1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 static uschar *smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Recheck synchronization *
324 *************************************************/
326 /* Synchronization checks can never be perfect because a packet may be on its
327 way but not arrived when the check is done. Normally, the checks happen when
328 commands are read: Exim ensures that there is no more input in the input buffer.
329 In normal cases, the response to the command will be fast, and there is no
332 However, for some commands an ACL is run, and that can include delays. In those
333 cases, it is useful to do another check on the input just before sending the
334 response. This also applies at the start of a connection. This function does
335 that check by means of the select() function, as long as the facility is not
336 disabled or inappropriate. A failure of select() is ignored.
338 When there is unwanted input, we read it so that it appears in the log of the
342 Returns: TRUE if all is well; FALSE if there is input pending
346 wouldblock_reading(void)
350 struct timeval tzero;
353 if (tls_in.active.sock >= 0)
354 return !tls_could_read();
357 if (smtp_inptr < smtp_inend)
360 fd = fileno(smtp_in);
365 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
367 if (rc <= 0) return TRUE; /* Not ready to read */
368 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
369 if (rc < 0) return TRUE; /* End of file or error */
378 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
381 return wouldblock_reading();
385 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
386 a reponse with the one following. */
389 pipeline_response(void)
391 if ( !smtp_enforce_sync || !sender_host_address
392 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
395 if (wouldblock_reading()) return FALSE;
396 f.smtp_in_pipelining_used = TRUE;
401 #ifndef DISABLE_PIPE_CONNECT
403 pipeline_connect_sends(void)
405 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
408 if (wouldblock_reading()) return FALSE;
409 f.smtp_in_early_pipe_used = TRUE;
414 /*************************************************
415 * Log incomplete transactions *
416 *************************************************/
418 /* This function is called after a transaction has been aborted by RSET, QUIT,
419 connection drops or other errors. It logs the envelope information received
420 so far in order to preserve address verification attempts.
422 Argument: string to indicate what aborted the transaction
427 incomplete_transaction_log(uschar *what)
429 if (!sender_address /* No transaction in progress */
430 || !LOGGING(smtp_incomplete_transaction))
433 /* Build list of recipients for logging */
435 if (recipients_count > 0)
437 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
438 for (int i = 0; i < recipients_count; i++)
439 raw_recipients[i] = recipients_list[i].address;
440 raw_recipients_count = recipients_count;
443 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
444 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
451 smtp_command_timeout_exit(void)
453 log_write(L_lost_incoming_connection,
454 LOG_MAIN, "SMTP command timeout on%s connection from %s",
455 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
456 if (smtp_batched_input)
457 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
458 smtp_notquit_exit(US"command-timeout", US"421",
459 US"%s: SMTP command timeout - closing connection",
460 smtp_active_hostname);
461 exim_exit(EXIT_FAILURE);
465 smtp_command_sigterm_exit(void)
467 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
468 if (smtp_batched_input)
469 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
470 smtp_notquit_exit(US"signal-exit", US"421",
471 US"%s: Service not available - closing connection", smtp_active_hostname);
472 exim_exit(EXIT_FAILURE);
476 smtp_data_timeout_exit(void)
478 log_write(L_lost_incoming_connection,
479 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
480 sender_fullhost ? sender_fullhost : US"local process", sender_address);
481 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
482 /* Does not return */
486 smtp_data_sigint_exit(void)
488 log_write(0, LOG_MAIN, "%s closed after %s",
489 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
490 receive_bomb_out(US"signal-exit",
491 US"Service not available - SIGTERM or SIGINT received");
492 /* Does not return */
497 /* Refill the buffer, and notify DKIM verification code.
498 Return false for error or EOF.
502 smtp_refill(unsigned lim)
505 if (!smtp_out) return FALSE;
507 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
509 /* Limit amount read, so non-message data is not fed to DKIM.
510 Take care to not touch the safety NUL at the end of the buffer. */
512 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
514 if (smtp_receive_timeout > 0) ALARM_CLR(0);
517 /* Must put the error text in fixed store, because this might be during
518 header reading, where it releases unused store above the header. */
521 if (had_command_timeout) /* set by signal handler */
522 smtp_command_timeout_exit(); /* does not return */
523 if (had_command_sigterm)
524 smtp_command_sigterm_exit();
525 if (had_data_timeout)
526 smtp_data_timeout_exit();
528 smtp_data_sigint_exit();
530 smtp_had_error = save_errno;
531 smtp_read_error = string_copy_perm(
532 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
539 dkim_exim_verify_feed(smtp_inbuffer, rc);
541 smtp_inend = smtp_inbuffer + rc;
542 smtp_inptr = smtp_inbuffer;
546 /*************************************************
547 * SMTP version of getc() *
548 *************************************************/
550 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
551 it flushes the output, and refills the buffer, with a timeout. The signal
552 handler is set appropriately by the calling function. This function is not used
553 after a connection has negotiated itself into an TLS/SSL state.
555 Arguments: lim Maximum amount to read/buffer
556 Returns: the next character or EOF
560 smtp_getc(unsigned lim)
562 if (smtp_inptr >= smtp_inend)
563 if (!smtp_refill(lim))
565 return *smtp_inptr++;
569 smtp_getbuf(unsigned * len)
574 if (smtp_inptr >= smtp_inend)
575 if (!smtp_refill(*len))
576 { *len = 0; return NULL; }
578 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
589 int n = smtp_inend - smtp_inptr;
591 dkim_exim_verify_feed(smtp_inptr, n);
596 /* 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 * Restore socket timeout to previous value *
1038 *************************************************/
1039 /* If the previous value was successfully retrieved, restore
1040 it before returning control to the non-proxy routines
1042 Arguments: fd - File descriptor for input
1043 get_ok - Successfully retrieved previous values
1044 tvtmp - Time struct with previous values
1045 vslen - Length of time struct
1049 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1052 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1055 /*************************************************
1056 * Check if host is required proxy host *
1057 *************************************************/
1058 /* The function determines if inbound host will be a regular smtp host
1059 or if it is configured that it must use Proxy Protocol. A local
1067 check_proxy_protocol_host()
1071 if ( sender_host_address
1072 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1073 sender_host_address, NULL)) == OK)
1076 debug_printf("Detected proxy protocol configured host\n");
1077 proxy_session = TRUE;
1079 return proxy_session;
1083 /*************************************************
1084 * Read data until newline or end of buffer *
1085 *************************************************/
1086 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1087 read an entire buffer and assume there will be nothing past a proxy protocol
1088 header. Our approach normally is to use stdio, but again that relies upon
1089 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1090 reading _nothing_ before client TLS handshake. So we don't want to use the
1091 usual buffering reads which may read enough to block TLS starting.
1093 So unfortunately we're down to "read one byte at a time, with a syscall each,
1094 and expect a little overhead", for all proxy-opened connections which are v1,
1095 just to handle the TLS-on-connect case. Since SSL functions wrap the
1096 underlying fd, we can't assume that we can feed them any already-read content.
1098 We need to know where to read to, the max capacity, and we'll read until we
1099 get a CR and one more character. Let the caller scream if it's CR+!LF.
1101 Return the amount read.
1105 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1107 uschar *to = base + already;
1113 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1114 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1116 cr = memchr(base, '\r', already);
1119 if ((cr - base) < already - 1)
1121 /* \r and presumed \n already within what we have; probably not
1122 actually proxy protocol, but abort cleanly. */
1125 /* \r is last character read, just need one more. */
1129 while (capacity > 0)
1131 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1143 /* reached end without having room for a final newline, abort */
1148 /*************************************************
1149 * Setup host for proxy protocol *
1150 *************************************************/
1151 /* The function configures the connection based on a header from the
1152 inbound host to use Proxy Protocol. The specification is very exact
1153 so exit with an error if do not find the exact required pieces. This
1154 includes an incorrect number of spaces separating args.
1157 Returns: Boolean success
1161 setup_proxy_protocol_host()
1173 struct { /* TCP/UDP over IPv4, len = 12 */
1179 struct { /* TCP/UDP over IPv6, len = 36 */
1180 uint8_t src_addr[16];
1181 uint8_t dst_addr[16];
1185 struct { /* AF_UNIX sockets, len = 216 */
1186 uschar src_addr[108];
1187 uschar dst_addr[108];
1193 /* Temp variables used in PPv2 address:port parsing */
1195 char tmpip[INET_ADDRSTRLEN];
1196 struct sockaddr_in tmpaddr;
1197 char tmpip6[INET6_ADDRSTRLEN];
1198 struct sockaddr_in6 tmpaddr6;
1200 /* We can't read "all data until end" because while SMTP is
1201 server-speaks-first, the TLS handshake is client-speaks-first, so for
1202 TLS-on-connect ports the proxy protocol header will usually be immediately
1203 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1204 reinject data for reading by those. So instead we first read "enough to be
1205 safely read within the header, and figure out how much more to read".
1206 For v1 we will later read to the end-of-line, for v2 we will read based upon
1209 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1210 data is needed total. For v1, where the line looks like:
1211 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1213 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1214 We seem to support that. So, if we read 14 octets then we can tell if we're
1215 v2 or v1. If we're v1, we can continue reading as normal.
1217 If we're v2, we can't slurp up the entire header. We need the length in the
1218 15th & 16th octets, then to read everything after that.
1220 So to safely handle v1 and v2, with client-sent-first supported correctly,
1221 we have to do a minimum of 3 read calls, not 1. Eww.
1224 #define PROXY_INITIAL_READ 14
1225 #define PROXY_V2_HEADER_SIZE 16
1226 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1227 # error Code bug in sizes of data to read for proxy usage
1232 int fd = fileno(smtp_in);
1233 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1234 uschar * iptype; /* To display debug info */
1236 struct timeval tvtmp;
1237 socklen_t vslen = sizeof(struct timeval);
1240 /* Save current socket timeout values */
1241 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1243 /* Proxy Protocol host must send header within a short time
1244 (default 3 seconds) or it's considered invalid */
1245 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1246 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1247 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1252 /* The inbound host was declared to be a Proxy Protocol host, so
1253 don't do a PEEK into the data, actually slurp up enough to be
1254 "safe". Can't take it all because TLS-on-connect clients follow
1255 immediately with TLS handshake. */
1256 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1258 while (ret == -1 && errno == EINTR);
1263 /* For v2, handle reading the length, and then the rest. */
1264 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1269 /* First get the length fields. */
1272 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1273 } while (retmore == -1 && errno == EINTR);
1278 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1280 /* May 2014: haproxy combined the version and command into one byte to
1281 allow two full bytes for the length field in order to proxy SSL
1282 connections. SSL Proxy is not supported in this version of Exim, but
1283 must still separate values here. */
1287 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1291 /* The v2 header will always be 16 bytes per the spec. */
1292 size = 16 + ntohs(hdr.v2.len);
1293 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1294 size, (int)sizeof(hdr));
1296 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1297 amount that we need. Double-check that the size is not unreasonable, then
1299 if (size > sizeof(hdr))
1301 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1309 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1310 } while (retmore == -1 && errno == EINTR);
1314 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1315 } while (ret < size);
1317 } /* end scope for getting rest of data for v2 */
1319 /* At this point: if PROXYv2, we've read the exact size required for all data;
1320 if PROXYv1 then we've read "less than required for any valid line" and should
1323 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1325 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1329 case 0x01: /* PROXY command */
1332 case 0x11: /* TCPv4 address type */
1334 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1335 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1336 if (!string_is_ip_address(US tmpip, 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 tmpip);
1343 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1344 proxy_local_port = sender_host_port;
1345 sender_host_port = tmpport;
1346 /* Save dest ip/port */
1347 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1348 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1349 if (!string_is_ip_address(US tmpip, NULL))
1351 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1354 proxy_external_address = string_copy(US tmpip);
1355 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1356 proxy_external_port = tmpport;
1358 case 0x21: /* TCPv6 address type */
1360 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1361 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1362 if (!string_is_ip_address(US tmpip6, NULL))
1364 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1367 proxy_local_address = sender_host_address;
1368 sender_host_address = string_copy(US tmpip6);
1369 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1370 proxy_local_port = sender_host_port;
1371 sender_host_port = tmpport;
1372 /* Save dest ip/port */
1373 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1374 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1375 if (!string_is_ip_address(US tmpip6, NULL))
1377 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1380 proxy_external_address = string_copy(US tmpip6);
1381 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1382 proxy_external_port = tmpport;
1386 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1390 /* Unsupported protocol, keep local connection address */
1392 case 0x00: /* LOCAL command */
1393 /* Keep local connection address for LOCAL */
1398 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1402 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1406 uschar *sp; /* Utility variables follow */
1411 /* get the rest of the line */
1412 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1417 p = string_copy(hdr.v1.line);
1418 end = memchr(p, '\r', ret - 1);
1420 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1422 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1425 *end = '\0'; /* Terminate the string */
1426 size = end + 2 - p; /* Skip header + CRLF */
1427 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1428 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1429 /* Step through the string looking for the required fields. Ensure
1430 strict adherence to required formatting, exit for any error. */
1432 if (!isspace(*(p++)))
1434 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1437 if (!Ustrncmp(p, CCS"TCP4", 4))
1439 else if (!Ustrncmp(p,CCS"TCP6", 4))
1441 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1443 iptype = US"Unknown";
1448 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1452 p += Ustrlen(iptype);
1453 if (!isspace(*(p++)))
1455 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1458 /* Find the end of the arg */
1459 if ((sp = Ustrchr(p, ' ')) == NULL)
1462 debug_printf("Did not find proxied src %s\n", iptype);
1466 if(!string_is_ip_address(p, NULL))
1469 debug_printf("Proxied src arg is not an %s address\n", iptype);
1472 proxy_local_address = sender_host_address;
1473 sender_host_address = p;
1475 if ((sp = Ustrchr(p, ' ')) == NULL)
1478 debug_printf("Did not find proxy dest %s\n", iptype);
1482 if(!string_is_ip_address(p, NULL))
1485 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1488 proxy_external_address = p;
1490 if ((sp = Ustrchr(p, ' ')) == NULL)
1492 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1496 tmp_port = strtol(CCS p, &endc, 10);
1497 if (*endc || tmp_port == 0)
1500 debug_printf("Proxied src port '%s' not an integer\n", p);
1503 proxy_local_port = sender_host_port;
1504 sender_host_port = tmp_port;
1506 if ((sp = Ustrchr(p, '\0')) == NULL)
1508 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1511 tmp_port = strtol(CCS p, &endc, 10);
1512 if (*endc || tmp_port == 0)
1515 debug_printf("Proxy dest port '%s' not an integer\n", p);
1518 proxy_external_port = tmp_port;
1519 /* Already checked for /r /n above. Good V1 header received. */
1523 /* Wrong protocol */
1524 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1525 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1531 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1532 yield = proxy_session;
1534 /* Don't flush any potential buffer contents. Any input on proxyfail
1535 should cause a synchronization failure */
1538 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1543 sender_host_name = NULL;
1544 (void) host_name_lookup();
1545 host_build_sender_fullhost();
1549 f.proxy_session_failed = TRUE;
1551 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1558 /*************************************************
1559 * Read one command line *
1560 *************************************************/
1562 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1563 There are sites that don't do this, and in any case internal SMTP probably
1564 should check only for LF. Consequently, we check here for LF only. The line
1565 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1566 an unknown command. The command is read into the global smtp_cmd_buffer so that
1567 it is available via $smtp_command.
1569 The character reading routine sets up a timeout for each block actually read
1570 from the input (which may contain more than one command). We set up a special
1571 signal handler that closes down the session on a timeout. Control does not
1572 return when it runs.
1575 check_sync if TRUE, check synchronization rules if global option is TRUE
1576 buffer_lim maximum to buffer in lower layer
1578 Returns: a code identifying the command (enumerated above)
1582 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1586 BOOL hadnull = FALSE;
1588 had_command_timeout = 0;
1589 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1591 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1593 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1595 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1603 smtp_cmd_buffer[ptr++] = c;
1606 receive_linecount++; /* For BSMTP errors */
1607 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1609 /* If hit end of file, return pseudo EOF command. Whether we have a
1610 part-line already read doesn't matter, since this is an error state. */
1612 if (c == EOF) return EOF_CMD;
1614 /* Remove any CR and white space at the end of the line, and terminate the
1617 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1618 smtp_cmd_buffer[ptr] = 0;
1620 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1622 /* NULLs are not allowed in SMTP commands */
1624 if (hadnull) return BADCHAR_CMD;
1626 /* Scan command list and return identity, having set the data pointer
1627 to the start of the actual data characters. Check for SMTP synchronization
1630 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1632 #ifdef SUPPORT_PROXY
1633 /* Only allow QUIT command if Proxy Protocol parsing failed */
1634 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1638 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1639 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1640 || smtp_cmd_buffer[p->len] == 0
1641 || smtp_cmd_buffer[p->len] == ' '
1644 if (smtp_inptr < smtp_inend && /* Outstanding input */
1645 p->cmd < sync_cmd_limit && /* Command should sync */
1646 check_sync && /* Local flag set */
1647 smtp_enforce_sync && /* Global flag set */
1648 sender_host_address != NULL && /* Not local input */
1649 !f.sender_host_notsocket) /* Really is a socket */
1652 /* The variables $smtp_command and $smtp_command_argument point into the
1653 unmodified input buffer. A copy of the latter is taken for actual
1654 processing, so that it can be chopped up into separate parts if necessary,
1655 for example, when processing a MAIL command options such as SIZE that can
1656 follow the sender address. */
1658 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1659 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1660 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1661 smtp_cmd_data = smtp_data_buffer;
1663 /* Count non-mail commands from those hosts that are controlled in this
1664 way. The default is all hosts. We don't waste effort checking the list
1665 until we get a non-mail command, but then cache the result to save checking
1666 again. If there's a DEFER while checking the host, assume it's in the list.
1668 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1669 start of each incoming message by fiddling with the value in the table. */
1671 if (!p->is_mail_cmd)
1673 if (count_nonmail == TRUE_UNSET) count_nonmail =
1674 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1675 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1676 return TOO_MANY_NONMAIL_CMD;
1679 /* If there is data for a command that does not expect it, generate the
1682 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1686 #ifdef SUPPORT_PROXY
1687 /* Only allow QUIT command if Proxy Protocol parsing failed */
1688 if (proxy_session && f.proxy_session_failed)
1689 return PROXY_FAIL_IGNORE_CMD;
1692 /* Enforce synchronization for unknown commands */
1694 if ( smtp_inptr < smtp_inend /* Outstanding input */
1695 && check_sync /* Local flag set */
1696 && smtp_enforce_sync /* Global flag set */
1697 && sender_host_address /* Not local input */
1698 && !f.sender_host_notsocket) /* Really is a socket */
1706 /*************************************************
1707 * Forced closedown of call *
1708 *************************************************/
1710 /* This function is called from log.c when Exim is dying because of a serious
1711 disaster, and also from some other places. If an incoming non-batched SMTP
1712 channel is open, it swallows the rest of the incoming message if in the DATA
1713 phase, sends the reply string, and gives an error to all subsequent commands
1714 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1718 message SMTP reply string to send, excluding the code
1724 smtp_closedown(uschar *message)
1726 if (!smtp_in || smtp_batched_input) return;
1727 receive_swallow_smtp();
1728 smtp_printf("421 %s\r\n", FALSE, message);
1730 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1736 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1741 smtp_printf("250 Reset OK\r\n", FALSE);
1745 smtp_printf("421 %s\r\n", FALSE, message);
1753 /*************************************************
1754 * Set up connection info for logging *
1755 *************************************************/
1757 /* This function is called when logging information about an SMTP connection.
1758 It sets up appropriate source information, depending on the type of connection.
1759 If sender_fullhost is NULL, we are at a very early stage of the connection;
1760 just use the IP address.
1763 Returns: a string describing the connection
1767 smtp_get_connection_info(void)
1769 const uschar * hostname = sender_fullhost
1770 ? sender_fullhost : sender_host_address;
1773 return string_sprintf("SMTP connection from %s", hostname);
1775 if (f.sender_host_unknown || f.sender_host_notsocket)
1776 return string_sprintf("SMTP connection from %s", sender_ident);
1779 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1781 if (LOGGING(incoming_interface) && interface_address)
1782 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1783 interface_address, interface_port);
1785 return string_sprintf("SMTP connection from %s", hostname);
1791 /* Append TLS-related information to a log line
1794 g String under construction: allocated string to extend, or NULL
1796 Returns: Allocated string or NULL
1799 s_tlslog(gstring * g)
1801 if (LOGGING(tls_cipher) && tls_in.cipher)
1803 g = string_append(g, 2, US" X=", tls_in.cipher);
1804 #ifdef EXPERIMENTAL_TLS_RESUME
1805 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1806 g = string_catn(g, US"*", 1);
1809 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1810 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1811 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1812 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1813 if (LOGGING(tls_sni) && tls_in.sni)
1814 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1822 s_connhad_log(gstring * g)
1824 uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1825 ? US" C=..." : US" C=";
1827 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1828 if (smtp_connection_had[i] != SCH_NONE)
1830 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1833 for (int i = 0; i < smtp_ch_index; i++)
1835 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1842 /*************************************************
1843 * Log lack of MAIL if so configured *
1844 *************************************************/
1846 /* This function is called when an SMTP session ends. If the log selector
1847 smtp_no_mail is set, write a log line giving some details of what has happened
1848 in the SMTP session.
1855 smtp_log_no_mail(void)
1860 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1863 if (sender_host_authenticated)
1865 g = string_append(g, 2, US" A=", sender_host_authenticated);
1866 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1873 g = s_connhad_log(g);
1875 if (!(s = string_from_gstring(g))) s = US"";
1877 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1878 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1879 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1883 /* Return list of recent smtp commands */
1888 gstring * list = NULL;
1891 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1892 if (smtp_connection_had[i] != SCH_NONE)
1893 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1895 for (int i = 0; i < smtp_ch_index; i++)
1896 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1898 s = string_from_gstring(list);
1899 return s ? s : US"";
1905 /*************************************************
1906 * Check HELO line and set sender_helo_name *
1907 *************************************************/
1909 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1910 the domain name of the sending host, or an ip literal in square brackets. The
1911 argument is placed in sender_helo_name, which is in malloc store, because it
1912 must persist over multiple incoming messages. If helo_accept_junk is set, this
1913 host is permitted to send any old junk (needed for some broken hosts).
1914 Otherwise, helo_allow_chars can be used for rogue characters in general
1915 (typically people want to let in underscores).
1918 s the data portion of the line (already past any white space)
1920 Returns: TRUE or FALSE
1924 check_helo(uschar *s)
1927 uschar *end = s + Ustrlen(s);
1928 BOOL yield = fl.helo_accept_junk;
1930 /* Discard any previous helo name */
1932 sender_helo_name = NULL;
1934 /* Skip tests if junk is permitted. */
1938 /* Allow the new standard form for IPv6 address literals, namely,
1939 [IPv6:....], and because someone is bound to use it, allow an equivalent
1940 IPv4 form. Allow plain addresses as well. */
1947 if (strncmpic(s, US"[IPv6:", 6) == 0)
1948 yield = (string_is_ip_address(s+6, NULL) == 6);
1949 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1950 yield = (string_is_ip_address(s+6, NULL) == 4);
1952 yield = (string_is_ip_address(s+1, NULL) != 0);
1957 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1958 that have been configured (usually underscore - sigh). */
1961 for (yield = TRUE; *s; s++)
1962 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1963 Ustrchr(helo_allow_chars, *s) == NULL)
1969 /* Save argument if OK */
1971 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1979 /*************************************************
1980 * Extract SMTP command option *
1981 *************************************************/
1983 /* This function picks the next option setting off the end of smtp_cmd_data. It
1984 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1985 things that can appear there.
1988 name point this at the name
1989 value point this at the data string
1991 Returns: TRUE if found an option
1995 extract_option(uschar **name, uschar **value)
1998 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1999 while (isspace(*v)) v--;
2001 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2003 /* Take care to not stop at a space embedded in a quoted local-part */
2005 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
2012 while(isalpha(n[-1])) n--;
2013 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2014 if (!isspace(n[-1])) return FALSE;
2020 if (v == smtp_cmd_data) return FALSE;
2032 /*************************************************
2033 * Reset for new message *
2034 *************************************************/
2036 /* This function is called whenever the SMTP session is reset from
2037 within either of the setup functions; also from the daemon loop.
2039 Argument: the stacking pool storage reset point
2044 smtp_reset(void *reset_point)
2046 recipients_list = NULL;
2047 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2048 raw_recipients_count = recipients_count = recipients_list_max = 0;
2049 message_linecount = 0;
2051 acl_added_headers = NULL;
2052 acl_removed_headers = NULL;
2053 f.queue_only_policy = FALSE;
2054 rcpt_smtp_response = NULL;
2055 fl.rcpt_smtp_response_same = TRUE;
2056 fl.rcpt_in_progress = FALSE;
2057 f.deliver_freeze = FALSE; /* Can be set by ACL */
2058 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2059 fake_response = OK; /* Can be set by ACL */
2060 #ifdef WITH_CONTENT_SCAN
2061 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2063 f.submission_mode = FALSE; /* Can be set by ACL */
2064 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2065 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2066 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2067 sending_ip_address = NULL;
2068 return_path = sender_address = NULL;
2069 deliver_localpart_data = deliver_domain_data =
2070 recipient_data = sender_data = NULL; /* Can be set by ACL */
2071 deliver_localpart_parent = deliver_localpart_orig = NULL;
2072 deliver_domain_parent = deliver_domain_orig = NULL;
2073 callout_address = NULL;
2074 submission_name = NULL; /* Can be set by ACL */
2075 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2076 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2077 sender_verified_list = NULL; /* No senders verified */
2078 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2079 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2081 authenticated_sender = NULL;
2082 #ifdef EXPERIMENTAL_BRIGHTMAIL
2084 bmi_verdicts = NULL;
2086 dnslist_domain = dnslist_matched = NULL;
2088 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2089 spf_result_guessed = FALSE;
2091 #ifndef DISABLE_DKIM
2092 dkim_cur_signer = dkim_signers =
2093 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2094 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2095 f.dkim_disable_verify = FALSE;
2096 dkim_collect_input = 0;
2097 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2098 dkim_key_length = 0;
2100 #ifdef SUPPORT_DMARC
2101 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2102 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2103 dmarc_used_domain = NULL;
2105 #ifdef EXPERIMENTAL_ARC
2106 arc_state = arc_state_reason = NULL;
2107 arc_received_instance = 0;
2111 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2112 #ifndef DISABLE_PRDR
2113 prdr_requested = FALSE;
2116 message_smtputf8 = FALSE;
2118 body_linecount = body_zerocount = 0;
2120 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2121 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2122 /* Note that ratelimiters_conn persists across resets. */
2124 /* Reset message ACL variables */
2128 /* The message body variables use malloc store. They may be set if this is
2129 not the first message in an SMTP session and the previous message caused them
2130 to be referenced in an ACL. */
2134 store_free(message_body);
2135 message_body = NULL;
2138 if (message_body_end)
2140 store_free(message_body_end);
2141 message_body_end = NULL;
2144 /* Warning log messages are also saved in malloc store. They are saved to avoid
2145 repetition in the same message, but it seems right to repeat them for different
2148 while (acl_warn_logged)
2150 string_item *this = acl_warn_logged;
2151 acl_warn_logged = acl_warn_logged->next;
2154 store_reset(reset_point);
2155 return store_mark();
2162 /*************************************************
2163 * Initialize for incoming batched SMTP message *
2164 *************************************************/
2166 /* This function is called from smtp_setup_msg() in the case when
2167 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2168 of messages in one file with SMTP commands between them. All errors must be
2169 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2170 relevant. After an error on a sender, or an invalid recipient, the remainder
2171 of the message is skipped. The value of received_protocol is already set.
2174 Returns: > 0 message successfully started (reached DATA)
2175 = 0 QUIT read or end of file reached
2176 < 0 should not occur
2180 smtp_setup_batch_msg(void)
2183 rmark reset_point = store_mark();
2185 /* Save the line count at the start of each transaction - single commands
2186 like HELO and RSET count as whole transactions. */
2188 bsmtp_transaction_linecount = receive_linecount;
2190 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2192 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2193 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2195 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2196 value. The values are 2 larger than the required yield of the function. */
2201 uschar *recipient = NULL;
2202 int start, end, sender_domain, recipient_domain;
2204 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2206 /* The HELO/EHLO commands set sender_address_helo if they have
2207 valid data; otherwise they are ignored, except that they do
2208 a reset of the state. */
2213 check_helo(smtp_cmd_data);
2217 cancel_cutthrough_connection(TRUE, US"RSET received");
2218 reset_point = smtp_reset(reset_point);
2219 bsmtp_transaction_linecount = receive_linecount;
2223 /* The MAIL FROM command requires an address as an operand. All we
2224 do here is to parse it for syntactic correctness. The form "<>" is
2225 a special case which converts into an empty string. The start/end
2226 pointers in the original are not used further for this address, as
2227 it is the canonical extracted address which is all that is kept. */
2230 smtp_mailcmd_count++; /* Count for no-mail log */
2231 if (sender_address != NULL)
2232 /* The function moan_smtp_batch() does not return. */
2233 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2235 if (smtp_cmd_data[0] == 0)
2236 /* The function moan_smtp_batch() does not return. */
2237 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2239 /* Reset to start of message */
2241 cancel_cutthrough_connection(TRUE, US"MAIL received");
2242 reset_point = smtp_reset(reset_point);
2244 /* Apply SMTP rewrite */
2246 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2247 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2248 US"", global_rewrite_rules) : smtp_cmd_data;
2250 /* Extract the address; the TRUE flag allows <> as valid */
2253 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2257 /* The function moan_smtp_batch() does not return. */
2258 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2260 sender_address = string_copy(raw_sender);
2262 /* Qualify unqualified sender addresses if permitted to do so. */
2265 && sender_address[0] != 0 && sender_address[0] != '@')
2266 if (f.allow_unqualified_sender)
2268 sender_address = rewrite_address_qualify(sender_address, FALSE);
2269 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2270 "and rewritten\n", raw_sender);
2272 /* The function moan_smtp_batch() does not return. */
2274 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2279 /* The RCPT TO command requires an address as an operand. All we do
2280 here is to parse it for syntactic correctness. There may be any number
2281 of RCPT TO commands, specifying multiple senders. We build them all into
2282 a data structure that is in argc/argv format. The start/end values
2283 given by parse_extract_address are not used, as we keep only the
2284 extracted address. */
2287 if (!sender_address)
2288 /* The function moan_smtp_batch() does not return. */
2289 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2291 if (smtp_cmd_data[0] == 0)
2292 /* The function moan_smtp_batch() does not return. */
2293 moan_smtp_batch(smtp_cmd_buffer,
2294 "501 RCPT TO must have an address operand");
2296 /* Check maximum number allowed */
2298 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2299 /* The function moan_smtp_batch() does not return. */
2300 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2301 recipients_max_reject? "552": "452");
2303 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2304 recipient address */
2306 recipient = rewrite_existflags & rewrite_smtp
2307 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2308 global_rewrite_rules)
2311 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2312 &recipient_domain, FALSE);
2315 /* The function moan_smtp_batch() does not return. */
2316 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2318 /* If the recipient address is unqualified, qualify it if permitted. Then
2319 add it to the list of recipients. */
2321 if (!recipient_domain)
2322 if (f.allow_unqualified_recipient)
2324 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2326 recipient = rewrite_address_qualify(recipient, TRUE);
2328 /* The function moan_smtp_batch() does not return. */
2330 moan_smtp_batch(smtp_cmd_buffer,
2331 "501 recipient address must contain a domain");
2333 receive_add_recipient(recipient, -1);
2337 /* The DATA command is legal only if it follows successful MAIL FROM
2338 and RCPT TO commands. This function is complete when a valid DATA
2339 command is encountered. */
2342 if (!sender_address || recipients_count <= 0)
2343 /* The function moan_smtp_batch() does not return. */
2344 if (!sender_address)
2345 moan_smtp_batch(smtp_cmd_buffer,
2346 "503 MAIL FROM:<sender> command must precede DATA");
2348 moan_smtp_batch(smtp_cmd_buffer,
2349 "503 RCPT TO:<recipient> must precede DATA");
2352 done = 3; /* DATA successfully achieved */
2353 message_ended = END_NOTENDED; /* Indicate in middle of message */
2358 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2365 bsmtp_transaction_linecount = receive_linecount;
2376 /* The function moan_smtp_batch() does not return. */
2377 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2382 /* The function moan_smtp_batch() does not return. */
2383 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2388 /* The function moan_smtp_batch() does not return. */
2389 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2394 return done - 2; /* Convert yield values */
2402 smtp_log_tls_fail(uschar * errstr)
2404 uschar * conn_info = smtp_get_connection_info();
2406 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2407 /* I'd like to get separated H= here, but too hard for now */
2409 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2423 socklen_t len = sizeof(is_fastopen);
2425 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2426 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2428 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2433 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2434 f.tcp_in_fastopen = TRUE;
2437 else DEBUG(D_receive)
2438 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2440 # elif defined(TCP_INFO)
2441 struct tcp_info tinfo;
2442 socklen_t len = sizeof(tinfo);
2444 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2445 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2446 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2449 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2450 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2454 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2457 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2458 f.tcp_in_fastopen = TRUE;
2460 else DEBUG(D_receive)
2461 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2467 /*************************************************
2468 * Start an SMTP session *
2469 *************************************************/
2471 /* This function is called at the start of an SMTP session. Thereafter,
2472 smtp_setup_msg() is called to initiate each separate message. This
2473 function does host-specific testing, and outputs the banner line.
2476 Returns: FALSE if the session can not continue; something has
2477 gone wrong, or the connection to the host is blocked
2481 smtp_start_session(void)
2484 uschar *user_msg, *log_msg;
2489 gettimeofday(&smtp_connection_start, NULL);
2490 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2491 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2494 /* Default values for certain variables */
2496 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2497 smtp_mailcmd_count = 0;
2498 count_nonmail = TRUE_UNSET;
2499 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2500 smtp_delay_mail = smtp_rlm_base;
2501 fl.auth_advertised = FALSE;
2502 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2503 f.pipelining_enable = TRUE;
2504 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2505 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2507 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2508 authentication settings from -oMaa to remain in force. */
2510 if (!host_checking && !f.sender_host_notsocket)
2511 sender_host_auth_pubname = sender_host_authenticated = NULL;
2512 authenticated_by = NULL;
2515 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2516 tls_in.ourcert = tls_in.peercert = NULL;
2518 tls_in.ocsp = OCSP_NOT_REQ;
2519 fl.tls_advertised = FALSE;
2521 fl.dsn_advertised = FALSE;
2523 fl.smtputf8_advertised = FALSE;
2526 /* Reset ACL connection variables */
2530 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2532 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2534 smtp_cmd_buffer[0] = 0;
2535 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2537 /* For batched input, the protocol setting can be overridden from the
2538 command line by a trusted caller. */
2540 if (smtp_batched_input)
2542 if (!received_protocol) received_protocol = US"local-bsmtp";
2545 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2546 reset later if any of EHLO/AUTH/STARTTLS are received. */
2550 (sender_host_address ? protocols : protocols_local) [pnormal];
2552 /* Set up the buffer for inputting using direct read() calls, and arrange to
2553 call the local functions instead of the standard C ones. Place a NUL at the
2554 end of the buffer to safety-stop C-string reads from it. */
2556 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2557 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2558 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2560 receive_getc = smtp_getc;
2561 receive_getbuf = smtp_getbuf;
2562 receive_get_cache = smtp_get_cache;
2563 receive_ungetc = smtp_ungetc;
2564 receive_feof = smtp_feof;
2565 receive_ferror = smtp_ferror;
2566 receive_smtp_buffered = smtp_buffered;
2567 smtp_inptr = smtp_inend = smtp_inbuffer;
2568 smtp_had_eof = smtp_had_error = 0;
2570 /* Set up the message size limit; this may be host-specific */
2572 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2573 if (expand_string_message)
2575 if (thismessage_size_limit == -1)
2576 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2577 "%s", expand_string_message);
2579 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2580 "%s", expand_string_message);
2581 smtp_closedown(US"Temporary local problem - please try later");
2585 /* When a message is input locally via the -bs or -bS options, sender_host_
2586 unknown is set unless -oMa was used to force an IP address, in which case it
2587 is checked like a real remote connection. When -bs is used from inetd, this
2588 flag is not set, causing the sending host to be checked. The code that deals
2589 with IP source routing (if configured) is never required for -bs or -bS and
2590 the flag sender_host_notsocket is used to suppress it.
2592 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2593 reserve for certain hosts and/or networks. */
2595 if (!f.sender_host_unknown)
2598 BOOL reserved_host = FALSE;
2600 /* Look up IP options (source routing info) on the socket if this is not an
2601 -oMa "host", and if any are found, log them and drop the connection.
2603 Linux (and others now, see below) is different to everyone else, so there
2604 has to be some conditional compilation here. Versions of Linux before 2.1.15
2605 used a structure whose name was "options". Somebody finally realized that
2606 this name was silly, and it got changed to "ip_options". I use the
2607 newer name here, but there is a fudge in the script that sets up os.h
2608 to define a macro in older Linux systems.
2610 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2611 glibc 2, which has chosen ip_opts for the structure name. This is now
2612 really a glibc thing rather than a Linux thing, so the condition name
2613 has been changed to reflect this. It is relevant also to GNU/Hurd.
2615 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2616 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2617 a special macro defined in the os.h file.
2619 Some DGUX versions on older hardware appear not to support IP options at
2620 all, so there is now a general macro which can be set to cut out this
2623 How to do this properly in IPv6 is not yet known. */
2625 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2627 #ifdef GLIBC_IP_OPTIONS
2628 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2633 #elif defined DARWIN_IP_OPTIONS
2639 if (!host_checking && !f.sender_host_notsocket)
2642 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2643 struct ip_options *ipopt = store_get(optlen, FALSE);
2645 struct ip_opts ipoptblock;
2646 struct ip_opts *ipopt = &ipoptblock;
2647 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2649 struct ipoption ipoptblock;
2650 struct ipoption *ipopt = &ipoptblock;
2651 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2654 /* Occasional genuine failures of getsockopt() have been seen - for
2655 example, "reset by peer". Therefore, just log and give up on this
2656 call, unless the error is ENOPROTOOPT. This error is given by systems
2657 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2658 of writing. So for that error, carry on - we just can't do an IP options
2661 DEBUG(D_receive) debug_printf("checking for IP options\n");
2663 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2666 if (errno != ENOPROTOOPT)
2668 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2669 host_and_ident(FALSE), strerror(errno));
2670 smtp_printf("451 SMTP service not available\r\n", FALSE);
2675 /* Deal with any IP options that are set. On the systems I have looked at,
2676 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2677 more logging data than will fit in big_buffer. Nevertheless, after somebody
2678 questioned this code, I've added in some paranoid checking. */
2680 else if (optlen > 0)
2682 uschar *p = big_buffer;
2683 uschar *pend = big_buffer + big_buffer_size;
2686 struct in_addr addr;
2689 uschar *optstart = US (ipopt->__data);
2691 uschar *optstart = US (ipopt->ip_opts);
2693 uschar *optstart = US (ipopt->ipopt_list);
2696 DEBUG(D_receive) debug_printf("IP options exist\n");
2698 Ustrcpy(p, "IP options on incoming call:");
2701 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2714 if (!string_format(p, pend-p, " %s [@%s",
2715 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2717 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2719 inet_ntoa(ipopt->ip_dst)))
2721 inet_ntoa(ipopt->ipopt_dst)))
2729 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2731 while (optcount-- > 0)
2733 memcpy(&addr, adptr, sizeof(addr));
2734 if (!string_format(p, pend - p - 1, "%s%s",
2735 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2741 adptr += sizeof(struct in_addr);
2749 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2752 for (int i = 0; i < opt[1]; i++)
2753 p += sprintf(CS p, "%2.2x ", opt[i]);
2761 log_write(0, LOG_MAIN, "%s", big_buffer);
2763 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2765 log_write(0, LOG_MAIN|LOG_REJECT,
2766 "connection from %s refused (IP options)", host_and_ident(FALSE));
2768 smtp_printf("554 SMTP service not available\r\n", FALSE);
2772 /* Length of options = 0 => there are no options */
2774 else DEBUG(D_receive) debug_printf("no IP options found\n");
2776 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2778 /* Set keep-alive in socket options. The option is on by default. This
2779 setting is an attempt to get rid of some hanging connections that stick in
2780 read() when the remote end (usually a dialup) goes away. */
2782 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2783 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2785 /* If the current host matches host_lookup, set the name by doing a
2786 reverse lookup. On failure, sender_host_name will be NULL and
2787 host_lookup_failed will be TRUE. This may or may not be serious - optional
2790 if (verify_check_host(&host_lookup) == OK)
2792 (void)host_name_lookup();
2793 host_build_sender_fullhost();
2796 /* Delay this until we have the full name, if it is looked up. */
2798 set_process_info("handling incoming connection from %s",
2799 host_and_ident(FALSE));
2801 /* Expand smtp_receive_timeout, if needed */
2803 if (smtp_receive_timeout_s)
2806 if ( !(exp = expand_string(smtp_receive_timeout_s))
2808 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2810 log_write(0, LOG_MAIN|LOG_PANIC,
2811 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2814 /* Test for explicit connection rejection */
2816 if (verify_check_host(&host_reject_connection) == OK)
2818 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2819 "from %s (host_reject_connection)", host_and_ident(FALSE));
2820 smtp_printf("554 SMTP service not available\r\n", FALSE);
2824 /* Test with TCP Wrappers if so configured. There is a problem in that
2825 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2826 such as disks dying. In these cases, it is desirable to reject with a 4xx
2827 error instead of a 5xx error. There isn't a "right" way to detect such
2828 problems. The following kludge is used: errno is zeroed before calling
2829 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2830 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2833 #ifdef USE_TCP_WRAPPERS
2835 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2836 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2837 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2838 expand_string_message);
2840 if (!hosts_ctl(tcp_wrappers_name,
2841 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2842 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2843 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2845 if (errno == 0 || errno == ENOENT)
2847 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2848 log_write(L_connection_reject,
2849 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2850 "(tcp wrappers)", host_and_ident(FALSE));
2851 smtp_printf("554 SMTP service not available\r\n", FALSE);
2855 int save_errno = errno;
2856 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2857 "errno value %d\n", save_errno);
2858 log_write(L_connection_reject,
2859 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2860 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2861 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2867 /* Check for reserved slots. The value of smtp_accept_count has already been
2868 incremented to include this process. */
2870 if (smtp_accept_max > 0 &&
2871 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2873 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2875 log_write(L_connection_reject,
2876 LOG_MAIN, "temporarily refused connection from %s: not in "
2877 "reserve list: connected=%d max=%d reserve=%d%s",
2878 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2879 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2880 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2881 "please try again later\r\n", FALSE, smtp_active_hostname);
2884 reserved_host = TRUE;
2887 /* If a load level above which only messages from reserved hosts are
2888 accepted is set, check the load. For incoming calls via the daemon, the
2889 check is done in the superior process if there are no reserved hosts, to
2890 save a fork. In all cases, the load average will already be available
2891 in a global variable at this point. */
2893 if (smtp_load_reserve >= 0 &&
2894 load_average > smtp_load_reserve &&
2896 verify_check_host(&smtp_reserve_hosts) != OK)
2898 log_write(L_connection_reject,
2899 LOG_MAIN, "temporarily refused connection from %s: not in "
2900 "reserve list and load average = %.2f", host_and_ident(FALSE),
2901 (double)load_average/1000.0);
2902 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2903 smtp_active_hostname);
2907 /* Determine whether unqualified senders or recipients are permitted
2908 for this host. Unfortunately, we have to do this every time, in order to
2909 set the flags so that they can be inspected when considering qualifying
2910 addresses in the headers. For a site that permits no qualification, this
2911 won't take long, however. */
2913 f.allow_unqualified_sender =
2914 verify_check_host(&sender_unqualified_hosts) == OK;
2916 f.allow_unqualified_recipient =
2917 verify_check_host(&recipient_unqualified_hosts) == OK;
2919 /* Determine whether HELO/EHLO is required for this host. The requirement
2920 can be hard or soft. */
2922 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2923 if (!fl.helo_required)
2924 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2926 /* Determine whether this hosts is permitted to send syntactic junk
2927 after a HELO or EHLO command. */
2929 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2932 /* For batch SMTP input we are now done. */
2934 if (smtp_batched_input) return TRUE;
2936 /* If valid Proxy Protocol source is connecting, set up session.
2937 * Failure will not allow any SMTP function other than QUIT. */
2939 #ifdef SUPPORT_PROXY
2940 proxy_session = FALSE;
2941 f.proxy_session_failed = FALSE;
2942 if (check_proxy_protocol_host())
2943 setup_proxy_protocol_host();
2946 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2947 smtps port for use with older style SSL MTAs. */
2950 if (tls_in.on_connect)
2952 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2953 return smtp_log_tls_fail(user_msg);
2954 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2958 /* Run the connect ACL if it exists */
2961 if (acl_smtp_connect)
2964 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2967 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2972 /* Output the initial message for a two-way SMTP connection. It may contain
2973 newlines, which then cause a multi-line response to be given. */
2975 code = US"220"; /* Default status code */
2976 esc = US""; /* Default extended status code */
2977 esclen = 0; /* Length of esc */
2981 if (!(s = expand_string(smtp_banner)))
2982 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2983 "failed: %s", smtp_banner, expand_string_message);
2989 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2993 esclen = codelen - 4;
2997 /* Remove any terminating newlines; might as well remove trailing space too */
3000 while (p > s && isspace(p[-1])) p--;
3003 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3004 is all contained in a single IP packet. The original code wrote out the
3005 greeting using several calls to fprint/fputc, and on busy servers this could
3006 cause it to be split over more than one packet - which caused CC:Mail to fall
3007 over when it got the second part of the greeting after sending its first
3008 command. Sigh. To try to avoid this, build the complete greeting message
3009 first, and output it in one fell swoop. This gives a better chance of it
3010 ending up as a single packet. */
3012 ss = string_get(256);
3015 do /* At least once, in case we have an empty string */
3018 uschar *linebreak = Ustrchr(p, '\n');
3019 ss = string_catn(ss, code, 3);
3023 ss = string_catn(ss, US" ", 1);
3027 len = linebreak - p;
3028 ss = string_catn(ss, US"-", 1);
3030 ss = string_catn(ss, esc, esclen);
3031 ss = string_catn(ss, p, len);
3032 ss = string_catn(ss, US"\r\n", 2);
3038 /* Before we write the banner, check that there is no input pending, unless
3039 this synchronisation check is disabled. */
3041 #ifndef DISABLE_PIPE_CONNECT
3042 fl.pipe_connect_acceptable =
3043 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3046 if (fl.pipe_connect_acceptable)
3047 f.smtp_in_early_pipe_used = TRUE;
3053 unsigned n = smtp_inend - smtp_inptr;
3054 if (n > 128) n = 128;
3056 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3057 "synchronization error (input sent without waiting for greeting): "
3058 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3059 string_printing(string_copyn(smtp_inptr, n)));
3060 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3064 /* Now output the banner */
3065 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3068 #ifndef DISABLE_PIPE_CONNECT
3069 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3073 string_from_gstring(ss));
3075 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3076 handshake arrived. If so we must have managed a TFO. */
3079 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3089 /*************************************************
3090 * Handle SMTP syntax and protocol errors *
3091 *************************************************/
3093 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3094 to do so. Then transmit the error response. The return value depends on the
3095 number of syntax and protocol errors in this SMTP session.
3098 type error type, given as a log flag bit
3099 code response code; <= 0 means don't send a response
3100 data data to reflect in the response (can be NULL)
3101 errmess the error message
3103 Returns: -1 limit of syntax/protocol errors NOT exceeded
3104 +1 limit of syntax/protocol errors IS exceeded
3106 These values fit in with the values of the "done" variable in the main
3107 processing loop in smtp_setup_msg(). */
3110 synprot_error(int type, int code, uschar *data, uschar *errmess)
3114 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3115 type == L_smtp_syntax_error ? "syntax" : "protocol",
3116 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3118 if (++synprot_error_count > smtp_max_synprot_errors)
3121 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3122 "syntax or protocol errors (last command was \"%s\", %s)",
3123 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3124 string_from_gstring(s_connhad_log(NULL))
3130 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3131 data ? data : US"", data ? US": " : US"", errmess);
3133 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3142 /*************************************************
3143 * Send SMTP response, possibly multiline *
3144 *************************************************/
3146 /* There are, it seems, broken clients out there that cannot handle multiline
3147 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3148 output nothing for non-final calls, and only the first line for anything else.
3151 code SMTP code, may involve extended status codes
3152 codelen length of smtp code; if > 4 there's an ESC
3153 final FALSE if the last line isn't the final line
3154 msg message text, possibly containing newlines
3160 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3165 if (!final && f.no_multiline_responses) return;
3170 esclen = codelen - 4;
3173 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3174 have had the same. Note: this code is also present in smtp_printf(). It would
3175 be tidier to have it only in one place, but when it was added, it was easier to
3176 do it that way, so as not to have to mess with the code for the RCPT command,
3177 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3179 if (fl.rcpt_in_progress)
3181 if (rcpt_smtp_response == NULL)
3182 rcpt_smtp_response = string_copy(msg);
3183 else if (fl.rcpt_smtp_response_same &&
3184 Ustrcmp(rcpt_smtp_response, msg) != 0)
3185 fl.rcpt_smtp_response_same = FALSE;
3186 fl.rcpt_in_progress = FALSE;
3189 /* Now output the message, splitting it up into multiple lines if necessary.
3190 We only handle pipelining these responses as far as nonfinal/final groups,
3191 not the whole MAIL/RCPT/DATA response set. */
3195 uschar *nl = Ustrchr(msg, '\n');
3198 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3201 else if (nl[1] == 0 || f.no_multiline_responses)
3203 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3204 (int)(nl - msg), msg);
3209 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3211 Uskip_whitespace(&msg);
3219 /*************************************************
3220 * Parse user SMTP message *
3221 *************************************************/
3223 /* This function allows for user messages overriding the response code details
3224 by providing a suitable response code string at the start of the message
3225 user_msg. Check the message for starting with a response code and optionally an
3226 extended status code. If found, check that the first digit is valid, and if so,
3227 change the code pointer and length to use the replacement. An invalid code
3228 causes a panic log; in this case, if the log messages is the same as the user
3229 message, we must also adjust the value of the log message to show the code that
3230 is actually going to be used (the original one).
3232 This function is global because it is called from receive.c as well as within
3235 Note that the code length returned includes the terminating whitespace
3236 character, which is always included in the regex match.
3239 code SMTP code, may involve extended status codes
3240 codelen length of smtp code; if > 4 there's an ESC
3242 log_msg optional log message, to be adjusted with the new SMTP code
3243 check_valid if true, verify the response code
3249 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3255 if (!msg || !*msg) return;
3257 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3258 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3260 if (check_valid && (*msg)[0] != (*code)[0])
3262 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3263 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3264 if (log_msg != NULL && *log_msg == *msg)
3265 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3270 *codelen = ovector[1]; /* Includes final space */
3272 *msg += ovector[1]; /* Chop the code off the message */
3279 /*************************************************
3280 * Handle an ACL failure *
3281 *************************************************/
3283 /* This function is called when acl_check() fails. As well as calls from within
3284 this module, it is called from receive.c for an ACL after DATA. It sorts out
3285 logging the incident, and sends the error response. A message containing
3286 newlines is turned into a multiline SMTP response, but for logging, only the
3289 There's a table of default permanent failure response codes to use in
3290 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3291 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3292 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3293 state, because there are broken clients that try VRFY before RCPT. A 5xx
3294 response should be given only when the address is positively known to be
3295 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3296 no explicit code, but if there is one we let it know best.
3297 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3299 From Exim 4.63, it is possible to override the response code details by
3300 providing a suitable response code string at the start of the message provided
3301 in user_msg. The code's first digit is checked for validity.
3304 where where the ACL was called from
3306 user_msg a message that can be included in an SMTP response
3307 log_msg a message for logging
3309 Returns: 0 in most cases
3310 2 if the failure code was FAIL_DROP, in which case the
3311 SMTP connection should be dropped (this value fits with the
3312 "done" variable in smtp_setup_msg() below)
3316 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3318 BOOL drop = rc == FAIL_DROP;
3322 uschar *sender_info = US"";
3324 #ifdef WITH_CONTENT_SCAN
3325 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3327 where == ACL_WHERE_PREDATA ? US"DATA" :
3328 where == ACL_WHERE_DATA ? US"after DATA" :
3329 #ifndef DISABLE_PRDR
3330 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3333 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3334 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3336 if (drop) rc = FAIL;
3338 /* Set the default SMTP code, and allow a user message to change it. */
3340 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3341 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3342 where != ACL_WHERE_VRFY);
3344 /* We used to have sender_address here; however, there was a bug that was not
3345 updating sender_address after a rewrite during a verify. When this bug was
3346 fixed, sender_address at this point became the rewritten address. I'm not sure
3347 this is what should be logged, so I've changed to logging the unrewritten
3348 address to retain backward compatibility. */
3350 #ifndef WITH_CONTENT_SCAN
3351 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3353 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3356 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3357 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3358 sender_host_authenticated ? US" A=" : US"",
3359 sender_host_authenticated ? sender_host_authenticated : US"",
3360 sender_host_authenticated && authenticated_id ? US":" : US"",
3361 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3365 /* If there's been a sender verification failure with a specific message, and
3366 we have not sent a response about it yet, do so now, as a preliminary line for
3367 failures, but not defers. However, always log it for defer, and log it for fail
3368 unless the sender_verify_fail log selector has been turned off. */
3370 if (sender_verified_failed &&
3371 !testflag(sender_verified_failed, af_sverify_told))
3373 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3374 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3376 setflag(sender_verified_failed, af_sverify_told);
3378 if (rc != FAIL || LOGGING(sender_verify_fail))
3379 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3380 host_and_ident(TRUE),
3381 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3382 sender_verified_failed->address,
3383 (sender_verified_failed->message == NULL)? US"" :
3384 string_sprintf(": %s", sender_verified_failed->message));
3386 if (rc == FAIL && sender_verified_failed->user_message)
3387 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3388 testflag(sender_verified_failed, af_verify_pmfail)?
3389 "Postmaster verification failed while checking <%s>\n%s\n"
3390 "Several RFCs state that you are required to have a postmaster\n"
3391 "mailbox for each mail domain. This host does not accept mail\n"
3392 "from domains whose servers reject the postmaster address."
3394 testflag(sender_verified_failed, af_verify_nsfail)?
3395 "Callback setup failed while verifying <%s>\n%s\n"
3396 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3397 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3398 "RFC requirements, and stops you from receiving standard bounce\n"
3399 "messages. This host does not accept mail from domains whose servers\n"
3402 "Verification failed for <%s>\n%s",
3403 sender_verified_failed->address,
3404 sender_verified_failed->user_message));
3406 fl.rcpt_in_progress = save_rcpt_in_progress;
3409 /* Sort out text for logging */
3411 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3412 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3414 /* Send permanent failure response to the command, but the code used isn't
3415 always a 5xx one - see comments at the start of this function. If the original
3416 rc was FAIL_DROP we drop the connection and yield 2. */
3419 smtp_respond(smtp_code, codelen, TRUE,
3420 user_msg ? user_msg : US"Administrative prohibition");
3422 /* Send temporary failure response to the command. Don't give any details,
3423 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3424 verb, and for a header verify when smtp_return_error_details is set.
3426 This conditional logic is all somewhat of a mess because of the odd
3427 interactions between temp_details and return_error_details. One day it should
3428 be re-implemented in a tidier fashion. */
3431 if (f.acl_temp_details && user_msg)
3433 if ( smtp_return_error_details
3434 && sender_verified_failed
3435 && sender_verified_failed->message
3437 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3439 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3442 smtp_respond(smtp_code, codelen, TRUE,
3443 US"Temporary local problem - please try later");
3445 /* Log the incident to the logs that are specified by log_reject_target
3446 (default main, reject). This can be empty to suppress logging of rejections. If
3447 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3448 is closing if required and return 2. */
3450 if (log_reject_target != 0)
3453 gstring * g = s_tlslog(NULL);
3454 uschar * tls = string_from_gstring(g);
3455 if (!tls) tls = US"";
3457 uschar * tls = US"";
3459 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3460 log_reject_target, "%s%s%s %s%srejected %s%s",
3461 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3462 host_and_ident(TRUE),
3465 rc == FAIL ? US"" : US"temporarily ",
3469 if (!drop) return 0;
3471 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3472 smtp_get_connection_info());
3474 /* Run the not-quit ACL, but without any custom messages. This should not be a
3475 problem, because we get here only if some other ACL has issued "drop", and
3476 in that case, *its* custom messages will have been used above. */
3478 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3485 /*************************************************
3486 * Handle SMTP exit when QUIT is not given *
3487 *************************************************/
3489 /* This function provides a logging/statistics hook for when an SMTP connection
3490 is dropped on the floor or the other end goes away. It's a global function
3491 because it's called from receive.c as well as this module. As well as running
3492 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3493 response, either with a custom message from the ACL, or using a default. There
3494 is one case, however, when no message is output - after "drop". In that case,
3495 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3496 passed to this function.
3498 In case things go wrong while processing this function, causing an error that
3499 may re-enter this function, there is a recursion check.
3502 reason What $smtp_notquit_reason will be set to in the ACL;
3503 if NULL, the ACL is not run
3504 code The error code to return as part of the response
3505 defaultrespond The default message if there's no user_msg
3511 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3514 uschar *user_msg = NULL;
3515 uschar *log_msg = NULL;
3517 /* Check for recursive call */
3519 if (fl.smtp_exit_function_called)
3521 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3525 fl.smtp_exit_function_called = TRUE;
3527 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3529 if (acl_smtp_notquit && reason)
3531 smtp_notquit_reason = reason;
3532 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3533 &log_msg)) == ERROR)
3534 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3538 /* If the connection was dropped, we certainly are no longer talking TLS */
3539 tls_in.active.sock = -1;
3541 /* Write an SMTP response if we are expected to give one. As the default
3542 responses are all internal, they should be reasonable size. */
3544 if (code && defaultrespond)
3547 smtp_respond(code, 3, TRUE, user_msg);
3553 va_start(ap, defaultrespond);
3554 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3556 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3565 /*************************************************
3566 * Verify HELO argument *
3567 *************************************************/
3569 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3570 matched. It is also called from ACL processing if verify = helo is used and
3571 verification was not previously tried (i.e. helo_try_verify_hosts was not
3572 matched). The result of its processing is to set helo_verified and
3573 helo_verify_failed. These variables should both be FALSE for this function to
3576 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3577 for IPv6 ::ffff: literals.
3580 Returns: TRUE if testing was completed;
3581 FALSE on a temporary failure
3585 smtp_verify_helo(void)
3589 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3592 if (sender_helo_name == NULL)
3594 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3597 /* Deal with the case of -bs without an IP address */
3599 else if (sender_host_address == NULL)
3601 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3602 f.helo_verified = TRUE;
3605 /* Deal with the more common case when there is a sending IP address */
3607 else if (sender_helo_name[0] == '[')
3609 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3610 Ustrlen(sender_host_address)) == 0;
3613 if (!f.helo_verified)
3615 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3616 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3617 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3622 { if (f.helo_verified) debug_printf("matched host address\n"); }
3625 /* Do a reverse lookup if one hasn't already given a positive or negative
3626 response. If that fails, or the name doesn't match, try checking with a forward
3631 if (sender_host_name == NULL && !host_lookup_failed)
3632 yield = host_name_lookup() != DEFER;
3634 /* If a host name is known, check it and all its aliases. */
3636 if (sender_host_name)
3637 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3639 sender_helo_dnssec = sender_host_dnssec;
3640 HDEBUG(D_receive) debug_printf("matched host name\n");
3644 uschar **aliases = sender_host_aliases;
3646 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3648 sender_helo_dnssec = sender_host_dnssec;
3652 HDEBUG(D_receive) if (f.helo_verified)
3653 debug_printf("matched alias %s\n", *(--aliases));
3656 /* Final attempt: try a forward lookup of the helo name */
3658 if (!f.helo_verified)
3662 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3664 {.request = US"*", .require = US""};
3666 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3668 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3669 NULL, NULL, NULL, &d, NULL, NULL);
3670 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3671 for (host_item * hh = &h; hh; hh = hh->next)
3672 if (Ustrcmp(hh->address, sender_host_address) == 0)
3674 f.helo_verified = TRUE;
3675 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3677 debug_printf("IP address for %s matches calling address\n"
3678 "Forward DNS security status: %sverified\n",
3679 sender_helo_name, sender_helo_dnssec ? "" : "un");
3685 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3692 /*************************************************
3693 * Send user response message *
3694 *************************************************/
3696 /* This function is passed a default response code and a user message. It calls
3697 smtp_message_code() to check and possibly modify the response code, and then
3698 calls smtp_respond() to transmit the response. I put this into a function
3699 just to avoid a lot of repetition.
3702 code the response code
3703 user_msg the user message
3709 smtp_user_msg(uschar *code, uschar *user_msg)
3712 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3713 smtp_respond(code, len, TRUE, user_msg);
3719 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3721 const uschar *set_id = NULL;
3724 /* Run the checking code, passing the remainder of the command line as
3725 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3726 it as the only set numerical variable. The authenticator may set $auth<n>
3727 and also set other numeric variables. The $auth<n> variables are preferred
3728 nowadays; the numerical variables remain for backwards compatibility.
3730 Afterwards, have a go at expanding the set_id string, even if
3731 authentication failed - for bad passwords it can be useful to log the
3732 userid. On success, require set_id to expand and exist, and put it in
3733 authenticated_id. Save this in permanent store, as the working store gets
3734 reset at HELO, RSET, etc. */
3736 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3738 expand_nlength[0] = 0; /* $0 contains nothing */
3740 rc = (au->info->servercode)(au, smtp_cmd_data);
3741 if (au->set_id) set_id = expand_string(au->set_id);
3742 expand_nmax = -1; /* Reset numeric variables */
3743 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3745 /* The value of authenticated_id is stored in the spool file and printed in
3746 log lines. It must not contain binary zeros or newline characters. In
3747 normal use, it never will, but when playing around or testing, this error
3748 can (did) happen. To guard against this, ensure that the id contains only
3749 printing characters. */
3751 if (set_id) set_id = string_printing(set_id);
3753 /* For the non-OK cases, set up additional logging data if set_id
3757 set_id = set_id && *set_id
3758 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3760 /* Switch on the result */
3765 if (!au->set_id || set_id) /* Complete success */
3767 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3768 sender_host_authenticated = au->name;
3769 sender_host_auth_pubname = au->public_name;
3770 authentication_failed = FALSE;
3771 authenticated_fail_id = NULL; /* Impossible to already be set? */
3774 (sender_host_address ? protocols : protocols_local)
3775 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3776 *s = *ss = US"235 Authentication succeeded";
3777 authenticated_by = au;
3781 /* Authentication succeeded, but we failed to expand the set_id string.
3782 Treat this as a temporary error. */
3784 auth_defer_msg = expand_string_message;
3788 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3789 *s = string_sprintf("435 Unable to authenticate at present%s",
3790 auth_defer_user_msg);
3791 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3792 set_id, auth_defer_msg);
3796 *s = *ss = US"501 Invalid base64 data";
3800 *s = *ss = US"501 Authentication cancelled";
3804 *s = *ss = US"553 Initial data not expected";
3808 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3809 *s = US"535 Incorrect authentication data";
3810 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3814 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3815 *s = US"435 Internal error";
3816 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3817 "check", set_id, rc);
3829 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3832 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3834 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3836 rd = Ustrlen(recipient) + 1;
3837 *recipient = rewrite_address_qualify(*recipient, TRUE);
3840 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3842 log_write(L_smtp_syntax_error,
3843 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3844 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3852 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3855 incomplete_transaction_log(US"QUIT");
3858 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3860 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3865 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3869 smtp_respond(US"221", 3, TRUE, *user_msgp);
3871 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3874 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3877 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3878 smtp_get_connection_info());
3883 smtp_rset_handler(void)
3886 incomplete_transaction_log(US"RSET");
3887 smtp_printf("250 Reset OK\r\n", FALSE);
3888 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3893 /*************************************************
3894 * Initialize for SMTP incoming message *
3895 *************************************************/
3897 /* This function conducts the initial dialogue at the start of an incoming SMTP
3898 message, and builds a list of recipients. However, if the incoming message
3899 is part of a batch (-bS option) a separate function is called since it would
3900 be messy having tests splattered about all over this function. This function
3901 therefore handles the case where interaction is occurring. The input and output
3902 files are set up in smtp_in and smtp_out.
3904 The global recipients_list is set to point to a vector of recipient_item
3905 blocks, whose number is given by recipients_count. This is extended by the
3906 receive_add_recipient() function. The global variable sender_address is set to
3907 the sender's address. The yield is +1 if a message has been successfully
3908 started, 0 if a QUIT command was encountered or the connection was refused from
3909 the particular host, or -1 if the connection was lost.
3913 Returns: > 0 message successfully started (reached DATA)
3914 = 0 QUIT read or end of file reached or call refused
3919 smtp_setup_msg(void)
3922 BOOL toomany = FALSE;
3923 BOOL discarded = FALSE;
3924 BOOL last_was_rej_mail = FALSE;
3925 BOOL last_was_rcpt = FALSE;
3926 rmark reset_point = store_mark();
3928 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3930 /* Reset for start of new message. We allow one RSET not to be counted as a
3931 nonmail command, for those MTAs that insist on sending it between every
3932 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3933 TLS between messages (an Exim client may do this if it has messages queued up
3934 for the host). Note: we do NOT reset AUTH at this point. */
3936 reset_point = smtp_reset(reset_point);
3937 message_ended = END_NOTSTARTED;
3939 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3941 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3942 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3943 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3945 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3948 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3950 had_command_sigterm = 0;
3951 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3953 /* Batched SMTP is handled in a different function. */
3955 if (smtp_batched_input) return smtp_setup_batch_msg();
3957 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3958 value. The values are 2 larger than the required yield of the function. */
3962 const uschar **argv;
3963 uschar *etrn_command;
3964 uschar *etrn_serialize_key;
3966 uschar *log_msg, *smtp_code;
3967 uschar *user_msg = NULL;
3968 uschar *recipient = NULL;
3969 uschar *hello = NULL;
3971 BOOL was_rej_mail = FALSE;
3972 BOOL was_rcpt = FALSE;
3973 void (*oldsignal)(int);
3975 int start, end, sender_domain, recipient_domain;
3978 uschar *orcpt = NULL;
3983 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3984 if ( tls_in.active.sock >= 0
3986 && tls_in.certificate_verified
3987 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3990 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3992 for (auth_instance * au = auths; au; au = au->next)
3993 if (strcmpic(US"tls", au->driver_name) == 0)
3996 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3997 &user_msg, &log_msg)) != OK
3999 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4002 smtp_cmd_data = NULL;
4004 if (smtp_in_auth(au, &s, &ss) == OK)
4005 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4007 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4015 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4016 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4017 US &off, sizeof(off));
4020 switch(smtp_read_command(
4021 #ifndef DISABLE_PIPE_CONNECT
4022 !fl.pipe_connect_acceptable,
4026 GETC_BUFFER_UNLIMITED))
4028 /* The AUTH command is not permitted to occur inside a transaction, and may
4029 occur successfully only once per connection. Actually, that isn't quite
4030 true. When TLS is started, all previous information about a connection must
4031 be discarded, so a new AUTH is permitted at that time.
4033 AUTH may only be used when it has been advertised. However, it seems that
4034 there are clients that send AUTH when it hasn't been advertised, some of
4035 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4036 So there's a get-out that allows this to happen.
4038 AUTH is initially labelled as a "nonmail command" so that one occurrence
4039 doesn't get counted. We change the label here so that multiple failing
4040 AUTHS will eventually hit the nonmail threshold. */
4044 authentication_failed = TRUE;
4045 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4047 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4049 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4050 US"AUTH command used when not advertised");
4053 if (sender_host_authenticated)
4055 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4056 US"already authenticated");
4061 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4062 US"not permitted in mail transaction");
4069 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4070 &user_msg, &log_msg)) != OK
4073 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4077 /* Find the name of the requested authentication mechanism. */
4080 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4082 if (!isalnum(c) && c != '-' && c != '_')
4084 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4085 US"invalid character in authentication mechanism name");
4091 /* If not at the end of the line, we must be at white space. Terminate the
4092 name and move the pointer on to any data that may be present. */
4094 if (*smtp_cmd_data != 0)
4096 *smtp_cmd_data++ = 0;
4097 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4100 /* Search for an authentication mechanism which is configured for use
4101 as a server and which has been advertised (unless, sigh, allow_auth_
4102 unadvertised is set). */
4106 for (au = auths; au; au = au->next)
4107 if (strcmpic(s, au->public_name) == 0 && au->server &&
4108 (au->advertised || f.allow_auth_unadvertised))
4113 c = smtp_in_auth(au, &s, &ss);
4115 smtp_printf("%s\r\n", FALSE, s);
4117 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4118 au->name, host_and_ident(FALSE), ss);
4121 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4122 string_sprintf("%s authentication mechanism not supported", s));
4125 break; /* AUTH_CMD */
4127 /* The HELO/EHLO commands are permitted to appear in the middle of a
4128 session as well as at the beginning. They have the effect of a reset in
4129 addition to their other functions. Their absence at the start cannot be
4130 taken to be an error.
4134 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4135 or 502 failure replies MUST be returned as appropriate. The SMTP
4136 server MUST stay in the same state after transmitting these replies
4137 that it was in before the EHLO was received.
4139 Therefore, we do not do the reset until after checking the command for
4140 acceptability. This change was made for Exim release 4.11. Previously
4141 it did the reset first. */
4154 HELO_EHLO: /* Common code for HELO and EHLO */
4155 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4156 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4158 /* Reject the HELO if its argument was invalid or non-existent. A
4159 successful check causes the argument to be saved in malloc store. */
4161 if (!check_helo(smtp_cmd_data))
4163 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4165 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4166 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4167 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4168 string_printing(smtp_cmd_argument));
4170 if (++synprot_error_count > smtp_max_synprot_errors)
4172 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4173 "syntax or protocol errors (last command was \"%s\", %s)",
4174 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4175 string_from_gstring(s_connhad_log(NULL))
4183 /* If sender_host_unknown is true, we have got here via the -bs interface,
4184 not called from inetd. Otherwise, we are running an IP connection and the
4185 host address will be set. If the helo name is the primary name of this
4186 host and we haven't done a reverse lookup, force one now. If helo_required
4187 is set, ensure that the HELO name matches the actual host. If helo_verify
4188 is set, do the same check, but softly. */
4190 if (!f.sender_host_unknown)
4192 BOOL old_helo_verified = f.helo_verified;
4193 uschar *p = smtp_cmd_data;
4195 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4198 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4199 because otherwise the log can be confusing. */
4201 if ( !sender_host_name
4202 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4203 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4204 (void)host_name_lookup();
4206 /* Rebuild the fullhost info to include the HELO name (and the real name
4207 if it was looked up.) */
4209 host_build_sender_fullhost(); /* Rebuild */
4210 set_process_info("handling%s incoming connection from %s",
4211 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4213 /* Verify if configured. This doesn't give much security, but it does
4214 make some people happy to be able to do it. If helo_required is set,
4215 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4216 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4217 now obsolescent, since the verification can now be requested selectively
4220 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4221 if (fl.helo_required || fl.helo_verify)
4223 BOOL tempfail = !smtp_verify_helo();
4224 if (!f.helo_verified)
4226 if (fl.helo_required)
4228 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4229 tempfail? 451 : 550, hello);
4230 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4231 tempfail? "temporarily " : "",
4232 hello, sender_helo_name, host_and_ident(FALSE));
4233 f.helo_verified = old_helo_verified;
4234 break; /* End of HELO/EHLO processing */
4236 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4237 "helo_try_verify_hosts\n", hello);
4243 /* set up SPF context */
4244 spf_conn_init(sender_helo_name, sender_host_address);
4247 /* Apply an ACL check if one is defined; afterwards, recheck
4248 synchronization in case the client started sending in a delay. */
4251 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4252 &user_msg, &log_msg)) != OK)
4254 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4255 sender_helo_name = NULL;
4256 host_build_sender_fullhost(); /* Rebuild */
4259 #ifndef DISABLE_PIPE_CONNECT
4260 else if (!fl.pipe_connect_acceptable && !check_sync())
4262 else if (!check_sync())
4266 /* Generate an OK reply. The default string includes the ident if present,
4267 and also the IP address if present. Reflecting back the ident is intended
4268 as a deterrent to mail forgers. For maximum efficiency, and also because
4269 some broken systems expect each response to be in a single packet, arrange
4270 that the entire reply is sent in one write(). */
4272 fl.auth_advertised = FALSE;
4273 f.smtp_in_pipelining_advertised = FALSE;
4275 fl.tls_advertised = FALSE;
4277 fl.dsn_advertised = FALSE;
4279 fl.smtputf8_advertised = FALSE;
4282 smtp_code = US"250 "; /* Default response code plus space*/
4285 /* sender_host_name below will be tainted, so save on copy when we hit it */
4286 g = string_get_tainted(24, TRUE);
4287 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4289 smtp_active_hostname,
4290 sender_ident ? sender_ident : US"",
4291 sender_ident ? US" at " : US"",
4292 sender_host_name ? sender_host_name : sender_helo_name);
4294 if (sender_host_address)
4295 g = string_fmt_append(g, " [%s]", sender_host_address);
4298 /* A user-supplied EHLO greeting may not contain more than one line. Note
4299 that the code returned by smtp_message_code() includes the terminating
4300 whitespace character. */
4306 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4307 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4308 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4310 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4311 "newlines: message truncated: %s", string_printing(s));
4314 g = string_cat(NULL, s);
4317 g = string_catn(g, US"\r\n", 2);
4319 /* If we received EHLO, we must create a multiline response which includes
4320 the functions supported. */
4326 /* I'm not entirely happy with this, as an MTA is supposed to check
4327 that it has enough room to accept a message of maximum size before
4328 it sends this. However, there seems little point in not sending it.
4329 The actual size check happens later at MAIL FROM time. By postponing it
4330 till then, VRFY and EXPN can be used after EHLO when space is short. */
4332 if (thismessage_size_limit > 0)
4333 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4334 thismessage_size_limit);
4337 g = string_catn(g, smtp_code, 3);
4338 g = string_catn(g, US"-SIZE\r\n", 7);
4341 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4342 clean; if it has an 8-bit character in its hand, it just sends it. It
4343 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4344 However, some users want this option simply in order to stop MUAs
4345 mangling messages that contain top-bit-set characters. It is therefore
4346 provided as an option. */
4348 if (accept_8bitmime)
4350 g = string_catn(g, smtp_code, 3);
4351 g = string_catn(g, US"-8BITMIME\r\n", 11);
4354 /* Advertise DSN support if configured to do so. */
4355 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4357 g = string_catn(g, smtp_code, 3);
4358 g = string_catn(g, US"-DSN\r\n", 6);
4359 fl.dsn_advertised = TRUE;
4362 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4363 permitted to issue them; a check is made when any host actually tries. */
4367 g = string_catn(g, smtp_code, 3);
4368 g = string_catn(g, US"-ETRN\r\n", 7);
4372 g = string_catn(g, smtp_code, 3);
4373 g = string_catn(g, US"-VRFY\r\n", 7);
4377 g = string_catn(g, smtp_code, 3);
4378 g = string_catn(g, US"-EXPN\r\n", 7);
4381 /* Exim is quite happy with pipelining, so let the other end know that
4382 it is safe to use it, unless advertising is disabled. */
4384 if ( f.pipelining_enable
4385 && verify_check_host(&pipelining_advertise_hosts) == OK)
4387 g = string_catn(g, smtp_code, 3);
4388 g = string_catn(g, US"-PIPELINING\r\n", 13);
4389 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4390 f.smtp_in_pipelining_advertised = TRUE;
4392 #ifndef DISABLE_PIPE_CONNECT
4393 if (fl.pipe_connect_acceptable)
4395 f.smtp_in_early_pipe_advertised = TRUE;
4396 g = string_catn(g, smtp_code, 3);
4397 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4403 /* If any server authentication mechanisms are configured, advertise
4404 them if the current host is in auth_advertise_hosts. The problem with
4405 advertising always is that some clients then require users to
4406 authenticate (and aren't configurable otherwise) even though it may not
4407 be necessary (e.g. if the host is in host_accept_relay).
4409 RFC 2222 states that SASL mechanism names contain only upper case
4410 letters, so output the names in upper case, though we actually recognize
4411 them in either case in the AUTH command. */
4415 && !sender_host_authenticated
4417 && verify_check_host(&auth_advertise_hosts) == OK
4421 for (auth_instance * au = auths; au; au = au->next)
4423 au->advertised = FALSE;
4426 DEBUG(D_auth+D_expand) debug_printf_indent(
4427 "Evaluating advertise_condition for %s %s athenticator\n",
4428 au->name, au->public_name);
4429 if ( !au->advertise_condition
4430 || expand_check_condition(au->advertise_condition, au->name,
4437 g = string_catn(g, smtp_code, 3);
4438 g = string_catn(g, US"-AUTH", 5);
4440 fl.auth_advertised = TRUE;
4443 g = string_catn(g, US" ", 1);
4444 g = string_cat (g, au->public_name);
4445 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4446 au->advertised = TRUE;
4451 if (!first) g = string_catn(g, US"\r\n", 2);
4454 /* RFC 3030 CHUNKING */
4456 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4458 g = string_catn(g, smtp_code, 3);
4459 g = string_catn(g, US"-CHUNKING\r\n", 11);
4460 f.chunking_offered = TRUE;
4461 chunking_state = CHUNKING_OFFERED;
4464 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4465 if it has been included in the binary, and the host matches
4466 tls_advertise_hosts. We must *not* advertise if we are already in a
4467 secure connection. */
4470 if (tls_in.active.sock < 0 &&
4471 verify_check_host(&tls_advertise_hosts) != FAIL)
4473 g = string_catn(g, smtp_code, 3);
4474 g = string_catn(g, US"-STARTTLS\r\n", 11);
4475 fl.tls_advertised = TRUE;
4479 #ifndef DISABLE_PRDR
4480 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4483 g = string_catn(g, smtp_code, 3);
4484 g = string_catn(g, US"-PRDR\r\n", 7);
4489 if ( accept_8bitmime
4490 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4492 g = string_catn(g, smtp_code, 3);
4493 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4494 fl.smtputf8_advertised = TRUE;
4498 /* Finish off the multiline reply with one that is always available. */
4500 g = string_catn(g, smtp_code, 3);
4501 g = string_catn(g, US" HELP\r\n", 7);
4504 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4508 if (tls_in.active.sock >= 0)
4509 (void)tls_write(NULL, g->s, g->ptr,
4510 # ifndef DISABLE_PIPE_CONNECT
4511 fl.pipe_connect_acceptable && pipeline_connect_sends());
4519 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4525 (void) string_from_gstring(g);
4526 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4527 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4528 debug_printf("SMTP>> %s", g->s);
4530 fl.helo_seen = TRUE;
4532 /* Reset the protocol and the state, abandoning any previous message. */
4534 (sender_host_address ? protocols : protocols_local)
4536 ? pextend + (sender_host_authenticated ? pauthed : 0)
4538 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4540 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4541 reset_point = smtp_reset(reset_point);
4543 break; /* HELO/EHLO */
4546 /* The MAIL command requires an address as an operand. All we do
4547 here is to parse it for syntactic correctness. The form "<>" is
4548 a special case which converts into an empty string. The start/end
4549 pointers in the original are not used further for this address, as
4550 it is the canonical extracted address which is all that is kept. */
4554 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4555 was_rej_mail = TRUE; /* Reset if accepted */
4556 env_mail_type_t * mail_args; /* Sanity check & validate args */
4558 if (fl.helo_required && !fl.helo_seen)
4560 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4561 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4562 "HELO/EHLO given", host_and_ident(FALSE));
4568 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4569 US"sender already given");
4573 if (!*smtp_cmd_data)
4575 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4576 US"MAIL must have an address operand");
4580 /* Check to see if the limit for messages per connection would be
4581 exceeded by accepting further messages. */
4583 if (smtp_accept_max_per_connection > 0 &&
4584 smtp_mailcmd_count > smtp_accept_max_per_connection)
4586 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4587 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4588 "messages in one connection", host_and_ident(TRUE));
4592 /* Reset for start of message - even if this is going to fail, we
4593 obviously need to throw away any previous data. */
4595 cancel_cutthrough_connection(TRUE, US"MAIL received");
4596 reset_point = smtp_reset(reset_point);
4598 sender_data = recipient_data = NULL;
4600 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4602 if (fl.esmtp) for(;;)
4604 uschar *name, *value, *end;
4605 unsigned long int size;
4606 BOOL arg_error = FALSE;
4608 if (!extract_option(&name, &value)) break;
4610 for (mail_args = env_mail_type_list;
4611 mail_args->value != ENV_MAIL_OPT_NULL;
4614 if (strcmpic(name, mail_args->name) == 0)
4616 if (mail_args->need_value && strcmpic(value, US"") == 0)
4619 switch(mail_args->value)
4621 /* Handle SIZE= by reading the value. We don't do the check till later,
4622 in order to be able to log the sender address on failure. */
4623 case ENV_MAIL_OPT_SIZE:
4624 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4626 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4628 message_size = (int)size;
4634 /* If this session was initiated with EHLO and accept_8bitmime is set,
4635 Exim will have indicated that it supports the BODY=8BITMIME option. In
4636 fact, it does not support this according to the RFCs, in that it does not
4637 take any special action for forwarding messages containing 8-bit
4638 characters. That is why accept_8bitmime is not the default setting, but
4639 some sites want the action that is provided. We recognize both "8BITMIME"
4640 and "7BIT" as body types, but take no action. */
4641 case ENV_MAIL_OPT_BODY:
4642 if (accept_8bitmime) {
4643 if (strcmpic(value, US"8BITMIME") == 0)
4645 else if (strcmpic(value, US"7BIT") == 0)
4650 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4651 US"invalid data for BODY");
4654 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4660 /* Handle the two DSN options, but only if configured to do so (which
4661 will have caused "DSN" to be given in the EHLO response). The code itself
4662 is included only if configured in at build time. */
4664 case ENV_MAIL_OPT_RET:
4665 if (fl.dsn_advertised)
4667 /* Check if RET has already been set */
4670 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4671 US"RET can be specified once only");
4674 dsn_ret = strcmpic(value, US"HDRS") == 0
4676 : strcmpic(value, US"FULL") == 0
4679 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4680 /* Check for invalid invalid value, and exit with error */
4683 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4684 US"Value for RET is invalid");
4689 case ENV_MAIL_OPT_ENVID:
4690 if (fl.dsn_advertised)
4692 /* Check if the dsn envid has been already set */
4695 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4696 US"ENVID can be specified once only");
4699 dsn_envid = string_copy(value);
4700 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4704 /* Handle the AUTH extension. If the value given is not "<>" and either
4705 the ACL says "yes" or there is no ACL but the sending host is
4706 authenticated, we set it up as the authenticated sender. However, if the
4707 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4708 the condition is met. The value of AUTH is an xtext, which means that +,
4709 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4711 case ENV_MAIL_OPT_AUTH:
4712 if (Ustrcmp(value, "<>") != 0)
4717 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4719 /* Put back terminator overrides for error message */
4722 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4723 US"invalid data for AUTH");
4726 if (!acl_smtp_mailauth)
4728 ignore_msg = US"client not authenticated";
4729 rc = sender_host_authenticated ? OK : FAIL;
4733 ignore_msg = US"rejected by ACL";
4734 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4735 &user_msg, &log_msg);
4741 if (authenticated_by == NULL ||
4742 authenticated_by->mail_auth_condition == NULL ||
4743 expand_check_condition(authenticated_by->mail_auth_condition,
4744 authenticated_by->name, US"authenticator"))
4745 break; /* Accept the AUTH */
4747 ignore_msg = US"server_mail_auth_condition failed";
4748 if (authenticated_id != NULL)
4749 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4750 ignore_msg, authenticated_id);
4755 authenticated_sender = NULL;
4756 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4757 value, host_and_ident(TRUE), ignore_msg);
4760 /* Should only get DEFER or ERROR here. Put back terminator
4761 overrides for error message */
4766 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4773 #ifndef DISABLE_PRDR
4774 case ENV_MAIL_OPT_PRDR:
4776 prdr_requested = TRUE;
4781 case ENV_MAIL_OPT_UTF8:
4782 if (!fl.smtputf8_advertised)
4784 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4785 US"SMTPUTF8 used when not advertised");
4789 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4790 message_smtputf8 = allow_utf8_domains = TRUE;
4791 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4793 int old_pool = store_pool;
4794 store_pool = POOL_PERM;
4795 received_protocol = string_sprintf("utf8%s", received_protocol);
4796 store_pool = old_pool;
4801 /* No valid option. Stick back the terminator characters and break
4802 the loop. Do the name-terminator second as extract_option sets
4803 value==name when it found no equal-sign.
4804 An error for a malformed address will occur. */
4805 case ENV_MAIL_OPT_NULL:
4813 /* Break out of for loop if switch() had bad argument or
4814 when start of the email address is reached */
4815 if (arg_error) break;
4818 /* If we have passed the threshold for rate limiting, apply the current
4819 delay, and update it for next time, provided this is a limited host. */
4821 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4822 verify_check_host(&smtp_ratelimit_hosts) == OK)
4824 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4825 smtp_delay_mail/1000.0);
4826 millisleep((int)smtp_delay_mail);
4827 smtp_delay_mail *= smtp_rlm_factor;
4828 if (smtp_delay_mail > (double)smtp_rlm_limit)
4829 smtp_delay_mail = (double)smtp_rlm_limit;
4832 /* Now extract the address, first applying any SMTP-time rewriting. The
4833 TRUE flag allows "<>" as a sender address. */
4835 raw_sender = rewrite_existflags & rewrite_smtp
4836 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4837 global_rewrite_rules)
4841 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4846 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4850 sender_address = raw_sender;
4852 /* If there is a configured size limit for mail, check that this message
4853 doesn't exceed it. The check is postponed to this point so that the sender
4856 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4858 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4859 log_write(L_size_reject,
4860 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4861 "message too big: size%s=%d max=%d",
4863 host_and_ident(TRUE),
4864 (message_size == INT_MAX)? ">" : "",
4866 thismessage_size_limit);
4867 sender_address = NULL;
4871 /* Check there is enough space on the disk unless configured not to.
4872 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4873 plus the current message - i.e. we accept the message only if it won't
4874 reduce the space below the threshold. Add 5000 to the size to allow for
4875 overheads such as the Received: line and storing of recipients, etc.
4876 By putting the check here, even when SIZE is not given, it allow VRFY
4877 and EXPN etc. to be used when space is short. */
4879 if (!receive_check_fs(
4880 smtp_check_spool_space && message_size >= 0
4881 ? message_size + 5000 : 0))
4883 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4884 sender_address = NULL;
4888 /* If sender_address is unqualified, reject it, unless this is a locally
4889 generated message, or the sending host or net is permitted to send
4890 unqualified addresses - typically local machines behaving as MUAs -
4891 in which case just qualify the address. The flag is set above at the start
4892 of the SMTP connection. */
4894 if (!sender_domain && *sender_address)
4895 if (f.allow_unqualified_sender)
4897 sender_domain = Ustrlen(sender_address) + 1;
4898 sender_address = rewrite_address_qualify(sender_address, FALSE);
4899 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4904 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4906 log_write(L_smtp_syntax_error,
4907 LOG_MAIN|LOG_REJECT,
4908 "unqualified sender rejected: <%s> %s%s",
4910 host_and_ident(TRUE),
4912 sender_address = NULL;
4916 /* Apply an ACL check if one is defined, before responding. Afterwards,
4917 when pipelining is not advertised, do another sync check in case the ACL
4918 delayed and the client started sending in the meantime. */
4922 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4923 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4929 if (rc == OK || rc == DISCARD)
4931 BOOL more = pipeline_response();
4934 smtp_printf("%s%s%s", more, US"250 OK",
4935 #ifndef DISABLE_PRDR
4936 prdr_requested ? US", PRDR Requested" : US"",
4943 #ifndef DISABLE_PRDR
4945 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4947 smtp_user_msg(US"250", user_msg);
4949 smtp_delay_rcpt = smtp_rlr_base;
4950 f.recipients_discarded = (rc == DISCARD);
4951 was_rej_mail = FALSE;
4955 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4956 sender_address = NULL;
4961 /* The RCPT command requires an address as an operand. There may be any
4962 number of RCPT commands, specifying multiple recipients. We build them all
4963 into a data structure. The start/end values given by parse_extract_address
4964 are not used, as we keep only the extracted address. */
4969 was_rcpt = fl.rcpt_in_progress = TRUE;
4971 /* There must be a sender address; if the sender was rejected and
4972 pipelining was advertised, we assume the client was pipelining, and do not
4973 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4974 get the same treatment. */
4976 if (sender_address == NULL)
4978 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4980 smtp_printf("503 sender not yet given\r\n", FALSE);
4981 was_rej_mail = TRUE;
4985 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4986 US"sender not yet given");
4987 was_rcpt = FALSE; /* Not a valid RCPT */
4993 /* Check for an operand */
4995 if (smtp_cmd_data[0] == 0)
4997 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4998 US"RCPT must have an address operand");
5003 /* Set the DSN flags orcpt and dsn_flags from the session*/
5007 if (fl.esmtp) for(;;)
5009 uschar *name, *value;
5011 if (!extract_option(&name, &value))
5014 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5016 /* Check whether orcpt has been already set */
5019 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5020 US"ORCPT can be specified once only");
5023 orcpt = string_copy(value);
5024 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5027 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5029 /* Check if the notify flags have been already set */
5032 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5033 US"NOTIFY can be specified once only");
5036 if (strcmpic(value, US"NEVER") == 0)
5037 dsn_flags |= rf_notify_never;
5044 while (*pp != 0 && *pp != ',') pp++;
5045 if (*pp == ',') *pp++ = 0;
5046 if (strcmpic(p, US"SUCCESS") == 0)
5048 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5049 dsn_flags |= rf_notify_success;
5051 else if (strcmpic(p, US"FAILURE") == 0)
5053 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5054 dsn_flags |= rf_notify_failure;
5056 else if (strcmpic(p, US"DELAY") == 0)
5058 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5059 dsn_flags |= rf_notify_delay;
5063 /* Catch any strange values */
5064 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5065 US"Invalid value for NOTIFY parameter");
5070 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5074 /* Unknown option. Stick back the terminator characters and break
5075 the loop. An error for a malformed address will occur. */
5079 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5086 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5087 as a recipient address */
5089 recipient = rewrite_existflags & rewrite_smtp
5090 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5091 global_rewrite_rules)
5094 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5095 &recipient_domain, FALSE)))
5097 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5102 /* If the recipient address is unqualified, reject it, unless this is a
5103 locally generated message. However, unqualified addresses are permitted
5104 from a configured list of hosts and nets - typically when behaving as
5105 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5106 really. The flag is set at the start of the SMTP connection.
5108 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5109 assumed this meant "reserved local part", but the revision of RFC 821 and
5110 friends now makes it absolutely clear that it means *mailbox*. Consequently
5111 we must always qualify this address, regardless. */
5113 if (!recipient_domain)
5114 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5121 /* Check maximum allowed */
5123 if (rcpt_count > recipients_max && recipients_max > 0)
5125 if (recipients_max_reject)
5128 smtp_printf("552 too many recipients\r\n", FALSE);
5130 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5131 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5136 smtp_printf("452 too many recipients\r\n", FALSE);
5138 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5139 "temporarily rejected: sender=<%s> %s", sender_address,
5140 host_and_ident(TRUE));
5147 /* If we have passed the threshold for rate limiting, apply the current
5148 delay, and update it for next time, provided this is a limited host. */
5150 if (rcpt_count > smtp_rlr_threshold &&
5151 verify_check_host(&smtp_ratelimit_hosts) == OK)
5153 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5154 smtp_delay_rcpt/1000.0);
5155 millisleep((int)smtp_delay_rcpt);
5156 smtp_delay_rcpt *= smtp_rlr_factor;
5157 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5158 smtp_delay_rcpt = (double)smtp_rlr_limit;
5161 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5162 for them. Otherwise, check the access control list for this recipient. As
5163 there may be a delay in this, re-check for a synchronization error
5164 afterwards, unless pipelining was advertised. */
5166 if (f.recipients_discarded)
5169 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5171 && !f.smtp_in_pipelining_advertised && !check_sync())
5174 /* The ACL was happy */
5178 BOOL more = pipeline_response();
5181 smtp_user_msg(US"250", user_msg);
5183 smtp_printf("250 Accepted\r\n", more);
5184 receive_add_recipient(recipient, -1);
5186 /* Set the dsn flags in the recipients_list */
5187 recipients_list[recipients_count-1].orcpt = orcpt;
5188 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5190 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5191 recipients_list[recipients_count-1].orcpt,
5192 recipients_list[recipients_count-1].dsn_flags); */
5195 /* The recipient was discarded */
5197 else if (rc == DISCARD)
5200 smtp_user_msg(US"250", user_msg);
5202 smtp_printf("250 Accepted\r\n", FALSE);
5205 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5206 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5207 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5208 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5209 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5212 /* Either the ACL failed the address, or it was deferred. */
5216 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5217 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5222 /* The DATA command is legal only if it follows successful MAIL FROM
5223 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5224 not counted as a protocol error if it follows RCPT (which must have been
5225 rejected if there are no recipients.) This function is complete when a
5226 valid DATA command is encountered.
5228 Note concerning the code used: RFC 2821 says this:
5230 - If there was no MAIL, or no RCPT, command, or all such commands
5231 were rejected, the server MAY return a "command out of sequence"
5232 (503) or "no valid recipients" (554) reply in response to the
5235 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5236 because it is the same whether pipelining is in use or not.
5238 If all the RCPT commands that precede DATA provoked the same error message
5239 (often indicating some kind of system error), it is helpful to include it
5240 with the DATA rejection (an idea suggested by Tony Finch). */
5247 if (chunking_state != CHUNKING_OFFERED)
5249 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5250 US"BDAT command used when CHUNKING not advertised");
5254 /* grab size, endmarker */
5256 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5258 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5259 US"missing size for BDAT command");
5262 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5263 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5264 chunking_data_left = chunking_datasize;
5265 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5266 (int)chunking_state, chunking_data_left);
5268 /* push the current receive_* function on the "stack", and
5269 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5270 functions to do the dirty work. */
5271 lwr_receive_getc = receive_getc;
5272 lwr_receive_getbuf = receive_getbuf;
5273 lwr_receive_ungetc = receive_ungetc;
5275 receive_getc = bdat_getc;
5276 receive_ungetc = bdat_ungetc;
5287 DATA_BDAT: /* Common code for DATA and BDAT */
5288 #ifndef DISABLE_PIPE_CONNECT
5289 fl.pipe_connect_acceptable = FALSE;
5291 if (!discarded && recipients_count <= 0)
5293 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5295 uschar *code = US"503";
5296 int len = Ustrlen(rcpt_smtp_response);
5297 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5299 /* Responses from smtp_printf() will have \r\n on the end */
5300 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5301 rcpt_smtp_response[len-2] = 0;
5302 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5304 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5305 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5306 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5308 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5309 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5310 ? US"valid RCPT command must precede DATA"
5311 : US"valid RCPT command must precede BDAT");
5313 if (chunking_state > CHUNKING_OFFERED)
5318 if (toomany && recipients_max_reject)
5320 sender_address = NULL; /* This will allow a new MAIL without RSET */
5321 sender_address_unrewritten = NULL;
5322 smtp_printf("554 Too many recipients\r\n", FALSE);
5326 if (chunking_state > CHUNKING_OFFERED)
5327 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5330 /* If there is an ACL, re-check the synchronization afterwards, since the
5331 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5332 to get the DATA command sent. */
5334 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5338 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5339 f.enable_dollar_recipients = TRUE;
5340 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5342 f.enable_dollar_recipients = FALSE;
5343 if (rc == OK && !check_sync())
5347 { /* Either the ACL failed the address, or it was deferred. */
5348 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5354 smtp_user_msg(US"354", user_msg);
5357 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5361 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5362 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5363 US &on, sizeof(on));
5366 message_ended = END_NOTENDED; /* Indicate in middle of data */
5377 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5378 &start, &end, &recipient_domain, FALSE)))
5380 smtp_printf("501 %s\r\n", FALSE, errmess);
5384 if (!recipient_domain)
5385 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5389 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5390 &user_msg, &log_msg)) != OK)
5391 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5395 address_item * addr = deliver_make_addr(address, FALSE);
5397 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5398 -1, -1, NULL, NULL, NULL))
5401 s = string_sprintf("250 <%s> is deliverable", address);
5405 s = (addr->user_message != NULL)?
5406 string_sprintf("451 <%s> %s", address, addr->user_message) :
5407 string_sprintf("451 Cannot resolve <%s> at this time", address);
5411 s = (addr->user_message != NULL)?
5412 string_sprintf("550 <%s> %s", address, addr->user_message) :
5413 string_sprintf("550 <%s> is not deliverable", address);
5414 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5415 smtp_cmd_argument, host_and_ident(TRUE));
5419 smtp_printf("%s\r\n", FALSE, s);
5427 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5429 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5432 BOOL save_log_testing_mode = f.log_testing_mode;
5433 f.address_test_mode = f.log_testing_mode = TRUE;
5434 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5435 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5437 f.address_test_mode = FALSE;
5438 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5447 if (!fl.tls_advertised)
5449 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5450 US"STARTTLS command used when not advertised");
5454 /* Apply an ACL check if one is defined */
5456 if ( acl_smtp_starttls
5457 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5458 &user_msg, &log_msg)) != OK
5461 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5465 /* RFC 2487 is not clear on when this command may be sent, though it
5466 does state that all information previously obtained from the client
5467 must be discarded if a TLS session is started. It seems reasonable to
5468 do an implied RSET when STARTTLS is received. */
5470 incomplete_transaction_log(US"STARTTLS");
5471 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5472 reset_point = smtp_reset(reset_point);
5474 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5476 /* There's an attack where more data is read in past the STARTTLS command
5477 before TLS is negotiated, then assumed to be part of the secure session
5478 when used afterwards; we use segregated input buffers, so are not
5479 vulnerable, but we want to note when it happens and, for sheer paranoia,
5480 ensure that the buffer is "wiped".
5481 Pipelining sync checks will normally have protected us too, unless disabled
5482 by configuration. */
5484 if (receive_smtp_buffered())
5487 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5488 if (tls_in.active.sock < 0)
5489 smtp_inend = smtp_inptr = smtp_inbuffer;
5490 /* and if TLS is already active, tls_server_start() should fail */
5493 /* There is nothing we value in the input buffer and if TLS is successfully
5494 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5495 fresh content into it. The buffer contains arbitrary content from an
5496 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5497 It seems safest to just wipe away the content rather than leave it as a
5498 target to jump to. */
5500 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5502 /* Attempt to start up a TLS session, and if successful, discard all
5503 knowledge that was obtained previously. At least, that's what the RFC says,
5504 and that's what happens by default. However, in order to work round YAEB,
5505 there is an option to remember the esmtp state. Sigh.
5507 We must allow for an extra EHLO command and an extra AUTH command after
5508 STARTTLS that don't add to the nonmail command count. */
5511 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5513 if (!tls_remember_esmtp)
5514 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5515 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5516 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5517 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5518 if (sender_helo_name)
5520 sender_helo_name = NULL;
5521 host_build_sender_fullhost(); /* Rebuild */
5522 set_process_info("handling incoming TLS connection from %s",
5523 host_and_ident(FALSE));
5526 (sender_host_address ? protocols : protocols_local)
5528 ? pextend + (sender_host_authenticated ? pauthed : 0)
5530 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5533 sender_host_auth_pubname = sender_host_authenticated = NULL;
5534 authenticated_id = NULL;
5535 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5536 DEBUG(D_tls) debug_printf("TLS active\n");
5537 break; /* Successful STARTTLS */
5540 (void) smtp_log_tls_fail(s);
5542 /* Some local configuration problem was discovered before actually trying
5543 to do a TLS handshake; give a temporary error. */
5547 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5551 /* Hard failure. Reject everything except QUIT or closed connection. One
5552 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5553 set, but we must still reject all incoming commands. Another is a handshake
5554 failure - and there may some encrypted data still in the pipe to us, which we
5555 see as garbage commands. */
5557 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5558 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5561 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5562 smtp_get_connection_info());
5563 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5567 /* It is perhaps arguable as to which exit ACL should be called here,
5568 but as it is probably a situation that almost never arises, it
5569 probably doesn't matter. We choose to call the real QUIT ACL, which in
5570 some sense is perhaps "right". */
5575 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5576 &log_msg)) == ERROR))
5577 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5580 smtp_respond(US"221", 3, TRUE, user_msg);
5582 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5583 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5584 smtp_get_connection_info());
5589 smtp_printf("554 Security failure\r\n", FALSE);
5592 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5597 /* The ACL for QUIT is provided for gathering statistical information or
5598 similar; it does not affect the response code, but it can supply a custom
5602 smtp_quit_handler(&user_msg, &log_msg);
5608 smtp_rset_handler();
5609 cancel_cutthrough_connection(TRUE, US"RSET received");
5610 reset_point = smtp_reset(reset_point);
5617 smtp_printf("250 OK\r\n", FALSE);
5621 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5622 used, a check will be done for permitted hosts. Show STARTTLS only if not
5623 already in a TLS session and if it would be advertised in the EHLO
5628 smtp_printf("214-Commands supported:\r\n", TRUE);
5632 Ustrcat(buffer, US" AUTH");
5634 if (tls_in.active.sock < 0 &&
5635 verify_check_host(&tls_advertise_hosts) != FAIL)
5636 Ustrcat(buffer, US" STARTTLS");
5638 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5639 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5640 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5641 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5642 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5643 smtp_printf("214%s\r\n", FALSE, buffer);
5649 incomplete_transaction_log(US"connection lost");
5650 smtp_notquit_exit(US"connection-lost", US"421",
5651 US"%s lost input connection", smtp_active_hostname);
5653 /* Don't log by default unless in the middle of a message, as some mailers
5654 just drop the call rather than sending QUIT, and it clutters up the logs.
5657 if (sender_address || recipients_count > 0)
5658 log_write(L_lost_incoming_connection, LOG_MAIN,
5659 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5660 f.sender_host_unknown ? "EOF" : "disconnection",
5661 f.tcp_in_fastopen_logged
5664 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5666 host_and_ident(FALSE), smtp_read_error,
5667 string_timesince(&smtp_connection_start)
5671 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5672 smtp_get_connection_info(),
5673 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5675 string_timesince(&smtp_connection_start)
5686 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5687 US"ETRN is not permitted inside a transaction");
5691 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5692 host_and_ident(FALSE));
5694 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5695 &user_msg, &log_msg)) != OK)
5697 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5701 /* Compute the serialization key for this command. */
5703 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5705 /* If a command has been specified for running as a result of ETRN, we
5706 permit any argument to ETRN. If not, only the # standard form is permitted,
5707 since that is strictly the only kind of ETRN that can be implemented
5708 according to the RFC. */
5710 if (smtp_etrn_command)
5714 etrn_command = smtp_etrn_command;
5715 deliver_domain = smtp_cmd_data;
5716 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5717 US"ETRN processing", &error);
5718 deliver_domain = NULL;
5721 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5723 smtp_printf("458 Internal failure\r\n", FALSE);
5728 /* Else set up to call Exim with the -R option. */
5732 if (*smtp_cmd_data++ != '#')
5734 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5735 US"argument must begin with #");
5738 etrn_command = US"exim -R";
5739 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5740 *queue_name ? 4 : 2,
5741 US"-R", smtp_cmd_data,
5742 US"-MCG", queue_name);
5745 /* If we are host-testing, don't actually do anything. */
5751 debug_printf("ETRN command is: %s\n", etrn_command);
5752 debug_printf("ETRN command execution skipped\n");
5754 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5755 else smtp_user_msg(US"250", user_msg);
5760 /* If ETRN queue runs are to be serialized, check the database to
5761 ensure one isn't already running. */
5763 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5765 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5769 /* Fork a child process and run the command. We don't want to have to
5770 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5771 forking. It should be set that way anyway for external incoming SMTP,
5772 but we save and restore to be tidy. If serialization is required, we
5773 actually run the command in yet another process, so we can wait for it
5774 to complete and then remove the serialization lock. */
5776 oldsignal = signal(SIGCHLD, SIG_IGN);
5778 if ((pid = exim_fork(US"etrn-command")) == 0)
5780 smtp_input = FALSE; /* This process is not associated with the */
5781 (void)fclose(smtp_in); /* SMTP call any more. */
5782 (void)fclose(smtp_out);
5784 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5786 /* If not serializing, do the exec right away. Otherwise, fork down
5787 into another process. */
5789 if ( !smtp_etrn_serialize
5790 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5792 DEBUG(D_exec) debug_print_argv(argv);
5793 exim_nullstd(); /* Ensure std{in,out,err} exist */
5794 execv(CS argv[0], (char *const *)argv);
5795 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5796 etrn_command, strerror(errno));
5797 _exit(EXIT_FAILURE); /* paranoia */
5800 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5801 is, we are in the first subprocess, after forking again. All we can do
5802 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5803 complete, before removing the serialization. */
5806 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5807 "failed: %s", strerror(errno));
5811 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5813 (void)wait(&status);
5814 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5818 enq_end(etrn_serialize_key);
5819 exim_underbar_exit(EXIT_SUCCESS);
5822 /* Back in the top level SMTP process. Check that we started a subprocess
5823 and restore the signal state. */
5827 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5829 smtp_printf("458 Unable to fork process\r\n", FALSE);
5830 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5834 smtp_printf("250 OK\r\n", FALSE);
5836 smtp_user_msg(US"250", user_msg);
5838 signal(SIGCHLD, oldsignal);
5843 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5844 US"unexpected argument data");
5848 /* This currently happens only for NULLs, but could be extended. */
5851 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5852 US"NUL character(s) present (shown as '?')");
5853 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5860 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5861 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5862 c = smtp_inend - smtp_inptr;
5863 if (c > 150) c = 150; /* limit logged amount */
5865 incomplete_transaction_log(US"sync failure");
5866 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5867 "(next input sent too soon: pipelining was%s advertised): "
5868 "rejected \"%s\" %s next input=\"%s\"",
5869 f.smtp_in_pipelining_advertised ? "" : " not",
5870 smtp_cmd_buffer, host_and_ident(TRUE),
5871 string_printing(smtp_inptr));
5872 smtp_notquit_exit(US"synchronization-error", US"554",
5873 US"SMTP synchronization error");
5874 done = 1; /* Pretend eof - drops connection */
5878 case TOO_MANY_NONMAIL_CMD:
5879 s = smtp_cmd_buffer;
5880 while (*s != 0 && !isspace(*s)) s++;
5881 incomplete_transaction_log(US"too many non-mail commands");
5882 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5883 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5884 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5885 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5886 done = 1; /* Pretend eof - drops connection */
5889 #ifdef SUPPORT_PROXY
5890 case PROXY_FAIL_IGNORE_CMD:
5891 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5896 if (unknown_command_count++ >= smtp_max_unknown_commands)
5898 log_write(L_smtp_syntax_error, LOG_MAIN,
5899 "SMTP syntax error in \"%s\" %s %s",
5900 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5901 US"unrecognized command");
5902 incomplete_transaction_log(US"unrecognized command");
5903 smtp_notquit_exit(US"bad-commands", US"500",
5904 US"Too many unrecognized commands");
5906 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5907 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5908 string_printing(smtp_cmd_buffer));
5911 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5912 US"unrecognized command");
5916 /* This label is used by goto's inside loops that want to break out to
5917 the end of the command-processing loop. */
5920 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5921 last_was_rcpt = was_rcpt; /* protocol error handling */
5925 return done - 2; /* Convert yield values */
5931 authres_smtpauth(gstring * g)
5933 if (!sender_host_authenticated)
5936 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5938 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5939 g = authenticated_id
5940 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5941 : string_cat(g, US") reason=x509.auth");
5943 g = authenticated_id
5944 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5945 : string_cat(g, US", no id saved)");
5947 if (authenticated_sender)
5948 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5956 /* End of smtp_in.c */