1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 uschar * smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Recheck synchronization *
324 *************************************************/
326 /* Synchronization checks can never be perfect because a packet may be on its
327 way but not arrived when the check is done. Normally, the checks happen when
328 commands are read: Exim ensures that there is no more input in the input buffer.
329 In normal cases, the response to the command will be fast, and there is no
332 However, for some commands an ACL is run, and that can include delays. In those
333 cases, it is useful to do another check on the input just before sending the
334 response. This also applies at the start of a connection. This function does
335 that check by means of the select() function, as long as the facility is not
336 disabled or inappropriate. A failure of select() is ignored.
338 When there is unwanted input, we read it so that it appears in the log of the
342 Returns: TRUE if all is well; FALSE if there is input pending
346 wouldblock_reading(void)
350 struct timeval tzero;
353 if (tls_in.active.sock >= 0)
354 return !tls_could_read();
357 if (smtp_inptr < smtp_inend)
360 fd = fileno(smtp_in);
365 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
367 if (rc <= 0) return TRUE; /* Not ready to read */
368 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
369 if (rc < 0) return TRUE; /* End of file or error */
378 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
381 return wouldblock_reading();
385 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
386 a reponse with the one following. */
389 pipeline_response(void)
391 if ( !smtp_enforce_sync || !sender_host_address
392 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
395 if (wouldblock_reading()) return FALSE;
396 f.smtp_in_pipelining_used = TRUE;
401 #ifndef DISABLE_PIPE_CONNECT
403 pipeline_connect_sends(void)
405 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
408 if (wouldblock_reading()) return FALSE;
409 f.smtp_in_early_pipe_used = TRUE;
414 /*************************************************
415 * Log incomplete transactions *
416 *************************************************/
418 /* This function is called after a transaction has been aborted by RSET, QUIT,
419 connection drops or other errors. It logs the envelope information received
420 so far in order to preserve address verification attempts.
422 Argument: string to indicate what aborted the transaction
427 incomplete_transaction_log(uschar *what)
429 if (!sender_address /* No transaction in progress */
430 || !LOGGING(smtp_incomplete_transaction))
433 /* Build list of recipients for logging */
435 if (recipients_count > 0)
437 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
438 for (int i = 0; i < recipients_count; i++)
439 raw_recipients[i] = recipients_list[i].address;
440 raw_recipients_count = recipients_count;
443 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
444 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
451 smtp_command_timeout_exit(void)
453 log_write(L_lost_incoming_connection,
454 LOG_MAIN, "SMTP command timeout on%s connection from %s",
455 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
456 if (smtp_batched_input)
457 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
458 smtp_notquit_exit(US"command-timeout", US"421",
459 US"%s: SMTP command timeout - closing connection",
460 smtp_active_hostname);
461 exim_exit(EXIT_FAILURE);
465 smtp_command_sigterm_exit(void)
467 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
468 if (smtp_batched_input)
469 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
470 smtp_notquit_exit(US"signal-exit", US"421",
471 US"%s: Service not available - closing connection", smtp_active_hostname);
472 exim_exit(EXIT_FAILURE);
476 smtp_data_timeout_exit(void)
478 log_write(L_lost_incoming_connection,
479 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
480 sender_fullhost ? sender_fullhost : US"local process", sender_address);
481 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
482 /* Does not return */
486 smtp_data_sigint_exit(void)
488 log_write(0, LOG_MAIN, "%s closed after %s",
489 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
490 receive_bomb_out(US"signal-exit",
491 US"Service not available - SIGTERM or SIGINT received");
492 /* Does not return */
497 /* Refill the buffer, and notify DKIM verification code.
498 Return false for error or EOF.
502 smtp_refill(unsigned lim)
505 if (!smtp_out) return FALSE;
507 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
509 /* Limit amount read, so non-message data is not fed to DKIM.
510 Take care to not touch the safety NUL at the end of the buffer. */
512 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
514 if (smtp_receive_timeout > 0) ALARM_CLR(0);
517 /* Must put the error text in fixed store, because this might be during
518 header reading, where it releases unused store above the header. */
521 if (had_command_timeout) /* set by signal handler */
522 smtp_command_timeout_exit(); /* does not return */
523 if (had_command_sigterm)
524 smtp_command_sigterm_exit();
525 if (had_data_timeout)
526 smtp_data_timeout_exit();
528 smtp_data_sigint_exit();
530 smtp_had_error = save_errno;
531 smtp_read_error = string_copy_perm(
532 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
539 dkim_exim_verify_feed(smtp_inbuffer, rc);
541 smtp_inend = smtp_inbuffer + rc;
542 smtp_inptr = smtp_inbuffer;
546 /*************************************************
547 * SMTP version of getc() *
548 *************************************************/
550 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
551 it flushes the output, and refills the buffer, with a timeout. The signal
552 handler is set appropriately by the calling function. This function is not used
553 after a connection has negotiated itself into an TLS/SSL state.
555 Arguments: lim Maximum amount to read/buffer
556 Returns: the next character or EOF
560 smtp_getc(unsigned lim)
562 if (smtp_inptr >= smtp_inend)
563 if (!smtp_refill(lim))
565 return *smtp_inptr++;
569 smtp_getbuf(unsigned * len)
574 if (smtp_inptr >= smtp_inend)
575 if (!smtp_refill(*len))
576 { *len = 0; return NULL; }
578 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
589 int n = smtp_inend - smtp_inptr;
591 dkim_exim_verify_feed(smtp_inptr, n);
596 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
597 previous BDAT chunk and getting new ones when we run out. Uses the
598 underlying smtp_getc or tls_getc both for that and for getting the
599 (buffered) data byte. EOD signals (an expected) no further data.
600 ERR signals a protocol error, and EOF a closed input stream.
602 Called from read_bdat_smtp() in receive.c for the message body, but also
603 by the headers read loop in receive_msg(); manipulates chunking_state
604 to handle the BDAT command/response.
605 Placed here due to the correlation with the above smtp_getc(), which it wraps,
606 and also by the need to do smtp command/response handling.
608 Arguments: lim (ignored)
609 Returns: the next character or ERR, EOD or EOF
613 bdat_getc(unsigned lim)
615 uschar * user_msg = NULL;
624 if (chunking_data_left > 0)
625 return lwr_receive_getc(chunking_data_left--);
627 receive_getc = lwr_receive_getc;
628 receive_getbuf = lwr_receive_getbuf;
629 receive_ungetc = lwr_receive_ungetc;
631 dkim_save = dkim_collect_input;
632 dkim_collect_input = 0;
635 /* Unless PIPELINING was offered, there should be no next command
636 until after we ack that chunk */
638 if (!f.smtp_in_pipelining_advertised && !check_sync())
640 unsigned n = smtp_inend - smtp_inptr;
643 incomplete_transaction_log(US"sync failure");
644 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
645 "(next input sent too soon: pipelining was not advertised): "
646 "rejected \"%s\" %s next input=\"%s\"%s",
647 smtp_cmd_buffer, host_and_ident(TRUE),
648 string_printing(string_copyn(smtp_inptr, n)),
649 smtp_inend - smtp_inptr > n ? "..." : "");
650 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
651 US"SMTP synchronization error");
652 goto repeat_until_rset;
655 /* If not the last, ack the received chunk. The last response is delayed
656 until after the data ACL decides on it */
658 if (chunking_state == CHUNKING_LAST)
661 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
666 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
667 chunking_state = CHUNKING_OFFERED;
668 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
670 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
671 QUIT, RSET or NOOP but handling them seems obvious */
674 switch(smtp_read_command(TRUE, 1))
677 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
678 US"only BDAT permissible after non-LAST BDAT");
681 switch(smtp_read_command(TRUE, 1))
683 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
684 case EOF_CMD: return EOF;
685 case RSET_CMD: smtp_rset_handler(); return ERR;
686 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
687 US"only RSET accepted now") > 0)
689 goto repeat_until_rset;
693 smtp_quit_handler(&user_msg, &log_msg);
704 smtp_printf("250 OK\r\n", FALSE);
711 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
713 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
714 US"missing size for BDAT command");
717 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
718 ? CHUNKING_LAST : CHUNKING_ACTIVE;
719 chunking_data_left = chunking_datasize;
720 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
721 (int)chunking_state, chunking_data_left);
723 if (chunking_datasize == 0)
724 if (chunking_state == CHUNKING_LAST)
728 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
729 US"zero size for BDAT command");
730 goto repeat_until_rset;
733 receive_getc = bdat_getc;
734 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
735 receive_ungetc = bdat_ungetc;
737 dkim_collect_input = dkim_save;
739 break; /* to top of main loop */
746 bdat_getbuf(unsigned * len)
750 if (chunking_data_left <= 0)
751 { *len = 0; return NULL; }
753 if (*len > chunking_data_left) *len = chunking_data_left;
754 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
755 chunking_data_left -= *len;
760 bdat_flush_data(void)
762 while (chunking_data_left)
764 unsigned n = chunking_data_left;
765 if (!bdat_getbuf(&n)) break;
768 receive_getc = lwr_receive_getc;
769 receive_getbuf = lwr_receive_getbuf;
770 receive_ungetc = lwr_receive_ungetc;
772 if (chunking_state != CHUNKING_LAST)
774 chunking_state = CHUNKING_OFFERED;
775 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
782 /*************************************************
783 * SMTP version of ungetc() *
784 *************************************************/
786 /* Puts a character back in the input buffer. Only ever
792 Returns: the character
806 chunking_data_left++;
807 return lwr_receive_ungetc(ch);
812 /*************************************************
813 * SMTP version of feof() *
814 *************************************************/
816 /* Tests for a previous EOF
819 Returns: non-zero if the eof flag is set
831 /*************************************************
832 * SMTP version of ferror() *
833 *************************************************/
835 /* Tests for a previous read error, and returns with errno
836 restored to what it was when the error was detected.
839 Returns: non-zero if the error flag is set
845 errno = smtp_had_error;
846 return smtp_had_error;
851 /*************************************************
852 * Test for characters in the SMTP buffer *
853 *************************************************/
855 /* Used at the end of a message
864 return smtp_inptr < smtp_inend;
869 /*************************************************
870 * Write formatted string to SMTP channel *
871 *************************************************/
873 /* This is a separate function so that we don't have to repeat everything for
874 TLS support or debugging. It is global so that the daemon and the
875 authentication functions can use it. It does not return any error indication,
876 because major problems such as dropped connections won't show up till an output
877 flush for non-TLS connections. The smtp_fflush() function is available for
878 checking that: for convenience, TLS output errors are remembered here so that
879 they are also picked up later by smtp_fflush().
881 This function is exposed to the local_scan API; do not change the signature.
885 more further data expected
886 ... optional arguments
892 smtp_printf(const char *format, BOOL more, ...)
897 smtp_vprintf(format, more, ap);
901 /* This is split off so that verify.c:respond_printf() can, in effect, call
902 smtp_printf(), bearing in mind that in C a vararg function can't directly
903 call another vararg function, only a function which accepts a va_list.
905 This function is exposed to the local_scan API; do not change the signature.
907 /*XXX consider passing caller-info in, for string_vformat-onward */
910 smtp_vprintf(const char *format, BOOL more, va_list ap)
912 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
915 /* Use taint-unchecked routines for writing into big_buffer, trusting
916 that we'll never expand it. */
918 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
919 string_from_gstring(&gs);
923 uschar *msg_copy, *cr, *end;
924 msg_copy = string_copy(gs.s);
925 end = msg_copy + gs.ptr;
926 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
927 memmove(cr, cr + 1, (end--) - cr);
928 debug_printf("SMTP>> %s", msg_copy);
933 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
934 smtp_closedown(US"Unexpected error");
935 exim_exit(EXIT_FAILURE);
938 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
939 have had the same. Note: this code is also present in smtp_respond(). It would
940 be tidier to have it only in one place, but when it was added, it was easier to
941 do it that way, so as not to have to mess with the code for the RCPT command,
942 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
944 if (fl.rcpt_in_progress)
946 if (rcpt_smtp_response == NULL)
947 rcpt_smtp_response = string_copy(big_buffer);
948 else if (fl.rcpt_smtp_response_same &&
949 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
950 fl.rcpt_smtp_response_same = FALSE;
951 fl.rcpt_in_progress = FALSE;
954 /* Now write the string */
958 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
960 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
962 smtp_write_error = -1;
967 /*************************************************
968 * Flush SMTP out and check for error *
969 *************************************************/
971 /* This function isn't currently used within Exim (it detects errors when it
972 tries to read the next SMTP input), but is available for use in local_scan().
973 It flushes the output and checks for errors.
976 Returns: 0 for no error; -1 after an error
982 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
986 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
988 (fflush(smtp_out) != 0)
990 smtp_write_error = -1;
992 return smtp_write_error;
997 /*************************************************
998 * SMTP command read timeout *
999 *************************************************/
1001 /* Signal handler for timing out incoming SMTP commands. This attempts to
1004 Argument: signal number (SIGALRM)
1009 command_timeout_handler(int sig)
1011 had_command_timeout = sig;
1016 /*************************************************
1017 * SIGTERM received *
1018 *************************************************/
1020 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1022 Argument: signal number (SIGTERM)
1027 command_sigterm_handler(int sig)
1029 had_command_sigterm = sig;
1035 #ifdef SUPPORT_PROXY
1036 /*************************************************
1037 * 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 #ifndef DISABLE_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, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
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 recipient_verify_failure = NULL;
2072 deliver_localpart_parent = deliver_localpart_orig = NULL;
2073 deliver_domain_parent = deliver_domain_orig = NULL;
2074 callout_address = NULL;
2075 submission_name = NULL; /* Can be set by ACL */
2076 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2077 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2078 sender_verified_list = NULL; /* No senders verified */
2079 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2080 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2082 authenticated_sender = NULL;
2083 #ifdef EXPERIMENTAL_BRIGHTMAIL
2085 bmi_verdicts = NULL;
2087 dnslist_domain = dnslist_matched = NULL;
2089 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2090 spf_result_guessed = FALSE;
2092 #ifndef DISABLE_DKIM
2093 dkim_cur_signer = dkim_signers =
2094 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2095 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2096 f.dkim_disable_verify = FALSE;
2097 dkim_collect_input = 0;
2098 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2099 dkim_key_length = 0;
2101 #ifdef SUPPORT_DMARC
2102 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2103 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2104 dmarc_used_domain = NULL;
2106 #ifdef EXPERIMENTAL_ARC
2107 arc_state = arc_state_reason = NULL;
2108 arc_received_instance = 0;
2112 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2113 #ifndef DISABLE_PRDR
2114 prdr_requested = FALSE;
2117 message_smtputf8 = FALSE;
2119 body_linecount = body_zerocount = 0;
2121 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2122 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2123 /* Note that ratelimiters_conn persists across resets. */
2125 /* Reset message ACL variables */
2129 /* The message body variables use malloc store. They may be set if this is
2130 not the first message in an SMTP session and the previous message caused them
2131 to be referenced in an ACL. */
2135 store_free(message_body);
2136 message_body = NULL;
2139 if (message_body_end)
2141 store_free(message_body_end);
2142 message_body_end = NULL;
2145 /* Warning log messages are also saved in malloc store. They are saved to avoid
2146 repetition in the same message, but it seems right to repeat them for different
2149 while (acl_warn_logged)
2151 string_item *this = acl_warn_logged;
2152 acl_warn_logged = acl_warn_logged->next;
2155 store_reset(reset_point);
2156 return store_mark();
2163 /*************************************************
2164 * Initialize for incoming batched SMTP message *
2165 *************************************************/
2167 /* This function is called from smtp_setup_msg() in the case when
2168 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2169 of messages in one file with SMTP commands between them. All errors must be
2170 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2171 relevant. After an error on a sender, or an invalid recipient, the remainder
2172 of the message is skipped. The value of received_protocol is already set.
2175 Returns: > 0 message successfully started (reached DATA)
2176 = 0 QUIT read or end of file reached
2177 < 0 should not occur
2181 smtp_setup_batch_msg(void)
2184 rmark reset_point = store_mark();
2186 /* Save the line count at the start of each transaction - single commands
2187 like HELO and RSET count as whole transactions. */
2189 bsmtp_transaction_linecount = receive_linecount;
2191 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2193 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2194 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2196 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2197 value. The values are 2 larger than the required yield of the function. */
2202 uschar *recipient = NULL;
2203 int start, end, sender_domain, recipient_domain;
2205 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2207 /* The HELO/EHLO commands set sender_address_helo if they have
2208 valid data; otherwise they are ignored, except that they do
2209 a reset of the state. */
2214 check_helo(smtp_cmd_data);
2218 cancel_cutthrough_connection(TRUE, US"RSET received");
2219 reset_point = smtp_reset(reset_point);
2220 bsmtp_transaction_linecount = receive_linecount;
2224 /* The MAIL FROM command requires an address as an operand. All we
2225 do here is to parse it for syntactic correctness. The form "<>" is
2226 a special case which converts into an empty string. The start/end
2227 pointers in the original are not used further for this address, as
2228 it is the canonical extracted address which is all that is kept. */
2231 smtp_mailcmd_count++; /* Count for no-mail log */
2232 if (sender_address != NULL)
2233 /* The function moan_smtp_batch() does not return. */
2234 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2236 if (smtp_cmd_data[0] == 0)
2237 /* The function moan_smtp_batch() does not return. */
2238 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2240 /* Reset to start of message */
2242 cancel_cutthrough_connection(TRUE, US"MAIL received");
2243 reset_point = smtp_reset(reset_point);
2245 /* Apply SMTP rewrite */
2247 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2248 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2249 US"", global_rewrite_rules) : smtp_cmd_data;
2251 /* Extract the address; the TRUE flag allows <> as valid */
2254 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2258 /* The function moan_smtp_batch() does not return. */
2259 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2261 sender_address = string_copy(raw_sender);
2263 /* Qualify unqualified sender addresses if permitted to do so. */
2266 && sender_address[0] != 0 && sender_address[0] != '@')
2267 if (f.allow_unqualified_sender)
2269 sender_address = rewrite_address_qualify(sender_address, FALSE);
2270 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2271 "and rewritten\n", raw_sender);
2273 /* The function moan_smtp_batch() does not return. */
2275 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2280 /* The RCPT TO command requires an address as an operand. All we do
2281 here is to parse it for syntactic correctness. There may be any number
2282 of RCPT TO commands, specifying multiple senders. We build them all into
2283 a data structure that is in argc/argv format. The start/end values
2284 given by parse_extract_address are not used, as we keep only the
2285 extracted address. */
2288 if (!sender_address)
2289 /* The function moan_smtp_batch() does not return. */
2290 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2292 if (smtp_cmd_data[0] == 0)
2293 /* The function moan_smtp_batch() does not return. */
2294 moan_smtp_batch(smtp_cmd_buffer,
2295 "501 RCPT TO must have an address operand");
2297 /* Check maximum number allowed */
2299 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2300 /* The function moan_smtp_batch() does not return. */
2301 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2302 recipients_max_reject? "552": "452");
2304 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2305 recipient address */
2307 recipient = rewrite_existflags & rewrite_smtp
2308 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2309 global_rewrite_rules)
2312 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2313 &recipient_domain, FALSE);
2316 /* The function moan_smtp_batch() does not return. */
2317 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2319 /* If the recipient address is unqualified, qualify it if permitted. Then
2320 add it to the list of recipients. */
2322 if (!recipient_domain)
2323 if (f.allow_unqualified_recipient)
2325 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2327 recipient = rewrite_address_qualify(recipient, TRUE);
2329 /* The function moan_smtp_batch() does not return. */
2331 moan_smtp_batch(smtp_cmd_buffer,
2332 "501 recipient address must contain a domain");
2334 receive_add_recipient(recipient, -1);
2338 /* The DATA command is legal only if it follows successful MAIL FROM
2339 and RCPT TO commands. This function is complete when a valid DATA
2340 command is encountered. */
2343 if (!sender_address || recipients_count <= 0)
2344 /* The function moan_smtp_batch() does not return. */
2345 if (!sender_address)
2346 moan_smtp_batch(smtp_cmd_buffer,
2347 "503 MAIL FROM:<sender> command must precede DATA");
2349 moan_smtp_batch(smtp_cmd_buffer,
2350 "503 RCPT TO:<recipient> must precede DATA");
2353 done = 3; /* DATA successfully achieved */
2354 message_ended = END_NOTENDED; /* Indicate in middle of message */
2359 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2366 bsmtp_transaction_linecount = receive_linecount;
2377 /* The function moan_smtp_batch() does not return. */
2378 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2383 /* The function moan_smtp_batch() does not return. */
2384 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2389 /* The function moan_smtp_batch() does not return. */
2390 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2395 return done - 2; /* Convert yield values */
2403 smtp_log_tls_fail(uschar * errstr)
2405 uschar * conn_info = smtp_get_connection_info();
2407 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2408 /* I'd like to get separated H= here, but too hard for now */
2410 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2424 socklen_t len = sizeof(is_fastopen);
2426 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2427 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2429 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2434 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2435 f.tcp_in_fastopen = TRUE;
2438 else DEBUG(D_receive)
2439 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2441 # elif defined(TCP_INFO)
2442 struct tcp_info tinfo;
2443 socklen_t len = sizeof(tinfo);
2445 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2446 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2447 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2450 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2451 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2455 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2458 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2459 f.tcp_in_fastopen = TRUE;
2461 else DEBUG(D_receive)
2462 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2468 /*************************************************
2469 * Start an SMTP session *
2470 *************************************************/
2472 /* This function is called at the start of an SMTP session. Thereafter,
2473 smtp_setup_msg() is called to initiate each separate message. This
2474 function does host-specific testing, and outputs the banner line.
2477 Returns: FALSE if the session can not continue; something has
2478 gone wrong, or the connection to the host is blocked
2482 smtp_start_session(void)
2485 uschar *user_msg, *log_msg;
2490 gettimeofday(&smtp_connection_start, NULL);
2491 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2492 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2495 /* Default values for certain variables */
2497 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2498 smtp_mailcmd_count = 0;
2499 count_nonmail = TRUE_UNSET;
2500 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2501 smtp_delay_mail = smtp_rlm_base;
2502 fl.auth_advertised = FALSE;
2503 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2504 f.pipelining_enable = TRUE;
2505 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2506 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2508 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2509 authentication settings from -oMaa to remain in force. */
2511 if (!host_checking && !f.sender_host_notsocket)
2512 sender_host_auth_pubname = sender_host_authenticated = NULL;
2513 authenticated_by = NULL;
2516 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2517 tls_in.ourcert = tls_in.peercert = NULL;
2519 tls_in.ocsp = OCSP_NOT_REQ;
2520 fl.tls_advertised = FALSE;
2522 fl.dsn_advertised = FALSE;
2524 fl.smtputf8_advertised = FALSE;
2527 /* Reset ACL connection variables */
2531 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2533 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2535 smtp_cmd_buffer[0] = 0;
2536 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2538 /* For batched input, the protocol setting can be overridden from the
2539 command line by a trusted caller. */
2541 if (smtp_batched_input)
2543 if (!received_protocol) received_protocol = US"local-bsmtp";
2546 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2547 reset later if any of EHLO/AUTH/STARTTLS are received. */
2551 (sender_host_address ? protocols : protocols_local) [pnormal];
2553 /* Set up the buffer for inputting using direct read() calls, and arrange to
2554 call the local functions instead of the standard C ones. Place a NUL at the
2555 end of the buffer to safety-stop C-string reads from it. */
2557 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2558 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2559 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2561 receive_getc = smtp_getc;
2562 receive_getbuf = smtp_getbuf;
2563 receive_get_cache = smtp_get_cache;
2564 receive_ungetc = smtp_ungetc;
2565 receive_feof = smtp_feof;
2566 receive_ferror = smtp_ferror;
2567 receive_smtp_buffered = smtp_buffered;
2568 smtp_inptr = smtp_inend = smtp_inbuffer;
2569 smtp_had_eof = smtp_had_error = 0;
2571 /* Set up the message size limit; this may be host-specific */
2573 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2574 if (expand_string_message)
2576 if (thismessage_size_limit == -1)
2577 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2578 "%s", expand_string_message);
2580 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2581 "%s", expand_string_message);
2582 smtp_closedown(US"Temporary local problem - please try later");
2586 /* When a message is input locally via the -bs or -bS options, sender_host_
2587 unknown is set unless -oMa was used to force an IP address, in which case it
2588 is checked like a real remote connection. When -bs is used from inetd, this
2589 flag is not set, causing the sending host to be checked. The code that deals
2590 with IP source routing (if configured) is never required for -bs or -bS and
2591 the flag sender_host_notsocket is used to suppress it.
2593 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2594 reserve for certain hosts and/or networks. */
2596 if (!f.sender_host_unknown)
2599 BOOL reserved_host = FALSE;
2601 /* Look up IP options (source routing info) on the socket if this is not an
2602 -oMa "host", and if any are found, log them and drop the connection.
2604 Linux (and others now, see below) is different to everyone else, so there
2605 has to be some conditional compilation here. Versions of Linux before 2.1.15
2606 used a structure whose name was "options". Somebody finally realized that
2607 this name was silly, and it got changed to "ip_options". I use the
2608 newer name here, but there is a fudge in the script that sets up os.h
2609 to define a macro in older Linux systems.
2611 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2612 glibc 2, which has chosen ip_opts for the structure name. This is now
2613 really a glibc thing rather than a Linux thing, so the condition name
2614 has been changed to reflect this. It is relevant also to GNU/Hurd.
2616 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2617 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2618 a special macro defined in the os.h file.
2620 Some DGUX versions on older hardware appear not to support IP options at
2621 all, so there is now a general macro which can be set to cut out this
2624 How to do this properly in IPv6 is not yet known. */
2626 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2628 #ifdef GLIBC_IP_OPTIONS
2629 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2634 #elif defined DARWIN_IP_OPTIONS
2640 if (!host_checking && !f.sender_host_notsocket)
2643 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2644 struct ip_options *ipopt = store_get(optlen, FALSE);
2646 struct ip_opts ipoptblock;
2647 struct ip_opts *ipopt = &ipoptblock;
2648 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2650 struct ipoption ipoptblock;
2651 struct ipoption *ipopt = &ipoptblock;
2652 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2655 /* Occasional genuine failures of getsockopt() have been seen - for
2656 example, "reset by peer". Therefore, just log and give up on this
2657 call, unless the error is ENOPROTOOPT. This error is given by systems
2658 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2659 of writing. So for that error, carry on - we just can't do an IP options
2662 DEBUG(D_receive) debug_printf("checking for IP options\n");
2664 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2667 if (errno != ENOPROTOOPT)
2669 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2670 host_and_ident(FALSE), strerror(errno));
2671 smtp_printf("451 SMTP service not available\r\n", FALSE);
2676 /* Deal with any IP options that are set. On the systems I have looked at,
2677 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2678 more logging data than will fit in big_buffer. Nevertheless, after somebody
2679 questioned this code, I've added in some paranoid checking. */
2681 else if (optlen > 0)
2683 uschar *p = big_buffer;
2684 uschar *pend = big_buffer + big_buffer_size;
2687 struct in_addr addr;
2690 uschar *optstart = US (ipopt->__data);
2692 uschar *optstart = US (ipopt->ip_opts);
2694 uschar *optstart = US (ipopt->ipopt_list);
2697 DEBUG(D_receive) debug_printf("IP options exist\n");
2699 Ustrcpy(p, "IP options on incoming call:");
2702 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2715 if (!string_format(p, pend-p, " %s [@%s",
2716 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2718 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2720 inet_ntoa(ipopt->ip_dst)))
2722 inet_ntoa(ipopt->ipopt_dst)))
2730 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2732 while (optcount-- > 0)
2734 memcpy(&addr, adptr, sizeof(addr));
2735 if (!string_format(p, pend - p - 1, "%s%s",
2736 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2742 adptr += sizeof(struct in_addr);
2750 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2753 for (int i = 0; i < opt[1]; i++)
2754 p += sprintf(CS p, "%2.2x ", opt[i]);
2762 log_write(0, LOG_MAIN, "%s", big_buffer);
2764 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2766 log_write(0, LOG_MAIN|LOG_REJECT,
2767 "connection from %s refused (IP options)", host_and_ident(FALSE));
2769 smtp_printf("554 SMTP service not available\r\n", FALSE);
2773 /* Length of options = 0 => there are no options */
2775 else DEBUG(D_receive) debug_printf("no IP options found\n");
2777 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2779 /* Set keep-alive in socket options. The option is on by default. This
2780 setting is an attempt to get rid of some hanging connections that stick in
2781 read() when the remote end (usually a dialup) goes away. */
2783 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2784 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2786 /* If the current host matches host_lookup, set the name by doing a
2787 reverse lookup. On failure, sender_host_name will be NULL and
2788 host_lookup_failed will be TRUE. This may or may not be serious - optional
2791 if (verify_check_host(&host_lookup) == OK)
2793 (void)host_name_lookup();
2794 host_build_sender_fullhost();
2797 /* Delay this until we have the full name, if it is looked up. */
2799 set_process_info("handling incoming connection from %s",
2800 host_and_ident(FALSE));
2802 /* Expand smtp_receive_timeout, if needed */
2804 if (smtp_receive_timeout_s)
2807 if ( !(exp = expand_string(smtp_receive_timeout_s))
2809 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2811 log_write(0, LOG_MAIN|LOG_PANIC,
2812 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2815 /* Test for explicit connection rejection */
2817 if (verify_check_host(&host_reject_connection) == OK)
2819 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2820 "from %s (host_reject_connection)", host_and_ident(FALSE));
2821 smtp_printf("554 SMTP service not available\r\n", FALSE);
2825 /* Test with TCP Wrappers if so configured. There is a problem in that
2826 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2827 such as disks dying. In these cases, it is desirable to reject with a 4xx
2828 error instead of a 5xx error. There isn't a "right" way to detect such
2829 problems. The following kludge is used: errno is zeroed before calling
2830 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2831 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2834 #ifdef USE_TCP_WRAPPERS
2836 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2837 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2838 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2839 expand_string_message);
2841 if (!hosts_ctl(tcp_wrappers_name,
2842 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2843 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2844 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2846 if (errno == 0 || errno == ENOENT)
2848 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2849 log_write(L_connection_reject,
2850 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2851 "(tcp wrappers)", host_and_ident(FALSE));
2852 smtp_printf("554 SMTP service not available\r\n", FALSE);
2856 int save_errno = errno;
2857 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2858 "errno value %d\n", save_errno);
2859 log_write(L_connection_reject,
2860 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2861 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2862 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2868 /* Check for reserved slots. The value of smtp_accept_count has already been
2869 incremented to include this process. */
2871 if (smtp_accept_max > 0 &&
2872 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2874 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2876 log_write(L_connection_reject,
2877 LOG_MAIN, "temporarily refused connection from %s: not in "
2878 "reserve list: connected=%d max=%d reserve=%d%s",
2879 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2880 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2881 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2882 "please try again later\r\n", FALSE, smtp_active_hostname);
2885 reserved_host = TRUE;
2888 /* If a load level above which only messages from reserved hosts are
2889 accepted is set, check the load. For incoming calls via the daemon, the
2890 check is done in the superior process if there are no reserved hosts, to
2891 save a fork. In all cases, the load average will already be available
2892 in a global variable at this point. */
2894 if (smtp_load_reserve >= 0 &&
2895 load_average > smtp_load_reserve &&
2897 verify_check_host(&smtp_reserve_hosts) != OK)
2899 log_write(L_connection_reject,
2900 LOG_MAIN, "temporarily refused connection from %s: not in "
2901 "reserve list and load average = %.2f", host_and_ident(FALSE),
2902 (double)load_average/1000.0);
2903 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2904 smtp_active_hostname);
2908 /* Determine whether unqualified senders or recipients are permitted
2909 for this host. Unfortunately, we have to do this every time, in order to
2910 set the flags so that they can be inspected when considering qualifying
2911 addresses in the headers. For a site that permits no qualification, this
2912 won't take long, however. */
2914 f.allow_unqualified_sender =
2915 verify_check_host(&sender_unqualified_hosts) == OK;
2917 f.allow_unqualified_recipient =
2918 verify_check_host(&recipient_unqualified_hosts) == OK;
2920 /* Determine whether HELO/EHLO is required for this host. The requirement
2921 can be hard or soft. */
2923 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2924 if (!fl.helo_required)
2925 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2927 /* Determine whether this hosts is permitted to send syntactic junk
2928 after a HELO or EHLO command. */
2930 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2933 /* For batch SMTP input we are now done. */
2935 if (smtp_batched_input) return TRUE;
2937 /* If valid Proxy Protocol source is connecting, set up session.
2938 * Failure will not allow any SMTP function other than QUIT. */
2940 #ifdef SUPPORT_PROXY
2941 proxy_session = FALSE;
2942 f.proxy_session_failed = FALSE;
2943 if (check_proxy_protocol_host())
2944 setup_proxy_protocol_host();
2947 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2948 smtps port for use with older style SSL MTAs. */
2951 if (tls_in.on_connect)
2953 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2954 return smtp_log_tls_fail(user_msg);
2955 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2959 /* Run the connect ACL if it exists */
2962 if (acl_smtp_connect)
2965 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2968 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2973 /* Output the initial message for a two-way SMTP connection. It may contain
2974 newlines, which then cause a multi-line response to be given. */
2976 code = US"220"; /* Default status code */
2977 esc = US""; /* Default extended status code */
2978 esclen = 0; /* Length of esc */
2982 if (!(s = expand_string(smtp_banner)))
2983 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2984 "failed: %s", smtp_banner, expand_string_message);
2990 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2994 esclen = codelen - 4;
2998 /* Remove any terminating newlines; might as well remove trailing space too */
3001 while (p > s && isspace(p[-1])) p--;
3004 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3005 is all contained in a single IP packet. The original code wrote out the
3006 greeting using several calls to fprint/fputc, and on busy servers this could
3007 cause it to be split over more than one packet - which caused CC:Mail to fall
3008 over when it got the second part of the greeting after sending its first
3009 command. Sigh. To try to avoid this, build the complete greeting message
3010 first, and output it in one fell swoop. This gives a better chance of it
3011 ending up as a single packet. */
3013 ss = string_get(256);
3016 do /* At least once, in case we have an empty string */
3019 uschar *linebreak = Ustrchr(p, '\n');
3020 ss = string_catn(ss, code, 3);
3024 ss = string_catn(ss, US" ", 1);
3028 len = linebreak - p;
3029 ss = string_catn(ss, US"-", 1);
3031 ss = string_catn(ss, esc, esclen);
3032 ss = string_catn(ss, p, len);
3033 ss = string_catn(ss, US"\r\n", 2);
3039 /* Before we write the banner, check that there is no input pending, unless
3040 this synchronisation check is disabled. */
3042 #ifndef DISABLE_PIPE_CONNECT
3043 fl.pipe_connect_acceptable =
3044 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3047 if (fl.pipe_connect_acceptable)
3048 f.smtp_in_early_pipe_used = TRUE;
3054 unsigned n = smtp_inend - smtp_inptr;
3055 if (n > 128) n = 128;
3057 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3058 "synchronization error (input sent without waiting for greeting): "
3059 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3060 string_printing(string_copyn(smtp_inptr, n)));
3061 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3065 /* Now output the banner */
3066 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3069 #ifndef DISABLE_PIPE_CONNECT
3070 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3074 string_from_gstring(ss));
3076 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3077 handshake arrived. If so we must have managed a TFO. */
3080 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3090 /*************************************************
3091 * Handle SMTP syntax and protocol errors *
3092 *************************************************/
3094 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3095 to do so. Then transmit the error response. The return value depends on the
3096 number of syntax and protocol errors in this SMTP session.
3099 type error type, given as a log flag bit
3100 code response code; <= 0 means don't send a response
3101 data data to reflect in the response (can be NULL)
3102 errmess the error message
3104 Returns: -1 limit of syntax/protocol errors NOT exceeded
3105 +1 limit of syntax/protocol errors IS exceeded
3107 These values fit in with the values of the "done" variable in the main
3108 processing loop in smtp_setup_msg(). */
3111 synprot_error(int type, int code, uschar *data, uschar *errmess)
3115 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3116 type == L_smtp_syntax_error ? "syntax" : "protocol",
3117 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3119 if (++synprot_error_count > smtp_max_synprot_errors)
3122 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3123 "syntax or protocol errors (last command was \"%s\", %s)",
3124 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3125 string_from_gstring(s_connhad_log(NULL))
3131 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3132 data ? data : US"", data ? US": " : US"", errmess);
3134 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3143 /*************************************************
3144 * Send SMTP response, possibly multiline *
3145 *************************************************/
3147 /* There are, it seems, broken clients out there that cannot handle multiline
3148 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3149 output nothing for non-final calls, and only the first line for anything else.
3152 code SMTP code, may involve extended status codes
3153 codelen length of smtp code; if > 4 there's an ESC
3154 final FALSE if the last line isn't the final line
3155 msg message text, possibly containing newlines
3161 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3166 if (!final && f.no_multiline_responses) return;
3171 esclen = codelen - 4;
3174 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3175 have had the same. Note: this code is also present in smtp_printf(). It would
3176 be tidier to have it only in one place, but when it was added, it was easier to
3177 do it that way, so as not to have to mess with the code for the RCPT command,
3178 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3180 if (fl.rcpt_in_progress)
3182 if (rcpt_smtp_response == NULL)
3183 rcpt_smtp_response = string_copy(msg);
3184 else if (fl.rcpt_smtp_response_same &&
3185 Ustrcmp(rcpt_smtp_response, msg) != 0)
3186 fl.rcpt_smtp_response_same = FALSE;
3187 fl.rcpt_in_progress = FALSE;
3190 /* Now output the message, splitting it up into multiple lines if necessary.
3191 We only handle pipelining these responses as far as nonfinal/final groups,
3192 not the whole MAIL/RCPT/DATA response set. */
3196 uschar *nl = Ustrchr(msg, '\n');
3199 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3202 else if (nl[1] == 0 || f.no_multiline_responses)
3204 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3205 (int)(nl - msg), msg);
3210 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3212 Uskip_whitespace(&msg);
3220 /*************************************************
3221 * Parse user SMTP message *
3222 *************************************************/
3224 /* This function allows for user messages overriding the response code details
3225 by providing a suitable response code string at the start of the message
3226 user_msg. Check the message for starting with a response code and optionally an
3227 extended status code. If found, check that the first digit is valid, and if so,
3228 change the code pointer and length to use the replacement. An invalid code
3229 causes a panic log; in this case, if the log messages is the same as the user
3230 message, we must also adjust the value of the log message to show the code that
3231 is actually going to be used (the original one).
3233 This function is global because it is called from receive.c as well as within
3236 Note that the code length returned includes the terminating whitespace
3237 character, which is always included in the regex match.
3240 code SMTP code, may involve extended status codes
3241 codelen length of smtp code; if > 4 there's an ESC
3243 log_msg optional log message, to be adjusted with the new SMTP code
3244 check_valid if true, verify the response code
3250 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3256 if (!msg || !*msg) return;
3258 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3259 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3261 if (check_valid && (*msg)[0] != (*code)[0])
3263 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3264 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3265 if (log_msg != NULL && *log_msg == *msg)
3266 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3271 *codelen = ovector[1]; /* Includes final space */
3273 *msg += ovector[1]; /* Chop the code off the message */
3280 /*************************************************
3281 * Handle an ACL failure *
3282 *************************************************/
3284 /* This function is called when acl_check() fails. As well as calls from within
3285 this module, it is called from receive.c for an ACL after DATA. It sorts out
3286 logging the incident, and sends the error response. A message containing
3287 newlines is turned into a multiline SMTP response, but for logging, only the
3290 There's a table of default permanent failure response codes to use in
3291 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3292 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3293 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3294 state, because there are broken clients that try VRFY before RCPT. A 5xx
3295 response should be given only when the address is positively known to be
3296 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3297 no explicit code, but if there is one we let it know best.
3298 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3300 From Exim 4.63, it is possible to override the response code details by
3301 providing a suitable response code string at the start of the message provided
3302 in user_msg. The code's first digit is checked for validity.
3305 where where the ACL was called from
3307 user_msg a message that can be included in an SMTP response
3308 log_msg a message for logging
3310 Returns: 0 in most cases
3311 2 if the failure code was FAIL_DROP, in which case the
3312 SMTP connection should be dropped (this value fits with the
3313 "done" variable in smtp_setup_msg() below)
3317 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3319 BOOL drop = rc == FAIL_DROP;
3323 uschar *sender_info = US"";
3325 #ifdef WITH_CONTENT_SCAN
3326 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3328 where == ACL_WHERE_PREDATA ? US"DATA" :
3329 where == ACL_WHERE_DATA ? US"after DATA" :
3330 #ifndef DISABLE_PRDR
3331 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3334 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3335 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3337 if (drop) rc = FAIL;
3339 /* Set the default SMTP code, and allow a user message to change it. */
3341 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3342 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3343 where != ACL_WHERE_VRFY);
3345 /* We used to have sender_address here; however, there was a bug that was not
3346 updating sender_address after a rewrite during a verify. When this bug was
3347 fixed, sender_address at this point became the rewritten address. I'm not sure
3348 this is what should be logged, so I've changed to logging the unrewritten
3349 address to retain backward compatibility. */
3351 #ifndef WITH_CONTENT_SCAN
3352 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3354 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3357 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3358 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3359 sender_host_authenticated ? US" A=" : US"",
3360 sender_host_authenticated ? sender_host_authenticated : US"",
3361 sender_host_authenticated && authenticated_id ? US":" : US"",
3362 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3366 /* If there's been a sender verification failure with a specific message, and
3367 we have not sent a response about it yet, do so now, as a preliminary line for
3368 failures, but not defers. However, always log it for defer, and log it for fail
3369 unless the sender_verify_fail log selector has been turned off. */
3371 if (sender_verified_failed &&
3372 !testflag(sender_verified_failed, af_sverify_told))
3374 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3375 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3377 setflag(sender_verified_failed, af_sverify_told);
3379 if (rc != FAIL || LOGGING(sender_verify_fail))
3380 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3381 host_and_ident(TRUE),
3382 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3383 sender_verified_failed->address,
3384 (sender_verified_failed->message == NULL)? US"" :
3385 string_sprintf(": %s", sender_verified_failed->message));
3387 if (rc == FAIL && sender_verified_failed->user_message)
3388 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3389 testflag(sender_verified_failed, af_verify_pmfail)?
3390 "Postmaster verification failed while checking <%s>\n%s\n"
3391 "Several RFCs state that you are required to have a postmaster\n"
3392 "mailbox for each mail domain. This host does not accept mail\n"
3393 "from domains whose servers reject the postmaster address."
3395 testflag(sender_verified_failed, af_verify_nsfail)?
3396 "Callback setup failed while verifying <%s>\n%s\n"
3397 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3398 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3399 "RFC requirements, and stops you from receiving standard bounce\n"
3400 "messages. This host does not accept mail from domains whose servers\n"
3403 "Verification failed for <%s>\n%s",
3404 sender_verified_failed->address,
3405 sender_verified_failed->user_message));
3407 fl.rcpt_in_progress = save_rcpt_in_progress;
3410 /* Sort out text for logging */
3412 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3413 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3415 /* Send permanent failure response to the command, but the code used isn't
3416 always a 5xx one - see comments at the start of this function. If the original
3417 rc was FAIL_DROP we drop the connection and yield 2. */
3420 smtp_respond(smtp_code, codelen, TRUE,
3421 user_msg ? user_msg : US"Administrative prohibition");
3423 /* Send temporary failure response to the command. Don't give any details,
3424 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3425 verb, and for a header verify when smtp_return_error_details is set.
3427 This conditional logic is all somewhat of a mess because of the odd
3428 interactions between temp_details and return_error_details. One day it should
3429 be re-implemented in a tidier fashion. */
3432 if (f.acl_temp_details && user_msg)
3434 if ( smtp_return_error_details
3435 && sender_verified_failed
3436 && sender_verified_failed->message
3438 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3440 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3443 smtp_respond(smtp_code, codelen, TRUE,
3444 US"Temporary local problem - please try later");
3446 /* Log the incident to the logs that are specified by log_reject_target
3447 (default main, reject). This can be empty to suppress logging of rejections. If
3448 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3449 is closing if required and return 2. */
3451 if (log_reject_target != 0)
3454 gstring * g = s_tlslog(NULL);
3455 uschar * tls = string_from_gstring(g);
3456 if (!tls) tls = US"";
3458 uschar * tls = US"";
3460 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3461 log_reject_target, "%s%s%s %s%srejected %s%s",
3462 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3463 host_and_ident(TRUE),
3466 rc == FAIL ? US"" : US"temporarily ",
3470 if (!drop) return 0;
3472 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3473 smtp_get_connection_info());
3475 /* Run the not-quit ACL, but without any custom messages. This should not be a
3476 problem, because we get here only if some other ACL has issued "drop", and
3477 in that case, *its* custom messages will have been used above. */
3479 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3486 /*************************************************
3487 * Handle SMTP exit when QUIT is not given *
3488 *************************************************/
3490 /* This function provides a logging/statistics hook for when an SMTP connection
3491 is dropped on the floor or the other end goes away. It's a global function
3492 because it's called from receive.c as well as this module. As well as running
3493 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3494 response, either with a custom message from the ACL, or using a default. There
3495 is one case, however, when no message is output - after "drop". In that case,
3496 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3497 passed to this function.
3499 In case things go wrong while processing this function, causing an error that
3500 may re-enter this function, there is a recursion check.
3503 reason What $smtp_notquit_reason will be set to in the ACL;
3504 if NULL, the ACL is not run
3505 code The error code to return as part of the response
3506 defaultrespond The default message if there's no user_msg
3512 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3515 uschar *user_msg = NULL;
3516 uschar *log_msg = NULL;
3518 /* Check for recursive call */
3520 if (fl.smtp_exit_function_called)
3522 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3526 fl.smtp_exit_function_called = TRUE;
3528 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3530 if (acl_smtp_notquit && reason)
3532 smtp_notquit_reason = reason;
3533 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3534 &log_msg)) == ERROR)
3535 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3539 /* If the connection was dropped, we certainly are no longer talking TLS */
3540 tls_in.active.sock = -1;
3542 /* Write an SMTP response if we are expected to give one. As the default
3543 responses are all internal, they should be reasonable size. */
3545 if (code && defaultrespond)
3548 smtp_respond(code, 3, TRUE, user_msg);
3554 va_start(ap, defaultrespond);
3555 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3557 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3566 /*************************************************
3567 * Verify HELO argument *
3568 *************************************************/
3570 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3571 matched. It is also called from ACL processing if verify = helo is used and
3572 verification was not previously tried (i.e. helo_try_verify_hosts was not
3573 matched). The result of its processing is to set helo_verified and
3574 helo_verify_failed. These variables should both be FALSE for this function to
3577 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3578 for IPv6 ::ffff: literals.
3581 Returns: TRUE if testing was completed;
3582 FALSE on a temporary failure
3586 smtp_verify_helo(void)
3590 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3593 if (sender_helo_name == NULL)
3595 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3598 /* Deal with the case of -bs without an IP address */
3600 else if (sender_host_address == NULL)
3602 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3603 f.helo_verified = TRUE;
3606 /* Deal with the more common case when there is a sending IP address */
3608 else if (sender_helo_name[0] == '[')
3610 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3611 Ustrlen(sender_host_address)) == 0;
3614 if (!f.helo_verified)
3616 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3617 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3618 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3623 { if (f.helo_verified) debug_printf("matched host address\n"); }
3626 /* Do a reverse lookup if one hasn't already given a positive or negative
3627 response. If that fails, or the name doesn't match, try checking with a forward
3632 if (sender_host_name == NULL && !host_lookup_failed)
3633 yield = host_name_lookup() != DEFER;
3635 /* If a host name is known, check it and all its aliases. */
3637 if (sender_host_name)
3638 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3640 sender_helo_dnssec = sender_host_dnssec;
3641 HDEBUG(D_receive) debug_printf("matched host name\n");
3645 uschar **aliases = sender_host_aliases;
3647 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3649 sender_helo_dnssec = sender_host_dnssec;
3653 HDEBUG(D_receive) if (f.helo_verified)
3654 debug_printf("matched alias %s\n", *(--aliases));
3657 /* Final attempt: try a forward lookup of the helo name */
3659 if (!f.helo_verified)
3663 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3665 {.request = US"*", .require = US""};
3667 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3669 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3670 NULL, NULL, NULL, &d, NULL, NULL);
3671 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3672 for (host_item * hh = &h; hh; hh = hh->next)
3673 if (Ustrcmp(hh->address, sender_host_address) == 0)
3675 f.helo_verified = TRUE;
3676 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3678 debug_printf("IP address for %s matches calling address\n"
3679 "Forward DNS security status: %sverified\n",
3680 sender_helo_name, sender_helo_dnssec ? "" : "un");
3686 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3693 /*************************************************
3694 * Send user response message *
3695 *************************************************/
3697 /* This function is passed a default response code and a user message. It calls
3698 smtp_message_code() to check and possibly modify the response code, and then
3699 calls smtp_respond() to transmit the response. I put this into a function
3700 just to avoid a lot of repetition.
3703 code the response code
3704 user_msg the user message
3710 smtp_user_msg(uschar *code, uschar *user_msg)
3713 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3714 smtp_respond(code, len, TRUE, user_msg);
3720 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3722 const uschar *set_id = NULL;
3725 /* Run the checking code, passing the remainder of the command line as
3726 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3727 it as the only set numerical variable. The authenticator may set $auth<n>
3728 and also set other numeric variables. The $auth<n> variables are preferred
3729 nowadays; the numerical variables remain for backwards compatibility.
3731 Afterwards, have a go at expanding the set_id string, even if
3732 authentication failed - for bad passwords it can be useful to log the
3733 userid. On success, require set_id to expand and exist, and put it in
3734 authenticated_id. Save this in permanent store, as the working store gets
3735 reset at HELO, RSET, etc. */
3737 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3739 expand_nlength[0] = 0; /* $0 contains nothing */
3741 rc = (au->info->servercode)(au, smtp_cmd_data);
3742 if (au->set_id) set_id = expand_string(au->set_id);
3743 expand_nmax = -1; /* Reset numeric variables */
3744 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3746 /* The value of authenticated_id is stored in the spool file and printed in
3747 log lines. It must not contain binary zeros or newline characters. In
3748 normal use, it never will, but when playing around or testing, this error
3749 can (did) happen. To guard against this, ensure that the id contains only
3750 printing characters. */
3752 if (set_id) set_id = string_printing(set_id);
3754 /* For the non-OK cases, set up additional logging data if set_id
3758 set_id = set_id && *set_id
3759 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3761 /* Switch on the result */
3766 if (!au->set_id || set_id) /* Complete success */
3768 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3769 sender_host_authenticated = au->name;
3770 sender_host_auth_pubname = au->public_name;
3771 authentication_failed = FALSE;
3772 authenticated_fail_id = NULL; /* Impossible to already be set? */
3775 (sender_host_address ? protocols : protocols_local)
3776 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3777 *s = *ss = US"235 Authentication succeeded";
3778 authenticated_by = au;
3782 /* Authentication succeeded, but we failed to expand the set_id string.
3783 Treat this as a temporary error. */
3785 auth_defer_msg = expand_string_message;
3789 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3790 *s = string_sprintf("435 Unable to authenticate at present%s",
3791 auth_defer_user_msg);
3792 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3793 set_id, auth_defer_msg);
3797 *s = *ss = US"501 Invalid base64 data";
3801 *s = *ss = US"501 Authentication cancelled";
3805 *s = *ss = US"553 Initial data not expected";
3809 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3810 *s = US"535 Incorrect authentication data";
3811 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3815 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3816 *s = US"435 Internal error";
3817 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3818 "check", set_id, rc);
3830 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3833 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3835 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3837 rd = Ustrlen(recipient) + 1;
3838 *recipient = rewrite_address_qualify(*recipient, TRUE);
3841 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3843 log_write(L_smtp_syntax_error,
3844 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3845 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3853 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3856 incomplete_transaction_log(US"QUIT");
3859 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3861 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3866 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3870 smtp_respond(US"221", 3, TRUE, *user_msgp);
3872 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3875 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3878 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3879 smtp_get_connection_info());
3884 smtp_rset_handler(void)
3887 incomplete_transaction_log(US"RSET");
3888 smtp_printf("250 Reset OK\r\n", FALSE);
3889 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3894 /*************************************************
3895 * Initialize for SMTP incoming message *
3896 *************************************************/
3898 /* This function conducts the initial dialogue at the start of an incoming SMTP
3899 message, and builds a list of recipients. However, if the incoming message
3900 is part of a batch (-bS option) a separate function is called since it would
3901 be messy having tests splattered about all over this function. This function
3902 therefore handles the case where interaction is occurring. The input and output
3903 files are set up in smtp_in and smtp_out.
3905 The global recipients_list is set to point to a vector of recipient_item
3906 blocks, whose number is given by recipients_count. This is extended by the
3907 receive_add_recipient() function. The global variable sender_address is set to
3908 the sender's address. The yield is +1 if a message has been successfully
3909 started, 0 if a QUIT command was encountered or the connection was refused from
3910 the particular host, or -1 if the connection was lost.
3914 Returns: > 0 message successfully started (reached DATA)
3915 = 0 QUIT read or end of file reached or call refused
3920 smtp_setup_msg(void)
3923 BOOL toomany = FALSE;
3924 BOOL discarded = FALSE;
3925 BOOL last_was_rej_mail = FALSE;
3926 BOOL last_was_rcpt = FALSE;
3927 rmark reset_point = store_mark();
3929 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3931 /* Reset for start of new message. We allow one RSET not to be counted as a
3932 nonmail command, for those MTAs that insist on sending it between every
3933 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3934 TLS between messages (an Exim client may do this if it has messages queued up
3935 for the host). Note: we do NOT reset AUTH at this point. */
3937 reset_point = smtp_reset(reset_point);
3938 message_ended = END_NOTSTARTED;
3940 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3942 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3943 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3944 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3946 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3949 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3951 had_command_sigterm = 0;
3952 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3954 /* Batched SMTP is handled in a different function. */
3956 if (smtp_batched_input) return smtp_setup_batch_msg();
3958 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3959 value. The values are 2 larger than the required yield of the function. */
3963 const uschar **argv;
3964 uschar *etrn_command;
3965 uschar *etrn_serialize_key;
3967 uschar *log_msg, *smtp_code;
3968 uschar *user_msg = NULL;
3969 uschar *recipient = NULL;
3970 uschar *hello = NULL;
3972 BOOL was_rej_mail = FALSE;
3973 BOOL was_rcpt = FALSE;
3974 void (*oldsignal)(int);
3976 int start, end, sender_domain, recipient_domain;
3979 uschar *orcpt = NULL;
3984 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3985 if ( tls_in.active.sock >= 0
3987 && tls_in.certificate_verified
3988 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3991 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3993 for (auth_instance * au = auths; au; au = au->next)
3994 if (strcmpic(US"tls", au->driver_name) == 0)
3997 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3998 &user_msg, &log_msg)) != OK
4000 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4003 smtp_cmd_data = NULL;
4005 if (smtp_in_auth(au, &s, &ss) == OK)
4006 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4008 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4016 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4017 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4018 US &off, sizeof(off));
4021 switch(smtp_read_command(
4022 #ifndef DISABLE_PIPE_CONNECT
4023 !fl.pipe_connect_acceptable,
4027 GETC_BUFFER_UNLIMITED))
4029 /* The AUTH command is not permitted to occur inside a transaction, and may
4030 occur successfully only once per connection. Actually, that isn't quite
4031 true. When TLS is started, all previous information about a connection must
4032 be discarded, so a new AUTH is permitted at that time.
4034 AUTH may only be used when it has been advertised. However, it seems that
4035 there are clients that send AUTH when it hasn't been advertised, some of
4036 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4037 So there's a get-out that allows this to happen.
4039 AUTH is initially labelled as a "nonmail command" so that one occurrence
4040 doesn't get counted. We change the label here so that multiple failing
4041 AUTHS will eventually hit the nonmail threshold. */
4045 authentication_failed = TRUE;
4046 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4048 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4050 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4051 US"AUTH command used when not advertised");
4054 if (sender_host_authenticated)
4056 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4057 US"already authenticated");
4062 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4063 US"not permitted in mail transaction");
4070 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4071 &user_msg, &log_msg)) != OK
4074 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4078 /* Find the name of the requested authentication mechanism. */
4081 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4083 if (!isalnum(c) && c != '-' && c != '_')
4085 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4086 US"invalid character in authentication mechanism name");
4092 /* If not at the end of the line, we must be at white space. Terminate the
4093 name and move the pointer on to any data that may be present. */
4095 if (*smtp_cmd_data != 0)
4097 *smtp_cmd_data++ = 0;
4098 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4101 /* Search for an authentication mechanism which is configured for use
4102 as a server and which has been advertised (unless, sigh, allow_auth_
4103 unadvertised is set). */
4107 for (au = auths; au; au = au->next)
4108 if (strcmpic(s, au->public_name) == 0 && au->server &&
4109 (au->advertised || f.allow_auth_unadvertised))
4114 c = smtp_in_auth(au, &s, &ss);
4116 smtp_printf("%s\r\n", FALSE, s);
4118 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4119 au->name, host_and_ident(FALSE), ss);
4122 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4123 string_sprintf("%s authentication mechanism not supported", s));
4126 break; /* AUTH_CMD */
4128 /* The HELO/EHLO commands are permitted to appear in the middle of a
4129 session as well as at the beginning. They have the effect of a reset in
4130 addition to their other functions. Their absence at the start cannot be
4131 taken to be an error.
4135 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4136 or 502 failure replies MUST be returned as appropriate. The SMTP
4137 server MUST stay in the same state after transmitting these replies
4138 that it was in before the EHLO was received.
4140 Therefore, we do not do the reset until after checking the command for
4141 acceptability. This change was made for Exim release 4.11. Previously
4142 it did the reset first. */
4155 HELO_EHLO: /* Common code for HELO and EHLO */
4156 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4157 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4159 /* Reject the HELO if its argument was invalid or non-existent. A
4160 successful check causes the argument to be saved in malloc store. */
4162 if (!check_helo(smtp_cmd_data))
4164 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4166 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4167 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4168 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4169 string_printing(smtp_cmd_argument));
4171 if (++synprot_error_count > smtp_max_synprot_errors)
4173 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4174 "syntax or protocol errors (last command was \"%s\", %s)",
4175 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4176 string_from_gstring(s_connhad_log(NULL))
4184 /* If sender_host_unknown is true, we have got here via the -bs interface,
4185 not called from inetd. Otherwise, we are running an IP connection and the
4186 host address will be set. If the helo name is the primary name of this
4187 host and we haven't done a reverse lookup, force one now. If helo_required
4188 is set, ensure that the HELO name matches the actual host. If helo_verify
4189 is set, do the same check, but softly. */
4191 if (!f.sender_host_unknown)
4193 BOOL old_helo_verified = f.helo_verified;
4194 uschar *p = smtp_cmd_data;
4196 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4199 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4200 because otherwise the log can be confusing. */
4202 if ( !sender_host_name
4203 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4204 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4205 (void)host_name_lookup();
4207 /* Rebuild the fullhost info to include the HELO name (and the real name
4208 if it was looked up.) */
4210 host_build_sender_fullhost(); /* Rebuild */
4211 set_process_info("handling%s incoming connection from %s",
4212 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4214 /* Verify if configured. This doesn't give much security, but it does
4215 make some people happy to be able to do it. If helo_required is set,
4216 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4217 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4218 now obsolescent, since the verification can now be requested selectively
4221 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4222 if (fl.helo_required || fl.helo_verify)
4224 BOOL tempfail = !smtp_verify_helo();
4225 if (!f.helo_verified)
4227 if (fl.helo_required)
4229 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4230 tempfail? 451 : 550, hello);
4231 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4232 tempfail? "temporarily " : "",
4233 hello, sender_helo_name, host_and_ident(FALSE));
4234 f.helo_verified = old_helo_verified;
4235 break; /* End of HELO/EHLO processing */
4237 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4238 "helo_try_verify_hosts\n", hello);
4244 /* set up SPF context */
4245 spf_conn_init(sender_helo_name, sender_host_address);
4248 /* Apply an ACL check if one is defined; afterwards, recheck
4249 synchronization in case the client started sending in a delay. */
4252 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4253 &user_msg, &log_msg)) != OK)
4255 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4256 sender_helo_name = NULL;
4257 host_build_sender_fullhost(); /* Rebuild */
4260 #ifndef DISABLE_PIPE_CONNECT
4261 else if (!fl.pipe_connect_acceptable && !check_sync())
4263 else if (!check_sync())
4267 /* Generate an OK reply. The default string includes the ident if present,
4268 and also the IP address if present. Reflecting back the ident is intended
4269 as a deterrent to mail forgers. For maximum efficiency, and also because
4270 some broken systems expect each response to be in a single packet, arrange
4271 that the entire reply is sent in one write(). */
4273 fl.auth_advertised = FALSE;
4274 f.smtp_in_pipelining_advertised = FALSE;
4276 fl.tls_advertised = FALSE;
4278 fl.dsn_advertised = FALSE;
4280 fl.smtputf8_advertised = FALSE;
4283 smtp_code = US"250 "; /* Default response code plus space*/
4286 /* sender_host_name below will be tainted, so save on copy when we hit it */
4287 g = string_get_tainted(24, TRUE);
4288 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4290 smtp_active_hostname,
4291 sender_ident ? sender_ident : US"",
4292 sender_ident ? US" at " : US"",
4293 sender_host_name ? sender_host_name : sender_helo_name);
4295 if (sender_host_address)
4296 g = string_fmt_append(g, " [%s]", sender_host_address);
4299 /* A user-supplied EHLO greeting may not contain more than one line. Note
4300 that the code returned by smtp_message_code() includes the terminating
4301 whitespace character. */
4307 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4308 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4309 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4311 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4312 "newlines: message truncated: %s", string_printing(s));
4315 g = string_cat(NULL, s);
4318 g = string_catn(g, US"\r\n", 2);
4320 /* If we received EHLO, we must create a multiline response which includes
4321 the functions supported. */
4327 /* I'm not entirely happy with this, as an MTA is supposed to check
4328 that it has enough room to accept a message of maximum size before
4329 it sends this. However, there seems little point in not sending it.
4330 The actual size check happens later at MAIL FROM time. By postponing it
4331 till then, VRFY and EXPN can be used after EHLO when space is short. */
4333 if (thismessage_size_limit > 0)
4334 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4335 thismessage_size_limit);
4338 g = string_catn(g, smtp_code, 3);
4339 g = string_catn(g, US"-SIZE\r\n", 7);
4342 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4343 clean; if it has an 8-bit character in its hand, it just sends it. It
4344 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4345 However, some users want this option simply in order to stop MUAs
4346 mangling messages that contain top-bit-set characters. It is therefore
4347 provided as an option. */
4349 if (accept_8bitmime)
4351 g = string_catn(g, smtp_code, 3);
4352 g = string_catn(g, US"-8BITMIME\r\n", 11);
4355 /* Advertise DSN support if configured to do so. */
4356 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4358 g = string_catn(g, smtp_code, 3);
4359 g = string_catn(g, US"-DSN\r\n", 6);
4360 fl.dsn_advertised = TRUE;
4363 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4364 permitted to issue them; a check is made when any host actually tries. */
4368 g = string_catn(g, smtp_code, 3);
4369 g = string_catn(g, US"-ETRN\r\n", 7);
4373 g = string_catn(g, smtp_code, 3);
4374 g = string_catn(g, US"-VRFY\r\n", 7);
4378 g = string_catn(g, smtp_code, 3);
4379 g = string_catn(g, US"-EXPN\r\n", 7);
4382 /* Exim is quite happy with pipelining, so let the other end know that
4383 it is safe to use it, unless advertising is disabled. */
4385 if ( f.pipelining_enable
4386 && verify_check_host(&pipelining_advertise_hosts) == OK)
4388 g = string_catn(g, smtp_code, 3);
4389 g = string_catn(g, US"-PIPELINING\r\n", 13);
4390 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4391 f.smtp_in_pipelining_advertised = TRUE;
4393 #ifndef DISABLE_PIPE_CONNECT
4394 if (fl.pipe_connect_acceptable)
4396 f.smtp_in_early_pipe_advertised = TRUE;
4397 g = string_catn(g, smtp_code, 3);
4398 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4404 /* If any server authentication mechanisms are configured, advertise
4405 them if the current host is in auth_advertise_hosts. The problem with
4406 advertising always is that some clients then require users to
4407 authenticate (and aren't configurable otherwise) even though it may not
4408 be necessary (e.g. if the host is in host_accept_relay).
4410 RFC 2222 states that SASL mechanism names contain only upper case
4411 letters, so output the names in upper case, though we actually recognize
4412 them in either case in the AUTH command. */
4416 && !sender_host_authenticated
4418 && verify_check_host(&auth_advertise_hosts) == OK
4422 for (auth_instance * au = auths; au; au = au->next)
4424 au->advertised = FALSE;
4427 DEBUG(D_auth+D_expand) debug_printf_indent(
4428 "Evaluating advertise_condition for %s %s athenticator\n",
4429 au->name, au->public_name);
4430 if ( !au->advertise_condition
4431 || expand_check_condition(au->advertise_condition, au->name,
4438 g = string_catn(g, smtp_code, 3);
4439 g = string_catn(g, US"-AUTH", 5);
4441 fl.auth_advertised = TRUE;
4444 g = string_catn(g, US" ", 1);
4445 g = string_cat (g, au->public_name);
4446 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4447 au->advertised = TRUE;
4452 if (!first) g = string_catn(g, US"\r\n", 2);
4455 /* RFC 3030 CHUNKING */
4457 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4459 g = string_catn(g, smtp_code, 3);
4460 g = string_catn(g, US"-CHUNKING\r\n", 11);
4461 f.chunking_offered = TRUE;
4462 chunking_state = CHUNKING_OFFERED;
4465 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4466 if it has been included in the binary, and the host matches
4467 tls_advertise_hosts. We must *not* advertise if we are already in a
4468 secure connection. */
4471 if (tls_in.active.sock < 0 &&
4472 verify_check_host(&tls_advertise_hosts) != FAIL)
4474 g = string_catn(g, smtp_code, 3);
4475 g = string_catn(g, US"-STARTTLS\r\n", 11);
4476 fl.tls_advertised = TRUE;
4480 #ifndef DISABLE_PRDR
4481 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4484 g = string_catn(g, smtp_code, 3);
4485 g = string_catn(g, US"-PRDR\r\n", 7);
4490 if ( accept_8bitmime
4491 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4493 g = string_catn(g, smtp_code, 3);
4494 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4495 fl.smtputf8_advertised = TRUE;
4499 /* Finish off the multiline reply with one that is always available. */
4501 g = string_catn(g, smtp_code, 3);
4502 g = string_catn(g, US" HELP\r\n", 7);
4505 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4509 if (tls_in.active.sock >= 0)
4510 (void)tls_write(NULL, g->s, g->ptr,
4511 # ifndef DISABLE_PIPE_CONNECT
4512 fl.pipe_connect_acceptable && pipeline_connect_sends());
4520 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4526 (void) string_from_gstring(g);
4527 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4528 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4529 debug_printf("SMTP>> %s", g->s);
4531 fl.helo_seen = TRUE;
4533 /* Reset the protocol and the state, abandoning any previous message. */
4535 (sender_host_address ? protocols : protocols_local)
4537 ? pextend + (sender_host_authenticated ? pauthed : 0)
4539 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4541 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4542 reset_point = smtp_reset(reset_point);
4544 break; /* HELO/EHLO */
4547 /* The MAIL command requires an address as an operand. All we do
4548 here is to parse it for syntactic correctness. The form "<>" is
4549 a special case which converts into an empty string. The start/end
4550 pointers in the original are not used further for this address, as
4551 it is the canonical extracted address which is all that is kept. */
4555 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4556 was_rej_mail = TRUE; /* Reset if accepted */
4557 env_mail_type_t * mail_args; /* Sanity check & validate args */
4559 if (fl.helo_required && !fl.helo_seen)
4561 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4562 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4563 "HELO/EHLO given", host_and_ident(FALSE));
4569 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4570 US"sender already given");
4574 if (!*smtp_cmd_data)
4576 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4577 US"MAIL must have an address operand");
4581 /* Check to see if the limit for messages per connection would be
4582 exceeded by accepting further messages. */
4584 if (smtp_accept_max_per_connection > 0 &&
4585 smtp_mailcmd_count > smtp_accept_max_per_connection)
4587 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4588 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4589 "messages in one connection", host_and_ident(TRUE));
4593 /* Reset for start of message - even if this is going to fail, we
4594 obviously need to throw away any previous data. */
4596 cancel_cutthrough_connection(TRUE, US"MAIL received");
4597 reset_point = smtp_reset(reset_point);
4599 sender_data = recipient_data = NULL;
4601 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4603 if (fl.esmtp) for(;;)
4605 uschar *name, *value, *end;
4606 unsigned long int size;
4607 BOOL arg_error = FALSE;
4609 if (!extract_option(&name, &value)) break;
4611 for (mail_args = env_mail_type_list;
4612 mail_args->value != ENV_MAIL_OPT_NULL;
4615 if (strcmpic(name, mail_args->name) == 0)
4617 if (mail_args->need_value && strcmpic(value, US"") == 0)
4620 switch(mail_args->value)
4622 /* Handle SIZE= by reading the value. We don't do the check till later,
4623 in order to be able to log the sender address on failure. */
4624 case ENV_MAIL_OPT_SIZE:
4625 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4627 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4629 message_size = (int)size;
4635 /* If this session was initiated with EHLO and accept_8bitmime is set,
4636 Exim will have indicated that it supports the BODY=8BITMIME option. In
4637 fact, it does not support this according to the RFCs, in that it does not
4638 take any special action for forwarding messages containing 8-bit
4639 characters. That is why accept_8bitmime is not the default setting, but
4640 some sites want the action that is provided. We recognize both "8BITMIME"
4641 and "7BIT" as body types, but take no action. */
4642 case ENV_MAIL_OPT_BODY:
4643 if (accept_8bitmime) {
4644 if (strcmpic(value, US"8BITMIME") == 0)
4646 else if (strcmpic(value, US"7BIT") == 0)
4651 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4652 US"invalid data for BODY");
4655 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4661 /* Handle the two DSN options, but only if configured to do so (which
4662 will have caused "DSN" to be given in the EHLO response). The code itself
4663 is included only if configured in at build time. */
4665 case ENV_MAIL_OPT_RET:
4666 if (fl.dsn_advertised)
4668 /* Check if RET has already been set */
4671 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4672 US"RET can be specified once only");
4675 dsn_ret = strcmpic(value, US"HDRS") == 0
4677 : strcmpic(value, US"FULL") == 0
4680 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4681 /* Check for invalid invalid value, and exit with error */
4684 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4685 US"Value for RET is invalid");
4690 case ENV_MAIL_OPT_ENVID:
4691 if (fl.dsn_advertised)
4693 /* Check if the dsn envid has been already set */
4696 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4697 US"ENVID can be specified once only");
4700 dsn_envid = string_copy(value);
4701 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4705 /* Handle the AUTH extension. If the value given is not "<>" and either
4706 the ACL says "yes" or there is no ACL but the sending host is
4707 authenticated, we set it up as the authenticated sender. However, if the
4708 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4709 the condition is met. The value of AUTH is an xtext, which means that +,
4710 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4712 case ENV_MAIL_OPT_AUTH:
4713 if (Ustrcmp(value, "<>") != 0)
4718 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4720 /* Put back terminator overrides for error message */
4723 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4724 US"invalid data for AUTH");
4727 if (!acl_smtp_mailauth)
4729 ignore_msg = US"client not authenticated";
4730 rc = sender_host_authenticated ? OK : FAIL;
4734 ignore_msg = US"rejected by ACL";
4735 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4736 &user_msg, &log_msg);
4742 if (authenticated_by == NULL ||
4743 authenticated_by->mail_auth_condition == NULL ||
4744 expand_check_condition(authenticated_by->mail_auth_condition,
4745 authenticated_by->name, US"authenticator"))
4746 break; /* Accept the AUTH */
4748 ignore_msg = US"server_mail_auth_condition failed";
4749 if (authenticated_id != NULL)
4750 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4751 ignore_msg, authenticated_id);
4756 authenticated_sender = NULL;
4757 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4758 value, host_and_ident(TRUE), ignore_msg);
4761 /* Should only get DEFER or ERROR here. Put back terminator
4762 overrides for error message */
4767 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4774 #ifndef DISABLE_PRDR
4775 case ENV_MAIL_OPT_PRDR:
4777 prdr_requested = TRUE;
4782 case ENV_MAIL_OPT_UTF8:
4783 if (!fl.smtputf8_advertised)
4785 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4786 US"SMTPUTF8 used when not advertised");
4790 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4791 message_smtputf8 = allow_utf8_domains = TRUE;
4792 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4794 int old_pool = store_pool;
4795 store_pool = POOL_PERM;
4796 received_protocol = string_sprintf("utf8%s", received_protocol);
4797 store_pool = old_pool;
4802 /* No valid option. Stick back the terminator characters and break
4803 the loop. Do the name-terminator second as extract_option sets
4804 value==name when it found no equal-sign.
4805 An error for a malformed address will occur. */
4806 case ENV_MAIL_OPT_NULL:
4814 /* Break out of for loop if switch() had bad argument or
4815 when start of the email address is reached */
4816 if (arg_error) break;
4819 /* If we have passed the threshold for rate limiting, apply the current
4820 delay, and update it for next time, provided this is a limited host. */
4822 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4823 verify_check_host(&smtp_ratelimit_hosts) == OK)
4825 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4826 smtp_delay_mail/1000.0);
4827 millisleep((int)smtp_delay_mail);
4828 smtp_delay_mail *= smtp_rlm_factor;
4829 if (smtp_delay_mail > (double)smtp_rlm_limit)
4830 smtp_delay_mail = (double)smtp_rlm_limit;
4833 /* Now extract the address, first applying any SMTP-time rewriting. The
4834 TRUE flag allows "<>" as a sender address. */
4836 raw_sender = rewrite_existflags & rewrite_smtp
4837 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4838 global_rewrite_rules)
4842 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4847 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4851 sender_address = raw_sender;
4853 /* If there is a configured size limit for mail, check that this message
4854 doesn't exceed it. The check is postponed to this point so that the sender
4857 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4859 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4860 log_write(L_size_reject,
4861 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4862 "message too big: size%s=%d max=%d",
4864 host_and_ident(TRUE),
4865 (message_size == INT_MAX)? ">" : "",
4867 thismessage_size_limit);
4868 sender_address = NULL;
4872 /* Check there is enough space on the disk unless configured not to.
4873 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4874 plus the current message - i.e. we accept the message only if it won't
4875 reduce the space below the threshold. Add 5000 to the size to allow for
4876 overheads such as the Received: line and storing of recipients, etc.
4877 By putting the check here, even when SIZE is not given, it allow VRFY
4878 and EXPN etc. to be used when space is short. */
4880 if (!receive_check_fs(
4881 smtp_check_spool_space && message_size >= 0
4882 ? message_size + 5000 : 0))
4884 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4885 sender_address = NULL;
4889 /* If sender_address is unqualified, reject it, unless this is a locally
4890 generated message, or the sending host or net is permitted to send
4891 unqualified addresses - typically local machines behaving as MUAs -
4892 in which case just qualify the address. The flag is set above at the start
4893 of the SMTP connection. */
4895 if (!sender_domain && *sender_address)
4896 if (f.allow_unqualified_sender)
4898 sender_domain = Ustrlen(sender_address) + 1;
4899 sender_address = rewrite_address_qualify(sender_address, FALSE);
4900 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4905 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4907 log_write(L_smtp_syntax_error,
4908 LOG_MAIN|LOG_REJECT,
4909 "unqualified sender rejected: <%s> %s%s",
4911 host_and_ident(TRUE),
4913 sender_address = NULL;
4917 /* Apply an ACL check if one is defined, before responding. Afterwards,
4918 when pipelining is not advertised, do another sync check in case the ACL
4919 delayed and the client started sending in the meantime. */
4923 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4924 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4930 if (rc == OK || rc == DISCARD)
4932 BOOL more = pipeline_response();
4935 smtp_printf("%s%s%s", more, US"250 OK",
4936 #ifndef DISABLE_PRDR
4937 prdr_requested ? US", PRDR Requested" : US"",
4944 #ifndef DISABLE_PRDR
4946 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4948 smtp_user_msg(US"250", user_msg);
4950 smtp_delay_rcpt = smtp_rlr_base;
4951 f.recipients_discarded = (rc == DISCARD);
4952 was_rej_mail = FALSE;
4956 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4957 sender_address = NULL;
4962 /* The RCPT command requires an address as an operand. There may be any
4963 number of RCPT commands, specifying multiple recipients. We build them all
4964 into a data structure. The start/end values given by parse_extract_address
4965 are not used, as we keep only the extracted address. */
4970 was_rcpt = fl.rcpt_in_progress = TRUE;
4972 /* There must be a sender address; if the sender was rejected and
4973 pipelining was advertised, we assume the client was pipelining, and do not
4974 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4975 get the same treatment. */
4977 if (sender_address == NULL)
4979 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4981 smtp_printf("503 sender not yet given\r\n", FALSE);
4982 was_rej_mail = TRUE;
4986 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4987 US"sender not yet given");
4988 was_rcpt = FALSE; /* Not a valid RCPT */
4994 /* Check for an operand */
4996 if (smtp_cmd_data[0] == 0)
4998 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4999 US"RCPT must have an address operand");
5004 /* Set the DSN flags orcpt and dsn_flags from the session*/
5008 if (fl.esmtp) for(;;)
5010 uschar *name, *value;
5012 if (!extract_option(&name, &value))
5015 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5017 /* Check whether orcpt has been already set */
5020 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5021 US"ORCPT can be specified once only");
5024 orcpt = string_copy(value);
5025 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5028 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5030 /* Check if the notify flags have been already set */
5033 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5034 US"NOTIFY can be specified once only");
5037 if (strcmpic(value, US"NEVER") == 0)
5038 dsn_flags |= rf_notify_never;
5045 while (*pp != 0 && *pp != ',') pp++;
5046 if (*pp == ',') *pp++ = 0;
5047 if (strcmpic(p, US"SUCCESS") == 0)
5049 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5050 dsn_flags |= rf_notify_success;
5052 else if (strcmpic(p, US"FAILURE") == 0)
5054 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5055 dsn_flags |= rf_notify_failure;
5057 else if (strcmpic(p, US"DELAY") == 0)
5059 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5060 dsn_flags |= rf_notify_delay;
5064 /* Catch any strange values */
5065 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5066 US"Invalid value for NOTIFY parameter");
5071 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5075 /* Unknown option. Stick back the terminator characters and break
5076 the loop. An error for a malformed address will occur. */
5080 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5087 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5088 as a recipient address */
5090 recipient = rewrite_existflags & rewrite_smtp
5091 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5092 global_rewrite_rules)
5095 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5096 &recipient_domain, FALSE)))
5098 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5103 /* If the recipient address is unqualified, reject it, unless this is a
5104 locally generated message. However, unqualified addresses are permitted
5105 from a configured list of hosts and nets - typically when behaving as
5106 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5107 really. The flag is set at the start of the SMTP connection.
5109 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5110 assumed this meant "reserved local part", but the revision of RFC 821 and
5111 friends now makes it absolutely clear that it means *mailbox*. Consequently
5112 we must always qualify this address, regardless. */
5114 if (!recipient_domain)
5115 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5122 /* Check maximum allowed */
5124 if (rcpt_count > recipients_max && recipients_max > 0)
5126 if (recipients_max_reject)
5129 smtp_printf("552 too many recipients\r\n", FALSE);
5131 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5132 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5137 smtp_printf("452 too many recipients\r\n", FALSE);
5139 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5140 "temporarily rejected: sender=<%s> %s", sender_address,
5141 host_and_ident(TRUE));
5148 /* If we have passed the threshold for rate limiting, apply the current
5149 delay, and update it for next time, provided this is a limited host. */
5151 if (rcpt_count > smtp_rlr_threshold &&
5152 verify_check_host(&smtp_ratelimit_hosts) == OK)
5154 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5155 smtp_delay_rcpt/1000.0);
5156 millisleep((int)smtp_delay_rcpt);
5157 smtp_delay_rcpt *= smtp_rlr_factor;
5158 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5159 smtp_delay_rcpt = (double)smtp_rlr_limit;
5162 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5163 for them. Otherwise, check the access control list for this recipient. As
5164 there may be a delay in this, re-check for a synchronization error
5165 afterwards, unless pipelining was advertised. */
5167 if (f.recipients_discarded)
5170 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5172 && !f.smtp_in_pipelining_advertised && !check_sync())
5175 /* The ACL was happy */
5179 BOOL more = pipeline_response();
5182 smtp_user_msg(US"250", user_msg);
5184 smtp_printf("250 Accepted\r\n", more);
5185 receive_add_recipient(recipient, -1);
5187 /* Set the dsn flags in the recipients_list */
5188 recipients_list[recipients_count-1].orcpt = orcpt;
5189 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5191 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5192 recipients_list[recipients_count-1].orcpt,
5193 recipients_list[recipients_count-1].dsn_flags); */
5196 /* The recipient was discarded */
5198 else if (rc == DISCARD)
5201 smtp_user_msg(US"250", user_msg);
5203 smtp_printf("250 Accepted\r\n", FALSE);
5206 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5207 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5208 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5209 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5210 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5213 /* Either the ACL failed the address, or it was deferred. */
5217 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5218 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5223 /* The DATA command is legal only if it follows successful MAIL FROM
5224 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5225 not counted as a protocol error if it follows RCPT (which must have been
5226 rejected if there are no recipients.) This function is complete when a
5227 valid DATA command is encountered.
5229 Note concerning the code used: RFC 2821 says this:
5231 - If there was no MAIL, or no RCPT, command, or all such commands
5232 were rejected, the server MAY return a "command out of sequence"
5233 (503) or "no valid recipients" (554) reply in response to the
5236 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5237 because it is the same whether pipelining is in use or not.
5239 If all the RCPT commands that precede DATA provoked the same error message
5240 (often indicating some kind of system error), it is helpful to include it
5241 with the DATA rejection (an idea suggested by Tony Finch). */
5248 if (chunking_state != CHUNKING_OFFERED)
5250 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5251 US"BDAT command used when CHUNKING not advertised");
5255 /* grab size, endmarker */
5257 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5259 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5260 US"missing size for BDAT command");
5263 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5264 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5265 chunking_data_left = chunking_datasize;
5266 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5267 (int)chunking_state, chunking_data_left);
5269 /* push the current receive_* function on the "stack", and
5270 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5271 functions to do the dirty work. */
5272 lwr_receive_getc = receive_getc;
5273 lwr_receive_getbuf = receive_getbuf;
5274 lwr_receive_ungetc = receive_ungetc;
5276 receive_getc = bdat_getc;
5277 receive_ungetc = bdat_ungetc;
5288 DATA_BDAT: /* Common code for DATA and BDAT */
5289 #ifndef DISABLE_PIPE_CONNECT
5290 fl.pipe_connect_acceptable = FALSE;
5292 if (!discarded && recipients_count <= 0)
5294 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5296 uschar *code = US"503";
5297 int len = Ustrlen(rcpt_smtp_response);
5298 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5300 /* Responses from smtp_printf() will have \r\n on the end */
5301 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5302 rcpt_smtp_response[len-2] = 0;
5303 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5305 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5306 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5307 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5309 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5310 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5311 ? US"valid RCPT command must precede DATA"
5312 : US"valid RCPT command must precede BDAT");
5314 if (chunking_state > CHUNKING_OFFERED)
5319 if (toomany && recipients_max_reject)
5321 sender_address = NULL; /* This will allow a new MAIL without RSET */
5322 sender_address_unrewritten = NULL;
5323 smtp_printf("554 Too many recipients\r\n", FALSE);
5327 if (chunking_state > CHUNKING_OFFERED)
5328 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5331 /* If there is an ACL, re-check the synchronization afterwards, since the
5332 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5333 to get the DATA command sent. */
5335 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5339 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5340 f.enable_dollar_recipients = TRUE;
5341 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5343 f.enable_dollar_recipients = FALSE;
5344 if (rc == OK && !check_sync())
5348 { /* Either the ACL failed the address, or it was deferred. */
5349 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5355 smtp_user_msg(US"354", user_msg);
5358 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5362 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5363 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5364 US &on, sizeof(on));
5367 message_ended = END_NOTENDED; /* Indicate in middle of data */
5378 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5379 &start, &end, &recipient_domain, FALSE)))
5381 smtp_printf("501 %s\r\n", FALSE, errmess);
5385 if (!recipient_domain)
5386 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5390 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5391 &user_msg, &log_msg)) != OK)
5392 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5396 address_item * addr = deliver_make_addr(address, FALSE);
5398 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5399 -1, -1, NULL, NULL, NULL))
5402 s = string_sprintf("250 <%s> is deliverable", address);
5406 s = (addr->user_message != NULL)?
5407 string_sprintf("451 <%s> %s", address, addr->user_message) :
5408 string_sprintf("451 Cannot resolve <%s> at this time", address);
5412 s = (addr->user_message != NULL)?
5413 string_sprintf("550 <%s> %s", address, addr->user_message) :
5414 string_sprintf("550 <%s> is not deliverable", address);
5415 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5416 smtp_cmd_argument, host_and_ident(TRUE));
5420 smtp_printf("%s\r\n", FALSE, s);
5428 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5430 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5433 BOOL save_log_testing_mode = f.log_testing_mode;
5434 f.address_test_mode = f.log_testing_mode = TRUE;
5435 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5436 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5438 f.address_test_mode = FALSE;
5439 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5448 if (!fl.tls_advertised)
5450 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5451 US"STARTTLS command used when not advertised");
5455 /* Apply an ACL check if one is defined */
5457 if ( acl_smtp_starttls
5458 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5459 &user_msg, &log_msg)) != OK
5462 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5466 /* RFC 2487 is not clear on when this command may be sent, though it
5467 does state that all information previously obtained from the client
5468 must be discarded if a TLS session is started. It seems reasonable to
5469 do an implied RSET when STARTTLS is received. */
5471 incomplete_transaction_log(US"STARTTLS");
5472 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5473 reset_point = smtp_reset(reset_point);
5475 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5477 /* There's an attack where more data is read in past the STARTTLS command
5478 before TLS is negotiated, then assumed to be part of the secure session
5479 when used afterwards; we use segregated input buffers, so are not
5480 vulnerable, but we want to note when it happens and, for sheer paranoia,
5481 ensure that the buffer is "wiped".
5482 Pipelining sync checks will normally have protected us too, unless disabled
5483 by configuration. */
5485 if (receive_smtp_buffered())
5488 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5489 if (tls_in.active.sock < 0)
5490 smtp_inend = smtp_inptr = smtp_inbuffer;
5491 /* and if TLS is already active, tls_server_start() should fail */
5494 /* There is nothing we value in the input buffer and if TLS is successfully
5495 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5496 fresh content into it. The buffer contains arbitrary content from an
5497 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5498 It seems safest to just wipe away the content rather than leave it as a
5499 target to jump to. */
5501 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5503 /* Attempt to start up a TLS session, and if successful, discard all
5504 knowledge that was obtained previously. At least, that's what the RFC says,
5505 and that's what happens by default. However, in order to work round YAEB,
5506 there is an option to remember the esmtp state. Sigh.
5508 We must allow for an extra EHLO command and an extra AUTH command after
5509 STARTTLS that don't add to the nonmail command count. */
5512 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5514 if (!tls_remember_esmtp)
5515 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5516 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5517 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5518 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5519 if (sender_helo_name)
5521 sender_helo_name = NULL;
5522 host_build_sender_fullhost(); /* Rebuild */
5523 set_process_info("handling incoming TLS connection from %s",
5524 host_and_ident(FALSE));
5527 (sender_host_address ? protocols : protocols_local)
5529 ? pextend + (sender_host_authenticated ? pauthed : 0)
5531 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5534 sender_host_auth_pubname = sender_host_authenticated = NULL;
5535 authenticated_id = NULL;
5536 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5537 DEBUG(D_tls) debug_printf("TLS active\n");
5538 break; /* Successful STARTTLS */
5541 (void) smtp_log_tls_fail(s);
5543 /* Some local configuration problem was discovered before actually trying
5544 to do a TLS handshake; give a temporary error. */
5548 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5552 /* Hard failure. Reject everything except QUIT or closed connection. One
5553 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5554 set, but we must still reject all incoming commands. Another is a handshake
5555 failure - and there may some encrypted data still in the pipe to us, which we
5556 see as garbage commands. */
5558 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5559 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5562 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5563 smtp_get_connection_info());
5564 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5568 /* It is perhaps arguable as to which exit ACL should be called here,
5569 but as it is probably a situation that almost never arises, it
5570 probably doesn't matter. We choose to call the real QUIT ACL, which in
5571 some sense is perhaps "right". */
5576 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5577 &log_msg)) == ERROR))
5578 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5581 smtp_respond(US"221", 3, TRUE, user_msg);
5583 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5584 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5585 smtp_get_connection_info());
5590 smtp_printf("554 Security failure\r\n", FALSE);
5593 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5598 /* The ACL for QUIT is provided for gathering statistical information or
5599 similar; it does not affect the response code, but it can supply a custom
5603 smtp_quit_handler(&user_msg, &log_msg);
5609 smtp_rset_handler();
5610 cancel_cutthrough_connection(TRUE, US"RSET received");
5611 reset_point = smtp_reset(reset_point);
5618 smtp_printf("250 OK\r\n", FALSE);
5622 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5623 used, a check will be done for permitted hosts. Show STARTTLS only if not
5624 already in a TLS session and if it would be advertised in the EHLO
5629 smtp_printf("214-Commands supported:\r\n", TRUE);
5633 Ustrcat(buffer, US" AUTH");
5635 if (tls_in.active.sock < 0 &&
5636 verify_check_host(&tls_advertise_hosts) != FAIL)
5637 Ustrcat(buffer, US" STARTTLS");
5639 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5640 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5641 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5642 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5643 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5644 smtp_printf("214%s\r\n", FALSE, buffer);
5650 incomplete_transaction_log(US"connection lost");
5651 smtp_notquit_exit(US"connection-lost", US"421",
5652 US"%s lost input connection", smtp_active_hostname);
5654 /* Don't log by default unless in the middle of a message, as some mailers
5655 just drop the call rather than sending QUIT, and it clutters up the logs.
5658 if (sender_address || recipients_count > 0)
5659 log_write(L_lost_incoming_connection, LOG_MAIN,
5660 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5661 f.sender_host_unknown ? "EOF" : "disconnection",
5662 f.tcp_in_fastopen_logged
5665 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5667 host_and_ident(FALSE), smtp_read_error,
5668 string_timesince(&smtp_connection_start)
5672 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5673 smtp_get_connection_info(),
5674 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5676 string_timesince(&smtp_connection_start)
5687 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5688 US"ETRN is not permitted inside a transaction");
5692 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5693 host_and_ident(FALSE));
5695 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5696 &user_msg, &log_msg)) != OK)
5698 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5702 /* Compute the serialization key for this command. */
5704 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5706 /* If a command has been specified for running as a result of ETRN, we
5707 permit any argument to ETRN. If not, only the # standard form is permitted,
5708 since that is strictly the only kind of ETRN that can be implemented
5709 according to the RFC. */
5711 if (smtp_etrn_command)
5715 etrn_command = smtp_etrn_command;
5716 deliver_domain = smtp_cmd_data;
5717 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5718 US"ETRN processing", &error);
5719 deliver_domain = NULL;
5722 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5724 smtp_printf("458 Internal failure\r\n", FALSE);
5729 /* Else set up to call Exim with the -R option. */
5733 if (*smtp_cmd_data++ != '#')
5735 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5736 US"argument must begin with #");
5739 etrn_command = US"exim -R";
5740 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5741 *queue_name ? 4 : 2,
5742 US"-R", smtp_cmd_data,
5743 US"-MCG", queue_name);
5746 /* If we are host-testing, don't actually do anything. */
5752 debug_printf("ETRN command is: %s\n", etrn_command);
5753 debug_printf("ETRN command execution skipped\n");
5755 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5756 else smtp_user_msg(US"250", user_msg);
5761 /* If ETRN queue runs are to be serialized, check the database to
5762 ensure one isn't already running. */
5764 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5766 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5770 /* Fork a child process and run the command. We don't want to have to
5771 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5772 forking. It should be set that way anyway for external incoming SMTP,
5773 but we save and restore to be tidy. If serialization is required, we
5774 actually run the command in yet another process, so we can wait for it
5775 to complete and then remove the serialization lock. */
5777 oldsignal = signal(SIGCHLD, SIG_IGN);
5779 if ((pid = exim_fork(US"etrn-command")) == 0)
5781 smtp_input = FALSE; /* This process is not associated with the */
5782 (void)fclose(smtp_in); /* SMTP call any more. */
5783 (void)fclose(smtp_out);
5785 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5787 /* If not serializing, do the exec right away. Otherwise, fork down
5788 into another process. */
5790 if ( !smtp_etrn_serialize
5791 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5793 DEBUG(D_exec) debug_print_argv(argv);
5794 exim_nullstd(); /* Ensure std{in,out,err} exist */
5795 execv(CS argv[0], (char *const *)argv);
5796 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5797 etrn_command, strerror(errno));
5798 _exit(EXIT_FAILURE); /* paranoia */
5801 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5802 is, we are in the first subprocess, after forking again. All we can do
5803 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5804 complete, before removing the serialization. */
5807 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5808 "failed: %s", strerror(errno));
5812 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5814 (void)wait(&status);
5815 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5819 enq_end(etrn_serialize_key);
5820 exim_underbar_exit(EXIT_SUCCESS);
5823 /* Back in the top level SMTP process. Check that we started a subprocess
5824 and restore the signal state. */
5828 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5830 smtp_printf("458 Unable to fork process\r\n", FALSE);
5831 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5835 smtp_printf("250 OK\r\n", FALSE);
5837 smtp_user_msg(US"250", user_msg);
5839 signal(SIGCHLD, oldsignal);
5844 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5845 US"unexpected argument data");
5849 /* This currently happens only for NULLs, but could be extended. */
5852 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5853 US"NUL character(s) present (shown as '?')");
5854 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5861 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5862 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5863 c = smtp_inend - smtp_inptr;
5864 if (c > 150) c = 150; /* limit logged amount */
5866 incomplete_transaction_log(US"sync failure");
5867 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5868 "(next input sent too soon: pipelining was%s advertised): "
5869 "rejected \"%s\" %s next input=\"%s\"",
5870 f.smtp_in_pipelining_advertised ? "" : " not",
5871 smtp_cmd_buffer, host_and_ident(TRUE),
5872 string_printing(smtp_inptr));
5873 smtp_notquit_exit(US"synchronization-error", US"554",
5874 US"SMTP synchronization error");
5875 done = 1; /* Pretend eof - drops connection */
5879 case TOO_MANY_NONMAIL_CMD:
5880 s = smtp_cmd_buffer;
5881 while (*s != 0 && !isspace(*s)) s++;
5882 incomplete_transaction_log(US"too many non-mail commands");
5883 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5884 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5885 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5886 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5887 done = 1; /* Pretend eof - drops connection */
5890 #ifdef SUPPORT_PROXY
5891 case PROXY_FAIL_IGNORE_CMD:
5892 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5897 if (unknown_command_count++ >= smtp_max_unknown_commands)
5899 log_write(L_smtp_syntax_error, LOG_MAIN,
5900 "SMTP syntax error in \"%s\" %s %s",
5901 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5902 US"unrecognized command");
5903 incomplete_transaction_log(US"unrecognized command");
5904 smtp_notquit_exit(US"bad-commands", US"500",
5905 US"Too many unrecognized commands");
5907 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5908 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5909 string_printing(smtp_cmd_buffer));
5912 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5913 US"unrecognized command");
5917 /* This label is used by goto's inside loops that want to break out to
5918 the end of the command-processing loop. */
5921 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5922 last_was_rcpt = was_rcpt; /* protocol error handling */
5926 return done - 2; /* Convert yield values */
5932 authres_smtpauth(gstring * g)
5934 if (!sender_host_authenticated)
5937 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5939 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5940 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5941 else if (authenticated_id)
5942 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5944 g = string_catn(g, US") reason=x509.auth", 17);
5946 if (authenticated_sender)
5947 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5955 /* End of smtp_in.c */