1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 uschar * smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Recheck synchronization *
324 *************************************************/
326 /* Synchronization checks can never be perfect because a packet may be on its
327 way but not arrived when the check is done. Normally, the checks happen when
328 commands are read: Exim ensures that there is no more input in the input buffer.
329 In normal cases, the response to the command will be fast, and there is no
332 However, for some commands an ACL is run, and that can include delays. In those
333 cases, it is useful to do another check on the input just before sending the
334 response. This also applies at the start of a connection. This function does
335 that check by means of the select() function, as long as the facility is not
336 disabled or inappropriate. A failure of select() is ignored.
338 When there is unwanted input, we read it so that it appears in the log of the
342 Returns: TRUE if all is well; FALSE if there is input pending
346 wouldblock_reading(void)
350 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
353 if (tls_in.active.sock >= 0)
354 return !tls_could_read();
357 if (smtp_inptr < smtp_inend)
360 fd = fileno(smtp_in);
363 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
365 if (rc <= 0) return TRUE; /* Not ready to read */
366 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
367 if (rc < 0) return TRUE; /* End of file or error */
376 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
379 return wouldblock_reading();
383 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
384 a reponse with the one following. */
387 pipeline_response(void)
389 if ( !smtp_enforce_sync || !sender_host_address
390 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
393 if (wouldblock_reading()) return FALSE;
394 f.smtp_in_pipelining_used = TRUE;
399 #ifndef DISABLE_PIPE_CONNECT
401 pipeline_connect_sends(void)
403 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
406 if (wouldblock_reading()) return FALSE;
407 f.smtp_in_early_pipe_used = TRUE;
412 /*************************************************
413 * Log incomplete transactions *
414 *************************************************/
416 /* This function is called after a transaction has been aborted by RSET, QUIT,
417 connection drops or other errors. It logs the envelope information received
418 so far in order to preserve address verification attempts.
420 Argument: string to indicate what aborted the transaction
425 incomplete_transaction_log(uschar *what)
427 if (!sender_address /* No transaction in progress */
428 || !LOGGING(smtp_incomplete_transaction))
431 /* Build list of recipients for logging */
433 if (recipients_count > 0)
435 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
436 for (int i = 0; i < recipients_count; i++)
437 raw_recipients[i] = recipients_list[i].address;
438 raw_recipients_count = recipients_count;
441 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
442 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
449 smtp_command_timeout_exit(void)
451 log_write(L_lost_incoming_connection,
452 LOG_MAIN, "SMTP command timeout on%s connection from %s",
453 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
454 if (smtp_batched_input)
455 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
456 smtp_notquit_exit(US"command-timeout", US"421",
457 US"%s: SMTP command timeout - closing connection",
458 smtp_active_hostname);
459 exim_exit(EXIT_FAILURE);
463 smtp_command_sigterm_exit(void)
465 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
466 if (smtp_batched_input)
467 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
468 smtp_notquit_exit(US"signal-exit", US"421",
469 US"%s: Service not available - closing connection", smtp_active_hostname);
470 exim_exit(EXIT_FAILURE);
474 smtp_data_timeout_exit(void)
476 log_write(L_lost_incoming_connection,
477 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
478 sender_fullhost ? sender_fullhost : US"local process", sender_address);
479 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
480 /* Does not return */
484 smtp_data_sigint_exit(void)
486 log_write(0, LOG_MAIN, "%s closed after %s",
487 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
488 receive_bomb_out(US"signal-exit",
489 US"Service not available - SIGTERM or SIGINT received");
490 /* Does not return */
495 /* Refill the buffer, and notify DKIM verification code.
496 Return false for error or EOF.
500 smtp_refill(unsigned lim)
503 if (!smtp_out) return FALSE;
505 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
507 /* Limit amount read, so non-message data is not fed to DKIM.
508 Take care to not touch the safety NUL at the end of the buffer. */
510 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
512 if (smtp_receive_timeout > 0) ALARM_CLR(0);
515 /* Must put the error text in fixed store, because this might be during
516 header reading, where it releases unused store above the header. */
519 if (had_command_timeout) /* set by signal handler */
520 smtp_command_timeout_exit(); /* does not return */
521 if (had_command_sigterm)
522 smtp_command_sigterm_exit();
523 if (had_data_timeout)
524 smtp_data_timeout_exit();
526 smtp_data_sigint_exit();
528 smtp_had_error = save_errno;
529 smtp_read_error = string_copy_perm(
530 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
537 dkim_exim_verify_feed(smtp_inbuffer, rc);
539 smtp_inend = smtp_inbuffer + rc;
540 smtp_inptr = smtp_inbuffer;
544 /*************************************************
545 * SMTP version of getc() *
546 *************************************************/
548 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
549 it flushes the output, and refills the buffer, with a timeout. The signal
550 handler is set appropriately by the calling function. This function is not used
551 after a connection has negotiated itself into an TLS/SSL state.
553 Arguments: lim Maximum amount to read/buffer
554 Returns: the next character or EOF
558 smtp_getc(unsigned lim)
560 if (smtp_inptr >= smtp_inend)
561 if (!smtp_refill(lim))
563 return *smtp_inptr++;
567 smtp_getbuf(unsigned * len)
572 if (smtp_inptr >= smtp_inend)
573 if (!smtp_refill(*len))
574 { *len = 0; return NULL; }
576 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
587 int n = smtp_inend - smtp_inptr;
588 if (chunking_state == CHUNKING_LAST && chunking_data_left < n)
589 n = chunking_data_left;
591 dkim_exim_verify_feed(smtp_inptr, n);
596 /* 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 bdat_pop_receive_functions();
629 dkim_save = dkim_collect_input;
630 dkim_collect_input = 0;
633 /* Unless PIPELINING was offered, there should be no next command
634 until after we ack that chunk */
636 if (!f.smtp_in_pipelining_advertised && !check_sync())
638 unsigned n = smtp_inend - smtp_inptr;
641 incomplete_transaction_log(US"sync failure");
642 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
643 "(next input sent too soon: pipelining was not advertised): "
644 "rejected \"%s\" %s next input=\"%s\"%s",
645 smtp_cmd_buffer, host_and_ident(TRUE),
646 string_printing(string_copyn(smtp_inptr, n)),
647 smtp_inend - smtp_inptr > n ? "..." : "");
648 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
649 US"SMTP synchronization error");
650 goto repeat_until_rset;
653 /* If not the last, ack the received chunk. The last response is delayed
654 until after the data ACL decides on it */
656 if (chunking_state == CHUNKING_LAST)
659 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
664 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
665 chunking_state = CHUNKING_OFFERED;
666 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
668 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
669 QUIT, RSET or NOOP but handling them seems obvious */
672 switch(smtp_read_command(TRUE, 1))
675 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
676 US"only BDAT permissible after non-LAST BDAT");
679 switch(smtp_read_command(TRUE, 1))
681 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
682 case EOF_CMD: return EOF;
683 case RSET_CMD: smtp_rset_handler(); return ERR;
684 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
685 US"only RSET accepted now") > 0)
687 goto repeat_until_rset;
691 smtp_quit_handler(&user_msg, &log_msg);
702 smtp_printf("250 OK\r\n", FALSE);
709 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
711 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
712 US"missing size for BDAT command");
715 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
716 ? CHUNKING_LAST : CHUNKING_ACTIVE;
717 chunking_data_left = chunking_datasize;
718 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
719 (int)chunking_state, chunking_data_left);
721 if (chunking_datasize == 0)
722 if (chunking_state == CHUNKING_LAST)
726 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
727 US"zero size for BDAT command");
728 goto repeat_until_rset;
731 bdat_push_receive_functions();
733 dkim_collect_input = dkim_save;
735 break; /* to top of main loop */
742 bdat_getbuf(unsigned * len)
746 if (chunking_data_left <= 0)
747 { *len = 0; return NULL; }
749 if (*len > chunking_data_left) *len = chunking_data_left;
750 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
751 chunking_data_left -= *len;
756 bdat_flush_data(void)
758 while (chunking_data_left)
760 unsigned n = chunking_data_left;
761 if (!bdat_getbuf(&n)) break;
764 bdat_pop_receive_functions();
766 if (chunking_state != CHUNKING_LAST)
768 chunking_state = CHUNKING_OFFERED;
769 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
775 bdat_push_receive_functions(void)
777 /* push the current receive_* function on the "stack", and
778 replace them by bdat_getc(), which in turn will use the lwr_receive_*
779 functions to do the dirty work. */
780 if (lwr_receive_getc == NULL)
782 lwr_receive_getc = receive_getc;
783 lwr_receive_getbuf = receive_getbuf;
784 lwr_receive_ungetc = receive_ungetc;
788 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
791 receive_getc = bdat_getc;
792 receive_ungetc = bdat_ungetc;
796 bdat_pop_receive_functions(void)
798 receive_getc = lwr_receive_getc;
799 receive_getbuf = lwr_receive_getbuf;
800 receive_ungetc = lwr_receive_ungetc;
801 lwr_receive_getc = lwr_receive_getbuf = lwr_receive_ungetc = NULL;
804 /*************************************************
805 * SMTP version of ungetc() *
806 *************************************************/
808 /* Puts a character back in the input buffer. Only ever
814 Returns: the character
828 chunking_data_left++;
829 return lwr_receive_ungetc(ch);
834 /*************************************************
835 * SMTP version of feof() *
836 *************************************************/
838 /* Tests for a previous EOF
841 Returns: non-zero if the eof flag is set
853 /*************************************************
854 * SMTP version of ferror() *
855 *************************************************/
857 /* Tests for a previous read error, and returns with errno
858 restored to what it was when the error was detected.
861 Returns: non-zero if the error flag is set
867 errno = smtp_had_error;
868 return smtp_had_error;
873 /*************************************************
874 * Test for characters in the SMTP buffer *
875 *************************************************/
877 /* Used at the end of a message
886 return smtp_inptr < smtp_inend;
891 /*************************************************
892 * Write formatted string to SMTP channel *
893 *************************************************/
895 /* This is a separate function so that we don't have to repeat everything for
896 TLS support or debugging. It is global so that the daemon and the
897 authentication functions can use it. It does not return any error indication,
898 because major problems such as dropped connections won't show up till an output
899 flush for non-TLS connections. The smtp_fflush() function is available for
900 checking that: for convenience, TLS output errors are remembered here so that
901 they are also picked up later by smtp_fflush().
903 This function is exposed to the local_scan API; do not change the signature.
907 more further data expected
908 ... optional arguments
914 smtp_printf(const char *format, BOOL more, ...)
919 smtp_vprintf(format, more, ap);
923 /* This is split off so that verify.c:respond_printf() can, in effect, call
924 smtp_printf(), bearing in mind that in C a vararg function can't directly
925 call another vararg function, only a function which accepts a va_list.
927 This function is exposed to the local_scan API; do not change the signature.
929 /*XXX consider passing caller-info in, for string_vformat-onward */
932 smtp_vprintf(const char *format, BOOL more, va_list ap)
934 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
937 /* Use taint-unchecked routines for writing into big_buffer, trusting
938 that we'll never expand it. */
940 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
941 string_from_gstring(&gs);
945 uschar *msg_copy, *cr, *end;
946 msg_copy = string_copy(gs.s);
947 end = msg_copy + gs.ptr;
948 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
949 memmove(cr, cr + 1, (end--) - cr);
950 debug_printf("SMTP>> %s", msg_copy);
955 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
956 smtp_closedown(US"Unexpected error");
957 exim_exit(EXIT_FAILURE);
960 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
961 have had the same. Note: this code is also present in smtp_respond(). It would
962 be tidier to have it only in one place, but when it was added, it was easier to
963 do it that way, so as not to have to mess with the code for the RCPT command,
964 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
966 if (fl.rcpt_in_progress)
968 if (rcpt_smtp_response == NULL)
969 rcpt_smtp_response = string_copy(big_buffer);
970 else if (fl.rcpt_smtp_response_same &&
971 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
972 fl.rcpt_smtp_response_same = FALSE;
973 fl.rcpt_in_progress = FALSE;
976 /* Now write the string */
980 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
982 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
984 smtp_write_error = -1;
989 /*************************************************
990 * Flush SMTP out and check for error *
991 *************************************************/
993 /* This function isn't currently used within Exim (it detects errors when it
994 tries to read the next SMTP input), but is available for use in local_scan().
995 It flushes the output and checks for errors.
998 Returns: 0 for no error; -1 after an error
1004 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1008 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1010 (fflush(smtp_out) != 0)
1012 smtp_write_error = -1;
1014 return smtp_write_error;
1019 /*************************************************
1020 * SMTP command read timeout *
1021 *************************************************/
1023 /* Signal handler for timing out incoming SMTP commands. This attempts to
1026 Argument: signal number (SIGALRM)
1031 command_timeout_handler(int sig)
1033 had_command_timeout = sig;
1038 /*************************************************
1039 * SIGTERM received *
1040 *************************************************/
1042 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1044 Argument: signal number (SIGTERM)
1049 command_sigterm_handler(int sig)
1051 had_command_sigterm = sig;
1057 #ifdef SUPPORT_PROXY
1058 /*************************************************
1059 * Check if host is required proxy host *
1060 *************************************************/
1061 /* The function determines if inbound host will be a regular smtp host
1062 or if it is configured that it must use Proxy Protocol. A local
1070 check_proxy_protocol_host()
1074 if ( sender_host_address
1075 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1076 sender_host_address, NULL)) == OK)
1079 debug_printf("Detected proxy protocol configured host\n");
1080 proxy_session = TRUE;
1082 return proxy_session;
1086 /*************************************************
1087 * Read data until newline or end of buffer *
1088 *************************************************/
1089 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1090 read an entire buffer and assume there will be nothing past a proxy protocol
1091 header. Our approach normally is to use stdio, but again that relies upon
1092 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1093 reading _nothing_ before client TLS handshake. So we don't want to use the
1094 usual buffering reads which may read enough to block TLS starting.
1096 So unfortunately we're down to "read one byte at a time, with a syscall each,
1097 and expect a little overhead", for all proxy-opened connections which are v1,
1098 just to handle the TLS-on-connect case. Since SSL functions wrap the
1099 underlying fd, we can't assume that we can feed them any already-read content.
1101 We need to know where to read to, the max capacity, and we'll read until we
1102 get a CR and one more character. Let the caller scream if it's CR+!LF.
1104 Return the amount read.
1108 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1110 uschar *to = base + already;
1116 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1117 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1119 cr = memchr(base, '\r', already);
1122 if ((cr - base) < already - 1)
1124 /* \r and presumed \n already within what we have; probably not
1125 actually proxy protocol, but abort cleanly. */
1128 /* \r is last character read, just need one more. */
1132 while (capacity > 0)
1134 do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
1146 /* reached end without having room for a final newline, abort */
1151 /*************************************************
1152 * Setup host for proxy protocol *
1153 *************************************************/
1154 /* The function configures the connection based on a header from the
1155 inbound host to use Proxy Protocol. The specification is very exact
1156 so exit with an error if do not find the exact required pieces. This
1157 includes an incorrect number of spaces separating args.
1160 Returns: Boolean success
1164 setup_proxy_protocol_host()
1176 struct { /* TCP/UDP over IPv4, len = 12 */
1182 struct { /* TCP/UDP over IPv6, len = 36 */
1183 uint8_t src_addr[16];
1184 uint8_t dst_addr[16];
1188 struct { /* AF_UNIX sockets, len = 216 */
1189 uschar src_addr[108];
1190 uschar dst_addr[108];
1196 /* Temp variables used in PPv2 address:port parsing */
1198 char tmpip[INET_ADDRSTRLEN];
1199 struct sockaddr_in tmpaddr;
1200 char tmpip6[INET6_ADDRSTRLEN];
1201 struct sockaddr_in6 tmpaddr6;
1203 /* We can't read "all data until end" because while SMTP is
1204 server-speaks-first, the TLS handshake is client-speaks-first, so for
1205 TLS-on-connect ports the proxy protocol header will usually be immediately
1206 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1207 reinject data for reading by those. So instead we first read "enough to be
1208 safely read within the header, and figure out how much more to read".
1209 For v1 we will later read to the end-of-line, for v2 we will read based upon
1212 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1213 data is needed total. For v1, where the line looks like:
1214 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1216 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1217 We seem to support that. So, if we read 14 octets then we can tell if we're
1218 v2 or v1. If we're v1, we can continue reading as normal.
1220 If we're v2, we can't slurp up the entire header. We need the length in the
1221 15th & 16th octets, then to read everything after that.
1223 So to safely handle v1 and v2, with client-sent-first supported correctly,
1224 we have to do a minimum of 3 read calls, not 1. Eww.
1227 #define PROXY_INITIAL_READ 14
1228 #define PROXY_V2_HEADER_SIZE 16
1229 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1230 # error Code bug in sizes of data to read for proxy usage
1235 int fd = fileno(smtp_in);
1236 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1237 uschar * iptype; /* To display debug info */
1238 socklen_t vslen = sizeof(struct timeval);
1241 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1242 ALARM(proxy_protocol_timeout);
1246 /* The inbound host was declared to be a Proxy Protocol host, so
1247 don't do a PEEK into the data, actually slurp up enough to be
1248 "safe". Can't take it all because TLS-on-connect clients follow
1249 immediately with TLS handshake. */
1250 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1252 while (ret == -1 && errno == EINTR && !had_command_timeout);
1257 /* For v2, handle reading the length, and then the rest. */
1258 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1263 /* First get the length fields. */
1266 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1267 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1272 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1274 /* May 2014: haproxy combined the version and command into one byte to
1275 allow two full bytes for the length field in order to proxy SSL
1276 connections. SSL Proxy is not supported in this version of Exim, but
1277 must still separate values here. */
1281 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1285 /* The v2 header will always be 16 bytes per the spec. */
1286 size = 16 + ntohs(hdr.v2.len);
1287 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1288 size, (int)sizeof(hdr));
1290 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1291 amount that we need. Double-check that the size is not unreasonable, then
1293 if (size > sizeof(hdr))
1295 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1303 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1304 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1308 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1309 } while (ret < size);
1311 } /* end scope for getting rest of data for v2 */
1313 /* At this point: if PROXYv2, we've read the exact size required for all data;
1314 if PROXYv1 then we've read "less than required for any valid line" and should
1317 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1319 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1323 case 0x01: /* PROXY command */
1326 case 0x11: /* TCPv4 address type */
1328 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1329 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1330 if (!string_is_ip_address(US tmpip, NULL))
1332 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1335 proxy_local_address = sender_host_address;
1336 sender_host_address = string_copy(US tmpip);
1337 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1338 proxy_local_port = sender_host_port;
1339 sender_host_port = tmpport;
1340 /* Save dest ip/port */
1341 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1342 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1343 if (!string_is_ip_address(US tmpip, NULL))
1345 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1348 proxy_external_address = string_copy(US tmpip);
1349 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1350 proxy_external_port = tmpport;
1352 case 0x21: /* TCPv6 address type */
1354 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1355 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1356 if (!string_is_ip_address(US tmpip6, NULL))
1358 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1361 proxy_local_address = sender_host_address;
1362 sender_host_address = string_copy(US tmpip6);
1363 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1364 proxy_local_port = sender_host_port;
1365 sender_host_port = tmpport;
1366 /* Save dest ip/port */
1367 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1368 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1369 if (!string_is_ip_address(US tmpip6, NULL))
1371 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1374 proxy_external_address = string_copy(US tmpip6);
1375 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1376 proxy_external_port = tmpport;
1380 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1384 /* Unsupported protocol, keep local connection address */
1386 case 0x00: /* LOCAL command */
1387 /* Keep local connection address for LOCAL */
1392 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1396 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1400 uschar *sp; /* Utility variables follow */
1405 /* get the rest of the line */
1406 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1411 p = string_copy(hdr.v1.line);
1412 end = memchr(p, '\r', ret - 1);
1414 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1416 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1419 *end = '\0'; /* Terminate the string */
1420 size = end + 2 - p; /* Skip header + CRLF */
1421 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1422 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1423 /* Step through the string looking for the required fields. Ensure
1424 strict adherence to required formatting, exit for any error. */
1426 if (!isspace(*(p++)))
1428 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1431 if (!Ustrncmp(p, CCS"TCP4", 4))
1433 else if (!Ustrncmp(p,CCS"TCP6", 4))
1435 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1437 iptype = US"Unknown";
1442 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1446 p += Ustrlen(iptype);
1447 if (!isspace(*(p++)))
1449 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1452 /* Find the end of the arg */
1453 if ((sp = Ustrchr(p, ' ')) == NULL)
1456 debug_printf("Did not find proxied src %s\n", iptype);
1460 if(!string_is_ip_address(p, NULL))
1463 debug_printf("Proxied src arg is not an %s address\n", iptype);
1466 proxy_local_address = sender_host_address;
1467 sender_host_address = p;
1469 if ((sp = Ustrchr(p, ' ')) == NULL)
1472 debug_printf("Did not find proxy dest %s\n", iptype);
1476 if(!string_is_ip_address(p, NULL))
1479 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1482 proxy_external_address = p;
1484 if ((sp = Ustrchr(p, ' ')) == NULL)
1486 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1490 tmp_port = strtol(CCS p, &endc, 10);
1491 if (*endc || tmp_port == 0)
1494 debug_printf("Proxied src port '%s' not an integer\n", p);
1497 proxy_local_port = sender_host_port;
1498 sender_host_port = tmp_port;
1500 if ((sp = Ustrchr(p, '\0')) == NULL)
1502 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1505 tmp_port = strtol(CCS p, &endc, 10);
1506 if (*endc || tmp_port == 0)
1509 debug_printf("Proxy dest port '%s' not an integer\n", p);
1512 proxy_external_port = tmp_port;
1513 /* Already checked for /r /n above. Good V1 header received. */
1517 /* Wrong protocol */
1518 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1519 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1525 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1526 yield = proxy_session;
1528 /* Don't flush any potential buffer contents. Any input on proxyfail
1529 should cause a synchronization failure */
1532 DEBUG(D_receive) if (had_command_timeout)
1533 debug_printf("Timeout while reading proxy header\n");
1538 sender_host_name = NULL;
1539 (void) host_name_lookup();
1540 host_build_sender_fullhost();
1544 f.proxy_session_failed = TRUE;
1546 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1554 /*************************************************
1555 * Read one command line *
1556 *************************************************/
1558 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1559 There are sites that don't do this, and in any case internal SMTP probably
1560 should check only for LF. Consequently, we check here for LF only. The line
1561 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1562 an unknown command. The command is read into the global smtp_cmd_buffer so that
1563 it is available via $smtp_command.
1565 The character reading routine sets up a timeout for each block actually read
1566 from the input (which may contain more than one command). We set up a special
1567 signal handler that closes down the session on a timeout. Control does not
1568 return when it runs.
1571 check_sync if TRUE, check synchronization rules if global option is TRUE
1572 buffer_lim maximum to buffer in lower layer
1574 Returns: a code identifying the command (enumerated above)
1578 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1582 BOOL hadnull = FALSE;
1584 had_command_timeout = 0;
1585 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1587 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1589 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1591 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1599 smtp_cmd_buffer[ptr++] = c;
1602 receive_linecount++; /* For BSMTP errors */
1603 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1605 /* If hit end of file, return pseudo EOF command. Whether we have a
1606 part-line already read doesn't matter, since this is an error state. */
1608 if (c == EOF) return EOF_CMD;
1610 /* Remove any CR and white space at the end of the line, and terminate the
1613 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1614 smtp_cmd_buffer[ptr] = 0;
1616 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1618 /* NULLs are not allowed in SMTP commands */
1620 if (hadnull) return BADCHAR_CMD;
1622 /* Scan command list and return identity, having set the data pointer
1623 to the start of the actual data characters. Check for SMTP synchronization
1626 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1628 #ifdef SUPPORT_PROXY
1629 /* Only allow QUIT command if Proxy Protocol parsing failed */
1630 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1634 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1635 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1636 || smtp_cmd_buffer[p->len] == 0
1637 || smtp_cmd_buffer[p->len] == ' '
1640 if (smtp_inptr < smtp_inend && /* Outstanding input */
1641 p->cmd < sync_cmd_limit && /* Command should sync */
1642 check_sync && /* Local flag set */
1643 smtp_enforce_sync && /* Global flag set */
1644 sender_host_address != NULL && /* Not local input */
1645 !f.sender_host_notsocket) /* Really is a socket */
1648 /* The variables $smtp_command and $smtp_command_argument point into the
1649 unmodified input buffer. A copy of the latter is taken for actual
1650 processing, so that it can be chopped up into separate parts if necessary,
1651 for example, when processing a MAIL command options such as SIZE that can
1652 follow the sender address. */
1654 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1655 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1656 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1657 smtp_cmd_data = smtp_data_buffer;
1659 /* Count non-mail commands from those hosts that are controlled in this
1660 way. The default is all hosts. We don't waste effort checking the list
1661 until we get a non-mail command, but then cache the result to save checking
1662 again. If there's a DEFER while checking the host, assume it's in the list.
1664 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1665 start of each incoming message by fiddling with the value in the table. */
1667 if (!p->is_mail_cmd)
1669 if (count_nonmail == TRUE_UNSET) count_nonmail =
1670 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1671 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1672 return TOO_MANY_NONMAIL_CMD;
1675 /* If there is data for a command that does not expect it, generate the
1678 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1682 #ifdef SUPPORT_PROXY
1683 /* Only allow QUIT command if Proxy Protocol parsing failed */
1684 if (proxy_session && f.proxy_session_failed)
1685 return PROXY_FAIL_IGNORE_CMD;
1688 /* Enforce synchronization for unknown commands */
1690 if ( smtp_inptr < smtp_inend /* Outstanding input */
1691 && check_sync /* Local flag set */
1692 && smtp_enforce_sync /* Global flag set */
1693 && sender_host_address /* Not local input */
1694 && !f.sender_host_notsocket) /* Really is a socket */
1702 /*************************************************
1703 * Forced closedown of call *
1704 *************************************************/
1706 /* This function is called from log.c when Exim is dying because of a serious
1707 disaster, and also from some other places. If an incoming non-batched SMTP
1708 channel is open, it swallows the rest of the incoming message if in the DATA
1709 phase, sends the reply string, and gives an error to all subsequent commands
1710 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1714 message SMTP reply string to send, excluding the code
1720 smtp_closedown(uschar *message)
1722 if (!smtp_in || smtp_batched_input) return;
1723 receive_swallow_smtp();
1724 smtp_printf("421 %s\r\n", FALSE, message);
1726 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1732 f.smtp_in_quit = TRUE;
1733 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1738 smtp_printf("250 Reset OK\r\n", FALSE);
1742 smtp_printf("421 %s\r\n", FALSE, message);
1750 /*************************************************
1751 * Set up connection info for logging *
1752 *************************************************/
1754 /* This function is called when logging information about an SMTP connection.
1755 It sets up appropriate source information, depending on the type of connection.
1756 If sender_fullhost is NULL, we are at a very early stage of the connection;
1757 just use the IP address.
1760 Returns: a string describing the connection
1764 smtp_get_connection_info(void)
1766 const uschar * hostname = sender_fullhost
1767 ? sender_fullhost : sender_host_address;
1770 return string_sprintf("SMTP connection from %s", hostname);
1772 if (f.sender_host_unknown || f.sender_host_notsocket)
1773 return string_sprintf("SMTP connection from %s", sender_ident);
1776 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1778 if (LOGGING(incoming_interface) && interface_address)
1779 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1780 interface_address, interface_port);
1782 return string_sprintf("SMTP connection from %s", hostname);
1788 /* Append TLS-related information to a log line
1791 g String under construction: allocated string to extend, or NULL
1793 Returns: Allocated string or NULL
1796 s_tlslog(gstring * g)
1798 if (LOGGING(tls_cipher) && tls_in.cipher)
1800 g = string_append(g, 2, US" X=", tls_in.cipher);
1801 #ifndef DISABLE_TLS_RESUME
1802 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1803 g = string_catn(g, US"*", 1);
1806 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1807 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1808 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1809 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1810 if (LOGGING(tls_sni) && tls_in.sni)
1811 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1819 s_connhad_log(gstring * g)
1821 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1822 ? US" C=..." : US" C=";
1824 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1825 if (smtp_connection_had[i] != SCH_NONE)
1827 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1830 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1831 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1836 /*************************************************
1837 * Log lack of MAIL if so configured *
1838 *************************************************/
1840 /* This function is called when an SMTP session ends. If the log selector
1841 smtp_no_mail is set, write a log line giving some details of what has happened
1842 in the SMTP session.
1849 smtp_log_no_mail(void)
1854 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1857 if (sender_host_authenticated)
1859 g = string_append(g, 2, US" A=", sender_host_authenticated);
1860 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1867 g = s_connhad_log(g);
1869 if (!(s = string_from_gstring(g))) s = US"";
1871 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1872 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1873 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1877 /* Return list of recent smtp commands */
1882 gstring * list = NULL;
1885 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1886 if (smtp_connection_had[i] != SCH_NONE)
1887 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1889 for (int i = 0; i < smtp_ch_index; i++)
1890 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1892 s = string_from_gstring(list);
1893 return s ? s : US"";
1899 /*************************************************
1900 * Check HELO line and set sender_helo_name *
1901 *************************************************/
1903 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1904 the domain name of the sending host, or an ip literal in square brackets. The
1905 argument is placed in sender_helo_name, which is in malloc store, because it
1906 must persist over multiple incoming messages. If helo_accept_junk is set, this
1907 host is permitted to send any old junk (needed for some broken hosts).
1908 Otherwise, helo_allow_chars can be used for rogue characters in general
1909 (typically people want to let in underscores).
1912 s the data portion of the line (already past any white space)
1914 Returns: TRUE or FALSE
1918 check_helo(uschar *s)
1921 uschar *end = s + Ustrlen(s);
1922 BOOL yield = fl.helo_accept_junk;
1924 /* Discard any previous helo name */
1926 sender_helo_name = NULL;
1928 /* Skip tests if junk is permitted. */
1932 /* Allow the new standard form for IPv6 address literals, namely,
1933 [IPv6:....], and because someone is bound to use it, allow an equivalent
1934 IPv4 form. Allow plain addresses as well. */
1941 if (strncmpic(s, US"[IPv6:", 6) == 0)
1942 yield = (string_is_ip_address(s+6, NULL) == 6);
1943 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1944 yield = (string_is_ip_address(s+6, NULL) == 4);
1946 yield = (string_is_ip_address(s+1, NULL) != 0);
1951 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1952 that have been configured (usually underscore - sigh). */
1955 for (yield = TRUE; *s; s++)
1956 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1957 Ustrchr(helo_allow_chars, *s) == NULL)
1963 /* Save argument if OK */
1965 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1973 /*************************************************
1974 * Extract SMTP command option *
1975 *************************************************/
1977 /* This function picks the next option setting off the end of smtp_cmd_data. It
1978 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1979 things that can appear there.
1982 name point this at the name
1983 value point this at the data string
1985 Returns: TRUE if found an option
1989 extract_option(uschar **name, uschar **value)
1992 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1993 while (isspace(*v)) v--;
1995 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1997 /* Take care to not stop at a space embedded in a quoted local-part */
1999 if ((*v == '"') && (v > smtp_cmd_data + 1))
2000 do v--; while (*v != '"' && v > smtp_cmd_data+1);
2007 while(isalpha(n[-1])) n--;
2008 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2009 if (!isspace(n[-1])) return FALSE;
2015 if (v == smtp_cmd_data) return FALSE;
2027 /*************************************************
2028 * Reset for new message *
2029 *************************************************/
2031 /* This function is called whenever the SMTP session is reset from
2032 within either of the setup functions; also from the daemon loop.
2034 Argument: the stacking pool storage reset point
2039 smtp_reset(void *reset_point)
2041 recipients_list = NULL;
2042 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2043 raw_recipients_count = recipients_count = recipients_list_max = 0;
2044 message_linecount = 0;
2046 message_body = message_body_end = NULL;
2047 acl_added_headers = NULL;
2048 acl_removed_headers = NULL;
2049 f.queue_only_policy = FALSE;
2050 rcpt_smtp_response = NULL;
2051 fl.rcpt_smtp_response_same = TRUE;
2052 fl.rcpt_in_progress = FALSE;
2053 f.deliver_freeze = FALSE; /* Can be set by ACL */
2054 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2055 fake_response = OK; /* Can be set by ACL */
2056 #ifdef WITH_CONTENT_SCAN
2057 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2059 f.submission_mode = FALSE; /* Can be set by ACL */
2060 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2061 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2062 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2063 sending_ip_address = NULL;
2064 return_path = sender_address = NULL;
2065 deliver_localpart_data = deliver_domain_data =
2066 recipient_data = sender_data = NULL; /* Can be set by ACL */
2067 recipient_verify_failure = NULL;
2068 deliver_localpart_parent = deliver_localpart_orig = NULL;
2069 deliver_domain_parent = deliver_domain_orig = NULL;
2070 callout_address = NULL;
2071 submission_name = NULL; /* Can be set by ACL */
2072 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2073 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2074 sender_verified_list = NULL; /* No senders verified */
2075 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2076 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2078 authenticated_sender = NULL;
2079 #ifdef EXPERIMENTAL_BRIGHTMAIL
2081 bmi_verdicts = NULL;
2083 dnslist_domain = dnslist_matched = NULL;
2085 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2086 spf_result_guessed = FALSE;
2088 #ifndef DISABLE_DKIM
2089 dkim_cur_signer = dkim_signers =
2090 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2091 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2092 f.dkim_disable_verify = FALSE;
2093 dkim_collect_input = 0;
2094 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2095 dkim_key_length = 0;
2097 #ifdef SUPPORT_DMARC
2098 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2099 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2100 dmarc_used_domain = NULL;
2102 #ifdef EXPERIMENTAL_ARC
2103 arc_state = arc_state_reason = NULL;
2104 arc_received_instance = 0;
2108 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2109 #ifndef DISABLE_PRDR
2110 prdr_requested = FALSE;
2113 message_smtputf8 = FALSE;
2115 body_linecount = body_zerocount = 0;
2117 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2118 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2119 /* Note that ratelimiters_conn persists across resets. */
2121 /* Reset message ACL variables */
2125 /* Warning log messages are saved in malloc store. They are saved to avoid
2126 repetition in the same message, but it seems right to repeat them for different
2129 while (acl_warn_logged)
2131 string_item *this = acl_warn_logged;
2132 acl_warn_logged = acl_warn_logged->next;
2137 store_reset(reset_point);
2140 return store_mark();
2147 /*************************************************
2148 * Initialize for incoming batched SMTP message *
2149 *************************************************/
2151 /* This function is called from smtp_setup_msg() in the case when
2152 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2153 of messages in one file with SMTP commands between them. All errors must be
2154 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2155 relevant. After an error on a sender, or an invalid recipient, the remainder
2156 of the message is skipped. The value of received_protocol is already set.
2159 Returns: > 0 message successfully started (reached DATA)
2160 = 0 QUIT read or end of file reached
2161 < 0 should not occur
2165 smtp_setup_batch_msg(void)
2168 rmark reset_point = store_mark();
2170 /* Save the line count at the start of each transaction - single commands
2171 like HELO and RSET count as whole transactions. */
2173 bsmtp_transaction_linecount = receive_linecount;
2175 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2177 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2178 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2180 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2181 value. The values are 2 larger than the required yield of the function. */
2186 uschar *recipient = NULL;
2187 int start, end, sender_domain, recipient_domain;
2189 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2191 /* The HELO/EHLO commands set sender_address_helo if they have
2192 valid data; otherwise they are ignored, except that they do
2193 a reset of the state. */
2198 check_helo(smtp_cmd_data);
2202 cancel_cutthrough_connection(TRUE, US"RSET received");
2203 reset_point = smtp_reset(reset_point);
2204 bsmtp_transaction_linecount = receive_linecount;
2208 /* The MAIL FROM command requires an address as an operand. All we
2209 do here is to parse it for syntactic correctness. The form "<>" is
2210 a special case which converts into an empty string. The start/end
2211 pointers in the original are not used further for this address, as
2212 it is the canonical extracted address which is all that is kept. */
2215 smtp_mailcmd_count++; /* Count for no-mail log */
2217 /* The function moan_smtp_batch() does not return. */
2218 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2220 if (smtp_cmd_data[0] == 0)
2221 /* The function moan_smtp_batch() does not return. */
2222 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2224 /* Reset to start of message */
2226 cancel_cutthrough_connection(TRUE, US"MAIL received");
2227 reset_point = smtp_reset(reset_point);
2229 /* Apply SMTP rewrite */
2231 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2232 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2233 US"", global_rewrite_rules) : smtp_cmd_data;
2235 /* Extract the address; the TRUE flag allows <> as valid */
2238 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2242 /* The function moan_smtp_batch() does not return. */
2243 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2245 sender_address = string_copy(raw_sender);
2247 /* Qualify unqualified sender addresses if permitted to do so. */
2250 && sender_address[0] != 0 && sender_address[0] != '@')
2251 if (f.allow_unqualified_sender)
2253 sender_address = rewrite_address_qualify(sender_address, FALSE);
2254 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2255 "and rewritten\n", raw_sender);
2257 /* The function moan_smtp_batch() does not return. */
2259 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2264 /* The RCPT TO command requires an address as an operand. All we do
2265 here is to parse it for syntactic correctness. There may be any number
2266 of RCPT TO commands, specifying multiple senders. We build them all into
2267 a data structure that is in argc/argv format. The start/end values
2268 given by parse_extract_address are not used, as we keep only the
2269 extracted address. */
2272 if (!sender_address)
2273 /* The function moan_smtp_batch() does not return. */
2274 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2276 if (smtp_cmd_data[0] == 0)
2277 /* The function moan_smtp_batch() does not return. */
2278 moan_smtp_batch(smtp_cmd_buffer,
2279 "501 RCPT TO must have an address operand");
2281 /* Check maximum number allowed */
2283 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2284 /* The function moan_smtp_batch() does not return. */
2285 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2286 recipients_max_reject? "552": "452");
2288 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2289 recipient address */
2291 recipient = rewrite_existflags & rewrite_smtp
2292 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2293 global_rewrite_rules)
2296 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2297 &recipient_domain, FALSE);
2300 /* The function moan_smtp_batch() does not return. */
2301 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2303 /* If the recipient address is unqualified, qualify it if permitted. Then
2304 add it to the list of recipients. */
2306 if (!recipient_domain)
2307 if (f.allow_unqualified_recipient)
2309 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2311 recipient = rewrite_address_qualify(recipient, TRUE);
2313 /* The function moan_smtp_batch() does not return. */
2315 moan_smtp_batch(smtp_cmd_buffer,
2316 "501 recipient address must contain a domain");
2318 receive_add_recipient(recipient, -1);
2322 /* The DATA command is legal only if it follows successful MAIL FROM
2323 and RCPT TO commands. This function is complete when a valid DATA
2324 command is encountered. */
2327 if (!sender_address || recipients_count <= 0)
2328 /* The function moan_smtp_batch() does not return. */
2329 if (!sender_address)
2330 moan_smtp_batch(smtp_cmd_buffer,
2331 "503 MAIL FROM:<sender> command must precede DATA");
2333 moan_smtp_batch(smtp_cmd_buffer,
2334 "503 RCPT TO:<recipient> must precede DATA");
2337 done = 3; /* DATA successfully achieved */
2338 message_ended = END_NOTENDED; /* Indicate in middle of message */
2343 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2350 bsmtp_transaction_linecount = receive_linecount;
2355 f.smtp_in_quit = TRUE;
2362 /* The function moan_smtp_batch() does not return. */
2363 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2368 /* The function moan_smtp_batch() does not return. */
2369 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2374 /* The function moan_smtp_batch() does not return. */
2375 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2380 return done - 2; /* Convert yield values */
2388 smtp_log_tls_fail(uschar * errstr)
2390 uschar * conn_info = smtp_get_connection_info();
2392 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2393 /* I'd like to get separated H= here, but too hard for now */
2395 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2409 socklen_t len = sizeof(is_fastopen);
2411 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2412 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2414 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2419 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2420 f.tcp_in_fastopen = TRUE;
2423 else DEBUG(D_receive)
2424 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2426 # elif defined(TCP_INFO)
2427 struct tcp_info tinfo;
2428 socklen_t len = sizeof(tinfo);
2430 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2431 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2432 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2435 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2436 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2440 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2443 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2444 f.tcp_in_fastopen = TRUE;
2446 else DEBUG(D_receive)
2447 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2453 /*************************************************
2454 * Start an SMTP session *
2455 *************************************************/
2457 /* This function is called at the start of an SMTP session. Thereafter,
2458 smtp_setup_msg() is called to initiate each separate message. This
2459 function does host-specific testing, and outputs the banner line.
2462 Returns: FALSE if the session can not continue; something has
2463 gone wrong, or the connection to the host is blocked
2467 smtp_start_session(void)
2470 uschar *user_msg, *log_msg;
2475 gettimeofday(&smtp_connection_start, NULL);
2476 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2477 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2480 /* Default values for certain variables */
2482 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2483 smtp_mailcmd_count = 0;
2484 count_nonmail = TRUE_UNSET;
2485 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2486 smtp_delay_mail = smtp_rlm_base;
2487 fl.auth_advertised = FALSE;
2488 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2489 f.pipelining_enable = TRUE;
2490 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2491 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2493 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2494 authentication settings from -oMaa to remain in force. */
2496 if (!host_checking && !f.sender_host_notsocket)
2497 sender_host_auth_pubname = sender_host_authenticated = NULL;
2498 authenticated_by = NULL;
2501 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2502 tls_in.ourcert = tls_in.peercert = NULL;
2504 tls_in.ocsp = OCSP_NOT_REQ;
2505 fl.tls_advertised = FALSE;
2507 fl.dsn_advertised = FALSE;
2509 fl.smtputf8_advertised = FALSE;
2512 /* Reset ACL connection variables */
2516 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2518 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2520 smtp_cmd_buffer[0] = 0;
2521 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2523 /* For batched input, the protocol setting can be overridden from the
2524 command line by a trusted caller. */
2526 if (smtp_batched_input)
2528 if (!received_protocol) received_protocol = US"local-bsmtp";
2531 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2532 reset later if any of EHLO/AUTH/STARTTLS are received. */
2536 (sender_host_address ? protocols : protocols_local) [pnormal];
2538 /* Set up the buffer for inputting using direct read() calls, and arrange to
2539 call the local functions instead of the standard C ones. Place a NUL at the
2540 end of the buffer to safety-stop C-string reads from it. */
2542 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2543 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2544 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2546 receive_getc = smtp_getc;
2547 receive_getbuf = smtp_getbuf;
2548 receive_get_cache = smtp_get_cache;
2549 receive_ungetc = smtp_ungetc;
2550 receive_feof = smtp_feof;
2551 receive_ferror = smtp_ferror;
2552 receive_smtp_buffered = smtp_buffered;
2553 lwr_receive_getc = lwr_receive_getbuf = lwr_receive_ungetc = NULL;
2554 smtp_inptr = smtp_inend = smtp_inbuffer;
2555 smtp_had_eof = smtp_had_error = 0;
2557 /* Set up the message size limit; this may be host-specific */
2559 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2560 if (expand_string_message)
2562 if (thismessage_size_limit == -1)
2563 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2564 "%s", expand_string_message);
2566 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2567 "%s", expand_string_message);
2568 smtp_closedown(US"Temporary local problem - please try later");
2572 /* When a message is input locally via the -bs or -bS options, sender_host_
2573 unknown is set unless -oMa was used to force an IP address, in which case it
2574 is checked like a real remote connection. When -bs is used from inetd, this
2575 flag is not set, causing the sending host to be checked. The code that deals
2576 with IP source routing (if configured) is never required for -bs or -bS and
2577 the flag sender_host_notsocket is used to suppress it.
2579 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2580 reserve for certain hosts and/or networks. */
2582 if (!f.sender_host_unknown)
2585 BOOL reserved_host = FALSE;
2587 /* Look up IP options (source routing info) on the socket if this is not an
2588 -oMa "host", and if any are found, log them and drop the connection.
2590 Linux (and others now, see below) is different to everyone else, so there
2591 has to be some conditional compilation here. Versions of Linux before 2.1.15
2592 used a structure whose name was "options". Somebody finally realized that
2593 this name was silly, and it got changed to "ip_options". I use the
2594 newer name here, but there is a fudge in the script that sets up os.h
2595 to define a macro in older Linux systems.
2597 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2598 glibc 2, which has chosen ip_opts for the structure name. This is now
2599 really a glibc thing rather than a Linux thing, so the condition name
2600 has been changed to reflect this. It is relevant also to GNU/Hurd.
2602 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2603 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2604 a special macro defined in the os.h file.
2606 Some DGUX versions on older hardware appear not to support IP options at
2607 all, so there is now a general macro which can be set to cut out this
2610 How to do this properly in IPv6 is not yet known. */
2612 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2614 #ifdef GLIBC_IP_OPTIONS
2615 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2620 #elif defined DARWIN_IP_OPTIONS
2626 if (!host_checking && !f.sender_host_notsocket)
2629 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2630 struct ip_options *ipopt = store_get(optlen, FALSE);
2632 struct ip_opts ipoptblock;
2633 struct ip_opts *ipopt = &ipoptblock;
2634 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2636 struct ipoption ipoptblock;
2637 struct ipoption *ipopt = &ipoptblock;
2638 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2641 /* Occasional genuine failures of getsockopt() have been seen - for
2642 example, "reset by peer". Therefore, just log and give up on this
2643 call, unless the error is ENOPROTOOPT. This error is given by systems
2644 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2645 of writing. So for that error, carry on - we just can't do an IP options
2648 DEBUG(D_receive) debug_printf("checking for IP options\n");
2650 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2653 if (errno != ENOPROTOOPT)
2655 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2656 host_and_ident(FALSE), strerror(errno));
2657 smtp_printf("451 SMTP service not available\r\n", FALSE);
2662 /* Deal with any IP options that are set. On the systems I have looked at,
2663 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2664 more logging data than will fit in big_buffer. Nevertheless, after somebody
2665 questioned this code, I've added in some paranoid checking. */
2667 else if (optlen > 0)
2669 uschar *p = big_buffer;
2670 uschar *pend = big_buffer + big_buffer_size;
2673 struct in_addr addr;
2676 uschar *optstart = US (ipopt->__data);
2678 uschar *optstart = US (ipopt->ip_opts);
2680 uschar *optstart = US (ipopt->ipopt_list);
2683 DEBUG(D_receive) debug_printf("IP options exist\n");
2685 Ustrcpy(p, "IP options on incoming call:");
2688 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2701 if (!string_format(p, pend-p, " %s [@%s",
2702 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2704 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2706 inet_ntoa(ipopt->ip_dst)))
2708 inet_ntoa(ipopt->ipopt_dst)))
2716 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2718 while (optcount-- > 0)
2720 memcpy(&addr, adptr, sizeof(addr));
2721 if (!string_format(p, pend - p - 1, "%s%s",
2722 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2728 adptr += sizeof(struct in_addr);
2736 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2739 for (int i = 0; i < opt[1]; i++)
2740 p += sprintf(CS p, "%2.2x ", opt[i]);
2748 log_write(0, LOG_MAIN, "%s", big_buffer);
2750 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2752 log_write(0, LOG_MAIN|LOG_REJECT,
2753 "connection from %s refused (IP options)", host_and_ident(FALSE));
2755 smtp_printf("554 SMTP service not available\r\n", FALSE);
2759 /* Length of options = 0 => there are no options */
2761 else DEBUG(D_receive) debug_printf("no IP options found\n");
2763 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2765 /* Set keep-alive in socket options. The option is on by default. This
2766 setting is an attempt to get rid of some hanging connections that stick in
2767 read() when the remote end (usually a dialup) goes away. */
2769 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2770 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2772 /* If the current host matches host_lookup, set the name by doing a
2773 reverse lookup. On failure, sender_host_name will be NULL and
2774 host_lookup_failed will be TRUE. This may or may not be serious - optional
2777 if (verify_check_host(&host_lookup) == OK)
2779 (void)host_name_lookup();
2780 host_build_sender_fullhost();
2783 /* Delay this until we have the full name, if it is looked up. */
2785 set_process_info("handling incoming connection from %s",
2786 host_and_ident(FALSE));
2788 /* Expand smtp_receive_timeout, if needed */
2790 if (smtp_receive_timeout_s)
2793 if ( !(exp = expand_string(smtp_receive_timeout_s))
2795 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2797 log_write(0, LOG_MAIN|LOG_PANIC,
2798 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2801 /* Test for explicit connection rejection */
2803 if (verify_check_host(&host_reject_connection) == OK)
2805 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2806 "from %s (host_reject_connection)", host_and_ident(FALSE));
2807 smtp_printf("554 SMTP service not available\r\n", FALSE);
2811 /* Test with TCP Wrappers if so configured. There is a problem in that
2812 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2813 such as disks dying. In these cases, it is desirable to reject with a 4xx
2814 error instead of a 5xx error. There isn't a "right" way to detect such
2815 problems. The following kludge is used: errno is zeroed before calling
2816 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2817 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2820 #ifdef USE_TCP_WRAPPERS
2822 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2823 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2824 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2825 expand_string_message);
2827 if (!hosts_ctl(tcp_wrappers_name,
2828 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2829 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2830 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2832 if (errno == 0 || errno == ENOENT)
2834 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2835 log_write(L_connection_reject,
2836 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2837 "(tcp wrappers)", host_and_ident(FALSE));
2838 smtp_printf("554 SMTP service not available\r\n", FALSE);
2842 int save_errno = errno;
2843 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2844 "errno value %d\n", save_errno);
2845 log_write(L_connection_reject,
2846 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2847 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2848 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2854 /* Check for reserved slots. The value of smtp_accept_count has already been
2855 incremented to include this process. */
2857 if (smtp_accept_max > 0 &&
2858 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2860 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2862 log_write(L_connection_reject,
2863 LOG_MAIN, "temporarily refused connection from %s: not in "
2864 "reserve list: connected=%d max=%d reserve=%d%s",
2865 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2866 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2867 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2868 "please try again later\r\n", FALSE, smtp_active_hostname);
2871 reserved_host = TRUE;
2874 /* If a load level above which only messages from reserved hosts are
2875 accepted is set, check the load. For incoming calls via the daemon, the
2876 check is done in the superior process if there are no reserved hosts, to
2877 save a fork. In all cases, the load average will already be available
2878 in a global variable at this point. */
2880 if (smtp_load_reserve >= 0 &&
2881 load_average > smtp_load_reserve &&
2883 verify_check_host(&smtp_reserve_hosts) != OK)
2885 log_write(L_connection_reject,
2886 LOG_MAIN, "temporarily refused connection from %s: not in "
2887 "reserve list and load average = %.2f", host_and_ident(FALSE),
2888 (double)load_average/1000.0);
2889 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2890 smtp_active_hostname);
2894 /* Determine whether unqualified senders or recipients are permitted
2895 for this host. Unfortunately, we have to do this every time, in order to
2896 set the flags so that they can be inspected when considering qualifying
2897 addresses in the headers. For a site that permits no qualification, this
2898 won't take long, however. */
2900 f.allow_unqualified_sender =
2901 verify_check_host(&sender_unqualified_hosts) == OK;
2903 f.allow_unqualified_recipient =
2904 verify_check_host(&recipient_unqualified_hosts) == OK;
2906 /* Determine whether HELO/EHLO is required for this host. The requirement
2907 can be hard or soft. */
2909 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2910 if (!fl.helo_required)
2911 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2913 /* Determine whether this hosts is permitted to send syntactic junk
2914 after a HELO or EHLO command. */
2916 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2919 /* For batch SMTP input we are now done. */
2921 if (smtp_batched_input) return TRUE;
2923 /* If valid Proxy Protocol source is connecting, set up session.
2924 Failure will not allow any SMTP function other than QUIT. */
2926 #ifdef SUPPORT_PROXY
2927 proxy_session = FALSE;
2928 f.proxy_session_failed = FALSE;
2929 if (check_proxy_protocol_host())
2930 setup_proxy_protocol_host();
2933 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2934 smtps port for use with older style SSL MTAs. */
2937 if (tls_in.on_connect)
2939 if (tls_server_start(&user_msg) != OK)
2940 return smtp_log_tls_fail(user_msg);
2941 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2945 /* Run the connect ACL if it exists */
2948 if (acl_smtp_connect)
2951 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2954 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2959 /* Output the initial message for a two-way SMTP connection. It may contain
2960 newlines, which then cause a multi-line response to be given. */
2962 code = US"220"; /* Default status code */
2963 esc = US""; /* Default extended status code */
2964 esclen = 0; /* Length of esc */
2968 if (!(s = expand_string(smtp_banner)))
2969 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2970 "failed: %s", smtp_banner, expand_string_message);
2976 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2980 esclen = codelen - 4;
2984 /* Remove any terminating newlines; might as well remove trailing space too */
2987 while (p > s && isspace(p[-1])) p--;
2990 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2991 is all contained in a single IP packet. The original code wrote out the
2992 greeting using several calls to fprint/fputc, and on busy servers this could
2993 cause it to be split over more than one packet - which caused CC:Mail to fall
2994 over when it got the second part of the greeting after sending its first
2995 command. Sigh. To try to avoid this, build the complete greeting message
2996 first, and output it in one fell swoop. This gives a better chance of it
2997 ending up as a single packet. */
2999 ss = string_get(256);
3002 do /* At least once, in case we have an empty string */
3005 uschar *linebreak = Ustrchr(p, '\n');
3006 ss = string_catn(ss, code, 3);
3010 ss = string_catn(ss, US" ", 1);
3014 len = linebreak - p;
3015 ss = string_catn(ss, US"-", 1);
3017 ss = string_catn(ss, esc, esclen);
3018 ss = string_catn(ss, p, len);
3019 ss = string_catn(ss, US"\r\n", 2);
3025 /* Before we write the banner, check that there is no input pending, unless
3026 this synchronisation check is disabled. */
3028 #ifndef DISABLE_PIPE_CONNECT
3029 fl.pipe_connect_acceptable =
3030 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3033 if (fl.pipe_connect_acceptable)
3034 f.smtp_in_early_pipe_used = TRUE;
3040 unsigned n = smtp_inend - smtp_inptr;
3041 if (n > 128) n = 128;
3043 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3044 "synchronization error (input sent without waiting for greeting): "
3045 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3046 string_printing(string_copyn(smtp_inptr, n)));
3047 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3051 /* Now output the banner */
3052 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3055 #ifndef DISABLE_PIPE_CONNECT
3056 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3060 string_from_gstring(ss));
3062 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3063 handshake arrived. If so we must have managed a TFO. */
3066 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3076 /*************************************************
3077 * Handle SMTP syntax and protocol errors *
3078 *************************************************/
3080 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3081 to do so. Then transmit the error response. The return value depends on the
3082 number of syntax and protocol errors in this SMTP session.
3085 type error type, given as a log flag bit
3086 code response code; <= 0 means don't send a response
3087 data data to reflect in the response (can be NULL)
3088 errmess the error message
3090 Returns: -1 limit of syntax/protocol errors NOT exceeded
3091 +1 limit of syntax/protocol errors IS exceeded
3093 These values fit in with the values of the "done" variable in the main
3094 processing loop in smtp_setup_msg(). */
3097 synprot_error(int type, int code, uschar *data, uschar *errmess)
3101 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3102 type == L_smtp_syntax_error ? "syntax" : "protocol",
3103 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3105 if (++synprot_error_count > smtp_max_synprot_errors)
3108 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3109 "syntax or protocol errors (last command was \"%s\", %s)",
3110 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3111 string_from_gstring(s_connhad_log(NULL))
3117 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3118 data ? data : US"", data ? US": " : US"", errmess);
3120 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3129 /*************************************************
3130 * Send SMTP response, possibly multiline *
3131 *************************************************/
3133 /* There are, it seems, broken clients out there that cannot handle multiline
3134 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3135 output nothing for non-final calls, and only the first line for anything else.
3138 code SMTP code, may involve extended status codes
3139 codelen length of smtp code; if > 4 there's an ESC
3140 final FALSE if the last line isn't the final line
3141 msg message text, possibly containing newlines
3147 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3152 if (!final && f.no_multiline_responses) return;
3157 esclen = codelen - 4;
3160 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3161 have had the same. Note: this code is also present in smtp_printf(). It would
3162 be tidier to have it only in one place, but when it was added, it was easier to
3163 do it that way, so as not to have to mess with the code for the RCPT command,
3164 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3166 if (fl.rcpt_in_progress)
3168 if (rcpt_smtp_response == NULL)
3169 rcpt_smtp_response = string_copy(msg);
3170 else if (fl.rcpt_smtp_response_same &&
3171 Ustrcmp(rcpt_smtp_response, msg) != 0)
3172 fl.rcpt_smtp_response_same = FALSE;
3173 fl.rcpt_in_progress = FALSE;
3176 /* Now output the message, splitting it up into multiple lines if necessary.
3177 We only handle pipelining these responses as far as nonfinal/final groups,
3178 not the whole MAIL/RCPT/DATA response set. */
3182 uschar *nl = Ustrchr(msg, '\n');
3185 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3188 else if (nl[1] == 0 || f.no_multiline_responses)
3190 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3191 (int)(nl - msg), msg);
3196 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3198 Uskip_whitespace(&msg);
3206 /*************************************************
3207 * Parse user SMTP message *
3208 *************************************************/
3210 /* This function allows for user messages overriding the response code details
3211 by providing a suitable response code string at the start of the message
3212 user_msg. Check the message for starting with a response code and optionally an
3213 extended status code. If found, check that the first digit is valid, and if so,
3214 change the code pointer and length to use the replacement. An invalid code
3215 causes a panic log; in this case, if the log messages is the same as the user
3216 message, we must also adjust the value of the log message to show the code that
3217 is actually going to be used (the original one).
3219 This function is global because it is called from receive.c as well as within
3222 Note that the code length returned includes the terminating whitespace
3223 character, which is always included in the regex match.
3226 code SMTP code, may involve extended status codes
3227 codelen length of smtp code; if > 4 there's an ESC
3229 log_msg optional log message, to be adjusted with the new SMTP code
3230 check_valid if true, verify the response code
3236 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3242 if (!msg || !*msg) return;
3244 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3245 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3247 if (check_valid && (*msg)[0] != (*code)[0])
3249 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3250 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3251 if (log_msg != NULL && *log_msg == *msg)
3252 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3257 *codelen = ovector[1]; /* Includes final space */
3259 *msg += ovector[1]; /* Chop the code off the message */
3266 /*************************************************
3267 * Handle an ACL failure *
3268 *************************************************/
3270 /* This function is called when acl_check() fails. As well as calls from within
3271 this module, it is called from receive.c for an ACL after DATA. It sorts out
3272 logging the incident, and sends the error response. A message containing
3273 newlines is turned into a multiline SMTP response, but for logging, only the
3276 There's a table of default permanent failure response codes to use in
3277 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3278 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3279 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3280 state, because there are broken clients that try VRFY before RCPT. A 5xx
3281 response should be given only when the address is positively known to be
3282 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3283 no explicit code, but if there is one we let it know best.
3284 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3286 From Exim 4.63, it is possible to override the response code details by
3287 providing a suitable response code string at the start of the message provided
3288 in user_msg. The code's first digit is checked for validity.
3291 where where the ACL was called from
3293 user_msg a message that can be included in an SMTP response
3294 log_msg a message for logging
3296 Returns: 0 in most cases
3297 2 if the failure code was FAIL_DROP, in which case the
3298 SMTP connection should be dropped (this value fits with the
3299 "done" variable in smtp_setup_msg() below)
3303 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3305 BOOL drop = rc == FAIL_DROP;
3309 uschar *sender_info = US"";
3312 if (drop) rc = FAIL;
3314 /* Set the default SMTP code, and allow a user message to change it. */
3316 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3317 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3318 where != ACL_WHERE_VRFY);
3320 /* We used to have sender_address here; however, there was a bug that was not
3321 updating sender_address after a rewrite during a verify. When this bug was
3322 fixed, sender_address at this point became the rewritten address. I'm not sure
3323 this is what should be logged, so I've changed to logging the unrewritten
3324 address to retain backward compatibility. */
3328 #ifdef WITH_CONTENT_SCAN
3329 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3331 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3332 case ACL_WHERE_DATA: what = US"after DATA"; break;
3333 #ifndef DISABLE_PRDR
3334 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3338 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3341 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3344 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
3345 lim = s - smtp_cmd_data; /* atop after method */
3347 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3352 case ACL_WHERE_RCPT:
3353 case ACL_WHERE_DATA:
3354 #ifdef WITH_CONTENT_SCAN
3355 case 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""
3367 /* If there's been a sender verification failure with a specific message, and
3368 we have not sent a response about it yet, do so now, as a preliminary line for
3369 failures, but not defers. However, always log it for defer, and log it for fail
3370 unless the sender_verify_fail log selector has been turned off. */
3372 if (sender_verified_failed &&
3373 !testflag(sender_verified_failed, af_sverify_told))
3375 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3376 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3378 setflag(sender_verified_failed, af_sverify_told);
3380 if (rc != FAIL || LOGGING(sender_verify_fail))
3381 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3382 host_and_ident(TRUE),
3383 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3384 sender_verified_failed->address,
3385 (sender_verified_failed->message == NULL)? US"" :
3386 string_sprintf(": %s", sender_verified_failed->message));
3388 if (rc == FAIL && sender_verified_failed->user_message)
3389 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3390 testflag(sender_verified_failed, af_verify_pmfail)?
3391 "Postmaster verification failed while checking <%s>\n%s\n"
3392 "Several RFCs state that you are required to have a postmaster\n"
3393 "mailbox for each mail domain. This host does not accept mail\n"
3394 "from domains whose servers reject the postmaster address."
3396 testflag(sender_verified_failed, af_verify_nsfail)?
3397 "Callback setup failed while verifying <%s>\n%s\n"
3398 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3399 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3400 "RFC requirements, and stops you from receiving standard bounce\n"
3401 "messages. This host does not accept mail from domains whose servers\n"
3404 "Verification failed for <%s>\n%s",
3405 sender_verified_failed->address,
3406 sender_verified_failed->user_message));
3408 fl.rcpt_in_progress = save_rcpt_in_progress;
3411 /* Sort out text for logging */
3413 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3414 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3416 /* Send permanent failure response to the command, but the code used isn't
3417 always a 5xx one - see comments at the start of this function. If the original
3418 rc was FAIL_DROP we drop the connection and yield 2. */
3421 smtp_respond(smtp_code, codelen, TRUE,
3422 user_msg ? user_msg : US"Administrative prohibition");
3424 /* Send temporary failure response to the command. Don't give any details,
3425 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3426 verb, and for a header verify when smtp_return_error_details is set.
3428 This conditional logic is all somewhat of a mess because of the odd
3429 interactions between temp_details and return_error_details. One day it should
3430 be re-implemented in a tidier fashion. */
3433 if (f.acl_temp_details && user_msg)
3435 if ( smtp_return_error_details
3436 && sender_verified_failed
3437 && sender_verified_failed->message
3439 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3441 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3444 smtp_respond(smtp_code, codelen, TRUE,
3445 US"Temporary local problem - please try later");
3447 /* Log the incident to the logs that are specified by log_reject_target
3448 (default main, reject). This can be empty to suppress logging of rejections. If
3449 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3450 is closing if required and return 2. */
3452 if (log_reject_target != 0)
3455 gstring * g = s_tlslog(NULL);
3456 uschar * tls = string_from_gstring(g);
3457 if (!tls) tls = US"";
3459 uschar * tls = US"";
3461 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3462 log_reject_target, "%s%s%s %s%srejected %s%s",
3463 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3464 host_and_ident(TRUE),
3467 rc == FAIL ? US"" : US"temporarily ",
3471 if (!drop) return 0;
3473 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3474 smtp_get_connection_info());
3476 /* Run the not-quit ACL, but without any custom messages. This should not be a
3477 problem, because we get here only if some other ACL has issued "drop", and
3478 in that case, *its* custom messages will have been used above. */
3480 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3487 /*************************************************
3488 * Handle SMTP exit when QUIT is not given *
3489 *************************************************/
3491 /* This function provides a logging/statistics hook for when an SMTP connection
3492 is dropped on the floor or the other end goes away. It's a global function
3493 because it's called from receive.c as well as this module. As well as running
3494 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3495 response, either with a custom message from the ACL, or using a default. There
3496 is one case, however, when no message is output - after "drop". In that case,
3497 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3498 passed to this function.
3500 In case things go wrong while processing this function, causing an error that
3501 may re-enter this function, there is a recursion check.
3504 reason What $smtp_notquit_reason will be set to in the ACL;
3505 if NULL, the ACL is not run
3506 code The error code to return as part of the response
3507 defaultrespond The default message if there's no user_msg
3513 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3516 uschar *user_msg = NULL;
3517 uschar *log_msg = NULL;
3519 /* Check for recursive call */
3521 if (fl.smtp_exit_function_called)
3523 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3527 fl.smtp_exit_function_called = TRUE;
3529 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3531 if (acl_smtp_notquit && reason)
3533 smtp_notquit_reason = reason;
3534 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3535 &log_msg)) == ERROR)
3536 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3540 /* If the connection was dropped, we certainly are no longer talking TLS */
3541 tls_in.active.sock = -1;
3543 /* Write an SMTP response if we are expected to give one. As the default
3544 responses are all internal, they should be reasonable size. */
3546 if (code && defaultrespond)
3549 smtp_respond(code, 3, TRUE, user_msg);
3555 va_start(ap, defaultrespond);
3556 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3558 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3567 /*************************************************
3568 * Verify HELO argument *
3569 *************************************************/
3571 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3572 matched. It is also called from ACL processing if verify = helo is used and
3573 verification was not previously tried (i.e. helo_try_verify_hosts was not
3574 matched). The result of its processing is to set helo_verified and
3575 helo_verify_failed. These variables should both be FALSE for this function to
3578 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3579 for IPv6 ::ffff: literals.
3582 Returns: TRUE if testing was completed;
3583 FALSE on a temporary failure
3587 smtp_verify_helo(void)
3591 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3594 if (sender_helo_name == NULL)
3596 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3599 /* Deal with the case of -bs without an IP address */
3601 else if (sender_host_address == NULL)
3603 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3604 f.helo_verified = TRUE;
3607 /* Deal with the more common case when there is a sending IP address */
3609 else if (sender_helo_name[0] == '[')
3611 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3612 Ustrlen(sender_host_address)) == 0;
3615 if (!f.helo_verified)
3617 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3618 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3619 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3624 { if (f.helo_verified) debug_printf("matched host address\n"); }
3627 /* Do a reverse lookup if one hasn't already given a positive or negative
3628 response. If that fails, or the name doesn't match, try checking with a forward
3633 if (sender_host_name == NULL && !host_lookup_failed)
3634 yield = host_name_lookup() != DEFER;
3636 /* If a host name is known, check it and all its aliases. */
3638 if (sender_host_name)
3639 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3641 sender_helo_dnssec = sender_host_dnssec;
3642 HDEBUG(D_receive) debug_printf("matched host name\n");
3646 uschar **aliases = sender_host_aliases;
3648 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3650 sender_helo_dnssec = sender_host_dnssec;
3654 HDEBUG(D_receive) if (f.helo_verified)
3655 debug_printf("matched alias %s\n", *(--aliases));
3658 /* Final attempt: try a forward lookup of the helo name */
3660 if (!f.helo_verified)
3664 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3666 {.request = US"*", .require = US""};
3668 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3670 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3671 NULL, NULL, NULL, &d, NULL, NULL);
3672 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3673 for (host_item * hh = &h; hh; hh = hh->next)
3674 if (Ustrcmp(hh->address, sender_host_address) == 0)
3676 f.helo_verified = TRUE;
3677 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3679 debug_printf("IP address for %s matches calling address\n"
3680 "Forward DNS security status: %sverified\n",
3681 sender_helo_name, sender_helo_dnssec ? "" : "un");
3687 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3694 /*************************************************
3695 * Send user response message *
3696 *************************************************/
3698 /* This function is passed a default response code and a user message. It calls
3699 smtp_message_code() to check and possibly modify the response code, and then
3700 calls smtp_respond() to transmit the response. I put this into a function
3701 just to avoid a lot of repetition.
3704 code the response code
3705 user_msg the user message
3711 smtp_user_msg(uschar *code, uschar *user_msg)
3714 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3715 smtp_respond(code, len, TRUE, user_msg);
3721 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3723 const uschar *set_id = NULL;
3726 /* Run the checking code, passing the remainder of the command line as
3727 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3728 it as the only set numerical variable. The authenticator may set $auth<n>
3729 and also set other numeric variables. The $auth<n> variables are preferred
3730 nowadays; the numerical variables remain for backwards compatibility.
3732 Afterwards, have a go at expanding the set_id string, even if
3733 authentication failed - for bad passwords it can be useful to log the
3734 userid. On success, require set_id to expand and exist, and put it in
3735 authenticated_id. Save this in permanent store, as the working store gets
3736 reset at HELO, RSET, etc. */
3738 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3740 expand_nlength[0] = 0; /* $0 contains nothing */
3742 rc = (au->info->servercode)(au, smtp_cmd_data);
3743 if (au->set_id) set_id = expand_string(au->set_id);
3744 expand_nmax = -1; /* Reset numeric variables */
3745 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3747 /* The value of authenticated_id is stored in the spool file and printed in
3748 log lines. It must not contain binary zeros or newline characters. In
3749 normal use, it never will, but when playing around or testing, this error
3750 can (did) happen. To guard against this, ensure that the id contains only
3751 printing characters. */
3753 if (set_id) set_id = string_printing(set_id);
3755 /* For the non-OK cases, set up additional logging data if set_id
3759 set_id = set_id && *set_id
3760 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3762 /* Switch on the result */
3767 if (!au->set_id || set_id) /* Complete success */
3769 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3770 sender_host_authenticated = au->name;
3771 sender_host_auth_pubname = au->public_name;
3772 authentication_failed = FALSE;
3773 authenticated_fail_id = NULL; /* Impossible to already be set? */
3776 (sender_host_address ? protocols : protocols_local)
3777 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3778 *s = *ss = US"235 Authentication succeeded";
3779 authenticated_by = au;
3783 /* Authentication succeeded, but we failed to expand the set_id string.
3784 Treat this as a temporary error. */
3786 auth_defer_msg = expand_string_message;
3790 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3791 *s = string_sprintf("435 Unable to authenticate at present%s",
3792 auth_defer_user_msg);
3793 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3794 set_id, auth_defer_msg);
3798 *s = *ss = US"501 Invalid base64 data";
3802 *s = *ss = US"501 Authentication cancelled";
3806 *s = *ss = US"553 Initial data not expected";
3810 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3811 *s = US"535 Incorrect authentication data";
3812 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3816 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3817 *s = US"435 Internal error";
3818 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3819 "check", set_id, rc);
3831 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3834 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3836 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3838 rd = Ustrlen(recipient) + 1;
3839 *recipient = rewrite_address_qualify(*recipient, TRUE);
3842 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3844 log_write(L_smtp_syntax_error,
3845 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3846 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3854 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3857 f.smtp_in_quit = TRUE;
3858 incomplete_transaction_log(US"QUIT");
3860 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3862 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3865 #ifdef EXIM_TCP_CORK
3866 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_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);
3874 #ifdef SERVERSIDE_CLOSE_NOWAIT
3875 # ifndef DISABLE_TLS
3876 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3879 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3880 smtp_get_connection_info());
3883 # ifndef DISABLE_TLS
3884 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3887 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3888 smtp_get_connection_info());
3890 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3891 The socket should become readble (though with no data) */
3894 int fd = fileno(smtp_in);
3896 struct timeval t_limit = {.tv_sec = 0, .tv_usec = 200*1000};
3900 (void) select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &t_limit);
3902 #endif /*!DAEMON_CLOSE_NOWAIT*/
3907 smtp_rset_handler(void)
3910 incomplete_transaction_log(US"RSET");
3911 smtp_printf("250 Reset OK\r\n", FALSE);
3912 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3917 expand_mailmax(const uschar * s)
3919 if (!(s = expand_cstring(s)))
3920 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3921 return *s ? Uatoi(s) : 0;
3924 /*************************************************
3925 * Initialize for SMTP incoming message *
3926 *************************************************/
3928 /* This function conducts the initial dialogue at the start of an incoming SMTP
3929 message, and builds a list of recipients. However, if the incoming message
3930 is part of a batch (-bS option) a separate function is called since it would
3931 be messy having tests splattered about all over this function. This function
3932 therefore handles the case where interaction is occurring. The input and output
3933 files are set up in smtp_in and smtp_out.
3935 The global recipients_list is set to point to a vector of recipient_item
3936 blocks, whose number is given by recipients_count. This is extended by the
3937 receive_add_recipient() function. The global variable sender_address is set to
3938 the sender's address. The yield is +1 if a message has been successfully
3939 started, 0 if a QUIT command was encountered or the connection was refused from
3940 the particular host, or -1 if the connection was lost.
3944 Returns: > 0 message successfully started (reached DATA)
3945 = 0 QUIT read or end of file reached or call refused
3950 smtp_setup_msg(void)
3954 BOOL toomany = FALSE;
3955 BOOL discarded = FALSE;
3956 BOOL last_was_rej_mail = FALSE;
3957 BOOL last_was_rcpt = FALSE;
3958 rmark reset_point = store_mark();
3960 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3962 /* Reset for start of new message. We allow one RSET not to be counted as a
3963 nonmail command, for those MTAs that insist on sending it between every
3964 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3965 TLS between messages (an Exim client may do this if it has messages queued up
3966 for the host). Note: we do NOT reset AUTH at this point. */
3968 reset_point = smtp_reset(reset_point);
3969 message_ended = END_NOTSTARTED;
3971 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3973 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3974 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3975 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3977 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3980 if (lwr_receive_getc != NULL)
3982 /* This should have already happened, but if we've gotten confused,
3983 force a reset here. */
3984 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
3985 bdat_pop_receive_functions();
3988 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3990 had_command_sigterm = 0;
3991 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3993 /* Batched SMTP is handled in a different function. */
3995 if (smtp_batched_input) return smtp_setup_batch_msg();
3998 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3999 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4000 US &off, sizeof(off));
4003 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4004 value. The values are 2 larger than the required yield of the function. */
4008 const uschar **argv;
4009 uschar *etrn_command;
4010 uschar *etrn_serialize_key;
4012 uschar *log_msg, *smtp_code;
4013 uschar *user_msg = NULL;
4014 uschar *recipient = NULL;
4015 uschar *hello = NULL;
4017 BOOL was_rej_mail = FALSE;
4018 BOOL was_rcpt = FALSE;
4019 void (*oldsignal)(int);
4021 int start, end, sender_domain, recipient_domain;
4024 uschar *orcpt = NULL;
4029 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4030 if ( tls_in.active.sock >= 0
4032 && tls_in.certificate_verified
4033 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4036 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4038 for (auth_instance * au = auths; au; au = au->next)
4039 if (strcmpic(US"tls", au->driver_name) == 0)
4042 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4043 &user_msg, &log_msg)) != OK
4045 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4048 smtp_cmd_data = NULL;
4050 if (smtp_in_auth(au, &s, &ss) == OK)
4051 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4053 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4060 switch(smtp_read_command(
4061 #ifndef DISABLE_PIPE_CONNECT
4062 !fl.pipe_connect_acceptable,
4066 GETC_BUFFER_UNLIMITED))
4068 /* The AUTH command is not permitted to occur inside a transaction, and may
4069 occur successfully only once per connection. Actually, that isn't quite
4070 true. When TLS is started, all previous information about a connection must
4071 be discarded, so a new AUTH is permitted at that time.
4073 AUTH may only be used when it has been advertised. However, it seems that
4074 there are clients that send AUTH when it hasn't been advertised, some of
4075 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4076 So there's a get-out that allows this to happen.
4078 AUTH is initially labelled as a "nonmail command" so that one occurrence
4079 doesn't get counted. We change the label here so that multiple failing
4080 AUTHS will eventually hit the nonmail threshold. */
4084 authentication_failed = TRUE;
4085 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4087 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4089 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4090 US"AUTH command used when not advertised");
4093 if (sender_host_authenticated)
4095 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4096 US"already authenticated");
4101 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4102 US"not permitted in mail transaction");
4109 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4110 &user_msg, &log_msg)) != OK
4113 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4117 /* Find the name of the requested authentication mechanism. */
4120 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
4121 if (!isalnum(c) && c != '-' && c != '_')
4123 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4124 US"invalid character in authentication mechanism name");
4128 /* If not at the end of the line, we must be at white space. Terminate the
4129 name and move the pointer on to any data that may be present. */
4133 *smtp_cmd_data++ = 0;
4134 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4137 /* Search for an authentication mechanism which is configured for use
4138 as a server and which has been advertised (unless, sigh, allow_auth_
4139 unadvertised is set). */
4143 for (au = auths; au; au = au->next)
4144 if (strcmpic(s, au->public_name) == 0 && au->server &&
4145 (au->advertised || f.allow_auth_unadvertised))
4150 c = smtp_in_auth(au, &s, &ss);
4152 smtp_printf("%s\r\n", FALSE, s);
4154 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4155 au->name, host_and_ident(FALSE), ss);
4158 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4159 string_sprintf("%s authentication mechanism not supported", s));
4162 break; /* AUTH_CMD */
4164 /* The HELO/EHLO commands are permitted to appear in the middle of a
4165 session as well as at the beginning. They have the effect of a reset in
4166 addition to their other functions. Their absence at the start cannot be
4167 taken to be an error.
4171 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4172 or 502 failure replies MUST be returned as appropriate. The SMTP
4173 server MUST stay in the same state after transmitting these replies
4174 that it was in before the EHLO was received.
4176 Therefore, we do not do the reset until after checking the command for
4177 acceptability. This change was made for Exim release 4.11. Previously
4178 it did the reset first. */
4191 HELO_EHLO: /* Common code for HELO and EHLO */
4192 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4193 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4195 /* Reject the HELO if its argument was invalid or non-existent. A
4196 successful check causes the argument to be saved in malloc store. */
4198 if (!check_helo(smtp_cmd_data))
4200 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4202 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4203 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4204 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4205 string_printing(smtp_cmd_argument));
4207 if (++synprot_error_count > smtp_max_synprot_errors)
4209 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4210 "syntax or protocol errors (last command was \"%s\", %s)",
4211 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4212 string_from_gstring(s_connhad_log(NULL))
4220 /* If sender_host_unknown is true, we have got here via the -bs interface,
4221 not called from inetd. Otherwise, we are running an IP connection and the
4222 host address will be set. If the helo name is the primary name of this
4223 host and we haven't done a reverse lookup, force one now. If helo_required
4224 is set, ensure that the HELO name matches the actual host. If helo_verify
4225 is set, do the same check, but softly. */
4227 if (!f.sender_host_unknown)
4229 BOOL old_helo_verified = f.helo_verified;
4230 uschar *p = smtp_cmd_data;
4232 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4235 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4236 because otherwise the log can be confusing. */
4238 if ( !sender_host_name
4239 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4240 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4241 (void)host_name_lookup();
4243 /* Rebuild the fullhost info to include the HELO name (and the real name
4244 if it was looked up.) */
4246 host_build_sender_fullhost(); /* Rebuild */
4247 set_process_info("handling%s incoming connection from %s",
4248 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4250 /* Verify if configured. This doesn't give much security, but it does
4251 make some people happy to be able to do it. If helo_required is set,
4252 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4253 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4254 now obsolescent, since the verification can now be requested selectively
4257 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4258 if (fl.helo_required || fl.helo_verify)
4260 BOOL tempfail = !smtp_verify_helo();
4261 if (!f.helo_verified)
4263 if (fl.helo_required)
4265 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4266 tempfail? 451 : 550, hello);
4267 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4268 tempfail? "temporarily " : "",
4269 hello, sender_helo_name, host_and_ident(FALSE));
4270 f.helo_verified = old_helo_verified;
4271 break; /* End of HELO/EHLO processing */
4273 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4274 "helo_try_verify_hosts\n", hello);
4280 /* set up SPF context */
4281 spf_conn_init(sender_helo_name, sender_host_address);
4284 /* Apply an ACL check if one is defined; afterwards, recheck
4285 synchronization in case the client started sending in a delay. */
4288 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4289 &user_msg, &log_msg)) != OK)
4291 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4292 sender_helo_name = NULL;
4293 host_build_sender_fullhost(); /* Rebuild */
4296 #ifndef DISABLE_PIPE_CONNECT
4297 else if (!fl.pipe_connect_acceptable && !check_sync())
4299 else if (!check_sync())
4303 /* Generate an OK reply. The default string includes the ident if present,
4304 and also the IP address if present. Reflecting back the ident is intended
4305 as a deterrent to mail forgers. For maximum efficiency, and also because
4306 some broken systems expect each response to be in a single packet, arrange
4307 that the entire reply is sent in one write(). */
4309 fl.auth_advertised = FALSE;
4310 f.smtp_in_pipelining_advertised = FALSE;
4312 fl.tls_advertised = FALSE;
4314 fl.dsn_advertised = FALSE;
4316 fl.smtputf8_advertised = FALSE;
4319 /* Expand the per-connection message count limit option */
4320 mailmax = expand_mailmax(smtp_accept_max_per_connection);
4322 smtp_code = US"250 "; /* Default response code plus space*/
4325 /* sender_host_name below will be tainted, so save on copy when we hit it */
4326 g = string_get_tainted(24, TRUE);
4327 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4329 smtp_active_hostname,
4330 sender_ident ? sender_ident : US"",
4331 sender_ident ? US" at " : US"",
4332 sender_host_name ? sender_host_name : sender_helo_name);
4334 if (sender_host_address)
4335 g = string_fmt_append(g, " [%s]", sender_host_address);
4338 /* A user-supplied EHLO greeting may not contain more than one line. Note
4339 that the code returned by smtp_message_code() includes the terminating
4340 whitespace character. */
4346 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4347 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4348 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4350 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4351 "newlines: message truncated: %s", string_printing(s));
4354 g = string_cat(NULL, s);
4357 g = string_catn(g, US"\r\n", 2);
4359 /* If we received EHLO, we must create a multiline response which includes
4360 the functions supported. */
4366 /* I'm not entirely happy with this, as an MTA is supposed to check
4367 that it has enough room to accept a message of maximum size before
4368 it sends this. However, there seems little point in not sending it.
4369 The actual size check happens later at MAIL FROM time. By postponing it
4370 till then, VRFY and EXPN can be used after EHLO when space is short. */
4372 if (thismessage_size_limit > 0)
4373 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4374 thismessage_size_limit);
4377 g = string_catn(g, smtp_code, 3);
4378 g = string_catn(g, US"-SIZE\r\n", 7);
4381 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4382 if ( (mailmax > 0 || recipients_max)
4383 && verify_check_host(&limits_advertise_hosts) == OK)
4385 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4387 g = string_fmt_append(g, " MAILMAX=%d", mailmax);
4389 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4390 g = string_catn(g, US"\r\n", 2);
4394 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4395 clean; if it has an 8-bit character in its hand, it just sends it. It
4396 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4397 However, some users want this option simply in order to stop MUAs
4398 mangling messages that contain top-bit-set characters. It is therefore
4399 provided as an option. */
4401 if (accept_8bitmime)
4403 g = string_catn(g, smtp_code, 3);
4404 g = string_catn(g, US"-8BITMIME\r\n", 11);
4407 /* Advertise DSN support if configured to do so. */
4408 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4410 g = string_catn(g, smtp_code, 3);
4411 g = string_catn(g, US"-DSN\r\n", 6);
4412 fl.dsn_advertised = TRUE;
4415 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4416 permitted to issue them; a check is made when any host actually tries. */
4420 g = string_catn(g, smtp_code, 3);
4421 g = string_catn(g, US"-ETRN\r\n", 7);
4425 g = string_catn(g, smtp_code, 3);
4426 g = string_catn(g, US"-VRFY\r\n", 7);
4430 g = string_catn(g, smtp_code, 3);
4431 g = string_catn(g, US"-EXPN\r\n", 7);
4434 /* Exim is quite happy with pipelining, so let the other end know that
4435 it is safe to use it, unless advertising is disabled. */
4437 if ( f.pipelining_enable
4438 && verify_check_host(&pipelining_advertise_hosts) == OK)
4440 g = string_catn(g, smtp_code, 3);
4441 g = string_catn(g, US"-PIPELINING\r\n", 13);
4442 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4443 f.smtp_in_pipelining_advertised = TRUE;
4445 #ifndef DISABLE_PIPE_CONNECT
4446 if (fl.pipe_connect_acceptable)
4448 f.smtp_in_early_pipe_advertised = TRUE;
4449 g = string_catn(g, smtp_code, 3);
4450 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4456 /* If any server authentication mechanisms are configured, advertise
4457 them if the current host is in auth_advertise_hosts. The problem with
4458 advertising always is that some clients then require users to
4459 authenticate (and aren't configurable otherwise) even though it may not
4460 be necessary (e.g. if the host is in host_accept_relay).
4462 RFC 2222 states that SASL mechanism names contain only upper case
4463 letters, so output the names in upper case, though we actually recognize
4464 them in either case in the AUTH command. */
4468 && !sender_host_authenticated
4470 && verify_check_host(&auth_advertise_hosts) == OK
4474 for (auth_instance * au = auths; au; au = au->next)
4476 au->advertised = FALSE;
4479 DEBUG(D_auth+D_expand) debug_printf_indent(
4480 "Evaluating advertise_condition for %s %s athenticator\n",
4481 au->name, au->public_name);
4482 if ( !au->advertise_condition
4483 || expand_check_condition(au->advertise_condition, au->name,
4490 g = string_catn(g, smtp_code, 3);
4491 g = string_catn(g, US"-AUTH", 5);
4493 fl.auth_advertised = TRUE;
4496 g = string_catn(g, US" ", 1);
4497 g = string_cat (g, au->public_name);
4498 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4499 au->advertised = TRUE;
4504 if (!first) g = string_catn(g, US"\r\n", 2);
4507 /* RFC 3030 CHUNKING */
4509 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4511 g = string_catn(g, smtp_code, 3);
4512 g = string_catn(g, US"-CHUNKING\r\n", 11);
4513 f.chunking_offered = TRUE;
4514 chunking_state = CHUNKING_OFFERED;
4517 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4518 if it has been included in the binary, and the host matches
4519 tls_advertise_hosts. We must *not* advertise if we are already in a
4520 secure connection. */
4523 if (tls_in.active.sock < 0 &&
4524 verify_check_host(&tls_advertise_hosts) != FAIL)
4526 g = string_catn(g, smtp_code, 3);
4527 g = string_catn(g, US"-STARTTLS\r\n", 11);
4528 fl.tls_advertised = TRUE;
4532 #ifndef DISABLE_PRDR
4533 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4536 g = string_catn(g, smtp_code, 3);
4537 g = string_catn(g, US"-PRDR\r\n", 7);
4542 if ( accept_8bitmime
4543 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4545 g = string_catn(g, smtp_code, 3);
4546 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4547 fl.smtputf8_advertised = TRUE;
4551 /* Finish off the multiline reply with one that is always available. */
4553 g = string_catn(g, smtp_code, 3);
4554 g = string_catn(g, US" HELP\r\n", 7);
4557 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4561 if (tls_in.active.sock >= 0)
4562 (void)tls_write(NULL, g->s, g->ptr,
4563 # ifndef DISABLE_PIPE_CONNECT
4564 fl.pipe_connect_acceptable && pipeline_connect_sends());
4570 (void) fwrite(g->s, 1, g->ptr, smtp_out);
4576 (void) string_from_gstring(g);
4577 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4578 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4579 debug_printf("SMTP>> %s", g->s);
4581 fl.helo_seen = TRUE;
4583 /* Reset the protocol and the state, abandoning any previous message. */
4585 (sender_host_address ? protocols : protocols_local)
4587 ? pextend + (sender_host_authenticated ? pauthed : 0)
4589 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4591 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4592 reset_point = smtp_reset(reset_point);
4594 break; /* HELO/EHLO */
4597 /* The MAIL command requires an address as an operand. All we do
4598 here is to parse it for syntactic correctness. The form "<>" is
4599 a special case which converts into an empty string. The start/end
4600 pointers in the original are not used further for this address, as
4601 it is the canonical extracted address which is all that is kept. */
4605 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4607 was_rej_mail = TRUE; /* Reset if accepted */
4608 env_mail_type_t * mail_args; /* Sanity check & validate args */
4611 if (fl.helo_required)
4613 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4614 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4615 "HELO/EHLO given", host_and_ident(FALSE));
4618 else if (mailmax < 0)
4619 mailmax = expand_mailmax(smtp_accept_max_per_connection);
4623 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4624 US"sender already given");
4628 if (!*smtp_cmd_data)
4630 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4631 US"MAIL must have an address operand");
4635 /* Check to see if the limit for messages per connection would be
4636 exceeded by accepting further messages. */
4638 if (mailmax > 0 && smtp_mailcmd_count > mailmax)
4640 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4641 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4642 "messages in one connection", host_and_ident(TRUE));
4646 /* Reset for start of message - even if this is going to fail, we
4647 obviously need to throw away any previous data. */
4649 cancel_cutthrough_connection(TRUE, US"MAIL received");
4650 reset_point = smtp_reset(reset_point);
4652 sender_data = recipient_data = NULL;
4654 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4656 if (fl.esmtp) for(;;)
4658 uschar *name, *value, *end;
4659 unsigned long int size;
4660 BOOL arg_error = FALSE;
4662 if (!extract_option(&name, &value)) break;
4664 for (mail_args = env_mail_type_list;
4665 mail_args->value != ENV_MAIL_OPT_NULL;
4668 if (strcmpic(name, mail_args->name) == 0)
4670 if (mail_args->need_value && strcmpic(value, US"") == 0)
4673 switch(mail_args->value)
4675 /* Handle SIZE= by reading the value. We don't do the check till later,
4676 in order to be able to log the sender address on failure. */
4677 case ENV_MAIL_OPT_SIZE:
4678 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4680 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4682 message_size = (int)size;
4688 /* If this session was initiated with EHLO and accept_8bitmime is set,
4689 Exim will have indicated that it supports the BODY=8BITMIME option. In
4690 fact, it does not support this according to the RFCs, in that it does not
4691 take any special action for forwarding messages containing 8-bit
4692 characters. That is why accept_8bitmime is not the default setting, but
4693 some sites want the action that is provided. We recognize both "8BITMIME"
4694 and "7BIT" as body types, but take no action. */
4695 case ENV_MAIL_OPT_BODY:
4696 if (accept_8bitmime) {
4697 if (strcmpic(value, US"8BITMIME") == 0)
4699 else if (strcmpic(value, US"7BIT") == 0)
4704 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4705 US"invalid data for BODY");
4708 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4714 /* Handle the two DSN options, but only if configured to do so (which
4715 will have caused "DSN" to be given in the EHLO response). The code itself
4716 is included only if configured in at build time. */
4718 case ENV_MAIL_OPT_RET:
4719 if (fl.dsn_advertised)
4721 /* Check if RET has already been set */
4724 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4725 US"RET can be specified once only");
4728 dsn_ret = strcmpic(value, US"HDRS") == 0
4730 : strcmpic(value, US"FULL") == 0
4733 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4734 /* Check for invalid invalid value, and exit with error */
4737 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4738 US"Value for RET is invalid");
4743 case ENV_MAIL_OPT_ENVID:
4744 if (fl.dsn_advertised)
4746 /* Check if the dsn envid has been already set */
4749 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4750 US"ENVID can be specified once only");
4753 dsn_envid = string_copy(value);
4754 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4758 /* Handle the AUTH extension. If the value given is not "<>" and either
4759 the ACL says "yes" or there is no ACL but the sending host is
4760 authenticated, we set it up as the authenticated sender. However, if the
4761 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4762 the condition is met. The value of AUTH is an xtext, which means that +,
4763 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4765 case ENV_MAIL_OPT_AUTH:
4766 if (Ustrcmp(value, "<>") != 0)
4771 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4773 /* Put back terminator overrides for error message */
4776 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4777 US"invalid data for AUTH");
4780 if (!acl_smtp_mailauth)
4782 ignore_msg = US"client not authenticated";
4783 rc = sender_host_authenticated ? OK : FAIL;
4787 ignore_msg = US"rejected by ACL";
4788 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4789 &user_msg, &log_msg);
4795 if (authenticated_by == NULL ||
4796 authenticated_by->mail_auth_condition == NULL ||
4797 expand_check_condition(authenticated_by->mail_auth_condition,
4798 authenticated_by->name, US"authenticator"))
4799 break; /* Accept the AUTH */
4801 ignore_msg = US"server_mail_auth_condition failed";
4802 if (authenticated_id != NULL)
4803 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4804 ignore_msg, authenticated_id);
4809 authenticated_sender = NULL;
4810 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4811 value, host_and_ident(TRUE), ignore_msg);
4814 /* Should only get DEFER or ERROR here. Put back terminator
4815 overrides for error message */
4820 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4827 #ifndef DISABLE_PRDR
4828 case ENV_MAIL_OPT_PRDR:
4830 prdr_requested = TRUE;
4835 case ENV_MAIL_OPT_UTF8:
4836 if (!fl.smtputf8_advertised)
4838 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4839 US"SMTPUTF8 used when not advertised");
4843 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4844 message_smtputf8 = allow_utf8_domains = TRUE;
4845 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4847 int old_pool = store_pool;
4848 store_pool = POOL_PERM;
4849 received_protocol = string_sprintf("utf8%s", received_protocol);
4850 store_pool = old_pool;
4855 /* No valid option. Stick back the terminator characters and break
4856 the loop. Do the name-terminator second as extract_option sets
4857 value==name when it found no equal-sign.
4858 An error for a malformed address will occur. */
4859 case ENV_MAIL_OPT_NULL:
4867 /* Break out of for loop if switch() had bad argument or
4868 when start of the email address is reached */
4869 if (arg_error) break;
4872 /* If we have passed the threshold for rate limiting, apply the current
4873 delay, and update it for next time, provided this is a limited host. */
4875 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4876 verify_check_host(&smtp_ratelimit_hosts) == OK)
4878 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4879 smtp_delay_mail/1000.0);
4880 millisleep((int)smtp_delay_mail);
4881 smtp_delay_mail *= smtp_rlm_factor;
4882 if (smtp_delay_mail > (double)smtp_rlm_limit)
4883 smtp_delay_mail = (double)smtp_rlm_limit;
4886 /* Now extract the address, first applying any SMTP-time rewriting. The
4887 TRUE flag allows "<>" as a sender address. */
4889 raw_sender = rewrite_existflags & rewrite_smtp
4890 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4891 global_rewrite_rules)
4895 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4900 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4904 sender_address = raw_sender;
4906 /* If there is a configured size limit for mail, check that this message
4907 doesn't exceed it. The check is postponed to this point so that the sender
4910 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4912 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4913 log_write(L_size_reject,
4914 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4915 "message too big: size%s=%d max=%d",
4917 host_and_ident(TRUE),
4918 (message_size == INT_MAX)? ">" : "",
4920 thismessage_size_limit);
4921 sender_address = NULL;
4925 /* Check there is enough space on the disk unless configured not to.
4926 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4927 plus the current message - i.e. we accept the message only if it won't
4928 reduce the space below the threshold. Add 5000 to the size to allow for
4929 overheads such as the Received: line and storing of recipients, etc.
4930 By putting the check here, even when SIZE is not given, it allow VRFY
4931 and EXPN etc. to be used when space is short. */
4933 if (!receive_check_fs(
4934 smtp_check_spool_space && message_size >= 0
4935 ? message_size + 5000 : 0))
4937 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4938 sender_address = NULL;
4942 /* If sender_address is unqualified, reject it, unless this is a locally
4943 generated message, or the sending host or net is permitted to send
4944 unqualified addresses - typically local machines behaving as MUAs -
4945 in which case just qualify the address. The flag is set above at the start
4946 of the SMTP connection. */
4948 if (!sender_domain && *sender_address)
4949 if (f.allow_unqualified_sender)
4951 sender_domain = Ustrlen(sender_address) + 1;
4952 sender_address = rewrite_address_qualify(sender_address, FALSE);
4953 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4958 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4960 log_write(L_smtp_syntax_error,
4961 LOG_MAIN|LOG_REJECT,
4962 "unqualified sender rejected: <%s> %s%s",
4964 host_and_ident(TRUE),
4966 sender_address = NULL;
4970 /* Apply an ACL check if one is defined, before responding. Afterwards,
4971 when pipelining is not advertised, do another sync check in case the ACL
4972 delayed and the client started sending in the meantime. */
4976 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4977 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4983 if (rc == OK || rc == DISCARD)
4985 BOOL more = pipeline_response();
4988 smtp_printf("%s%s%s", more, US"250 OK",
4989 #ifndef DISABLE_PRDR
4990 prdr_requested ? US", PRDR Requested" : US"",
4997 #ifndef DISABLE_PRDR
4999 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5001 smtp_user_msg(US"250", user_msg);
5003 smtp_delay_rcpt = smtp_rlr_base;
5004 f.recipients_discarded = (rc == DISCARD);
5005 was_rej_mail = FALSE;
5009 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5010 sender_address = NULL;
5015 /* The RCPT command requires an address as an operand. There may be any
5016 number of RCPT commands, specifying multiple recipients. We build them all
5017 into a data structure. The start/end values given by parse_extract_address
5018 are not used, as we keep only the extracted address. */
5023 was_rcpt = fl.rcpt_in_progress = TRUE;
5025 /* There must be a sender address; if the sender was rejected and
5026 pipelining was advertised, we assume the client was pipelining, and do not
5027 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5028 get the same treatment. */
5030 if (sender_address == NULL)
5032 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5034 smtp_printf("503 sender not yet given\r\n", FALSE);
5035 was_rej_mail = TRUE;
5039 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5040 US"sender not yet given");
5041 was_rcpt = FALSE; /* Not a valid RCPT */
5047 /* Check for an operand */
5049 if (smtp_cmd_data[0] == 0)
5051 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5052 US"RCPT must have an address operand");
5057 /* Set the DSN flags orcpt and dsn_flags from the session*/
5061 if (fl.esmtp) for(;;)
5063 uschar *name, *value;
5065 if (!extract_option(&name, &value))
5068 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5070 /* Check whether orcpt has been already set */
5073 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5074 US"ORCPT can be specified once only");
5077 orcpt = string_copy(value);
5078 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5081 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5083 /* Check if the notify flags have been already set */
5086 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5087 US"NOTIFY can be specified once only");
5090 if (strcmpic(value, US"NEVER") == 0)
5091 dsn_flags |= rf_notify_never;
5098 while (*pp != 0 && *pp != ',') pp++;
5099 if (*pp == ',') *pp++ = 0;
5100 if (strcmpic(p, US"SUCCESS") == 0)
5102 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5103 dsn_flags |= rf_notify_success;
5105 else if (strcmpic(p, US"FAILURE") == 0)
5107 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5108 dsn_flags |= rf_notify_failure;
5110 else if (strcmpic(p, US"DELAY") == 0)
5112 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5113 dsn_flags |= rf_notify_delay;
5117 /* Catch any strange values */
5118 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5119 US"Invalid value for NOTIFY parameter");
5124 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5128 /* Unknown option. Stick back the terminator characters and break
5129 the loop. An error for a malformed address will occur. */
5133 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5140 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5141 as a recipient address */
5143 recipient = rewrite_existflags & rewrite_smtp
5144 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5145 global_rewrite_rules)
5148 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5149 &recipient_domain, FALSE)))
5151 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5156 /* If the recipient address is unqualified, reject it, unless this is a
5157 locally generated message. However, unqualified addresses are permitted
5158 from a configured list of hosts and nets - typically when behaving as
5159 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5160 really. The flag is set at the start of the SMTP connection.
5162 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5163 assumed this meant "reserved local part", but the revision of RFC 821 and
5164 friends now makes it absolutely clear that it means *mailbox*. Consequently
5165 we must always qualify this address, regardless. */
5167 if (!recipient_domain)
5168 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5175 /* Check maximum allowed */
5177 if (rcpt_count > recipients_max && recipients_max > 0)
5179 if (recipients_max_reject)
5182 smtp_printf("552 too many recipients\r\n", FALSE);
5184 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5185 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5190 smtp_printf("452 too many recipients\r\n", FALSE);
5192 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5193 "temporarily rejected: sender=<%s> %s", sender_address,
5194 host_and_ident(TRUE));
5201 /* If we have passed the threshold for rate limiting, apply the current
5202 delay, and update it for next time, provided this is a limited host. */
5204 if (rcpt_count > smtp_rlr_threshold &&
5205 verify_check_host(&smtp_ratelimit_hosts) == OK)
5207 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5208 smtp_delay_rcpt/1000.0);
5209 millisleep((int)smtp_delay_rcpt);
5210 smtp_delay_rcpt *= smtp_rlr_factor;
5211 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5212 smtp_delay_rcpt = (double)smtp_rlr_limit;
5215 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5216 for them. Otherwise, check the access control list for this recipient. As
5217 there may be a delay in this, re-check for a synchronization error
5218 afterwards, unless pipelining was advertised. */
5220 if (f.recipients_discarded)
5223 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5225 && !f.smtp_in_pipelining_advertised && !check_sync())
5228 /* The ACL was happy */
5232 BOOL more = pipeline_response();
5235 smtp_user_msg(US"250", user_msg);
5237 smtp_printf("250 Accepted\r\n", more);
5238 receive_add_recipient(recipient, -1);
5240 /* Set the dsn flags in the recipients_list */
5241 recipients_list[recipients_count-1].orcpt = orcpt;
5242 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5244 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5245 recipients_list[recipients_count-1].orcpt,
5246 recipients_list[recipients_count-1].dsn_flags); */
5249 /* The recipient was discarded */
5251 else if (rc == DISCARD)
5254 smtp_user_msg(US"250", user_msg);
5256 smtp_printf("250 Accepted\r\n", FALSE);
5259 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5260 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5261 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5262 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5263 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5266 /* Either the ACL failed the address, or it was deferred. */
5270 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5271 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5276 /* The DATA command is legal only if it follows successful MAIL FROM
5277 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5278 not counted as a protocol error if it follows RCPT (which must have been
5279 rejected if there are no recipients.) This function is complete when a
5280 valid DATA command is encountered.
5282 Note concerning the code used: RFC 2821 says this:
5284 - If there was no MAIL, or no RCPT, command, or all such commands
5285 were rejected, the server MAY return a "command out of sequence"
5286 (503) or "no valid recipients" (554) reply in response to the
5289 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5290 because it is the same whether pipelining is in use or not.
5292 If all the RCPT commands that precede DATA provoked the same error message
5293 (often indicating some kind of system error), it is helpful to include it
5294 with the DATA rejection (an idea suggested by Tony Finch). */
5301 if (chunking_state != CHUNKING_OFFERED)
5303 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5304 US"BDAT command used when CHUNKING not advertised");
5308 /* grab size, endmarker */
5310 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5312 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5313 US"missing size for BDAT command");
5316 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5317 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5318 chunking_data_left = chunking_datasize;
5319 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5320 (int)chunking_state, chunking_data_left);
5322 f.bdat_readers_wanted = TRUE;
5331 f.bdat_readers_wanted = FALSE
5333 DATA_BDAT: /* Common code for DATA and BDAT */
5334 #ifndef DISABLE_PIPE_CONNECT
5335 fl.pipe_connect_acceptable = FALSE;
5337 if (!discarded && recipients_count <= 0)
5339 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5341 uschar *code = US"503";
5342 int len = Ustrlen(rcpt_smtp_response);
5343 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5345 /* Responses from smtp_printf() will have \r\n on the end */
5346 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5347 rcpt_smtp_response[len-2] = 0;
5348 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5350 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5351 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5352 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5354 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5355 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5356 ? US"valid RCPT command must precede DATA"
5357 : US"valid RCPT command must precede BDAT");
5359 if (chunking_state > CHUNKING_OFFERED)
5361 bdat_push_receive_functions();
5367 if (toomany && recipients_max_reject)
5369 sender_address = NULL; /* This will allow a new MAIL without RSET */
5370 sender_address_unrewritten = NULL;
5371 smtp_printf("554 Too many recipients\r\n", FALSE);
5375 if (chunking_state > CHUNKING_OFFERED)
5376 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5379 /* If there is an ACL, re-check the synchronization afterwards, since the
5380 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5381 to get the DATA command sent. */
5383 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5387 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5388 f.enable_dollar_recipients = TRUE;
5389 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5391 f.enable_dollar_recipients = FALSE;
5392 if (rc == OK && !check_sync())
5396 { /* Either the ACL failed the address, or it was deferred. */
5397 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5402 if (f.bdat_readers_wanted)
5403 bdat_push_receive_functions();
5406 smtp_user_msg(US"354", user_msg);
5409 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5413 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5414 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5415 US &on, sizeof(on));
5418 message_ended = END_NOTENDED; /* Indicate in middle of data */
5429 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5430 &start, &end, &recipient_domain, FALSE)))
5432 smtp_printf("501 %s\r\n", FALSE, errmess);
5436 if (!recipient_domain)
5437 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5441 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5442 &user_msg, &log_msg)) != OK)
5443 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5447 address_item * addr = deliver_make_addr(address, FALSE);
5449 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5450 -1, -1, NULL, NULL, NULL))
5453 s = string_sprintf("250 <%s> is deliverable", address);
5457 s = (addr->user_message != NULL)?
5458 string_sprintf("451 <%s> %s", address, addr->user_message) :
5459 string_sprintf("451 Cannot resolve <%s> at this time", address);
5463 s = (addr->user_message != NULL)?
5464 string_sprintf("550 <%s> %s", address, addr->user_message) :
5465 string_sprintf("550 <%s> is not deliverable", address);
5466 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5467 smtp_cmd_argument, host_and_ident(TRUE));
5471 smtp_printf("%s\r\n", FALSE, s);
5479 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5481 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5484 BOOL save_log_testing_mode = f.log_testing_mode;
5485 f.address_test_mode = f.log_testing_mode = TRUE;
5486 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5487 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5489 f.address_test_mode = FALSE;
5490 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5499 if (!fl.tls_advertised)
5501 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5502 US"STARTTLS command used when not advertised");
5506 /* Apply an ACL check if one is defined */
5508 if ( acl_smtp_starttls
5509 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5510 &user_msg, &log_msg)) != OK
5513 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5517 /* RFC 2487 is not clear on when this command may be sent, though it
5518 does state that all information previously obtained from the client
5519 must be discarded if a TLS session is started. It seems reasonable to
5520 do an implied RSET when STARTTLS is received. */
5522 incomplete_transaction_log(US"STARTTLS");
5523 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5524 reset_point = smtp_reset(reset_point);
5526 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5528 /* There's an attack where more data is read in past the STARTTLS command
5529 before TLS is negotiated, then assumed to be part of the secure session
5530 when used afterwards; we use segregated input buffers, so are not
5531 vulnerable, but we want to note when it happens and, for sheer paranoia,
5532 ensure that the buffer is "wiped".
5533 Pipelining sync checks will normally have protected us too, unless disabled
5534 by configuration. */
5536 if (receive_smtp_buffered())
5539 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5540 if (tls_in.active.sock < 0)
5541 smtp_inend = smtp_inptr = smtp_inbuffer;
5542 /* and if TLS is already active, tls_server_start() should fail */
5545 /* There is nothing we value in the input buffer and if TLS is successfully
5546 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5547 fresh content into it. The buffer contains arbitrary content from an
5548 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5549 It seems safest to just wipe away the content rather than leave it as a
5550 target to jump to. */
5552 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5554 /* Attempt to start up a TLS session, and if successful, discard all
5555 knowledge that was obtained previously. At least, that's what the RFC says,
5556 and that's what happens by default. However, in order to work round YAEB,
5557 there is an option to remember the esmtp state. Sigh.
5559 We must allow for an extra EHLO command and an extra AUTH command after
5560 STARTTLS that don't add to the nonmail command count. */
5563 if ((rc = tls_server_start(&s)) == OK)
5565 if (!tls_remember_esmtp)
5566 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5567 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5568 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5569 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5570 if (sender_helo_name)
5572 sender_helo_name = NULL;
5573 host_build_sender_fullhost(); /* Rebuild */
5574 set_process_info("handling incoming TLS connection from %s",
5575 host_and_ident(FALSE));
5578 (sender_host_address ? protocols : protocols_local)
5580 ? pextend + (sender_host_authenticated ? pauthed : 0)
5582 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5585 sender_host_auth_pubname = sender_host_authenticated = NULL;
5586 authenticated_id = NULL;
5587 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5588 DEBUG(D_tls) debug_printf("TLS active\n");
5589 break; /* Successful STARTTLS */
5592 (void) smtp_log_tls_fail(s);
5594 /* Some local configuration problem was discovered before actually trying
5595 to do a TLS handshake; give a temporary error. */
5599 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5603 /* Hard failure. Reject everything except QUIT or closed connection. One
5604 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5605 set, but we must still reject all incoming commands. Another is a handshake
5606 failure - and there may some encrypted data still in the pipe to us, which we
5607 see as garbage commands. */
5609 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5610 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5613 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5614 smtp_get_connection_info());
5615 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5619 /* It is perhaps arguable as to which exit ACL should be called here,
5620 but as it is probably a situation that almost never arises, it
5621 probably doesn't matter. We choose to call the real QUIT ACL, which in
5622 some sense is perhaps "right". */
5625 f.smtp_in_quit = TRUE;
5628 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5629 &log_msg)) == ERROR))
5630 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5633 smtp_respond(US"221", 3, TRUE, user_msg);
5635 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5636 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5637 smtp_get_connection_info());
5642 smtp_printf("554 Security failure\r\n", FALSE);
5645 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5650 /* The ACL for QUIT is provided for gathering statistical information or
5651 similar; it does not affect the response code, but it can supply a custom
5655 smtp_quit_handler(&user_msg, &log_msg);
5661 smtp_rset_handler();
5662 cancel_cutthrough_connection(TRUE, US"RSET received");
5663 reset_point = smtp_reset(reset_point);
5670 smtp_printf("250 OK\r\n", FALSE);
5674 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5675 used, a check will be done for permitted hosts. Show STARTTLS only if not
5676 already in a TLS session and if it would be advertised in the EHLO
5681 smtp_printf("214-Commands supported:\r\n", TRUE);
5685 Ustrcat(buffer, US" AUTH");
5687 if (tls_in.active.sock < 0 &&
5688 verify_check_host(&tls_advertise_hosts) != FAIL)
5689 Ustrcat(buffer, US" STARTTLS");
5691 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5692 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5693 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5694 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5695 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5696 smtp_printf("214%s\r\n", FALSE, buffer);
5702 incomplete_transaction_log(US"connection lost");
5703 smtp_notquit_exit(US"connection-lost", US"421",
5704 US"%s lost input connection", smtp_active_hostname);
5706 /* Don't log by default unless in the middle of a message, as some mailers
5707 just drop the call rather than sending QUIT, and it clutters up the logs.
5710 if (sender_address || recipients_count > 0)
5711 log_write(L_lost_incoming_connection, LOG_MAIN,
5712 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5713 f.sender_host_unknown ? "EOF" : "disconnection",
5714 f.tcp_in_fastopen_logged
5717 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5719 host_and_ident(FALSE), smtp_read_error,
5720 string_timesince(&smtp_connection_start)
5724 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5725 smtp_get_connection_info(),
5726 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5728 string_timesince(&smtp_connection_start)
5739 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5740 US"ETRN is not permitted inside a transaction");
5744 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5745 host_and_ident(FALSE));
5747 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5748 &user_msg, &log_msg)) != OK)
5750 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5754 /* Compute the serialization key for this command. */
5756 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5758 /* If a command has been specified for running as a result of ETRN, we
5759 permit any argument to ETRN. If not, only the # standard form is permitted,
5760 since that is strictly the only kind of ETRN that can be implemented
5761 according to the RFC. */
5763 if (smtp_etrn_command)
5767 etrn_command = smtp_etrn_command;
5768 deliver_domain = smtp_cmd_data;
5769 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5770 US"ETRN processing", &error);
5771 deliver_domain = NULL;
5774 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5776 smtp_printf("458 Internal failure\r\n", FALSE);
5781 /* Else set up to call Exim with the -R option. */
5785 if (*smtp_cmd_data++ != '#')
5787 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5788 US"argument must begin with #");
5791 etrn_command = US"exim -R";
5792 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5793 *queue_name ? 4 : 2,
5794 US"-R", smtp_cmd_data,
5795 US"-MCG", queue_name);
5798 /* If we are host-testing, don't actually do anything. */
5804 debug_printf("ETRN command is: %s\n", etrn_command);
5805 debug_printf("ETRN command execution skipped\n");
5807 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5808 else smtp_user_msg(US"250", user_msg);
5813 /* If ETRN queue runs are to be serialized, check the database to
5814 ensure one isn't already running. */
5816 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5818 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5822 /* Fork a child process and run the command. We don't want to have to
5823 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5824 forking. It should be set that way anyway for external incoming SMTP,
5825 but we save and restore to be tidy. If serialization is required, we
5826 actually run the command in yet another process, so we can wait for it
5827 to complete and then remove the serialization lock. */
5829 oldsignal = signal(SIGCHLD, SIG_IGN);
5831 if ((pid = exim_fork(US"etrn-command")) == 0)
5833 smtp_input = FALSE; /* This process is not associated with the */
5834 (void)fclose(smtp_in); /* SMTP call any more. */
5835 (void)fclose(smtp_out);
5837 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5839 /* If not serializing, do the exec right away. Otherwise, fork down
5840 into another process. */
5842 if ( !smtp_etrn_serialize
5843 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5845 DEBUG(D_exec) debug_print_argv(argv);
5846 exim_nullstd(); /* Ensure std{in,out,err} exist */
5847 execv(CS argv[0], (char *const *)argv);
5848 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5849 etrn_command, strerror(errno));
5850 _exit(EXIT_FAILURE); /* paranoia */
5853 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5854 is, we are in the first subprocess, after forking again. All we can do
5855 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5856 complete, before removing the serialization. */
5859 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5860 "failed: %s", strerror(errno));
5864 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5866 (void)wait(&status);
5867 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5871 enq_end(etrn_serialize_key);
5872 exim_underbar_exit(EXIT_SUCCESS);
5875 /* Back in the top level SMTP process. Check that we started a subprocess
5876 and restore the signal state. */
5880 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5882 smtp_printf("458 Unable to fork process\r\n", FALSE);
5883 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5887 smtp_printf("250 OK\r\n", FALSE);
5889 smtp_user_msg(US"250", user_msg);
5891 signal(SIGCHLD, oldsignal);
5896 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5897 US"unexpected argument data");
5901 /* This currently happens only for NULLs, but could be extended. */
5904 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5905 US"NUL character(s) present (shown as '?')");
5906 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5913 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5914 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5915 c = smtp_inend - smtp_inptr;
5916 if (c > 150) c = 150; /* limit logged amount */
5918 incomplete_transaction_log(US"sync failure");
5919 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5920 "(next input sent too soon: pipelining was%s advertised): "
5921 "rejected \"%s\" %s next input=\"%s\"",
5922 f.smtp_in_pipelining_advertised ? "" : " not",
5923 smtp_cmd_buffer, host_and_ident(TRUE),
5924 string_printing(smtp_inptr));
5925 smtp_notquit_exit(US"synchronization-error", US"554",
5926 US"SMTP synchronization error");
5927 done = 1; /* Pretend eof - drops connection */
5931 case TOO_MANY_NONMAIL_CMD:
5932 s = smtp_cmd_buffer;
5933 while (*s != 0 && !isspace(*s)) s++;
5934 incomplete_transaction_log(US"too many non-mail commands");
5935 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5936 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5937 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5938 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5939 done = 1; /* Pretend eof - drops connection */
5942 #ifdef SUPPORT_PROXY
5943 case PROXY_FAIL_IGNORE_CMD:
5944 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5949 if (unknown_command_count++ >= smtp_max_unknown_commands)
5951 log_write(L_smtp_syntax_error, LOG_MAIN,
5952 "SMTP syntax error in \"%s\" %s %s",
5953 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5954 US"unrecognized command");
5955 incomplete_transaction_log(US"unrecognized command");
5956 smtp_notquit_exit(US"bad-commands", US"500",
5957 US"Too many unrecognized commands");
5959 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5960 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5961 string_printing(smtp_cmd_buffer));
5964 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5965 US"unrecognized command");
5969 /* This label is used by goto's inside loops that want to break out to
5970 the end of the command-processing loop. */
5973 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5974 last_was_rcpt = was_rcpt; /* protocol error handling */
5978 return done - 2; /* Convert yield values */
5984 authres_smtpauth(gstring * g)
5986 if (!sender_host_authenticated)
5989 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5991 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5992 g = authenticated_id
5993 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5994 : string_cat(g, US") reason=x509.auth");
5996 g = authenticated_id
5997 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5998 : string_cat(g, US", no id saved)");
6000 if (authenticated_sender)
6001 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6009 /* End of smtp_in.c */