1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
135 BOOL auth_advertised :1;
137 BOOL tls_advertised :1;
138 # ifdef EXPERIMENTAL_REQUIRETLS
139 BOOL requiretls_advertised :1;
142 BOOL dsn_advertised :1;
144 BOOL helo_required :1;
147 BOOL helo_accept_junk :1;
148 #ifdef EXPERIMENTAL_PIPE_CONNECT
149 BOOL pipe_connect_acceptable :1;
151 BOOL rcpt_smtp_response_same :1;
152 BOOL rcpt_in_progress :1;
153 BOOL smtp_exit_function_called :1;
155 BOOL smtputf8_advertised :1;
158 .helo_required = FALSE,
159 .helo_verify = FALSE,
160 .smtp_exit_function_called = FALSE,
163 static auth_instance *authenticated_by;
164 static int count_nonmail;
165 static int nonmail_command_count;
166 static int synprot_error_count;
167 static int unknown_command_count;
168 static int sync_cmd_limit;
169 static int smtp_write_error = 0;
171 static uschar *rcpt_smtp_response;
172 static uschar *smtp_data_buffer;
173 static uschar *smtp_cmd_data;
175 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
176 final fields of all except AUTH are forced TRUE at the start of a new message
177 setup, to allow one of each between messages that is not counted as a nonmail
178 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
179 allow a new EHLO after starting up TLS.
181 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
182 counted. However, the flag is changed when AUTH is received, so that multiple
183 failing AUTHs will eventually hit the limit. After a successful AUTH, another
184 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
185 forced TRUE, to allow for the re-authentication that can happen at that point.
187 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
188 count of non-mail commands and possibly provoke an error.
190 tls_auth is a pseudo-command, never expected in input. It is activated
191 on TLS startup and looks for a tls authenticator. */
193 static smtp_cmd_list cmd_list[] = {
194 /* name len cmd has_arg is_mail_cmd */
196 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
197 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
198 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
199 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
201 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
202 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
205 /* If you change anything above here, also fix the definitions below. */
207 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
208 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
209 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
210 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
211 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
212 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
213 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
214 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
215 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
216 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
219 static smtp_cmd_list *cmd_list_end =
220 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
222 #define CMD_LIST_RSET 0
223 #define CMD_LIST_HELO 1
224 #define CMD_LIST_EHLO 2
225 #define CMD_LIST_AUTH 3
226 #define CMD_LIST_STARTTLS 4
227 #define CMD_LIST_TLS_AUTH 5
229 /* This list of names is used for performing the smtp_no_mail logging action.
230 It must be kept in step with the SCH_xxx enumerations. */
232 static uschar *smtp_names[] =
234 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
235 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
236 US"STARTTLS", US"VRFY" };
238 static uschar *protocols_local[] = {
239 US"local-smtp", /* HELO */
240 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
241 US"local-esmtp", /* EHLO */
242 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
243 US"local-esmtpa", /* EHLO->AUTH */
244 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
246 static uschar *protocols[] = {
248 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
249 US"esmtp", /* EHLO */
250 US"esmtps", /* EHLO->STARTTLS->EHLO */
251 US"esmtpa", /* EHLO->AUTH */
252 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
257 #define pcrpted 1 /* added to pextend or pnormal */
258 #define pauthed 2 /* added to pextend */
260 /* Sanity check and validate optional args to MAIL FROM: envelope */
263 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
267 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 #ifdef EXPERIMENTAL_REQUIRETLS
276 uschar * name; /* option requested during MAIL cmd */
277 int value; /* enum type */
278 BOOL need_value; /* TRUE requires value (name=value pair format)
279 FALSE is a singleton */
281 static env_mail_type_t env_mail_type_list[] = {
282 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
283 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
284 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
286 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
288 { US"RET", ENV_MAIL_OPT_RET, TRUE },
289 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
291 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
293 #ifdef EXPERIMENTAL_REQUIRETLS
294 /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */
295 { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE },
297 /* keep this the last entry */
298 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
301 /* When reading SMTP from a remote host, we have to use our own versions of the
302 C input-reading functions, in order to be able to flush the SMTP output only
303 when about to read more data from the socket. This is the only way to get
304 optimal performance when the client is using pipelining. Flushing for every
305 command causes a separate packet and reply packet each time; saving all the
306 responses up (when pipelining) combines them into one packet and one response.
308 For simplicity, these functions are used for *all* SMTP input, not only when
309 receiving over a socket. However, after setting up a secure socket (SSL), input
310 is read via the OpenSSL library, and another set of functions is used instead
313 These functions are set in the receive_getc etc. variables and called with the
314 same interface as the C functions. However, since there can only ever be
315 one incoming SMTP call, we just use a single buffer and flags. There is no need
316 to implement a complicated private FILE-like structure.*/
318 static uschar *smtp_inbuffer;
319 static uschar *smtp_inptr;
320 static uschar *smtp_inend;
321 static int smtp_had_eof;
322 static int smtp_had_error;
325 /* forward declarations */
326 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
327 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
328 static void smtp_quit_handler(uschar **, uschar **);
329 static void smtp_rset_handler(void);
331 /*************************************************
332 * Recheck synchronization *
333 *************************************************/
335 /* Synchronization checks can never be perfect because a packet may be on its
336 way but not arrived when the check is done. Normally, the checks happen when
337 commands are read: Exim ensures that there is no more input in the input buffer.
338 In normal cases, the response to the command will be fast, and there is no
341 However, for some commands an ACL is run, and that can include delays. In those
342 cases, it is useful to do another check on the input just before sending the
343 response. This also applies at the start of a connection. This function does
344 that check by means of the select() function, as long as the facility is not
345 disabled or inappropriate. A failure of select() is ignored.
347 When there is unwanted input, we read it so that it appears in the log of the
351 Returns: TRUE if all is well; FALSE if there is input pending
355 wouldblock_reading(void)
359 struct timeval tzero;
362 if (tls_in.active.sock >= 0)
363 return !tls_could_read();
366 if (smtp_inptr < smtp_inend)
369 fd = fileno(smtp_in);
374 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
376 if (rc <= 0) return TRUE; /* Not ready to read */
377 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
378 if (rc < 0) return TRUE; /* End of file or error */
387 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
390 return wouldblock_reading();
394 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
395 a reponse with the one following. */
398 pipeline_response(void)
400 if ( !smtp_enforce_sync || !sender_host_address
401 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
404 if (wouldblock_reading()) return FALSE;
405 f.smtp_in_pipelining_used = TRUE;
410 #ifdef EXPERIMENTAL_PIPE_CONNECT
412 pipeline_connect_sends(void)
414 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
417 if (wouldblock_reading()) return FALSE;
418 f.smtp_in_early_pipe_used = TRUE;
423 /*************************************************
424 * Log incomplete transactions *
425 *************************************************/
427 /* This function is called after a transaction has been aborted by RSET, QUIT,
428 connection drops or other errors. It logs the envelope information received
429 so far in order to preserve address verification attempts.
431 Argument: string to indicate what aborted the transaction
436 incomplete_transaction_log(uschar *what)
438 if (sender_address == NULL || /* No transaction in progress */
439 !LOGGING(smtp_incomplete_transaction))
442 /* Build list of recipients for logging */
444 if (recipients_count > 0)
447 raw_recipients = store_get(recipients_count * sizeof(uschar *));
448 for (i = 0; i < recipients_count; i++)
449 raw_recipients[i] = recipients_list[i].address;
450 raw_recipients_count = recipients_count;
453 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
454 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
461 smtp_command_timeout_exit(void)
463 log_write(L_lost_incoming_connection,
464 LOG_MAIN, "SMTP command timeout on%s connection from %s",
465 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
466 if (smtp_batched_input)
467 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
468 smtp_notquit_exit(US"command-timeout", US"421",
469 US"%s: SMTP command timeout - closing connection",
470 smtp_active_hostname);
471 exim_exit(EXIT_FAILURE, US"receiving");
475 smtp_command_sigterm_exit(void)
477 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
478 if (smtp_batched_input)
479 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
480 smtp_notquit_exit(US"signal-exit", US"421",
481 US"%s: Service not available - closing connection", smtp_active_hostname);
482 exim_exit(EXIT_FAILURE, US"receiving");
486 smtp_data_timeout_exit(void)
488 log_write(L_lost_incoming_connection,
489 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
490 sender_fullhost ? sender_fullhost : US"local process", sender_address);
491 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
492 /* Does not return */
496 smtp_data_sigint_exit(void)
498 log_write(0, LOG_MAIN, "%s closed after %s",
499 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
500 receive_bomb_out(US"signal-exit",
501 US"Service not available - SIGTERM or SIGINT received");
502 /* Does not return */
507 /* Refill the buffer, and notify DKIM verification code.
508 Return false for error or EOF.
512 smtp_refill(unsigned lim)
515 if (!smtp_out) return FALSE;
517 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
519 /* Limit amount read, so non-message data is not fed to DKIM.
520 Take care to not touch the safety NUL at the end of the buffer. */
522 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
524 if (smtp_receive_timeout > 0) ALARM_CLR(0);
527 /* Must put the error text in fixed store, because this might be during
528 header reading, where it releases unused store above the header. */
531 if (had_command_timeout) /* set by signal handler */
532 smtp_command_timeout_exit(); /* does not return */
533 if (had_command_sigterm)
534 smtp_command_sigterm_exit();
535 if (had_data_timeout)
536 smtp_data_timeout_exit();
538 smtp_data_sigint_exit();
540 smtp_had_error = save_errno;
541 smtp_read_error = string_copy_malloc(
542 string_sprintf(" (error: %s)", strerror(save_errno)));
549 dkim_exim_verify_feed(smtp_inbuffer, rc);
551 smtp_inend = smtp_inbuffer + rc;
552 smtp_inptr = smtp_inbuffer;
556 /*************************************************
557 * SMTP version of getc() *
558 *************************************************/
560 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
561 it flushes the output, and refills the buffer, with a timeout. The signal
562 handler is set appropriately by the calling function. This function is not used
563 after a connection has negotiated itself into an TLS/SSL state.
565 Arguments: lim Maximum amount to read/buffer
566 Returns: the next character or EOF
570 smtp_getc(unsigned lim)
572 if (smtp_inptr >= smtp_inend)
573 if (!smtp_refill(lim))
575 return *smtp_inptr++;
579 smtp_getbuf(unsigned * len)
584 if (smtp_inptr >= smtp_inend)
585 if (!smtp_refill(*len))
586 { *len = 0; return NULL; }
588 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
599 int n = smtp_inend - smtp_inptr;
601 dkim_exim_verify_feed(smtp_inptr, n);
606 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
607 previous BDAT chunk and getting new ones when we run out. Uses the
608 underlying smtp_getc or tls_getc both for that and for getting the
609 (buffered) data byte. EOD signals (an expected) no further data.
610 ERR signals a protocol error, and EOF a closed input stream.
612 Called from read_bdat_smtp() in receive.c for the message body, but also
613 by the headers read loop in receive_msg(); manipulates chunking_state
614 to handle the BDAT command/response.
615 Placed here due to the correlation with the above smtp_getc(), which it wraps,
616 and also by the need to do smtp command/response handling.
618 Arguments: lim (ignored)
619 Returns: the next character or ERR, EOD or EOF
623 bdat_getc(unsigned lim)
625 uschar * user_msg = NULL;
634 if (chunking_data_left > 0)
635 return lwr_receive_getc(chunking_data_left--);
637 receive_getc = lwr_receive_getc;
638 receive_getbuf = lwr_receive_getbuf;
639 receive_ungetc = lwr_receive_ungetc;
641 dkim_save = dkim_collect_input;
642 dkim_collect_input = 0;
645 /* Unless PIPELINING was offered, there should be no next command
646 until after we ack that chunk */
648 if (!f.smtp_in_pipelining_advertised && !check_sync())
650 unsigned n = smtp_inend - smtp_inptr;
653 incomplete_transaction_log(US"sync failure");
654 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
655 "(next input sent too soon: pipelining was not advertised): "
656 "rejected \"%s\" %s next input=\"%s\"%s",
657 smtp_cmd_buffer, host_and_ident(TRUE),
658 string_printing(string_copyn(smtp_inptr, n)),
659 smtp_inend - smtp_inptr > n ? "..." : "");
660 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
661 US"SMTP synchronization error");
662 goto repeat_until_rset;
665 /* If not the last, ack the received chunk. The last response is delayed
666 until after the data ACL decides on it */
668 if (chunking_state == CHUNKING_LAST)
671 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
676 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
677 chunking_state = CHUNKING_OFFERED;
678 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
680 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
681 QUIT, RSET or NOOP but handling them seems obvious */
684 switch(smtp_read_command(TRUE, 1))
687 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
688 US"only BDAT permissible after non-LAST BDAT");
691 switch(smtp_read_command(TRUE, 1))
693 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
694 case EOF_CMD: return EOF;
695 case RSET_CMD: smtp_rset_handler(); return ERR;
696 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
697 US"only RSET accepted now") > 0)
699 goto repeat_until_rset;
703 smtp_quit_handler(&user_msg, &log_msg);
714 smtp_printf("250 OK\r\n", FALSE);
721 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
723 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
724 US"missing size for BDAT command");
727 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
728 ? CHUNKING_LAST : CHUNKING_ACTIVE;
729 chunking_data_left = chunking_datasize;
730 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
731 (int)chunking_state, chunking_data_left);
733 if (chunking_datasize == 0)
734 if (chunking_state == CHUNKING_LAST)
738 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
739 US"zero size for BDAT command");
740 goto repeat_until_rset;
743 receive_getc = bdat_getc;
744 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
745 receive_ungetc = bdat_ungetc;
747 dkim_collect_input = dkim_save;
749 break; /* to top of main loop */
756 bdat_getbuf(unsigned * len)
760 if (chunking_data_left <= 0)
761 { *len = 0; return NULL; }
763 if (*len > chunking_data_left) *len = chunking_data_left;
764 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
765 chunking_data_left -= *len;
770 bdat_flush_data(void)
772 while (chunking_data_left)
774 unsigned n = chunking_data_left;
775 if (!bdat_getbuf(&n)) break;
778 receive_getc = lwr_receive_getc;
779 receive_getbuf = lwr_receive_getbuf;
780 receive_ungetc = lwr_receive_ungetc;
782 if (chunking_state != CHUNKING_LAST)
784 chunking_state = CHUNKING_OFFERED;
785 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
792 /*************************************************
793 * SMTP version of ungetc() *
794 *************************************************/
796 /* Puts a character back in the input buffer. Only ever
802 Returns: the character
816 chunking_data_left++;
817 return lwr_receive_ungetc(ch);
822 /*************************************************
823 * SMTP version of feof() *
824 *************************************************/
826 /* Tests for a previous EOF
829 Returns: non-zero if the eof flag is set
841 /*************************************************
842 * SMTP version of ferror() *
843 *************************************************/
845 /* Tests for a previous read error, and returns with errno
846 restored to what it was when the error was detected.
849 Returns: non-zero if the error flag is set
855 errno = smtp_had_error;
856 return smtp_had_error;
861 /*************************************************
862 * Test for characters in the SMTP buffer *
863 *************************************************/
865 /* Used at the end of a message
874 return smtp_inptr < smtp_inend;
879 /*************************************************
880 * Write formatted string to SMTP channel *
881 *************************************************/
883 /* This is a separate function so that we don't have to repeat everything for
884 TLS support or debugging. It is global so that the daemon and the
885 authentication functions can use it. It does not return any error indication,
886 because major problems such as dropped connections won't show up till an output
887 flush for non-TLS connections. The smtp_fflush() function is available for
888 checking that: for convenience, TLS output errors are remembered here so that
889 they are also picked up later by smtp_fflush().
893 more further data expected
894 ... optional arguments
900 smtp_printf(const char *format, BOOL more, ...)
905 smtp_vprintf(format, more, ap);
909 /* This is split off so that verify.c:respond_printf() can, in effect, call
910 smtp_printf(), bearing in mind that in C a vararg function can't directly
911 call another vararg function, only a function which accepts a va_list. */
914 smtp_vprintf(const char *format, BOOL more, va_list ap)
918 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
922 void *reset_point = store_get(0);
923 uschar *msg_copy, *cr, *end;
924 msg_copy = string_copy(big_buffer);
925 end = msg_copy + Ustrlen(msg_copy);
926 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
927 memmove(cr, cr + 1, (end--) - cr);
928 debug_printf("SMTP>> %s", msg_copy);
929 store_reset(reset_point);
934 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
935 smtp_closedown(US"Unexpected error");
936 exim_exit(EXIT_FAILURE, NULL);
939 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
940 have had the same. Note: this code is also present in smtp_respond(). It would
941 be tidier to have it only in one place, but when it was added, it was easier to
942 do it that way, so as not to have to mess with the code for the RCPT command,
943 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
945 if (fl.rcpt_in_progress)
947 if (rcpt_smtp_response == NULL)
948 rcpt_smtp_response = string_copy(big_buffer);
949 else if (fl.rcpt_smtp_response_same &&
950 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
951 fl.rcpt_smtp_response_same = FALSE;
952 fl.rcpt_in_progress = FALSE;
955 /* Now write the string */
958 if (tls_in.active.sock >= 0)
960 if (tls_write(NULL, big_buffer, Ustrlen(big_buffer), more) < 0)
961 smtp_write_error = -1;
966 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
971 /*************************************************
972 * Flush SMTP out and check for error *
973 *************************************************/
975 /* This function isn't currently used within Exim (it detects errors when it
976 tries to read the next SMTP input), but is available for use in local_scan().
977 For non-TLS connections, it flushes the output and checks for errors. For
978 TLS-connections, it checks for a previously-detected TLS write error.
981 Returns: 0 for no error; -1 after an error
987 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
988 return smtp_write_error;
993 /*************************************************
994 * SMTP command read timeout *
995 *************************************************/
997 /* Signal handler for timing out incoming SMTP commands. This attempts to
1000 Argument: signal number (SIGALRM)
1005 command_timeout_handler(int sig)
1007 had_command_timeout = sig;
1012 /*************************************************
1013 * SIGTERM received *
1014 *************************************************/
1016 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1018 Argument: signal number (SIGTERM)
1023 command_sigterm_handler(int sig)
1025 had_command_sigterm = sig;
1031 #ifdef SUPPORT_PROXY
1032 /*************************************************
1033 * Restore socket timeout to previous value *
1034 *************************************************/
1035 /* If the previous value was successfully retrieved, restore
1036 it before returning control to the non-proxy routines
1038 Arguments: fd - File descriptor for input
1039 get_ok - Successfully retrieved previous values
1040 tvtmp - Time struct with previous values
1041 vslen - Length of time struct
1045 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1048 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1051 /*************************************************
1052 * Check if host is required proxy host *
1053 *************************************************/
1054 /* The function determines if inbound host will be a regular smtp host
1055 or if it is configured that it must use Proxy Protocol. A local
1063 check_proxy_protocol_host()
1067 if ( sender_host_address
1068 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1069 sender_host_address, NULL)) == OK)
1072 debug_printf("Detected proxy protocol configured host\n");
1073 proxy_session = TRUE;
1075 return proxy_session;
1079 /*************************************************
1080 * Read data until newline or end of buffer *
1081 *************************************************/
1082 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1083 read an entire buffer and assume there will be nothing past a proxy protocol
1084 header. Our approach normally is to use stdio, but again that relies upon
1085 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1086 reading _nothing_ before client TLS handshake. So we don't want to use the
1087 usual buffering reads which may read enough to block TLS starting.
1089 So unfortunately we're down to "read one byte at a time, with a syscall each,
1090 and expect a little overhead", for all proxy-opened connections which are v1,
1091 just to handle the TLS-on-connect case. Since SSL functions wrap the
1092 underlying fd, we can't assume that we can feed them any already-read content.
1094 We need to know where to read to, the max capacity, and we'll read until we
1095 get a CR and one more character. Let the caller scream if it's CR+!LF.
1097 Return the amount read.
1101 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1103 uschar *to = base + already;
1109 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1110 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1112 cr = memchr(base, '\r', already);
1115 if ((cr - base) < already - 1)
1117 /* \r and presumed \n already within what we have; probably not
1118 actually proxy protocol, but abort cleanly. */
1121 /* \r is last character read, just need one more. */
1125 while (capacity > 0)
1127 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1139 /* reached end without having room for a final newline, abort */
1144 /*************************************************
1145 * Setup host for proxy protocol *
1146 *************************************************/
1147 /* The function configures the connection based on a header from the
1148 inbound host to use Proxy Protocol. The specification is very exact
1149 so exit with an error if do not find the exact required pieces. This
1150 includes an incorrect number of spaces separating args.
1153 Returns: Boolean success
1157 setup_proxy_protocol_host()
1169 struct { /* TCP/UDP over IPv4, len = 12 */
1175 struct { /* TCP/UDP over IPv6, len = 36 */
1176 uint8_t src_addr[16];
1177 uint8_t dst_addr[16];
1181 struct { /* AF_UNIX sockets, len = 216 */
1182 uschar src_addr[108];
1183 uschar dst_addr[108];
1189 /* Temp variables used in PPv2 address:port parsing */
1191 char tmpip[INET_ADDRSTRLEN];
1192 struct sockaddr_in tmpaddr;
1193 char tmpip6[INET6_ADDRSTRLEN];
1194 struct sockaddr_in6 tmpaddr6;
1196 /* We can't read "all data until end" because while SMTP is
1197 server-speaks-first, the TLS handshake is client-speaks-first, so for
1198 TLS-on-connect ports the proxy protocol header will usually be immediately
1199 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1200 reinject data for reading by those. So instead we first read "enough to be
1201 safely read within the header, and figure out how much more to read".
1202 For v1 we will later read to the end-of-line, for v2 we will read based upon
1205 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1206 data is needed total. For v1, where the line looks like:
1207 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1209 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1210 We seem to support that. So, if we read 14 octets then we can tell if we're
1211 v2 or v1. If we're v1, we can continue reading as normal.
1213 If we're v2, we can't slurp up the entire header. We need the length in the
1214 15th & 16th octets, then to read everything after that.
1216 So to safely handle v1 and v2, with client-sent-first supported correctly,
1217 we have to do a minimum of 3 read calls, not 1. Eww.
1220 #define PROXY_INITIAL_READ 14
1221 #define PROXY_V2_HEADER_SIZE 16
1222 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1223 # error Code bug in sizes of data to read for proxy usage
1228 int fd = fileno(smtp_in);
1229 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1230 uschar * iptype; /* To display debug info */
1232 struct timeval tvtmp;
1233 socklen_t vslen = sizeof(struct timeval);
1236 /* Save current socket timeout values */
1237 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1239 /* Proxy Protocol host must send header within a short time
1240 (default 3 seconds) or it's considered invalid */
1241 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1242 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1243 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1248 /* The inbound host was declared to be a Proxy Protocol host, so
1249 don't do a PEEK into the data, actually slurp up enough to be
1250 "safe". Can't take it all because TLS-on-connect clients follow
1251 immediately with TLS handshake. */
1252 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1254 while (ret == -1 && errno == EINTR);
1259 /* For v2, handle reading the length, and then the rest. */
1260 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1265 /* First get the length fields. */
1268 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1269 } while (retmore == -1 && errno == EINTR);
1274 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1276 /* May 2014: haproxy combined the version and command into one byte to
1277 allow two full bytes for the length field in order to proxy SSL
1278 connections. SSL Proxy is not supported in this version of Exim, but
1279 must still separate values here. */
1283 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1287 /* The v2 header will always be 16 bytes per the spec. */
1288 size = 16 + ntohs(hdr.v2.len);
1289 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1290 size, (int)sizeof(hdr));
1292 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1293 amount that we need. Double-check that the size is not unreasonable, then
1295 if (size > sizeof(hdr))
1297 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1305 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1306 } while (retmore == -1 && errno == EINTR);
1310 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1311 } while (ret < size);
1313 } /* end scope for getting rest of data for v2 */
1315 /* At this point: if PROXYv2, we've read the exact size required for all data;
1316 if PROXYv1 then we've read "less than required for any valid line" and should
1319 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1321 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1325 case 0x01: /* PROXY command */
1328 case 0x11: /* TCPv4 address type */
1330 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1331 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1332 if (!string_is_ip_address(US tmpip, NULL))
1334 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1337 proxy_local_address = sender_host_address;
1338 sender_host_address = string_copy(US tmpip);
1339 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1340 proxy_local_port = sender_host_port;
1341 sender_host_port = tmpport;
1342 /* Save dest ip/port */
1343 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1344 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1345 if (!string_is_ip_address(US tmpip, NULL))
1347 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1350 proxy_external_address = string_copy(US tmpip);
1351 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1352 proxy_external_port = tmpport;
1354 case 0x21: /* TCPv6 address type */
1356 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1357 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1358 if (!string_is_ip_address(US tmpip6, NULL))
1360 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1363 proxy_local_address = sender_host_address;
1364 sender_host_address = string_copy(US tmpip6);
1365 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1366 proxy_local_port = sender_host_port;
1367 sender_host_port = tmpport;
1368 /* Save dest ip/port */
1369 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1370 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1371 if (!string_is_ip_address(US tmpip6, NULL))
1373 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1376 proxy_external_address = string_copy(US tmpip6);
1377 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1378 proxy_external_port = tmpport;
1382 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1386 /* Unsupported protocol, keep local connection address */
1388 case 0x00: /* LOCAL command */
1389 /* Keep local connection address for LOCAL */
1394 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1398 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1402 uschar *sp; /* Utility variables follow */
1407 /* get the rest of the line */
1408 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1413 p = string_copy(hdr.v1.line);
1414 end = memchr(p, '\r', ret - 1);
1416 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1418 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1421 *end = '\0'; /* Terminate the string */
1422 size = end + 2 - p; /* Skip header + CRLF */
1423 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1424 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1425 /* Step through the string looking for the required fields. Ensure
1426 strict adherence to required formatting, exit for any error. */
1428 if (!isspace(*(p++)))
1430 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1433 if (!Ustrncmp(p, CCS"TCP4", 4))
1435 else if (!Ustrncmp(p,CCS"TCP6", 4))
1437 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1439 iptype = US"Unknown";
1444 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1448 p += Ustrlen(iptype);
1449 if (!isspace(*(p++)))
1451 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1454 /* Find the end of the arg */
1455 if ((sp = Ustrchr(p, ' ')) == NULL)
1458 debug_printf("Did not find proxied src %s\n", iptype);
1462 if(!string_is_ip_address(p, NULL))
1465 debug_printf("Proxied src arg is not an %s address\n", iptype);
1468 proxy_local_address = sender_host_address;
1469 sender_host_address = p;
1471 if ((sp = Ustrchr(p, ' ')) == NULL)
1474 debug_printf("Did not find proxy dest %s\n", iptype);
1478 if(!string_is_ip_address(p, NULL))
1481 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1484 proxy_external_address = p;
1486 if ((sp = Ustrchr(p, ' ')) == NULL)
1488 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1492 tmp_port = strtol(CCS p, &endc, 10);
1493 if (*endc || tmp_port == 0)
1496 debug_printf("Proxied src port '%s' not an integer\n", p);
1499 proxy_local_port = sender_host_port;
1500 sender_host_port = tmp_port;
1502 if ((sp = Ustrchr(p, '\0')) == NULL)
1504 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1507 tmp_port = strtol(CCS p, &endc, 10);
1508 if (*endc || tmp_port == 0)
1511 debug_printf("Proxy dest port '%s' not an integer\n", p);
1514 proxy_external_port = tmp_port;
1515 /* Already checked for /r /n above. Good V1 header received. */
1519 /* Wrong protocol */
1520 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1521 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1527 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1528 yield = proxy_session;
1530 /* Don't flush any potential buffer contents. Any input on proxyfail
1531 should cause a synchronization failure */
1534 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1539 sender_host_name = NULL;
1540 (void) host_name_lookup();
1541 host_build_sender_fullhost();
1545 f.proxy_session_failed = TRUE;
1547 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)
1583 BOOL hadnull = FALSE;
1585 had_command_timeout = 0;
1586 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1588 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1590 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1592 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1600 smtp_cmd_buffer[ptr++] = c;
1603 receive_linecount++; /* For BSMTP errors */
1604 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1606 /* If hit end of file, return pseudo EOF command. Whether we have a
1607 part-line already read doesn't matter, since this is an error state. */
1609 if (c == EOF) return EOF_CMD;
1611 /* Remove any CR and white space at the end of the line, and terminate the
1614 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1615 smtp_cmd_buffer[ptr] = 0;
1617 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1619 /* NULLs are not allowed in SMTP commands */
1621 if (hadnull) return BADCHAR_CMD;
1623 /* Scan command list and return identity, having set the data pointer
1624 to the start of the actual data characters. Check for SMTP synchronization
1627 for (p = cmd_list; p < cmd_list_end; p++)
1629 #ifdef SUPPORT_PROXY
1630 /* Only allow QUIT command if Proxy Protocol parsing failed */
1631 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1635 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1636 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1637 || smtp_cmd_buffer[p->len] == 0
1638 || smtp_cmd_buffer[p->len] == ' '
1641 if (smtp_inptr < smtp_inend && /* Outstanding input */
1642 p->cmd < sync_cmd_limit && /* Command should sync */
1643 check_sync && /* Local flag set */
1644 smtp_enforce_sync && /* Global flag set */
1645 sender_host_address != NULL && /* Not local input */
1646 !f.sender_host_notsocket) /* Really is a socket */
1649 /* The variables $smtp_command and $smtp_command_argument point into the
1650 unmodified input buffer. A copy of the latter is taken for actual
1651 processing, so that it can be chopped up into separate parts if necessary,
1652 for example, when processing a MAIL command options such as SIZE that can
1653 follow the sender address. */
1655 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1656 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1657 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1658 smtp_cmd_data = smtp_data_buffer;
1660 /* Count non-mail commands from those hosts that are controlled in this
1661 way. The default is all hosts. We don't waste effort checking the list
1662 until we get a non-mail command, but then cache the result to save checking
1663 again. If there's a DEFER while checking the host, assume it's in the list.
1665 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1666 start of each incoming message by fiddling with the value in the table. */
1668 if (!p->is_mail_cmd)
1670 if (count_nonmail == TRUE_UNSET) count_nonmail =
1671 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1672 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1673 return TOO_MANY_NONMAIL_CMD;
1676 /* If there is data for a command that does not expect it, generate the
1679 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1683 #ifdef SUPPORT_PROXY
1684 /* Only allow QUIT command if Proxy Protocol parsing failed */
1685 if (proxy_session && f.proxy_session_failed)
1686 return PROXY_FAIL_IGNORE_CMD;
1689 /* Enforce synchronization for unknown commands */
1691 if ( smtp_inptr < smtp_inend /* Outstanding input */
1692 && check_sync /* Local flag set */
1693 && smtp_enforce_sync /* Global flag set */
1694 && sender_host_address /* Not local input */
1695 && !f.sender_host_notsocket) /* Really is a socket */
1703 /*************************************************
1704 * Forced closedown of call *
1705 *************************************************/
1707 /* This function is called from log.c when Exim is dying because of a serious
1708 disaster, and also from some other places. If an incoming non-batched SMTP
1709 channel is open, it swallows the rest of the incoming message if in the DATA
1710 phase, sends the reply string, and gives an error to all subsequent commands
1711 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1715 message SMTP reply string to send, excluding the code
1721 smtp_closedown(uschar *message)
1723 if (!smtp_in || smtp_batched_input) return;
1724 receive_swallow_smtp();
1725 smtp_printf("421 %s\r\n", FALSE, message);
1727 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
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 != NULL)
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)
1799 g = string_append(g, 2, US" X=", tls_in.cipher);
1800 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1801 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1802 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1803 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1804 if (LOGGING(tls_sni) && tls_in.sni)
1805 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1810 /*************************************************
1811 * Log lack of MAIL if so configured *
1812 *************************************************/
1814 /* This function is called when an SMTP session ends. If the log selector
1815 smtp_no_mail is set, write a log line giving some details of what has happened
1816 in the SMTP session.
1823 smtp_log_no_mail(void)
1829 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1832 if (sender_host_authenticated)
1834 g = string_append(g, 2, US" A=", sender_host_authenticated);
1835 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1842 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1844 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1845 if (smtp_connection_had[i] != SCH_NONE)
1847 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1851 for (i = 0; i < smtp_ch_index; i++)
1853 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1857 if (!(s = string_from_gstring(g))) s = US"";
1859 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1860 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1861 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1865 /* Return list of recent smtp commands */
1871 gstring * list = NULL;
1874 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1875 if (smtp_connection_had[i] != SCH_NONE)
1876 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1878 for (i = 0; i < smtp_ch_index; i++)
1879 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1881 s = string_from_gstring(list);
1882 return s ? s : US"";
1888 /*************************************************
1889 * Check HELO line and set sender_helo_name *
1890 *************************************************/
1892 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1893 the domain name of the sending host, or an ip literal in square brackets. The
1894 argument is placed in sender_helo_name, which is in malloc store, because it
1895 must persist over multiple incoming messages. If helo_accept_junk is set, this
1896 host is permitted to send any old junk (needed for some broken hosts).
1897 Otherwise, helo_allow_chars can be used for rogue characters in general
1898 (typically people want to let in underscores).
1901 s the data portion of the line (already past any white space)
1903 Returns: TRUE or FALSE
1907 check_helo(uschar *s)
1910 uschar *end = s + Ustrlen(s);
1911 BOOL yield = fl.helo_accept_junk;
1913 /* Discard any previous helo name */
1915 if (sender_helo_name)
1917 store_free(sender_helo_name);
1918 sender_helo_name = NULL;
1921 /* Skip tests if junk is permitted. */
1925 /* Allow the new standard form for IPv6 address literals, namely,
1926 [IPv6:....], and because someone is bound to use it, allow an equivalent
1927 IPv4 form. Allow plain addresses as well. */
1934 if (strncmpic(s, US"[IPv6:", 6) == 0)
1935 yield = (string_is_ip_address(s+6, NULL) == 6);
1936 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1937 yield = (string_is_ip_address(s+6, NULL) == 4);
1939 yield = (string_is_ip_address(s+1, NULL) != 0);
1944 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1945 that have been configured (usually underscore - sigh). */
1948 for (yield = TRUE; *s; s++)
1949 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1950 Ustrchr(helo_allow_chars, *s) == NULL)
1956 /* Save argument if OK */
1958 if (yield) sender_helo_name = string_copy_malloc(start);
1966 /*************************************************
1967 * Extract SMTP command option *
1968 *************************************************/
1970 /* This function picks the next option setting off the end of smtp_cmd_data. It
1971 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1972 things that can appear there.
1975 name point this at the name
1976 value point this at the data string
1978 Returns: TRUE if found an option
1982 extract_option(uschar **name, uschar **value)
1985 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1986 while (isspace(*v)) v--;
1988 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1990 /* Take care to not stop at a space embedded in a quoted local-part */
1992 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1999 while(isalpha(n[-1])) n--;
2000 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2001 if (!isspace(n[-1])) return FALSE;
2007 if (v == smtp_cmd_data) return FALSE;
2019 /*************************************************
2020 * Reset for new message *
2021 *************************************************/
2023 /* This function is called whenever the SMTP session is reset from
2024 within either of the setup functions; also from the daemon loop.
2026 Argument: the stacking pool storage reset point
2031 smtp_reset(void *reset_point)
2033 recipients_list = NULL;
2034 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2035 raw_recipients_count = recipients_count = recipients_list_max = 0;
2036 message_linecount = 0;
2038 acl_added_headers = NULL;
2039 acl_removed_headers = NULL;
2040 f.queue_only_policy = FALSE;
2041 rcpt_smtp_response = NULL;
2042 fl.rcpt_smtp_response_same = TRUE;
2043 fl.rcpt_in_progress = FALSE;
2044 f.deliver_freeze = FALSE; /* Can be set by ACL */
2045 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2046 fake_response = OK; /* Can be set by ACL */
2047 #ifdef WITH_CONTENT_SCAN
2048 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2050 f.submission_mode = FALSE; /* Can be set by ACL */
2051 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2052 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2053 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2054 sending_ip_address = NULL;
2055 return_path = sender_address = NULL;
2056 sender_data = NULL; /* Can be set by ACL */
2057 deliver_localpart_parent = deliver_localpart_orig = NULL;
2058 deliver_domain_parent = deliver_domain_orig = NULL;
2059 callout_address = NULL;
2060 submission_name = NULL; /* Can be set by ACL */
2061 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2062 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2063 sender_verified_list = NULL; /* No senders verified */
2064 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2065 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2067 authenticated_sender = NULL;
2068 #ifdef EXPERIMENTAL_BRIGHTMAIL
2070 bmi_verdicts = NULL;
2072 dnslist_domain = dnslist_matched = NULL;
2074 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2075 spf_result_guessed = FALSE;
2077 #ifndef DISABLE_DKIM
2078 dkim_cur_signer = dkim_signers =
2079 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2080 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2081 f.dkim_disable_verify = FALSE;
2082 dkim_collect_input = 0;
2083 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2084 dkim_key_length = 0;
2085 dkim_verify_signers = US"$dkim_signers";
2087 #ifdef EXPERIMENTAL_DMARC
2088 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2089 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2090 dmarc_used_domain = NULL;
2092 #ifdef EXPERIMENTAL_ARC
2093 arc_state = arc_state_reason = NULL;
2097 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2098 #ifndef DISABLE_PRDR
2099 prdr_requested = FALSE;
2102 message_smtputf8 = FALSE;
2104 body_linecount = body_zerocount = 0;
2106 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2107 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2108 /* Note that ratelimiters_conn persists across resets. */
2110 /* Reset message ACL variables */
2114 /* The message body variables use malloc store. They may be set if this is
2115 not the first message in an SMTP session and the previous message caused them
2116 to be referenced in an ACL. */
2120 store_free(message_body);
2121 message_body = NULL;
2124 if (message_body_end)
2126 store_free(message_body_end);
2127 message_body_end = NULL;
2130 /* Warning log messages are also saved in malloc store. They are saved to avoid
2131 repetition in the same message, but it seems right to repeat them for different
2134 while (acl_warn_logged)
2136 string_item *this = acl_warn_logged;
2137 acl_warn_logged = acl_warn_logged->next;
2140 store_reset(reset_point);
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 void *reset_point = store_get(0);
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 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 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 */
2216 if (sender_address != NULL)
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 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;
2361 /* The function moan_smtp_batch() does not return. */
2362 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2367 /* The function moan_smtp_batch() does not return. */
2368 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2373 /* The function moan_smtp_batch() does not return. */
2374 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2379 return done - 2; /* Convert yield values */
2387 smtp_log_tls_fail(uschar * errstr)
2389 uschar * conn_info = smtp_get_connection_info();
2391 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2392 /* I'd like to get separated H= here, but too hard for now */
2394 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2407 struct tcp_info tinfo;
2408 socklen_t len = sizeof(tinfo);
2410 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2411 #ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11 does not seem to have this yet */
2412 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2414 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n");
2415 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2419 if (tinfo.tcpi_state == TCP_SYN_RECV)
2421 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2422 f.tcp_in_fastopen = TRUE;
2429 /*************************************************
2430 * Start an SMTP session *
2431 *************************************************/
2433 /* This function is called at the start of an SMTP session. Thereafter,
2434 smtp_setup_msg() is called to initiate each separate message. This
2435 function does host-specific testing, and outputs the banner line.
2438 Returns: FALSE if the session can not continue; something has
2439 gone wrong, or the connection to the host is blocked
2443 smtp_start_session(void)
2446 uschar *user_msg, *log_msg;
2451 gettimeofday(&smtp_connection_start, NULL);
2452 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2453 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2456 /* Default values for certain variables */
2458 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2459 smtp_mailcmd_count = 0;
2460 count_nonmail = TRUE_UNSET;
2461 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2462 smtp_delay_mail = smtp_rlm_base;
2463 fl.auth_advertised = FALSE;
2464 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2465 f.pipelining_enable = TRUE;
2466 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2467 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2469 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2470 authentication settings from -oMaa to remain in force. */
2472 if (!host_checking && !f.sender_host_notsocket)
2473 sender_host_auth_pubname = sender_host_authenticated = NULL;
2474 authenticated_by = NULL;
2477 tls_in.cipher = tls_in.peerdn = NULL;
2478 tls_in.ourcert = tls_in.peercert = NULL;
2480 tls_in.ocsp = OCSP_NOT_REQ;
2481 fl.tls_advertised = FALSE;
2482 # ifdef EXPERIMENTAL_REQUIRETLS
2483 fl.requiretls_advertised = FALSE;
2486 fl.dsn_advertised = FALSE;
2488 fl.smtputf8_advertised = FALSE;
2491 /* Reset ACL connection variables */
2495 /* Allow for trailing 0 in the command and data buffers. */
2497 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2498 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2499 "malloc() failed for SMTP command buffer");
2501 smtp_cmd_buffer[0] = 0;
2502 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2504 /* For batched input, the protocol setting can be overridden from the
2505 command line by a trusted caller. */
2507 if (smtp_batched_input)
2509 if (!received_protocol) received_protocol = US"local-bsmtp";
2512 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2513 reset later if any of EHLO/AUTH/STARTTLS are received. */
2517 (sender_host_address ? protocols : protocols_local) [pnormal];
2519 /* Set up the buffer for inputting using direct read() calls, and arrange to
2520 call the local functions instead of the standard C ones. Place a NUL at the
2521 end of the buffer to safety-stop C-string reads from it. */
2523 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2524 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2525 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2527 receive_getc = smtp_getc;
2528 receive_getbuf = smtp_getbuf;
2529 receive_get_cache = smtp_get_cache;
2530 receive_ungetc = smtp_ungetc;
2531 receive_feof = smtp_feof;
2532 receive_ferror = smtp_ferror;
2533 receive_smtp_buffered = smtp_buffered;
2534 smtp_inptr = smtp_inend = smtp_inbuffer;
2535 smtp_had_eof = smtp_had_error = 0;
2537 /* Set up the message size limit; this may be host-specific */
2539 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2540 if (expand_string_message)
2542 if (thismessage_size_limit == -1)
2543 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2544 "%s", expand_string_message);
2546 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2547 "%s", expand_string_message);
2548 smtp_closedown(US"Temporary local problem - please try later");
2552 /* When a message is input locally via the -bs or -bS options, sender_host_
2553 unknown is set unless -oMa was used to force an IP address, in which case it
2554 is checked like a real remote connection. When -bs is used from inetd, this
2555 flag is not set, causing the sending host to be checked. The code that deals
2556 with IP source routing (if configured) is never required for -bs or -bS and
2557 the flag sender_host_notsocket is used to suppress it.
2559 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2560 reserve for certain hosts and/or networks. */
2562 if (!f.sender_host_unknown)
2565 BOOL reserved_host = FALSE;
2567 /* Look up IP options (source routing info) on the socket if this is not an
2568 -oMa "host", and if any are found, log them and drop the connection.
2570 Linux (and others now, see below) is different to everyone else, so there
2571 has to be some conditional compilation here. Versions of Linux before 2.1.15
2572 used a structure whose name was "options". Somebody finally realized that
2573 this name was silly, and it got changed to "ip_options". I use the
2574 newer name here, but there is a fudge in the script that sets up os.h
2575 to define a macro in older Linux systems.
2577 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2578 glibc 2, which has chosen ip_opts for the structure name. This is now
2579 really a glibc thing rather than a Linux thing, so the condition name
2580 has been changed to reflect this. It is relevant also to GNU/Hurd.
2582 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2583 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2584 a special macro defined in the os.h file.
2586 Some DGUX versions on older hardware appear not to support IP options at
2587 all, so there is now a general macro which can be set to cut out this
2590 How to do this properly in IPv6 is not yet known. */
2592 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2594 #ifdef GLIBC_IP_OPTIONS
2595 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2600 #elif defined DARWIN_IP_OPTIONS
2606 if (!host_checking && !f.sender_host_notsocket)
2609 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2610 struct ip_options *ipopt = store_get(optlen);
2612 struct ip_opts ipoptblock;
2613 struct ip_opts *ipopt = &ipoptblock;
2614 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2616 struct ipoption ipoptblock;
2617 struct ipoption *ipopt = &ipoptblock;
2618 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2621 /* Occasional genuine failures of getsockopt() have been seen - for
2622 example, "reset by peer". Therefore, just log and give up on this
2623 call, unless the error is ENOPROTOOPT. This error is given by systems
2624 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2625 of writing. So for that error, carry on - we just can't do an IP options
2628 DEBUG(D_receive) debug_printf("checking for IP options\n");
2630 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2633 if (errno != ENOPROTOOPT)
2635 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2636 host_and_ident(FALSE), strerror(errno));
2637 smtp_printf("451 SMTP service not available\r\n", FALSE);
2642 /* Deal with any IP options that are set. On the systems I have looked at,
2643 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2644 more logging data than will fit in big_buffer. Nevertheless, after somebody
2645 questioned this code, I've added in some paranoid checking. */
2647 else if (optlen > 0)
2649 uschar *p = big_buffer;
2650 uschar *pend = big_buffer + big_buffer_size;
2651 uschar *opt, *adptr;
2653 struct in_addr addr;
2656 uschar *optstart = US (ipopt->__data);
2658 uschar *optstart = US (ipopt->ip_opts);
2660 uschar *optstart = US (ipopt->ipopt_list);
2663 DEBUG(D_receive) debug_printf("IP options exist\n");
2665 Ustrcpy(p, "IP options on incoming call:");
2668 for (opt = optstart; opt != NULL &&
2669 opt < US (ipopt) + optlen;)
2683 if (!string_format(p, pend-p, " %s [@%s",
2684 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2686 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2688 inet_ntoa(ipopt->ip_dst)))
2690 inet_ntoa(ipopt->ipopt_dst)))
2698 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2700 while (optcount-- > 0)
2702 memcpy(&addr, adptr, sizeof(addr));
2703 if (!string_format(p, pend - p - 1, "%s%s",
2704 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2710 adptr += sizeof(struct in_addr);
2719 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2722 for (i = 0; i < opt[1]; i++)
2723 p += sprintf(CS p, "%2.2x ", opt[i]);
2732 log_write(0, LOG_MAIN, "%s", big_buffer);
2734 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2736 log_write(0, LOG_MAIN|LOG_REJECT,
2737 "connection from %s refused (IP options)", host_and_ident(FALSE));
2739 smtp_printf("554 SMTP service not available\r\n", FALSE);
2743 /* Length of options = 0 => there are no options */
2745 else DEBUG(D_receive) debug_printf("no IP options found\n");
2747 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2749 /* Set keep-alive in socket options. The option is on by default. This
2750 setting is an attempt to get rid of some hanging connections that stick in
2751 read() when the remote end (usually a dialup) goes away. */
2753 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2754 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2756 /* If the current host matches host_lookup, set the name by doing a
2757 reverse lookup. On failure, sender_host_name will be NULL and
2758 host_lookup_failed will be TRUE. This may or may not be serious - optional
2761 if (verify_check_host(&host_lookup) == OK)
2763 (void)host_name_lookup();
2764 host_build_sender_fullhost();
2767 /* Delay this until we have the full name, if it is looked up. */
2769 set_process_info("handling incoming connection from %s",
2770 host_and_ident(FALSE));
2772 /* Expand smtp_receive_timeout, if needed */
2774 if (smtp_receive_timeout_s)
2777 if ( !(exp = expand_string(smtp_receive_timeout_s))
2779 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2781 log_write(0, LOG_MAIN|LOG_PANIC,
2782 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2785 /* Test for explicit connection rejection */
2787 if (verify_check_host(&host_reject_connection) == OK)
2789 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2790 "from %s (host_reject_connection)", host_and_ident(FALSE));
2791 smtp_printf("554 SMTP service not available\r\n", FALSE);
2795 /* Test with TCP Wrappers if so configured. There is a problem in that
2796 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2797 such as disks dying. In these cases, it is desirable to reject with a 4xx
2798 error instead of a 5xx error. There isn't a "right" way to detect such
2799 problems. The following kludge is used: errno is zeroed before calling
2800 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2801 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2804 #ifdef USE_TCP_WRAPPERS
2806 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2807 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2808 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2809 expand_string_message);
2811 if (!hosts_ctl(tcp_wrappers_name,
2812 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2813 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2814 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2816 if (errno == 0 || errno == ENOENT)
2818 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2819 log_write(L_connection_reject,
2820 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2821 "(tcp wrappers)", host_and_ident(FALSE));
2822 smtp_printf("554 SMTP service not available\r\n", FALSE);
2826 int save_errno = errno;
2827 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2828 "errno value %d\n", save_errno);
2829 log_write(L_connection_reject,
2830 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2831 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2832 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2838 /* Check for reserved slots. The value of smtp_accept_count has already been
2839 incremented to include this process. */
2841 if (smtp_accept_max > 0 &&
2842 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2844 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2846 log_write(L_connection_reject,
2847 LOG_MAIN, "temporarily refused connection from %s: not in "
2848 "reserve list: connected=%d max=%d reserve=%d%s",
2849 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2850 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2851 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2852 "please try again later\r\n", FALSE, smtp_active_hostname);
2855 reserved_host = TRUE;
2858 /* If a load level above which only messages from reserved hosts are
2859 accepted is set, check the load. For incoming calls via the daemon, the
2860 check is done in the superior process if there are no reserved hosts, to
2861 save a fork. In all cases, the load average will already be available
2862 in a global variable at this point. */
2864 if (smtp_load_reserve >= 0 &&
2865 load_average > smtp_load_reserve &&
2867 verify_check_host(&smtp_reserve_hosts) != OK)
2869 log_write(L_connection_reject,
2870 LOG_MAIN, "temporarily refused connection from %s: not in "
2871 "reserve list and load average = %.2f", host_and_ident(FALSE),
2872 (double)load_average/1000.0);
2873 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2874 smtp_active_hostname);
2878 /* Determine whether unqualified senders or recipients are permitted
2879 for this host. Unfortunately, we have to do this every time, in order to
2880 set the flags so that they can be inspected when considering qualifying
2881 addresses in the headers. For a site that permits no qualification, this
2882 won't take long, however. */
2884 f.allow_unqualified_sender =
2885 verify_check_host(&sender_unqualified_hosts) == OK;
2887 f.allow_unqualified_recipient =
2888 verify_check_host(&recipient_unqualified_hosts) == OK;
2890 /* Determine whether HELO/EHLO is required for this host. The requirement
2891 can be hard or soft. */
2893 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2894 if (!fl.helo_required)
2895 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2897 /* Determine whether this hosts is permitted to send syntactic junk
2898 after a HELO or EHLO command. */
2900 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2903 /* For batch SMTP input we are now done. */
2905 if (smtp_batched_input) return TRUE;
2907 /* If valid Proxy Protocol source is connecting, set up session.
2908 * Failure will not allow any SMTP function other than QUIT. */
2910 #ifdef SUPPORT_PROXY
2911 proxy_session = FALSE;
2912 f.proxy_session_failed = FALSE;
2913 if (check_proxy_protocol_host())
2914 setup_proxy_protocol_host();
2917 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2918 smtps port for use with older style SSL MTAs. */
2921 if (tls_in.on_connect)
2923 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2924 return smtp_log_tls_fail(user_msg);
2925 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2929 /* Run the connect ACL if it exists */
2932 if (acl_smtp_connect)
2935 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2938 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2943 /* Output the initial message for a two-way SMTP connection. It may contain
2944 newlines, which then cause a multi-line response to be given. */
2946 code = US"220"; /* Default status code */
2947 esc = US""; /* Default extended status code */
2948 esclen = 0; /* Length of esc */
2952 if (!(s = expand_string(smtp_banner)))
2953 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2954 "failed: %s", smtp_banner, expand_string_message);
2960 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2964 esclen = codelen - 4;
2968 /* Remove any terminating newlines; might as well remove trailing space too */
2971 while (p > s && isspace(p[-1])) p--;
2974 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2975 is all contained in a single IP packet. The original code wrote out the
2976 greeting using several calls to fprint/fputc, and on busy servers this could
2977 cause it to be split over more than one packet - which caused CC:Mail to fall
2978 over when it got the second part of the greeting after sending its first
2979 command. Sigh. To try to avoid this, build the complete greeting message
2980 first, and output it in one fell swoop. This gives a better chance of it
2981 ending up as a single packet. */
2983 ss = string_get(256);
2986 do /* At least once, in case we have an empty string */
2989 uschar *linebreak = Ustrchr(p, '\n');
2990 ss = string_catn(ss, code, 3);
2994 ss = string_catn(ss, US" ", 1);
2998 len = linebreak - p;
2999 ss = string_catn(ss, US"-", 1);
3001 ss = string_catn(ss, esc, esclen);
3002 ss = string_catn(ss, p, len);
3003 ss = string_catn(ss, US"\r\n", 2);
3009 /* Before we write the banner, check that there is no input pending, unless
3010 this synchronisation check is disabled. */
3012 #ifdef EXPERIMENTAL_PIPE_CONNECT
3013 fl.pipe_connect_acceptable =
3014 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3017 if (fl.pipe_connect_acceptable)
3018 f.smtp_in_early_pipe_used = TRUE;
3024 unsigned n = smtp_inend - smtp_inptr;
3027 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3028 "synchronization error (input sent without waiting for greeting): "
3029 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3030 string_printing(string_copyn(smtp_inptr, n)));
3031 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3035 /* Now output the banner */
3036 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3039 #ifdef EXPERIMENTAL_PIPE_CONNECT
3040 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3044 string_from_gstring(ss));
3046 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3047 handshake arrived. If so we must have managed a TFO. */
3060 /*************************************************
3061 * Handle SMTP syntax and protocol errors *
3062 *************************************************/
3064 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3065 to do so. Then transmit the error response. The return value depends on the
3066 number of syntax and protocol errors in this SMTP session.
3069 type error type, given as a log flag bit
3070 code response code; <= 0 means don't send a response
3071 data data to reflect in the response (can be NULL)
3072 errmess the error message
3074 Returns: -1 limit of syntax/protocol errors NOT exceeded
3075 +1 limit of syntax/protocol errors IS exceeded
3077 These values fit in with the values of the "done" variable in the main
3078 processing loop in smtp_setup_msg(). */
3081 synprot_error(int type, int code, uschar *data, uschar *errmess)
3085 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3086 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3087 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3089 if (++synprot_error_count > smtp_max_synprot_errors)
3092 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3093 "syntax or protocol errors (last command was \"%s\")",
3094 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3099 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3100 data ? data : US"", data ? US": " : US"", errmess);
3102 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3111 /*************************************************
3112 * Send SMTP response, possibly multiline *
3113 *************************************************/
3115 /* There are, it seems, broken clients out there that cannot handle multiline
3116 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3117 output nothing for non-final calls, and only the first line for anything else.
3120 code SMTP code, may involve extended status codes
3121 codelen length of smtp code; if > 4 there's an ESC
3122 final FALSE if the last line isn't the final line
3123 msg message text, possibly containing newlines
3129 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3134 if (!final && f.no_multiline_responses) return;
3139 esclen = codelen - 4;
3142 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3143 have had the same. Note: this code is also present in smtp_printf(). It would
3144 be tidier to have it only in one place, but when it was added, it was easier to
3145 do it that way, so as not to have to mess with the code for the RCPT command,
3146 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3148 if (fl.rcpt_in_progress)
3150 if (rcpt_smtp_response == NULL)
3151 rcpt_smtp_response = string_copy(msg);
3152 else if (fl.rcpt_smtp_response_same &&
3153 Ustrcmp(rcpt_smtp_response, msg) != 0)
3154 fl.rcpt_smtp_response_same = FALSE;
3155 fl.rcpt_in_progress = FALSE;
3158 /* Now output the message, splitting it up into multiple lines if necessary.
3159 We only handle pipelining these responses as far as nonfinal/final groups,
3160 not the whole MAIL/RCPT/DATA response set. */
3164 uschar *nl = Ustrchr(msg, '\n');
3167 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3170 else if (nl[1] == 0 || f.no_multiline_responses)
3172 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3173 (int)(nl - msg), msg);
3178 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3180 while (isspace(*msg)) msg++;
3188 /*************************************************
3189 * Parse user SMTP message *
3190 *************************************************/
3192 /* This function allows for user messages overriding the response code details
3193 by providing a suitable response code string at the start of the message
3194 user_msg. Check the message for starting with a response code and optionally an
3195 extended status code. If found, check that the first digit is valid, and if so,
3196 change the code pointer and length to use the replacement. An invalid code
3197 causes a panic log; in this case, if the log messages is the same as the user
3198 message, we must also adjust the value of the log message to show the code that
3199 is actually going to be used (the original one).
3201 This function is global because it is called from receive.c as well as within
3204 Note that the code length returned includes the terminating whitespace
3205 character, which is always included in the regex match.
3208 code SMTP code, may involve extended status codes
3209 codelen length of smtp code; if > 4 there's an ESC
3211 log_msg optional log message, to be adjusted with the new SMTP code
3212 check_valid if true, verify the response code
3218 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3224 if (!msg || !*msg) return;
3226 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3227 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3229 if (check_valid && (*msg)[0] != (*code)[0])
3231 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3232 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3233 if (log_msg != NULL && *log_msg == *msg)
3234 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3239 *codelen = ovector[1]; /* Includes final space */
3241 *msg += ovector[1]; /* Chop the code off the message */
3248 /*************************************************
3249 * Handle an ACL failure *
3250 *************************************************/
3252 /* This function is called when acl_check() fails. As well as calls from within
3253 this module, it is called from receive.c for an ACL after DATA. It sorts out
3254 logging the incident, and sends the error response. A message containing
3255 newlines is turned into a multiline SMTP response, but for logging, only the
3258 There's a table of default permanent failure response codes to use in
3259 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3260 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3261 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3262 state, because there are broken clients that try VRFY before RCPT. A 5xx
3263 response should be given only when the address is positively known to be
3264 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3265 no explicit code, but if there is one we let it know best.
3266 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3268 From Exim 4.63, it is possible to override the response code details by
3269 providing a suitable response code string at the start of the message provided
3270 in user_msg. The code's first digit is checked for validity.
3273 where where the ACL was called from
3275 user_msg a message that can be included in an SMTP response
3276 log_msg a message for logging
3278 Returns: 0 in most cases
3279 2 if the failure code was FAIL_DROP, in which case the
3280 SMTP connection should be dropped (this value fits with the
3281 "done" variable in smtp_setup_msg() below)
3285 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3287 BOOL drop = rc == FAIL_DROP;
3291 uschar *sender_info = US"";
3293 #ifdef WITH_CONTENT_SCAN
3294 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3296 where == ACL_WHERE_PREDATA ? US"DATA" :
3297 where == ACL_WHERE_DATA ? US"after DATA" :
3298 #ifndef DISABLE_PRDR
3299 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3302 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3303 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3305 if (drop) rc = FAIL;
3307 /* Set the default SMTP code, and allow a user message to change it. */
3309 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3310 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3311 where != ACL_WHERE_VRFY);
3313 /* We used to have sender_address here; however, there was a bug that was not
3314 updating sender_address after a rewrite during a verify. When this bug was
3315 fixed, sender_address at this point became the rewritten address. I'm not sure
3316 this is what should be logged, so I've changed to logging the unrewritten
3317 address to retain backward compatibility. */
3319 #ifndef WITH_CONTENT_SCAN
3320 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3322 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3325 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3326 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3327 sender_host_authenticated ? US" A=" : US"",
3328 sender_host_authenticated ? sender_host_authenticated : US"",
3329 sender_host_authenticated && authenticated_id ? US":" : US"",
3330 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3334 /* If there's been a sender verification failure with a specific message, and
3335 we have not sent a response about it yet, do so now, as a preliminary line for
3336 failures, but not defers. However, always log it for defer, and log it for fail
3337 unless the sender_verify_fail log selector has been turned off. */
3339 if (sender_verified_failed &&
3340 !testflag(sender_verified_failed, af_sverify_told))
3342 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3343 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3345 setflag(sender_verified_failed, af_sverify_told);
3347 if (rc != FAIL || LOGGING(sender_verify_fail))
3348 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3349 host_and_ident(TRUE),
3350 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3351 sender_verified_failed->address,
3352 (sender_verified_failed->message == NULL)? US"" :
3353 string_sprintf(": %s", sender_verified_failed->message));
3355 if (rc == FAIL && sender_verified_failed->user_message)
3356 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3357 testflag(sender_verified_failed, af_verify_pmfail)?
3358 "Postmaster verification failed while checking <%s>\n%s\n"
3359 "Several RFCs state that you are required to have a postmaster\n"
3360 "mailbox for each mail domain. This host does not accept mail\n"
3361 "from domains whose servers reject the postmaster address."
3363 testflag(sender_verified_failed, af_verify_nsfail)?
3364 "Callback setup failed while verifying <%s>\n%s\n"
3365 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3366 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3367 "RFC requirements, and stops you from receiving standard bounce\n"
3368 "messages. This host does not accept mail from domains whose servers\n"
3371 "Verification failed for <%s>\n%s",
3372 sender_verified_failed->address,
3373 sender_verified_failed->user_message));
3375 fl.rcpt_in_progress = save_rcpt_in_progress;
3378 /* Sort out text for logging */
3380 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3381 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3383 /* Send permanent failure response to the command, but the code used isn't
3384 always a 5xx one - see comments at the start of this function. If the original
3385 rc was FAIL_DROP we drop the connection and yield 2. */
3388 smtp_respond(smtp_code, codelen, TRUE,
3389 user_msg ? user_msg : US"Administrative prohibition");
3391 /* Send temporary failure response to the command. Don't give any details,
3392 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3393 verb, and for a header verify when smtp_return_error_details is set.
3395 This conditional logic is all somewhat of a mess because of the odd
3396 interactions between temp_details and return_error_details. One day it should
3397 be re-implemented in a tidier fashion. */
3400 if (f.acl_temp_details && user_msg)
3402 if ( smtp_return_error_details
3403 && sender_verified_failed
3404 && sender_verified_failed->message
3406 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3408 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3411 smtp_respond(smtp_code, codelen, TRUE,
3412 US"Temporary local problem - please try later");
3414 /* Log the incident to the logs that are specified by log_reject_target
3415 (default main, reject). This can be empty to suppress logging of rejections. If
3416 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3417 is closing if required and return 2. */
3419 if (log_reject_target != 0)
3422 gstring * g = s_tlslog(NULL);
3423 uschar * tls = string_from_gstring(g);
3424 if (!tls) tls = US"";
3426 uschar * tls = US"";
3428 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3429 log_reject_target, "%s%s%s %s%srejected %s%s",
3430 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3431 host_and_ident(TRUE),
3434 rc == FAIL ? US"" : US"temporarily ",
3438 if (!drop) return 0;
3440 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3441 smtp_get_connection_info());
3443 /* Run the not-quit ACL, but without any custom messages. This should not be a
3444 problem, because we get here only if some other ACL has issued "drop", and
3445 in that case, *its* custom messages will have been used above. */
3447 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3454 /*************************************************
3455 * Handle SMTP exit when QUIT is not given *
3456 *************************************************/
3458 /* This function provides a logging/statistics hook for when an SMTP connection
3459 is dropped on the floor or the other end goes away. It's a global function
3460 because it's called from receive.c as well as this module. As well as running
3461 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3462 response, either with a custom message from the ACL, or using a default. There
3463 is one case, however, when no message is output - after "drop". In that case,
3464 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3465 passed to this function.
3467 In case things go wrong while processing this function, causing an error that
3468 may re-enter this function, there is a recursion check.
3471 reason What $smtp_notquit_reason will be set to in the ACL;
3472 if NULL, the ACL is not run
3473 code The error code to return as part of the response
3474 defaultrespond The default message if there's no user_msg
3480 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3483 uschar *user_msg = NULL;
3484 uschar *log_msg = NULL;
3486 /* Check for recursive acll */
3488 if (fl.smtp_exit_function_called)
3490 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3494 fl.smtp_exit_function_called = TRUE;
3496 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3498 if (acl_smtp_notquit && reason)
3500 smtp_notquit_reason = reason;
3501 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3502 &log_msg)) == ERROR)
3503 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3507 /* If the connection was dropped, we certainly are no longer talking TLS */
3508 tls_in.active.sock = -1;
3510 /* Write an SMTP response if we are expected to give one. As the default
3511 responses are all internal, they should always fit in the buffer, but code a
3512 warning, just in case. Note that string_vformat() still leaves a complete
3513 string, even if it is incomplete. */
3515 if (code && defaultrespond)
3518 smtp_respond(code, 3, TRUE, user_msg);
3523 va_start(ap, defaultrespond);
3524 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3525 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3526 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3536 /*************************************************
3537 * Verify HELO argument *
3538 *************************************************/
3540 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3541 matched. It is also called from ACL processing if verify = helo is used and
3542 verification was not previously tried (i.e. helo_try_verify_hosts was not
3543 matched). The result of its processing is to set helo_verified and
3544 helo_verify_failed. These variables should both be FALSE for this function to
3547 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3548 for IPv6 ::ffff: literals.
3551 Returns: TRUE if testing was completed;
3552 FALSE on a temporary failure
3556 smtp_verify_helo(void)
3560 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3563 if (sender_helo_name == NULL)
3565 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3568 /* Deal with the case of -bs without an IP address */
3570 else if (sender_host_address == NULL)
3572 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3573 f.helo_verified = TRUE;
3576 /* Deal with the more common case when there is a sending IP address */
3578 else if (sender_helo_name[0] == '[')
3580 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3581 Ustrlen(sender_host_address)) == 0;
3584 if (!f.helo_verified)
3586 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3587 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3588 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3593 { if (f.helo_verified) debug_printf("matched host address\n"); }
3596 /* Do a reverse lookup if one hasn't already given a positive or negative
3597 response. If that fails, or the name doesn't match, try checking with a forward
3602 if (sender_host_name == NULL && !host_lookup_failed)
3603 yield = host_name_lookup() != DEFER;
3605 /* If a host name is known, check it and all its aliases. */
3607 if (sender_host_name)
3608 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3610 sender_helo_dnssec = sender_host_dnssec;
3611 HDEBUG(D_receive) debug_printf("matched host name\n");
3615 uschar **aliases = sender_host_aliases;
3617 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3619 sender_helo_dnssec = sender_host_dnssec;
3623 HDEBUG(D_receive) if (f.helo_verified)
3624 debug_printf("matched alias %s\n", *(--aliases));
3627 /* Final attempt: try a forward lookup of the helo name */
3629 if (!f.helo_verified)
3636 h.name = sender_helo_name;
3643 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3645 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3646 NULL, NULL, NULL, &d, NULL, NULL);
3647 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3648 for (hh = &h; hh; hh = hh->next)
3649 if (Ustrcmp(hh->address, sender_host_address) == 0)
3651 f.helo_verified = TRUE;
3652 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3655 debug_printf("IP address for %s matches calling address\n"
3656 "Forward DNS security status: %sverified\n",
3657 sender_helo_name, sender_helo_dnssec ? "" : "un");
3664 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3671 /*************************************************
3672 * Send user response message *
3673 *************************************************/
3675 /* This function is passed a default response code and a user message. It calls
3676 smtp_message_code() to check and possibly modify the response code, and then
3677 calls smtp_respond() to transmit the response. I put this into a function
3678 just to avoid a lot of repetition.
3681 code the response code
3682 user_msg the user message
3688 smtp_user_msg(uschar *code, uschar *user_msg)
3691 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3692 smtp_respond(code, len, TRUE, user_msg);
3698 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3700 const uschar *set_id = NULL;
3703 /* Run the checking code, passing the remainder of the command line as
3704 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3705 it as the only set numerical variable. The authenticator may set $auth<n>
3706 and also set other numeric variables. The $auth<n> variables are preferred
3707 nowadays; the numerical variables remain for backwards compatibility.
3709 Afterwards, have a go at expanding the set_id string, even if
3710 authentication failed - for bad passwords it can be useful to log the
3711 userid. On success, require set_id to expand and exist, and put it in
3712 authenticated_id. Save this in permanent store, as the working store gets
3713 reset at HELO, RSET, etc. */
3715 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3717 expand_nlength[0] = 0; /* $0 contains nothing */
3719 rc = (au->info->servercode)(au, smtp_cmd_data);
3720 if (au->set_id) set_id = expand_string(au->set_id);
3721 expand_nmax = -1; /* Reset numeric variables */
3722 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3724 /* The value of authenticated_id is stored in the spool file and printed in
3725 log lines. It must not contain binary zeros or newline characters. In
3726 normal use, it never will, but when playing around or testing, this error
3727 can (did) happen. To guard against this, ensure that the id contains only
3728 printing characters. */
3730 if (set_id) set_id = string_printing(set_id);
3732 /* For the non-OK cases, set up additional logging data if set_id
3736 set_id = set_id && *set_id
3737 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3739 /* Switch on the result */
3744 if (!au->set_id || set_id) /* Complete success */
3746 if (set_id) authenticated_id = string_copy_malloc(set_id);
3747 sender_host_authenticated = au->name;
3748 sender_host_auth_pubname = au->public_name;
3749 authentication_failed = FALSE;
3750 authenticated_fail_id = NULL; /* Impossible to already be set? */
3753 (sender_host_address ? protocols : protocols_local)
3754 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3755 *s = *ss = US"235 Authentication succeeded";
3756 authenticated_by = au;
3760 /* Authentication succeeded, but we failed to expand the set_id string.
3761 Treat this as a temporary error. */
3763 auth_defer_msg = expand_string_message;
3767 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3768 *s = string_sprintf("435 Unable to authenticate at present%s",
3769 auth_defer_user_msg);
3770 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3771 set_id, auth_defer_msg);
3775 *s = *ss = US"501 Invalid base64 data";
3779 *s = *ss = US"501 Authentication cancelled";
3783 *s = *ss = US"553 Initial data not expected";
3787 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3788 *s = US"535 Incorrect authentication data";
3789 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3793 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3794 *s = US"435 Internal error";
3795 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3796 "check", set_id, rc);
3808 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3811 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3813 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3815 rd = Ustrlen(recipient) + 1;
3816 *recipient = rewrite_address_qualify(*recipient, TRUE);
3819 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3821 log_write(L_smtp_syntax_error,
3822 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3823 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3831 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3834 incomplete_transaction_log(US"QUIT");
3837 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3839 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3843 smtp_respond(US"221", 3, TRUE, *user_msgp);
3845 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3848 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3851 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3852 smtp_get_connection_info());
3857 smtp_rset_handler(void)
3860 incomplete_transaction_log(US"RSET");
3861 smtp_printf("250 Reset OK\r\n", FALSE);
3862 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3867 /*************************************************
3868 * Initialize for SMTP incoming message *
3869 *************************************************/
3871 /* This function conducts the initial dialogue at the start of an incoming SMTP
3872 message, and builds a list of recipients. However, if the incoming message
3873 is part of a batch (-bS option) a separate function is called since it would
3874 be messy having tests splattered about all over this function. This function
3875 therefore handles the case where interaction is occurring. The input and output
3876 files are set up in smtp_in and smtp_out.
3878 The global recipients_list is set to point to a vector of recipient_item
3879 blocks, whose number is given by recipients_count. This is extended by the
3880 receive_add_recipient() function. The global variable sender_address is set to
3881 the sender's address. The yield is +1 if a message has been successfully
3882 started, 0 if a QUIT command was encountered or the connection was refused from
3883 the particular host, or -1 if the connection was lost.
3887 Returns: > 0 message successfully started (reached DATA)
3888 = 0 QUIT read or end of file reached or call refused
3893 smtp_setup_msg(void)
3896 BOOL toomany = FALSE;
3897 BOOL discarded = FALSE;
3898 BOOL last_was_rej_mail = FALSE;
3899 BOOL last_was_rcpt = FALSE;
3900 void *reset_point = store_get(0);
3902 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3904 /* Reset for start of new message. We allow one RSET not to be counted as a
3905 nonmail command, for those MTAs that insist on sending it between every
3906 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3907 TLS between messages (an Exim client may do this if it has messages queued up
3908 for the host). Note: we do NOT reset AUTH at this point. */
3910 smtp_reset(reset_point);
3911 message_ended = END_NOTSTARTED;
3913 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3915 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3916 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3917 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3919 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3922 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3924 had_command_sigterm = 0;
3925 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3927 /* Batched SMTP is handled in a different function. */
3929 if (smtp_batched_input) return smtp_setup_batch_msg();
3931 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3932 value. The values are 2 larger than the required yield of the function. */
3936 const uschar **argv;
3937 uschar *etrn_command;
3938 uschar *etrn_serialize_key;
3940 uschar *log_msg, *smtp_code;
3941 uschar *user_msg = NULL;
3942 uschar *recipient = NULL;
3943 uschar *hello = NULL;
3945 BOOL was_rej_mail = FALSE;
3946 BOOL was_rcpt = FALSE;
3947 void (*oldsignal)(int);
3949 int start, end, sender_domain, recipient_domain;
3953 uschar *orcpt = NULL;
3958 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3959 if ( tls_in.active.sock >= 0
3961 && tls_in.certificate_verified
3962 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3965 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3967 for (au = auths; au; au = au->next)
3968 if (strcmpic(US"tls", au->driver_name) == 0)
3971 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3972 &user_msg, &log_msg)) != OK
3974 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3977 smtp_cmd_data = NULL;
3979 if (smtp_in_auth(au, &s, &ss) == OK)
3980 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3982 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3990 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3991 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3992 US &off, sizeof(off));
3995 switch(smtp_read_command(
3996 #ifdef EXPERIMENTAL_PIPE_CONNECT
3997 !fl.pipe_connect_acceptable,
4001 GETC_BUFFER_UNLIMITED))
4003 /* The AUTH command is not permitted to occur inside a transaction, and may
4004 occur successfully only once per connection. Actually, that isn't quite
4005 true. When TLS is started, all previous information about a connection must
4006 be discarded, so a new AUTH is permitted at that time.
4008 AUTH may only be used when it has been advertised. However, it seems that
4009 there are clients that send AUTH when it hasn't been advertised, some of
4010 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4011 So there's a get-out that allows this to happen.
4013 AUTH is initially labelled as a "nonmail command" so that one occurrence
4014 doesn't get counted. We change the label here so that multiple failing
4015 AUTHS will eventually hit the nonmail threshold. */
4019 authentication_failed = TRUE;
4020 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4022 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4024 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4025 US"AUTH command used when not advertised");
4028 if (sender_host_authenticated)
4030 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4031 US"already authenticated");
4036 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4037 US"not permitted in mail transaction");
4044 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4045 &user_msg, &log_msg)) != OK
4048 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4052 /* Find the name of the requested authentication mechanism. */
4055 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4057 if (!isalnum(c) && c != '-' && c != '_')
4059 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4060 US"invalid character in authentication mechanism name");
4066 /* If not at the end of the line, we must be at white space. Terminate the
4067 name and move the pointer on to any data that may be present. */
4069 if (*smtp_cmd_data != 0)
4071 *smtp_cmd_data++ = 0;
4072 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4075 /* Search for an authentication mechanism which is configured for use
4076 as a server and which has been advertised (unless, sigh, allow_auth_
4077 unadvertised is set). */
4079 for (au = auths; au; au = au->next)
4080 if (strcmpic(s, au->public_name) == 0 && au->server &&
4081 (au->advertised || f.allow_auth_unadvertised))
4086 c = smtp_in_auth(au, &s, &ss);
4088 smtp_printf("%s\r\n", FALSE, s);
4090 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4091 au->name, host_and_ident(FALSE), ss);
4094 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4095 string_sprintf("%s authentication mechanism not supported", s));
4097 break; /* AUTH_CMD */
4099 /* The HELO/EHLO commands are permitted to appear in the middle of a
4100 session as well as at the beginning. They have the effect of a reset in
4101 addition to their other functions. Their absence at the start cannot be
4102 taken to be an error.
4106 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4107 or 502 failure replies MUST be returned as appropriate. The SMTP
4108 server MUST stay in the same state after transmitting these replies
4109 that it was in before the EHLO was received.
4111 Therefore, we do not do the reset until after checking the command for
4112 acceptability. This change was made for Exim release 4.11. Previously
4113 it did the reset first. */
4126 HELO_EHLO: /* Common code for HELO and EHLO */
4127 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4128 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4130 /* Reject the HELO if its argument was invalid or non-existent. A
4131 successful check causes the argument to be saved in malloc store. */
4133 if (!check_helo(smtp_cmd_data))
4135 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4137 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4138 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4139 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4140 string_printing(smtp_cmd_argument));
4142 if (++synprot_error_count > smtp_max_synprot_errors)
4144 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4145 "syntax or protocol errors (last command was \"%s\")",
4146 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4153 /* If sender_host_unknown is true, we have got here via the -bs interface,
4154 not called from inetd. Otherwise, we are running an IP connection and the
4155 host address will be set. If the helo name is the primary name of this
4156 host and we haven't done a reverse lookup, force one now. If helo_required
4157 is set, ensure that the HELO name matches the actual host. If helo_verify
4158 is set, do the same check, but softly. */
4160 if (!f.sender_host_unknown)
4162 BOOL old_helo_verified = f.helo_verified;
4163 uschar *p = smtp_cmd_data;
4165 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4168 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4169 because otherwise the log can be confusing. */
4171 if ( !sender_host_name
4172 && (deliver_domain = sender_helo_name, /* set $domain */
4173 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4174 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4175 (void)host_name_lookup();
4177 /* Rebuild the fullhost info to include the HELO name (and the real name
4178 if it was looked up.) */
4180 host_build_sender_fullhost(); /* Rebuild */
4181 set_process_info("handling%s incoming connection from %s",
4182 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4184 /* Verify if configured. This doesn't give much security, but it does
4185 make some people happy to be able to do it. If helo_required is set,
4186 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4187 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4188 now obsolescent, since the verification can now be requested selectively
4191 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4192 if (fl.helo_required || fl.helo_verify)
4194 BOOL tempfail = !smtp_verify_helo();
4195 if (!f.helo_verified)
4197 if (fl.helo_required)
4199 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4200 tempfail? 451 : 550, hello);
4201 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4202 tempfail? "temporarily " : "",
4203 hello, sender_helo_name, host_and_ident(FALSE));
4204 f.helo_verified = old_helo_verified;
4205 break; /* End of HELO/EHLO processing */
4207 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4208 "helo_try_verify_hosts\n", hello);
4214 /* set up SPF context */
4215 spf_init(sender_helo_name, sender_host_address);
4218 /* Apply an ACL check if one is defined; afterwards, recheck
4219 synchronization in case the client started sending in a delay. */
4222 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4223 &user_msg, &log_msg)) != OK)
4225 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4226 if (sender_helo_name)
4228 store_free(sender_helo_name);
4229 sender_helo_name = NULL;
4231 host_build_sender_fullhost(); /* Rebuild */
4234 #ifdef EXPERIMENTAL_PIPE_CONNECT
4235 else if (!fl.pipe_connect_acceptable && !check_sync())
4237 else if (!check_sync())
4241 /* Generate an OK reply. The default string includes the ident if present,
4242 and also the IP address if present. Reflecting back the ident is intended
4243 as a deterrent to mail forgers. For maximum efficiency, and also because
4244 some broken systems expect each response to be in a single packet, arrange
4245 that the entire reply is sent in one write(). */
4247 fl.auth_advertised = FALSE;
4248 f.smtp_in_pipelining_advertised = FALSE;
4250 fl.tls_advertised = FALSE;
4251 # ifdef EXPERIMENTAL_REQUIRETLS
4252 fl.requiretls_advertised = FALSE;
4255 fl.dsn_advertised = FALSE;
4257 fl.smtputf8_advertised = FALSE;
4260 smtp_code = US"250 "; /* Default response code plus space*/
4263 s = string_sprintf("%.3s %s Hello %s%s%s",
4265 smtp_active_hostname,
4266 sender_ident ? sender_ident : US"",
4267 sender_ident ? US" at " : US"",
4268 sender_host_name ? sender_host_name : sender_helo_name);
4269 g = string_cat(NULL, s);
4271 if (sender_host_address)
4273 g = string_catn(g, US" [", 2);
4274 g = string_cat (g, sender_host_address);
4275 g = string_catn(g, US"]", 1);
4279 /* A user-supplied EHLO greeting may not contain more than one line. Note
4280 that the code returned by smtp_message_code() includes the terminating
4281 whitespace character. */
4287 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4288 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4289 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4291 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4292 "newlines: message truncated: %s", string_printing(s));
4295 g = string_cat(NULL, s);
4298 g = string_catn(g, US"\r\n", 2);
4300 /* If we received EHLO, we must create a multiline response which includes
4301 the functions supported. */
4307 /* I'm not entirely happy with this, as an MTA is supposed to check
4308 that it has enough room to accept a message of maximum size before
4309 it sends this. However, there seems little point in not sending it.
4310 The actual size check happens later at MAIL FROM time. By postponing it
4311 till then, VRFY and EXPN can be used after EHLO when space is short. */
4313 if (thismessage_size_limit > 0)
4315 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4316 thismessage_size_limit);
4317 g = string_cat(g, big_buffer);
4321 g = string_catn(g, smtp_code, 3);
4322 g = string_catn(g, US"-SIZE\r\n", 7);
4325 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4326 clean; if it has an 8-bit character in its hand, it just sends it. It
4327 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4328 However, some users want this option simply in order to stop MUAs
4329 mangling messages that contain top-bit-set characters. It is therefore
4330 provided as an option. */
4332 if (accept_8bitmime)
4334 g = string_catn(g, smtp_code, 3);
4335 g = string_catn(g, US"-8BITMIME\r\n", 11);
4338 /* Advertise DSN support if configured to do so. */
4339 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4341 g = string_catn(g, smtp_code, 3);
4342 g = string_catn(g, US"-DSN\r\n", 6);
4343 fl.dsn_advertised = TRUE;
4346 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4347 permitted to issue them; a check is made when any host actually tries. */
4351 g = string_catn(g, smtp_code, 3);
4352 g = string_catn(g, US"-ETRN\r\n", 7);
4356 g = string_catn(g, smtp_code, 3);
4357 g = string_catn(g, US"-VRFY\r\n", 7);
4361 g = string_catn(g, smtp_code, 3);
4362 g = string_catn(g, US"-EXPN\r\n", 7);
4365 /* Exim is quite happy with pipelining, so let the other end know that
4366 it is safe to use it, unless advertising is disabled. */
4368 if ( f.pipelining_enable
4369 && verify_check_host(&pipelining_advertise_hosts) == OK)
4371 g = string_catn(g, smtp_code, 3);
4372 g = string_catn(g, US"-PIPELINING\r\n", 13);
4373 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4374 f.smtp_in_pipelining_advertised = TRUE;
4376 #ifdef EXPERIMENTAL_PIPE_CONNECT
4377 if (fl.pipe_connect_acceptable)
4379 f.smtp_in_early_pipe_advertised = TRUE;
4380 g = string_catn(g, smtp_code, 3);
4381 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4387 /* If any server authentication mechanisms are configured, advertise
4388 them if the current host is in auth_advertise_hosts. The problem with
4389 advertising always is that some clients then require users to
4390 authenticate (and aren't configurable otherwise) even though it may not
4391 be necessary (e.g. if the host is in host_accept_relay).
4393 RFC 2222 states that SASL mechanism names contain only upper case
4394 letters, so output the names in upper case, though we actually recognize
4395 them in either case in the AUTH command. */
4399 && !sender_host_authenticated
4401 && verify_check_host(&auth_advertise_hosts) == OK
4406 for (au = auths; au; au = au->next)
4408 au->advertised = FALSE;
4411 DEBUG(D_auth+D_expand) debug_printf_indent(
4412 "Evaluating advertise_condition for %s athenticator\n",
4414 if ( !au->advertise_condition
4415 || expand_check_condition(au->advertise_condition, au->name,
4422 g = string_catn(g, smtp_code, 3);
4423 g = string_catn(g, US"-AUTH", 5);
4425 fl.auth_advertised = TRUE;
4428 g = string_catn(g, US" ", 1);
4429 g = string_cat (g, au->public_name);
4430 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4431 au->advertised = TRUE;
4436 if (!first) g = string_catn(g, US"\r\n", 2);
4439 /* RFC 3030 CHUNKING */
4441 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4443 g = string_catn(g, smtp_code, 3);
4444 g = string_catn(g, US"-CHUNKING\r\n", 11);
4445 f.chunking_offered = TRUE;
4446 chunking_state = CHUNKING_OFFERED;
4449 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4450 if it has been included in the binary, and the host matches
4451 tls_advertise_hosts. We must *not* advertise if we are already in a
4452 secure connection. */
4455 if (tls_in.active.sock < 0 &&
4456 verify_check_host(&tls_advertise_hosts) != FAIL)
4458 g = string_catn(g, smtp_code, 3);
4459 g = string_catn(g, US"-STARTTLS\r\n", 11);
4460 fl.tls_advertised = TRUE;
4463 # ifdef EXPERIMENTAL_REQUIRETLS
4464 /* Advertise REQUIRETLS only once we are in a secure connection */
4465 if ( tls_in.active.sock >= 0
4466 && verify_check_host(&tls_advertise_requiretls) != FAIL)
4468 g = string_catn(g, smtp_code, 3);
4469 g = string_catn(g, US"-REQUIRETLS\r\n", 13);
4470 fl.requiretls_advertised = TRUE;
4475 #ifndef DISABLE_PRDR
4476 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4479 g = string_catn(g, smtp_code, 3);
4480 g = string_catn(g, US"-PRDR\r\n", 7);
4485 if ( accept_8bitmime
4486 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4488 g = string_catn(g, smtp_code, 3);
4489 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4490 fl.smtputf8_advertised = TRUE;
4494 /* Finish off the multiline reply with one that is always available. */
4496 g = string_catn(g, smtp_code, 3);
4497 g = string_catn(g, US" HELP\r\n", 7);
4500 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4504 if (tls_in.active.sock >= 0)
4505 (void)tls_write(NULL, g->s, g->ptr,
4506 # ifdef EXPERIMENTAL_PIPE_CONNECT
4507 fl.pipe_connect_acceptable && pipeline_connect_sends());
4515 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4521 (void) string_from_gstring(g);
4522 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4523 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4524 debug_printf("SMTP>> %s", g->s);
4526 fl.helo_seen = TRUE;
4528 /* Reset the protocol and the state, abandoning any previous message. */
4530 (sender_host_address ? protocols : protocols_local)
4532 ? pextend + (sender_host_authenticated ? pauthed : 0)
4534 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4536 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4537 smtp_reset(reset_point);
4539 break; /* HELO/EHLO */
4542 /* The MAIL command requires an address as an operand. All we do
4543 here is to parse it for syntactic correctness. The form "<>" is
4544 a special case which converts into an empty string. The start/end
4545 pointers in the original are not used further for this address, as
4546 it is the canonical extracted address which is all that is kept. */
4550 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4551 was_rej_mail = TRUE; /* Reset if accepted */
4552 env_mail_type_t * mail_args; /* Sanity check & validate args */
4554 if (fl.helo_required && !fl.helo_seen)
4556 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4557 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4558 "HELO/EHLO given", host_and_ident(FALSE));
4564 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4565 US"sender already given");
4569 if (!*smtp_cmd_data)
4571 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4572 US"MAIL must have an address operand");
4576 /* Check to see if the limit for messages per connection would be
4577 exceeded by accepting further messages. */
4579 if (smtp_accept_max_per_connection > 0 &&
4580 smtp_mailcmd_count > smtp_accept_max_per_connection)
4582 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4583 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4584 "messages in one connection", host_and_ident(TRUE));
4588 /* Reset for start of message - even if this is going to fail, we
4589 obviously need to throw away any previous data. */
4591 cancel_cutthrough_connection(TRUE, US"MAIL received");
4592 smtp_reset(reset_point);
4594 sender_data = recipient_data = NULL;
4596 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4598 if (fl.esmtp) for(;;)
4600 uschar *name, *value, *end;
4601 unsigned long int size;
4602 BOOL arg_error = FALSE;
4604 if (!extract_option(&name, &value)) break;
4606 for (mail_args = env_mail_type_list;
4607 mail_args->value != ENV_MAIL_OPT_NULL;
4610 if (strcmpic(name, mail_args->name) == 0)
4612 if (mail_args->need_value && strcmpic(value, US"") == 0)
4615 switch(mail_args->value)
4617 /* Handle SIZE= by reading the value. We don't do the check till later,
4618 in order to be able to log the sender address on failure. */
4619 case ENV_MAIL_OPT_SIZE:
4620 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4622 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4624 message_size = (int)size;
4630 /* If this session was initiated with EHLO and accept_8bitmime is set,
4631 Exim will have indicated that it supports the BODY=8BITMIME option. In
4632 fact, it does not support this according to the RFCs, in that it does not
4633 take any special action for forwarding messages containing 8-bit
4634 characters. That is why accept_8bitmime is not the default setting, but
4635 some sites want the action that is provided. We recognize both "8BITMIME"
4636 and "7BIT" as body types, but take no action. */
4637 case ENV_MAIL_OPT_BODY:
4638 if (accept_8bitmime) {
4639 if (strcmpic(value, US"8BITMIME") == 0)
4641 else if (strcmpic(value, US"7BIT") == 0)
4646 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4647 US"invalid data for BODY");
4650 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4656 /* Handle the two DSN options, but only if configured to do so (which
4657 will have caused "DSN" to be given in the EHLO response). The code itself
4658 is included only if configured in at build time. */
4660 case ENV_MAIL_OPT_RET:
4661 if (fl.dsn_advertised)
4663 /* Check if RET has already been set */
4666 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4667 US"RET can be specified once only");
4670 dsn_ret = strcmpic(value, US"HDRS") == 0
4672 : strcmpic(value, US"FULL") == 0
4675 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4676 /* Check for invalid invalid value, and exit with error */
4679 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4680 US"Value for RET is invalid");
4685 case ENV_MAIL_OPT_ENVID:
4686 if (fl.dsn_advertised)
4688 /* Check if the dsn envid has been already set */
4691 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4692 US"ENVID can be specified once only");
4695 dsn_envid = string_copy(value);
4696 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4700 /* Handle the AUTH extension. If the value given is not "<>" and either
4701 the ACL says "yes" or there is no ACL but the sending host is
4702 authenticated, we set it up as the authenticated sender. However, if the
4703 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4704 the condition is met. The value of AUTH is an xtext, which means that +,
4705 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4707 case ENV_MAIL_OPT_AUTH:
4708 if (Ustrcmp(value, "<>") != 0)
4713 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4715 /* Put back terminator overrides for error message */
4718 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4719 US"invalid data for AUTH");
4722 if (!acl_smtp_mailauth)
4724 ignore_msg = US"client not authenticated";
4725 rc = sender_host_authenticated ? OK : FAIL;
4729 ignore_msg = US"rejected by ACL";
4730 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4731 &user_msg, &log_msg);
4737 if (authenticated_by == NULL ||
4738 authenticated_by->mail_auth_condition == NULL ||
4739 expand_check_condition(authenticated_by->mail_auth_condition,
4740 authenticated_by->name, US"authenticator"))
4741 break; /* Accept the AUTH */
4743 ignore_msg = US"server_mail_auth_condition failed";
4744 if (authenticated_id != NULL)
4745 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4746 ignore_msg, authenticated_id);
4751 authenticated_sender = NULL;
4752 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4753 value, host_and_ident(TRUE), ignore_msg);
4756 /* Should only get DEFER or ERROR here. Put back terminator
4757 overrides for error message */
4762 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4769 #ifndef DISABLE_PRDR
4770 case ENV_MAIL_OPT_PRDR:
4772 prdr_requested = TRUE;
4777 case ENV_MAIL_OPT_UTF8:
4778 if (!fl.smtputf8_advertised)
4780 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4781 US"SMTPUTF8 used when not advertised");
4785 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4786 message_smtputf8 = allow_utf8_domains = TRUE;
4787 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4789 int old_pool = store_pool;
4790 store_pool = POOL_PERM;
4791 received_protocol = string_sprintf("utf8%s", received_protocol);
4792 store_pool = old_pool;
4797 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS)
4798 case ENV_MAIL_OPT_REQTLS:
4802 if (!fl.requiretls_advertised)
4804 done = synprot_error(L_smtp_syntax_error, 555, NULL,
4805 US"unadvertised MAIL option: REQUIRETLS");
4809 DEBUG(D_receive) debug_printf("requiretls requested\n");
4810 tls_requiretls = REQUIRETLS_MSG;
4812 r = string_copy_malloc(received_protocol);
4813 if ((t = Ustrrchr(r, 's'))) *t = 'S';
4814 received_protocol = r;
4819 /* No valid option. Stick back the terminator characters and break
4820 the loop. Do the name-terminator second as extract_option sets
4821 value==name when it found no equal-sign.
4822 An error for a malformed address will occur. */
4823 case ENV_MAIL_OPT_NULL:
4831 /* Break out of for loop if switch() had bad argument or
4832 when start of the email address is reached */
4833 if (arg_error) break;
4836 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS)
4837 if (tls_requiretls & REQUIRETLS_MSG)
4839 /* Ensure headers-only bounces whether a RET option was given or not. */
4841 DEBUG(D_receive) if (dsn_ret == dsn_ret_full)
4842 debug_printf("requiretls override: dsn_ret_full -> dsn_ret_hdrs\n");
4843 dsn_ret = dsn_ret_hdrs;
4847 /* If we have passed the threshold for rate limiting, apply the current
4848 delay, and update it for next time, provided this is a limited host. */
4850 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4851 verify_check_host(&smtp_ratelimit_hosts) == OK)
4853 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4854 smtp_delay_mail/1000.0);
4855 millisleep((int)smtp_delay_mail);
4856 smtp_delay_mail *= smtp_rlm_factor;
4857 if (smtp_delay_mail > (double)smtp_rlm_limit)
4858 smtp_delay_mail = (double)smtp_rlm_limit;
4861 /* Now extract the address, first applying any SMTP-time rewriting. The
4862 TRUE flag allows "<>" as a sender address. */
4864 raw_sender = rewrite_existflags & rewrite_smtp
4865 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4866 global_rewrite_rules)
4870 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4875 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4879 sender_address = raw_sender;
4881 /* If there is a configured size limit for mail, check that this message
4882 doesn't exceed it. The check is postponed to this point so that the sender
4885 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4887 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4888 log_write(L_size_reject,
4889 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4890 "message too big: size%s=%d max=%d",
4892 host_and_ident(TRUE),
4893 (message_size == INT_MAX)? ">" : "",
4895 thismessage_size_limit);
4896 sender_address = NULL;
4900 /* Check there is enough space on the disk unless configured not to.
4901 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4902 plus the current message - i.e. we accept the message only if it won't
4903 reduce the space below the threshold. Add 5000 to the size to allow for
4904 overheads such as the Received: line and storing of recipients, etc.
4905 By putting the check here, even when SIZE is not given, it allow VRFY
4906 and EXPN etc. to be used when space is short. */
4908 if (!receive_check_fs(
4909 (smtp_check_spool_space && message_size >= 0)?
4910 message_size + 5000 : 0))
4912 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4913 sender_address = NULL;
4917 /* If sender_address is unqualified, reject it, unless this is a locally
4918 generated message, or the sending host or net is permitted to send
4919 unqualified addresses - typically local machines behaving as MUAs -
4920 in which case just qualify the address. The flag is set above at the start
4921 of the SMTP connection. */
4923 if (!sender_domain && *sender_address)
4924 if (f.allow_unqualified_sender)
4926 sender_domain = Ustrlen(sender_address) + 1;
4927 sender_address = rewrite_address_qualify(sender_address, FALSE);
4928 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4933 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4935 log_write(L_smtp_syntax_error,
4936 LOG_MAIN|LOG_REJECT,
4937 "unqualified sender rejected: <%s> %s%s",
4939 host_and_ident(TRUE),
4941 sender_address = NULL;
4945 /* Apply an ACL check if one is defined, before responding. Afterwards,
4946 when pipelining is not advertised, do another sync check in case the ACL
4947 delayed and the client started sending in the meantime. */
4951 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4952 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4958 if (rc == OK || rc == DISCARD)
4960 BOOL more = pipeline_response();
4963 smtp_printf("%s%s%s", more, US"250 OK",
4964 #ifndef DISABLE_PRDR
4965 prdr_requested ? US", PRDR Requested" : US"",
4972 #ifndef DISABLE_PRDR
4974 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4976 smtp_user_msg(US"250", user_msg);
4978 smtp_delay_rcpt = smtp_rlr_base;
4979 f.recipients_discarded = (rc == DISCARD);
4980 was_rej_mail = FALSE;
4984 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4985 sender_address = NULL;
4990 /* The RCPT command requires an address as an operand. There may be any
4991 number of RCPT commands, specifying multiple recipients. We build them all
4992 into a data structure. The start/end values given by parse_extract_address
4993 are not used, as we keep only the extracted address. */
4998 was_rcpt = fl.rcpt_in_progress = TRUE;
5000 /* There must be a sender address; if the sender was rejected and
5001 pipelining was advertised, we assume the client was pipelining, and do not
5002 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5003 get the same treatment. */
5005 if (sender_address == NULL)
5007 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5009 smtp_printf("503 sender not yet given\r\n", FALSE);
5010 was_rej_mail = TRUE;
5014 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5015 US"sender not yet given");
5016 was_rcpt = FALSE; /* Not a valid RCPT */
5022 /* Check for an operand */
5024 if (smtp_cmd_data[0] == 0)
5026 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5027 US"RCPT must have an address operand");
5032 /* Set the DSN flags orcpt and dsn_flags from the session*/
5036 if (fl.esmtp) for(;;)
5038 uschar *name, *value;
5040 if (!extract_option(&name, &value))
5043 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5045 /* Check whether orcpt has been already set */
5048 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5049 US"ORCPT can be specified once only");
5052 orcpt = string_copy(value);
5053 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5056 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5058 /* Check if the notify flags have been already set */
5061 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5062 US"NOTIFY can be specified once only");
5065 if (strcmpic(value, US"NEVER") == 0)
5066 dsn_flags |= rf_notify_never;
5073 while (*pp != 0 && *pp != ',') pp++;
5074 if (*pp == ',') *pp++ = 0;
5075 if (strcmpic(p, US"SUCCESS") == 0)
5077 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5078 dsn_flags |= rf_notify_success;
5080 else if (strcmpic(p, US"FAILURE") == 0)
5082 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5083 dsn_flags |= rf_notify_failure;
5085 else if (strcmpic(p, US"DELAY") == 0)
5087 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5088 dsn_flags |= rf_notify_delay;
5092 /* Catch any strange values */
5093 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5094 US"Invalid value for NOTIFY parameter");
5099 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5103 /* Unknown option. Stick back the terminator characters and break
5104 the loop. An error for a malformed address will occur. */
5108 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5115 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5116 as a recipient address */
5118 recipient = rewrite_existflags & rewrite_smtp
5119 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5120 global_rewrite_rules)
5123 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5124 &recipient_domain, FALSE)))
5126 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5131 /* If the recipient address is unqualified, reject it, unless this is a
5132 locally generated message. However, unqualified addresses are permitted
5133 from a configured list of hosts and nets - typically when behaving as
5134 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5135 really. The flag is set at the start of the SMTP connection.
5137 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5138 assumed this meant "reserved local part", but the revision of RFC 821 and
5139 friends now makes it absolutely clear that it means *mailbox*. Consequently
5140 we must always qualify this address, regardless. */
5142 if (!recipient_domain)
5143 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5150 /* Check maximum allowed */
5152 if (rcpt_count > recipients_max && recipients_max > 0)
5154 if (recipients_max_reject)
5157 smtp_printf("552 too many recipients\r\n", FALSE);
5159 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5160 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5165 smtp_printf("452 too many recipients\r\n", FALSE);
5167 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5168 "temporarily rejected: sender=<%s> %s", sender_address,
5169 host_and_ident(TRUE));
5176 /* If we have passed the threshold for rate limiting, apply the current
5177 delay, and update it for next time, provided this is a limited host. */
5179 if (rcpt_count > smtp_rlr_threshold &&
5180 verify_check_host(&smtp_ratelimit_hosts) == OK)
5182 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5183 smtp_delay_rcpt/1000.0);
5184 millisleep((int)smtp_delay_rcpt);
5185 smtp_delay_rcpt *= smtp_rlr_factor;
5186 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5187 smtp_delay_rcpt = (double)smtp_rlr_limit;
5190 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5191 for them. Otherwise, check the access control list for this recipient. As
5192 there may be a delay in this, re-check for a synchronization error
5193 afterwards, unless pipelining was advertised. */
5195 if (f.recipients_discarded)
5198 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5200 && !f.smtp_in_pipelining_advertised && !check_sync())
5203 /* The ACL was happy */
5207 BOOL more = pipeline_response();
5210 smtp_user_msg(US"250", user_msg);
5212 smtp_printf("250 Accepted\r\n", more);
5213 receive_add_recipient(recipient, -1);
5215 /* Set the dsn flags in the recipients_list */
5216 recipients_list[recipients_count-1].orcpt = orcpt;
5217 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5219 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5220 recipients_list[recipients_count-1].orcpt,
5221 recipients_list[recipients_count-1].dsn_flags);
5224 /* The recipient was discarded */
5226 else if (rc == DISCARD)
5229 smtp_user_msg(US"250", user_msg);
5231 smtp_printf("250 Accepted\r\n", FALSE);
5234 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5235 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5236 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5237 smtp_cmd_argument, f.recipients_discarded? "MAIL" : "RCPT",
5238 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5241 /* Either the ACL failed the address, or it was deferred. */
5245 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5246 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5251 /* The DATA command is legal only if it follows successful MAIL FROM
5252 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5253 not counted as a protocol error if it follows RCPT (which must have been
5254 rejected if there are no recipients.) This function is complete when a
5255 valid DATA command is encountered.
5257 Note concerning the code used: RFC 2821 says this:
5259 - If there was no MAIL, or no RCPT, command, or all such commands
5260 were rejected, the server MAY return a "command out of sequence"
5261 (503) or "no valid recipients" (554) reply in response to the
5264 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5265 because it is the same whether pipelining is in use or not.
5267 If all the RCPT commands that precede DATA provoked the same error message
5268 (often indicating some kind of system error), it is helpful to include it
5269 with the DATA rejection (an idea suggested by Tony Finch). */
5276 if (chunking_state != CHUNKING_OFFERED)
5278 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5279 US"BDAT command used when CHUNKING not advertised");
5283 /* grab size, endmarker */
5285 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5287 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5288 US"missing size for BDAT command");
5291 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5292 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5293 chunking_data_left = chunking_datasize;
5294 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5295 (int)chunking_state, chunking_data_left);
5297 /* push the current receive_* function on the "stack", and
5298 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5299 functions to do the dirty work. */
5300 lwr_receive_getc = receive_getc;
5301 lwr_receive_getbuf = receive_getbuf;
5302 lwr_receive_ungetc = receive_ungetc;
5304 receive_getc = bdat_getc;
5305 receive_ungetc = bdat_ungetc;
5316 DATA_BDAT: /* Common code for DATA and BDAT */
5317 #ifdef EXPERIMENTAL_PIPE_CONNECT
5318 fl.pipe_connect_acceptable = FALSE;
5320 if (!discarded && recipients_count <= 0)
5322 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5324 uschar *code = US"503";
5325 int len = Ustrlen(rcpt_smtp_response);
5326 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5328 /* Responses from smtp_printf() will have \r\n on the end */
5329 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5330 rcpt_smtp_response[len-2] = 0;
5331 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5333 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5334 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5335 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5337 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5338 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5339 ? US"valid RCPT command must precede DATA"
5340 : US"valid RCPT command must precede BDAT");
5342 if (chunking_state > CHUNKING_OFFERED)
5347 if (toomany && recipients_max_reject)
5349 sender_address = NULL; /* This will allow a new MAIL without RSET */
5350 sender_address_unrewritten = NULL;
5351 smtp_printf("554 Too many recipients\r\n", FALSE);
5355 if (chunking_state > CHUNKING_OFFERED)
5356 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5359 /* If there is an ACL, re-check the synchronization afterwards, since the
5360 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5361 to get the DATA command sent. */
5363 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5367 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5368 f.enable_dollar_recipients = TRUE;
5369 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5371 f.enable_dollar_recipients = FALSE;
5372 if (rc == OK && !check_sync())
5376 { /* Either the ACL failed the address, or it was deferred. */
5377 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5383 smtp_user_msg(US"354", user_msg);
5386 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5390 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5391 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5392 US &on, sizeof(on));
5395 message_ended = END_NOTENDED; /* Indicate in middle of data */
5406 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5407 &start, &end, &recipient_domain, FALSE)))
5409 smtp_printf("501 %s\r\n", FALSE, errmess);
5413 if (!recipient_domain)
5414 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5418 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5419 &user_msg, &log_msg)) != OK)
5420 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5424 address_item * addr = deliver_make_addr(address, FALSE);
5426 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5427 -1, -1, NULL, NULL, NULL))
5430 s = string_sprintf("250 <%s> is deliverable", address);
5434 s = (addr->user_message != NULL)?
5435 string_sprintf("451 <%s> %s", address, addr->user_message) :
5436 string_sprintf("451 Cannot resolve <%s> at this time", address);
5440 s = (addr->user_message != NULL)?
5441 string_sprintf("550 <%s> %s", address, addr->user_message) :
5442 string_sprintf("550 <%s> is not deliverable", address);
5443 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5444 smtp_cmd_argument, host_and_ident(TRUE));
5448 smtp_printf("%s\r\n", FALSE, s);
5456 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5458 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5461 BOOL save_log_testing_mode = f.log_testing_mode;
5462 f.address_test_mode = f.log_testing_mode = TRUE;
5463 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5464 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5466 f.address_test_mode = FALSE;
5467 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5476 if (!fl.tls_advertised)
5478 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5479 US"STARTTLS command used when not advertised");
5483 /* Apply an ACL check if one is defined */
5485 if ( acl_smtp_starttls
5486 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5487 &user_msg, &log_msg)) != OK
5490 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5494 /* RFC 2487 is not clear on when this command may be sent, though it
5495 does state that all information previously obtained from the client
5496 must be discarded if a TLS session is started. It seems reasonable to
5497 do an implied RSET when STARTTLS is received. */
5499 incomplete_transaction_log(US"STARTTLS");
5500 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5501 smtp_reset(reset_point);
5503 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5505 /* There's an attack where more data is read in past the STARTTLS command
5506 before TLS is negotiated, then assumed to be part of the secure session
5507 when used afterwards; we use segregated input buffers, so are not
5508 vulnerable, but we want to note when it happens and, for sheer paranoia,
5509 ensure that the buffer is "wiped".
5510 Pipelining sync checks will normally have protected us too, unless disabled
5511 by configuration. */
5513 if (receive_smtp_buffered())
5516 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5517 if (tls_in.active.sock < 0)
5518 smtp_inend = smtp_inptr = smtp_inbuffer;
5519 /* and if TLS is already active, tls_server_start() should fail */
5522 /* There is nothing we value in the input buffer and if TLS is successfully
5523 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5524 fresh content into it. The buffer contains arbitrary content from an
5525 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5526 It seems safest to just wipe away the content rather than leave it as a
5527 target to jump to. */
5529 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5531 /* Attempt to start up a TLS session, and if successful, discard all
5532 knowledge that was obtained previously. At least, that's what the RFC says,
5533 and that's what happens by default. However, in order to work round YAEB,
5534 there is an option to remember the esmtp state. Sigh.
5536 We must allow for an extra EHLO command and an extra AUTH command after
5537 STARTTLS that don't add to the nonmail command count. */
5540 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5542 if (!tls_remember_esmtp)
5543 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5544 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5545 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5546 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5547 if (sender_helo_name)
5549 store_free(sender_helo_name);
5550 sender_helo_name = NULL;
5551 host_build_sender_fullhost(); /* Rebuild */
5552 set_process_info("handling incoming TLS connection from %s",
5553 host_and_ident(FALSE));
5556 (sender_host_address ? protocols : protocols_local)
5558 ? pextend + (sender_host_authenticated ? pauthed : 0)
5560 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5563 sender_host_auth_pubname = sender_host_authenticated = NULL;
5564 authenticated_id = NULL;
5565 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5566 DEBUG(D_tls) debug_printf("TLS active\n");
5567 break; /* Successful STARTTLS */
5570 (void) smtp_log_tls_fail(s);
5572 /* Some local configuration problem was discovered before actually trying
5573 to do a TLS handshake; give a temporary error. */
5577 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5581 /* Hard failure. Reject everything except QUIT or closed connection. One
5582 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5583 set, but we must still reject all incoming commands. Another is a handshake
5584 failure - and there may some encrypted data still in the pipe to us, which we
5585 see as garbage commands. */
5587 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5588 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5591 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5592 smtp_get_connection_info());
5593 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5597 /* It is perhaps arguable as to which exit ACL should be called here,
5598 but as it is probably a situation that almost never arises, it
5599 probably doesn't matter. We choose to call the real QUIT ACL, which in
5600 some sense is perhaps "right". */
5605 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5606 &log_msg)) == ERROR))
5607 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5610 smtp_respond(US"221", 3, TRUE, user_msg);
5612 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5613 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5614 smtp_get_connection_info());
5619 smtp_printf("554 Security failure\r\n", FALSE);
5622 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5627 /* The ACL for QUIT is provided for gathering statistical information or
5628 similar; it does not affect the response code, but it can supply a custom
5632 smtp_quit_handler(&user_msg, &log_msg);
5638 smtp_rset_handler();
5639 cancel_cutthrough_connection(TRUE, US"RSET received");
5640 smtp_reset(reset_point);
5647 smtp_printf("250 OK\r\n", FALSE);
5651 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5652 used, a check will be done for permitted hosts. Show STARTTLS only if not
5653 already in a TLS session and if it would be advertised in the EHLO
5658 smtp_printf("214-Commands supported:\r\n", TRUE);
5662 Ustrcat(buffer, " AUTH");
5664 if (tls_in.active.sock < 0 &&
5665 verify_check_host(&tls_advertise_hosts) != FAIL)
5666 Ustrcat(buffer, " STARTTLS");
5668 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5669 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5670 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5671 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5672 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5673 smtp_printf("214%s\r\n", FALSE, buffer);
5679 incomplete_transaction_log(US"connection lost");
5680 smtp_notquit_exit(US"connection-lost", US"421",
5681 US"%s lost input connection", smtp_active_hostname);
5683 /* Don't log by default unless in the middle of a message, as some mailers
5684 just drop the call rather than sending QUIT, and it clutters up the logs.
5687 if (sender_address || recipients_count > 0)
5688 log_write(L_lost_incoming_connection, LOG_MAIN,
5689 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5690 f.sender_host_unknown ? "EOF" : "disconnection",
5691 f.tcp_in_fastopen_logged
5694 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5696 host_and_ident(FALSE), smtp_read_error,
5697 string_timesince(&smtp_connection_start)
5701 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5702 smtp_get_connection_info(),
5703 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5705 string_timesince(&smtp_connection_start)
5716 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5717 US"ETRN is not permitted inside a transaction");
5721 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5722 host_and_ident(FALSE));
5724 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5725 &user_msg, &log_msg)) != OK)
5727 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5731 /* Compute the serialization key for this command. */
5733 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5735 /* If a command has been specified for running as a result of ETRN, we
5736 permit any argument to ETRN. If not, only the # standard form is permitted,
5737 since that is strictly the only kind of ETRN that can be implemented
5738 according to the RFC. */
5740 if (smtp_etrn_command)
5744 etrn_command = smtp_etrn_command;
5745 deliver_domain = smtp_cmd_data;
5746 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5747 US"ETRN processing", &error);
5748 deliver_domain = NULL;
5751 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5753 smtp_printf("458 Internal failure\r\n", FALSE);
5758 /* Else set up to call Exim with the -R option. */
5762 if (*smtp_cmd_data++ != '#')
5764 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5765 US"argument must begin with #");
5768 etrn_command = US"exim -R";
5769 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5770 *queue_name ? 4 : 2,
5771 US"-R", smtp_cmd_data,
5772 US"-MCG", queue_name);
5775 /* If we are host-testing, don't actually do anything. */
5781 debug_printf("ETRN command is: %s\n", etrn_command);
5782 debug_printf("ETRN command execution skipped\n");
5784 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5785 else smtp_user_msg(US"250", user_msg);
5790 /* If ETRN queue runs are to be serialized, check the database to
5791 ensure one isn't already running. */
5793 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5795 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5799 /* Fork a child process and run the command. We don't want to have to
5800 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5801 forking. It should be set that way anyway for external incoming SMTP,
5802 but we save and restore to be tidy. If serialization is required, we
5803 actually run the command in yet another process, so we can wait for it
5804 to complete and then remove the serialization lock. */
5806 oldsignal = signal(SIGCHLD, SIG_IGN);
5808 if ((pid = fork()) == 0)
5810 smtp_input = FALSE; /* This process is not associated with the */
5811 (void)fclose(smtp_in); /* SMTP call any more. */
5812 (void)fclose(smtp_out);
5814 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5816 /* If not serializing, do the exec right away. Otherwise, fork down
5817 into another process. */
5819 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5821 DEBUG(D_exec) debug_print_argv(argv);
5822 exim_nullstd(); /* Ensure std{in,out,err} exist */
5823 execv(CS argv[0], (char *const *)argv);
5824 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5825 etrn_command, strerror(errno));
5826 _exit(EXIT_FAILURE); /* paranoia */
5829 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5830 is, we are in the first subprocess, after forking again. All we can do
5831 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5832 complete, before removing the serialization. */
5835 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5836 "failed: %s", strerror(errno));
5840 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5842 (void)wait(&status);
5843 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5847 enq_end(etrn_serialize_key);
5848 _exit(EXIT_SUCCESS);
5851 /* Back in the top level SMTP process. Check that we started a subprocess
5852 and restore the signal state. */
5856 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5858 smtp_printf("458 Unable to fork process\r\n", FALSE);
5859 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5863 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5864 else smtp_user_msg(US"250", user_msg);
5867 signal(SIGCHLD, oldsignal);
5872 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5873 US"unexpected argument data");
5877 /* This currently happens only for NULLs, but could be extended. */
5880 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5881 US"NUL character(s) present (shown as '?')");
5882 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5889 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5890 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5891 c = smtp_inend - smtp_inptr;
5892 if (c > 150) c = 150; /* limit logged amount */
5894 incomplete_transaction_log(US"sync failure");
5895 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5896 "(next input sent too soon: pipelining was%s advertised): "
5897 "rejected \"%s\" %s next input=\"%s\"",
5898 f.smtp_in_pipelining_advertised ? "" : " not",
5899 smtp_cmd_buffer, host_and_ident(TRUE),
5900 string_printing(smtp_inptr));
5901 smtp_notquit_exit(US"synchronization-error", US"554",
5902 US"SMTP synchronization error");
5903 done = 1; /* Pretend eof - drops connection */
5907 case TOO_MANY_NONMAIL_CMD:
5908 s = smtp_cmd_buffer;
5909 while (*s != 0 && !isspace(*s)) s++;
5910 incomplete_transaction_log(US"too many non-mail commands");
5911 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5912 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5913 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5914 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5915 done = 1; /* Pretend eof - drops connection */
5918 #ifdef SUPPORT_PROXY
5919 case PROXY_FAIL_IGNORE_CMD:
5920 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5925 if (unknown_command_count++ >= smtp_max_unknown_commands)
5927 log_write(L_smtp_syntax_error, LOG_MAIN,
5928 "SMTP syntax error in \"%s\" %s %s",
5929 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5930 US"unrecognized command");
5931 incomplete_transaction_log(US"unrecognized command");
5932 smtp_notquit_exit(US"bad-commands", US"500",
5933 US"Too many unrecognized commands");
5935 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5936 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5937 string_printing(smtp_cmd_buffer));
5940 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5941 US"unrecognized command");
5945 /* This label is used by goto's inside loops that want to break out to
5946 the end of the command-processing loop. */
5949 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5950 last_was_rcpt = was_rcpt; /* protocol error handling */
5954 return done - 2; /* Convert yield values */
5960 authres_smtpauth(gstring * g)
5962 if (!sender_host_authenticated)
5965 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5967 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5968 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5969 else if (authenticated_id)
5970 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5972 g = string_catn(g, US") reason=x509.auth", 17);
5974 if (authenticated_sender)
5975 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5983 /* End of smtp_in.c */