1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2017 */
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 *************************************************/
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
137 static BOOL tls_advertised;
139 static BOOL dsn_advertised;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
152 static BOOL smtputf8_advertised;
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
193 /* If you change anything above here, also fix the definitions below. */
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
220 static uschar *smtp_names[] =
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
234 static uschar *protocols[] = {
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
306 /* forward declarations */
307 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Such checks can in any case only be
318 done when TLS is not in use. Normally, the checks happen when commands are
319 read: Exim ensures that there is no more input in the input buffer. In normal
320 cases, the response to the command will be fast, and there is no further check.
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
328 When there is unwanted input, we read it so that it appears in the log of the
332 Returns: TRUE if all is well; FALSE if there is input pending
340 struct timeval tzero;
342 if (!smtp_enforce_sync || sender_host_address == NULL ||
343 sender_host_notsocket || tls_in.active >= 0)
346 fd = fileno(smtp_in);
351 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
353 if (rc <= 0) return TRUE; /* Not ready to read */
354 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
355 if (rc < 0) return TRUE; /* End of file or error */
358 rc = smtp_inend - smtp_inptr;
359 if (rc > 150) rc = 150;
366 /*************************************************
367 * Log incomplete transactions *
368 *************************************************/
370 /* This function is called after a transaction has been aborted by RSET, QUIT,
371 connection drops or other errors. It logs the envelope information received
372 so far in order to preserve address verification attempts.
374 Argument: string to indicate what aborted the transaction
379 incomplete_transaction_log(uschar *what)
381 if (sender_address == NULL || /* No transaction in progress */
382 !LOGGING(smtp_incomplete_transaction))
385 /* Build list of recipients for logging */
387 if (recipients_count > 0)
390 raw_recipients = store_get(recipients_count * sizeof(uschar *));
391 for (i = 0; i < recipients_count; i++)
392 raw_recipients[i] = recipients_list[i].address;
393 raw_recipients_count = recipients_count;
396 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
397 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
403 /*************************************************
404 * SMTP version of getc() *
405 *************************************************/
407 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
408 it flushes the output, and refills the buffer, with a timeout. The signal
409 handler is set appropriately by the calling function. This function is not used
410 after a connection has negotiated itself into an TLS/SSL state.
412 Arguments: lim Maximum amount to read/buffer
413 Returns: the next character or EOF
417 smtp_getc(unsigned lim)
419 if (smtp_inptr >= smtp_inend)
422 if (!smtp_out) return EOF;
424 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
426 /* Limit amount read, so non-message data is not fed to DKIM */
428 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
433 /* Must put the error text in fixed store, because this might be during
434 header reading, where it releases unused store above the header. */
437 smtp_had_error = save_errno;
438 smtp_read_error = string_copy_malloc(
439 string_sprintf(" (error: %s)", strerror(save_errno)));
441 else smtp_had_eof = 1;
445 dkim_exim_verify_feed(smtp_inbuffer, rc);
447 smtp_inend = smtp_inbuffer + rc;
448 smtp_inptr = smtp_inbuffer;
450 return *smtp_inptr++;
457 int n = smtp_inend - smtp_inptr;
459 dkim_exim_verify_feed(smtp_inptr, n);
464 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
465 previous BDAT chunk and getting new ones when we run out. Uses the
466 underlying smtp_getc or tls_getc both for that and for getting the
467 (buffered) data byte. EOD signals (an expected) no further data.
468 ERR signals a protocol error, and EOF a closed input stream.
470 Called from read_bdat_smtp() in receive.c for the message body, but also
471 by the headers read loop in receive_msg(); manipulates chunking_state
472 to handle the BDAT command/response.
473 Placed here due to the correlation with the above smtp_getc(), which it wraps,
474 and also by the need to do smtp command/response handling.
476 Arguments: lim (ignored)
477 Returns: the next character or ERR, EOD or EOF
481 bdat_getc(unsigned lim)
483 uschar * user_msg = NULL;
492 if (chunking_data_left > 0)
493 return lwr_receive_getc(chunking_data_left--);
495 receive_getc = lwr_receive_getc;
496 receive_ungetc = lwr_receive_ungetc;
498 dkim_save = dkim_collect_input;
499 dkim_collect_input = FALSE;
502 /* Unless PIPELINING was offered, there should be no next command
503 until after we ack that chunk */
505 if (!pipelining_advertised && !check_sync())
507 incomplete_transaction_log(US"sync failure");
508 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
509 "(next input sent too soon: pipelining was not advertised): "
510 "rejected \"%s\" %s next input=\"%s\"",
511 smtp_cmd_buffer, host_and_ident(TRUE),
512 string_printing(smtp_inptr));
513 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
514 US"SMTP synchronization error");
515 goto repeat_until_rset;
518 /* If not the last, ack the received chunk. The last response is delayed
519 until after the data ACL decides on it */
521 if (chunking_state == CHUNKING_LAST)
524 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
529 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
530 chunking_state = CHUNKING_OFFERED;
531 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
533 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
534 QUIT, RSET or NOOP but handling them seems obvious */
537 switch(smtp_read_command(TRUE, 1))
540 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
541 US"only BDAT permissible after non-LAST BDAT");
544 switch(smtp_read_command(TRUE, 1))
546 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
547 case EOF_CMD: return EOF;
548 case RSET_CMD: smtp_rset_handler(); return ERR;
549 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
550 US"only RSET accepted now") > 0)
552 goto repeat_until_rset;
556 smtp_quit_handler(&user_msg, &log_msg);
567 smtp_printf("250 OK\r\n");
574 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
576 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
577 US"missing size for BDAT command");
580 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
581 ? CHUNKING_LAST : CHUNKING_ACTIVE;
582 chunking_data_left = chunking_datasize;
583 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
584 (int)chunking_state, chunking_data_left);
586 if (chunking_datasize == 0)
587 if (chunking_state == CHUNKING_LAST)
591 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
592 US"zero size for BDAT command");
593 goto repeat_until_rset;
596 receive_getc = bdat_getc;
597 receive_ungetc = bdat_ungetc;
599 dkim_collect_input = dkim_save;
601 break; /* to top of main loop */
608 bdat_flush_data(void)
610 while (chunking_data_left > 0)
611 if (lwr_receive_getc(chunking_data_left--) < 0)
614 receive_getc = lwr_receive_getc;
615 receive_ungetc = lwr_receive_ungetc;
617 if (chunking_state != CHUNKING_LAST)
619 chunking_state = CHUNKING_OFFERED;
620 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
627 /*************************************************
628 * SMTP version of ungetc() *
629 *************************************************/
631 /* Puts a character back in the input buffer. Only ever
637 Returns: the character
651 chunking_data_left++;
652 return lwr_receive_ungetc(ch);
657 /*************************************************
658 * SMTP version of feof() *
659 *************************************************/
661 /* Tests for a previous EOF
664 Returns: non-zero if the eof flag is set
676 /*************************************************
677 * SMTP version of ferror() *
678 *************************************************/
680 /* Tests for a previous read error, and returns with errno
681 restored to what it was when the error was detected.
684 Returns: non-zero if the error flag is set
690 errno = smtp_had_error;
691 return smtp_had_error;
696 /*************************************************
697 * Test for characters in the SMTP buffer *
698 *************************************************/
700 /* Used at the end of a message
709 return smtp_inptr < smtp_inend;
714 /*************************************************
715 * Write formatted string to SMTP channel *
716 *************************************************/
718 /* This is a separate function so that we don't have to repeat everything for
719 TLS support or debugging. It is global so that the daemon and the
720 authentication functions can use it. It does not return any error indication,
721 because major problems such as dropped connections won't show up till an output
722 flush for non-TLS connections. The smtp_fflush() function is available for
723 checking that: for convenience, TLS output errors are remembered here so that
724 they are also picked up later by smtp_fflush().
728 ... optional arguments
734 smtp_printf(const char *format, ...)
738 va_start(ap, format);
739 smtp_vprintf(format, ap);
743 /* This is split off so that verify.c:respond_printf() can, in effect, call
744 smtp_printf(), bearing in mind that in C a vararg function can't directly
745 call another vararg function, only a function which accepts a va_list. */
748 smtp_vprintf(const char *format, va_list ap)
752 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
756 void *reset_point = store_get(0);
757 uschar *msg_copy, *cr, *end;
758 msg_copy = string_copy(big_buffer);
759 end = msg_copy + Ustrlen(msg_copy);
760 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
761 memmove(cr, cr + 1, (end--) - cr);
762 debug_printf("SMTP>> %s", msg_copy);
763 store_reset(reset_point);
768 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
769 smtp_closedown(US"Unexpected error");
770 exim_exit(EXIT_FAILURE);
773 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
774 have had the same. Note: this code is also present in smtp_respond(). It would
775 be tidier to have it only in one place, but when it was added, it was easier to
776 do it that way, so as not to have to mess with the code for the RCPT command,
777 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
779 if (rcpt_in_progress)
781 if (rcpt_smtp_response == NULL)
782 rcpt_smtp_response = string_copy(big_buffer);
783 else if (rcpt_smtp_response_same &&
784 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
785 rcpt_smtp_response_same = FALSE;
786 rcpt_in_progress = FALSE;
789 /* Now write the string */
792 if (tls_in.active >= 0)
794 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
795 smtp_write_error = -1;
800 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
805 /*************************************************
806 * Flush SMTP out and check for error *
807 *************************************************/
809 /* This function isn't currently used within Exim (it detects errors when it
810 tries to read the next SMTP input), but is available for use in local_scan().
811 For non-TLS connections, it flushes the output and checks for errors. For
812 TLS-connections, it checks for a previously-detected TLS write error.
815 Returns: 0 for no error; -1 after an error
821 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
822 return smtp_write_error;
827 /*************************************************
828 * SMTP command read timeout *
829 *************************************************/
831 /* Signal handler for timing out incoming SMTP commands. This attempts to
834 Argument: signal number (SIGALRM)
839 command_timeout_handler(int sig)
841 sig = sig; /* Keep picky compilers happy */
842 log_write(L_lost_incoming_connection,
843 LOG_MAIN, "SMTP command timeout on%s connection from %s",
844 (tls_in.active >= 0)? " TLS" : "",
845 host_and_ident(FALSE));
846 if (smtp_batched_input)
847 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
848 smtp_notquit_exit(US"command-timeout", US"421",
849 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
850 exim_exit(EXIT_FAILURE);
855 /*************************************************
857 *************************************************/
859 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
861 Argument: signal number (SIGTERM)
866 command_sigterm_handler(int sig)
868 sig = sig; /* Keep picky compilers happy */
869 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
870 if (smtp_batched_input)
871 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
872 smtp_notquit_exit(US"signal-exit", US"421",
873 US"%s: Service not available - closing connection", smtp_active_hostname);
874 exim_exit(EXIT_FAILURE);
881 /*************************************************
882 * Restore socket timeout to previous value *
883 *************************************************/
884 /* If the previous value was successfully retrieved, restore
885 it before returning control to the non-proxy routines
887 Arguments: fd - File descriptor for input
888 get_ok - Successfully retrieved previous values
889 tvtmp - Time struct with previous values
890 vslen - Length of time struct
894 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
897 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
900 /*************************************************
901 * Check if host is required proxy host *
902 *************************************************/
903 /* The function determines if inbound host will be a regular smtp host
904 or if it is configured that it must use Proxy Protocol. A local
912 check_proxy_protocol_host()
916 if ( sender_host_address
917 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
918 sender_host_address, NULL)) == OK)
921 debug_printf("Detected proxy protocol configured host\n");
922 proxy_session = TRUE;
924 return proxy_session;
928 /*************************************************
929 * Read data until newline or end of buffer *
930 *************************************************/
931 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
932 read an entire buffer and assume there will be nothing past a proxy protocol
933 header. Our approach normally is to use stdio, but again that relies upon
934 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
935 reading _nothing_ before client TLS handshake. So we don't want to use the
936 usual buffering reads which may read enough to block TLS starting.
938 So unfortunately we're down to "read one byte at a time, with a syscall each,
939 and expect a little overhead", for all proxy-opened connections which are v1,
940 just to handle the TLS-on-connect case. Since SSL functions wrap the
941 underlying fd, we can't assume that we can feed them any already-read content.
943 We need to know where to read to, the max capacity, and we'll read until we
944 get a CR and one more character. Let the caller scream if it's CR+!LF.
946 Return the amount read.
950 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
952 uschar *to = base + already;
958 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
959 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
960 cr = memchr(base, '\r', already);
963 if ((cr - base) < already - 1)
965 /* \r and presumed \n already within what we have; probably not
966 actually proxy protocol, but abort cleanly. */
969 /* \r is last character read, just need one more. */
975 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
986 // reached end without having room for a final newline, abort
991 /*************************************************
992 * Setup host for proxy protocol *
993 *************************************************/
994 /* The function configures the connection based on a header from the
995 inbound host to use Proxy Protocol. The specification is very exact
996 so exit with an error if do not find the exact required pieces. This
997 includes an incorrect number of spaces separating args.
1000 Returns: Boolean success
1004 setup_proxy_protocol_host()
1016 struct { /* TCP/UDP over IPv4, len = 12 */
1022 struct { /* TCP/UDP over IPv6, len = 36 */
1023 uint8_t src_addr[16];
1024 uint8_t dst_addr[16];
1028 struct { /* AF_UNIX sockets, len = 216 */
1029 uschar src_addr[108];
1030 uschar dst_addr[108];
1036 /* Temp variables used in PPv2 address:port parsing */
1038 char tmpip[INET_ADDRSTRLEN];
1039 struct sockaddr_in tmpaddr;
1040 char tmpip6[INET6_ADDRSTRLEN];
1041 struct sockaddr_in6 tmpaddr6;
1043 /* We can't read "all data until end" because while SMTP is
1044 server-speaks-first, the TLS handshake is client-speaks-first, so for
1045 TLS-on-connect ports the proxy protocol header will usually be immediately
1046 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1047 reinject data for reading by those. So instead we first read "enough to be
1048 safely read within the header, and figure out how much more to read".
1049 For v1 we will later read to the end-of-line, for v2 we will read based upon
1052 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1053 data is needed total. For v1, where the line looks like:
1054 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1056 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1057 We seem to support that. So, if we read 14 octets then we can tell if we're
1058 v2 or v1. If we're v1, we can continue reading as normal.
1060 If we're v2, we can't slurp up the entire header. We need the length in the
1061 15th & 16th octets, then to read everything after that.
1063 So to safely handle v1 and v2, with client-sent-first supported correctly,
1064 we have to do a minimum of 3 read calls, not 1. Eww.
1067 #define PROXY_INITIAL_READ 14
1068 #define PROXY_V2_HEADER_SIZE 16
1069 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1070 # error Code bug in sizes of data to read for proxy usage
1075 int fd = fileno(smtp_in);
1076 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1077 uschar * iptype; /* To display debug info */
1079 struct timeval tvtmp;
1080 socklen_t vslen = sizeof(struct timeval);
1083 /* Save current socket timeout values */
1084 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1086 /* Proxy Protocol host must send header within a short time
1087 (default 3 seconds) or it's considered invalid */
1088 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1089 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1090 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1095 /* The inbound host was declared to be a Proxy Protocol host, so
1096 don't do a PEEK into the data, actually slurp up enough to be
1097 "safe". Can't take it all because TLS-on-connect clients follow
1098 immediately with TLS handshake. */
1099 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1101 while (ret == -1 && errno == EINTR);
1106 /* For v2, handle reading the length, and then the rest. */
1107 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1112 /* First get the length fields. */
1115 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1116 } while (retmore == -1 && errno == EINTR);
1121 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1123 /* May 2014: haproxy combined the version and command into one byte to
1124 allow two full bytes for the length field in order to proxy SSL
1125 connections. SSL Proxy is not supported in this version of Exim, but
1126 must still separate values here. */
1130 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1134 /* The v2 header will always be 16 bytes per the spec. */
1135 size = 16 + ntohs(hdr.v2.len);
1136 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1137 size, (int)sizeof(hdr));
1139 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1140 amount that we need. Double-check that the size is not unreasonable, then
1142 if (size > sizeof(hdr))
1144 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1152 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1153 } while (retmore == -1 && errno == EINTR);
1157 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1158 } while (ret < size);
1160 } /* end scope for getting rest of data for v2 */
1162 /* At this point: if PROXYv2, we've read the exact size required for all data;
1163 if PROXYv1 then we've read "less than required for any valid line" and should
1166 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1168 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1172 case 0x01: /* PROXY command */
1175 case 0x11: /* TCPv4 address type */
1177 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1178 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1179 if (!string_is_ip_address(US tmpip, NULL))
1181 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1184 proxy_local_address = sender_host_address;
1185 sender_host_address = string_copy(US tmpip);
1186 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1187 proxy_local_port = sender_host_port;
1188 sender_host_port = tmpport;
1189 /* Save dest ip/port */
1190 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1191 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1192 if (!string_is_ip_address(US tmpip, NULL))
1194 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1197 proxy_external_address = string_copy(US tmpip);
1198 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1199 proxy_external_port = tmpport;
1201 case 0x21: /* TCPv6 address type */
1203 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1204 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1205 if (!string_is_ip_address(US tmpip6, NULL))
1207 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1210 proxy_local_address = sender_host_address;
1211 sender_host_address = string_copy(US tmpip6);
1212 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1213 proxy_local_port = sender_host_port;
1214 sender_host_port = tmpport;
1215 /* Save dest ip/port */
1216 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1217 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1218 if (!string_is_ip_address(US tmpip6, NULL))
1220 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1223 proxy_external_address = string_copy(US tmpip6);
1224 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1225 proxy_external_port = tmpport;
1229 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1233 /* Unsupported protocol, keep local connection address */
1235 case 0x00: /* LOCAL command */
1236 /* Keep local connection address for LOCAL */
1241 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1245 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1249 uschar *sp; /* Utility variables follow */
1254 /* get the rest of the line */
1255 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1260 p = string_copy(hdr.v1.line);
1261 end = memchr(p, '\r', ret - 1);
1263 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1265 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1268 *end = '\0'; /* Terminate the string */
1269 size = end + 2 - p; /* Skip header + CRLF */
1270 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1271 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1272 /* Step through the string looking for the required fields. Ensure
1273 strict adherence to required formatting, exit for any error. */
1275 if (!isspace(*(p++)))
1277 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1280 if (!Ustrncmp(p, CCS"TCP4", 4))
1282 else if (!Ustrncmp(p,CCS"TCP6", 4))
1284 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1286 iptype = US"Unknown";
1291 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1295 p += Ustrlen(iptype);
1296 if (!isspace(*(p++)))
1298 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1301 /* Find the end of the arg */
1302 if ((sp = Ustrchr(p, ' ')) == NULL)
1305 debug_printf("Did not find proxied src %s\n", iptype);
1309 if(!string_is_ip_address(p, NULL))
1312 debug_printf("Proxied src arg is not an %s address\n", iptype);
1315 proxy_local_address = sender_host_address;
1316 sender_host_address = p;
1318 if ((sp = Ustrchr(p, ' ')) == NULL)
1321 debug_printf("Did not find proxy dest %s\n", iptype);
1325 if(!string_is_ip_address(p, NULL))
1328 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1331 proxy_external_address = p;
1333 if ((sp = Ustrchr(p, ' ')) == NULL)
1335 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1339 tmp_port = strtol(CCS p, &endc, 10);
1340 if (*endc || tmp_port == 0)
1343 debug_printf("Proxied src port '%s' not an integer\n", p);
1346 proxy_local_port = sender_host_port;
1347 sender_host_port = tmp_port;
1349 if ((sp = Ustrchr(p, '\0')) == NULL)
1351 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1354 tmp_port = strtol(CCS p, &endc, 10);
1355 if (*endc || tmp_port == 0)
1358 debug_printf("Proxy dest port '%s' not an integer\n", p);
1361 proxy_external_port = tmp_port;
1362 /* Already checked for /r /n above. Good V1 header received. */
1366 /* Wrong protocol */
1367 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1368 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1374 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1375 yield = proxy_session;
1377 /* Don't flush any potential buffer contents. Any input on proxyfail
1378 should cause a synchronization failure */
1381 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1386 sender_host_name = NULL;
1387 (void) host_name_lookup();
1388 host_build_sender_fullhost();
1392 proxy_session_failed = TRUE;
1394 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1401 /*************************************************
1402 * Read one command line *
1403 *************************************************/
1405 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1406 There are sites that don't do this, and in any case internal SMTP probably
1407 should check only for LF. Consequently, we check here for LF only. The line
1408 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1409 an unknown command. The command is read into the global smtp_cmd_buffer so that
1410 it is available via $smtp_command.
1412 The character reading routine sets up a timeout for each block actually read
1413 from the input (which may contain more than one command). We set up a special
1414 signal handler that closes down the session on a timeout. Control does not
1415 return when it runs.
1418 check_sync if TRUE, check synchronization rules if global option is TRUE
1419 buffer_lim maximum to buffer in lower layer
1421 Returns: a code identifying the command (enumerated above)
1425 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1430 BOOL hadnull = FALSE;
1432 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1434 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1436 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1438 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1446 smtp_cmd_buffer[ptr++] = c;
1449 receive_linecount++; /* For BSMTP errors */
1450 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1452 /* If hit end of file, return pseudo EOF command. Whether we have a
1453 part-line already read doesn't matter, since this is an error state. */
1455 if (c == EOF) return EOF_CMD;
1457 /* Remove any CR and white space at the end of the line, and terminate the
1460 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1461 smtp_cmd_buffer[ptr] = 0;
1463 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1465 /* NULLs are not allowed in SMTP commands */
1467 if (hadnull) return BADCHAR_CMD;
1469 /* Scan command list and return identity, having set the data pointer
1470 to the start of the actual data characters. Check for SMTP synchronization
1473 for (p = cmd_list; p < cmd_list_end; p++)
1475 #ifdef SUPPORT_PROXY
1476 /* Only allow QUIT command if Proxy Protocol parsing failed */
1477 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1481 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1482 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1483 || smtp_cmd_buffer[p->len] == 0
1484 || smtp_cmd_buffer[p->len] == ' '
1487 if (smtp_inptr < smtp_inend && /* Outstanding input */
1488 p->cmd < sync_cmd_limit && /* Command should sync */
1489 check_sync && /* Local flag set */
1490 smtp_enforce_sync && /* Global flag set */
1491 sender_host_address != NULL && /* Not local input */
1492 !sender_host_notsocket) /* Really is a socket */
1495 /* The variables $smtp_command and $smtp_command_argument point into the
1496 unmodified input buffer. A copy of the latter is taken for actual
1497 processing, so that it can be chopped up into separate parts if necessary,
1498 for example, when processing a MAIL command options such as SIZE that can
1499 follow the sender address. */
1501 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1502 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1503 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1504 smtp_cmd_data = smtp_data_buffer;
1506 /* Count non-mail commands from those hosts that are controlled in this
1507 way. The default is all hosts. We don't waste effort checking the list
1508 until we get a non-mail command, but then cache the result to save checking
1509 again. If there's a DEFER while checking the host, assume it's in the list.
1511 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1512 start of each incoming message by fiddling with the value in the table. */
1514 if (!p->is_mail_cmd)
1516 if (count_nonmail == TRUE_UNSET) count_nonmail =
1517 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1518 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1519 return TOO_MANY_NONMAIL_CMD;
1522 /* If there is data for a command that does not expect it, generate the
1525 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1529 #ifdef SUPPORT_PROXY
1530 /* Only allow QUIT command if Proxy Protocol parsing failed */
1531 if (proxy_session && proxy_session_failed)
1532 return PROXY_FAIL_IGNORE_CMD;
1535 /* Enforce synchronization for unknown commands */
1537 if (smtp_inptr < smtp_inend && /* Outstanding input */
1538 check_sync && /* Local flag set */
1539 smtp_enforce_sync && /* Global flag set */
1540 sender_host_address != NULL && /* Not local input */
1541 !sender_host_notsocket) /* Really is a socket */
1549 /*************************************************
1550 * Forced closedown of call *
1551 *************************************************/
1553 /* This function is called from log.c when Exim is dying because of a serious
1554 disaster, and also from some other places. If an incoming non-batched SMTP
1555 channel is open, it swallows the rest of the incoming message if in the DATA
1556 phase, sends the reply string, and gives an error to all subsequent commands
1557 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1561 message SMTP reply string to send, excluding the code
1567 smtp_closedown(uschar *message)
1569 if (smtp_in == NULL || smtp_batched_input) return;
1570 receive_swallow_smtp();
1571 smtp_printf("421 %s\r\n", message);
1573 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1579 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1584 smtp_printf("250 Reset OK\r\n");
1588 smtp_printf("421 %s\r\n", message);
1596 /*************************************************
1597 * Set up connection info for logging *
1598 *************************************************/
1600 /* This function is called when logging information about an SMTP connection.
1601 It sets up appropriate source information, depending on the type of connection.
1602 If sender_fullhost is NULL, we are at a very early stage of the connection;
1603 just use the IP address.
1606 Returns: a string describing the connection
1610 smtp_get_connection_info(void)
1612 const uschar * hostname = sender_fullhost
1613 ? sender_fullhost : sender_host_address;
1616 return string_sprintf("SMTP connection from %s", hostname);
1618 if (sender_host_unknown || sender_host_notsocket)
1619 return string_sprintf("SMTP connection from %s", sender_ident);
1622 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1624 if (LOGGING(incoming_interface) && interface_address != NULL)
1625 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1626 interface_address, interface_port);
1628 return string_sprintf("SMTP connection from %s", hostname);
1634 /* Append TLS-related information to a log line
1637 s String under construction: allocated string to extend, or NULL
1638 sizep Pointer to current allocation size (update on return), or NULL
1639 ptrp Pointer to index for new entries in string (update on return), or NULL
1641 Returns: Allocated string or NULL
1644 s_tlslog(uschar * s, int * sizep, int * ptrp)
1646 int size = sizep ? *sizep : 0;
1647 int ptr = ptrp ? *ptrp : 0;
1649 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1650 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1651 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1652 s = string_append(s, &size, &ptr, 2, US" CV=",
1653 tls_in.certificate_verified? "yes":"no");
1654 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1655 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1656 string_printing(tls_in.peerdn), US"\"");
1657 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1658 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1659 string_printing(tls_in.sni), US"\"");
1664 if (sizep) *sizep = size;
1665 if (ptrp) *ptrp = ptr;
1671 /*************************************************
1672 * Log lack of MAIL if so configured *
1673 *************************************************/
1675 /* This function is called when an SMTP session ends. If the log selector
1676 smtp_no_mail is set, write a log line giving some details of what has happened
1677 in the SMTP session.
1684 smtp_log_no_mail(void)
1689 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1695 if (sender_host_authenticated != NULL)
1697 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1698 if (authenticated_id != NULL)
1699 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1703 s = s_tlslog(s, &size, &ptr);
1706 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1707 US" C=..." : US" C=";
1708 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1710 if (smtp_connection_had[i] != SCH_NONE)
1712 s = string_append(s, &size, &ptr, 2, sep,
1713 smtp_names[smtp_connection_had[i]]);
1718 for (i = 0; i < smtp_ch_index; i++)
1720 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1724 if (s != NULL) s[ptr] = 0; else s = US"";
1725 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1726 host_and_ident(FALSE),
1727 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1733 /*************************************************
1734 * Check HELO line and set sender_helo_name *
1735 *************************************************/
1737 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1738 the domain name of the sending host, or an ip literal in square brackets. The
1739 argument is placed in sender_helo_name, which is in malloc store, because it
1740 must persist over multiple incoming messages. If helo_accept_junk is set, this
1741 host is permitted to send any old junk (needed for some broken hosts).
1742 Otherwise, helo_allow_chars can be used for rogue characters in general
1743 (typically people want to let in underscores).
1746 s the data portion of the line (already past any white space)
1748 Returns: TRUE or FALSE
1752 check_helo(uschar *s)
1755 uschar *end = s + Ustrlen(s);
1756 BOOL yield = helo_accept_junk;
1758 /* Discard any previous helo name */
1760 if (sender_helo_name != NULL)
1762 store_free(sender_helo_name);
1763 sender_helo_name = NULL;
1766 /* Skip tests if junk is permitted. */
1770 /* Allow the new standard form for IPv6 address literals, namely,
1771 [IPv6:....], and because someone is bound to use it, allow an equivalent
1772 IPv4 form. Allow plain addresses as well. */
1779 if (strncmpic(s, US"[IPv6:", 6) == 0)
1780 yield = (string_is_ip_address(s+6, NULL) == 6);
1781 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1782 yield = (string_is_ip_address(s+6, NULL) == 4);
1784 yield = (string_is_ip_address(s+1, NULL) != 0);
1789 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1790 that have been configured (usually underscore - sigh). */
1797 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1798 Ustrchr(helo_allow_chars, *s) == NULL)
1808 /* Save argument if OK */
1810 if (yield) sender_helo_name = string_copy_malloc(start);
1818 /*************************************************
1819 * Extract SMTP command option *
1820 *************************************************/
1822 /* This function picks the next option setting off the end of smtp_cmd_data. It
1823 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1824 things that can appear there.
1827 name point this at the name
1828 value point this at the data string
1830 Returns: TRUE if found an option
1834 extract_option(uschar **name, uschar **value)
1837 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1838 while (isspace(*v)) v--;
1840 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1842 /* Take care to not stop at a space embedded in a quoted local-part */
1844 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1851 while(isalpha(n[-1])) n--;
1852 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1853 if (!isspace(n[-1])) return FALSE;
1859 if (v == smtp_cmd_data) return FALSE;
1871 /*************************************************
1872 * Reset for new message *
1873 *************************************************/
1875 /* This function is called whenever the SMTP session is reset from
1876 within either of the setup functions.
1878 Argument: the stacking pool storage reset point
1883 smtp_reset(void *reset_point)
1885 recipients_list = NULL;
1886 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1887 raw_recipients_count = recipients_count = recipients_list_max = 0;
1888 cancel_cutthrough_connection("smtp reset");
1889 message_linecount = 0;
1891 acl_added_headers = NULL;
1892 acl_removed_headers = NULL;
1893 queue_only_policy = FALSE;
1894 rcpt_smtp_response = NULL;
1895 rcpt_smtp_response_same = TRUE;
1896 rcpt_in_progress = FALSE;
1897 deliver_freeze = FALSE; /* Can be set by ACL */
1898 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1899 fake_response = OK; /* Can be set by ACL */
1900 #ifdef WITH_CONTENT_SCAN
1901 no_mbox_unspool = FALSE; /* Can be set by ACL */
1903 submission_mode = FALSE; /* Can be set by ACL */
1904 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1905 active_local_from_check = local_from_check; /* Can be set by ACL */
1906 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1907 sending_ip_address = NULL;
1908 return_path = sender_address = NULL;
1909 sender_data = NULL; /* Can be set by ACL */
1910 deliver_localpart_orig = NULL;
1911 deliver_domain_orig = NULL;
1912 callout_address = NULL;
1913 submission_name = NULL; /* Can be set by ACL */
1914 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1915 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1916 sender_verified_list = NULL; /* No senders verified */
1917 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1918 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1920 authenticated_sender = NULL;
1921 #ifdef EXPERIMENTAL_BRIGHTMAIL
1923 bmi_verdicts = NULL;
1925 dnslist_domain = dnslist_matched = NULL;
1926 #ifndef DISABLE_DKIM
1927 dkim_signers = NULL;
1928 dkim_disable_verify = FALSE;
1929 dkim_collect_input = FALSE;
1933 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1934 #ifndef DISABLE_PRDR
1935 prdr_requested = FALSE;
1937 #ifdef EXPERIMENTAL_SPF
1938 spf_header_comment = NULL;
1939 spf_received = NULL;
1941 spf_smtp_comment = NULL;
1944 message_smtputf8 = FALSE;
1946 body_linecount = body_zerocount = 0;
1948 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1949 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1950 /* Note that ratelimiters_conn persists across resets. */
1952 /* Reset message ACL variables */
1956 /* The message body variables use malloc store. They may be set if this is
1957 not the first message in an SMTP session and the previous message caused them
1958 to be referenced in an ACL. */
1962 store_free(message_body);
1963 message_body = NULL;
1966 if (message_body_end)
1968 store_free(message_body_end);
1969 message_body_end = NULL;
1972 /* Warning log messages are also saved in malloc store. They are saved to avoid
1973 repetition in the same message, but it seems right to repeat them for different
1976 while (acl_warn_logged)
1978 string_item *this = acl_warn_logged;
1979 acl_warn_logged = acl_warn_logged->next;
1982 store_reset(reset_point);
1989 /*************************************************
1990 * Initialize for incoming batched SMTP message *
1991 *************************************************/
1993 /* This function is called from smtp_setup_msg() in the case when
1994 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1995 of messages in one file with SMTP commands between them. All errors must be
1996 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1997 relevant. After an error on a sender, or an invalid recipient, the remainder
1998 of the message is skipped. The value of received_protocol is already set.
2001 Returns: > 0 message successfully started (reached DATA)
2002 = 0 QUIT read or end of file reached
2003 < 0 should not occur
2007 smtp_setup_batch_msg(void)
2010 void *reset_point = store_get(0);
2012 /* Save the line count at the start of each transaction - single commands
2013 like HELO and RSET count as whole transactions. */
2015 bsmtp_transaction_linecount = receive_linecount;
2017 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2019 smtp_reset(reset_point); /* Reset for start of message */
2021 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2022 value. The values are 2 larger than the required yield of the function. */
2027 uschar *recipient = NULL;
2028 int start, end, sender_domain, recipient_domain;
2030 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2032 /* The HELO/EHLO commands set sender_address_helo if they have
2033 valid data; otherwise they are ignored, except that they do
2034 a reset of the state. */
2039 check_helo(smtp_cmd_data);
2043 smtp_reset(reset_point);
2044 bsmtp_transaction_linecount = receive_linecount;
2048 /* The MAIL FROM command requires an address as an operand. All we
2049 do here is to parse it for syntactic correctness. The form "<>" is
2050 a special case which converts into an empty string. The start/end
2051 pointers in the original are not used further for this address, as
2052 it is the canonical extracted address which is all that is kept. */
2055 smtp_mailcmd_count++; /* Count for no-mail log */
2056 if (sender_address != NULL)
2057 /* The function moan_smtp_batch() does not return. */
2058 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2060 if (smtp_cmd_data[0] == 0)
2061 /* The function moan_smtp_batch() does not return. */
2062 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2064 /* Reset to start of message */
2066 smtp_reset(reset_point);
2068 /* Apply SMTP rewrite */
2070 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2071 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2072 US"", global_rewrite_rules) : smtp_cmd_data;
2074 /* Extract the address; the TRUE flag allows <> as valid */
2077 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2080 if (raw_sender == NULL)
2081 /* The function moan_smtp_batch() does not return. */
2082 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2084 sender_address = string_copy(raw_sender);
2086 /* Qualify unqualified sender addresses if permitted to do so. */
2088 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2090 if (allow_unqualified_sender)
2092 sender_address = rewrite_address_qualify(sender_address, FALSE);
2093 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2094 "and rewritten\n", raw_sender);
2096 /* The function moan_smtp_batch() does not return. */
2097 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2103 /* The RCPT TO command requires an address as an operand. All we do
2104 here is to parse it for syntactic correctness. There may be any number
2105 of RCPT TO commands, specifying multiple senders. We build them all into
2106 a data structure that is in argc/argv format. The start/end values
2107 given by parse_extract_address are not used, as we keep only the
2108 extracted address. */
2111 if (sender_address == NULL)
2112 /* The function moan_smtp_batch() does not return. */
2113 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2115 if (smtp_cmd_data[0] == 0)
2116 /* The function moan_smtp_batch() does not return. */
2117 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2119 /* Check maximum number allowed */
2121 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2122 /* The function moan_smtp_batch() does not return. */
2123 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2124 recipients_max_reject? "552": "452");
2126 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2127 recipient address */
2129 recipient = rewrite_existflags & rewrite_smtp
2130 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2131 global_rewrite_rules)
2134 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2135 &recipient_domain, FALSE);
2138 /* The function moan_smtp_batch() does not return. */
2139 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2141 /* If the recipient address is unqualified, qualify it if permitted. Then
2142 add it to the list of recipients. */
2144 if (recipient_domain == 0)
2146 if (allow_unqualified_recipient)
2148 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2150 recipient = rewrite_address_qualify(recipient, TRUE);
2152 /* The function moan_smtp_batch() does not return. */
2153 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2156 receive_add_recipient(recipient, -1);
2160 /* The DATA command is legal only if it follows successful MAIL FROM
2161 and RCPT TO commands. This function is complete when a valid DATA
2162 command is encountered. */
2165 if (sender_address == NULL || recipients_count <= 0)
2167 /* The function moan_smtp_batch() does not return. */
2168 if (sender_address == NULL)
2169 moan_smtp_batch(smtp_cmd_buffer,
2170 "503 MAIL FROM:<sender> command must precede DATA");
2172 moan_smtp_batch(smtp_cmd_buffer,
2173 "503 RCPT TO:<recipient> must precede DATA");
2177 done = 3; /* DATA successfully achieved */
2178 message_ended = END_NOTENDED; /* Indicate in middle of message */
2183 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2190 bsmtp_transaction_linecount = receive_linecount;
2201 /* The function moan_smtp_batch() does not return. */
2202 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2207 /* The function moan_smtp_batch() does not return. */
2208 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2213 /* The function moan_smtp_batch() does not return. */
2214 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2219 return done - 2; /* Convert yield values */
2226 smtp_log_tls_fail(uschar * errstr)
2228 uschar * conn_info = smtp_get_connection_info();
2230 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2231 /* I'd like to get separated H= here, but too hard for now */
2233 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2238 /*************************************************
2239 * Start an SMTP session *
2240 *************************************************/
2242 /* This function is called at the start of an SMTP session. Thereafter,
2243 smtp_setup_msg() is called to initiate each separate message. This
2244 function does host-specific testing, and outputs the banner line.
2247 Returns: FALSE if the session can not continue; something has
2248 gone wrong, or the connection to the host is blocked
2252 smtp_start_session(void)
2256 uschar *user_msg, *log_msg;
2260 smtp_connection_start = time(NULL);
2261 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2262 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2265 /* Default values for certain variables */
2267 helo_seen = esmtp = helo_accept_junk = FALSE;
2268 smtp_mailcmd_count = 0;
2269 count_nonmail = TRUE_UNSET;
2270 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2271 smtp_delay_mail = smtp_rlm_base;
2272 auth_advertised = FALSE;
2273 pipelining_advertised = FALSE;
2274 pipelining_enable = TRUE;
2275 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2276 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2278 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2279 authentication settings from -oMaa to remain in force. */
2281 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2282 authenticated_by = NULL;
2285 tls_in.cipher = tls_in.peerdn = NULL;
2286 tls_in.ourcert = tls_in.peercert = NULL;
2288 tls_in.ocsp = OCSP_NOT_REQ;
2289 tls_advertised = FALSE;
2291 dsn_advertised = FALSE;
2293 smtputf8_advertised = FALSE;
2296 /* Reset ACL connection variables */
2300 /* Allow for trailing 0 in the command and data buffers. */
2302 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2303 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2304 "malloc() failed for SMTP command buffer");
2306 smtp_cmd_buffer[0] = 0;
2307 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2309 /* For batched input, the protocol setting can be overridden from the
2310 command line by a trusted caller. */
2312 if (smtp_batched_input)
2314 if (!received_protocol) received_protocol = US"local-bsmtp";
2317 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2318 reset later if any of EHLO/AUTH/STARTTLS are received. */
2322 (sender_host_address ? protocols : protocols_local) [pnormal];
2324 /* Set up the buffer for inputting using direct read() calls, and arrange to
2325 call the local functions instead of the standard C ones. */
2327 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2328 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2330 receive_getc = smtp_getc;
2331 receive_get_cache = smtp_get_cache;
2332 receive_ungetc = smtp_ungetc;
2333 receive_feof = smtp_feof;
2334 receive_ferror = smtp_ferror;
2335 receive_smtp_buffered = smtp_buffered;
2336 smtp_inptr = smtp_inend = smtp_inbuffer;
2337 smtp_had_eof = smtp_had_error = 0;
2339 /* Set up the message size limit; this may be host-specific */
2341 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2342 if (expand_string_message != NULL)
2344 if (thismessage_size_limit == -1)
2345 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2346 "%s", expand_string_message);
2348 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2349 "%s", expand_string_message);
2350 smtp_closedown(US"Temporary local problem - please try later");
2354 /* When a message is input locally via the -bs or -bS options, sender_host_
2355 unknown is set unless -oMa was used to force an IP address, in which case it
2356 is checked like a real remote connection. When -bs is used from inetd, this
2357 flag is not set, causing the sending host to be checked. The code that deals
2358 with IP source routing (if configured) is never required for -bs or -bS and
2359 the flag sender_host_notsocket is used to suppress it.
2361 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2362 reserve for certain hosts and/or networks. */
2364 if (!sender_host_unknown)
2367 BOOL reserved_host = FALSE;
2369 /* Look up IP options (source routing info) on the socket if this is not an
2370 -oMa "host", and if any are found, log them and drop the connection.
2372 Linux (and others now, see below) is different to everyone else, so there
2373 has to be some conditional compilation here. Versions of Linux before 2.1.15
2374 used a structure whose name was "options". Somebody finally realized that
2375 this name was silly, and it got changed to "ip_options". I use the
2376 newer name here, but there is a fudge in the script that sets up os.h
2377 to define a macro in older Linux systems.
2379 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2380 glibc 2, which has chosen ip_opts for the structure name. This is now
2381 really a glibc thing rather than a Linux thing, so the condition name
2382 has been changed to reflect this. It is relevant also to GNU/Hurd.
2384 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2385 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2386 a special macro defined in the os.h file.
2388 Some DGUX versions on older hardware appear not to support IP options at
2389 all, so there is now a general macro which can be set to cut out this
2392 How to do this properly in IPv6 is not yet known. */
2394 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2396 #ifdef GLIBC_IP_OPTIONS
2397 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2402 #elif defined DARWIN_IP_OPTIONS
2408 if (!host_checking && !sender_host_notsocket)
2411 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2412 struct ip_options *ipopt = store_get(optlen);
2414 struct ip_opts ipoptblock;
2415 struct ip_opts *ipopt = &ipoptblock;
2416 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2418 struct ipoption ipoptblock;
2419 struct ipoption *ipopt = &ipoptblock;
2420 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2423 /* Occasional genuine failures of getsockopt() have been seen - for
2424 example, "reset by peer". Therefore, just log and give up on this
2425 call, unless the error is ENOPROTOOPT. This error is given by systems
2426 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2427 of writing. So for that error, carry on - we just can't do an IP options
2430 DEBUG(D_receive) debug_printf("checking for IP options\n");
2432 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2435 if (errno != ENOPROTOOPT)
2437 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2438 host_and_ident(FALSE), strerror(errno));
2439 smtp_printf("451 SMTP service not available\r\n");
2444 /* Deal with any IP options that are set. On the systems I have looked at,
2445 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2446 more logging data than will fit in big_buffer. Nevertheless, after somebody
2447 questioned this code, I've added in some paranoid checking. */
2449 else if (optlen > 0)
2451 uschar *p = big_buffer;
2452 uschar *pend = big_buffer + big_buffer_size;
2453 uschar *opt, *adptr;
2455 struct in_addr addr;
2458 uschar *optstart = (uschar *)(ipopt->__data);
2460 uschar *optstart = (uschar *)(ipopt->ip_opts);
2462 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2465 DEBUG(D_receive) debug_printf("IP options exist\n");
2467 Ustrcpy(p, "IP options on incoming call:");
2470 for (opt = optstart; opt != NULL &&
2471 opt < (uschar *)(ipopt) + optlen;)
2485 if (!string_format(p, pend-p, " %s [@%s",
2486 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2488 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2490 inet_ntoa(ipopt->ip_dst)))
2492 inet_ntoa(ipopt->ipopt_dst)))
2500 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2502 while (optcount-- > 0)
2504 memcpy(&addr, adptr, sizeof(addr));
2505 if (!string_format(p, pend - p - 1, "%s%s",
2506 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2512 adptr += sizeof(struct in_addr);
2521 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2524 for (i = 0; i < opt[1]; i++)
2526 sprintf(CS p, "%2.2x ", opt[i]);
2537 log_write(0, LOG_MAIN, "%s", big_buffer);
2539 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2541 log_write(0, LOG_MAIN|LOG_REJECT,
2542 "connection from %s refused (IP options)", host_and_ident(FALSE));
2544 smtp_printf("554 SMTP service not available\r\n");
2548 /* Length of options = 0 => there are no options */
2550 else DEBUG(D_receive) debug_printf("no IP options found\n");
2552 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2554 /* Set keep-alive in socket options. The option is on by default. This
2555 setting is an attempt to get rid of some hanging connections that stick in
2556 read() when the remote end (usually a dialup) goes away. */
2558 if (smtp_accept_keepalive && !sender_host_notsocket)
2559 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2561 /* If the current host matches host_lookup, set the name by doing a
2562 reverse lookup. On failure, sender_host_name will be NULL and
2563 host_lookup_failed will be TRUE. This may or may not be serious - optional
2566 if (verify_check_host(&host_lookup) == OK)
2568 (void)host_name_lookup();
2569 host_build_sender_fullhost();
2572 /* Delay this until we have the full name, if it is looked up. */
2574 set_process_info("handling incoming connection from %s",
2575 host_and_ident(FALSE));
2577 /* Expand smtp_receive_timeout, if needed */
2579 if (smtp_receive_timeout_s)
2582 if ( !(exp = expand_string(smtp_receive_timeout_s))
2584 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2586 log_write(0, LOG_MAIN|LOG_PANIC,
2587 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2590 /* Test for explicit connection rejection */
2592 if (verify_check_host(&host_reject_connection) == OK)
2594 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2595 "from %s (host_reject_connection)", host_and_ident(FALSE));
2596 smtp_printf("554 SMTP service not available\r\n");
2600 /* Test with TCP Wrappers if so configured. There is a problem in that
2601 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2602 such as disks dying. In these cases, it is desirable to reject with a 4xx
2603 error instead of a 5xx error. There isn't a "right" way to detect such
2604 problems. The following kludge is used: errno is zeroed before calling
2605 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2606 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2609 #ifdef USE_TCP_WRAPPERS
2611 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2612 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2613 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2614 expand_string_message);
2616 if (!hosts_ctl(tcp_wrappers_name,
2617 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2618 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2619 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2621 if (errno == 0 || errno == ENOENT)
2623 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2624 log_write(L_connection_reject,
2625 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2626 "(tcp wrappers)", host_and_ident(FALSE));
2627 smtp_printf("554 SMTP service not available\r\n");
2631 int save_errno = errno;
2632 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2633 "errno value %d\n", save_errno);
2634 log_write(L_connection_reject,
2635 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2636 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2637 smtp_printf("451 Temporary local problem - please try later\r\n");
2643 /* Check for reserved slots. The value of smtp_accept_count has already been
2644 incremented to include this process. */
2646 if (smtp_accept_max > 0 &&
2647 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2649 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2651 log_write(L_connection_reject,
2652 LOG_MAIN, "temporarily refused connection from %s: not in "
2653 "reserve list: connected=%d max=%d reserve=%d%s",
2654 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2655 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2656 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2657 "please try again later\r\n", smtp_active_hostname);
2660 reserved_host = TRUE;
2663 /* If a load level above which only messages from reserved hosts are
2664 accepted is set, check the load. For incoming calls via the daemon, the
2665 check is done in the superior process if there are no reserved hosts, to
2666 save a fork. In all cases, the load average will already be available
2667 in a global variable at this point. */
2669 if (smtp_load_reserve >= 0 &&
2670 load_average > smtp_load_reserve &&
2672 verify_check_host(&smtp_reserve_hosts) != OK)
2674 log_write(L_connection_reject,
2675 LOG_MAIN, "temporarily refused connection from %s: not in "
2676 "reserve list and load average = %.2f", host_and_ident(FALSE),
2677 (double)load_average/1000.0);
2678 smtp_printf("421 %s: Too much load; please try again later\r\n",
2679 smtp_active_hostname);
2683 /* Determine whether unqualified senders or recipients are permitted
2684 for this host. Unfortunately, we have to do this every time, in order to
2685 set the flags so that they can be inspected when considering qualifying
2686 addresses in the headers. For a site that permits no qualification, this
2687 won't take long, however. */
2689 allow_unqualified_sender =
2690 verify_check_host(&sender_unqualified_hosts) == OK;
2692 allow_unqualified_recipient =
2693 verify_check_host(&recipient_unqualified_hosts) == OK;
2695 /* Determine whether HELO/EHLO is required for this host. The requirement
2696 can be hard or soft. */
2698 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2700 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2702 /* Determine whether this hosts is permitted to send syntactic junk
2703 after a HELO or EHLO command. */
2705 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2708 /* For batch SMTP input we are now done. */
2710 if (smtp_batched_input) return TRUE;
2712 /* If valid Proxy Protocol source is connecting, set up session.
2713 * Failure will not allow any SMTP function other than QUIT. */
2715 #ifdef SUPPORT_PROXY
2716 proxy_session = FALSE;
2717 proxy_session_failed = FALSE;
2718 if (check_proxy_protocol_host())
2719 setup_proxy_protocol_host();
2722 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2723 smtps port for use with older style SSL MTAs. */
2726 if (tls_in.on_connect && tls_server_start(tls_require_ciphers, &user_msg) != OK)
2727 return smtp_log_tls_fail(user_msg);
2730 /* Run the connect ACL if it exists */
2733 if (acl_smtp_connect)
2736 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2739 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2744 /* Output the initial message for a two-way SMTP connection. It may contain
2745 newlines, which then cause a multi-line response to be given. */
2747 code = US"220"; /* Default status code */
2748 esc = US""; /* Default extended status code */
2749 esclen = 0; /* Length of esc */
2753 if (!(s = expand_string(smtp_banner)))
2754 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2755 "failed: %s", smtp_banner, expand_string_message);
2761 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2765 esclen = codelen - 4;
2769 /* Remove any terminating newlines; might as well remove trailing space too */
2772 while (p > s && isspace(p[-1])) p--;
2775 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2776 is all contained in a single IP packet. The original code wrote out the
2777 greeting using several calls to fprint/fputc, and on busy servers this could
2778 cause it to be split over more than one packet - which caused CC:Mail to fall
2779 over when it got the second part of the greeting after sending its first
2780 command. Sigh. To try to avoid this, build the complete greeting message
2781 first, and output it in one fell swoop. This gives a better chance of it
2782 ending up as a single packet. */
2784 ss = store_get(size);
2788 do /* At least once, in case we have an empty string */
2791 uschar *linebreak = Ustrchr(p, '\n');
2792 ss = string_catn(ss, &size, &ptr, code, 3);
2793 if (linebreak == NULL)
2796 ss = string_catn(ss, &size, &ptr, US" ", 1);
2800 len = linebreak - p;
2801 ss = string_catn(ss, &size, &ptr, US"-", 1);
2803 ss = string_catn(ss, &size, &ptr, esc, esclen);
2804 ss = string_catn(ss, &size, &ptr, p, len);
2805 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2807 if (linebreak != NULL) p++;
2811 ss[ptr] = 0; /* string_cat leaves room for this */
2813 /* Before we write the banner, check that there is no input pending, unless
2814 this synchronisation check is disabled. */
2818 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2819 "synchronization error (input sent without waiting for greeting): "
2820 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2821 string_printing(smtp_inptr));
2822 smtp_printf("554 SMTP synchronization error\r\n");
2826 /* Now output the banner */
2828 smtp_printf("%s", ss);
2836 /*************************************************
2837 * Handle SMTP syntax and protocol errors *
2838 *************************************************/
2840 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2841 to do so. Then transmit the error response. The return value depends on the
2842 number of syntax and protocol errors in this SMTP session.
2845 type error type, given as a log flag bit
2846 code response code; <= 0 means don't send a response
2847 data data to reflect in the response (can be NULL)
2848 errmess the error message
2850 Returns: -1 limit of syntax/protocol errors NOT exceeded
2851 +1 limit of syntax/protocol errors IS exceeded
2853 These values fit in with the values of the "done" variable in the main
2854 processing loop in smtp_setup_msg(). */
2857 synprot_error(int type, int code, uschar *data, uschar *errmess)
2861 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2862 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2863 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2865 if (++synprot_error_count > smtp_max_synprot_errors)
2868 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2869 "syntax or protocol errors (last command was \"%s\")",
2870 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2875 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2876 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2878 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2887 /*************************************************
2888 * Send SMTP response, possibly multiline *
2889 *************************************************/
2891 /* There are, it seems, broken clients out there that cannot handle multiline
2892 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2893 output nothing for non-final calls, and only the first line for anything else.
2896 code SMTP code, may involve extended status codes
2897 codelen length of smtp code; if > 4 there's an ESC
2898 final FALSE if the last line isn't the final line
2899 msg message text, possibly containing newlines
2905 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2910 if (!final && no_multiline_responses) return;
2915 esclen = codelen - 4;
2918 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2919 have had the same. Note: this code is also present in smtp_printf(). It would
2920 be tidier to have it only in one place, but when it was added, it was easier to
2921 do it that way, so as not to have to mess with the code for the RCPT command,
2922 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2924 if (rcpt_in_progress)
2926 if (rcpt_smtp_response == NULL)
2927 rcpt_smtp_response = string_copy(msg);
2928 else if (rcpt_smtp_response_same &&
2929 Ustrcmp(rcpt_smtp_response, msg) != 0)
2930 rcpt_smtp_response_same = FALSE;
2931 rcpt_in_progress = FALSE;
2934 /* Not output the message, splitting it up into multiple lines if necessary. */
2938 uschar *nl = Ustrchr(msg, '\n');
2941 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2944 else if (nl[1] == 0 || no_multiline_responses)
2946 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2947 (int)(nl - msg), msg);
2952 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2954 while (isspace(*msg)) msg++;
2962 /*************************************************
2963 * Parse user SMTP message *
2964 *************************************************/
2966 /* This function allows for user messages overriding the response code details
2967 by providing a suitable response code string at the start of the message
2968 user_msg. Check the message for starting with a response code and optionally an
2969 extended status code. If found, check that the first digit is valid, and if so,
2970 change the code pointer and length to use the replacement. An invalid code
2971 causes a panic log; in this case, if the log messages is the same as the user
2972 message, we must also adjust the value of the log message to show the code that
2973 is actually going to be used (the original one).
2975 This function is global because it is called from receive.c as well as within
2978 Note that the code length returned includes the terminating whitespace
2979 character, which is always included in the regex match.
2982 code SMTP code, may involve extended status codes
2983 codelen length of smtp code; if > 4 there's an ESC
2985 log_msg optional log message, to be adjusted with the new SMTP code
2986 check_valid if true, verify the response code
2992 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2998 if (!msg || !*msg) return;
3000 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3001 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3003 if (check_valid && (*msg)[0] != (*code)[0])
3005 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3006 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3007 if (log_msg != NULL && *log_msg == *msg)
3008 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3013 *codelen = ovector[1]; /* Includes final space */
3015 *msg += ovector[1]; /* Chop the code off the message */
3022 /*************************************************
3023 * Handle an ACL failure *
3024 *************************************************/
3026 /* This function is called when acl_check() fails. As well as calls from within
3027 this module, it is called from receive.c for an ACL after DATA. It sorts out
3028 logging the incident, and sets up the error response. A message containing
3029 newlines is turned into a multiline SMTP response, but for logging, only the
3032 There's a table of default permanent failure response codes to use in
3033 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3034 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3035 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3036 state, because there are broken clients that try VRFY before RCPT. A 5xx
3037 response should be given only when the address is positively known to be
3038 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3039 no explicit code, but if there is one we let it know best.
3040 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3042 From Exim 4.63, it is possible to override the response code details by
3043 providing a suitable response code string at the start of the message provided
3044 in user_msg. The code's first digit is checked for validity.
3047 where where the ACL was called from
3049 user_msg a message that can be included in an SMTP response
3050 log_msg a message for logging
3052 Returns: 0 in most cases
3053 2 if the failure code was FAIL_DROP, in which case the
3054 SMTP connection should be dropped (this value fits with the
3055 "done" variable in smtp_setup_msg() below)
3059 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3061 BOOL drop = rc == FAIL_DROP;
3065 uschar *sender_info = US"";
3067 #ifdef WITH_CONTENT_SCAN
3068 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3070 where == ACL_WHERE_PREDATA ? US"DATA" :
3071 where == ACL_WHERE_DATA ? US"after DATA" :
3072 #ifndef DISABLE_PRDR
3073 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3076 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3077 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3079 if (drop) rc = FAIL;
3081 /* Set the default SMTP code, and allow a user message to change it. */
3083 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3084 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3085 where != ACL_WHERE_VRFY);
3087 /* We used to have sender_address here; however, there was a bug that was not
3088 updating sender_address after a rewrite during a verify. When this bug was
3089 fixed, sender_address at this point became the rewritten address. I'm not sure
3090 this is what should be logged, so I've changed to logging the unrewritten
3091 address to retain backward compatibility. */
3093 #ifndef WITH_CONTENT_SCAN
3094 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3096 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3099 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3100 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3101 sender_host_authenticated ? US" A=" : US"",
3102 sender_host_authenticated ? sender_host_authenticated : US"",
3103 sender_host_authenticated && authenticated_id ? US":" : US"",
3104 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3108 /* If there's been a sender verification failure with a specific message, and
3109 we have not sent a response about it yet, do so now, as a preliminary line for
3110 failures, but not defers. However, always log it for defer, and log it for fail
3111 unless the sender_verify_fail log selector has been turned off. */
3113 if (sender_verified_failed &&
3114 !testflag(sender_verified_failed, af_sverify_told))
3116 BOOL save_rcpt_in_progress = rcpt_in_progress;
3117 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3119 setflag(sender_verified_failed, af_sverify_told);
3121 if (rc != FAIL || LOGGING(sender_verify_fail))
3122 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3123 host_and_ident(TRUE),
3124 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3125 sender_verified_failed->address,
3126 (sender_verified_failed->message == NULL)? US"" :
3127 string_sprintf(": %s", sender_verified_failed->message));
3129 if (rc == FAIL && sender_verified_failed->user_message)
3130 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3131 testflag(sender_verified_failed, af_verify_pmfail)?
3132 "Postmaster verification failed while checking <%s>\n%s\n"
3133 "Several RFCs state that you are required to have a postmaster\n"
3134 "mailbox for each mail domain. This host does not accept mail\n"
3135 "from domains whose servers reject the postmaster address."
3137 testflag(sender_verified_failed, af_verify_nsfail)?
3138 "Callback setup failed while verifying <%s>\n%s\n"
3139 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3140 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3141 "RFC requirements, and stops you from receiving standard bounce\n"
3142 "messages. This host does not accept mail from domains whose servers\n"
3145 "Verification failed for <%s>\n%s",
3146 sender_verified_failed->address,
3147 sender_verified_failed->user_message));
3149 rcpt_in_progress = save_rcpt_in_progress;
3152 /* Sort out text for logging */
3154 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3155 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3157 /* Send permanent failure response to the command, but the code used isn't
3158 always a 5xx one - see comments at the start of this function. If the original
3159 rc was FAIL_DROP we drop the connection and yield 2. */
3162 smtp_respond(smtp_code, codelen, TRUE,
3163 user_msg ? user_msg : US"Administrative prohibition");
3165 /* Send temporary failure response to the command. Don't give any details,
3166 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3167 verb, and for a header verify when smtp_return_error_details is set.
3169 This conditional logic is all somewhat of a mess because of the odd
3170 interactions between temp_details and return_error_details. One day it should
3171 be re-implemented in a tidier fashion. */
3174 if (acl_temp_details && user_msg)
3176 if ( smtp_return_error_details
3177 && sender_verified_failed
3178 && sender_verified_failed->message
3180 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3182 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3185 smtp_respond(smtp_code, codelen, TRUE,
3186 US"Temporary local problem - please try later");
3188 /* Log the incident to the logs that are specified by log_reject_target
3189 (default main, reject). This can be empty to suppress logging of rejections. If
3190 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3191 is closing if required and return 2. */
3193 if (log_reject_target != 0)
3196 uschar * tls = s_tlslog(NULL, NULL, NULL);
3197 if (!tls) tls = US"";
3199 uschar * tls = US"";
3201 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3202 log_reject_target, "%s%s%s %s%srejected %s%s",
3203 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3204 host_and_ident(TRUE),
3207 rc == FAIL ? US"" : US"temporarily ",
3211 if (!drop) return 0;
3213 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3214 smtp_get_connection_info());
3216 /* Run the not-quit ACL, but without any custom messages. This should not be a
3217 problem, because we get here only if some other ACL has issued "drop", and
3218 in that case, *its* custom messages will have been used above. */
3220 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3227 /*************************************************
3228 * Handle SMTP exit when QUIT is not given *
3229 *************************************************/
3231 /* This function provides a logging/statistics hook for when an SMTP connection
3232 is dropped on the floor or the other end goes away. It's a global function
3233 because it's called from receive.c as well as this module. As well as running
3234 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3235 response, either with a custom message from the ACL, or using a default. There
3236 is one case, however, when no message is output - after "drop". In that case,
3237 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3238 passed to this function.
3240 In case things go wrong while processing this function, causing an error that
3241 may re-enter this function, there is a recursion check.
3244 reason What $smtp_notquit_reason will be set to in the ACL;
3245 if NULL, the ACL is not run
3246 code The error code to return as part of the response
3247 defaultrespond The default message if there's no user_msg
3253 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3256 uschar *user_msg = NULL;
3257 uschar *log_msg = NULL;
3259 /* Check for recursive acll */
3261 if (smtp_exit_function_called)
3263 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3267 smtp_exit_function_called = TRUE;
3269 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3271 if (acl_smtp_notquit && reason)
3273 smtp_notquit_reason = reason;
3274 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3275 &log_msg)) == ERROR)
3276 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3280 /* Write an SMTP response if we are expected to give one. As the default
3281 responses are all internal, they should always fit in the buffer, but code a
3282 warning, just in case. Note that string_vformat() still leaves a complete
3283 string, even if it is incomplete. */
3285 if (code && defaultrespond)
3288 smtp_respond(code, 3, TRUE, user_msg);
3293 va_start(ap, defaultrespond);
3294 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3295 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3296 smtp_printf("%s %s\r\n", code, buffer);
3306 /*************************************************
3307 * Verify HELO argument *
3308 *************************************************/
3310 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3311 matched. It is also called from ACL processing if verify = helo is used and
3312 verification was not previously tried (i.e. helo_try_verify_hosts was not
3313 matched). The result of its processing is to set helo_verified and
3314 helo_verify_failed. These variables should both be FALSE for this function to
3317 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3318 for IPv6 ::ffff: literals.
3321 Returns: TRUE if testing was completed;
3322 FALSE on a temporary failure
3326 smtp_verify_helo(void)
3330 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3333 if (sender_helo_name == NULL)
3335 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3338 /* Deal with the case of -bs without an IP address */
3340 else if (sender_host_address == NULL)
3342 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3343 helo_verified = TRUE;
3346 /* Deal with the more common case when there is a sending IP address */
3348 else if (sender_helo_name[0] == '[')
3350 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3351 Ustrlen(sender_host_address)) == 0;
3356 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3357 helo_verified = Ustrncmp(sender_helo_name + 1,
3358 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3363 { if (helo_verified) debug_printf("matched host address\n"); }
3366 /* Do a reverse lookup if one hasn't already given a positive or negative
3367 response. If that fails, or the name doesn't match, try checking with a forward
3372 if (sender_host_name == NULL && !host_lookup_failed)
3373 yield = host_name_lookup() != DEFER;
3375 /* If a host name is known, check it and all its aliases. */
3377 if (sender_host_name)
3378 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3380 sender_helo_dnssec = sender_host_dnssec;
3381 HDEBUG(D_receive) debug_printf("matched host name\n");
3385 uschar **aliases = sender_host_aliases;
3387 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3389 sender_helo_dnssec = sender_host_dnssec;
3393 HDEBUG(D_receive) if (helo_verified)
3394 debug_printf("matched alias %s\n", *(--aliases));
3397 /* Final attempt: try a forward lookup of the helo name */
3406 h.name = sender_helo_name;
3413 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3415 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3416 NULL, NULL, NULL, &d, NULL, NULL);
3417 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3418 for (hh = &h; hh; hh = hh->next)
3419 if (Ustrcmp(hh->address, sender_host_address) == 0)
3421 helo_verified = TRUE;
3422 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3425 debug_printf("IP address for %s matches calling address\n"
3426 "Forward DNS security status: %sverified\n",
3427 sender_helo_name, sender_helo_dnssec ? "" : "un");
3434 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3441 /*************************************************
3442 * Send user response message *
3443 *************************************************/
3445 /* This function is passed a default response code and a user message. It calls
3446 smtp_message_code() to check and possibly modify the response code, and then
3447 calls smtp_respond() to transmit the response. I put this into a function
3448 just to avoid a lot of repetition.
3451 code the response code
3452 user_msg the user message
3458 smtp_user_msg(uschar *code, uschar *user_msg)
3461 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3462 smtp_respond(code, len, TRUE, user_msg);
3468 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3470 const uschar *set_id = NULL;
3473 /* Run the checking code, passing the remainder of the command line as
3474 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3475 it as the only set numerical variable. The authenticator may set $auth<n>
3476 and also set other numeric variables. The $auth<n> variables are preferred
3477 nowadays; the numerical variables remain for backwards compatibility.
3479 Afterwards, have a go at expanding the set_id string, even if
3480 authentication failed - for bad passwords it can be useful to log the
3481 userid. On success, require set_id to expand and exist, and put it in
3482 authenticated_id. Save this in permanent store, as the working store gets
3483 reset at HELO, RSET, etc. */
3485 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3487 expand_nlength[0] = 0; /* $0 contains nothing */
3489 rc = (au->info->servercode)(au, smtp_cmd_data);
3490 if (au->set_id) set_id = expand_string(au->set_id);
3491 expand_nmax = -1; /* Reset numeric variables */
3492 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3494 /* The value of authenticated_id is stored in the spool file and printed in
3495 log lines. It must not contain binary zeros or newline characters. In
3496 normal use, it never will, but when playing around or testing, this error
3497 can (did) happen. To guard against this, ensure that the id contains only
3498 printing characters. */
3500 if (set_id) set_id = string_printing(set_id);
3502 /* For the non-OK cases, set up additional logging data if set_id
3506 set_id = set_id && *set_id
3507 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3509 /* Switch on the result */
3514 if (!au->set_id || set_id) /* Complete success */
3516 if (set_id) authenticated_id = string_copy_malloc(set_id);
3517 sender_host_authenticated = au->name;
3518 authentication_failed = FALSE;
3519 authenticated_fail_id = NULL; /* Impossible to already be set? */
3522 (sender_host_address ? protocols : protocols_local)
3523 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3524 *s = *ss = US"235 Authentication succeeded";
3525 authenticated_by = au;
3529 /* Authentication succeeded, but we failed to expand the set_id string.
3530 Treat this as a temporary error. */
3532 auth_defer_msg = expand_string_message;
3536 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3537 *s = string_sprintf("435 Unable to authenticate at present%s",
3538 auth_defer_user_msg);
3539 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3540 set_id, auth_defer_msg);
3544 *s = *ss = US"501 Invalid base64 data";
3548 *s = *ss = US"501 Authentication cancelled";
3552 *s = *ss = US"553 Initial data not expected";
3556 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3557 *s = US"535 Incorrect authentication data";
3558 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3562 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3563 *s = US"435 Internal error";
3564 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3565 "check", set_id, rc);
3577 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3580 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3582 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3584 rd = Ustrlen(recipient) + 1;
3585 *recipient = rewrite_address_qualify(*recipient, TRUE);
3588 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3590 log_write(L_smtp_syntax_error,
3591 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3592 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3600 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3603 incomplete_transaction_log(US"QUIT");
3606 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3608 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3612 smtp_respond(US"221", 3, TRUE, *user_msgp);
3614 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3617 tls_close(TRUE, TRUE);
3620 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3621 smtp_get_connection_info());
3626 smtp_rset_handler(void)
3629 incomplete_transaction_log(US"RSET");
3630 smtp_printf("250 Reset OK\r\n");
3631 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3636 /*************************************************
3637 * Initialize for SMTP incoming message *
3638 *************************************************/
3640 /* This function conducts the initial dialogue at the start of an incoming SMTP
3641 message, and builds a list of recipients. However, if the incoming message
3642 is part of a batch (-bS option) a separate function is called since it would
3643 be messy having tests splattered about all over this function. This function
3644 therefore handles the case where interaction is occurring. The input and output
3645 files are set up in smtp_in and smtp_out.
3647 The global recipients_list is set to point to a vector of recipient_item
3648 blocks, whose number is given by recipients_count. This is extended by the
3649 receive_add_recipient() function. The global variable sender_address is set to
3650 the sender's address. The yield is +1 if a message has been successfully
3651 started, 0 if a QUIT command was encountered or the connection was refused from
3652 the particular host, or -1 if the connection was lost.
3656 Returns: > 0 message successfully started (reached DATA)
3657 = 0 QUIT read or end of file reached or call refused
3662 smtp_setup_msg(void)
3665 BOOL toomany = FALSE;
3666 BOOL discarded = FALSE;
3667 BOOL last_was_rej_mail = FALSE;
3668 BOOL last_was_rcpt = FALSE;
3669 void *reset_point = store_get(0);
3671 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3673 /* Reset for start of new message. We allow one RSET not to be counted as a
3674 nonmail command, for those MTAs that insist on sending it between every
3675 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3676 TLS between messages (an Exim client may do this if it has messages queued up
3677 for the host). Note: we do NOT reset AUTH at this point. */
3679 smtp_reset(reset_point);
3680 message_ended = END_NOTSTARTED;
3682 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3684 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3685 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3686 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3688 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3689 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3692 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3694 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3696 /* Batched SMTP is handled in a different function. */
3698 if (smtp_batched_input) return smtp_setup_batch_msg();
3700 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3701 value. The values are 2 larger than the required yield of the function. */
3705 const uschar **argv;
3706 uschar *etrn_command;
3707 uschar *etrn_serialize_key;
3709 uschar *log_msg, *smtp_code;
3710 uschar *user_msg = NULL;
3711 uschar *recipient = NULL;
3712 uschar *hello = NULL;
3714 BOOL was_rej_mail = FALSE;
3715 BOOL was_rcpt = FALSE;
3716 void (*oldsignal)(int);
3718 int start, end, sender_domain, recipient_domain;
3722 uschar *orcpt = NULL;
3726 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3727 if ( tls_in.active >= 0
3729 && tls_in.certificate_verified
3730 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3733 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3735 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3736 &user_msg, &log_msg)) != OK
3739 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3743 for (au = auths; au; au = au->next)
3744 if (strcmpic(US"tls", au->driver_name) == 0)
3746 smtp_cmd_data = NULL;
3748 if (smtp_in_auth(au, &s, &ss) == OK)
3749 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3751 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3758 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3759 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3760 US &off, sizeof(off));
3763 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3765 /* The AUTH command is not permitted to occur inside a transaction, and may
3766 occur successfully only once per connection. Actually, that isn't quite
3767 true. When TLS is started, all previous information about a connection must
3768 be discarded, so a new AUTH is permitted at that time.
3770 AUTH may only be used when it has been advertised. However, it seems that
3771 there are clients that send AUTH when it hasn't been advertised, some of
3772 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3773 So there's a get-out that allows this to happen.
3775 AUTH is initially labelled as a "nonmail command" so that one occurrence
3776 doesn't get counted. We change the label here so that multiple failing
3777 AUTHS will eventually hit the nonmail threshold. */
3781 authentication_failed = TRUE;
3782 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3784 if (!auth_advertised && !allow_auth_unadvertised)
3786 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3787 US"AUTH command used when not advertised");
3790 if (sender_host_authenticated)
3792 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3793 US"already authenticated");
3798 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3799 US"not permitted in mail transaction");
3806 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3807 &user_msg, &log_msg)) != OK
3810 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3814 /* Find the name of the requested authentication mechanism. */
3817 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3819 if (!isalnum(c) && c != '-' && c != '_')
3821 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3822 US"invalid character in authentication mechanism name");
3828 /* If not at the end of the line, we must be at white space. Terminate the
3829 name and move the pointer on to any data that may be present. */
3831 if (*smtp_cmd_data != 0)
3833 *smtp_cmd_data++ = 0;
3834 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3837 /* Search for an authentication mechanism which is configured for use
3838 as a server and which has been advertised (unless, sigh, allow_auth_
3839 unadvertised is set). */
3841 for (au = auths; au; au = au->next)
3842 if (strcmpic(s, au->public_name) == 0 && au->server &&
3843 (au->advertised || allow_auth_unadvertised))
3848 c = smtp_in_auth(au, &s, &ss);
3850 smtp_printf("%s\r\n", s);
3852 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3853 au->name, host_and_ident(FALSE), ss);
3856 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3857 string_sprintf("%s authentication mechanism not supported", s));
3859 break; /* AUTH_CMD */
3861 /* The HELO/EHLO commands are permitted to appear in the middle of a
3862 session as well as at the beginning. They have the effect of a reset in
3863 addition to their other functions. Their absence at the start cannot be
3864 taken to be an error.
3868 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3869 or 502 failure replies MUST be returned as appropriate. The SMTP
3870 server MUST stay in the same state after transmitting these replies
3871 that it was in before the EHLO was received.
3873 Therefore, we do not do the reset until after checking the command for
3874 acceptability. This change was made for Exim release 4.11. Previously
3875 it did the reset first. */
3888 HELO_EHLO: /* Common code for HELO and EHLO */
3889 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3890 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3892 /* Reject the HELO if its argument was invalid or non-existent. A
3893 successful check causes the argument to be saved in malloc store. */
3895 if (!check_helo(smtp_cmd_data))
3897 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3899 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3900 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3901 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3902 string_printing(smtp_cmd_argument));
3904 if (++synprot_error_count > smtp_max_synprot_errors)
3906 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3907 "syntax or protocol errors (last command was \"%s\")",
3908 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3915 /* If sender_host_unknown is true, we have got here via the -bs interface,
3916 not called from inetd. Otherwise, we are running an IP connection and the
3917 host address will be set. If the helo name is the primary name of this
3918 host and we haven't done a reverse lookup, force one now. If helo_required
3919 is set, ensure that the HELO name matches the actual host. If helo_verify
3920 is set, do the same check, but softly. */
3922 if (!sender_host_unknown)
3924 BOOL old_helo_verified = helo_verified;
3925 uschar *p = smtp_cmd_data;
3927 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3930 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3931 because otherwise the log can be confusing. */
3933 if (sender_host_name == NULL &&
3934 (deliver_domain = sender_helo_name, /* set $domain */
3935 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3936 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3937 (void)host_name_lookup();
3939 /* Rebuild the fullhost info to include the HELO name (and the real name
3940 if it was looked up.) */
3942 host_build_sender_fullhost(); /* Rebuild */
3943 set_process_info("handling%s incoming connection from %s",
3944 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3946 /* Verify if configured. This doesn't give much security, but it does
3947 make some people happy to be able to do it. If helo_required is set,
3948 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3949 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3950 now obsolescent, since the verification can now be requested selectively
3953 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3954 if (helo_required || helo_verify)
3956 BOOL tempfail = !smtp_verify_helo();
3961 smtp_printf("%d %s argument does not match calling host\r\n",
3962 tempfail? 451 : 550, hello);
3963 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3964 tempfail? "temporarily " : "",
3965 hello, sender_helo_name, host_and_ident(FALSE));
3966 helo_verified = old_helo_verified;
3967 break; /* End of HELO/EHLO processing */
3969 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3970 "helo_try_verify_hosts\n", hello);
3975 #ifdef EXPERIMENTAL_SPF
3976 /* set up SPF context */
3977 spf_init(sender_helo_name, sender_host_address);
3980 /* Apply an ACL check if one is defined; afterwards, recheck
3981 synchronization in case the client started sending in a delay. */
3984 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3985 &user_msg, &log_msg)) != OK)
3987 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3988 sender_helo_name = NULL;
3989 host_build_sender_fullhost(); /* Rebuild */
3992 else if (!check_sync()) goto SYNC_FAILURE;
3994 /* Generate an OK reply. The default string includes the ident if present,
3995 and also the IP address if present. Reflecting back the ident is intended
3996 as a deterrent to mail forgers. For maximum efficiency, and also because
3997 some broken systems expect each response to be in a single packet, arrange
3998 that the entire reply is sent in one write(). */
4000 auth_advertised = FALSE;
4001 pipelining_advertised = FALSE;
4003 tls_advertised = FALSE;
4005 dsn_advertised = FALSE;
4007 smtputf8_advertised = FALSE;
4010 smtp_code = US"250 "; /* Default response code plus space*/
4011 if (user_msg == NULL)
4013 s = string_sprintf("%.3s %s Hello %s%s%s",
4015 smtp_active_hostname,
4016 (sender_ident == NULL)? US"" : sender_ident,
4017 (sender_ident == NULL)? US"" : US" at ",
4018 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
4023 if (sender_host_address != NULL)
4025 s = string_catn(s, &size, &ptr, US" [", 2);
4026 s = string_cat (s, &size, &ptr, sender_host_address);
4027 s = string_catn(s, &size, &ptr, US"]", 1);
4031 /* A user-supplied EHLO greeting may not contain more than one line. Note
4032 that the code returned by smtp_message_code() includes the terminating
4033 whitespace character. */
4039 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4040 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4041 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4043 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4044 "newlines: message truncated: %s", string_printing(s));
4051 s = string_catn(s, &size, &ptr, US"\r\n", 2);
4053 /* If we received EHLO, we must create a multiline response which includes
4054 the functions supported. */
4060 /* I'm not entirely happy with this, as an MTA is supposed to check
4061 that it has enough room to accept a message of maximum size before
4062 it sends this. However, there seems little point in not sending it.
4063 The actual size check happens later at MAIL FROM time. By postponing it
4064 till then, VRFY and EXPN can be used after EHLO when space is short. */
4066 if (thismessage_size_limit > 0)
4068 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4069 thismessage_size_limit);
4070 s = string_cat(s, &size, &ptr, big_buffer);
4074 s = string_catn(s, &size, &ptr, smtp_code, 3);
4075 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
4078 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4079 clean; if it has an 8-bit character in its hand, it just sends it. It
4080 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4081 However, some users want this option simply in order to stop MUAs
4082 mangling messages that contain top-bit-set characters. It is therefore
4083 provided as an option. */
4085 if (accept_8bitmime)
4087 s = string_catn(s, &size, &ptr, smtp_code, 3);
4088 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
4091 /* Advertise DSN support if configured to do so. */
4092 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4094 s = string_catn(s, &size, &ptr, smtp_code, 3);
4095 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
4096 dsn_advertised = TRUE;
4099 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4100 permitted to issue them; a check is made when any host actually tries. */
4104 s = string_catn(s, &size, &ptr, smtp_code, 3);
4105 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
4109 s = string_catn(s, &size, &ptr, smtp_code, 3);
4110 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
4114 s = string_catn(s, &size, &ptr, smtp_code, 3);
4115 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
4118 /* Exim is quite happy with pipelining, so let the other end know that
4119 it is safe to use it, unless advertising is disabled. */
4121 if (pipelining_enable &&
4122 verify_check_host(&pipelining_advertise_hosts) == OK)
4124 s = string_catn(s, &size, &ptr, smtp_code, 3);
4125 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
4126 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4127 pipelining_advertised = TRUE;
4131 /* If any server authentication mechanisms are configured, advertise
4132 them if the current host is in auth_advertise_hosts. The problem with
4133 advertising always is that some clients then require users to
4134 authenticate (and aren't configurable otherwise) even though it may not
4135 be necessary (e.g. if the host is in host_accept_relay).
4137 RFC 2222 states that SASL mechanism names contain only upper case
4138 letters, so output the names in upper case, though we actually recognize
4139 them in either case in the AUTH command. */
4143 && !sender_host_authenticated
4145 && verify_check_host(&auth_advertise_hosts) == OK
4150 for (au = auths; au; au = au->next)
4151 if (au->server && (au->advertise_condition == NULL ||
4152 expand_check_condition(au->advertise_condition, au->name,
4153 US"authenticator")))
4158 s = string_catn(s, &size, &ptr, smtp_code, 3);
4159 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
4161 auth_advertised = TRUE;
4164 s = string_catn(s, &size, &ptr, US" ", 1);
4165 s = string_cat (s, &size, &ptr, au->public_name);
4166 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
4167 au->advertised = TRUE;
4170 au->advertised = FALSE;
4172 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4175 /* RFC 3030 CHUNKING */
4177 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4179 s = string_catn(s, &size, &ptr, smtp_code, 3);
4180 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4181 chunking_offered = TRUE;
4182 chunking_state = CHUNKING_OFFERED;
4185 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4186 if it has been included in the binary, and the host matches
4187 tls_advertise_hosts. We must *not* advertise if we are already in a
4188 secure connection. */
4191 if (tls_in.active < 0 &&
4192 verify_check_host(&tls_advertise_hosts) != FAIL)
4194 s = string_catn(s, &size, &ptr, smtp_code, 3);
4195 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4196 tls_advertised = TRUE;
4200 #ifndef DISABLE_PRDR
4201 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4204 s = string_catn(s, &size, &ptr, smtp_code, 3);
4205 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4210 if ( accept_8bitmime
4211 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4213 s = string_catn(s, &size, &ptr, smtp_code, 3);
4214 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4215 smtputf8_advertised = TRUE;
4219 /* Finish off the multiline reply with one that is always available. */
4221 s = string_catn(s, &size, &ptr, smtp_code, 3);
4222 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4225 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4231 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4235 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4240 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4241 memmove(cr, cr + 1, (ptr--) - (cr - s));
4242 debug_printf("SMTP>> %s", s);
4246 /* Reset the protocol and the state, abandoning any previous message. */
4248 (sender_host_address ? protocols : protocols_local)
4250 ? pextend + (sender_host_authenticated ? pauthed : 0)
4252 + (tls_in.active >= 0 ? pcrpted : 0)
4254 smtp_reset(reset_point);
4256 break; /* HELO/EHLO */
4259 /* The MAIL command requires an address as an operand. All we do
4260 here is to parse it for syntactic correctness. The form "<>" is
4261 a special case which converts into an empty string. The start/end
4262 pointers in the original are not used further for this address, as
4263 it is the canonical extracted address which is all that is kept. */
4267 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4268 was_rej_mail = TRUE; /* Reset if accepted */
4269 env_mail_type_t * mail_args; /* Sanity check & validate args */
4271 if (helo_required && !helo_seen)
4273 smtp_printf("503 HELO or EHLO required\r\n");
4274 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4275 "HELO/EHLO given", host_and_ident(FALSE));
4279 if (sender_address != NULL)
4281 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4282 US"sender already given");
4286 if (smtp_cmd_data[0] == 0)
4288 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4289 US"MAIL must have an address operand");
4293 /* Check to see if the limit for messages per connection would be
4294 exceeded by accepting further messages. */
4296 if (smtp_accept_max_per_connection > 0 &&
4297 smtp_mailcmd_count > smtp_accept_max_per_connection)
4299 smtp_printf("421 too many messages in this connection\r\n");
4300 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4301 "messages in one connection", host_and_ident(TRUE));
4305 /* Reset for start of message - even if this is going to fail, we
4306 obviously need to throw away any previous data. */
4308 smtp_reset(reset_point);
4310 sender_data = recipient_data = NULL;
4312 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4316 uschar *name, *value, *end;
4317 unsigned long int size;
4318 BOOL arg_error = FALSE;
4320 if (!extract_option(&name, &value)) break;
4322 for (mail_args = env_mail_type_list;
4323 mail_args->value != ENV_MAIL_OPT_NULL;
4326 if (strcmpic(name, mail_args->name) == 0)
4328 if (mail_args->need_value && strcmpic(value, US"") == 0)
4331 switch(mail_args->value)
4333 /* Handle SIZE= by reading the value. We don't do the check till later,
4334 in order to be able to log the sender address on failure. */
4335 case ENV_MAIL_OPT_SIZE:
4336 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4338 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4340 message_size = (int)size;
4346 /* If this session was initiated with EHLO and accept_8bitmime is set,
4347 Exim will have indicated that it supports the BODY=8BITMIME option. In
4348 fact, it does not support this according to the RFCs, in that it does not
4349 take any special action for forwarding messages containing 8-bit
4350 characters. That is why accept_8bitmime is not the default setting, but
4351 some sites want the action that is provided. We recognize both "8BITMIME"
4352 and "7BIT" as body types, but take no action. */
4353 case ENV_MAIL_OPT_BODY:
4354 if (accept_8bitmime) {
4355 if (strcmpic(value, US"8BITMIME") == 0)
4357 else if (strcmpic(value, US"7BIT") == 0)
4362 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4363 US"invalid data for BODY");
4366 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4372 /* Handle the two DSN options, but only if configured to do so (which
4373 will have caused "DSN" to be given in the EHLO response). The code itself
4374 is included only if configured in at build time. */
4376 case ENV_MAIL_OPT_RET:
4379 /* Check if RET has already been set */
4382 synprot_error(L_smtp_syntax_error, 501, NULL,
4383 US"RET can be specified once only");
4386 dsn_ret = strcmpic(value, US"HDRS") == 0
4388 : strcmpic(value, US"FULL") == 0
4391 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4392 /* Check for invalid invalid value, and exit with error */
4395 synprot_error(L_smtp_syntax_error, 501, NULL,
4396 US"Value for RET is invalid");
4401 case ENV_MAIL_OPT_ENVID:
4404 /* Check if the dsn envid has been already set */
4405 if (dsn_envid != NULL)
4407 synprot_error(L_smtp_syntax_error, 501, NULL,
4408 US"ENVID can be specified once only");
4411 dsn_envid = string_copy(value);
4412 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4416 /* Handle the AUTH extension. If the value given is not "<>" and either
4417 the ACL says "yes" or there is no ACL but the sending host is
4418 authenticated, we set it up as the authenticated sender. However, if the
4419 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4420 the condition is met. The value of AUTH is an xtext, which means that +,
4421 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4423 case ENV_MAIL_OPT_AUTH:
4424 if (Ustrcmp(value, "<>") != 0)
4429 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4431 /* Put back terminator overrides for error message */
4434 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4435 US"invalid data for AUTH");
4438 if (acl_smtp_mailauth == NULL)
4440 ignore_msg = US"client not authenticated";
4441 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4445 ignore_msg = US"rejected by ACL";
4446 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4447 &user_msg, &log_msg);
4453 if (authenticated_by == NULL ||
4454 authenticated_by->mail_auth_condition == NULL ||
4455 expand_check_condition(authenticated_by->mail_auth_condition,
4456 authenticated_by->name, US"authenticator"))
4457 break; /* Accept the AUTH */
4459 ignore_msg = US"server_mail_auth_condition failed";
4460 if (authenticated_id != NULL)
4461 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4462 ignore_msg, authenticated_id);
4467 authenticated_sender = NULL;
4468 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4469 value, host_and_ident(TRUE), ignore_msg);
4472 /* Should only get DEFER or ERROR here. Put back terminator
4473 overrides for error message */
4478 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4485 #ifndef DISABLE_PRDR
4486 case ENV_MAIL_OPT_PRDR:
4488 prdr_requested = TRUE;
4493 case ENV_MAIL_OPT_UTF8:
4494 if (smtputf8_advertised)
4496 int old_pool = store_pool;
4498 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4499 message_smtputf8 = allow_utf8_domains = TRUE;
4500 store_pool = POOL_PERM;
4501 received_protocol = string_sprintf("utf8%s", received_protocol);
4502 store_pool = old_pool;
4506 /* No valid option. Stick back the terminator characters and break
4507 the loop. Do the name-terminator second as extract_option sets
4508 value==name when it found no equal-sign.
4509 An error for a malformed address will occur. */
4510 case ENV_MAIL_OPT_NULL:
4518 /* Break out of for loop if switch() had bad argument or
4519 when start of the email address is reached */
4520 if (arg_error) break;
4523 /* If we have passed the threshold for rate limiting, apply the current
4524 delay, and update it for next time, provided this is a limited host. */
4526 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4527 verify_check_host(&smtp_ratelimit_hosts) == OK)
4529 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4530 smtp_delay_mail/1000.0);
4531 millisleep((int)smtp_delay_mail);
4532 smtp_delay_mail *= smtp_rlm_factor;
4533 if (smtp_delay_mail > (double)smtp_rlm_limit)
4534 smtp_delay_mail = (double)smtp_rlm_limit;
4537 /* Now extract the address, first applying any SMTP-time rewriting. The
4538 TRUE flag allows "<>" as a sender address. */
4540 raw_sender = rewrite_existflags & rewrite_smtp
4541 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4542 global_rewrite_rules)
4546 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4551 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4555 sender_address = raw_sender;
4557 /* If there is a configured size limit for mail, check that this message
4558 doesn't exceed it. The check is postponed to this point so that the sender
4561 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4563 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4564 log_write(L_size_reject,
4565 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4566 "message too big: size%s=%d max=%d",
4568 host_and_ident(TRUE),
4569 (message_size == INT_MAX)? ">" : "",
4571 thismessage_size_limit);
4572 sender_address = NULL;
4576 /* Check there is enough space on the disk unless configured not to.
4577 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4578 plus the current message - i.e. we accept the message only if it won't
4579 reduce the space below the threshold. Add 5000 to the size to allow for
4580 overheads such as the Received: line and storing of recipients, etc.
4581 By putting the check here, even when SIZE is not given, it allow VRFY
4582 and EXPN etc. to be used when space is short. */
4584 if (!receive_check_fs(
4585 (smtp_check_spool_space && message_size >= 0)?
4586 message_size + 5000 : 0))
4588 smtp_printf("452 Space shortage, please try later\r\n");
4589 sender_address = NULL;
4593 /* If sender_address is unqualified, reject it, unless this is a locally
4594 generated message, or the sending host or net is permitted to send
4595 unqualified addresses - typically local machines behaving as MUAs -
4596 in which case just qualify the address. The flag is set above at the start
4597 of the SMTP connection. */
4599 if (sender_domain == 0 && sender_address[0] != 0)
4601 if (allow_unqualified_sender)
4603 sender_domain = Ustrlen(sender_address) + 1;
4604 sender_address = rewrite_address_qualify(sender_address, FALSE);
4605 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4610 smtp_printf("501 %s: sender address must contain a domain\r\n",
4612 log_write(L_smtp_syntax_error,
4613 LOG_MAIN|LOG_REJECT,
4614 "unqualified sender rejected: <%s> %s%s",
4616 host_and_ident(TRUE),
4618 sender_address = NULL;
4623 /* Apply an ACL check if one is defined, before responding. Afterwards,
4624 when pipelining is not advertised, do another sync check in case the ACL
4625 delayed and the client started sending in the meantime. */
4629 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4630 if (rc == OK && !pipelining_advertised && !check_sync())
4636 if (rc == OK || rc == DISCARD)
4639 smtp_printf("%s%s%s", US"250 OK",
4640 #ifndef DISABLE_PRDR
4641 prdr_requested ? US", PRDR Requested" : US"",
4648 #ifndef DISABLE_PRDR
4650 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4652 smtp_user_msg(US"250", user_msg);
4654 smtp_delay_rcpt = smtp_rlr_base;
4655 recipients_discarded = (rc == DISCARD);
4656 was_rej_mail = FALSE;
4660 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4661 sender_address = NULL;
4666 /* The RCPT command requires an address as an operand. There may be any
4667 number of RCPT commands, specifying multiple recipients. We build them all
4668 into a data structure. The start/end values given by parse_extract_address
4669 are not used, as we keep only the extracted address. */
4674 was_rcpt = rcpt_in_progress = TRUE;
4676 /* There must be a sender address; if the sender was rejected and
4677 pipelining was advertised, we assume the client was pipelining, and do not
4678 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4679 get the same treatment. */
4681 if (sender_address == NULL)
4683 if (pipelining_advertised && last_was_rej_mail)
4685 smtp_printf("503 sender not yet given\r\n");
4686 was_rej_mail = TRUE;
4690 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4691 US"sender not yet given");
4692 was_rcpt = FALSE; /* Not a valid RCPT */
4698 /* Check for an operand */
4700 if (smtp_cmd_data[0] == 0)
4702 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4703 US"RCPT must have an address operand");
4708 /* Set the DSN flags orcpt and dsn_flags from the session*/
4714 uschar *name, *value;
4716 if (!extract_option(&name, &value))
4719 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4721 /* Check whether orcpt has been already set */
4724 synprot_error(L_smtp_syntax_error, 501, NULL,
4725 US"ORCPT can be specified once only");
4728 orcpt = string_copy(value);
4729 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4732 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4734 /* Check if the notify flags have been already set */
4737 synprot_error(L_smtp_syntax_error, 501, NULL,
4738 US"NOTIFY can be specified once only");
4741 if (strcmpic(value, US"NEVER") == 0)
4742 flags |= rf_notify_never;
4749 while (*pp != 0 && *pp != ',') pp++;
4750 if (*pp == ',') *pp++ = 0;
4751 if (strcmpic(p, US"SUCCESS") == 0)
4753 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4754 flags |= rf_notify_success;
4756 else if (strcmpic(p, US"FAILURE") == 0)
4758 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4759 flags |= rf_notify_failure;
4761 else if (strcmpic(p, US"DELAY") == 0)
4763 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4764 flags |= rf_notify_delay;
4768 /* Catch any strange values */
4769 synprot_error(L_smtp_syntax_error, 501, NULL,
4770 US"Invalid value for NOTIFY parameter");
4775 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4779 /* Unknown option. Stick back the terminator characters and break
4780 the loop. An error for a malformed address will occur. */
4784 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4791 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4792 as a recipient address */
4794 recipient = rewrite_existflags & rewrite_smtp
4795 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4796 global_rewrite_rules)
4799 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4800 &recipient_domain, FALSE)))
4802 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4807 /* If the recipient address is unqualified, reject it, unless this is a
4808 locally generated message. However, unqualified addresses are permitted
4809 from a configured list of hosts and nets - typically when behaving as
4810 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4811 really. The flag is set at the start of the SMTP connection.
4813 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4814 assumed this meant "reserved local part", but the revision of RFC 821 and
4815 friends now makes it absolutely clear that it means *mailbox*. Consequently
4816 we must always qualify this address, regardless. */
4818 if (!recipient_domain)
4819 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4826 /* Check maximum allowed */
4828 if (rcpt_count > recipients_max && recipients_max > 0)
4830 if (recipients_max_reject)
4833 smtp_printf("552 too many recipients\r\n");
4835 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4836 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4841 smtp_printf("452 too many recipients\r\n");
4843 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4844 "temporarily rejected: sender=<%s> %s", sender_address,
4845 host_and_ident(TRUE));
4852 /* If we have passed the threshold for rate limiting, apply the current
4853 delay, and update it for next time, provided this is a limited host. */
4855 if (rcpt_count > smtp_rlr_threshold &&
4856 verify_check_host(&smtp_ratelimit_hosts) == OK)
4858 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4859 smtp_delay_rcpt/1000.0);
4860 millisleep((int)smtp_delay_rcpt);
4861 smtp_delay_rcpt *= smtp_rlr_factor;
4862 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4863 smtp_delay_rcpt = (double)smtp_rlr_limit;
4866 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4867 for them. Otherwise, check the access control list for this recipient. As
4868 there may be a delay in this, re-check for a synchronization error
4869 afterwards, unless pipelining was advertised. */
4871 if (recipients_discarded)
4874 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4876 && !pipelining_advertised && !check_sync())
4879 /* The ACL was happy */
4884 smtp_user_msg(US"250", user_msg);
4886 smtp_printf("250 Accepted\r\n");
4887 receive_add_recipient(recipient, -1);
4889 /* Set the dsn flags in the recipients_list */
4890 recipients_list[recipients_count-1].orcpt = orcpt;
4891 recipients_list[recipients_count-1].dsn_flags = flags;
4893 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4894 recipients_list[recipients_count-1].orcpt,
4895 recipients_list[recipients_count-1].dsn_flags);
4898 /* The recipient was discarded */
4900 else if (rc == DISCARD)
4903 smtp_user_msg(US"250", user_msg);
4905 smtp_printf("250 Accepted\r\n");
4908 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4909 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4910 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4911 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4912 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4915 /* Either the ACL failed the address, or it was deferred. */
4919 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4920 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4925 /* The DATA command is legal only if it follows successful MAIL FROM
4926 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4927 not counted as a protocol error if it follows RCPT (which must have been
4928 rejected if there are no recipients.) This function is complete when a
4929 valid DATA command is encountered.
4931 Note concerning the code used: RFC 2821 says this:
4933 - If there was no MAIL, or no RCPT, command, or all such commands
4934 were rejected, the server MAY return a "command out of sequence"
4935 (503) or "no valid recipients" (554) reply in response to the
4938 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4939 because it is the same whether pipelining is in use or not.
4941 If all the RCPT commands that precede DATA provoked the same error message
4942 (often indicating some kind of system error), it is helpful to include it
4943 with the DATA rejection (an idea suggested by Tony Finch). */
4950 if (chunking_state != CHUNKING_OFFERED)
4952 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4953 US"BDAT command used when CHUNKING not advertised");
4957 /* grab size, endmarker */
4959 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
4961 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4962 US"missing size for BDAT command");
4965 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
4966 ? CHUNKING_LAST : CHUNKING_ACTIVE;
4967 chunking_data_left = chunking_datasize;
4968 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
4969 (int)chunking_state, chunking_data_left);
4971 lwr_receive_getc = receive_getc;
4972 lwr_receive_ungetc = receive_ungetc;
4973 receive_getc = bdat_getc;
4974 receive_ungetc = bdat_ungetc;
4982 DATA_BDAT: /* Common code for DATA and BDAT */
4983 if (!discarded && recipients_count <= 0)
4985 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4987 uschar *code = US"503";
4988 int len = Ustrlen(rcpt_smtp_response);
4989 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4991 /* Responses from smtp_printf() will have \r\n on the end */
4992 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4993 rcpt_smtp_response[len-2] = 0;
4994 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4996 if (pipelining_advertised && last_was_rcpt)
4997 smtp_printf("503 Valid RCPT command must precede %s\r\n",
4998 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5000 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5001 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5002 ? US"valid RCPT command must precede DATA"
5003 : US"valid RCPT command must precede BDAT");
5005 if (chunking_state > CHUNKING_OFFERED)
5010 if (toomany && recipients_max_reject)
5012 sender_address = NULL; /* This will allow a new MAIL without RSET */
5013 sender_address_unrewritten = NULL;
5014 smtp_printf("554 Too many recipients\r\n");
5018 if (chunking_state > CHUNKING_OFFERED)
5019 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5022 /* If there is an ACL, re-check the synchronization afterwards, since the
5023 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5024 to get the DATA command sent. */
5026 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5030 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5031 enable_dollar_recipients = TRUE;
5032 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5034 enable_dollar_recipients = FALSE;
5035 if (rc == OK && !check_sync())
5039 { /* Either the ACL failed the address, or it was deferred. */
5040 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5046 smtp_user_msg(US"354", user_msg);
5049 "354 Enter message, ending with \".\" on a line by itself\r\n");
5053 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5054 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5055 US &on, sizeof(on));
5058 message_ended = END_NOTENDED; /* Indicate in middle of data */
5069 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5070 &start, &end, &recipient_domain, FALSE)))
5072 smtp_printf("501 %s\r\n", errmess);
5076 if (!recipient_domain)
5077 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5081 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5082 &user_msg, &log_msg)) != OK)
5083 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5087 address_item * addr = deliver_make_addr(address, FALSE);
5089 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5090 -1, -1, NULL, NULL, NULL))
5093 s = string_sprintf("250 <%s> is deliverable", address);
5097 s = (addr->user_message != NULL)?
5098 string_sprintf("451 <%s> %s", address, addr->user_message) :
5099 string_sprintf("451 Cannot resolve <%s> at this time", address);
5103 s = (addr->user_message != NULL)?
5104 string_sprintf("550 <%s> %s", address, addr->user_message) :
5105 string_sprintf("550 <%s> is not deliverable", address);
5106 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5107 smtp_cmd_argument, host_and_ident(TRUE));
5111 smtp_printf("%s\r\n", s);
5119 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5121 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5124 BOOL save_log_testing_mode = log_testing_mode;
5125 address_test_mode = log_testing_mode = TRUE;
5126 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5127 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5129 address_test_mode = FALSE;
5130 log_testing_mode = save_log_testing_mode; /* true for -bh */
5139 if (!tls_advertised)
5141 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5142 US"STARTTLS command used when not advertised");
5146 /* Apply an ACL check if one is defined */
5148 if ( acl_smtp_starttls
5149 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5150 &user_msg, &log_msg)) != OK
5153 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5157 /* RFC 2487 is not clear on when this command may be sent, though it
5158 does state that all information previously obtained from the client
5159 must be discarded if a TLS session is started. It seems reasonable to
5160 do an implied RSET when STARTTLS is received. */
5162 incomplete_transaction_log(US"STARTTLS");
5163 smtp_reset(reset_point);
5165 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5167 /* There's an attack where more data is read in past the STARTTLS command
5168 before TLS is negotiated, then assumed to be part of the secure session
5169 when used afterwards; we use segregated input buffers, so are not
5170 vulnerable, but we want to note when it happens and, for sheer paranoia,
5171 ensure that the buffer is "wiped".
5172 Pipelining sync checks will normally have protected us too, unless disabled
5173 by configuration. */
5175 if (receive_smtp_buffered())
5178 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5179 if (tls_in.active < 0)
5180 smtp_inend = smtp_inptr = smtp_inbuffer;
5181 /* and if TLS is already active, tls_server_start() should fail */
5184 /* There is nothing we value in the input buffer and if TLS is successfully
5185 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5186 fresh content into it. The buffer contains arbitrary content from an
5187 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5188 It seems safest to just wipe away the content rather than leave it as a
5189 target to jump to. */
5191 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5193 /* Attempt to start up a TLS session, and if successful, discard all
5194 knowledge that was obtained previously. At least, that's what the RFC says,
5195 and that's what happens by default. However, in order to work round YAEB,
5196 there is an option to remember the esmtp state. Sigh.
5198 We must allow for an extra EHLO command and an extra AUTH command after
5199 STARTTLS that don't add to the nonmail command count. */
5202 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5204 if (!tls_remember_esmtp)
5205 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5206 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5207 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5208 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5209 if (sender_helo_name != NULL)
5211 store_free(sender_helo_name);
5212 sender_helo_name = NULL;
5213 host_build_sender_fullhost(); /* Rebuild */
5214 set_process_info("handling incoming TLS connection from %s",
5215 host_and_ident(FALSE));
5218 (sender_host_address ? protocols : protocols_local)
5220 ? pextend + (sender_host_authenticated ? pauthed : 0)
5222 + (tls_in.active >= 0 ? pcrpted : 0)
5225 sender_host_authenticated = NULL;
5226 authenticated_id = NULL;
5227 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5228 DEBUG(D_tls) debug_printf("TLS active\n");
5229 break; /* Successful STARTTLS */
5232 (void) smtp_log_tls_fail(s);
5234 /* Some local configuration problem was discovered before actually trying
5235 to do a TLS handshake; give a temporary error. */
5239 smtp_printf("454 TLS currently unavailable\r\n");
5243 /* Hard failure. Reject everything except QUIT or closed connection. One
5244 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5245 set, but we must still reject all incoming commands. */
5247 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5248 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5251 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5252 smtp_get_connection_info());
5253 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5257 /* It is perhaps arguable as to which exit ACL should be called here,
5258 but as it is probably a situation that almost never arises, it
5259 probably doesn't matter. We choose to call the real QUIT ACL, which in
5260 some sense is perhaps "right". */
5265 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5266 &log_msg)) == ERROR))
5267 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5270 smtp_respond(US"221", 3, TRUE, user_msg);
5272 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
5273 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5274 smtp_get_connection_info());
5279 smtp_printf("554 Security failure\r\n");
5282 tls_close(TRUE, TRUE);
5287 /* The ACL for QUIT is provided for gathering statistical information or
5288 similar; it does not affect the response code, but it can supply a custom
5292 smtp_quit_handler(&user_msg, &log_msg);
5298 smtp_rset_handler();
5299 smtp_reset(reset_point);
5306 smtp_printf("250 OK\r\n");
5310 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5311 used, a check will be done for permitted hosts. Show STARTTLS only if not
5312 already in a TLS session and if it would be advertised in the EHLO
5317 smtp_printf("214-Commands supported:\r\n");
5321 Ustrcat(buffer, " AUTH");
5323 if (tls_in.active < 0 &&
5324 verify_check_host(&tls_advertise_hosts) != FAIL)
5325 Ustrcat(buffer, " STARTTLS");
5327 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5328 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5329 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5330 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5331 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5332 smtp_printf("214%s\r\n", buffer);
5338 incomplete_transaction_log(US"connection lost");
5339 smtp_notquit_exit(US"connection-lost", US"421",
5340 US"%s lost input connection", smtp_active_hostname);
5342 /* Don't log by default unless in the middle of a message, as some mailers
5343 just drop the call rather than sending QUIT, and it clutters up the logs.
5346 if (sender_address != NULL || recipients_count > 0)
5347 log_write(L_lost_incoming_connection,
5349 "unexpected %s while reading SMTP command from %s%s",
5350 sender_host_unknown? "EOF" : "disconnection",
5351 host_and_ident(FALSE), smtp_read_error);
5353 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5354 smtp_get_connection_info(), smtp_read_error);
5362 if (sender_address != NULL)
5364 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5365 US"ETRN is not permitted inside a transaction");
5369 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5370 host_and_ident(FALSE));
5372 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5373 &user_msg, &log_msg)) != OK)
5375 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5379 /* Compute the serialization key for this command. */
5381 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5383 /* If a command has been specified for running as a result of ETRN, we
5384 permit any argument to ETRN. If not, only the # standard form is permitted,
5385 since that is strictly the only kind of ETRN that can be implemented
5386 according to the RFC. */
5388 if (smtp_etrn_command != NULL)
5392 etrn_command = smtp_etrn_command;
5393 deliver_domain = smtp_cmd_data;
5394 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5395 US"ETRN processing", &error);
5396 deliver_domain = NULL;
5399 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5401 smtp_printf("458 Internal failure\r\n");
5406 /* Else set up to call Exim with the -R option. */
5410 if (*smtp_cmd_data++ != '#')
5412 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5413 US"argument must begin with #");
5416 etrn_command = US"exim -R";
5417 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5418 *queue_name ? 4 : 2,
5419 US"-R", smtp_cmd_data,
5420 US"-MCG", queue_name);
5423 /* If we are host-testing, don't actually do anything. */
5429 debug_printf("ETRN command is: %s\n", etrn_command);
5430 debug_printf("ETRN command execution skipped\n");
5432 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5433 else smtp_user_msg(US"250", user_msg);
5438 /* If ETRN queue runs are to be serialized, check the database to
5439 ensure one isn't already running. */
5441 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5443 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
5447 /* Fork a child process and run the command. We don't want to have to
5448 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5449 forking. It should be set that way anyway for external incoming SMTP,
5450 but we save and restore to be tidy. If serialization is required, we
5451 actually run the command in yet another process, so we can wait for it
5452 to complete and then remove the serialization lock. */
5454 oldsignal = signal(SIGCHLD, SIG_IGN);
5456 if ((pid = fork()) == 0)
5458 smtp_input = FALSE; /* This process is not associated with the */
5459 (void)fclose(smtp_in); /* SMTP call any more. */
5460 (void)fclose(smtp_out);
5462 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5464 /* If not serializing, do the exec right away. Otherwise, fork down
5465 into another process. */
5467 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5469 DEBUG(D_exec) debug_print_argv(argv);
5470 exim_nullstd(); /* Ensure std{in,out,err} exist */
5471 execv(CS argv[0], (char *const *)argv);
5472 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5473 etrn_command, strerror(errno));
5474 _exit(EXIT_FAILURE); /* paranoia */
5477 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5478 is, we are in the first subprocess, after forking again. All we can do
5479 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5480 complete, before removing the serialization. */
5483 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5484 "failed: %s", strerror(errno));
5488 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5490 (void)wait(&status);
5491 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5495 enq_end(etrn_serialize_key);
5496 _exit(EXIT_SUCCESS);
5499 /* Back in the top level SMTP process. Check that we started a subprocess
5500 and restore the signal state. */
5504 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5506 smtp_printf("458 Unable to fork process\r\n");
5507 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5511 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5512 else smtp_user_msg(US"250", user_msg);
5515 signal(SIGCHLD, oldsignal);
5520 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5521 US"unexpected argument data");
5525 /* This currently happens only for NULLs, but could be extended. */
5528 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5529 US"NULL character(s) present (shown as '?')");
5530 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5536 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5537 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5538 c = smtp_inend - smtp_inptr;
5539 if (c > 150) c = 150;
5541 incomplete_transaction_log(US"sync failure");
5542 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5543 "(next input sent too soon: pipelining was%s advertised): "
5544 "rejected \"%s\" %s next input=\"%s\"",
5545 pipelining_advertised? "" : " not",
5546 smtp_cmd_buffer, host_and_ident(TRUE),
5547 string_printing(smtp_inptr));
5548 smtp_notquit_exit(US"synchronization-error", US"554",
5549 US"SMTP synchronization error");
5550 done = 1; /* Pretend eof - drops connection */
5554 case TOO_MANY_NONMAIL_CMD:
5555 s = smtp_cmd_buffer;
5556 while (*s != 0 && !isspace(*s)) s++;
5557 incomplete_transaction_log(US"too many non-mail commands");
5558 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5559 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5560 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5561 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5562 done = 1; /* Pretend eof - drops connection */
5565 #ifdef SUPPORT_PROXY
5566 case PROXY_FAIL_IGNORE_CMD:
5567 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5572 if (unknown_command_count++ >= smtp_max_unknown_commands)
5574 log_write(L_smtp_syntax_error, LOG_MAIN,
5575 "SMTP syntax error in \"%s\" %s %s",
5576 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5577 US"unrecognized command");
5578 incomplete_transaction_log(US"unrecognized command");
5579 smtp_notquit_exit(US"bad-commands", US"500",
5580 US"Too many unrecognized commands");
5582 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5583 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5584 string_printing(smtp_cmd_buffer));
5587 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5588 US"unrecognized command");
5592 /* This label is used by goto's inside loops that want to break out to
5593 the end of the command-processing loop. */
5596 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5597 last_was_rcpt = was_rcpt; /* protocol error handling */
5601 return done - 2; /* Convert yield values */
5606 /* End of smtp_in.c */