************************************
1914 * Check HELO line and set sender_helo_name *
1915 *************************************************/
1917 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1918 the domain name of the sending host, or an ip literal in square brackets. The
1919 argument is placed in sender_helo_name, which is in malloc store, because it
1920 must persist over multiple incoming messages. If helo_accept_junk is set, this
1921 host is permitted to send any old junk (needed for some broken hosts).
1922 Otherwise, helo_allow_chars can be used for rogue characters in general
1923 (typically people want to let in underscores).
1926 s the data portion of the line (already past any white space)
1928 Returns: TRUE or FALSE
1932 check_helo(uschar *s)
1935 uschar *end = s + Ustrlen(s);
1936 BOOL yield = fl.helo_accept_junk;
1938 /* Discard any previous helo name */
1940 sender_helo_name = NULL;
1942 /* Skip tests if junk is permitted. */
1946 /* Allow the new standard form for IPv6 address literals, namely,
1947 [IPv6:....], and because someone is bound to use it, allow an equivalent
1948 IPv4 form. Allow plain addresses as well. */
1955 if (strncmpic(s, US"[IPv6:", 6) == 0)
1956 yield = (string_is_ip_address(s+6, NULL) == 6);
1957 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1958 yield = (string_is_ip_address(s+6, NULL) == 4);
1960 yield = (string_is_ip_address(s+1, NULL) != 0);
1965 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1966 that have been configured (usually underscore - sigh). */
1969 for (yield = TRUE; *s; s++)
1970 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1971 Ustrchr(helo_allow_chars, *s) == NULL)
1977 /* Save argument if OK */
1979 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1987 /*************************************************
1988 * Extract SMTP command option *
1989 *************************************************/
1991 /* This function picks the next option setting off the end of smtp_cmd_data. It
1992 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1993 things that can appear there.
1996 name point this at the name
1997 value point this at the data string
1999 Returns: TRUE if found an option
2003 extract_option(uschar **name, uschar **value)
2006 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2007 while (isspace(*v)) v--;
2009 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2011 /* Take care to not stop at a space embedded in a quoted local-part */
2013 if ((*v == '"') && (v > smtp_cmd_data + 1))
2014 do v--; while (*v != '"' && v > smtp_cmd_data+1);
2021 while(isalpha(n[-1])) n--;
2022 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2023 if (!isspace(n[-1])) return FALSE;
2029 if (v == smtp_cmd_data) return FALSE;
2041 /*************************************************
2042 * Reset for new message *
2043 *************************************************/
2045 /* This function is called whenever the SMTP session is reset from
2046 within either of the setup functions; also from the daemon loop.
2048 Argument: the stacking pool storage reset point
2053 smtp_reset(void *reset_point)
2055 recipients_list = NULL;
2056 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2057 raw_recipients_count = recipients_count = recipients_list_max = 0;
2058 message_linecount = 0;
2060 message_body = message_body_end = NULL;
2061 acl_added_headers = NULL;
2062 acl_removed_headers = NULL;
2063 f.queue_only_policy = FALSE;
2064 rcpt_smtp_response = NULL;
2065 fl.rcpt_smtp_response_same = TRUE;
2066 fl.rcpt_in_progress = FALSE;
2067 f.deliver_freeze = FALSE; /* Can be set by ACL */
2068 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2069 fake_response = OK; /* Can be set by ACL */
2070 #ifdef WITH_CONTENT_SCAN
2071 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2073 f.submission_mode = FALSE; /* Can be set by ACL */
2074 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2075 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2076 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2077 sending_ip_address = NULL;
2078 return_path = sender_address = NULL;
2079 deliver_localpart_data = deliver_domain_data =
2080 recipient_data = sender_data = NULL; /* Can be set by ACL */
2081 recipient_verify_failure = NULL;
2082 deliver_localpart_parent = deliver_localpart_orig = NULL;
2083 deliver_domain_parent = deliver_domain_orig = NULL;
2084 callout_address = NULL;
2085 submission_name = NULL; /* Can be set by ACL */
2086 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2087 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2088 sender_verified_list = NULL; /* No senders verified */
2089 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2090 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2092 authenticated_sender = NULL;
2093 #ifdef EXPERIMENTAL_BRIGHTMAIL
2095 bmi_verdicts = NULL;
2097 dnslist_domain = dnslist_matched = NULL;
2099 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2100 spf_result_guessed = FALSE;
2102 #ifndef DISABLE_DKIM
2103 dkim_cur_signer = dkim_signers =
2104 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2105 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2106 f.dkim_disable_verify = FALSE;
2107 dkim_collect_input = 0;
2108 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2109 dkim_key_length = 0;
2111 #ifdef SUPPORT_DMARC
2112 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2113 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2114 dmarc_used_domain = NULL;
2116 #ifdef EXPERIMENTAL_ARC
2117 arc_state = arc_state_reason = NULL;
2118 arc_received_instance = 0;
2122 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2123 #ifndef DISABLE_PRDR
2124 prdr_requested = FALSE;
2127 message_smtputf8 = FALSE;
2129 body_linecount = body_zerocount = 0;
2131 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2132 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2133 /* Note that ratelimiters_conn persists across resets. */
2135 /* Reset message ACL variables */
2139 /* Warning log messages are saved in malloc store. They are saved to avoid
2140 repetition in the same message, but it seems right to repeat them for different
2143 while (acl_warn_logged)
2145 string_item *this = acl_warn_logged;
2146 acl_warn_logged = acl_warn_logged->next;
2151 store_reset(reset_point);
2154 return store_mark();
2161 /*************************************************
2162 * Initialize for incoming batched SMTP message *
2163 *************************************************/
2165 /* This function is called from smtp_setup_msg() in the case when
2166 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2167 of messages in one file with SMTP commands between them. All errors must be
2168 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2169 relevant. After an error on a sender, or an invalid recipient, the remainder
2170 of the message is skipped. The value of received_protocol is already set.
2173 Returns: > 0 message successfully started (reached DATA)
2174 = 0 QUIT read or end of file reached
2175 < 0 should not occur
2179 smtp_setup_batch_msg(void)
2182 rmark reset_point = store_mark();
2184 /* Save the line count at the start of each transaction - single commands
2185 like HELO and RSET count as whole transactions. */
2187 bsmtp_transaction_linecount = receive_linecount;
2189 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2191 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2192 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2194 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2195 value. The values are 2 larger than the required yield of the function. */
2200 uschar *recipient = NULL;
2201 int start, end, sender_domain, recipient_domain;
2203 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2205 /* The HELO/EHLO commands set sender_address_helo if they have
2206 valid data; otherwise they are ignored, except that they do
2207 a reset of the state. */
2212 check_helo(smtp_cmd_data);
2216 cancel_cutthrough_connection(TRUE, US"RSET received");
2217 reset_point = smtp_reset(reset_point);
2218 bsmtp_transaction_linecount = receive_linecount;
2222 /* The MAIL FROM command requires an address as an operand. All we
2223 do here is to parse it for syntactic correctness. The form "<>" is
2224 a special case which converts into an empty string. The start/end
2225 pointers in the original are not used further for this address, as
2226 it is the canonical extracted address which is all that is kept. */
2229 smtp_mailcmd_count++; /* Count for no-mail log */
2231 /* The function moan_smtp_batch() does not return. */
2232 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2234 if (smtp_cmd_data[0] == 0)
2235 /* The function moan_smtp_batch() does not return. */
2236 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2238 /* Reset to start of message */
2240 cancel_cutthrough_connection(TRUE, US"MAIL received");
2241 reset_point = smtp_reset(reset_point);
2243 /* Apply SMTP rewrite */
2245 raw_sender = rewrite_existflags & rewrite_smtp
2246 /* deconst ok as smtp_cmd_data was not const */
2247 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2248 FALSE, US"", global_rewrite_rules)
2251 /* Extract the address; the TRUE flag allows <> as valid */
2254 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2258 /* The function moan_smtp_batch() does not return. */
2259 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2261 sender_address = string_copy(raw_sender);
2263 /* Qualify unqualified sender addresses if permitted to do so. */
2266 && sender_address[0] != 0 && sender_address[0] != '@')
2267 if (f.allow_unqualified_sender)
2269 /* deconst ok as sender_address was not const */
2270 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2271 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2272 "and rewritten\n", raw_sender);
2274 /* The function moan_smtp_batch() does not return. */
2276 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2281 /* The RCPT TO command requires an address as an operand. All we do
2282 here is to parse it for syntactic correctness. There may be any number
2283 of RCPT TO commands, specifying multiple senders. We build them all into
2284 a data structure that is in argc/argv format. The start/end values
2285 given by parse_extract_address are not used, as we keep only the
2286 extracted address. */
2289 if (!sender_address)
2290 /* The function moan_smtp_batch() does not return. */
2291 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2293 if (smtp_cmd_data[0] == 0)
2294 /* The function moan_smtp_batch() does not return. */
2295 moan_smtp_batch(smtp_cmd_buffer,
2296 "501 RCPT TO must have an address operand");
2298 /* Check maximum number allowed */
2300 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2301 /* The function moan_smtp_batch() does not return. */
2302 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2303 recipients_max_reject? "552": "452");
2305 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2306 recipient address */
2308 recipient = rewrite_existflags & rewrite_smtp
2309 /* deconst ok as smtp_cmd_data was not const */
2310 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2311 global_rewrite_rules)
2314 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2315 &recipient_domain, FALSE);
2318 /* The function moan_smtp_batch() does not return. */
2319 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2321 /* If the recipient address is unqualified, qualify it if permitted. Then
2322 add it to the list of recipients. */
2324 if (!recipient_domain)
2325 if (f.allow_unqualified_recipient)
2327 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2329 /* deconst ok as recipient was not const */
2330 recipient = US rewrite_address_qualify(recipient, TRUE);
2332 /* The function moan_smtp_batch() does not return. */
2334 moan_smtp_batch(smtp_cmd_buffer,
2335 "501 recipient address must contain a domain");
2337 receive_add_recipient(recipient, -1);
2341 /* The DATA command is legal only if it follows successful MAIL FROM
2342 and RCPT TO commands. This function is complete when a valid DATA
2343 command is encountered. */
2346 if (!sender_address || recipients_count <= 0)
2347 /* The function moan_smtp_batch() does not return. */
2348 if (!sender_address)
2349 moan_smtp_batch(smtp_cmd_buffer,
2350 "503 MAIL FROM:<sender> command must precede DATA");
2352 moan_smtp_batch(smtp_cmd_buffer,
2353 "503 RCPT TO:<recipient> must precede DATA");
2356 done = 3; /* DATA successfully achieved */
2357 message_ended = END_NOTENDED; /* Indicate in middle of message */
2362 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2369 bsmtp_transaction_linecount = receive_linecount;
2374 f.smtp_in_quit = TRUE;
2381 /* The function moan_smtp_batch() does not return. */
2382 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2387 /* The function moan_smtp_batch() does not return. */
2388 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2393 /* The function moan_smtp_batch() does not return. */
2394 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2399 return done - 2; /* Convert yield values */
2407 smtp_log_tls_fail(uschar * errstr)
2409 uschar * conn_info = smtp_get_connection_info();
2411 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2412 /* I'd like to get separated H= here, but too hard for now */
2414 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2428 socklen_t len = sizeof(is_fastopen);
2430 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2431 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2433 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2438 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2439 f.tcp_in_fastopen = TRUE;
2442 else DEBUG(D_receive)
2443 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2445 # elif defined(TCP_INFO)
2446 struct tcp_info tinfo;
2447 socklen_t len = sizeof(tinfo);
2449 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2450 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2451 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2454 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2455 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2459 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2462 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2463 f.tcp_in_fastopen = TRUE;
2465 else DEBUG(D_receive)
2466 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2472 /*************************************************
2473 * Start an SMTP session *
2474 *************************************************/
2476 /* This function is called at the start of an SMTP session. Thereafter,
2477 smtp_setup_msg() is called to initiate each separate message. This
2478 function does host-specific testing, and outputs the banner line.
2481 Returns: FALSE if the session can not continue; something has
2482 gone wrong, or the connection to the host is blocked
2486 smtp_start_session(void)
2489 uschar *user_msg, *log_msg;
2494 gettimeofday(&smtp_connection_start, NULL);
2495 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2496 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2499 /* Default values for certain variables */
2501 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2502 smtp_mailcmd_count = 0;
2503 count_nonmail = TRUE_UNSET;
2504 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2505 smtp_delay_mail = smtp_rlm_base;
2506 fl.auth_advertised = FALSE;
2507 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2508 f.pipelining_enable = TRUE;
2509 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2510 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2512 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2513 authentication settings from -oMaa to remain in force. */
2515 if (!host_checking && !f.sender_host_notsocket)
2516 sender_host_auth_pubname = sender_host_authenticated = NULL;
2517 authenticated_by = NULL;
2520 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2521 tls_in.ourcert = tls_in.peercert = NULL;
2523 tls_in.ocsp = OCSP_NOT_REQ;
2524 fl.tls_advertised = FALSE;
2526 fl.dsn_advertised = FALSE;
2528 fl.smtputf8_advertised = FALSE;
2531 /* Reset ACL connection variables */
2535 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2537 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2539 smtp_cmd_buffer[0] = 0;
2540 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2542 /* For batched input, the protocol setting can be overridden from the
2543 command line by a trusted caller. */
2545 if (smtp_batched_input)
2547 if (!received_protocol) received_protocol = US"local-bsmtp";
2550 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2551 reset later if any of EHLO/AUTH/STARTTLS are received. */
2555 (sender_host_address ? protocols : protocols_local) [pnormal];
2557 /* Set up the buffer for inputting using direct read() calls, and arrange to
2558 call the local functions instead of the standard C ones. Place a NUL at the
2559 end of the buffer to safety-stop C-string reads from it. */
2561 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2562 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2563 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2565 receive_getc = smtp_getc;
2566 receive_getbuf = smtp_getbuf;
2567 receive_get_cache = smtp_get_cache;
2568 receive_ungetc = smtp_ungetc;
2569 receive_feof = smtp_feof;
2570 receive_ferror = smtp_ferror;
2571 receive_smtp_buffered = smtp_buffered;
2572 lwr_receive_getc = NULL;
2573 lwr_receive_getbuf = NULL;
2574 lwr_receive_ungetc = NULL;
2575 smtp_inptr = smtp_inend = smtp_inbuffer;
2576 smtp_had_eof = smtp_had_error = 0;
2578 /* Set up the message size limit; this may be host-specific */
2580 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2581 if (expand_string_message)
2583 if (thismessage_size_limit == -1)
2584 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2585 "%s", expand_string_message);
2587 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2588 "%s", expand_string_message);
2589 smtp_closedown(US"Temporary local problem - please try later");
2593 /* When a message is input locally via the -bs or -bS options, sender_host_
2594 unknown is set unless -oMa was used to force an IP address, in which case it
2595 is checked like a real remote connection. When -bs is used from inetd, this
2596 flag is not set, causing the sending host to be checked. The code that deals
2597 with IP source routing (if configured) is never required for -bs or -bS and
2598 the flag sender_host_notsocket is used to suppress it.
2600 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2601 reserve for certain hosts and/or networks. */
2603 if (!f.sender_host_unknown)
2606 BOOL reserved_host = FALSE;
2608 /* Look up IP options (source routing info) on the socket if this is not an
2609 -oMa "host", and if any are found, log them and drop the connection.
2611 Linux (and others now, see below) is different to everyone else, so there
2612 has to be some conditional compilation here. Versions of Linux before 2.1.15
2613 used a structure whose name was "options". Somebody finally realized that
2614 this name was silly, and it got changed to "ip_options". I use the
2615 newer name here, but there is a fudge in the script that sets up os.h
2616 to define a macro in older Linux systems.
2618 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2619 glibc 2, which has chosen ip_opts for the structure name. This is now
2620 really a glibc thing rather than a Linux thing, so the condition name
2621 has been changed to reflect this. It is relevant also to GNU/Hurd.
2623 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2624 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2625 a special macro defined in the os.h file.
2627 Some DGUX versions on older hardware appear not to support IP options at
2628 all, so there is now a general macro which can be set to cut out this
2631 How to do this properly in IPv6 is not yet known. */
2633 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2635 #ifdef GLIBC_IP_OPTIONS
2636 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2641 #elif defined DARWIN_IP_OPTIONS
2647 if (!host_checking && !f.sender_host_notsocket)
2650 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2651 struct ip_options *ipopt = store_get(optlen, FALSE);
2653 struct ip_opts ipoptblock;
2654 struct ip_opts *ipopt = &ipoptblock;
2655 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2657 struct ipoption ipoptblock;
2658 struct ipoption *ipopt = &ipoptblock;
2659 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2662 /* Occasional genuine failures of getsockopt() have been seen - for
2663 example, "reset by peer". Therefore, just log and give up on this
2664 call, unless the error is ENOPROTOOPT. This error is given by systems
2665 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2666 of writing. So for that error, carry on - we just can't do an IP options
2669 DEBUG(D_receive) debug_printf("checking for IP options\n");
2671 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2674 if (errno != ENOPROTOOPT)
2676 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2677 host_and_ident(FALSE), strerror(errno));
2678 smtp_printf("451 SMTP service not available\r\n", FALSE);
2683 /* Deal with any IP options that are set. On the systems I have looked at,
2684 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2685 more logging data than will fit in big_buffer. Nevertheless, after somebody
2686 questioned this code, I've added in some paranoid checking. */
2688 else if (optlen > 0)
2690 uschar *p = big_buffer;
2691 uschar *pend = big_buffer + big_buffer_size;
2694 struct in_addr addr;
2697 uschar *optstart = US (ipopt->__data);
2699 uschar *optstart = US (ipopt->ip_opts);
2701 uschar *optstart = US (ipopt->ipopt_list);
2704 DEBUG(D_receive) debug_printf("IP options exist\n");
2706 Ustrcpy(p, "IP options on incoming call:");
2709 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2722 if (!string_format(p, pend-p, " %s [@%s",
2723 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2725 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2727 inet_ntoa(ipopt->ip_dst)))
2729 inet_ntoa(ipopt->ipopt_dst)))
2737 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2739 while (optcount-- > 0)
2741 memcpy(&addr, adptr, sizeof(addr));
2742 if (!string_format(p, pend - p - 1, "%s%s",
2743 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2749 adptr += sizeof(struct in_addr);
2757 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2760 for (int i = 0; i < opt[1]; i++)
2761 p += sprintf(CS p, "%2.2x ", opt[i]);
2769 log_write(0, LOG_MAIN, "%s", big_buffer);
2771 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2773 log_write(0, LOG_MAIN|LOG_REJECT,
2774 "connection from %s refused (IP options)", host_and_ident(FALSE));
2776 smtp_printf("554 SMTP service not available\r\n", FALSE);
2780 /* Length of options = 0 => there are no options */
2782 else DEBUG(D_receive) debug_printf("no IP options found\n");
2784 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2786 /* Set keep-alive in socket options. The option is on by default. This
2787 setting is an attempt to get rid of some hanging connections that stick in
2788 read() when the remote end (usually a dialup) goes away. */
2790 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2791 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2793 /* If the current host matches host_lookup, set the name by doing a
2794 reverse lookup. On failure, sender_host_name will be NULL and
2795 host_lookup_failed will be TRUE. This may or may not be serious - optional
2798 if (verify_check_host(&host_lookup) == OK)
2800 (void)host_name_lookup();
2801 host_build_sender_fullhost();
2804 /* Delay this until we have the full name, if it is looked up. */
2806 set_process_info("handling incoming connection from %s",
2807 host_and_ident(FALSE));
2809 /* Expand smtp_receive_timeout, if needed */
2811 if (smtp_receive_timeout_s)
2814 if ( !(exp = expand_string(smtp_receive_timeout_s))
2816 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2818 log_write(0, LOG_MAIN|LOG_PANIC,
2819 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2822 /* Test for explicit connection rejection */
2824 if (verify_check_host(&host_reject_connection) == OK)
2826 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2827 "from %s (host_reject_connection)", host_and_ident(FALSE));
2828 smtp_printf("554 SMTP service not available\r\n", FALSE);
2832 /* Test with TCP Wrappers if so configured. There is a problem in that
2833 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2834 such as disks dying. In these cases, it is desirable to reject with a 4xx
2835 error instead of a 5xx error. There isn't a "right" way to detect such
2836 problems. The following kludge is used: errno is zeroed before calling
2837 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2838 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2841 #ifdef USE_TCP_WRAPPERS
2843 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2844 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2845 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2846 expand_string_message);
2848 if (!hosts_ctl(tcp_wrappers_name,
2849 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2850 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2851 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2853 if (errno == 0 || errno == ENOENT)
2855 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2856 log_write(L_connection_reject,
2857 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2858 "(tcp wrappers)", host_and_ident(FALSE));
2859 smtp_printf("554 SMTP service not available\r\n", FALSE);
2863 int save_errno = errno;
2864 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2865 "errno value %d\n", save_errno);
2866 log_write(L_connection_reject,
2867 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2868 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2869 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2875 /* Check for reserved slots. The value of smtp_accept_count has already been
2876 incremented to include this process. */
2878 if (smtp_accept_max > 0 &&
2879 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2881 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2883 log_write(L_connection_reject,
2884 LOG_MAIN, "temporarily refused connection from %s: not in "
2885 "reserve list: connected=%d max=%d reserve=%d%s",
2886 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2887 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2888 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2889 "please try again later\r\n", FALSE, smtp_active_hostname);
2892 reserved_host = TRUE;
2895 /* If a load level above which only messages from reserved hosts are
2896 accepted is set, check the load. For incoming calls via the daemon, the
2897 check is done in the superior process if there are no reserved hosts, to
2898 save a fork. In all cases, the load average will already be available
2899 in a global variable at this point. */
2901 if (smtp_load_reserve >= 0 &&
2902 load_average > smtp_load_reserve &&
2904 verify_check_host(&smtp_reserve_hosts) != OK)
2906 log_write(L_connection_reject,
2907 LOG_MAIN, "temporarily refused connection from %s: not in "
2908 "reserve list and load average = %.2f", host_and_ident(FALSE),
2909 (double)load_average/1000.0);
2910 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2911 smtp_active_hostname);
2915 /* Determine whether unqualified senders or recipients are permitted
2916 for this host. Unfortunately, we have to do this every time, in order to
2917 set the flags so that they can be inspected when considering qualifying
2918 addresses in the headers. For a site that permits no qualification, this
2919 won't take long, however. */
2921 f.allow_unqualified_sender =
2922 verify_check_host(&sender_unqualified_hosts) == OK;
2924 f.allow_unqualified_recipient =
2925 verify_check_host(&recipient_unqualified_hosts) == OK;
2927 /* Determine whether HELO/EHLO is required for this host. The requirement
2928 can be hard or soft. */
2930 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2931 if (!fl.helo_required)
2932 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2934 /* Determine whether this hosts is permitted to send syntactic junk
2935 after a HELO or EHLO command. */
2937 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2940 /* For batch SMTP input we are now done. */
2942 if (smtp_batched_input) return TRUE;
2944 /* If valid Proxy Protocol source is connecting, set up session.
2945 Failure will not allow any SMTP function other than QUIT. */
2947 #ifdef SUPPORT_PROXY
2948 proxy_session = FALSE;
2949 f.proxy_session_failed = FALSE;
2950 if (check_proxy_protocol_host())
2951 setup_proxy_protocol_host();
2954 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2955 smtps port for use with older style SSL MTAs. */
2958 if (tls_in.on_connect)
2960 if (tls_server_start(&user_msg) != OK)
2961 return smtp_log_tls_fail(user_msg);
2962 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2966 /* Run the connect ACL if it exists */
2969 if (acl_smtp_connect)
2972 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2975 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2980 /* Output the initial message for a two-way SMTP connection. It may contain
2981 newlines, which then cause a multi-line response to be given. */
2983 code = US"220"; /* Default status code */
2984 esc = US""; /* Default extended status code */
2985 esclen = 0; /* Length of esc */
2989 if (!(s = expand_string(smtp_banner)))
2990 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2991 "failed: %s", smtp_banner, expand_string_message);
2997 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3001 esclen = codelen - 4;
3005 /* Remove any terminating newlines; might as well remove trailing space too */
3008 while (p > s && isspace(p[-1])) p--;
3011 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3012 is all contained in a single IP packet. The original code wrote out the
3013 greeting using several calls to fprint/fputc, and on busy servers this could
3014 cause it to be split over more than one packet - which caused CC:Mail to fall
3015 over when it got the second part of the greeting after sending its first
3016 command. Sigh. To try to avoid this, build the complete greeting message
3017 first, and output it in one fell swoop. This gives a better chance of it
3018 ending up as a single packet. */
3020 ss = string_get(256);
3023 do /* At least once, in case we have an empty string */
3026 uschar *linebreak = Ustrchr(p, '\n');
3027 ss = string_catn(ss, code, 3);
3031 ss = string_catn(ss, US" ", 1);
3035 len = linebreak - p;
3036 ss = string_catn(ss, US"-", 1);
3038 ss = string_catn(ss, esc, esclen);
3039 ss = string_catn(ss, p, len);
3040 ss = string_catn(ss, US"\r\n", 2);
3046 /* Before we write the banner, check that there is no input pending, unless
3047 this synchronisation check is disabled. */
3049 #ifndef DISABLE_PIPE_CONNECT
3050 fl.pipe_connect_acceptable =
3051 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3054 if (fl.pipe_connect_acceptable)
3055 f.smtp_in_early_pipe_used = TRUE;
3061 unsigned n = smtp_inend - smtp_inptr;
3062 if (n > 128) n = 128;
3064 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3065 "synchronization error (input sent without waiting for greeting): "
3066 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3067 string_printing(string_copyn(smtp_inptr, n)));
3068 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3072 /* Now output the banner */
3073 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3076 #ifndef DISABLE_PIPE_CONNECT
3077 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3081 string_from_gstring(ss));
3083 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3084 handshake arrived. If so we must have managed a TFO. */
3087 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3097 /*************************************************
3098 * Handle SMTP syntax and protocol errors *
3099 *************************************************/
3101 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3102 to do so. Then transmit the error response. The return value depends on the
3103 number of syntax and protocol errors in this SMTP session.
3106 type error type, given as a log flag bit
3107 code response code; <= 0 means don't send a response
3108 data data to reflect in the response (can be NULL)
3109 errmess the error message
3111 Returns: -1 limit of syntax/protocol errors NOT exceeded
3112 +1 limit of syntax/protocol errors IS exceeded
3114 These values fit in with the values of the "done" variable in the main
3115 processing loop in smtp_setup_msg(). */
3118 synprot_error(int type, int code, uschar *data, uschar *errmess)
3122 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3123 type == L_smtp_syntax_error ? "syntax" : "protocol",
3124 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3126 if (++synprot_error_count > smtp_max_synprot_errors)
3129 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3130 "syntax or protocol errors (last command was \"%s\", %s)",
3131 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3132 string_from_gstring(s_connhad_log(NULL))
3138 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3139 data ? data : US"", data ? US": " : US"", errmess);
3141 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3150 /*************************************************
3151 * Send SMTP response, possibly multiline *
3152 *************************************************/
3154 /* There are, it seems, broken clients out there that cannot handle multiline
3155 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3156 output nothing for non-final calls, and only the first line for anything else.
3159 code SMTP code, may involve extended status codes
3160 codelen length of smtp code; if > 4 there's an ESC
3161 final FALSE if the last line isn't the final line
3162 msg message text, possibly containing newlines
3168 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3173 if (!final && f.no_multiline_responses) return;
3178 esclen = codelen - 4;
3181 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3182 have had the same. Note: this code is also present in smtp_printf(). It would
3183 be tidier to have it only in one place, but when it was added, it was easier to
3184 do it that way, so as not to have to mess with the code for the RCPT command,
3185 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3187 if (fl.rcpt_in_progress)
3189 if (rcpt_smtp_response == NULL)
3190 rcpt_smtp_response = string_copy(msg);
3191 else if (fl.rcpt_smtp_response_same &&
3192 Ustrcmp(rcpt_smtp_response, msg) != 0)
3193 fl.rcpt_smtp_response_same = FALSE;
3194 fl.rcpt_in_progress = FALSE;
3197 /* Now output the message, splitting it up into multiple lines if necessary.
3198 We only handle pipelining these responses as far as nonfinal/final groups,
3199 not the whole MAIL/RCPT/DATA response set. */
3203 uschar *nl = Ustrchr(msg, '\n');
3206 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3209 else if (nl[1] == 0 || f.no_multiline_responses)
3211 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3212 (int)(nl - msg), msg);
3217 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3219 Uskip_whitespace(&msg);
3227 /*************************************************
3228 * Parse user SMTP message *
3229 *************************************************/
3231 /* This function allows for user messages overriding the response code details
3232 by providing a suitable response code string at the start of the message
3233 user_msg. Check the message for starting with a response code and optionally an
3234 extended status code. If found, check that the first digit is valid, and if so,
3235 change the code pointer and length to use the replacement. An invalid code
3236 causes a panic log; in this case, if the log messages is the same as the user
3237 message, we must also adjust the value of the log message to show the code that
3238 is actually going to be used (the original one).
3240 This function is global because it is called from receive.c as well as within
3243 Note that the code length returned includes the terminating whitespace
3244 character, which is always included in the regex match.
3247 code SMTP code, may involve extended status codes
3248 codelen length of smtp code; if > 4 there's an ESC
3250 log_msg optional log message, to be adjusted with the new SMTP code
3251 check_valid if true, verify the response code
3257 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3263 if (!msg || !*msg) return;
3265 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3266 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3268 if (check_valid && (*msg)[0] != (*code)[0])
3270 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3271 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3272 if (log_msg != NULL && *log_msg == *msg)
3273 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3278 *codelen = ovector[1]; /* Includes final space */
3280 *msg += ovector[1]; /* Chop the code off the message */
3287 /*************************************************
3288 * Handle an ACL failure *
3289 *************************************************/
3291 /* This function is called when acl_check() fails. As well as calls from within
3292 this module, it is called from receive.c for an ACL after DATA. It sorts out
3293 logging the incident, and sends the error response. A message containing
3294 newlines is turned into a multiline SMTP response, but for logging, only the
3297 There's a table of default permanent failure response codes to use in
3298 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3299 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3300 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3301 state, because there are broken clients that try VRFY before RCPT. A 5xx
3302 response should be given only when the address is positively known to be
3303 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3304 no explicit code, but if there is one we let it know best.
3305 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3307 From Exim 4.63, it is possible to override the response code details by
3308 providing a suitable response code string at the start of the message provided
3309 in user_msg. The code's first digit is checked for validity.
3312 where where the ACL was called from
3314 user_msg a message that can be included in an SMTP response
3315 log_msg a message for logging
3317 Returns: 0 in most cases
3318 2 if the failure code was FAIL_DROP, in which case the
3319 SMTP connection should be dropped (this value fits with the
3320 "done" variable in smtp_setup_msg() below)
3324 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3326 BOOL drop = rc == FAIL_DROP;
3330 uschar *sender_info = US"";
3333 if (drop) rc = FAIL;
3335 /* Set the default SMTP code, and allow a user message to change it. */
3337 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3338 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3339 where != ACL_WHERE_VRFY);
3341 /* We used to have sender_address here; however, there was a bug that was not
3342 updating sender_address after a rewrite during a verify. When this bug was
3343 fixed, sender_address at this point became the rewritten address. I'm not sure
3344 this is what should be logged, so I've changed to logging the unrewritten
3345 address to retain backward compatibility. */
3349 #ifdef WITH_CONTENT_SCAN
3350 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3352 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3353 case ACL_WHERE_DATA: what = US"after DATA"; break;
3354 #ifndef DISABLE_PRDR
3355 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3359 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3362 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3365 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
3366 lim = s - smtp_cmd_data; /* atop after method */
3368 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3373 case ACL_WHERE_RCPT:
3374 case ACL_WHERE_DATA:
3375 #ifdef WITH_CONTENT_SCAN
3376 case ACL_WHERE_MIME:
3378 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3379 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3380 sender_host_authenticated ? US" A=" : US"",
3381 sender_host_authenticated ? sender_host_authenticated : US"",
3382 sender_host_authenticated && authenticated_id ? US":" : US"",
3383 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3388 /* If there's been a sender verification failure with a specific message, and
3389 we have not sent a response about it yet, do so now, as a preliminary line for
3390 failures, but not defers. However, always log it for defer, and log it for fail
3391 unless the sender_verify_fail log selector has been turned off. */
3393 if (sender_verified_failed &&
3394 !testflag(sender_verified_failed, af_sverify_told))
3396 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3397 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3399 setflag(sender_verified_failed, af_sverify_told);
3401 if (rc != FAIL || LOGGING(sender_verify_fail))
3402 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3403 host_and_ident(TRUE),
3404 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3405 sender_verified_failed->address,
3406 (sender_verified_failed->message == NULL)? US"" :
3407 string_sprintf(": %s", sender_verified_failed->message));
3409 if (rc == FAIL && sender_verified_failed->user_message)
3410 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3411 testflag(sender_verified_failed, af_verify_pmfail)?
3412 "Postmaster verification failed while checking <%s>\n%s\n"
3413 "Several RFCs state that you are required to have a postmaster\n"
3414 "mailbox for each mail domain. This host does not accept mail\n"
3415 "from domains whose servers reject the postmaster address."
3417 testflag(sender_verified_failed, af_verify_nsfail)?
3418 "Callback setup failed while verifying <%s>\n%s\n"
3419 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3420 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3421 "RFC requirements, and stops you from receiving standard bounce\n"
3422 "messages. This host does not accept mail from domains whose servers\n"
3425 "Verification failed for <%s>\n%s",
3426 sender_verified_failed->address,
3427 sender_verified_failed->user_message));
3429 fl.rcpt_in_progress = save_rcpt_in_progress;
3432 /* Sort out text for logging */
3434 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3435 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3437 /* Send permanent failure response to the command, but the code used isn't
3438 always a 5xx one - see comments at the start of this function. If the original
3439 rc was FAIL_DROP we drop the connection and yield 2. */
3442 smtp_respond(smtp_code, codelen, TRUE,
3443 user_msg ? user_msg : US"Administrative prohibition");
3445 /* Send temporary failure response to the command. Don't give any details,
3446 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3447 verb, and for a header verify when smtp_return_error_details is set.
3449 This conditional logic is all somewhat of a mess because of the odd
3450 interactions between temp_details and return_error_details. One day it should
3451 be re-implemented in a tidier fashion. */
3454 if (f.acl_temp_details && user_msg)
3456 if ( smtp_return_error_details
3457 && sender_verified_failed
3458 && sender_verified_failed->message
3460 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3462 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3465 smtp_respond(smtp_code, codelen, TRUE,
3466 US"Temporary local problem - please try later");
3468 /* Log the incident to the logs that are specified by log_reject_target
3469 (default main, reject). This can be empty to suppress logging of rejections. If
3470 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3471 is closing if required and return 2. */
3473 if (log_reject_target != 0)
3476 gstring * g = s_tlslog(NULL);
3477 uschar * tls = string_from_gstring(g);
3478 if (!tls) tls = US"";
3480 uschar * tls = US"";
3482 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3483 log_reject_target, "%s%s%s %s%srejected %s%s",
3484 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3485 host_and_ident(TRUE),
3488 rc == FAIL ? US"" : US"temporarily ",
3492 if (!drop) return 0;
3494 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3495 smtp_get_connection_info());
3497 /* Run the not-quit ACL, but without any custom messages. This should not be a
3498 problem, because we get here only if some other ACL has issued "drop", and
3499 in that case, *its* custom messages will have been used above. */
3501 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3508 /*************************************************
3509 * Handle SMTP exit when QUIT is not given *
3510 *************************************************/
3512 /* This function provides a logging/statistics hook for when an SMTP connection
3513 is dropped on the floor or the other end goes away. It's a global function
3514 because it's called from receive.c as well as this module. As well as running
3515 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3516 response, either with a custom message from the ACL, or using a default. There
3517 is one case, however, when no message is output - after "drop". In that case,
3518 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3519 passed to this function.
3521 In case things go wrong while processing this function, causing an error that
3522 may re-enter this function, there is a recursion check.
3525 reason What $smtp_notquit_reason will be set to in the ACL;
3526 if NULL, the ACL is not run
3527 code The error code to return as part of the response
3528 defaultrespond The default message if there's no user_msg
3534 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3537 uschar *user_msg = NULL;
3538 uschar *log_msg = NULL;
3540 /* Check for recursive call */
3542 if (fl.smtp_exit_function_called)
3544 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3548 fl.smtp_exit_function_called = TRUE;
3550 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3552 if (acl_smtp_notquit && reason)
3554 smtp_notquit_reason = reason;
3555 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3556 &log_msg)) == ERROR)
3557 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3561 /* If the connection was dropped, we certainly are no longer talking TLS */
3562 tls_in.active.sock = -1;
3564 /* Write an SMTP response if we are expected to give one. As the default
3565 responses are all internal, they should be reasonable size. */
3567 if (code && defaultrespond)
3570 smtp_respond(code, 3, TRUE, user_msg);
3576 va_start(ap, defaultrespond);
3577 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3579 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3588 /*************************************************
3589 * Verify HELO argument *
3590 *************************************************/
3592 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3593 matched. It is also called from ACL processing if verify = helo is used and
3594 verification was not previously tried (i.e. helo_try_verify_hosts was not
3595 matched). The result of its processing is to set helo_verified and
3596 helo_verify_failed. These variables should both be FALSE for this function to
3599 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3600 for IPv6 ::ffff: literals.
3603 Returns: TRUE if testing was completed;
3604 FALSE on a temporary failure
3608 smtp_verify_helo(void)
3612 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3615 if (sender_helo_name == NULL)
3617 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3620 /* Deal with the case of -bs without an IP address */
3622 else if (sender_host_address == NULL)
3624 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3625 f.helo_verified = TRUE;
3628 /* Deal with the more common case when there is a sending IP address */
3630 else if (sender_helo_name[0] == '[')
3632 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3633 Ustrlen(sender_host_address)) == 0;
3636 if (!f.helo_verified)
3638 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3639 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3640 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3645 { if (f.helo_verified) debug_printf("matched host address\n"); }
3648 /* Do a reverse lookup if one hasn't already given a positive or negative
3649 response. If that fails, or the name doesn't match, try checking with a forward
3654 if (sender_host_name == NULL && !host_lookup_failed)
3655 yield = host_name_lookup() != DEFER;
3657 /* If a host name is known, check it and all its aliases. */
3659 if (sender_host_name)
3660 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3662 sender_helo_dnssec = sender_host_dnssec;
3663 HDEBUG(D_receive) debug_printf("matched host name\n");
3667 uschar **aliases = sender_host_aliases;
3669 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3671 sender_helo_dnssec = sender_host_dnssec;
3675 HDEBUG(D_receive) if (f.helo_verified)
3676 debug_printf("matched alias %s\n", *(--aliases));
3679 /* Final attempt: try a forward lookup of the helo name */
3681 if (!f.helo_verified)
3685 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3687 {.request = US"*", .require = US""};
3689 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3691 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3692 NULL, NULL, NULL, &d, NULL, NULL);
3693 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3694 for (host_item * hh = &h; hh; hh = hh->next)
3695 if (Ustrcmp(hh->address, sender_host_address) == 0)
3697 f.helo_verified = TRUE;
3698 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3700 debug_printf("IP address for %s matches calling address\n"
3701 "Forward DNS security status: %sverified\n",
3702 sender_helo_name, sender_helo_dnssec ? "" : "un");
3708 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3715 /*************************************************
3716 * Send user response message *
3717 *************************************************/
3719 /* This function is passed a default response code and a user message. It calls
3720 smtp_message_code() to check and possibly modify the response code, and then
3721 calls smtp_respond() to transmit the response. I put this into a function
3722 just to avoid a lot of repetition.
3725 code the response code
3726 user_msg the user message
3732 smtp_user_msg(uschar *code, uschar *user_msg)
3735 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3736 smtp_respond(code, len, TRUE, user_msg);
3742 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3744 const uschar *set_id = NULL;
3747 /* Run the checking code, passing the remainder of the command line as
3748 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3749 it as the only set numerical variable. The authenticator may set $auth<n>
3750 and also set other numeric variables. The $auth<n> variables are preferred
3751 nowadays; the numerical variables remain for backwards compatibility.
3753 Afterwards, have a go at expanding the set_id string, even if
3754 authentication failed - for bad passwords it can be useful to log the
3755 userid. On success, require set_id to expand and exist, and put it in
3756 authenticated_id. Save this in permanent store, as the working store gets
3757 reset at HELO, RSET, etc. */
3759 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3761 expand_nlength[0] = 0; /* $0 contains nothing */
3763 rc = (au->info->servercode)(au, smtp_cmd_data);
3764 if (au->set_id) set_id = expand_string(au->set_id);
3765 expand_nmax = -1; /* Reset numeric variables */
3766 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3768 /* The value of authenticated_id is stored in the spool file and printed in
3769 log lines. It must not contain binary zeros or newline characters. In
3770 normal use, it never will, but when playing around or testing, this error
3771 can (did) happen. To guard against this, ensure that the id contains only
3772 printing characters. */
3774 if (set_id) set_id = string_printing(set_id);
3776 /* For the non-OK cases, set up additional logging data if set_id
3780 set_id = set_id && *set_id
3781 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3783 /* Switch on the result */
3788 if (!au->set_id || set_id) /* Complete success */
3790 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3791 sender_host_authenticated = au->name;
3792 sender_host_auth_pubname = au->public_name;
3793 authentication_failed = FALSE;
3794 authenticated_fail_id = NULL; /* Impossible to already be set? */
3797 (sender_host_address ? protocols : protocols_local)
3798 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3799 *s = *ss = US"235 Authentication succeeded";
3800 authenticated_by = au;
3804 /* Authentication succeeded, but we failed to expand the set_id string.
3805 Treat this as a temporary error. */
3807 auth_defer_msg = expand_string_message;
3811 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3812 *s = string_sprintf("435 Unable to authenticate at present%s",
3813 auth_defer_user_msg);
3814 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3815 set_id, auth_defer_msg);
3819 *s = *ss = US"501 Invalid base64 data";
3823 *s = *ss = US"501 Authentication cancelled";
3827 *s = *ss = US"553 Initial data not expected";
3831 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3832 *s = US"535 Incorrect authentication data";
3833 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3837 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3838 *s = US"435 Internal error";
3839 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3840 "check", set_id, rc);
3852 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3855 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3857 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3859 rd = Ustrlen(recipient) + 1;
3860 /* deconst ok as *recipient was not const */
3861 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3864 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3866 log_write(L_smtp_syntax_error,
3867 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3868 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3876 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3879 f.smtp_in_quit = TRUE;
3880 incomplete_transaction_log(US"QUIT");
3882 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3884 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3887 #ifdef EXIM_TCP_CORK
3888 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3892 smtp_respond(US"221", 3, TRUE, *user_msgp);
3894 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3896 #ifdef SERVERSIDE_CLOSE_NOWAIT
3897 # ifndef DISABLE_TLS
3898 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3901 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3902 smtp_get_connection_info());
3905 # ifndef DISABLE_TLS
3906 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3909 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3910 smtp_get_connection_info());
3912 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3913 The socket should become readble (though with no data) */
3916 int fd = fileno(smtp_in);
3918 struct timeval t_limit = {.tv_sec = 0, .tv_usec = 200*1000};
3922 (void) select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &t_limit);
3924 #endif /*!DAEMON_CLOSE_NOWAIT*/
3929 smtp_rset_handler(void)
3932 incomplete_transaction_log(US"RSET");
3933 smtp_printf("250 Reset OK\r\n", FALSE);
3934 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3939 expand_mailmax(const uschar * s)
3941 if (!(s = expand_cstring(s)))
3942 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3943 return *s ? Uatoi(s) : 0;
3946 /*************************************************
3947 * Initialize for SMTP incoming message *
3948 *************************************************/
3950 /* This function conducts the initial dialogue at the start of an incoming SMTP
3951 message, and builds a list of recipients. However, if the incoming message
3952 is part of a batch (-bS option) a separate function is called since it would
3953 be messy having tests splattered about all over this function. This function
3954 therefore handles the case where interaction is occurring. The input and output
3955 files are set up in smtp_in and smtp_out.
3957 The global recipients_list is set to point to a vector of recipient_item
3958 blocks, whose number is given by recipients_count. This is extended by the
3959 receive_add_recipient() function. The global variable sender_address is set to
3960 the sender's address. The yield is +1 if a message has been successfully
3961 started, 0 if a QUIT command was encountered or the connection was refused from
3962 the particular host, or -1 if the connection was lost.
3966 Returns: > 0 message successfully started (reached DATA)
3967 = 0 QUIT read or end of file reached or call refused
3972 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();
4020 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4021 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4022 US &off, sizeof(off));
4025 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4026 value. The values are 2 larger than the required yield of the function. */
4030 const uschar **argv;
4031 uschar *etrn_command;
4032 uschar *etrn_serialize_key;
4034 uschar *log_msg, *smtp_code;
4035 uschar *user_msg = NULL;
4036 uschar *recipient = NULL;
4037 uschar *hello = NULL;
4039 BOOL was_rej_mail = FALSE;
4040 BOOL was_rcpt = FALSE;
4041 void (*oldsignal)(int);
4043 int start, end, sender_domain, recipient_domain;
4046 uschar *orcpt = NULL;
4051 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4052 if ( tls_in.active.sock >= 0
4054 && tls_in.certificate_verified
4055 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4058 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4060 for (auth_instance * au = auths; au; au = au->next)
4061 if (strcmpic(US"tls", au->driver_name) == 0)
4064 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4065 &user_msg, &log_msg)) != OK
4067 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4070 smtp_cmd_data = NULL;
4072 if (smtp_in_auth(au, &s, &ss) == OK)
4073 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4075 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
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 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
4143 if (!isalnum(c) && c != '-' && c != '_')
4145 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4146 US"invalid character in authentication mechanism name");
4150 /* If not at the end of the line, we must be at white space. Terminate the
4151 name and move the pointer on to any data that may be present. */
4155 *smtp_cmd_data++ = 0;
4156 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4159 /* Search for an authentication mechanism which is configured for use
4160 as a server and which has been advertised (unless, sigh, allow_auth_
4161 unadvertised is set). */
4165 for (au = auths; au; au = au->next)
4166 if (strcmpic(s, au->public_name) == 0 && au->server &&
4167 (au->advertised || f.allow_auth_unadvertised))
4172 c = smtp_in_auth(au, &s, &ss);
4174 smtp_printf("%s\r\n", FALSE, s);
4176 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4177 au->name, host_and_ident(FALSE), ss);
4180 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4181 string_sprintf("%s authentication mechanism not supported", s));
4184 break; /* AUTH_CMD */
4186 /* The HELO/EHLO commands are permitted to appear in the middle of a
4187 session as well as at the beginning. They have the effect of a reset in
4188 addition to their other functions. Their absence at the start cannot be
4189 taken to be an error.
4193 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4194 or 502 failure replies MUST be returned as appropriate. The SMTP
4195 server MUST stay in the same state after transmitting these replies
4196 that it was in before the EHLO was received.
4198 Therefore, we do not do the reset until after checking the command for
4199 acceptability. This change was made for Exim release 4.11. Previously
4200 it did the reset first. */
4213 HELO_EHLO: /* Common code for HELO and EHLO */
4214 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4215 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4217 /* Reject the HELO if its argument was invalid or non-existent. A
4218 successful check causes the argument to be saved in malloc store. */
4220 if (!check_helo(smtp_cmd_data))
4222 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4224 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4225 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4226 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4227 string_printing(smtp_cmd_argument));
4229 if (++synprot_error_count > smtp_max_synprot_errors)
4231 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4232 "syntax or protocol errors (last command was \"%s\", %s)",
4233 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4234 string_from_gstring(s_connhad_log(NULL))
4242 /* If sender_host_unknown is true, we have got here via the -bs interface,
4243 not called from inetd. Otherwise, we are running an IP connection and the
4244 host address will be set. If the helo name is the primary name of this
4245 host and we haven't done a reverse lookup, force one now. If helo_required
4246 is set, ensure that the HELO name matches the actual host. If helo_verify
4247 is set, do the same check, but softly. */
4249 if (!f.sender_host_unknown)
4251 BOOL old_helo_verified = f.helo_verified;
4252 uschar *p = smtp_cmd_data;
4254 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4257 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4258 because otherwise the log can be confusing. */
4260 if ( !sender_host_name
4261 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4262 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4263 (void)host_name_lookup();
4265 /* Rebuild the fullhost info to include the HELO name (and the real name
4266 if it was looked up.) */
4268 host_build_sender_fullhost(); /* Rebuild */
4269 set_process_info("handling%s incoming connection from %s",
4270 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4272 /* Verify if configured. This doesn't give much security, but it does
4273 make some people happy to be able to do it. If helo_required is set,
4274 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4275 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4276 now obsolescent, since the verification can now be requested selectively
4279 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4280 if (fl.helo_required || fl.helo_verify)
4282 BOOL tempfail = !smtp_verify_helo();
4283 if (!f.helo_verified)
4285 if (fl.helo_required)
4287 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4288 tempfail? 451 : 550, hello);
4289 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4290 tempfail? "temporarily " : "",
4291 hello, sender_helo_name, host_and_ident(FALSE));
4292 f.helo_verified = old_helo_verified;
4293 break; /* End of HELO/EHLO processing */
4295 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4296 "helo_try_verify_hosts\n", hello);
4302 /* set up SPF context */
4303 spf_conn_init(sender_helo_name, sender_host_address);
4306 /* Apply an ACL check if one is defined; afterwards, recheck
4307 synchronization in case the client started sending in a delay. */
4310 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4311 &user_msg, &log_msg)) != OK)
4313 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4314 sender_helo_name = NULL;
4315 host_build_sender_fullhost(); /* Rebuild */
4318 #ifndef DISABLE_PIPE_CONNECT
4319 else if (!fl.pipe_connect_acceptable && !check_sync())
4321 else if (!check_sync())
4325 /* Generate an OK reply. The default string includes the ident if present,
4326 and also the IP address if present. Reflecting back the ident is intended
4327 as a deterrent to mail forgers. For maximum efficiency, and also because
4328 some broken systems expect each response to be in a single packet, arrange
4329 that the entire reply is sent in one write(). */
4331 fl.auth_advertised = FALSE;
4332 f.smtp_in_pipelining_advertised = FALSE;
4334 fl.tls_advertised = FALSE;
4336 fl.dsn_advertised = FALSE;
4338 fl.smtputf8_advertised = FALSE;
4341 /* Expand the per-connection message count limit option */
4342 mailmax = expand_mailmax(smtp_accept_max_per_connection);
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 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4404 if ( (mailmax > 0 || recipients_max)
4405 && verify_check_host(&limits_advertise_hosts) == OK)
4407 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4409 g = string_fmt_append(g, " MAILMAX=%d", mailmax);
4411 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4412 g = string_catn(g, US"\r\n", 2);
4416 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4417 clean; if it has an 8-bit character in its hand, it just sends it. It
4418 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4419 However, some users want this option simply in order to stop MUAs
4420 mangling messages that contain top-bit-set characters. It is therefore
4421 provided as an option. */
4423 if (accept_8bitmime)
4425 g = string_catn(g, smtp_code, 3);
4426 g = string_catn(g, US"-8BITMIME\r\n", 11);
4429 /* Advertise DSN support if configured to do so. */
4430 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4432 g = string_catn(g, smtp_code, 3);
4433 g = string_catn(g, US"-DSN\r\n", 6);
4434 fl.dsn_advertised = TRUE;
4437 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4438 permitted to issue them; a check is made when any host actually tries. */
4442 g = string_catn(g, smtp_code, 3);
4443 g = string_catn(g, US"-ETRN\r\n", 7);
4447 g = string_catn(g, smtp_code, 3);
4448 g = string_catn(g, US"-VRFY\r\n", 7);
4452 g = string_catn(g, smtp_code, 3);
4453 g = string_catn(g, US"-EXPN\r\n", 7);
4456 /* Exim is quite happy with pipelining, so let the other end know that
4457 it is safe to use it, unless advertising is disabled. */
4459 if ( f.pipelining_enable
4460 && verify_check_host(&pipelining_advertise_hosts) == OK)
4462 g = string_catn(g, smtp_code, 3);
4463 g = string_catn(g, US"-PIPELINING\r\n", 13);
4464 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4465 f.smtp_in_pipelining_advertised = TRUE;
4467 #ifndef DISABLE_PIPE_CONNECT
4468 if (fl.pipe_connect_acceptable)
4470 f.smtp_in_early_pipe_advertised = TRUE;
4471 g = string_catn(g, smtp_code, 3);
4472 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4478 /* If any server authentication mechanisms are configured, advertise
4479 them if the current host is in auth_advertise_hosts. The problem with
4480 advertising always is that some clients then require users to
4481 authenticate (and aren't configurable otherwise) even though it may not
4482 be necessary (e.g. if the host is in host_accept_relay).
4484 RFC 2222 states that SASL mechanism names contain only upper case
4485 letters, so output the names in upper case, though we actually recognize
4486 them in either case in the AUTH command. */
4490 && !sender_host_authenticated
4492 && verify_check_host(&auth_advertise_hosts) == OK
4496 for (auth_instance * au = auths; au; au = au->next)
4498 au->advertised = FALSE;
4501 DEBUG(D_auth+D_expand) debug_printf_indent(
4502 "Evaluating advertise_condition for %s %s athenticator\n",
4503 au->name, au->public_name);
4504 if ( !au->advertise_condition
4505 || expand_check_condition(au->advertise_condition, au->name,
4512 g = string_catn(g, smtp_code, 3);
4513 g = string_catn(g, US"-AUTH", 5);
4515 fl.auth_advertised = TRUE;
4518 g = string_catn(g, US" ", 1);
4519 g = string_cat (g, au->public_name);
4520 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4521 au->advertised = TRUE;
4526 if (!first) g = string_catn(g, US"\r\n", 2);
4529 /* RFC 3030 CHUNKING */
4531 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4533 g = string_catn(g, smtp_code, 3);
4534 g = string_catn(g, US"-CHUNKING\r\n", 11);
4535 f.chunking_offered = TRUE;
4536 chunking_state = CHUNKING_OFFERED;
4539 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4540 if it has been included in the binary, and the host matches
4541 tls_advertise_hosts. We must *not* advertise if we are already in a
4542 secure connection. */
4545 if (tls_in.active.sock < 0 &&
4546 verify_check_host(&tls_advertise_hosts) != FAIL)
4548 g = string_catn(g, smtp_code, 3);
4549 g = string_catn(g, US"-STARTTLS\r\n", 11);
4550 fl.tls_advertised = TRUE;
4554 #ifndef DISABLE_PRDR
4555 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4558 g = string_catn(g, smtp_code, 3);
4559 g = string_catn(g, US"-PRDR\r\n", 7);
4564 if ( accept_8bitmime
4565 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4567 g = string_catn(g, smtp_code, 3);
4568 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4569 fl.smtputf8_advertised = TRUE;
4573 /* Finish off the multiline reply with one that is always available. */
4575 g = string_catn(g, smtp_code, 3);
4576 g = string_catn(g, US" HELP\r\n", 7);
4579 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4583 if (tls_in.active.sock >= 0)
4584 (void)tls_write(NULL, g->s, g->ptr,
4585 # ifndef DISABLE_PIPE_CONNECT
4586 fl.pipe_connect_acceptable && pipeline_connect_sends());
4592 (void) fwrite(g->s, 1, g->ptr, smtp_out);
4598 (void) string_from_gstring(g);
4599 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4600 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4601 debug_printf("SMTP>> %s", g->s);
4603 fl.helo_seen = TRUE;
4605 /* Reset the protocol and the state, abandoning any previous message. */
4607 (sender_host_address ? protocols : protocols_local)
4609 ? pextend + (sender_host_authenticated ? pauthed : 0)
4611 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4613 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4614 reset_point = smtp_reset(reset_point);
4616 break; /* HELO/EHLO */
4619 /* The MAIL command requires an address as an operand. All we do
4620 here is to parse it for syntactic correctness. The form "<>" is
4621 a special case which converts into an empty string. The start/end
4622 pointers in the original are not used further for this address, as
4623 it is the canonical extracted address which is all that is kept. */
4627 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4629 was_rej_mail = TRUE; /* Reset if accepted */
4630 env_mail_type_t * mail_args; /* Sanity check & validate args */
4633 if (fl.helo_required)
4635 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4636 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4637 "HELO/EHLO given", host_and_ident(FALSE));
4640 else if (mailmax < 0)
4641 mailmax = expand_mailmax(smtp_accept_max_per_connection);
4645 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4646 US"sender already given");
4650 if (!*smtp_cmd_data)
4652 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4653 US"MAIL must have an address operand");
4657 /* Check to see if the limit for messages per connection would be
4658 exceeded by accepting further messages. */
4660 if (mailmax > 0 && smtp_mailcmd_count > mailmax)
4662 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4663 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4664 "messages in one connection", host_and_ident(TRUE));
4668 /* Reset for start of message - even if this is going to fail, we
4669 obviously need to throw away any previous data. */
4671 cancel_cutthrough_connection(TRUE, US"MAIL received");
4672 reset_point = smtp_reset(reset_point);
4674 sender_data = recipient_data = NULL;
4676 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4678 if (fl.esmtp) for(;;)
4680 uschar *name, *value, *end;
4681 unsigned long int size;
4682 BOOL arg_error = FALSE;
4684 if (!extract_option(&name, &value)) break;
4686 for (mail_args = env_mail_type_list;
4687 mail_args->value != ENV_MAIL_OPT_NULL;
4690 if (strcmpic(name, mail_args->name) == 0)
4692 if (mail_args->need_value && strcmpic(value, US"") == 0)
4695 switch(mail_args->value)
4697 /* Handle SIZE= by reading the value. We don't do the check till later,
4698 in order to be able to log the sender address on failure. */
4699 case ENV_MAIL_OPT_SIZE:
4700 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4702 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4704 message_size = (int)size;
4710 /* If this session was initiated with EHLO and accept_8bitmime is set,
4711 Exim will have indicated that it supports the BODY=8BITMIME option. In
4712 fact, it does not support this according to the RFCs, in that it does not
4713 take any special action for forwarding messages containing 8-bit
4714 characters. That is why accept_8bitmime is not the default setting, but
4715 some sites want the action that is provided. We recognize both "8BITMIME"
4716 and "7BIT" as body types, but take no action. */
4717 case ENV_MAIL_OPT_BODY:
4718 if (accept_8bitmime) {
4719 if (strcmpic(value, US"8BITMIME") == 0)
4721 else if (strcmpic(value, US"7BIT") == 0)
4726 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4727 US"invalid data for BODY");
4730 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4736 /* Handle the two DSN options, but only if configured to do so (which
4737 will have caused "DSN" to be given in the EHLO response). The code itself
4738 is included only if configured in at build time. */
4740 case ENV_MAIL_OPT_RET:
4741 if (fl.dsn_advertised)
4743 /* Check if RET has already been set */
4746 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4747 US"RET can be specified once only");
4750 dsn_ret = strcmpic(value, US"HDRS") == 0
4752 : strcmpic(value, US"FULL") == 0
4755 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4756 /* Check for invalid invalid value, and exit with error */
4759 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4760 US"Value for RET is invalid");
4765 case ENV_MAIL_OPT_ENVID:
4766 if (fl.dsn_advertised)
4768 /* Check if the dsn envid has been already set */
4771 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4772 US"ENVID can be specified once only");
4775 dsn_envid = string_copy(value);
4776 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4780 /* Handle the AUTH extension. If the value given is not "<>" and either
4781 the ACL says "yes" or there is no ACL but the sending host is
4782 authenticated, we set it up as the authenticated sender. However, if the
4783 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4784 the condition is met. The value of AUTH is an xtext, which means that +,
4785 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4787 case ENV_MAIL_OPT_AUTH:
4788 if (Ustrcmp(value, "<>") != 0)
4793 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4795 /* Put back terminator overrides for error message */
4798 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4799 US"invalid data for AUTH");
4802 if (!acl_smtp_mailauth)
4804 ignore_msg = US"client not authenticated";
4805 rc = sender_host_authenticated ? OK : FAIL;
4809 ignore_msg = US"rejected by ACL";
4810 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4811 &user_msg, &log_msg);
4817 if (authenticated_by == NULL ||
4818 authenticated_by->mail_auth_condition == NULL ||
4819 expand_check_condition(authenticated_by->mail_auth_condition,
4820 authenticated_by->name, US"authenticator"))
4821 break; /* Accept the AUTH */
4823 ignore_msg = US"server_mail_auth_condition failed";
4824 if (authenticated_id != NULL)
4825 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4826 ignore_msg, authenticated_id);
4831 authenticated_sender = NULL;
4832 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4833 value, host_and_ident(TRUE), ignore_msg);
4836 /* Should only get DEFER or ERROR here. Put back terminator
4837 overrides for error message */
4842 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4849 #ifndef DISABLE_PRDR
4850 case ENV_MAIL_OPT_PRDR:
4852 prdr_requested = TRUE;
4857 case ENV_MAIL_OPT_UTF8:
4858 if (!fl.smtputf8_advertised)
4860 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4861 US"SMTPUTF8 used when not advertised");
4865 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4866 message_smtputf8 = allow_utf8_domains = TRUE;
4867 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4869 int old_pool = store_pool;
4870 store_pool = POOL_PERM;
4871 received_protocol = string_sprintf("utf8%s", received_protocol);
4872 store_pool = old_pool;
4877 /* No valid option. Stick back the terminator characters and break
4878 the loop. Do the name-terminator second as extract_option sets
4879 value==name when it found no equal-sign.
4880 An error for a malformed address will occur. */
4881 case ENV_MAIL_OPT_NULL:
4889 /* Break out of for loop if switch() had bad argument or
4890 when start of the email address is reached */
4891 if (arg_error) break;
4894 /* If we have passed the threshold for rate limiting, apply the current
4895 delay, and update it for next time, provided this is a limited host. */
4897 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4898 verify_check_host(&smtp_ratelimit_hosts) == OK)
4900 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4901 smtp_delay_mail/1000.0);
4902 millisleep((int)smtp_delay_mail);
4903 smtp_delay_mail *= smtp_rlm_factor;
4904 if (smtp_delay_mail > (double)smtp_rlm_limit)
4905 smtp_delay_mail = (double)smtp_rlm_limit;
4908 /* Now extract the address, first applying any SMTP-time rewriting. The
4909 TRUE flag allows "<>" as a sender address. */
4911 raw_sender = rewrite_existflags & rewrite_smtp
4912 /* deconst ok as smtp_cmd_data was not const */
4913 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4914 global_rewrite_rules)
4918 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4923 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4927 sender_address = raw_sender;
4929 /* If there is a configured size limit for mail, check that this message
4930 doesn't exceed it. The check is postponed to this point so that the sender
4933 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4935 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4936 log_write(L_size_reject,
4937 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4938 "message too big: size%s=%d max=%d",
4940 host_and_ident(TRUE),
4941 (message_size == INT_MAX)? ">" : "",
4943 thismessage_size_limit);
4944 sender_address = NULL;
4948 /* Check there is enough space on the disk unless configured not to.
4949 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4950 plus the current message - i.e. we accept the message only if it won't
4951 reduce the space below the threshold. Add 5000 to the size to allow for
4952 overheads such as the Received: line and storing of recipients, etc.
4953 By putting the check here, even when SIZE is not given, it allow VRFY
4954 and EXPN etc. to be used when space is short. */
4956 if (!receive_check_fs(
4957 smtp_check_spool_space && message_size >= 0
4958 ? message_size + 5000 : 0))
4960 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4961 sender_address = NULL;
4965 /* If sender_address is unqualified, reject it, unless this is a locally
4966 generated message, or the sending host or net is permitted to send
4967 unqualified addresses - typically local machines behaving as MUAs -
4968 in which case just qualify the address. The flag is set above at the start
4969 of the SMTP connection. */
4971 if (!sender_domain && *sender_address)
4972 if (f.allow_unqualified_sender)
4974 sender_domain = Ustrlen(sender_address) + 1;
4975 /* deconst ok as sender_address was not const */
4976 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4977 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4982 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4984 log_write(L_smtp_syntax_error,
4985 LOG_MAIN|LOG_REJECT,
4986 "unqualified sender rejected: <%s> %s%s",
4988 host_and_ident(TRUE),
4990 sender_address = NULL;
4994 /* Apply an ACL check if one is defined, before responding. Afterwards,
4995 when pipelining is not advertised, do another sync check in case the ACL
4996 delayed and the client started sending in the meantime. */
5000 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
5001 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
5007 if (rc == OK || rc == DISCARD)
5009 BOOL more = pipeline_response();
5012 smtp_printf("%s%s%s", more, US"250 OK",
5013 #ifndef DISABLE_PRDR
5014 prdr_requested ? US", PRDR Requested" : US"",
5021 #ifndef DISABLE_PRDR
5023 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5025 smtp_user_msg(US"250", user_msg);
5027 smtp_delay_rcpt = smtp_rlr_base;
5028 f.recipients_discarded = (rc == DISCARD);
5029 was_rej_mail = FALSE;
5033 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5034 sender_address = NULL;
5039 /* The RCPT command requires an address as an operand. There may be any
5040 number of RCPT commands, specifying multiple recipients. We build them all
5041 into a data structure. The start/end values given by parse_extract_address
5042 are not used, as we keep only the extracted address. */
5046 /* We got really to many recipients. A check against configured
5047 limits is done later */
5048 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5049 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5051 was_rcpt = fl.rcpt_in_progress = TRUE;
5053 /* There must be a sender address; if the sender was rejected and
5054 pipelining was advertised, we assume the client was pipelining, and do not
5055 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5056 get the same treatment. */
5058 if (sender_address == NULL)
5060 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5062 smtp_printf("503 sender not yet given\r\n", FALSE);
5063 was_rej_mail = TRUE;
5067 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5068 US"sender not yet given");
5069 was_rcpt = FALSE; /* Not a valid RCPT */
5075 /* Check for an operand */
5077 if (smtp_cmd_data[0] == 0)
5079 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5080 US"RCPT must have an address operand");
5085 /* Set the DSN flags orcpt and dsn_flags from the session*/
5089 if (fl.esmtp) for(;;)
5091 uschar *name, *value;
5093 if (!extract_option(&name, &value))
5096 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5098 /* Check whether orcpt has been already set */
5101 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5102 US"ORCPT can be specified once only");
5105 orcpt = string_copy(value);
5106 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5109 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5111 /* Check if the notify flags have been already set */
5114 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5115 US"NOTIFY can be specified once only");
5118 if (strcmpic(value, US"NEVER") == 0)
5119 dsn_flags |= rf_notify_never;
5126 while (*pp != 0 && *pp != ',') pp++;
5127 if (*pp == ',') *pp++ = 0;
5128 if (strcmpic(p, US"SUCCESS") == 0)
5130 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5131 dsn_flags |= rf_notify_success;
5133 else if (strcmpic(p, US"FAILURE") == 0)
5135 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5136 dsn_flags |= rf_notify_failure;
5138 else if (strcmpic(p, US"DELAY") == 0)
5140 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5141 dsn_flags |= rf_notify_delay;
5145 /* Catch any strange values */
5146 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5147 US"Invalid value for NOTIFY parameter");
5152 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5156 /* Unknown option. Stick back the terminator characters and break
5157 the loop. An error for a malformed address will occur. */
5161 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5168 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5169 as a recipient address */
5171 recipient = rewrite_existflags & rewrite_smtp
5172 /* deconst ok as smtp_cmd_data was not const */
5173 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5174 global_rewrite_rules)
5177 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5178 &recipient_domain, FALSE)))
5180 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5185 /* If the recipient address is unqualified, reject it, unless this is a
5186 locally generated message. However, unqualified addresses are permitted
5187 from a configured list of hosts and nets - typically when behaving as
5188 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5189 really. The flag is set at the start of the SMTP connection.
5191 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5192 assumed this meant "reserved local part", but the revision of RFC 821 and
5193 friends now makes it absolutely clear that it means *mailbox*. Consequently
5194 we must always qualify this address, regardless. */
5196 if (!recipient_domain)
5197 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5204 /* Check maximum allowed */
5206 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5208 if (recipients_max_reject)
5211 smtp_printf("552 too many recipients\r\n", FALSE);
5213 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5214 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5219 smtp_printf("452 too many recipients\r\n", FALSE);
5221 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5222 "temporarily rejected: sender=<%s> %s", sender_address,
5223 host_and_ident(TRUE));
5230 /* If we have passed the threshold for rate limiting, apply the current
5231 delay, and update it for next time, provided this is a limited host. */
5233 if (rcpt_count > smtp_rlr_threshold &&
5234 verify_check_host(&smtp_ratelimit_hosts) == OK)
5236 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5237 smtp_delay_rcpt/1000.0);
5238 millisleep((int)smtp_delay_rcpt);
5239 smtp_delay_rcpt *= smtp_rlr_factor;
5240 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5241 smtp_delay_rcpt = (double)smtp_rlr_limit;
5244 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5245 for them. Otherwise, check the access control list for this recipient. As
5246 there may be a delay in this, re-check for a synchronization error
5247 afterwards, unless pipelining was advertised. */
5249 if (f.recipients_discarded)
5252 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5254 && !f.smtp_in_pipelining_advertised && !check_sync())
5257 /* The ACL was happy */
5261 BOOL more = pipeline_response();
5264 smtp_user_msg(US"250", user_msg);
5266 smtp_printf("250 Accepted\r\n", more);
5267 receive_add_recipient(recipient, -1);
5269 /* Set the dsn flags in the recipients_list */
5270 recipients_list[recipients_count-1].orcpt = orcpt;
5271 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5273 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5274 recipients_list[recipients_count-1].orcpt,
5275 recipients_list[recipients_count-1].dsn_flags); */
5278 /* The recipient was discarded */
5280 else if (rc == DISCARD)
5283 smtp_user_msg(US"250", user_msg);
5285 smtp_printf("250 Accepted\r\n", FALSE);
5288 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5289 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5290 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5291 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5292 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5295 /* Either the ACL failed the address, or it was deferred. */
5299 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5300 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5305 /* The DATA command is legal only if it follows successful MAIL FROM
5306 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5307 not counted as a protocol error if it follows RCPT (which must have been
5308 rejected if there are no recipients.) This function is complete when a
5309 valid DATA command is encountered.
5311 Note concerning the code used: RFC 2821 says this:
5313 - If there was no MAIL, or no RCPT, command, or all such commands
5314 were rejected, the server MAY return a "command out of sequence"
5315 (503) or "no valid recipients" (554) reply in response to the
5318 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5319 because it is the same whether pipelining is in use or not.
5321 If all the RCPT commands that precede DATA provoked the same error message
5322 (often indicating some kind of system error), it is helpful to include it
5323 with the DATA rejection (an idea suggested by Tony Finch). */
5330 if (chunking_state != CHUNKING_OFFERED)
5332 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5333 US"BDAT command used when CHUNKING not advertised");
5337 /* grab size, endmarker */
5339 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5341 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5342 US"missing size for BDAT command");
5345 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5346 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5347 chunking_data_left = chunking_datasize;
5348 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5349 (int)chunking_state, chunking_data_left);
5351 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5360 f.bdat_readers_wanted = FALSE;
5362 DATA_BDAT: /* Common code for DATA and BDAT */
5363 #ifndef DISABLE_PIPE_CONNECT
5364 fl.pipe_connect_acceptable = FALSE;
5366 if (!discarded && recipients_count <= 0)
5368 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5370 uschar *code = US"503";
5371 int len = Ustrlen(rcpt_smtp_response);
5372 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5374 /* Responses from smtp_printf() will have \r\n on the end */
5375 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5376 rcpt_smtp_response[len-2] = 0;
5377 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5379 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5380 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5381 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5383 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5384 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5385 ? US"valid RCPT command must precede DATA"
5386 : US"valid RCPT command must precede BDAT");
5388 if (chunking_state > CHUNKING_OFFERED)
5390 bdat_push_receive_functions();
5396 if (toomany && recipients_max_reject)
5398 sender_address = NULL; /* This will allow a new MAIL without RSET */
5399 sender_address_unrewritten = NULL;
5400 smtp_printf("554 Too many recipients\r\n", FALSE);
5402 if (chunking_state > CHUNKING_OFFERED)
5404 bdat_push_receive_functions();
5410 if (chunking_state > CHUNKING_OFFERED)
5411 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5414 /* If there is an ACL, re-check the synchronization afterwards, since the
5415 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5416 to get the DATA command sent. */
5418 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5422 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5423 f.enable_dollar_recipients = TRUE;
5424 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5426 f.enable_dollar_recipients = FALSE;
5427 if (rc == OK && !check_sync())
5431 { /* Either the ACL failed the address, or it was deferred. */
5432 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5438 smtp_user_msg(US"354", user_msg);
5441 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5444 if (f.bdat_readers_wanted)
5445 bdat_push_receive_functions();
5448 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5449 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5450 US &on, sizeof(on));
5453 message_ended = END_NOTENDED; /* Indicate in middle of data */
5464 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5465 &start, &end, &recipient_domain, FALSE)))
5467 smtp_printf("501 %s\r\n", FALSE, errmess);
5471 if (!recipient_domain)
5472 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5476 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5477 &user_msg, &log_msg)) != OK)
5478 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5482 address_item * addr = deliver_make_addr(address, FALSE);
5484 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5485 -1, -1, NULL, NULL, NULL))
5488 s = string_sprintf("250 <%s> is deliverable", address);
5492 s = (addr->user_message != NULL)?
5493 string_sprintf("451 <%s> %s", address, addr->user_message) :
5494 string_sprintf("451 Cannot resolve <%s> at this time", address);
5498 s = (addr->user_message != NULL)?
5499 string_sprintf("550 <%s> %s", address, addr->user_message) :
5500 string_sprintf("550 <%s> is not deliverable", address);
5501 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5502 smtp_cmd_argument, host_and_ident(TRUE));
5506 smtp_printf("%s\r\n", FALSE, s);
5514 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5516 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5519 BOOL save_log_testing_mode = f.log_testing_mode;
5520 f.address_test_mode = f.log_testing_mode = TRUE;
5521 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5522 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5524 f.address_test_mode = FALSE;
5525 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5534 if (!fl.tls_advertised)
5536 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5537 US"STARTTLS command used when not advertised");
5541 /* Apply an ACL check if one is defined */
5543 if ( acl_smtp_starttls
5544 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5545 &user_msg, &log_msg)) != OK
5548 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5552 /* RFC 2487 is not clear on when this command may be sent, though it
5553 does state that all information previously obtained from the client
5554 must be discarded if a TLS session is started. It seems reasonable to
5555 do an implied RSET when STARTTLS is received. */
5557 incomplete_transaction_log(US"STARTTLS");
5558 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5559 reset_point = smtp_reset(reset_point);
5561 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5563 /* There's an attack where more data is read in past the STARTTLS command
5564 before TLS is negotiated, then assumed to be part of the secure session
5565 when used afterwards; we use segregated input buffers, so are not
5566 vulnerable, but we want to note when it happens and, for sheer paranoia,
5567 ensure that the buffer is "wiped".
5568 Pipelining sync checks will normally have protected us too, unless disabled
5569 by configuration. */
5571 if (receive_smtp_buffered())
5574 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5575 if (tls_in.active.sock < 0)
5576 smtp_inend = smtp_inptr = smtp_inbuffer;
5577 /* and if TLS is already active, tls_server_start() should fail */
5580 /* There is nothing we value in the input buffer and if TLS is successfully
5581 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5582 fresh content into it. The buffer contains arbitrary content from an
5583 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5584 It seems safest to just wipe away the content rather than leave it as a
5585 target to jump to. */
5587 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5589 /* Attempt to start up a TLS session, and if successful, discard all
5590 knowledge that was obtained previously. At least, that's what the RFC says,
5591 and that's what happens by default. However, in order to work round YAEB,
5592 there is an option to remember the esmtp state. Sigh.
5594 We must allow for an extra EHLO command and an extra AUTH command after
5595 STARTTLS that don't add to the nonmail command count. */
5598 if ((rc = tls_server_start(&s)) == OK)
5600 if (!tls_remember_esmtp)
5601 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5602 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5603 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5604 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5605 if (sender_helo_name)
5607 sender_helo_name = NULL;
5608 host_build_sender_fullhost(); /* Rebuild */
5609 set_process_info("handling incoming TLS connection from %s",
5610 host_and_ident(FALSE));
5613 (sender_host_address ? protocols : protocols_local)
5615 ? pextend + (sender_host_authenticated ? pauthed : 0)
5617 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5620 sender_host_auth_pubname = sender_host_authenticated = NULL;
5621 authenticated_id = NULL;
5622 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5623 DEBUG(D_tls) debug_printf("TLS active\n");
5624 break; /* Successful STARTTLS */
5627 (void) smtp_log_tls_fail(s);
5629 /* Some local configuration problem was discovered before actually trying
5630 to do a TLS handshake; give a temporary error. */
5634 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5638 /* Hard failure. Reject everything except QUIT or closed connection. One
5639 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5640 set, but we must still reject all incoming commands. Another is a handshake
5641 failure - and there may some encrypted data still in the pipe to us, which we
5642 see as garbage commands. */
5644 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5645 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5648 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5649 smtp_get_connection_info());
5650 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5654 /* It is perhaps arguable as to which exit ACL should be called here,
5655 but as it is probably a situation that almost never arises, it
5656 probably doesn't matter. We choose to call the real QUIT ACL, which in
5657 some sense is perhaps "right". */
5660 f.smtp_in_quit = TRUE;
5663 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5664 &log_msg)) == ERROR))
5665 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5668 smtp_respond(US"221", 3, TRUE, user_msg);
5670 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5671 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5672 smtp_get_connection_info());
5677 smtp_printf("554 Security failure\r\n", FALSE);
5680 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5685 /* The ACL for QUIT is provided for gathering statistical information or
5686 similar; it does not affect the response code, but it can supply a custom
5690 smtp_quit_handler(&user_msg, &log_msg);
5696 smtp_rset_handler();
5697 cancel_cutthrough_connection(TRUE, US"RSET received");
5698 reset_point = smtp_reset(reset_point);
5705 smtp_printf("250 OK\r\n", FALSE);
5709 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5710 used, a check will be done for permitted hosts. Show STARTTLS only if not
5711 already in a TLS session and if it would be advertised in the EHLO
5716 smtp_printf("214-Commands supported:\r\n", TRUE);
5720 Ustrcat(buffer, US" AUTH");
5722 if (tls_in.active.sock < 0 &&
5723 verify_check_host(&tls_advertise_hosts) != FAIL)
5724 Ustrcat(buffer, US" STARTTLS");
5726 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5727 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5728 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5729 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5730 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5731 smtp_printf("214%s\r\n", FALSE, buffer);
5737 incomplete_transaction_log(US"connection lost");
5738 smtp_notquit_exit(US"connection-lost", US"421",
5739 US"%s lost input connection", smtp_active_hostname);
5741 /* Don't log by default unless in the middle of a message, as some mailers
5742 just drop the call rather than sending QUIT, and it clutters up the logs.
5745 if (sender_address || recipients_count > 0)
5746 log_write(L_lost_incoming_connection, LOG_MAIN,
5747 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5748 f.sender_host_unknown ? "EOF" : "disconnection",
5749 f.tcp_in_fastopen_logged
5752 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5754 host_and_ident(FALSE), smtp_read_error,
5755 string_timesince(&smtp_connection_start)
5759 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5760 smtp_get_connection_info(),
5761 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5763 string_timesince(&smtp_connection_start)
5774 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5775 US"ETRN is not permitted inside a transaction");
5779 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5780 host_and_ident(FALSE));
5782 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5783 &user_msg, &log_msg)) != OK)
5785 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5789 /* Compute the serialization key for this command. */
5791 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5793 /* If a command has been specified for running as a result of ETRN, we
5794 permit any argument to ETRN. If not, only the # standard form is permitted,
5795 since that is strictly the only kind of ETRN that can be implemented
5796 according to the RFC. */
5798 if (smtp_etrn_command)
5802 etrn_command = smtp_etrn_command;
5803 deliver_domain = smtp_cmd_data;
5804 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5805 US"ETRN processing", &error);
5806 deliver_domain = NULL;
5809 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5811 smtp_printf("458 Internal failure\r\n", FALSE);
5816 /* Else set up to call Exim with the -R option. */
5820 if (*smtp_cmd_data++ != '#')
5822 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5823 US"argument must begin with #");
5826 etrn_command = US"exim -R";
5827 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5828 *queue_name ? 4 : 2,
5829 US"-R", smtp_cmd_data,
5830 US"-MCG", queue_name);
5833 /* If we are host-testing, don't actually do anything. */
5839 debug_printf("ETRN command is: %s\n", etrn_command);
5840 debug_printf("ETRN command execution skipped\n");
5842 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5843 else smtp_user_msg(US"250", user_msg);
5848 /* If ETRN queue runs are to be serialized, check the database to
5849 ensure one isn't already running. */
5851 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5853 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5857 /* Fork a child process and run the command. We don't want to have to
5858 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5859 forking. It should be set that way anyway for external incoming SMTP,
5860 but we save and restore to be tidy. If serialization is required, we
5861 actually run the command in yet another process, so we can wait for it
5862 to complete and then remove the serialization lock. */
5864 oldsignal = signal(SIGCHLD, SIG_IGN);
5866 if ((pid = exim_fork(US"etrn-command")) == 0)
5868 smtp_input = FALSE; /* This process is not associated with the */
5869 (void)fclose(smtp_in); /* SMTP call any more. */
5870 (void)fclose(smtp_out);
5872 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5874 /* If not serializing, do the exec right away. Otherwise, fork down
5875 into another process. */
5877 if ( !smtp_etrn_serialize
5878 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5880 DEBUG(D_exec) debug_print_argv(argv);
5881 exim_nullstd(); /* Ensure std{in,out,err} exist */
5882 execv(CS argv[0], (char *const *)argv);
5883 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5884 etrn_command, strerror(errno));
5885 _exit(EXIT_FAILURE); /* paranoia */
5888 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5889 is, we are in the first subprocess, after forking again. All we can do
5890 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5891 complete, before removing the serialization. */
5894 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5895 "failed: %s", strerror(errno));
5899 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5901 (void)wait(&status);
5902 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5906 enq_end(etrn_serialize_key);
5907 exim_underbar_exit(EXIT_SUCCESS);
5910 /* Back in the top level SMTP process. Check that we started a subprocess
5911 and restore the signal state. */
5915 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5917 smtp_printf("458 Unable to fork process\r\n", FALSE);
5918 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5922 smtp_printf("250 OK\r\n", FALSE);
5924 smtp_user_msg(US"250", user_msg);
5926 signal(SIGCHLD, oldsignal);
5931 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5932 US"unexpected argument data");
5936 /* This currently happens only for NULLs, but could be extended. */
5939 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5940 US"NUL character(s) present (shown as '?')");
5941 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5948 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5949 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5950 c = smtp_inend - smtp_inptr;
5951 if (c > 150) c = 150; /* limit logged amount */
5953 incomplete_transaction_log(US"sync failure");
5954 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5955 "(next input sent too soon: pipelining was%s advertised): "
5956 "rejected \"%s\" %s next input=\"%s\"",
5957 f.smtp_in_pipelining_advertised ? "" : " not",
5958 smtp_cmd_buffer, host_and_ident(TRUE),
5959 string_printing(smtp_inptr));
5960 smtp_notquit_exit(US"synchronization-error", US"554",
5961 US"SMTP synchronization error");
5962 done = 1; /* Pretend eof - drops connection */
5966 case TOO_MANY_NONMAIL_CMD:
5967 s = smtp_cmd_buffer;
5968 while (*s != 0 && !isspace(*s)) s++;
5969 incomplete_transaction_log(US"too many non-mail commands");
5970 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5971 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5972 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5973 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5974 done = 1; /* Pretend eof - drops connection */
5977 #ifdef SUPPORT_PROXY
5978 case PROXY_FAIL_IGNORE_CMD:
5979 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5984 if (unknown_command_count++ >= smtp_max_unknown_commands)
5986 log_write(L_smtp_syntax_error, LOG_MAIN,
5987 "SMTP syntax error in \"%s\" %s %s",
5988 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5989 US"unrecognized command");
5990 incomplete_transaction_log(US"unrecognized command");
5991 smtp_notquit_exit(US"bad-commands", US"500",
5992 US"Too many unrecognized commands");
5994 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5995 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5996 string_printing(smtp_cmd_buffer));
5999 done = synprot_error(L_smtp_syntax_error, 500, NULL,
6000 US"unrecognized command");
6004 /* This label is used by goto's inside loops that want to break out to
6005 the end of the command-processing loop. */
6008 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
6009 last_was_rcpt = was_rcpt; /* protocol error handling */
6013 return done - 2; /* Convert yield values */
6019 authres_smtpauth(gstring * g)
6021 if (!sender_host_authenticated)
6024 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
6026 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
6027 g = authenticated_id
6028 ? string_append(g, 2, US") x509.auth=", authenticated_id)
6029 : string_cat(g, US") reason=x509.auth");
6031 g = authenticated_id
6032 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
6033 : string_cat(g, US", no id saved)");
6035 if (authenticated_sender)
6036 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6044 /* End of smtp_in.c */