1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 uschar * smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Recheck synchronization *
324 *************************************************/
326 /* Synchronization checks can never be perfect because a packet may be on its
327 way but not arrived when the check is done. Normally, the checks happen when
328 commands are read: Exim ensures that there is no more input in the input buffer.
329 In normal cases, the response to the command will be fast, and there is no
332 However, for some commands an ACL is run, and that can include delays. In those
333 cases, it is useful to do another check on the input just before sending the
334 response. This also applies at the start of a connection. This function does
335 that check by means of the select() function, as long as the facility is not
336 disabled or inappropriate. A failure of select() is ignored.
338 When there is unwanted input, we read it so that it appears in the log of the
342 Returns: TRUE if all is well; FALSE if there is input pending
346 wouldblock_reading(void)
350 struct timeval tzero;
353 if (tls_in.active.sock >= 0)
354 return !tls_could_read();
357 if (smtp_inptr < smtp_inend)
360 fd = fileno(smtp_in);
365 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
367 if (rc <= 0) return TRUE; /* Not ready to read */
368 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
369 if (rc < 0) return TRUE; /* End of file or error */
378 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
381 return wouldblock_reading();
385 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
386 a reponse with the one following. */
389 pipeline_response(void)
391 if ( !smtp_enforce_sync || !sender_host_address
392 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
395 if (wouldblock_reading()) return FALSE;
396 f.smtp_in_pipelining_used = TRUE;
401 #ifndef DISABLE_PIPE_CONNECT
403 pipeline_connect_sends(void)
405 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
408 if (wouldblock_reading()) return FALSE;
409 f.smtp_in_early_pipe_used = TRUE;
414 /*************************************************
415 * Log incomplete transactions *
416 *************************************************/
418 /* This function is called after a transaction has been aborted by RSET, QUIT,
419 connection drops or other errors. It logs the envelope information received
420 so far in order to preserve address verification attempts.
422 Argument: string to indicate what aborted the transaction
427 incomplete_transaction_log(uschar *what)
429 if (!sender_address /* No transaction in progress */
430 || !LOGGING(smtp_incomplete_transaction))
433 /* Build list of recipients for logging */
435 if (recipients_count > 0)
437 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
438 for (int i = 0; i < recipients_count; i++)
439 raw_recipients[i] = recipients_list[i].address;
440 raw_recipients_count = recipients_count;
443 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
444 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
451 smtp_command_timeout_exit(void)
453 log_write(L_lost_incoming_connection,
454 LOG_MAIN, "SMTP command timeout on%s connection from %s",
455 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
456 if (smtp_batched_input)
457 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
458 smtp_notquit_exit(US"command-timeout", US"421",
459 US"%s: SMTP command timeout - closing connection",
460 smtp_active_hostname);
461 exim_exit(EXIT_FAILURE);
465 smtp_command_sigterm_exit(void)
467 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
468 if (smtp_batched_input)
469 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
470 smtp_notquit_exit(US"signal-exit", US"421",
471 US"%s: Service not available - closing connection", smtp_active_hostname);
472 exim_exit(EXIT_FAILURE);
476 smtp_data_timeout_exit(void)
478 log_write(L_lost_incoming_connection,
479 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
480 sender_fullhost ? sender_fullhost : US"local process", sender_address);
481 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
482 /* Does not return */
486 smtp_data_sigint_exit(void)
488 log_write(0, LOG_MAIN, "%s closed after %s",
489 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
490 receive_bomb_out(US"signal-exit",
491 US"Service not available - SIGTERM or SIGINT received");
492 /* Does not return */
497 /* Refill the buffer, and notify DKIM verification code.
498 Return false for error or EOF.
502 smtp_refill(unsigned lim)
505 if (!smtp_out) return FALSE;
507 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
509 /* Limit amount read, so non-message data is not fed to DKIM.
510 Take care to not touch the safety NUL at the end of the buffer. */
512 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
514 if (smtp_receive_timeout > 0) ALARM_CLR(0);
517 /* Must put the error text in fixed store, because this might be during
518 header reading, where it releases unused store above the header. */
521 if (had_command_timeout) /* set by signal handler */
522 smtp_command_timeout_exit(); /* does not return */
523 if (had_command_sigterm)
524 smtp_command_sigterm_exit();
525 if (had_data_timeout)
526 smtp_data_timeout_exit();
528 smtp_data_sigint_exit();
530 smtp_had_error = save_errno;
531 smtp_read_error = string_copy_perm(
532 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
539 dkim_exim_verify_feed(smtp_inbuffer, rc);
541 smtp_inend = smtp_inbuffer + rc;
542 smtp_inptr = smtp_inbuffer;
546 /*************************************************
547 * SMTP version of getc() *
548 *************************************************/
550 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
551 it flushes the output, and refills the buffer, with a timeout. The signal
552 handler is set appropriately by the calling function. This function is not used
553 after a connection has negotiated itself into an TLS/SSL state.
555 Arguments: lim Maximum amount to read/buffer
556 Returns: the next character or EOF
560 smtp_getc(unsigned lim)
562 if (smtp_inptr >= smtp_inend)
563 if (!smtp_refill(lim))
565 return *smtp_inptr++;
569 smtp_getbuf(unsigned * len)
574 if (smtp_inptr >= smtp_inend)
575 if (!smtp_refill(*len))
576 { *len = 0; return NULL; }
578 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
589 int n = smtp_inend - smtp_inptr;
591 dkim_exim_verify_feed(smtp_inptr, n);
596 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
597 previous BDAT chunk and getting new ones when we run out. Uses the
598 underlying smtp_getc or tls_getc both for that and for getting the
599 (buffered) data byte. EOD signals (an expected) no further data.
600 ERR signals a protocol error, and EOF a closed input stream.
602 Called from read_bdat_smtp() in receive.c for the message body, but also
603 by the headers read loop in receive_msg(); manipulates chunking_state
604 to handle the BDAT command/response.
605 Placed here due to the correlation with the above smtp_getc(), which it wraps,
606 and also by the need to do smtp command/response handling.
608 Arguments: lim (ignored)
609 Returns: the next character or ERR, EOD or EOF
613 bdat_getc(unsigned lim)
615 uschar * user_msg = NULL;
624 if (chunking_data_left > 0)
625 return lwr_receive_getc(chunking_data_left--);
627 receive_getc = lwr_receive_getc;
628 receive_getbuf = lwr_receive_getbuf;
629 receive_ungetc = lwr_receive_ungetc;
631 dkim_save = dkim_collect_input;
632 dkim_collect_input = 0;
635 /* Unless PIPELINING was offered, there should be no next command
636 until after we ack that chunk */
638 if (!f.smtp_in_pipelining_advertised && !check_sync())
640 unsigned n = smtp_inend - smtp_inptr;
643 incomplete_transaction_log(US"sync failure");
644 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
645 "(next input sent too soon: pipelining was not advertised): "
646 "rejected \"%s\" %s next input=\"%s\"%s",
647 smtp_cmd_buffer, host_and_ident(TRUE),
648 string_printing(string_copyn(smtp_inptr, n)),
649 smtp_inend - smtp_inptr > n ? "..." : "");
650 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
651 US"SMTP synchronization error");
652 goto repeat_until_rset;
655 /* If not the last, ack the received chunk. The last response is delayed
656 until after the data ACL decides on it */
658 if (chunking_state == CHUNKING_LAST)
661 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
666 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
667 chunking_state = CHUNKING_OFFERED;
668 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
670 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
671 QUIT, RSET or NOOP but handling them seems obvious */
674 switch(smtp_read_command(TRUE, 1))
677 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
678 US"only BDAT permissible after non-LAST BDAT");
681 switch(smtp_read_command(TRUE, 1))
683 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
684 case EOF_CMD: return EOF;
685 case RSET_CMD: smtp_rset_handler(); return ERR;
686 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
687 US"only RSET accepted now") > 0)
689 goto repeat_until_rset;
693 smtp_quit_handler(&user_msg, &log_msg);
704 smtp_printf("250 OK\r\n", FALSE);
711 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
713 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
714 US"missing size for BDAT command");
717 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
718 ? CHUNKING_LAST : CHUNKING_ACTIVE;
719 chunking_data_left = chunking_datasize;
720 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
721 (int)chunking_state, chunking_data_left);
723 if (chunking_datasize == 0)
724 if (chunking_state == CHUNKING_LAST)
728 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
729 US"zero size for BDAT command");
730 goto repeat_until_rset;
733 receive_getc = bdat_getc;
734 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
735 receive_ungetc = bdat_ungetc;
737 dkim_collect_input = dkim_save;
739 break; /* to top of main loop */
746 bdat_getbuf(unsigned * len)
750 if (chunking_data_left <= 0)
751 { *len = 0; return NULL; }
753 if (*len > chunking_data_left) *len = chunking_data_left;
754 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
755 chunking_data_left -= *len;
760 bdat_flush_data(void)
762 while (chunking_data_left)
764 unsigned n = chunking_data_left;
765 if (!bdat_getbuf(&n)) break;
768 receive_getc = lwr_receive_getc;
769 receive_getbuf = lwr_receive_getbuf;
770 receive_ungetc = lwr_receive_ungetc;
772 if (chunking_state != CHUNKING_LAST)
774 chunking_state = CHUNKING_OFFERED;
775 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
782 /*************************************************
783 * SMTP version of ungetc() *
784 *************************************************/
786 /* Puts a character back in the input buffer. Only ever
792 Returns: the character
806 chunking_data_left++;
807 return lwr_receive_ungetc(ch);
812 /*************************************************
813 * SMTP version of feof() *
814 *************************************************/
816 /* Tests for a previous EOF
819 Returns: non-zero if the eof flag is set
831 /*************************************************
832 * SMTP version of ferror() *
833 *************************************************/
835 /* Tests for a previous read error, and returns with errno
836 restored to what it was when the error was detected.
839 Returns: non-zero if the error flag is set
845 errno = smtp_had_error;
846 return smtp_had_error;
851 /*************************************************
852 * Test for characters in the SMTP buffer *
853 *************************************************/
855 /* Used at the end of a message
864 return smtp_inptr < smtp_inend;
869 /*************************************************
870 * Write formatted string to SMTP channel *
871 *************************************************/
873 /* This is a separate function so that we don't have to repeat everything for
874 TLS support or debugging. It is global so that the daemon and the
875 authentication functions can use it. It does not return any error indication,
876 because major problems such as dropped connections won't show up till an output
877 flush for non-TLS connections. The smtp_fflush() function is available for
878 checking that: for convenience, TLS output errors are remembered here so that
879 they are also picked up later by smtp_fflush().
881 This function is exposed to the local_scan API; do not change the signature.
885 more further data expected
886 ... optional arguments
892 smtp_printf(const char *format, BOOL more, ...)
897 smtp_vprintf(format, more, ap);
901 /* This is split off so that verify.c:respond_printf() can, in effect, call
902 smtp_printf(), bearing in mind that in C a vararg function can't directly
903 call another vararg function, only a function which accepts a va_list.
905 This function is exposed to the local_scan API; do not change the signature.
907 /*XXX consider passing caller-info in, for string_vformat-onward */
910 smtp_vprintf(const char *format, BOOL more, va_list ap)
912 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
915 /* Use taint-unchecked routines for writing into big_buffer, trusting
916 that we'll never expand it. */
918 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
919 string_from_gstring(&gs);
923 uschar *msg_copy, *cr, *end;
924 msg_copy = string_copy(gs.s);
925 end = msg_copy + gs.ptr;
926 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
927 memmove(cr, cr + 1, (end--) - cr);
928 debug_printf("SMTP>> %s", msg_copy);
933 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
934 smtp_closedown(US"Unexpected error");
935 exim_exit(EXIT_FAILURE);
938 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
939 have had the same. Note: this code is also present in smtp_respond(). It would
940 be tidier to have it only in one place, but when it was added, it was easier to
941 do it that way, so as not to have to mess with the code for the RCPT command,
942 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
944 if (fl.rcpt_in_progress)
946 if (rcpt_smtp_response == NULL)
947 rcpt_smtp_response = string_copy(big_buffer);
948 else if (fl.rcpt_smtp_response_same &&
949 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
950 fl.rcpt_smtp_response_same = FALSE;
951 fl.rcpt_in_progress = FALSE;
954 /* Now write the string */
958 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
960 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
962 smtp_write_error = -1;
967 /*************************************************
968 * Flush SMTP out and check for error *
969 *************************************************/
971 /* This function isn't currently used within Exim (it detects errors when it
972 tries to read the next SMTP input), but is available for use in local_scan().
973 It flushes the output and checks for errors.
976 Returns: 0 for no error; -1 after an error
982 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
986 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
988 (fflush(smtp_out) != 0)
990 smtp_write_error = -1;
992 return smtp_write_error;
997 /*************************************************
998 * SMTP command read timeout *
999 *************************************************/
1001 /* Signal handler for timing out incoming SMTP commands. This attempts to
1004 Argument: signal number (SIGALRM)
1009 command_timeout_handler(int sig)
1011 had_command_timeout = sig;
1016 /*************************************************
1017 * SIGTERM received *
1018 *************************************************/
1020 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1022 Argument: signal number (SIGTERM)
1027 command_sigterm_handler(int sig)
1029 had_command_sigterm = sig;
1035 #ifdef SUPPORT_PROXY
1036 /*************************************************
1037 * Check if host is required proxy host *
1038 *************************************************/
1039 /* The function determines if inbound host will be a regular smtp host
1040 or if it is configured that it must use Proxy Protocol. A local
1048 check_proxy_protocol_host()
1052 if ( sender_host_address
1053 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1054 sender_host_address, NULL)) == OK)
1057 debug_printf("Detected proxy protocol configured host\n");
1058 proxy_session = TRUE;
1060 return proxy_session;
1064 /*************************************************
1065 * Read data until newline or end of buffer *
1066 *************************************************/
1067 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1068 read an entire buffer and assume there will be nothing past a proxy protocol
1069 header. Our approach normally is to use stdio, but again that relies upon
1070 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1071 reading _nothing_ before client TLS handshake. So we don't want to use the
1072 usual buffering reads which may read enough to block TLS starting.
1074 So unfortunately we're down to "read one byte at a time, with a syscall each,
1075 and expect a little overhead", for all proxy-opened connections which are v1,
1076 just to handle the TLS-on-connect case. Since SSL functions wrap the
1077 underlying fd, we can't assume that we can feed them any already-read content.
1079 We need to know where to read to, the max capacity, and we'll read until we
1080 get a CR and one more character. Let the caller scream if it's CR+!LF.
1082 Return the amount read.
1086 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1088 uschar *to = base + already;
1094 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1095 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1097 cr = memchr(base, '\r', already);
1100 if ((cr - base) < already - 1)
1102 /* \r and presumed \n already within what we have; probably not
1103 actually proxy protocol, but abort cleanly. */
1106 /* \r is last character read, just need one more. */
1110 while (capacity > 0)
1112 do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
1124 /* reached end without having room for a final newline, abort */
1129 /*************************************************
1130 * Setup host for proxy protocol *
1131 *************************************************/
1132 /* The function configures the connection based on a header from the
1133 inbound host to use Proxy Protocol. The specification is very exact
1134 so exit with an error if do not find the exact required pieces. This
1135 includes an incorrect number of spaces separating args.
1138 Returns: Boolean success
1142 setup_proxy_protocol_host()
1154 struct { /* TCP/UDP over IPv4, len = 12 */
1160 struct { /* TCP/UDP over IPv6, len = 36 */
1161 uint8_t src_addr[16];
1162 uint8_t dst_addr[16];
1166 struct { /* AF_UNIX sockets, len = 216 */
1167 uschar src_addr[108];
1168 uschar dst_addr[108];
1174 /* Temp variables used in PPv2 address:port parsing */
1176 char tmpip[INET_ADDRSTRLEN];
1177 struct sockaddr_in tmpaddr;
1178 char tmpip6[INET6_ADDRSTRLEN];
1179 struct sockaddr_in6 tmpaddr6;
1181 /* We can't read "all data until end" because while SMTP is
1182 server-speaks-first, the TLS handshake is client-speaks-first, so for
1183 TLS-on-connect ports the proxy protocol header will usually be immediately
1184 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1185 reinject data for reading by those. So instead we first read "enough to be
1186 safely read within the header, and figure out how much more to read".
1187 For v1 we will later read to the end-of-line, for v2 we will read based upon
1190 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1191 data is needed total. For v1, where the line looks like:
1192 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1194 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1195 We seem to support that. So, if we read 14 octets then we can tell if we're
1196 v2 or v1. If we're v1, we can continue reading as normal.
1198 If we're v2, we can't slurp up the entire header. We need the length in the
1199 15th & 16th octets, then to read everything after that.
1201 So to safely handle v1 and v2, with client-sent-first supported correctly,
1202 we have to do a minimum of 3 read calls, not 1. Eww.
1205 #define PROXY_INITIAL_READ 14
1206 #define PROXY_V2_HEADER_SIZE 16
1207 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1208 # error Code bug in sizes of data to read for proxy usage
1213 int fd = fileno(smtp_in);
1214 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1215 uschar * iptype; /* To display debug info */
1217 struct timeval tvtmp;
1218 socklen_t vslen = sizeof(struct timeval);
1221 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1222 ALARM(proxy_protocol_timeout);
1226 /* The inbound host was declared to be a Proxy Protocol host, so
1227 don't do a PEEK into the data, actually slurp up enough to be
1228 "safe". Can't take it all because TLS-on-connect clients follow
1229 immediately with TLS handshake. */
1230 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1232 while (ret == -1 && errno == EINTR && !had_command_timeout);
1237 /* For v2, handle reading the length, and then the rest. */
1238 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1243 /* First get the length fields. */
1246 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1247 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1252 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1254 /* May 2014: haproxy combined the version and command into one byte to
1255 allow two full bytes for the length field in order to proxy SSL
1256 connections. SSL Proxy is not supported in this version of Exim, but
1257 must still separate values here. */
1261 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1265 /* The v2 header will always be 16 bytes per the spec. */
1266 size = 16 + ntohs(hdr.v2.len);
1267 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1268 size, (int)sizeof(hdr));
1270 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1271 amount that we need. Double-check that the size is not unreasonable, then
1273 if (size > sizeof(hdr))
1275 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1283 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1284 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1288 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1289 } while (ret < size);
1291 } /* end scope for getting rest of data for v2 */
1293 /* At this point: if PROXYv2, we've read the exact size required for all data;
1294 if PROXYv1 then we've read "less than required for any valid line" and should
1297 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1299 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1303 case 0x01: /* PROXY command */
1306 case 0x11: /* TCPv4 address type */
1308 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1309 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1310 if (!string_is_ip_address(US tmpip, NULL))
1312 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1315 proxy_local_address = sender_host_address;
1316 sender_host_address = string_copy(US tmpip);
1317 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1318 proxy_local_port = sender_host_port;
1319 sender_host_port = tmpport;
1320 /* Save dest ip/port */
1321 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1322 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1323 if (!string_is_ip_address(US tmpip, NULL))
1325 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1328 proxy_external_address = string_copy(US tmpip);
1329 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1330 proxy_external_port = tmpport;
1332 case 0x21: /* TCPv6 address type */
1334 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1335 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1336 if (!string_is_ip_address(US tmpip6, NULL))
1338 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1341 proxy_local_address = sender_host_address;
1342 sender_host_address = string_copy(US tmpip6);
1343 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1344 proxy_local_port = sender_host_port;
1345 sender_host_port = tmpport;
1346 /* Save dest ip/port */
1347 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1348 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1349 if (!string_is_ip_address(US tmpip6, NULL))
1351 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1354 proxy_external_address = string_copy(US tmpip6);
1355 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1356 proxy_external_port = tmpport;
1360 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1364 /* Unsupported protocol, keep local connection address */
1366 case 0x00: /* LOCAL command */
1367 /* Keep local connection address for LOCAL */
1372 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1376 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1380 uschar *sp; /* Utility variables follow */
1385 /* get the rest of the line */
1386 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1391 p = string_copy(hdr.v1.line);
1392 end = memchr(p, '\r', ret - 1);
1394 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1396 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1399 *end = '\0'; /* Terminate the string */
1400 size = end + 2 - p; /* Skip header + CRLF */
1401 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1402 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1403 /* Step through the string looking for the required fields. Ensure
1404 strict adherence to required formatting, exit for any error. */
1406 if (!isspace(*(p++)))
1408 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1411 if (!Ustrncmp(p, CCS"TCP4", 4))
1413 else if (!Ustrncmp(p,CCS"TCP6", 4))
1415 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1417 iptype = US"Unknown";
1422 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1426 p += Ustrlen(iptype);
1427 if (!isspace(*(p++)))
1429 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1432 /* Find the end of the arg */
1433 if ((sp = Ustrchr(p, ' ')) == NULL)
1436 debug_printf("Did not find proxied src %s\n", iptype);
1440 if(!string_is_ip_address(p, NULL))
1443 debug_printf("Proxied src arg is not an %s address\n", iptype);
1446 proxy_local_address = sender_host_address;
1447 sender_host_address = p;
1449 if ((sp = Ustrchr(p, ' ')) == NULL)
1452 debug_printf("Did not find proxy dest %s\n", iptype);
1456 if(!string_is_ip_address(p, NULL))
1459 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1462 proxy_external_address = p;
1464 if ((sp = Ustrchr(p, ' ')) == NULL)
1466 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1470 tmp_port = strtol(CCS p, &endc, 10);
1471 if (*endc || tmp_port == 0)
1474 debug_printf("Proxied src port '%s' not an integer\n", p);
1477 proxy_local_port = sender_host_port;
1478 sender_host_port = tmp_port;
1480 if ((sp = Ustrchr(p, '\0')) == NULL)
1482 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1485 tmp_port = strtol(CCS p, &endc, 10);
1486 if (*endc || tmp_port == 0)
1489 debug_printf("Proxy dest port '%s' not an integer\n", p);
1492 proxy_external_port = tmp_port;
1493 /* Already checked for /r /n above. Good V1 header received. */
1497 /* Wrong protocol */
1498 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1499 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1505 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1506 yield = proxy_session;
1508 /* Don't flush any potential buffer contents. Any input on proxyfail
1509 should cause a synchronization failure */
1512 DEBUG(D_receive) if (had_command_timeout)
1513 debug_printf("Timeout while reading proxy header\n");
1518 sender_host_name = NULL;
1519 (void) host_name_lookup();
1520 host_build_sender_fullhost();
1524 f.proxy_session_failed = TRUE;
1526 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1534 /*************************************************
1535 * Read one command line *
1536 *************************************************/
1538 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1539 There are sites that don't do this, and in any case internal SMTP probably
1540 should check only for LF. Consequently, we check here for LF only. The line
1541 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1542 an unknown command. The command is read into the global smtp_cmd_buffer so that
1543 it is available via $smtp_command.
1545 The character reading routine sets up a timeout for each block actually read
1546 from the input (which may contain more than one command). We set up a special
1547 signal handler that closes down the session on a timeout. Control does not
1548 return when it runs.
1551 check_sync if TRUE, check synchronization rules if global option is TRUE
1552 buffer_lim maximum to buffer in lower layer
1554 Returns: a code identifying the command (enumerated above)
1558 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1562 BOOL hadnull = FALSE;
1564 had_command_timeout = 0;
1565 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1567 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1569 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1571 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1579 smtp_cmd_buffer[ptr++] = c;
1582 receive_linecount++; /* For BSMTP errors */
1583 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1585 /* If hit end of file, return pseudo EOF command. Whether we have a
1586 part-line already read doesn't matter, since this is an error state. */
1588 if (c == EOF) return EOF_CMD;
1590 /* Remove any CR and white space at the end of the line, and terminate the
1593 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1594 smtp_cmd_buffer[ptr] = 0;
1596 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1598 /* NULLs are not allowed in SMTP commands */
1600 if (hadnull) return BADCHAR_CMD;
1602 /* Scan command list and return identity, having set the data pointer
1603 to the start of the actual data characters. Check for SMTP synchronization
1606 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1608 #ifdef SUPPORT_PROXY
1609 /* Only allow QUIT command if Proxy Protocol parsing failed */
1610 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1614 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1615 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1616 || smtp_cmd_buffer[p->len] == 0
1617 || smtp_cmd_buffer[p->len] == ' '
1620 if (smtp_inptr < smtp_inend && /* Outstanding input */
1621 p->cmd < sync_cmd_limit && /* Command should sync */
1622 check_sync && /* Local flag set */
1623 smtp_enforce_sync && /* Global flag set */
1624 sender_host_address != NULL && /* Not local input */
1625 !f.sender_host_notsocket) /* Really is a socket */
1628 /* The variables $smtp_command and $smtp_command_argument point into the
1629 unmodified input buffer. A copy of the latter is taken for actual
1630 processing, so that it can be chopped up into separate parts if necessary,
1631 for example, when processing a MAIL command options such as SIZE that can
1632 follow the sender address. */
1634 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1635 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1636 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1637 smtp_cmd_data = smtp_data_buffer;
1639 /* Count non-mail commands from those hosts that are controlled in this
1640 way. The default is all hosts. We don't waste effort checking the list
1641 until we get a non-mail command, but then cache the result to save checking
1642 again. If there's a DEFER while checking the host, assume it's in the list.
1644 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1645 start of each incoming message by fiddling with the value in the table. */
1647 if (!p->is_mail_cmd)
1649 if (count_nonmail == TRUE_UNSET) count_nonmail =
1650 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1651 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1652 return TOO_MANY_NONMAIL_CMD;
1655 /* If there is data for a command that does not expect it, generate the
1658 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1662 #ifdef SUPPORT_PROXY
1663 /* Only allow QUIT command if Proxy Protocol parsing failed */
1664 if (proxy_session && f.proxy_session_failed)
1665 return PROXY_FAIL_IGNORE_CMD;
1668 /* Enforce synchronization for unknown commands */
1670 if ( smtp_inptr < smtp_inend /* Outstanding input */
1671 && check_sync /* Local flag set */
1672 && smtp_enforce_sync /* Global flag set */
1673 && sender_host_address /* Not local input */
1674 && !f.sender_host_notsocket) /* Really is a socket */
1682 /*************************************************
1683 * Forced closedown of call *
1684 *************************************************/
1686 /* This function is called from log.c when Exim is dying because of a serious
1687 disaster, and also from some other places. If an incoming non-batched SMTP
1688 channel is open, it swallows the rest of the incoming message if in the DATA
1689 phase, sends the reply string, and gives an error to all subsequent commands
1690 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1694 message SMTP reply string to send, excluding the code
1700 smtp_closedown(uschar *message)
1702 if (!smtp_in || smtp_batched_input) return;
1703 receive_swallow_smtp();
1704 smtp_printf("421 %s\r\n", FALSE, message);
1706 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1712 f.smtp_in_quit = TRUE;
1713 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1718 smtp_printf("250 Reset OK\r\n", FALSE);
1722 smtp_printf("421 %s\r\n", FALSE, message);
1730 /*************************************************
1731 * Set up connection info for logging *
1732 *************************************************/
1734 /* This function is called when logging information about an SMTP connection.
1735 It sets up appropriate source information, depending on the type of connection.
1736 If sender_fullhost is NULL, we are at a very early stage of the connection;
1737 just use the IP address.
1740 Returns: a string describing the connection
1744 smtp_get_connection_info(void)
1746 const uschar * hostname = sender_fullhost
1747 ? sender_fullhost : sender_host_address;
1750 return string_sprintf("SMTP connection from %s", hostname);
1752 if (f.sender_host_unknown || f.sender_host_notsocket)
1753 return string_sprintf("SMTP connection from %s", sender_ident);
1756 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1758 if (LOGGING(incoming_interface) && interface_address)
1759 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1760 interface_address, interface_port);
1762 return string_sprintf("SMTP connection from %s", hostname);
1768 /* Append TLS-related information to a log line
1771 g String under construction: allocated string to extend, or NULL
1773 Returns: Allocated string or NULL
1776 s_tlslog(gstring * g)
1778 if (LOGGING(tls_cipher) && tls_in.cipher)
1780 g = string_append(g, 2, US" X=", tls_in.cipher);
1781 #ifndef DISABLE_TLS_RESUME
1782 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1783 g = string_catn(g, US"*", 1);
1786 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1787 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1788 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1789 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1790 if (LOGGING(tls_sni) && tls_in.sni)
1791 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1799 s_connhad_log(gstring * g)
1801 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1802 ? US" C=..." : US" C=";
1804 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1805 if (smtp_connection_had[i] != SCH_NONE)
1807 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1810 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1811 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1816 /*************************************************
1817 * Log lack of MAIL if so configured *
1818 *************************************************/
1820 /* This function is called when an SMTP session ends. If the log selector
1821 smtp_no_mail is set, write a log line giving some details of what has happened
1822 in the SMTP session.
1829 smtp_log_no_mail(void)
1834 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1837 if (sender_host_authenticated)
1839 g = string_append(g, 2, US" A=", sender_host_authenticated);
1840 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1847 g = s_connhad_log(g);
1849 if (!(s = string_from_gstring(g))) s = US"";
1851 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1852 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1853 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1857 /* Return list of recent smtp commands */
1862 gstring * list = NULL;
1865 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1866 if (smtp_connection_had[i] != SCH_NONE)
1867 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1869 for (int i = 0; i < smtp_ch_index; i++)
1870 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1872 s = string_from_gstring(list);
1873 return s ? s : US"";
1879 /*************************************************
1880 * Check HELO line and set sender_helo_name *
1881 *************************************************/
1883 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1884 the domain name of the sending host, or an ip literal in square brackets. The
1885 argument is placed in sender_helo_name, which is in malloc store, because it
1886 must persist over multiple incoming messages. If helo_accept_junk is set, this
1887 host is permitted to send any old junk (needed for some broken hosts).
1888 Otherwise, helo_allow_chars can be used for rogue characters in general
1889 (typically people want to let in underscores).
1892 s the data portion of the line (already past any white space)
1894 Returns: TRUE or FALSE
1898 check_helo(uschar *s)
1901 uschar *end = s + Ustrlen(s);
1902 BOOL yield = fl.helo_accept_junk;
1904 /* Discard any previous helo name */
1906 sender_helo_name = NULL;
1908 /* Skip tests if junk is permitted. */
1912 /* Allow the new standard form for IPv6 address literals, namely,
1913 [IPv6:....], and because someone is bound to use it, allow an equivalent
1914 IPv4 form. Allow plain addresses as well. */
1921 if (strncmpic(s, US"[IPv6:", 6) == 0)
1922 yield = (string_is_ip_address(s+6, NULL) == 6);
1923 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1924 yield = (string_is_ip_address(s+6, NULL) == 4);
1926 yield = (string_is_ip_address(s+1, NULL) != 0);
1931 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1932 that have been configured (usually underscore - sigh). */
1935 for (yield = TRUE; *s; s++)
1936 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1937 Ustrchr(helo_allow_chars, *s) == NULL)
1943 /* Save argument if OK */
1945 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1953 /*************************************************
1954 * Extract SMTP command option *
1955 *************************************************/
1957 /* This function picks the next option setting off the end of smtp_cmd_data. It
1958 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1959 things that can appear there.
1962 name point this at the name
1963 value point this at the data string
1965 Returns: TRUE if found an option
1969 extract_option(uschar **name, uschar **value)
1972 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1973 while (isspace(*v)) v--;
1975 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1977 /* Take care to not stop at a space embedded in a quoted local-part */
1979 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1986 while(isalpha(n[-1])) n--;
1987 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1988 if (!isspace(n[-1])) return FALSE;
1994 if (v == smtp_cmd_data) return FALSE;
2006 /*************************************************
2007 * Reset for new message *
2008 *************************************************/
2010 /* This function is called whenever the SMTP session is reset from
2011 within either of the setup functions; also from the daemon loop.
2013 Argument: the stacking pool storage reset point
2018 smtp_reset(void *reset_point)
2020 recipients_list = NULL;
2021 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2022 raw_recipients_count = recipients_count = recipients_list_max = 0;
2023 message_linecount = 0;
2025 message_body = message_body_end = NULL;
2026 acl_added_headers = NULL;
2027 acl_removed_headers = NULL;
2028 f.queue_only_policy = FALSE;
2029 rcpt_smtp_response = NULL;
2030 fl.rcpt_smtp_response_same = TRUE;
2031 fl.rcpt_in_progress = FALSE;
2032 f.deliver_freeze = FALSE; /* Can be set by ACL */
2033 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2034 fake_response = OK; /* Can be set by ACL */
2035 #ifdef WITH_CONTENT_SCAN
2036 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2038 f.submission_mode = FALSE; /* Can be set by ACL */
2039 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2040 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2041 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2042 sending_ip_address = NULL;
2043 return_path = sender_address = NULL;
2044 deliver_localpart_data = deliver_domain_data =
2045 recipient_data = sender_data = NULL; /* Can be set by ACL */
2046 recipient_verify_failure = NULL;
2047 deliver_localpart_parent = deliver_localpart_orig = NULL;
2048 deliver_domain_parent = deliver_domain_orig = NULL;
2049 callout_address = NULL;
2050 submission_name = NULL; /* Can be set by ACL */
2051 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2052 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2053 sender_verified_list = NULL; /* No senders verified */
2054 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2055 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2057 authenticated_sender = NULL;
2058 #ifdef EXPERIMENTAL_BRIGHTMAIL
2060 bmi_verdicts = NULL;
2062 dnslist_domain = dnslist_matched = NULL;
2064 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2065 spf_result_guessed = FALSE;
2067 #ifndef DISABLE_DKIM
2068 dkim_cur_signer = dkim_signers =
2069 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2070 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2071 f.dkim_disable_verify = FALSE;
2072 dkim_collect_input = 0;
2073 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2074 dkim_key_length = 0;
2076 #ifdef SUPPORT_DMARC
2077 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2078 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2079 dmarc_used_domain = NULL;
2081 #ifdef EXPERIMENTAL_ARC
2082 arc_state = arc_state_reason = NULL;
2083 arc_received_instance = 0;
2087 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2088 #ifndef DISABLE_PRDR
2089 prdr_requested = FALSE;
2092 message_smtputf8 = FALSE;
2094 body_linecount = body_zerocount = 0;
2096 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2097 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2098 /* Note that ratelimiters_conn persists across resets. */
2100 /* Reset message ACL variables */
2104 /* Warning log messages are saved in malloc store. They are saved to avoid
2105 repetition in the same message, but it seems right to repeat them for different
2108 while (acl_warn_logged)
2110 string_item *this = acl_warn_logged;
2111 acl_warn_logged = acl_warn_logged->next;
2114 store_reset(reset_point);
2115 return store_mark();
2122 /*************************************************
2123 * Initialize for incoming batched SMTP message *
2124 *************************************************/
2126 /* This function is called from smtp_setup_msg() in the case when
2127 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2128 of messages in one file with SMTP commands between them. All errors must be
2129 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2130 relevant. After an error on a sender, or an invalid recipient, the remainder
2131 of the message is skipped. The value of received_protocol is already set.
2134 Returns: > 0 message successfully started (reached DATA)
2135 = 0 QUIT read or end of file reached
2136 < 0 should not occur
2140 smtp_setup_batch_msg(void)
2143 rmark reset_point = store_mark();
2145 /* Save the line count at the start of each transaction - single commands
2146 like HELO and RSET count as whole transactions. */
2148 bsmtp_transaction_linecount = receive_linecount;
2150 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2152 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2153 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2155 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2156 value. The values are 2 larger than the required yield of the function. */
2161 uschar *recipient = NULL;
2162 int start, end, sender_domain, recipient_domain;
2164 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2166 /* The HELO/EHLO commands set sender_address_helo if they have
2167 valid data; otherwise they are ignored, except that they do
2168 a reset of the state. */
2173 check_helo(smtp_cmd_data);
2177 cancel_cutthrough_connection(TRUE, US"RSET received");
2178 reset_point = smtp_reset(reset_point);
2179 bsmtp_transaction_linecount = receive_linecount;
2183 /* The MAIL FROM command requires an address as an operand. All we
2184 do here is to parse it for syntactic correctness. The form "<>" is
2185 a special case which converts into an empty string. The start/end
2186 pointers in the original are not used further for this address, as
2187 it is the canonical extracted address which is all that is kept. */
2190 smtp_mailcmd_count++; /* Count for no-mail log */
2191 if (sender_address != NULL)
2192 /* The function moan_smtp_batch() does not return. */
2193 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2195 if (smtp_cmd_data[0] == 0)
2196 /* The function moan_smtp_batch() does not return. */
2197 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2199 /* Reset to start of message */
2201 cancel_cutthrough_connection(TRUE, US"MAIL received");
2202 reset_point = smtp_reset(reset_point);
2204 /* Apply SMTP rewrite */
2206 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2207 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2208 US"", global_rewrite_rules) : smtp_cmd_data;
2210 /* Extract the address; the TRUE flag allows <> as valid */
2213 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2217 /* The function moan_smtp_batch() does not return. */
2218 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2220 sender_address = string_copy(raw_sender);
2222 /* Qualify unqualified sender addresses if permitted to do so. */
2225 && sender_address[0] != 0 && sender_address[0] != '@')
2226 if (f.allow_unqualified_sender)
2228 sender_address = rewrite_address_qualify(sender_address, FALSE);
2229 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2230 "and rewritten\n", raw_sender);
2232 /* The function moan_smtp_batch() does not return. */
2234 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2239 /* The RCPT TO command requires an address as an operand. All we do
2240 here is to parse it for syntactic correctness. There may be any number
2241 of RCPT TO commands, specifying multiple senders. We build them all into
2242 a data structure that is in argc/argv format. The start/end values
2243 given by parse_extract_address are not used, as we keep only the
2244 extracted address. */
2247 if (!sender_address)
2248 /* The function moan_smtp_batch() does not return. */
2249 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2251 if (smtp_cmd_data[0] == 0)
2252 /* The function moan_smtp_batch() does not return. */
2253 moan_smtp_batch(smtp_cmd_buffer,
2254 "501 RCPT TO must have an address operand");
2256 /* Check maximum number allowed */
2258 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2259 /* The function moan_smtp_batch() does not return. */
2260 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2261 recipients_max_reject? "552": "452");
2263 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2264 recipient address */
2266 recipient = rewrite_existflags & rewrite_smtp
2267 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2268 global_rewrite_rules)
2271 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2272 &recipient_domain, FALSE);
2275 /* The function moan_smtp_batch() does not return. */
2276 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2278 /* If the recipient address is unqualified, qualify it if permitted. Then
2279 add it to the list of recipients. */
2281 if (!recipient_domain)
2282 if (f.allow_unqualified_recipient)
2284 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2286 recipient = rewrite_address_qualify(recipient, TRUE);
2288 /* The function moan_smtp_batch() does not return. */
2290 moan_smtp_batch(smtp_cmd_buffer,
2291 "501 recipient address must contain a domain");
2293 receive_add_recipient(recipient, -1);
2297 /* The DATA command is legal only if it follows successful MAIL FROM
2298 and RCPT TO commands. This function is complete when a valid DATA
2299 command is encountered. */
2302 if (!sender_address || recipients_count <= 0)
2303 /* The function moan_smtp_batch() does not return. */
2304 if (!sender_address)
2305 moan_smtp_batch(smtp_cmd_buffer,
2306 "503 MAIL FROM:<sender> command must precede DATA");
2308 moan_smtp_batch(smtp_cmd_buffer,
2309 "503 RCPT TO:<recipient> must precede DATA");
2312 done = 3; /* DATA successfully achieved */
2313 message_ended = END_NOTENDED; /* Indicate in middle of message */
2318 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2325 bsmtp_transaction_linecount = receive_linecount;
2330 f.smtp_in_quit = TRUE;
2337 /* The function moan_smtp_batch() does not return. */
2338 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2343 /* The function moan_smtp_batch() does not return. */
2344 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2349 /* The function moan_smtp_batch() does not return. */
2350 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2355 return done - 2; /* Convert yield values */
2363 smtp_log_tls_fail(uschar * errstr)
2365 uschar * conn_info = smtp_get_connection_info();
2367 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2368 /* I'd like to get separated H= here, but too hard for now */
2370 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2384 socklen_t len = sizeof(is_fastopen);
2386 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2387 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2389 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2394 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2395 f.tcp_in_fastopen = TRUE;
2398 else DEBUG(D_receive)
2399 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2401 # elif defined(TCP_INFO)
2402 struct tcp_info tinfo;
2403 socklen_t len = sizeof(tinfo);
2405 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2406 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2407 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2410 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2411 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2415 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2418 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2419 f.tcp_in_fastopen = TRUE;
2421 else DEBUG(D_receive)
2422 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2428 /*************************************************
2429 * Start an SMTP session *
2430 *************************************************/
2432 /* This function is called at the start of an SMTP session. Thereafter,
2433 smtp_setup_msg() is called to initiate each separate message. This
2434 function does host-specific testing, and outputs the banner line.
2437 Returns: FALSE if the session can not continue; something has
2438 gone wrong, or the connection to the host is blocked
2442 smtp_start_session(void)
2445 uschar *user_msg, *log_msg;
2450 gettimeofday(&smtp_connection_start, NULL);
2451 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2452 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2455 /* Default values for certain variables */
2457 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2458 smtp_mailcmd_count = 0;
2459 count_nonmail = TRUE_UNSET;
2460 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2461 smtp_delay_mail = smtp_rlm_base;
2462 fl.auth_advertised = FALSE;
2463 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2464 f.pipelining_enable = TRUE;
2465 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2466 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2468 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2469 authentication settings from -oMaa to remain in force. */
2471 if (!host_checking && !f.sender_host_notsocket)
2472 sender_host_auth_pubname = sender_host_authenticated = NULL;
2473 authenticated_by = NULL;
2476 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2477 tls_in.ourcert = tls_in.peercert = NULL;
2479 tls_in.ocsp = OCSP_NOT_REQ;
2480 fl.tls_advertised = FALSE;
2482 fl.dsn_advertised = FALSE;
2484 fl.smtputf8_advertised = FALSE;
2487 /* Reset ACL connection variables */
2491 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2493 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2495 smtp_cmd_buffer[0] = 0;
2496 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2498 /* For batched input, the protocol setting can be overridden from the
2499 command line by a trusted caller. */
2501 if (smtp_batched_input)
2503 if (!received_protocol) received_protocol = US"local-bsmtp";
2506 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2507 reset later if any of EHLO/AUTH/STARTTLS are received. */
2511 (sender_host_address ? protocols : protocols_local) [pnormal];
2513 /* Set up the buffer for inputting using direct read() calls, and arrange to
2514 call the local functions instead of the standard C ones. Place a NUL at the
2515 end of the buffer to safety-stop C-string reads from it. */
2517 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2518 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2519 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2521 receive_getc = smtp_getc;
2522 receive_getbuf = smtp_getbuf;
2523 receive_get_cache = smtp_get_cache;
2524 receive_ungetc = smtp_ungetc;
2525 receive_feof = smtp_feof;
2526 receive_ferror = smtp_ferror;
2527 receive_smtp_buffered = smtp_buffered;
2528 smtp_inptr = smtp_inend = smtp_inbuffer;
2529 smtp_had_eof = smtp_had_error = 0;
2531 /* Set up the message size limit; this may be host-specific */
2533 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2534 if (expand_string_message)
2536 if (thismessage_size_limit == -1)
2537 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2538 "%s", expand_string_message);
2540 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2541 "%s", expand_string_message);
2542 smtp_closedown(US"Temporary local problem - please try later");
2546 /* When a message is input locally via the -bs or -bS options, sender_host_
2547 unknown is set unless -oMa was used to force an IP address, in which case it
2548 is checked like a real remote connection. When -bs is used from inetd, this
2549 flag is not set, causing the sending host to be checked. The code that deals
2550 with IP source routing (if configured) is never required for -bs or -bS and
2551 the flag sender_host_notsocket is used to suppress it.
2553 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2554 reserve for certain hosts and/or networks. */
2556 if (!f.sender_host_unknown)
2559 BOOL reserved_host = FALSE;
2561 /* Look up IP options (source routing info) on the socket if this is not an
2562 -oMa "host", and if any are found, log them and drop the connection.
2564 Linux (and others now, see below) is different to everyone else, so there
2565 has to be some conditional compilation here. Versions of Linux before 2.1.15
2566 used a structure whose name was "options". Somebody finally realized that
2567 this name was silly, and it got changed to "ip_options". I use the
2568 newer name here, but there is a fudge in the script that sets up os.h
2569 to define a macro in older Linux systems.
2571 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2572 glibc 2, which has chosen ip_opts for the structure name. This is now
2573 really a glibc thing rather than a Linux thing, so the condition name
2574 has been changed to reflect this. It is relevant also to GNU/Hurd.
2576 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2577 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2578 a special macro defined in the os.h file.
2580 Some DGUX versions on older hardware appear not to support IP options at
2581 all, so there is now a general macro which can be set to cut out this
2584 How to do this properly in IPv6 is not yet known. */
2586 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2588 #ifdef GLIBC_IP_OPTIONS
2589 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2594 #elif defined DARWIN_IP_OPTIONS
2600 if (!host_checking && !f.sender_host_notsocket)
2603 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2604 struct ip_options *ipopt = store_get(optlen, FALSE);
2606 struct ip_opts ipoptblock;
2607 struct ip_opts *ipopt = &ipoptblock;
2608 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2610 struct ipoption ipoptblock;
2611 struct ipoption *ipopt = &ipoptblock;
2612 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2615 /* Occasional genuine failures of getsockopt() have been seen - for
2616 example, "reset by peer". Therefore, just log and give up on this
2617 call, unless the error is ENOPROTOOPT. This error is given by systems
2618 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2619 of writing. So for that error, carry on - we just can't do an IP options
2622 DEBUG(D_receive) debug_printf("checking for IP options\n");
2624 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2627 if (errno != ENOPROTOOPT)
2629 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2630 host_and_ident(FALSE), strerror(errno));
2631 smtp_printf("451 SMTP service not available\r\n", FALSE);
2636 /* Deal with any IP options that are set. On the systems I have looked at,
2637 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2638 more logging data than will fit in big_buffer. Nevertheless, after somebody
2639 questioned this code, I've added in some paranoid checking. */
2641 else if (optlen > 0)
2643 uschar *p = big_buffer;
2644 uschar *pend = big_buffer + big_buffer_size;
2647 struct in_addr addr;
2650 uschar *optstart = US (ipopt->__data);
2652 uschar *optstart = US (ipopt->ip_opts);
2654 uschar *optstart = US (ipopt->ipopt_list);
2657 DEBUG(D_receive) debug_printf("IP options exist\n");
2659 Ustrcpy(p, "IP options on incoming call:");
2662 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2675 if (!string_format(p, pend-p, " %s [@%s",
2676 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2678 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2680 inet_ntoa(ipopt->ip_dst)))
2682 inet_ntoa(ipopt->ipopt_dst)))
2690 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2692 while (optcount-- > 0)
2694 memcpy(&addr, adptr, sizeof(addr));
2695 if (!string_format(p, pend - p - 1, "%s%s",
2696 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2702 adptr += sizeof(struct in_addr);
2710 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2713 for (int i = 0; i < opt[1]; i++)
2714 p += sprintf(CS p, "%2.2x ", opt[i]);
2722 log_write(0, LOG_MAIN, "%s", big_buffer);
2724 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2726 log_write(0, LOG_MAIN|LOG_REJECT,
2727 "connection from %s refused (IP options)", host_and_ident(FALSE));
2729 smtp_printf("554 SMTP service not available\r\n", FALSE);
2733 /* Length of options = 0 => there are no options */
2735 else DEBUG(D_receive) debug_printf("no IP options found\n");
2737 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2739 /* Set keep-alive in socket options. The option is on by default. This
2740 setting is an attempt to get rid of some hanging connections that stick in
2741 read() when the remote end (usually a dialup) goes away. */
2743 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2744 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2746 /* If the current host matches host_lookup, set the name by doing a
2747 reverse lookup. On failure, sender_host_name will be NULL and
2748 host_lookup_failed will be TRUE. This may or may not be serious - optional
2751 if (verify_check_host(&host_lookup) == OK)
2753 (void)host_name_lookup();
2754 host_build_sender_fullhost();
2757 /* Delay this until we have the full name, if it is looked up. */
2759 set_process_info("handling incoming connection from %s",
2760 host_and_ident(FALSE));
2762 /* Expand smtp_receive_timeout, if needed */
2764 if (smtp_receive_timeout_s)
2767 if ( !(exp = expand_string(smtp_receive_timeout_s))
2769 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2771 log_write(0, LOG_MAIN|LOG_PANIC,
2772 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2775 /* Test for explicit connection rejection */
2777 if (verify_check_host(&host_reject_connection) == OK)
2779 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2780 "from %s (host_reject_connection)", host_and_ident(FALSE));
2781 smtp_printf("554 SMTP service not available\r\n", FALSE);
2785 /* Test with TCP Wrappers if so configured. There is a problem in that
2786 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2787 such as disks dying. In these cases, it is desirable to reject with a 4xx
2788 error instead of a 5xx error. There isn't a "right" way to detect such
2789 problems. The following kludge is used: errno is zeroed before calling
2790 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2791 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2794 #ifdef USE_TCP_WRAPPERS
2796 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2797 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2798 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2799 expand_string_message);
2801 if (!hosts_ctl(tcp_wrappers_name,
2802 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2803 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2804 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2806 if (errno == 0 || errno == ENOENT)
2808 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2809 log_write(L_connection_reject,
2810 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2811 "(tcp wrappers)", host_and_ident(FALSE));
2812 smtp_printf("554 SMTP service not available\r\n", FALSE);
2816 int save_errno = errno;
2817 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2818 "errno value %d\n", save_errno);
2819 log_write(L_connection_reject,
2820 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2821 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2822 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2828 /* Check for reserved slots. The value of smtp_accept_count has already been
2829 incremented to include this process. */
2831 if (smtp_accept_max > 0 &&
2832 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2834 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2836 log_write(L_connection_reject,
2837 LOG_MAIN, "temporarily refused connection from %s: not in "
2838 "reserve list: connected=%d max=%d reserve=%d%s",
2839 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2840 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2841 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2842 "please try again later\r\n", FALSE, smtp_active_hostname);
2845 reserved_host = TRUE;
2848 /* If a load level above which only messages from reserved hosts are
2849 accepted is set, check the load. For incoming calls via the daemon, the
2850 check is done in the superior process if there are no reserved hosts, to
2851 save a fork. In all cases, the load average will already be available
2852 in a global variable at this point. */
2854 if (smtp_load_reserve >= 0 &&
2855 load_average > smtp_load_reserve &&
2857 verify_check_host(&smtp_reserve_hosts) != OK)
2859 log_write(L_connection_reject,
2860 LOG_MAIN, "temporarily refused connection from %s: not in "
2861 "reserve list and load average = %.2f", host_and_ident(FALSE),
2862 (double)load_average/1000.0);
2863 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2864 smtp_active_hostname);
2868 /* Determine whether unqualified senders or recipients are permitted
2869 for this host. Unfortunately, we have to do this every time, in order to
2870 set the flags so that they can be inspected when considering qualifying
2871 addresses in the headers. For a site that permits no qualification, this
2872 won't take long, however. */
2874 f.allow_unqualified_sender =
2875 verify_check_host(&sender_unqualified_hosts) == OK;
2877 f.allow_unqualified_recipient =
2878 verify_check_host(&recipient_unqualified_hosts) == OK;
2880 /* Determine whether HELO/EHLO is required for this host. The requirement
2881 can be hard or soft. */
2883 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2884 if (!fl.helo_required)
2885 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2887 /* Determine whether this hosts is permitted to send syntactic junk
2888 after a HELO or EHLO command. */
2890 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2893 /* For batch SMTP input we are now done. */
2895 if (smtp_batched_input) return TRUE;
2897 /* If valid Proxy Protocol source is connecting, set up session.
2898 * Failure will not allow any SMTP function other than QUIT. */
2900 #ifdef SUPPORT_PROXY
2901 proxy_session = FALSE;
2902 f.proxy_session_failed = FALSE;
2903 if (check_proxy_protocol_host())
2904 setup_proxy_protocol_host();
2907 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2908 smtps port for use with older style SSL MTAs. */
2911 if (tls_in.on_connect)
2913 if (tls_server_start(&user_msg) != OK)
2914 return smtp_log_tls_fail(user_msg);
2915 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2919 /* Run the connect ACL if it exists */
2922 if (acl_smtp_connect)
2925 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2928 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2933 /* Output the initial message for a two-way SMTP connection. It may contain
2934 newlines, which then cause a multi-line response to be given. */
2936 code = US"220"; /* Default status code */
2937 esc = US""; /* Default extended status code */
2938 esclen = 0; /* Length of esc */
2942 if (!(s = expand_string(smtp_banner)))
2943 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2944 "failed: %s", smtp_banner, expand_string_message);
2950 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2954 esclen = codelen - 4;
2958 /* Remove any terminating newlines; might as well remove trailing space too */
2961 while (p > s && isspace(p[-1])) p--;
2964 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2965 is all contained in a single IP packet. The original code wrote out the
2966 greeting using several calls to fprint/fputc, and on busy servers this could
2967 cause it to be split over more than one packet - which caused CC:Mail to fall
2968 over when it got the second part of the greeting after sending its first
2969 command. Sigh. To try to avoid this, build the complete greeting message
2970 first, and output it in one fell swoop. This gives a better chance of it
2971 ending up as a single packet. */
2973 ss = string_get(256);
2976 do /* At least once, in case we have an empty string */
2979 uschar *linebreak = Ustrchr(p, '\n');
2980 ss = string_catn(ss, code, 3);
2984 ss = string_catn(ss, US" ", 1);
2988 len = linebreak - p;
2989 ss = string_catn(ss, US"-", 1);
2991 ss = string_catn(ss, esc, esclen);
2992 ss = string_catn(ss, p, len);
2993 ss = string_catn(ss, US"\r\n", 2);
2999 /* Before we write the banner, check that there is no input pending, unless
3000 this synchronisation check is disabled. */
3002 #ifndef DISABLE_PIPE_CONNECT
3003 fl.pipe_connect_acceptable =
3004 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3007 if (fl.pipe_connect_acceptable)
3008 f.smtp_in_early_pipe_used = TRUE;
3014 unsigned n = smtp_inend - smtp_inptr;
3015 if (n > 128) n = 128;
3017 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3018 "synchronization error (input sent without waiting for greeting): "
3019 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3020 string_printing(string_copyn(smtp_inptr, n)));
3021 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3025 /* Now output the banner */
3026 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3029 #ifndef DISABLE_PIPE_CONNECT
3030 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3034 string_from_gstring(ss));
3036 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3037 handshake arrived. If so we must have managed a TFO. */
3040 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3050 /*************************************************
3051 * Handle SMTP syntax and protocol errors *
3052 *************************************************/
3054 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3055 to do so. Then transmit the error response. The return value depends on the
3056 number of syntax and protocol errors in this SMTP session.
3059 type error type, given as a log flag bit
3060 code response code; <= 0 means don't send a response
3061 data data to reflect in the response (can be NULL)
3062 errmess the error message
3064 Returns: -1 limit of syntax/protocol errors NOT exceeded
3065 +1 limit of syntax/protocol errors IS exceeded
3067 These values fit in with the values of the "done" variable in the main
3068 processing loop in smtp_setup_msg(). */
3071 synprot_error(int type, int code, uschar *data, uschar *errmess)
3075 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3076 type == L_smtp_syntax_error ? "syntax" : "protocol",
3077 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3079 if (++synprot_error_count > smtp_max_synprot_errors)
3082 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3083 "syntax or protocol errors (last command was \"%s\", %s)",
3084 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3085 string_from_gstring(s_connhad_log(NULL))
3091 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3092 data ? data : US"", data ? US": " : US"", errmess);
3094 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3103 /*************************************************
3104 * Send SMTP response, possibly multiline *
3105 *************************************************/
3107 /* There are, it seems, broken clients out there that cannot handle multiline
3108 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3109 output nothing for non-final calls, and only the first line for anything else.
3112 code SMTP code, may involve extended status codes
3113 codelen length of smtp code; if > 4 there's an ESC
3114 final FALSE if the last line isn't the final line
3115 msg message text, possibly containing newlines
3121 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3126 if (!final && f.no_multiline_responses) return;
3131 esclen = codelen - 4;
3134 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3135 have had the same. Note: this code is also present in smtp_printf(). It would
3136 be tidier to have it only in one place, but when it was added, it was easier to
3137 do it that way, so as not to have to mess with the code for the RCPT command,
3138 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3140 if (fl.rcpt_in_progress)
3142 if (rcpt_smtp_response == NULL)
3143 rcpt_smtp_response = string_copy(msg);
3144 else if (fl.rcpt_smtp_response_same &&
3145 Ustrcmp(rcpt_smtp_response, msg) != 0)
3146 fl.rcpt_smtp_response_same = FALSE;
3147 fl.rcpt_in_progress = FALSE;
3150 /* Now output the message, splitting it up into multiple lines if necessary.
3151 We only handle pipelining these responses as far as nonfinal/final groups,
3152 not the whole MAIL/RCPT/DATA response set. */
3156 uschar *nl = Ustrchr(msg, '\n');
3159 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3162 else if (nl[1] == 0 || f.no_multiline_responses)
3164 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3165 (int)(nl - msg), msg);
3170 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3172 Uskip_whitespace(&msg);
3180 /*************************************************
3181 * Parse user SMTP message *
3182 *************************************************/
3184 /* This function allows for user messages overriding the response code details
3185 by providing a suitable response code string at the start of the message
3186 user_msg. Check the message for starting with a response code and optionally an
3187 extended status code. If found, check that the first digit is valid, and if so,
3188 change the code pointer and length to use the replacement. An invalid code
3189 causes a panic log; in this case, if the log messages is the same as the user
3190 message, we must also adjust the value of the log message to show the code that
3191 is actually going to be used (the original one).
3193 This function is global because it is called from receive.c as well as within
3196 Note that the code length returned includes the terminating whitespace
3197 character, which is always included in the regex match.
3200 code SMTP code, may involve extended status codes
3201 codelen length of smtp code; if > 4 there's an ESC
3203 log_msg optional log message, to be adjusted with the new SMTP code
3204 check_valid if true, verify the response code
3210 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3216 if (!msg || !*msg) return;
3218 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3219 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3221 if (check_valid && (*msg)[0] != (*code)[0])
3223 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3224 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3225 if (log_msg != NULL && *log_msg == *msg)
3226 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3231 *codelen = ovector[1]; /* Includes final space */
3233 *msg += ovector[1]; /* Chop the code off the message */
3240 /*************************************************
3241 * Handle an ACL failure *
3242 *************************************************/
3244 /* This function is called when acl_check() fails. As well as calls from within
3245 this module, it is called from receive.c for an ACL after DATA. It sorts out
3246 logging the incident, and sends the error response. A message containing
3247 newlines is turned into a multiline SMTP response, but for logging, only the
3250 There's a table of default permanent failure response codes to use in
3251 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3252 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3253 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3254 state, because there are broken clients that try VRFY before RCPT. A 5xx
3255 response should be given only when the address is positively known to be
3256 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3257 no explicit code, but if there is one we let it know best.
3258 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3260 From Exim 4.63, it is possible to override the response code details by
3261 providing a suitable response code string at the start of the message provided
3262 in user_msg. The code's first digit is checked for validity.
3265 where where the ACL was called from
3267 user_msg a message that can be included in an SMTP response
3268 log_msg a message for logging
3270 Returns: 0 in most cases
3271 2 if the failure code was FAIL_DROP, in which case the
3272 SMTP connection should be dropped (this value fits with the
3273 "done" variable in smtp_setup_msg() below)
3277 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3279 BOOL drop = rc == FAIL_DROP;
3283 uschar *sender_info = US"";
3285 #ifdef WITH_CONTENT_SCAN
3286 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3288 where == ACL_WHERE_PREDATA ? US"DATA" :
3289 where == ACL_WHERE_DATA ? US"after DATA" :
3290 #ifndef DISABLE_PRDR
3291 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3294 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3295 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3297 if (drop) rc = FAIL;
3299 /* Set the default SMTP code, and allow a user message to change it. */
3301 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3302 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3303 where != ACL_WHERE_VRFY);
3305 /* We used to have sender_address here; however, there was a bug that was not
3306 updating sender_address after a rewrite during a verify. When this bug was
3307 fixed, sender_address at this point became the rewritten address. I'm not sure
3308 this is what should be logged, so I've changed to logging the unrewritten
3309 address to retain backward compatibility. */
3311 #ifndef WITH_CONTENT_SCAN
3312 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3314 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3317 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3318 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3319 sender_host_authenticated ? US" A=" : US"",
3320 sender_host_authenticated ? sender_host_authenticated : US"",
3321 sender_host_authenticated && authenticated_id ? US":" : US"",
3322 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3326 /* If there's been a sender verification failure with a specific message, and
3327 we have not sent a response about it yet, do so now, as a preliminary line for
3328 failures, but not defers. However, always log it for defer, and log it for fail
3329 unless the sender_verify_fail log selector has been turned off. */
3331 if (sender_verified_failed &&
3332 !testflag(sender_verified_failed, af_sverify_told))
3334 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3335 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3337 setflag(sender_verified_failed, af_sverify_told);
3339 if (rc != FAIL || LOGGING(sender_verify_fail))
3340 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3341 host_and_ident(TRUE),
3342 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3343 sender_verified_failed->address,
3344 (sender_verified_failed->message == NULL)? US"" :
3345 string_sprintf(": %s", sender_verified_failed->message));
3347 if (rc == FAIL && sender_verified_failed->user_message)
3348 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3349 testflag(sender_verified_failed, af_verify_pmfail)?
3350 "Postmaster verification failed while checking <%s>\n%s\n"
3351 "Several RFCs state that you are required to have a postmaster\n"
3352 "mailbox for each mail domain. This host does not accept mail\n"
3353 "from domains whose servers reject the postmaster address."
3355 testflag(sender_verified_failed, af_verify_nsfail)?
3356 "Callback setup failed while verifying <%s>\n%s\n"
3357 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3358 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3359 "RFC requirements, and stops you from receiving standard bounce\n"
3360 "messages. This host does not accept mail from domains whose servers\n"
3363 "Verification failed for <%s>\n%s",
3364 sender_verified_failed->address,
3365 sender_verified_failed->user_message));
3367 fl.rcpt_in_progress = save_rcpt_in_progress;
3370 /* Sort out text for logging */
3372 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3373 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3375 /* Send permanent failure response to the command, but the code used isn't
3376 always a 5xx one - see comments at the start of this function. If the original
3377 rc was FAIL_DROP we drop the connection and yield 2. */
3380 smtp_respond(smtp_code, codelen, TRUE,
3381 user_msg ? user_msg : US"Administrative prohibition");
3383 /* Send temporary failure response to the command. Don't give any details,
3384 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3385 verb, and for a header verify when smtp_return_error_details is set.
3387 This conditional logic is all somewhat of a mess because of the odd
3388 interactions between temp_details and return_error_details. One day it should
3389 be re-implemented in a tidier fashion. */
3392 if (f.acl_temp_details && user_msg)
3394 if ( smtp_return_error_details
3395 && sender_verified_failed
3396 && sender_verified_failed->message
3398 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3400 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3403 smtp_respond(smtp_code, codelen, TRUE,
3404 US"Temporary local problem - please try later");
3406 /* Log the incident to the logs that are specified by log_reject_target
3407 (default main, reject). This can be empty to suppress logging of rejections. If
3408 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3409 is closing if required and return 2. */
3411 if (log_reject_target != 0)
3414 gstring * g = s_tlslog(NULL);
3415 uschar * tls = string_from_gstring(g);
3416 if (!tls) tls = US"";
3418 uschar * tls = US"";
3420 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3421 log_reject_target, "%s%s%s %s%srejected %s%s",
3422 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3423 host_and_ident(TRUE),
3426 rc == FAIL ? US"" : US"temporarily ",
3430 if (!drop) return 0;
3432 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3433 smtp_get_connection_info());
3435 /* Run the not-quit ACL, but without any custom messages. This should not be a
3436 problem, because we get here only if some other ACL has issued "drop", and
3437 in that case, *its* custom messages will have been used above. */
3439 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3446 /*************************************************
3447 * Handle SMTP exit when QUIT is not given *
3448 *************************************************/
3450 /* This function provides a logging/statistics hook for when an SMTP connection
3451 is dropped on the floor or the other end goes away. It's a global function
3452 because it's called from receive.c as well as this module. As well as running
3453 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3454 response, either with a custom message from the ACL, or using a default. There
3455 is one case, however, when no message is output - after "drop". In that case,
3456 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3457 passed to this function.
3459 In case things go wrong while processing this function, causing an error that
3460 may re-enter this function, there is a recursion check.
3463 reason What $smtp_notquit_reason will be set to in the ACL;
3464 if NULL, the ACL is not run
3465 code The error code to return as part of the response
3466 defaultrespond The default message if there's no user_msg
3472 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3475 uschar *user_msg = NULL;
3476 uschar *log_msg = NULL;
3478 /* Check for recursive call */
3480 if (fl.smtp_exit_function_called)
3482 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3486 fl.smtp_exit_function_called = TRUE;
3488 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3490 if (acl_smtp_notquit && reason)
3492 smtp_notquit_reason = reason;
3493 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3494 &log_msg)) == ERROR)
3495 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3499 /* If the connection was dropped, we certainly are no longer talking TLS */
3500 tls_in.active.sock = -1;
3502 /* Write an SMTP response if we are expected to give one. As the default
3503 responses are all internal, they should be reasonable size. */
3505 if (code && defaultrespond)
3508 smtp_respond(code, 3, TRUE, user_msg);
3514 va_start(ap, defaultrespond);
3515 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3517 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3526 /*************************************************
3527 * Verify HELO argument *
3528 *************************************************/
3530 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3531 matched. It is also called from ACL processing if verify = helo is used and
3532 verification was not previously tried (i.e. helo_try_verify_hosts was not
3533 matched). The result of its processing is to set helo_verified and
3534 helo_verify_failed. These variables should both be FALSE for this function to
3537 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3538 for IPv6 ::ffff: literals.
3541 Returns: TRUE if testing was completed;
3542 FALSE on a temporary failure
3546 smtp_verify_helo(void)
3550 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3553 if (sender_helo_name == NULL)
3555 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3558 /* Deal with the case of -bs without an IP address */
3560 else if (sender_host_address == NULL)
3562 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3563 f.helo_verified = TRUE;
3566 /* Deal with the more common case when there is a sending IP address */
3568 else if (sender_helo_name[0] == '[')
3570 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3571 Ustrlen(sender_host_address)) == 0;
3574 if (!f.helo_verified)
3576 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3577 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3578 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3583 { if (f.helo_verified) debug_printf("matched host address\n"); }
3586 /* Do a reverse lookup if one hasn't already given a positive or negative
3587 response. If that fails, or the name doesn't match, try checking with a forward
3592 if (sender_host_name == NULL && !host_lookup_failed)
3593 yield = host_name_lookup() != DEFER;
3595 /* If a host name is known, check it and all its aliases. */
3597 if (sender_host_name)
3598 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3600 sender_helo_dnssec = sender_host_dnssec;
3601 HDEBUG(D_receive) debug_printf("matched host name\n");
3605 uschar **aliases = sender_host_aliases;
3607 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3609 sender_helo_dnssec = sender_host_dnssec;
3613 HDEBUG(D_receive) if (f.helo_verified)
3614 debug_printf("matched alias %s\n", *(--aliases));
3617 /* Final attempt: try a forward lookup of the helo name */
3619 if (!f.helo_verified)
3623 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3625 {.request = US"*", .require = US""};
3627 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3629 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3630 NULL, NULL, NULL, &d, NULL, NULL);
3631 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3632 for (host_item * hh = &h; hh; hh = hh->next)
3633 if (Ustrcmp(hh->address, sender_host_address) == 0)
3635 f.helo_verified = TRUE;
3636 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3638 debug_printf("IP address for %s matches calling address\n"
3639 "Forward DNS security status: %sverified\n",
3640 sender_helo_name, sender_helo_dnssec ? "" : "un");
3646 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3653 /*************************************************
3654 * Send user response message *
3655 *************************************************/
3657 /* This function is passed a default response code and a user message. It calls
3658 smtp_message_code() to check and possibly modify the response code, and then
3659 calls smtp_respond() to transmit the response. I put this into a function
3660 just to avoid a lot of repetition.
3663 code the response code
3664 user_msg the user message
3670 smtp_user_msg(uschar *code, uschar *user_msg)
3673 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3674 smtp_respond(code, len, TRUE, user_msg);
3680 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3682 const uschar *set_id = NULL;
3685 /* Run the checking code, passing the remainder of the command line as
3686 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3687 it as the only set numerical variable. The authenticator may set $auth<n>
3688 and also set other numeric variables. The $auth<n> variables are preferred
3689 nowadays; the numerical variables remain for backwards compatibility.
3691 Afterwards, have a go at expanding the set_id string, even if
3692 authentication failed - for bad passwords it can be useful to log the
3693 userid. On success, require set_id to expand and exist, and put it in
3694 authenticated_id. Save this in permanent store, as the working store gets
3695 reset at HELO, RSET, etc. */
3697 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3699 expand_nlength[0] = 0; /* $0 contains nothing */
3701 rc = (au->info->servercode)(au, smtp_cmd_data);
3702 if (au->set_id) set_id = expand_string(au->set_id);
3703 expand_nmax = -1; /* Reset numeric variables */
3704 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3706 /* The value of authenticated_id is stored in the spool file and printed in
3707 log lines. It must not contain binary zeros or newline characters. In
3708 normal use, it never will, but when playing around or testing, this error
3709 can (did) happen. To guard against this, ensure that the id contains only
3710 printing characters. */
3712 if (set_id) set_id = string_printing(set_id);
3714 /* For the non-OK cases, set up additional logging data if set_id
3718 set_id = set_id && *set_id
3719 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3721 /* Switch on the result */
3726 if (!au->set_id || set_id) /* Complete success */
3728 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3729 sender_host_authenticated = au->name;
3730 sender_host_auth_pubname = au->public_name;
3731 authentication_failed = FALSE;
3732 authenticated_fail_id = NULL; /* Impossible to already be set? */
3735 (sender_host_address ? protocols : protocols_local)
3736 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3737 *s = *ss = US"235 Authentication succeeded";
3738 authenticated_by = au;
3742 /* Authentication succeeded, but we failed to expand the set_id string.
3743 Treat this as a temporary error. */
3745 auth_defer_msg = expand_string_message;
3749 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3750 *s = string_sprintf("435 Unable to authenticate at present%s",
3751 auth_defer_user_msg);
3752 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3753 set_id, auth_defer_msg);
3757 *s = *ss = US"501 Invalid base64 data";
3761 *s = *ss = US"501 Authentication cancelled";
3765 *s = *ss = US"553 Initial data not expected";
3769 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3770 *s = US"535 Incorrect authentication data";
3771 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3775 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3776 *s = US"435 Internal error";
3777 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3778 "check", set_id, rc);
3790 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3793 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3795 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3797 rd = Ustrlen(recipient) + 1;
3798 *recipient = rewrite_address_qualify(*recipient, TRUE);
3801 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3803 log_write(L_smtp_syntax_error,
3804 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3805 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3813 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3816 f.smtp_in_quit = TRUE;
3817 incomplete_transaction_log(US"QUIT");
3819 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3821 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3825 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3829 smtp_respond(US"221", 3, TRUE, *user_msgp);
3831 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3834 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3837 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3838 smtp_get_connection_info());
3843 smtp_rset_handler(void)
3846 incomplete_transaction_log(US"RSET");
3847 smtp_printf("250 Reset OK\r\n", FALSE);
3848 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3853 /*************************************************
3854 * Initialize for SMTP incoming message *
3855 *************************************************/
3857 /* This function conducts the initial dialogue at the start of an incoming SMTP
3858 message, and builds a list of recipients. However, if the incoming message
3859 is part of a batch (-bS option) a separate function is called since it would
3860 be messy having tests splattered about all over this function. This function
3861 therefore handles the case where interaction is occurring. The input and output
3862 files are set up in smtp_in and smtp_out.
3864 The global recipients_list is set to point to a vector of recipient_item
3865 blocks, whose number is given by recipients_count. This is extended by the
3866 receive_add_recipient() function. The global variable sender_address is set to
3867 the sender's address. The yield is +1 if a message has been successfully
3868 started, 0 if a QUIT command was encountered or the connection was refused from
3869 the particular host, or -1 if the connection was lost.
3873 Returns: > 0 message successfully started (reached DATA)
3874 = 0 QUIT read or end of file reached or call refused
3879 smtp_setup_msg(void)
3882 BOOL toomany = FALSE;
3883 BOOL discarded = FALSE;
3884 BOOL last_was_rej_mail = FALSE;
3885 BOOL last_was_rcpt = FALSE;
3886 rmark reset_point = store_mark();
3888 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3890 /* Reset for start of new message. We allow one RSET not to be counted as a
3891 nonmail command, for those MTAs that insist on sending it between every
3892 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3893 TLS between messages (an Exim client may do this if it has messages queued up
3894 for the host). Note: we do NOT reset AUTH at this point. */
3896 reset_point = smtp_reset(reset_point);
3897 message_ended = END_NOTSTARTED;
3899 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3901 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3902 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3903 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3905 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3908 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3910 had_command_sigterm = 0;
3911 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3913 /* Batched SMTP is handled in a different function. */
3915 if (smtp_batched_input) return smtp_setup_batch_msg();
3917 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3918 value. The values are 2 larger than the required yield of the function. */
3922 const uschar **argv;
3923 uschar *etrn_command;
3924 uschar *etrn_serialize_key;
3926 uschar *log_msg, *smtp_code;
3927 uschar *user_msg = NULL;
3928 uschar *recipient = NULL;
3929 uschar *hello = NULL;
3931 BOOL was_rej_mail = FALSE;
3932 BOOL was_rcpt = FALSE;
3933 void (*oldsignal)(int);
3935 int start, end, sender_domain, recipient_domain;
3938 uschar *orcpt = NULL;
3943 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3944 if ( tls_in.active.sock >= 0
3946 && tls_in.certificate_verified
3947 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3950 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3952 for (auth_instance * au = auths; au; au = au->next)
3953 if (strcmpic(US"tls", au->driver_name) == 0)
3956 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3957 &user_msg, &log_msg)) != OK
3959 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3962 smtp_cmd_data = NULL;
3964 if (smtp_in_auth(au, &s, &ss) == OK)
3965 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3967 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3975 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3976 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3977 US &off, sizeof(off));
3980 switch(smtp_read_command(
3981 #ifndef DISABLE_PIPE_CONNECT
3982 !fl.pipe_connect_acceptable,
3986 GETC_BUFFER_UNLIMITED))
3988 /* The AUTH command is not permitted to occur inside a transaction, and may
3989 occur successfully only once per connection. Actually, that isn't quite
3990 true. When TLS is started, all previous information about a connection must
3991 be discarded, so a new AUTH is permitted at that time.
3993 AUTH may only be used when it has been advertised. However, it seems that
3994 there are clients that send AUTH when it hasn't been advertised, some of
3995 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3996 So there's a get-out that allows this to happen.
3998 AUTH is initially labelled as a "nonmail command" so that one occurrence
3999 doesn't get counted. We change the label here so that multiple failing
4000 AUTHS will eventually hit the nonmail threshold. */
4004 authentication_failed = TRUE;
4005 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4007 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4009 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4010 US"AUTH command used when not advertised");
4013 if (sender_host_authenticated)
4015 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4016 US"already authenticated");
4021 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4022 US"not permitted in mail transaction");
4029 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4030 &user_msg, &log_msg)) != OK
4033 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4037 /* Find the name of the requested authentication mechanism. */
4040 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4042 if (!isalnum(c) && c != '-' && c != '_')
4044 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4045 US"invalid character in authentication mechanism name");
4051 /* If not at the end of the line, we must be at white space. Terminate the
4052 name and move the pointer on to any data that may be present. */
4054 if (*smtp_cmd_data != 0)
4056 *smtp_cmd_data++ = 0;
4057 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4060 /* Search for an authentication mechanism which is configured for use
4061 as a server and which has been advertised (unless, sigh, allow_auth_
4062 unadvertised is set). */
4066 for (au = auths; au; au = au->next)
4067 if (strcmpic(s, au->public_name) == 0 && au->server &&
4068 (au->advertised || f.allow_auth_unadvertised))
4073 c = smtp_in_auth(au, &s, &ss);
4075 smtp_printf("%s\r\n", FALSE, s);
4077 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4078 au->name, host_and_ident(FALSE), ss);
4081 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4082 string_sprintf("%s authentication mechanism not supported", s));
4085 break; /* AUTH_CMD */
4087 /* The HELO/EHLO commands are permitted to appear in the middle of a
4088 session as well as at the beginning. They have the effect of a reset in
4089 addition to their other functions. Their absence at the start cannot be
4090 taken to be an error.
4094 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4095 or 502 failure replies MUST be returned as appropriate. The SMTP
4096 server MUST stay in the same state after transmitting these replies
4097 that it was in before the EHLO was received.
4099 Therefore, we do not do the reset until after checking the command for
4100 acceptability. This change was made for Exim release 4.11. Previously
4101 it did the reset first. */
4114 HELO_EHLO: /* Common code for HELO and EHLO */
4115 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4116 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4118 /* Reject the HELO if its argument was invalid or non-existent. A
4119 successful check causes the argument to be saved in malloc store. */
4121 if (!check_helo(smtp_cmd_data))
4123 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4125 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4126 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4127 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4128 string_printing(smtp_cmd_argument));
4130 if (++synprot_error_count > smtp_max_synprot_errors)
4132 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4133 "syntax or protocol errors (last command was \"%s\", %s)",
4134 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4135 string_from_gstring(s_connhad_log(NULL))
4143 /* If sender_host_unknown is true, we have got here via the -bs interface,
4144 not called from inetd. Otherwise, we are running an IP connection and the
4145 host address will be set. If the helo name is the primary name of this
4146 host and we haven't done a reverse lookup, force one now. If helo_required
4147 is set, ensure that the HELO name matches the actual host. If helo_verify
4148 is set, do the same check, but softly. */
4150 if (!f.sender_host_unknown)
4152 BOOL old_helo_verified = f.helo_verified;
4153 uschar *p = smtp_cmd_data;
4155 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4158 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4159 because otherwise the log can be confusing. */
4161 if ( !sender_host_name
4162 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4163 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4164 (void)host_name_lookup();
4166 /* Rebuild the fullhost info to include the HELO name (and the real name
4167 if it was looked up.) */
4169 host_build_sender_fullhost(); /* Rebuild */
4170 set_process_info("handling%s incoming connection from %s",
4171 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4173 /* Verify if configured. This doesn't give much security, but it does
4174 make some people happy to be able to do it. If helo_required is set,
4175 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4176 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4177 now obsolescent, since the verification can now be requested selectively
4180 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4181 if (fl.helo_required || fl.helo_verify)
4183 BOOL tempfail = !smtp_verify_helo();
4184 if (!f.helo_verified)
4186 if (fl.helo_required)
4188 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4189 tempfail? 451 : 550, hello);
4190 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4191 tempfail? "temporarily " : "",
4192 hello, sender_helo_name, host_and_ident(FALSE));
4193 f.helo_verified = old_helo_verified;
4194 break; /* End of HELO/EHLO processing */
4196 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4197 "helo_try_verify_hosts\n", hello);
4203 /* set up SPF context */
4204 spf_conn_init(sender_helo_name, sender_host_address);
4207 /* Apply an ACL check if one is defined; afterwards, recheck
4208 synchronization in case the client started sending in a delay. */
4211 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4212 &user_msg, &log_msg)) != OK)
4214 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4215 sender_helo_name = NULL;
4216 host_build_sender_fullhost(); /* Rebuild */
4219 #ifndef DISABLE_PIPE_CONNECT
4220 else if (!fl.pipe_connect_acceptable && !check_sync())
4222 else if (!check_sync())
4226 /* Generate an OK reply. The default string includes the ident if present,
4227 and also the IP address if present. Reflecting back the ident is intended
4228 as a deterrent to mail forgers. For maximum efficiency, and also because
4229 some broken systems expect each response to be in a single packet, arrange
4230 that the entire reply is sent in one write(). */
4232 fl.auth_advertised = FALSE;
4233 f.smtp_in_pipelining_advertised = FALSE;
4235 fl.tls_advertised = FALSE;
4237 fl.dsn_advertised = FALSE;
4239 fl.smtputf8_advertised = FALSE;
4242 smtp_code = US"250 "; /* Default response code plus space*/
4245 /* sender_host_name below will be tainted, so save on copy when we hit it */
4246 g = string_get_tainted(24, TRUE);
4247 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4249 smtp_active_hostname,
4250 sender_ident ? sender_ident : US"",
4251 sender_ident ? US" at " : US"",
4252 sender_host_name ? sender_host_name : sender_helo_name);
4254 if (sender_host_address)
4255 g = string_fmt_append(g, " [%s]", sender_host_address);
4258 /* A user-supplied EHLO greeting may not contain more than one line. Note
4259 that the code returned by smtp_message_code() includes the terminating
4260 whitespace character. */
4266 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4267 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4268 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4270 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4271 "newlines: message truncated: %s", string_printing(s));
4274 g = string_cat(NULL, s);
4277 g = string_catn(g, US"\r\n", 2);
4279 /* If we received EHLO, we must create a multiline response which includes
4280 the functions supported. */
4286 /* I'm not entirely happy with this, as an MTA is supposed to check
4287 that it has enough room to accept a message of maximum size before
4288 it sends this. However, there seems little point in not sending it.
4289 The actual size check happens later at MAIL FROM time. By postponing it
4290 till then, VRFY and EXPN can be used after EHLO when space is short. */
4292 if (thismessage_size_limit > 0)
4293 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4294 thismessage_size_limit);
4297 g = string_catn(g, smtp_code, 3);
4298 g = string_catn(g, US"-SIZE\r\n", 7);
4301 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4302 clean; if it has an 8-bit character in its hand, it just sends it. It
4303 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4304 However, some users want this option simply in order to stop MUAs
4305 mangling messages that contain top-bit-set characters. It is therefore
4306 provided as an option. */
4308 if (accept_8bitmime)
4310 g = string_catn(g, smtp_code, 3);
4311 g = string_catn(g, US"-8BITMIME\r\n", 11);
4314 /* Advertise DSN support if configured to do so. */
4315 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4317 g = string_catn(g, smtp_code, 3);
4318 g = string_catn(g, US"-DSN\r\n", 6);
4319 fl.dsn_advertised = TRUE;
4322 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4323 permitted to issue them; a check is made when any host actually tries. */
4327 g = string_catn(g, smtp_code, 3);
4328 g = string_catn(g, US"-ETRN\r\n", 7);
4332 g = string_catn(g, smtp_code, 3);
4333 g = string_catn(g, US"-VRFY\r\n", 7);
4337 g = string_catn(g, smtp_code, 3);
4338 g = string_catn(g, US"-EXPN\r\n", 7);
4341 /* Exim is quite happy with pipelining, so let the other end know that
4342 it is safe to use it, unless advertising is disabled. */
4344 if ( f.pipelining_enable
4345 && verify_check_host(&pipelining_advertise_hosts) == OK)
4347 g = string_catn(g, smtp_code, 3);
4348 g = string_catn(g, US"-PIPELINING\r\n", 13);
4349 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4350 f.smtp_in_pipelining_advertised = TRUE;
4352 #ifndef DISABLE_PIPE_CONNECT
4353 if (fl.pipe_connect_acceptable)
4355 f.smtp_in_early_pipe_advertised = TRUE;
4356 g = string_catn(g, smtp_code, 3);
4357 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4363 /* If any server authentication mechanisms are configured, advertise
4364 them if the current host is in auth_advertise_hosts. The problem with
4365 advertising always is that some clients then require users to
4366 authenticate (and aren't configurable otherwise) even though it may not
4367 be necessary (e.g. if the host is in host_accept_relay).
4369 RFC 2222 states that SASL mechanism names contain only upper case
4370 letters, so output the names in upper case, though we actually recognize
4371 them in either case in the AUTH command. */
4375 && !sender_host_authenticated
4377 && verify_check_host(&auth_advertise_hosts) == OK
4381 for (auth_instance * au = auths; au; au = au->next)
4383 au->advertised = FALSE;
4386 DEBUG(D_auth+D_expand) debug_printf_indent(
4387 "Evaluating advertise_condition for %s %s athenticator\n",
4388 au->name, au->public_name);
4389 if ( !au->advertise_condition
4390 || expand_check_condition(au->advertise_condition, au->name,
4397 g = string_catn(g, smtp_code, 3);
4398 g = string_catn(g, US"-AUTH", 5);
4400 fl.auth_advertised = TRUE;
4403 g = string_catn(g, US" ", 1);
4404 g = string_cat (g, au->public_name);
4405 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4406 au->advertised = TRUE;
4411 if (!first) g = string_catn(g, US"\r\n", 2);
4414 /* RFC 3030 CHUNKING */
4416 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4418 g = string_catn(g, smtp_code, 3);
4419 g = string_catn(g, US"-CHUNKING\r\n", 11);
4420 f.chunking_offered = TRUE;
4421 chunking_state = CHUNKING_OFFERED;
4424 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4425 if it has been included in the binary, and the host matches
4426 tls_advertise_hosts. We must *not* advertise if we are already in a
4427 secure connection. */
4430 if (tls_in.active.sock < 0 &&
4431 verify_check_host(&tls_advertise_hosts) != FAIL)
4433 g = string_catn(g, smtp_code, 3);
4434 g = string_catn(g, US"-STARTTLS\r\n", 11);
4435 fl.tls_advertised = TRUE;
4439 #ifndef DISABLE_PRDR
4440 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4443 g = string_catn(g, smtp_code, 3);
4444 g = string_catn(g, US"-PRDR\r\n", 7);
4449 if ( accept_8bitmime
4450 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4452 g = string_catn(g, smtp_code, 3);
4453 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4454 fl.smtputf8_advertised = TRUE;
4458 /* Finish off the multiline reply with one that is always available. */
4460 g = string_catn(g, smtp_code, 3);
4461 g = string_catn(g, US" HELP\r\n", 7);
4464 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4468 if (tls_in.active.sock >= 0)
4469 (void)tls_write(NULL, g->s, g->ptr,
4470 # ifndef DISABLE_PIPE_CONNECT
4471 fl.pipe_connect_acceptable && pipeline_connect_sends());
4477 (void) fwrite(g->s, 1, g->ptr, smtp_out);
4483 (void) string_from_gstring(g);
4484 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4485 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4486 debug_printf("SMTP>> %s", g->s);
4488 fl.helo_seen = TRUE;
4490 /* Reset the protocol and the state, abandoning any previous message. */
4492 (sender_host_address ? protocols : protocols_local)
4494 ? pextend + (sender_host_authenticated ? pauthed : 0)
4496 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4498 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4499 reset_point = smtp_reset(reset_point);
4501 break; /* HELO/EHLO */
4504 /* The MAIL command requires an address as an operand. All we do
4505 here is to parse it for syntactic correctness. The form "<>" is
4506 a special case which converts into an empty string. The start/end
4507 pointers in the original are not used further for this address, as
4508 it is the canonical extracted address which is all that is kept. */
4512 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4513 was_rej_mail = TRUE; /* Reset if accepted */
4514 env_mail_type_t * mail_args; /* Sanity check & validate args */
4516 if (fl.helo_required && !fl.helo_seen)
4518 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4519 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4520 "HELO/EHLO given", host_and_ident(FALSE));
4526 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4527 US"sender already given");
4531 if (!*smtp_cmd_data)
4533 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4534 US"MAIL must have an address operand");
4538 /* Check to see if the limit for messages per connection would be
4539 exceeded by accepting further messages. */
4541 if (smtp_accept_max_per_connection > 0 &&
4542 smtp_mailcmd_count > smtp_accept_max_per_connection)
4544 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4545 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4546 "messages in one connection", host_and_ident(TRUE));
4550 /* Reset for start of message - even if this is going to fail, we
4551 obviously need to throw away any previous data. */
4553 cancel_cutthrough_connection(TRUE, US"MAIL received");
4554 reset_point = smtp_reset(reset_point);
4556 sender_data = recipient_data = NULL;
4558 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4560 if (fl.esmtp) for(;;)
4562 uschar *name, *value, *end;
4563 unsigned long int size;
4564 BOOL arg_error = FALSE;
4566 if (!extract_option(&name, &value)) break;
4568 for (mail_args = env_mail_type_list;
4569 mail_args->value != ENV_MAIL_OPT_NULL;
4572 if (strcmpic(name, mail_args->name) == 0)
4574 if (mail_args->need_value && strcmpic(value, US"") == 0)
4577 switch(mail_args->value)
4579 /* Handle SIZE= by reading the value. We don't do the check till later,
4580 in order to be able to log the sender address on failure. */
4581 case ENV_MAIL_OPT_SIZE:
4582 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4584 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4586 message_size = (int)size;
4592 /* If this session was initiated with EHLO and accept_8bitmime is set,
4593 Exim will have indicated that it supports the BODY=8BITMIME option. In
4594 fact, it does not support this according to the RFCs, in that it does not
4595 take any special action for forwarding messages containing 8-bit
4596 characters. That is why accept_8bitmime is not the default setting, but
4597 some sites want the action that is provided. We recognize both "8BITMIME"
4598 and "7BIT" as body types, but take no action. */
4599 case ENV_MAIL_OPT_BODY:
4600 if (accept_8bitmime) {
4601 if (strcmpic(value, US"8BITMIME") == 0)
4603 else if (strcmpic(value, US"7BIT") == 0)
4608 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4609 US"invalid data for BODY");
4612 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4618 /* Handle the two DSN options, but only if configured to do so (which
4619 will have caused "DSN" to be given in the EHLO response). The code itself
4620 is included only if configured in at build time. */
4622 case ENV_MAIL_OPT_RET:
4623 if (fl.dsn_advertised)
4625 /* Check if RET has already been set */
4628 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4629 US"RET can be specified once only");
4632 dsn_ret = strcmpic(value, US"HDRS") == 0
4634 : strcmpic(value, US"FULL") == 0
4637 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4638 /* Check for invalid invalid value, and exit with error */
4641 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4642 US"Value for RET is invalid");
4647 case ENV_MAIL_OPT_ENVID:
4648 if (fl.dsn_advertised)
4650 /* Check if the dsn envid has been already set */
4653 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4654 US"ENVID can be specified once only");
4657 dsn_envid = string_copy(value);
4658 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4662 /* Handle the AUTH extension. If the value given is not "<>" and either
4663 the ACL says "yes" or there is no ACL but the sending host is
4664 authenticated, we set it up as the authenticated sender. However, if the
4665 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4666 the condition is met. The value of AUTH is an xtext, which means that +,
4667 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4669 case ENV_MAIL_OPT_AUTH:
4670 if (Ustrcmp(value, "<>") != 0)
4675 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4677 /* Put back terminator overrides for error message */
4680 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4681 US"invalid data for AUTH");
4684 if (!acl_smtp_mailauth)
4686 ignore_msg = US"client not authenticated";
4687 rc = sender_host_authenticated ? OK : FAIL;
4691 ignore_msg = US"rejected by ACL";
4692 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4693 &user_msg, &log_msg);
4699 if (authenticated_by == NULL ||
4700 authenticated_by->mail_auth_condition == NULL ||
4701 expand_check_condition(authenticated_by->mail_auth_condition,
4702 authenticated_by->name, US"authenticator"))
4703 break; /* Accept the AUTH */
4705 ignore_msg = US"server_mail_auth_condition failed";
4706 if (authenticated_id != NULL)
4707 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4708 ignore_msg, authenticated_id);
4713 authenticated_sender = NULL;
4714 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4715 value, host_and_ident(TRUE), ignore_msg);
4718 /* Should only get DEFER or ERROR here. Put back terminator
4719 overrides for error message */
4724 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4731 #ifndef DISABLE_PRDR
4732 case ENV_MAIL_OPT_PRDR:
4734 prdr_requested = TRUE;
4739 case ENV_MAIL_OPT_UTF8:
4740 if (!fl.smtputf8_advertised)
4742 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4743 US"SMTPUTF8 used when not advertised");
4747 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4748 message_smtputf8 = allow_utf8_domains = TRUE;
4749 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4751 int old_pool = store_pool;
4752 store_pool = POOL_PERM;
4753 received_protocol = string_sprintf("utf8%s", received_protocol);
4754 store_pool = old_pool;
4759 /* No valid option. Stick back the terminator characters and break
4760 the loop. Do the name-terminator second as extract_option sets
4761 value==name when it found no equal-sign.
4762 An error for a malformed address will occur. */
4763 case ENV_MAIL_OPT_NULL:
4771 /* Break out of for loop if switch() had bad argument or
4772 when start of the email address is reached */
4773 if (arg_error) break;
4776 /* If we have passed the threshold for rate limiting, apply the current
4777 delay, and update it for next time, provided this is a limited host. */
4779 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4780 verify_check_host(&smtp_ratelimit_hosts) == OK)
4782 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4783 smtp_delay_mail/1000.0);
4784 millisleep((int)smtp_delay_mail);
4785 smtp_delay_mail *= smtp_rlm_factor;
4786 if (smtp_delay_mail > (double)smtp_rlm_limit)
4787 smtp_delay_mail = (double)smtp_rlm_limit;
4790 /* Now extract the address, first applying any SMTP-time rewriting. The
4791 TRUE flag allows "<>" as a sender address. */
4793 raw_sender = rewrite_existflags & rewrite_smtp
4794 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4795 global_rewrite_rules)
4799 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4804 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4808 sender_address = raw_sender;
4810 /* If there is a configured size limit for mail, check that this message
4811 doesn't exceed it. The check is postponed to this point so that the sender
4814 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4816 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4817 log_write(L_size_reject,
4818 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4819 "message too big: size%s=%d max=%d",
4821 host_and_ident(TRUE),
4822 (message_size == INT_MAX)? ">" : "",
4824 thismessage_size_limit);
4825 sender_address = NULL;
4829 /* Check there is enough space on the disk unless configured not to.
4830 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4831 plus the current message - i.e. we accept the message only if it won't
4832 reduce the space below the threshold. Add 5000 to the size to allow for
4833 overheads such as the Received: line and storing of recipients, etc.
4834 By putting the check here, even when SIZE is not given, it allow VRFY
4835 and EXPN etc. to be used when space is short. */
4837 if (!receive_check_fs(
4838 smtp_check_spool_space && message_size >= 0
4839 ? message_size + 5000 : 0))
4841 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4842 sender_address = NULL;
4846 /* If sender_address is unqualified, reject it, unless this is a locally
4847 generated message, or the sending host or net is permitted to send
4848 unqualified addresses - typically local machines behaving as MUAs -
4849 in which case just qualify the address. The flag is set above at the start
4850 of the SMTP connection. */
4852 if (!sender_domain && *sender_address)
4853 if (f.allow_unqualified_sender)
4855 sender_domain = Ustrlen(sender_address) + 1;
4856 sender_address = rewrite_address_qualify(sender_address, FALSE);
4857 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4862 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4864 log_write(L_smtp_syntax_error,
4865 LOG_MAIN|LOG_REJECT,
4866 "unqualified sender rejected: <%s> %s%s",
4868 host_and_ident(TRUE),
4870 sender_address = NULL;
4874 /* Apply an ACL check if one is defined, before responding. Afterwards,
4875 when pipelining is not advertised, do another sync check in case the ACL
4876 delayed and the client started sending in the meantime. */
4880 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4881 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4887 if (rc == OK || rc == DISCARD)
4889 BOOL more = pipeline_response();
4892 smtp_printf("%s%s%s", more, US"250 OK",
4893 #ifndef DISABLE_PRDR
4894 prdr_requested ? US", PRDR Requested" : US"",
4901 #ifndef DISABLE_PRDR
4903 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4905 smtp_user_msg(US"250", user_msg);
4907 smtp_delay_rcpt = smtp_rlr_base;
4908 f.recipients_discarded = (rc == DISCARD);
4909 was_rej_mail = FALSE;
4913 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4914 sender_address = NULL;
4919 /* The RCPT command requires an address as an operand. There may be any
4920 number of RCPT commands, specifying multiple recipients. We build them all
4921 into a data structure. The start/end values given by parse_extract_address
4922 are not used, as we keep only the extracted address. */
4927 was_rcpt = fl.rcpt_in_progress = TRUE;
4929 /* There must be a sender address; if the sender was rejected and
4930 pipelining was advertised, we assume the client was pipelining, and do not
4931 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4932 get the same treatment. */
4934 if (sender_address == NULL)
4936 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4938 smtp_printf("503 sender not yet given\r\n", FALSE);
4939 was_rej_mail = TRUE;
4943 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4944 US"sender not yet given");
4945 was_rcpt = FALSE; /* Not a valid RCPT */
4951 /* Check for an operand */
4953 if (smtp_cmd_data[0] == 0)
4955 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4956 US"RCPT must have an address operand");
4961 /* Set the DSN flags orcpt and dsn_flags from the session*/
4965 if (fl.esmtp) for(;;)
4967 uschar *name, *value;
4969 if (!extract_option(&name, &value))
4972 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4974 /* Check whether orcpt has been already set */
4977 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4978 US"ORCPT can be specified once only");
4981 orcpt = string_copy(value);
4982 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4985 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4987 /* Check if the notify flags have been already set */
4990 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4991 US"NOTIFY can be specified once only");
4994 if (strcmpic(value, US"NEVER") == 0)
4995 dsn_flags |= rf_notify_never;
5002 while (*pp != 0 && *pp != ',') pp++;
5003 if (*pp == ',') *pp++ = 0;
5004 if (strcmpic(p, US"SUCCESS") == 0)
5006 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5007 dsn_flags |= rf_notify_success;
5009 else if (strcmpic(p, US"FAILURE") == 0)
5011 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5012 dsn_flags |= rf_notify_failure;
5014 else if (strcmpic(p, US"DELAY") == 0)
5016 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5017 dsn_flags |= rf_notify_delay;
5021 /* Catch any strange values */
5022 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5023 US"Invalid value for NOTIFY parameter");
5028 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5032 /* Unknown option. Stick back the terminator characters and break
5033 the loop. An error for a malformed address will occur. */
5037 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5044 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5045 as a recipient address */
5047 recipient = rewrite_existflags & rewrite_smtp
5048 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5049 global_rewrite_rules)
5052 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5053 &recipient_domain, FALSE)))
5055 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5060 /* If the recipient address is unqualified, reject it, unless this is a
5061 locally generated message. However, unqualified addresses are permitted
5062 from a configured list of hosts and nets - typically when behaving as
5063 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5064 really. The flag is set at the start of the SMTP connection.
5066 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5067 assumed this meant "reserved local part", but the revision of RFC 821 and
5068 friends now makes it absolutely clear that it means *mailbox*. Consequently
5069 we must always qualify this address, regardless. */
5071 if (!recipient_domain)
5072 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5079 /* Check maximum allowed */
5081 if (rcpt_count > recipients_max && recipients_max > 0)
5083 if (recipients_max_reject)
5086 smtp_printf("552 too many recipients\r\n", FALSE);
5088 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5089 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5094 smtp_printf("452 too many recipients\r\n", FALSE);
5096 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5097 "temporarily rejected: sender=<%s> %s", sender_address,
5098 host_and_ident(TRUE));
5105 /* If we have passed the threshold for rate limiting, apply the current
5106 delay, and update it for next time, provided this is a limited host. */
5108 if (rcpt_count > smtp_rlr_threshold &&
5109 verify_check_host(&smtp_ratelimit_hosts) == OK)
5111 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5112 smtp_delay_rcpt/1000.0);
5113 millisleep((int)smtp_delay_rcpt);
5114 smtp_delay_rcpt *= smtp_rlr_factor;
5115 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5116 smtp_delay_rcpt = (double)smtp_rlr_limit;
5119 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5120 for them. Otherwise, check the access control list for this recipient. As
5121 there may be a delay in this, re-check for a synchronization error
5122 afterwards, unless pipelining was advertised. */
5124 if (f.recipients_discarded)
5127 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5129 && !f.smtp_in_pipelining_advertised && !check_sync())
5132 /* The ACL was happy */
5136 BOOL more = pipeline_response();
5139 smtp_user_msg(US"250", user_msg);
5141 smtp_printf("250 Accepted\r\n", more);
5142 receive_add_recipient(recipient, -1);
5144 /* Set the dsn flags in the recipients_list */
5145 recipients_list[recipients_count-1].orcpt = orcpt;
5146 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5148 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5149 recipients_list[recipients_count-1].orcpt,
5150 recipients_list[recipients_count-1].dsn_flags); */
5153 /* The recipient was discarded */
5155 else if (rc == DISCARD)
5158 smtp_user_msg(US"250", user_msg);
5160 smtp_printf("250 Accepted\r\n", FALSE);
5163 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5164 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5165 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5166 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5167 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5170 /* Either the ACL failed the address, or it was deferred. */
5174 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5175 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5180 /* The DATA command is legal only if it follows successful MAIL FROM
5181 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5182 not counted as a protocol error if it follows RCPT (which must have been
5183 rejected if there are no recipients.) This function is complete when a
5184 valid DATA command is encountered.
5186 Note concerning the code used: RFC 2821 says this:
5188 - If there was no MAIL, or no RCPT, command, or all such commands
5189 were rejected, the server MAY return a "command out of sequence"
5190 (503) or "no valid recipients" (554) reply in response to the
5193 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5194 because it is the same whether pipelining is in use or not.
5196 If all the RCPT commands that precede DATA provoked the same error message
5197 (often indicating some kind of system error), it is helpful to include it
5198 with the DATA rejection (an idea suggested by Tony Finch). */
5205 if (chunking_state != CHUNKING_OFFERED)
5207 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5208 US"BDAT command used when CHUNKING not advertised");
5212 /* grab size, endmarker */
5214 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5216 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5217 US"missing size for BDAT command");
5220 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5221 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5222 chunking_data_left = chunking_datasize;
5223 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5224 (int)chunking_state, chunking_data_left);
5226 /* push the current receive_* function on the "stack", and
5227 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5228 functions to do the dirty work. */
5229 lwr_receive_getc = receive_getc;
5230 lwr_receive_getbuf = receive_getbuf;
5231 lwr_receive_ungetc = receive_ungetc;
5233 receive_getc = bdat_getc;
5234 receive_ungetc = bdat_ungetc;
5245 DATA_BDAT: /* Common code for DATA and BDAT */
5246 #ifndef DISABLE_PIPE_CONNECT
5247 fl.pipe_connect_acceptable = FALSE;
5249 if (!discarded && recipients_count <= 0)
5251 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5253 uschar *code = US"503";
5254 int len = Ustrlen(rcpt_smtp_response);
5255 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5257 /* Responses from smtp_printf() will have \r\n on the end */
5258 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5259 rcpt_smtp_response[len-2] = 0;
5260 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5262 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5263 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5264 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5266 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5267 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5268 ? US"valid RCPT command must precede DATA"
5269 : US"valid RCPT command must precede BDAT");
5271 if (chunking_state > CHUNKING_OFFERED)
5276 if (toomany && recipients_max_reject)
5278 sender_address = NULL; /* This will allow a new MAIL without RSET */
5279 sender_address_unrewritten = NULL;
5280 smtp_printf("554 Too many recipients\r\n", FALSE);
5284 if (chunking_state > CHUNKING_OFFERED)
5285 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5288 /* If there is an ACL, re-check the synchronization afterwards, since the
5289 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5290 to get the DATA command sent. */
5292 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5296 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5297 f.enable_dollar_recipients = TRUE;
5298 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5300 f.enable_dollar_recipients = FALSE;
5301 if (rc == OK && !check_sync())
5305 { /* Either the ACL failed the address, or it was deferred. */
5306 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5312 smtp_user_msg(US"354", user_msg);
5315 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5319 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5320 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5321 US &on, sizeof(on));
5324 message_ended = END_NOTENDED; /* Indicate in middle of data */
5335 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5336 &start, &end, &recipient_domain, FALSE)))
5338 smtp_printf("501 %s\r\n", FALSE, errmess);
5342 if (!recipient_domain)
5343 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5347 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5348 &user_msg, &log_msg)) != OK)
5349 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5353 address_item * addr = deliver_make_addr(address, FALSE);
5355 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5356 -1, -1, NULL, NULL, NULL))
5359 s = string_sprintf("250 <%s> is deliverable", address);
5363 s = (addr->user_message != NULL)?
5364 string_sprintf("451 <%s> %s", address, addr->user_message) :
5365 string_sprintf("451 Cannot resolve <%s> at this time", address);
5369 s = (addr->user_message != NULL)?
5370 string_sprintf("550 <%s> %s", address, addr->user_message) :
5371 string_sprintf("550 <%s> is not deliverable", address);
5372 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5373 smtp_cmd_argument, host_and_ident(TRUE));
5377 smtp_printf("%s\r\n", FALSE, s);
5385 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5387 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5390 BOOL save_log_testing_mode = f.log_testing_mode;
5391 f.address_test_mode = f.log_testing_mode = TRUE;
5392 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5393 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5395 f.address_test_mode = FALSE;
5396 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5405 if (!fl.tls_advertised)
5407 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5408 US"STARTTLS command used when not advertised");
5412 /* Apply an ACL check if one is defined */
5414 if ( acl_smtp_starttls
5415 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5416 &user_msg, &log_msg)) != OK
5419 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5423 /* RFC 2487 is not clear on when this command may be sent, though it
5424 does state that all information previously obtained from the client
5425 must be discarded if a TLS session is started. It seems reasonable to
5426 do an implied RSET when STARTTLS is received. */
5428 incomplete_transaction_log(US"STARTTLS");
5429 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5430 reset_point = smtp_reset(reset_point);
5432 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5434 /* There's an attack where more data is read in past the STARTTLS command
5435 before TLS is negotiated, then assumed to be part of the secure session
5436 when used afterwards; we use segregated input buffers, so are not
5437 vulnerable, but we want to note when it happens and, for sheer paranoia,
5438 ensure that the buffer is "wiped".
5439 Pipelining sync checks will normally have protected us too, unless disabled
5440 by configuration. */
5442 if (receive_smtp_buffered())
5445 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5446 if (tls_in.active.sock < 0)
5447 smtp_inend = smtp_inptr = smtp_inbuffer;
5448 /* and if TLS is already active, tls_server_start() should fail */
5451 /* There is nothing we value in the input buffer and if TLS is successfully
5452 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5453 fresh content into it. The buffer contains arbitrary content from an
5454 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5455 It seems safest to just wipe away the content rather than leave it as a
5456 target to jump to. */
5458 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5460 /* Attempt to start up a TLS session, and if successful, discard all
5461 knowledge that was obtained previously. At least, that's what the RFC says,
5462 and that's what happens by default. However, in order to work round YAEB,
5463 there is an option to remember the esmtp state. Sigh.
5465 We must allow for an extra EHLO command and an extra AUTH command after
5466 STARTTLS that don't add to the nonmail command count. */
5469 if ((rc = tls_server_start(&s)) == OK)
5471 if (!tls_remember_esmtp)
5472 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5473 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5474 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5475 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5476 if (sender_helo_name)
5478 sender_helo_name = NULL;
5479 host_build_sender_fullhost(); /* Rebuild */
5480 set_process_info("handling incoming TLS connection from %s",
5481 host_and_ident(FALSE));
5484 (sender_host_address ? protocols : protocols_local)
5486 ? pextend + (sender_host_authenticated ? pauthed : 0)
5488 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5491 sender_host_auth_pubname = sender_host_authenticated = NULL;
5492 authenticated_id = NULL;
5493 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5494 DEBUG(D_tls) debug_printf("TLS active\n");
5495 break; /* Successful STARTTLS */
5498 (void) smtp_log_tls_fail(s);
5500 /* Some local configuration problem was discovered before actually trying
5501 to do a TLS handshake; give a temporary error. */
5505 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5509 /* Hard failure. Reject everything except QUIT or closed connection. One
5510 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5511 set, but we must still reject all incoming commands. Another is a handshake
5512 failure - and there may some encrypted data still in the pipe to us, which we
5513 see as garbage commands. */
5515 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5516 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5519 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5520 smtp_get_connection_info());
5521 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5525 /* It is perhaps arguable as to which exit ACL should be called here,
5526 but as it is probably a situation that almost never arises, it
5527 probably doesn't matter. We choose to call the real QUIT ACL, which in
5528 some sense is perhaps "right". */
5531 f.smtp_in_quit = TRUE;
5534 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5535 &log_msg)) == ERROR))
5536 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5539 smtp_respond(US"221", 3, TRUE, user_msg);
5541 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5542 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5543 smtp_get_connection_info());
5548 smtp_printf("554 Security failure\r\n", FALSE);
5551 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5556 /* The ACL for QUIT is provided for gathering statistical information or
5557 similar; it does not affect the response code, but it can supply a custom
5561 smtp_quit_handler(&user_msg, &log_msg);
5567 smtp_rset_handler();
5568 cancel_cutthrough_connection(TRUE, US"RSET received");
5569 reset_point = smtp_reset(reset_point);
5576 smtp_printf("250 OK\r\n", FALSE);
5580 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5581 used, a check will be done for permitted hosts. Show STARTTLS only if not
5582 already in a TLS session and if it would be advertised in the EHLO
5587 smtp_printf("214-Commands supported:\r\n", TRUE);
5591 Ustrcat(buffer, US" AUTH");
5593 if (tls_in.active.sock < 0 &&
5594 verify_check_host(&tls_advertise_hosts) != FAIL)
5595 Ustrcat(buffer, US" STARTTLS");
5597 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5598 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5599 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5600 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5601 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5602 smtp_printf("214%s\r\n", FALSE, buffer);
5608 incomplete_transaction_log(US"connection lost");
5609 smtp_notquit_exit(US"connection-lost", US"421",
5610 US"%s lost input connection", smtp_active_hostname);
5612 /* Don't log by default unless in the middle of a message, as some mailers
5613 just drop the call rather than sending QUIT, and it clutters up the logs.
5616 if (sender_address || recipients_count > 0)
5617 log_write(L_lost_incoming_connection, LOG_MAIN,
5618 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5619 f.sender_host_unknown ? "EOF" : "disconnection",
5620 f.tcp_in_fastopen_logged
5623 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5625 host_and_ident(FALSE), smtp_read_error,
5626 string_timesince(&smtp_connection_start)
5630 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5631 smtp_get_connection_info(),
5632 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5634 string_timesince(&smtp_connection_start)
5645 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5646 US"ETRN is not permitted inside a transaction");
5650 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5651 host_and_ident(FALSE));
5653 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5654 &user_msg, &log_msg)) != OK)
5656 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5660 /* Compute the serialization key for this command. */
5662 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5664 /* If a command has been specified for running as a result of ETRN, we
5665 permit any argument to ETRN. If not, only the # standard form is permitted,
5666 since that is strictly the only kind of ETRN that can be implemented
5667 according to the RFC. */
5669 if (smtp_etrn_command)
5673 etrn_command = smtp_etrn_command;
5674 deliver_domain = smtp_cmd_data;
5675 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5676 US"ETRN processing", &error);
5677 deliver_domain = NULL;
5680 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5682 smtp_printf("458 Internal failure\r\n", FALSE);
5687 /* Else set up to call Exim with the -R option. */
5691 if (*smtp_cmd_data++ != '#')
5693 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5694 US"argument must begin with #");
5697 etrn_command = US"exim -R";
5698 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5699 *queue_name ? 4 : 2,
5700 US"-R", smtp_cmd_data,
5701 US"-MCG", queue_name);
5704 /* If we are host-testing, don't actually do anything. */
5710 debug_printf("ETRN command is: %s\n", etrn_command);
5711 debug_printf("ETRN command execution skipped\n");
5713 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5714 else smtp_user_msg(US"250", user_msg);
5719 /* If ETRN queue runs are to be serialized, check the database to
5720 ensure one isn't already running. */
5722 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5724 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5728 /* Fork a child process and run the command. We don't want to have to
5729 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5730 forking. It should be set that way anyway for external incoming SMTP,
5731 but we save and restore to be tidy. If serialization is required, we
5732 actually run the command in yet another process, so we can wait for it
5733 to complete and then remove the serialization lock. */
5735 oldsignal = signal(SIGCHLD, SIG_IGN);
5737 if ((pid = exim_fork(US"etrn-command")) == 0)
5739 smtp_input = FALSE; /* This process is not associated with the */
5740 (void)fclose(smtp_in); /* SMTP call any more. */
5741 (void)fclose(smtp_out);
5743 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5745 /* If not serializing, do the exec right away. Otherwise, fork down
5746 into another process. */
5748 if ( !smtp_etrn_serialize
5749 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5751 DEBUG(D_exec) debug_print_argv(argv);
5752 exim_nullstd(); /* Ensure std{in,out,err} exist */
5753 execv(CS argv[0], (char *const *)argv);
5754 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5755 etrn_command, strerror(errno));
5756 _exit(EXIT_FAILURE); /* paranoia */
5759 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5760 is, we are in the first subprocess, after forking again. All we can do
5761 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5762 complete, before removing the serialization. */
5765 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5766 "failed: %s", strerror(errno));
5770 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5772 (void)wait(&status);
5773 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5777 enq_end(etrn_serialize_key);
5778 exim_underbar_exit(EXIT_SUCCESS);
5781 /* Back in the top level SMTP process. Check that we started a subprocess
5782 and restore the signal state. */
5786 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5788 smtp_printf("458 Unable to fork process\r\n", FALSE);
5789 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5793 smtp_printf("250 OK\r\n", FALSE);
5795 smtp_user_msg(US"250", user_msg);
5797 signal(SIGCHLD, oldsignal);
5802 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5803 US"unexpected argument data");
5807 /* This currently happens only for NULLs, but could be extended. */
5810 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5811 US"NUL character(s) present (shown as '?')");
5812 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5819 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5820 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5821 c = smtp_inend - smtp_inptr;
5822 if (c > 150) c = 150; /* limit logged amount */
5824 incomplete_transaction_log(US"sync failure");
5825 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5826 "(next input sent too soon: pipelining was%s advertised): "
5827 "rejected \"%s\" %s next input=\"%s\"",
5828 f.smtp_in_pipelining_advertised ? "" : " not",
5829 smtp_cmd_buffer, host_and_ident(TRUE),
5830 string_printing(smtp_inptr));
5831 smtp_notquit_exit(US"synchronization-error", US"554",
5832 US"SMTP synchronization error");
5833 done = 1; /* Pretend eof - drops connection */
5837 case TOO_MANY_NONMAIL_CMD:
5838 s = smtp_cmd_buffer;
5839 while (*s != 0 && !isspace(*s)) s++;
5840 incomplete_transaction_log(US"too many non-mail commands");
5841 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5842 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5843 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5844 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5845 done = 1; /* Pretend eof - drops connection */
5848 #ifdef SUPPORT_PROXY
5849 case PROXY_FAIL_IGNORE_CMD:
5850 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5855 if (unknown_command_count++ >= smtp_max_unknown_commands)
5857 log_write(L_smtp_syntax_error, LOG_MAIN,
5858 "SMTP syntax error in \"%s\" %s %s",
5859 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5860 US"unrecognized command");
5861 incomplete_transaction_log(US"unrecognized command");
5862 smtp_notquit_exit(US"bad-commands", US"500",
5863 US"Too many unrecognized commands");
5865 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5866 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5867 string_printing(smtp_cmd_buffer));
5870 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5871 US"unrecognized command");
5875 /* This label is used by goto's inside loops that want to break out to
5876 the end of the command-processing loop. */
5879 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5880 last_was_rcpt = was_rcpt; /* protocol error handling */
5884 return done - 2; /* Convert yield values */
5890 authres_smtpauth(gstring * g)
5892 if (!sender_host_authenticated)
5895 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5897 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5898 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5899 else if (authenticated_id)
5900 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5902 g = string_catn(g, US") reason=x509.auth", 17);
5904 if (authenticated_sender)
5905 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5913 /* End of smtp_in.c */