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 */
2225 /*************************************************
2226 * Start an SMTP session *
2227 *************************************************/
2229 /* This function is called at the start of an SMTP session. Thereafter,
2230 smtp_setup_msg() is called to initiate each separate message. This
2231 function does host-specific testing, and outputs the banner line.
2234 Returns: FALSE if the session can not continue; something has
2235 gone wrong, or the connection to the host is blocked
2239 smtp_start_session(void)
2243 uschar *user_msg, *log_msg;
2247 smtp_connection_start = time(NULL);
2248 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2249 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2252 /* Default values for certain variables */
2254 helo_seen = esmtp = helo_accept_junk = FALSE;
2255 smtp_mailcmd_count = 0;
2256 count_nonmail = TRUE_UNSET;
2257 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2258 smtp_delay_mail = smtp_rlm_base;
2259 auth_advertised = FALSE;
2260 pipelining_advertised = FALSE;
2261 pipelining_enable = TRUE;
2262 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2263 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2265 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2266 authentication settings from -oMaa to remain in force. */
2268 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2269 authenticated_by = NULL;
2272 tls_in.cipher = tls_in.peerdn = NULL;
2273 tls_in.ourcert = tls_in.peercert = NULL;
2275 tls_in.ocsp = OCSP_NOT_REQ;
2276 tls_advertised = FALSE;
2278 dsn_advertised = FALSE;
2280 smtputf8_advertised = FALSE;
2283 /* Reset ACL connection variables */
2287 /* Allow for trailing 0 in the command and data buffers. */
2289 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2290 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2291 "malloc() failed for SMTP command buffer");
2293 smtp_cmd_buffer[0] = 0;
2294 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2296 /* For batched input, the protocol setting can be overridden from the
2297 command line by a trusted caller. */
2299 if (smtp_batched_input)
2301 if (!received_protocol) received_protocol = US"local-bsmtp";
2304 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2305 reset later if any of EHLO/AUTH/STARTTLS are received. */
2309 (sender_host_address ? protocols : protocols_local) [pnormal];
2311 /* Set up the buffer for inputting using direct read() calls, and arrange to
2312 call the local functions instead of the standard C ones. */
2314 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2315 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2317 receive_getc = smtp_getc;
2318 receive_get_cache = smtp_get_cache;
2319 receive_ungetc = smtp_ungetc;
2320 receive_feof = smtp_feof;
2321 receive_ferror = smtp_ferror;
2322 receive_smtp_buffered = smtp_buffered;
2323 smtp_inptr = smtp_inend = smtp_inbuffer;
2324 smtp_had_eof = smtp_had_error = 0;
2326 /* Set up the message size limit; this may be host-specific */
2328 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2329 if (expand_string_message != NULL)
2331 if (thismessage_size_limit == -1)
2332 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2333 "%s", expand_string_message);
2335 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2336 "%s", expand_string_message);
2337 smtp_closedown(US"Temporary local problem - please try later");
2341 /* When a message is input locally via the -bs or -bS options, sender_host_
2342 unknown is set unless -oMa was used to force an IP address, in which case it
2343 is checked like a real remote connection. When -bs is used from inetd, this
2344 flag is not set, causing the sending host to be checked. The code that deals
2345 with IP source routing (if configured) is never required for -bs or -bS and
2346 the flag sender_host_notsocket is used to suppress it.
2348 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2349 reserve for certain hosts and/or networks. */
2351 if (!sender_host_unknown)
2354 BOOL reserved_host = FALSE;
2356 /* Look up IP options (source routing info) on the socket if this is not an
2357 -oMa "host", and if any are found, log them and drop the connection.
2359 Linux (and others now, see below) is different to everyone else, so there
2360 has to be some conditional compilation here. Versions of Linux before 2.1.15
2361 used a structure whose name was "options". Somebody finally realized that
2362 this name was silly, and it got changed to "ip_options". I use the
2363 newer name here, but there is a fudge in the script that sets up os.h
2364 to define a macro in older Linux systems.
2366 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2367 glibc 2, which has chosen ip_opts for the structure name. This is now
2368 really a glibc thing rather than a Linux thing, so the condition name
2369 has been changed to reflect this. It is relevant also to GNU/Hurd.
2371 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2372 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2373 a special macro defined in the os.h file.
2375 Some DGUX versions on older hardware appear not to support IP options at
2376 all, so there is now a general macro which can be set to cut out this
2379 How to do this properly in IPv6 is not yet known. */
2381 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2383 #ifdef GLIBC_IP_OPTIONS
2384 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2389 #elif defined DARWIN_IP_OPTIONS
2395 if (!host_checking && !sender_host_notsocket)
2398 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2399 struct ip_options *ipopt = store_get(optlen);
2401 struct ip_opts ipoptblock;
2402 struct ip_opts *ipopt = &ipoptblock;
2403 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2405 struct ipoption ipoptblock;
2406 struct ipoption *ipopt = &ipoptblock;
2407 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2410 /* Occasional genuine failures of getsockopt() have been seen - for
2411 example, "reset by peer". Therefore, just log and give up on this
2412 call, unless the error is ENOPROTOOPT. This error is given by systems
2413 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2414 of writing. So for that error, carry on - we just can't do an IP options
2417 DEBUG(D_receive) debug_printf("checking for IP options\n");
2419 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2422 if (errno != ENOPROTOOPT)
2424 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2425 host_and_ident(FALSE), strerror(errno));
2426 smtp_printf("451 SMTP service not available\r\n");
2431 /* Deal with any IP options that are set. On the systems I have looked at,
2432 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2433 more logging data than will fit in big_buffer. Nevertheless, after somebody
2434 questioned this code, I've added in some paranoid checking. */
2436 else if (optlen > 0)
2438 uschar *p = big_buffer;
2439 uschar *pend = big_buffer + big_buffer_size;
2440 uschar *opt, *adptr;
2442 struct in_addr addr;
2445 uschar *optstart = (uschar *)(ipopt->__data);
2447 uschar *optstart = (uschar *)(ipopt->ip_opts);
2449 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2452 DEBUG(D_receive) debug_printf("IP options exist\n");
2454 Ustrcpy(p, "IP options on incoming call:");
2457 for (opt = optstart; opt != NULL &&
2458 opt < (uschar *)(ipopt) + optlen;)
2472 if (!string_format(p, pend-p, " %s [@%s",
2473 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2475 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2477 inet_ntoa(ipopt->ip_dst)))
2479 inet_ntoa(ipopt->ipopt_dst)))
2487 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2489 while (optcount-- > 0)
2491 memcpy(&addr, adptr, sizeof(addr));
2492 if (!string_format(p, pend - p - 1, "%s%s",
2493 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2499 adptr += sizeof(struct in_addr);
2508 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2511 for (i = 0; i < opt[1]; i++)
2513 sprintf(CS p, "%2.2x ", opt[i]);
2524 log_write(0, LOG_MAIN, "%s", big_buffer);
2526 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2528 log_write(0, LOG_MAIN|LOG_REJECT,
2529 "connection from %s refused (IP options)", host_and_ident(FALSE));
2531 smtp_printf("554 SMTP service not available\r\n");
2535 /* Length of options = 0 => there are no options */
2537 else DEBUG(D_receive) debug_printf("no IP options found\n");
2539 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2541 /* Set keep-alive in socket options. The option is on by default. This
2542 setting is an attempt to get rid of some hanging connections that stick in
2543 read() when the remote end (usually a dialup) goes away. */
2545 if (smtp_accept_keepalive && !sender_host_notsocket)
2546 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2548 /* If the current host matches host_lookup, set the name by doing a
2549 reverse lookup. On failure, sender_host_name will be NULL and
2550 host_lookup_failed will be TRUE. This may or may not be serious - optional
2553 if (verify_check_host(&host_lookup) == OK)
2555 (void)host_name_lookup();
2556 host_build_sender_fullhost();
2559 /* Delay this until we have the full name, if it is looked up. */
2561 set_process_info("handling incoming connection from %s",
2562 host_and_ident(FALSE));
2564 /* Expand smtp_receive_timeout, if needed */
2566 if (smtp_receive_timeout_s)
2569 if ( !(exp = expand_string(smtp_receive_timeout_s))
2571 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2573 log_write(0, LOG_MAIN|LOG_PANIC,
2574 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2577 /* Test for explicit connection rejection */
2579 if (verify_check_host(&host_reject_connection) == OK)
2581 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2582 "from %s (host_reject_connection)", host_and_ident(FALSE));
2583 smtp_printf("554 SMTP service not available\r\n");
2587 /* Test with TCP Wrappers if so configured. There is a problem in that
2588 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2589 such as disks dying. In these cases, it is desirable to reject with a 4xx
2590 error instead of a 5xx error. There isn't a "right" way to detect such
2591 problems. The following kludge is used: errno is zeroed before calling
2592 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2593 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2596 #ifdef USE_TCP_WRAPPERS
2598 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2599 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2600 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2601 expand_string_message);
2603 if (!hosts_ctl(tcp_wrappers_name,
2604 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2605 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2606 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2608 if (errno == 0 || errno == ENOENT)
2610 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2611 log_write(L_connection_reject,
2612 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2613 "(tcp wrappers)", host_and_ident(FALSE));
2614 smtp_printf("554 SMTP service not available\r\n");
2618 int save_errno = errno;
2619 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2620 "errno value %d\n", save_errno);
2621 log_write(L_connection_reject,
2622 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2623 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2624 smtp_printf("451 Temporary local problem - please try later\r\n");
2630 /* Check for reserved slots. The value of smtp_accept_count has already been
2631 incremented to include this process. */
2633 if (smtp_accept_max > 0 &&
2634 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2636 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2638 log_write(L_connection_reject,
2639 LOG_MAIN, "temporarily refused connection from %s: not in "
2640 "reserve list: connected=%d max=%d reserve=%d%s",
2641 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2642 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2643 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2644 "please try again later\r\n", smtp_active_hostname);
2647 reserved_host = TRUE;
2650 /* If a load level above which only messages from reserved hosts are
2651 accepted is set, check the load. For incoming calls via the daemon, the
2652 check is done in the superior process if there are no reserved hosts, to
2653 save a fork. In all cases, the load average will already be available
2654 in a global variable at this point. */
2656 if (smtp_load_reserve >= 0 &&
2657 load_average > smtp_load_reserve &&
2659 verify_check_host(&smtp_reserve_hosts) != OK)
2661 log_write(L_connection_reject,
2662 LOG_MAIN, "temporarily refused connection from %s: not in "
2663 "reserve list and load average = %.2f", host_and_ident(FALSE),
2664 (double)load_average/1000.0);
2665 smtp_printf("421 %s: Too much load; please try again later\r\n",
2666 smtp_active_hostname);
2670 /* Determine whether unqualified senders or recipients are permitted
2671 for this host. Unfortunately, we have to do this every time, in order to
2672 set the flags so that they can be inspected when considering qualifying
2673 addresses in the headers. For a site that permits no qualification, this
2674 won't take long, however. */
2676 allow_unqualified_sender =
2677 verify_check_host(&sender_unqualified_hosts) == OK;
2679 allow_unqualified_recipient =
2680 verify_check_host(&recipient_unqualified_hosts) == OK;
2682 /* Determine whether HELO/EHLO is required for this host. The requirement
2683 can be hard or soft. */
2685 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2687 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2689 /* Determine whether this hosts is permitted to send syntactic junk
2690 after a HELO or EHLO command. */
2692 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2695 /* For batch SMTP input we are now done. */
2697 if (smtp_batched_input) return TRUE;
2699 /* If valid Proxy Protocol source is connecting, set up session.
2700 * Failure will not allow any SMTP function other than QUIT. */
2702 #ifdef SUPPORT_PROXY
2703 proxy_session = FALSE;
2704 proxy_session_failed = FALSE;
2705 if (check_proxy_protocol_host())
2706 setup_proxy_protocol_host();
2709 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2710 smtps port for use with older style SSL MTAs. */
2713 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2717 /* Run the connect ACL if it exists */
2720 if (acl_smtp_connect)
2723 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2726 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2731 /* Output the initial message for a two-way SMTP connection. It may contain
2732 newlines, which then cause a multi-line response to be given. */
2734 code = US"220"; /* Default status code */
2735 esc = US""; /* Default extended status code */
2736 esclen = 0; /* Length of esc */
2740 if (!(s = expand_string(smtp_banner)))
2741 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2742 "failed: %s", smtp_banner, expand_string_message);
2748 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2752 esclen = codelen - 4;
2756 /* Remove any terminating newlines; might as well remove trailing space too */
2759 while (p > s && isspace(p[-1])) p--;
2762 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2763 is all contained in a single IP packet. The original code wrote out the
2764 greeting using several calls to fprint/fputc, and on busy servers this could
2765 cause it to be split over more than one packet - which caused CC:Mail to fall
2766 over when it got the second part of the greeting after sending its first
2767 command. Sigh. To try to avoid this, build the complete greeting message
2768 first, and output it in one fell swoop. This gives a better chance of it
2769 ending up as a single packet. */
2771 ss = store_get(size);
2775 do /* At least once, in case we have an empty string */
2778 uschar *linebreak = Ustrchr(p, '\n');
2779 ss = string_catn(ss, &size, &ptr, code, 3);
2780 if (linebreak == NULL)
2783 ss = string_catn(ss, &size, &ptr, US" ", 1);
2787 len = linebreak - p;
2788 ss = string_catn(ss, &size, &ptr, US"-", 1);
2790 ss = string_catn(ss, &size, &ptr, esc, esclen);
2791 ss = string_catn(ss, &size, &ptr, p, len);
2792 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2794 if (linebreak != NULL) p++;
2798 ss[ptr] = 0; /* string_cat leaves room for this */
2800 /* Before we write the banner, check that there is no input pending, unless
2801 this synchronisation check is disabled. */
2805 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2806 "synchronization error (input sent without waiting for greeting): "
2807 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2808 string_printing(smtp_inptr));
2809 smtp_printf("554 SMTP synchronization error\r\n");
2813 /* Now output the banner */
2815 smtp_printf("%s", ss);
2823 /*************************************************
2824 * Handle SMTP syntax and protocol errors *
2825 *************************************************/
2827 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2828 to do so. Then transmit the error response. The return value depends on the
2829 number of syntax and protocol errors in this SMTP session.
2832 type error type, given as a log flag bit
2833 code response code; <= 0 means don't send a response
2834 data data to reflect in the response (can be NULL)
2835 errmess the error message
2837 Returns: -1 limit of syntax/protocol errors NOT exceeded
2838 +1 limit of syntax/protocol errors IS exceeded
2840 These values fit in with the values of the "done" variable in the main
2841 processing loop in smtp_setup_msg(). */
2844 synprot_error(int type, int code, uschar *data, uschar *errmess)
2848 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2849 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2850 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2852 if (++synprot_error_count > smtp_max_synprot_errors)
2855 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2856 "syntax or protocol errors (last command was \"%s\")",
2857 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2862 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2863 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2865 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2874 /*************************************************
2875 * Send SMTP response, possibly multiline *
2876 *************************************************/
2878 /* There are, it seems, broken clients out there that cannot handle multiline
2879 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2880 output nothing for non-final calls, and only the first line for anything else.
2883 code SMTP code, may involve extended status codes
2884 codelen length of smtp code; if > 4 there's an ESC
2885 final FALSE if the last line isn't the final line
2886 msg message text, possibly containing newlines
2892 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2897 if (!final && no_multiline_responses) return;
2902 esclen = codelen - 4;
2905 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2906 have had the same. Note: this code is also present in smtp_printf(). It would
2907 be tidier to have it only in one place, but when it was added, it was easier to
2908 do it that way, so as not to have to mess with the code for the RCPT command,
2909 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2911 if (rcpt_in_progress)
2913 if (rcpt_smtp_response == NULL)
2914 rcpt_smtp_response = string_copy(msg);
2915 else if (rcpt_smtp_response_same &&
2916 Ustrcmp(rcpt_smtp_response, msg) != 0)
2917 rcpt_smtp_response_same = FALSE;
2918 rcpt_in_progress = FALSE;
2921 /* Not output the message, splitting it up into multiple lines if necessary. */
2925 uschar *nl = Ustrchr(msg, '\n');
2928 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2931 else if (nl[1] == 0 || no_multiline_responses)
2933 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2934 (int)(nl - msg), msg);
2939 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2941 while (isspace(*msg)) msg++;
2949 /*************************************************
2950 * Parse user SMTP message *
2951 *************************************************/
2953 /* This function allows for user messages overriding the response code details
2954 by providing a suitable response code string at the start of the message
2955 user_msg. Check the message for starting with a response code and optionally an
2956 extended status code. If found, check that the first digit is valid, and if so,
2957 change the code pointer and length to use the replacement. An invalid code
2958 causes a panic log; in this case, if the log messages is the same as the user
2959 message, we must also adjust the value of the log message to show the code that
2960 is actually going to be used (the original one).
2962 This function is global because it is called from receive.c as well as within
2965 Note that the code length returned includes the terminating whitespace
2966 character, which is always included in the regex match.
2969 code SMTP code, may involve extended status codes
2970 codelen length of smtp code; if > 4 there's an ESC
2972 log_msg optional log message, to be adjusted with the new SMTP code
2973 check_valid if true, verify the response code
2979 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2985 if (!msg || !*msg) return;
2987 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2988 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2990 if (check_valid && (*msg)[0] != (*code)[0])
2992 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2993 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2994 if (log_msg != NULL && *log_msg == *msg)
2995 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3000 *codelen = ovector[1]; /* Includes final space */
3002 *msg += ovector[1]; /* Chop the code off the message */
3009 /*************************************************
3010 * Handle an ACL failure *
3011 *************************************************/
3013 /* This function is called when acl_check() fails. As well as calls from within
3014 this module, it is called from receive.c for an ACL after DATA. It sorts out
3015 logging the incident, and sets up the error response. A message containing
3016 newlines is turned into a multiline SMTP response, but for logging, only the
3019 There's a table of default permanent failure response codes to use in
3020 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3021 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3022 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3023 state, because there are broken clients that try VRFY before RCPT. A 5xx
3024 response should be given only when the address is positively known to be
3025 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3026 no explicit code, but if there is one we let it know best.
3027 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3029 From Exim 4.63, it is possible to override the response code details by
3030 providing a suitable response code string at the start of the message provided
3031 in user_msg. The code's first digit is checked for validity.
3034 where where the ACL was called from
3036 user_msg a message that can be included in an SMTP response
3037 log_msg a message for logging
3039 Returns: 0 in most cases
3040 2 if the failure code was FAIL_DROP, in which case the
3041 SMTP connection should be dropped (this value fits with the
3042 "done" variable in smtp_setup_msg() below)
3046 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3048 BOOL drop = rc == FAIL_DROP;
3052 uschar *sender_info = US"";
3054 #ifdef WITH_CONTENT_SCAN
3055 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3057 where == ACL_WHERE_PREDATA ? US"DATA" :
3058 where == ACL_WHERE_DATA ? US"after DATA" :
3059 #ifndef DISABLE_PRDR
3060 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3063 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3064 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3066 if (drop) rc = FAIL;
3068 /* Set the default SMTP code, and allow a user message to change it. */
3070 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3071 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3072 where != ACL_WHERE_VRFY);
3074 /* We used to have sender_address here; however, there was a bug that was not
3075 updating sender_address after a rewrite during a verify. When this bug was
3076 fixed, sender_address at this point became the rewritten address. I'm not sure
3077 this is what should be logged, so I've changed to logging the unrewritten
3078 address to retain backward compatibility. */
3080 #ifndef WITH_CONTENT_SCAN
3081 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3083 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3086 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3087 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3088 sender_host_authenticated ? US" A=" : US"",
3089 sender_host_authenticated ? sender_host_authenticated : US"",
3090 sender_host_authenticated && authenticated_id ? US":" : US"",
3091 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3095 /* If there's been a sender verification failure with a specific message, and
3096 we have not sent a response about it yet, do so now, as a preliminary line for
3097 failures, but not defers. However, always log it for defer, and log it for fail
3098 unless the sender_verify_fail log selector has been turned off. */
3100 if (sender_verified_failed &&
3101 !testflag(sender_verified_failed, af_sverify_told))
3103 BOOL save_rcpt_in_progress = rcpt_in_progress;
3104 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3106 setflag(sender_verified_failed, af_sverify_told);
3108 if (rc != FAIL || LOGGING(sender_verify_fail))
3109 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3110 host_and_ident(TRUE),
3111 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3112 sender_verified_failed->address,
3113 (sender_verified_failed->message == NULL)? US"" :
3114 string_sprintf(": %s", sender_verified_failed->message));
3116 if (rc == FAIL && sender_verified_failed->user_message)
3117 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3118 testflag(sender_verified_failed, af_verify_pmfail)?
3119 "Postmaster verification failed while checking <%s>\n%s\n"
3120 "Several RFCs state that you are required to have a postmaster\n"
3121 "mailbox for each mail domain. This host does not accept mail\n"
3122 "from domains whose servers reject the postmaster address."
3124 testflag(sender_verified_failed, af_verify_nsfail)?
3125 "Callback setup failed while verifying <%s>\n%s\n"
3126 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3127 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3128 "RFC requirements, and stops you from receiving standard bounce\n"
3129 "messages. This host does not accept mail from domains whose servers\n"
3132 "Verification failed for <%s>\n%s",
3133 sender_verified_failed->address,
3134 sender_verified_failed->user_message));
3136 rcpt_in_progress = save_rcpt_in_progress;
3139 /* Sort out text for logging */
3141 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3142 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3144 /* Send permanent failure response to the command, but the code used isn't
3145 always a 5xx one - see comments at the start of this function. If the original
3146 rc was FAIL_DROP we drop the connection and yield 2. */
3149 smtp_respond(smtp_code, codelen, TRUE,
3150 user_msg ? user_msg : US"Administrative prohibition");
3152 /* Send temporary failure response to the command. Don't give any details,
3153 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3154 verb, and for a header verify when smtp_return_error_details is set.
3156 This conditional logic is all somewhat of a mess because of the odd
3157 interactions between temp_details and return_error_details. One day it should
3158 be re-implemented in a tidier fashion. */
3161 if (acl_temp_details && user_msg)
3163 if ( smtp_return_error_details
3164 && sender_verified_failed
3165 && sender_verified_failed->message
3167 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3169 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3172 smtp_respond(smtp_code, codelen, TRUE,
3173 US"Temporary local problem - please try later");
3175 /* Log the incident to the logs that are specified by log_reject_target
3176 (default main, reject). This can be empty to suppress logging of rejections. If
3177 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3178 is closing if required and return 2. */
3180 if (log_reject_target != 0)
3183 uschar * tls = s_tlslog(NULL, NULL, NULL);
3184 if (!tls) tls = US"";
3186 uschar * tls = US"";
3188 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3189 log_reject_target, "%s%s%s %s%srejected %s%s",
3190 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3191 host_and_ident(TRUE),
3194 rc == FAIL ? US"" : US"temporarily ",
3198 if (!drop) return 0;
3200 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3201 smtp_get_connection_info());
3203 /* Run the not-quit ACL, but without any custom messages. This should not be a
3204 problem, because we get here only if some other ACL has issued "drop", and
3205 in that case, *its* custom messages will have been used above. */
3207 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3214 /*************************************************
3215 * Handle SMTP exit when QUIT is not given *
3216 *************************************************/
3218 /* This function provides a logging/statistics hook for when an SMTP connection
3219 is dropped on the floor or the other end goes away. It's a global function
3220 because it's called from receive.c as well as this module. As well as running
3221 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3222 response, either with a custom message from the ACL, or using a default. There
3223 is one case, however, when no message is output - after "drop". In that case,
3224 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3225 passed to this function.
3227 In case things go wrong while processing this function, causing an error that
3228 may re-enter this function, there is a recursion check.
3231 reason What $smtp_notquit_reason will be set to in the ACL;
3232 if NULL, the ACL is not run
3233 code The error code to return as part of the response
3234 defaultrespond The default message if there's no user_msg
3240 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3243 uschar *user_msg = NULL;
3244 uschar *log_msg = NULL;
3246 /* Check for recursive acll */
3248 if (smtp_exit_function_called)
3250 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3254 smtp_exit_function_called = TRUE;
3256 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3258 if (acl_smtp_notquit && reason)
3260 smtp_notquit_reason = reason;
3261 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3262 &log_msg)) == ERROR)
3263 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3267 /* Write an SMTP response if we are expected to give one. As the default
3268 responses are all internal, they should always fit in the buffer, but code a
3269 warning, just in case. Note that string_vformat() still leaves a complete
3270 string, even if it is incomplete. */
3272 if (code && defaultrespond)
3275 smtp_respond(code, 3, TRUE, user_msg);
3280 va_start(ap, defaultrespond);
3281 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3282 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3283 smtp_printf("%s %s\r\n", code, buffer);
3293 /*************************************************
3294 * Verify HELO argument *
3295 *************************************************/
3297 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3298 matched. It is also called from ACL processing if verify = helo is used and
3299 verification was not previously tried (i.e. helo_try_verify_hosts was not
3300 matched). The result of its processing is to set helo_verified and
3301 helo_verify_failed. These variables should both be FALSE for this function to
3304 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3305 for IPv6 ::ffff: literals.
3308 Returns: TRUE if testing was completed;
3309 FALSE on a temporary failure
3313 smtp_verify_helo(void)
3317 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3320 if (sender_helo_name == NULL)
3322 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3325 /* Deal with the case of -bs without an IP address */
3327 else if (sender_host_address == NULL)
3329 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3330 helo_verified = TRUE;
3333 /* Deal with the more common case when there is a sending IP address */
3335 else if (sender_helo_name[0] == '[')
3337 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3338 Ustrlen(sender_host_address)) == 0;
3343 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3344 helo_verified = Ustrncmp(sender_helo_name + 1,
3345 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3350 { if (helo_verified) debug_printf("matched host address\n"); }
3353 /* Do a reverse lookup if one hasn't already given a positive or negative
3354 response. If that fails, or the name doesn't match, try checking with a forward
3359 if (sender_host_name == NULL && !host_lookup_failed)
3360 yield = host_name_lookup() != DEFER;
3362 /* If a host name is known, check it and all its aliases. */
3364 if (sender_host_name)
3365 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3367 sender_helo_dnssec = sender_host_dnssec;
3368 HDEBUG(D_receive) debug_printf("matched host name\n");
3372 uschar **aliases = sender_host_aliases;
3374 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3376 sender_helo_dnssec = sender_host_dnssec;
3380 HDEBUG(D_receive) if (helo_verified)
3381 debug_printf("matched alias %s\n", *(--aliases));
3384 /* Final attempt: try a forward lookup of the helo name */
3393 h.name = sender_helo_name;
3400 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3402 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3403 NULL, NULL, NULL, &d, NULL, NULL);
3404 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3405 for (hh = &h; hh; hh = hh->next)
3406 if (Ustrcmp(hh->address, sender_host_address) == 0)
3408 helo_verified = TRUE;
3409 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3412 debug_printf("IP address for %s matches calling address\n"
3413 "Forward DNS security status: %sverified\n",
3414 sender_helo_name, sender_helo_dnssec ? "" : "un");
3421 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3428 /*************************************************
3429 * Send user response message *
3430 *************************************************/
3432 /* This function is passed a default response code and a user message. It calls
3433 smtp_message_code() to check and possibly modify the response code, and then
3434 calls smtp_respond() to transmit the response. I put this into a function
3435 just to avoid a lot of repetition.
3438 code the response code
3439 user_msg the user message
3445 smtp_user_msg(uschar *code, uschar *user_msg)
3448 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3449 smtp_respond(code, len, TRUE, user_msg);
3455 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3457 const uschar *set_id = NULL;
3460 /* Run the checking code, passing the remainder of the command line as
3461 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3462 it as the only set numerical variable. The authenticator may set $auth<n>
3463 and also set other numeric variables. The $auth<n> variables are preferred
3464 nowadays; the numerical variables remain for backwards compatibility.
3466 Afterwards, have a go at expanding the set_id string, even if
3467 authentication failed - for bad passwords it can be useful to log the
3468 userid. On success, require set_id to expand and exist, and put it in
3469 authenticated_id. Save this in permanent store, as the working store gets
3470 reset at HELO, RSET, etc. */
3472 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3474 expand_nlength[0] = 0; /* $0 contains nothing */
3476 rc = (au->info->servercode)(au, smtp_cmd_data);
3477 if (au->set_id) set_id = expand_string(au->set_id);
3478 expand_nmax = -1; /* Reset numeric variables */
3479 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3481 /* The value of authenticated_id is stored in the spool file and printed in
3482 log lines. It must not contain binary zeros or newline characters. In
3483 normal use, it never will, but when playing around or testing, this error
3484 can (did) happen. To guard against this, ensure that the id contains only
3485 printing characters. */
3487 if (set_id) set_id = string_printing(set_id);
3489 /* For the non-OK cases, set up additional logging data if set_id
3493 set_id = set_id && *set_id
3494 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3496 /* Switch on the result */
3501 if (!au->set_id || set_id) /* Complete success */
3503 if (set_id) authenticated_id = string_copy_malloc(set_id);
3504 sender_host_authenticated = au->name;
3505 authentication_failed = FALSE;
3506 authenticated_fail_id = NULL; /* Impossible to already be set? */
3509 (sender_host_address ? protocols : protocols_local)
3510 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3511 *s = *ss = US"235 Authentication succeeded";
3512 authenticated_by = au;
3516 /* Authentication succeeded, but we failed to expand the set_id string.
3517 Treat this as a temporary error. */
3519 auth_defer_msg = expand_string_message;
3523 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3524 *s = string_sprintf("435 Unable to authenticate at present%s",
3525 auth_defer_user_msg);
3526 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3527 set_id, auth_defer_msg);
3531 *s = *ss = US"501 Invalid base64 data";
3535 *s = *ss = US"501 Authentication cancelled";
3539 *s = *ss = US"553 Initial data not expected";
3543 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3544 *s = US"535 Incorrect authentication data";
3545 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3549 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3550 *s = US"435 Internal error";
3551 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3552 "check", set_id, rc);
3564 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3567 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3569 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3571 rd = Ustrlen(recipient) + 1;
3572 *recipient = rewrite_address_qualify(*recipient, TRUE);
3575 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3577 log_write(L_smtp_syntax_error,
3578 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3579 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3587 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3590 incomplete_transaction_log(US"QUIT");
3593 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3595 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3599 smtp_respond(US"221", 3, TRUE, *user_msgp);
3601 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3604 tls_close(TRUE, TRUE);
3607 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3608 smtp_get_connection_info());
3613 smtp_rset_handler(void)
3616 incomplete_transaction_log(US"RSET");
3617 smtp_printf("250 Reset OK\r\n");
3618 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3623 /*************************************************
3624 * Initialize for SMTP incoming message *
3625 *************************************************/
3627 /* This function conducts the initial dialogue at the start of an incoming SMTP
3628 message, and builds a list of recipients. However, if the incoming message
3629 is part of a batch (-bS option) a separate function is called since it would
3630 be messy having tests splattered about all over this function. This function
3631 therefore handles the case where interaction is occurring. The input and output
3632 files are set up in smtp_in and smtp_out.
3634 The global recipients_list is set to point to a vector of recipient_item
3635 blocks, whose number is given by recipients_count. This is extended by the
3636 receive_add_recipient() function. The global variable sender_address is set to
3637 the sender's address. The yield is +1 if a message has been successfully
3638 started, 0 if a QUIT command was encountered or the connection was refused from
3639 the particular host, or -1 if the connection was lost.
3643 Returns: > 0 message successfully started (reached DATA)
3644 = 0 QUIT read or end of file reached or call refused
3649 smtp_setup_msg(void)
3652 BOOL toomany = FALSE;
3653 BOOL discarded = FALSE;
3654 BOOL last_was_rej_mail = FALSE;
3655 BOOL last_was_rcpt = FALSE;
3656 void *reset_point = store_get(0);
3658 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3660 /* Reset for start of new message. We allow one RSET not to be counted as a
3661 nonmail command, for those MTAs that insist on sending it between every
3662 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3663 TLS between messages (an Exim client may do this if it has messages queued up
3664 for the host). Note: we do NOT reset AUTH at this point. */
3666 smtp_reset(reset_point);
3667 message_ended = END_NOTSTARTED;
3669 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3671 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3672 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3673 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3675 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3676 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3679 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3681 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3683 /* Batched SMTP is handled in a different function. */
3685 if (smtp_batched_input) return smtp_setup_batch_msg();
3687 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3688 value. The values are 2 larger than the required yield of the function. */
3692 const uschar **argv;
3693 uschar *etrn_command;
3694 uschar *etrn_serialize_key;
3696 uschar *log_msg, *smtp_code;
3697 uschar *user_msg = NULL;
3698 uschar *recipient = NULL;
3699 uschar *hello = NULL;
3701 BOOL was_rej_mail = FALSE;
3702 BOOL was_rcpt = FALSE;
3703 void (*oldsignal)(int);
3705 int start, end, sender_domain, recipient_domain;
3709 uschar *orcpt = NULL;
3713 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3714 if ( tls_in.active >= 0
3716 && tls_in.certificate_verified
3717 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3720 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3722 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3723 &user_msg, &log_msg)) != OK
3726 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3730 for (au = auths; au; au = au->next)
3731 if (strcmpic(US"tls", au->driver_name) == 0)
3733 smtp_cmd_data = NULL;
3735 if (smtp_in_auth(au, &s, &ss) == OK)
3736 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3738 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3745 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3746 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3747 US &off, sizeof(off));
3750 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3752 /* The AUTH command is not permitted to occur inside a transaction, and may
3753 occur successfully only once per connection. Actually, that isn't quite
3754 true. When TLS is started, all previous information about a connection must
3755 be discarded, so a new AUTH is permitted at that time.
3757 AUTH may only be used when it has been advertised. However, it seems that
3758 there are clients that send AUTH when it hasn't been advertised, some of
3759 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3760 So there's a get-out that allows this to happen.
3762 AUTH is initially labelled as a "nonmail command" so that one occurrence
3763 doesn't get counted. We change the label here so that multiple failing
3764 AUTHS will eventually hit the nonmail threshold. */
3768 authentication_failed = TRUE;
3769 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3771 if (!auth_advertised && !allow_auth_unadvertised)
3773 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3774 US"AUTH command used when not advertised");
3777 if (sender_host_authenticated)
3779 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3780 US"already authenticated");
3785 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3786 US"not permitted in mail transaction");
3793 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3794 &user_msg, &log_msg)) != OK
3797 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3801 /* Find the name of the requested authentication mechanism. */
3804 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3806 if (!isalnum(c) && c != '-' && c != '_')
3808 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3809 US"invalid character in authentication mechanism name");
3815 /* If not at the end of the line, we must be at white space. Terminate the
3816 name and move the pointer on to any data that may be present. */
3818 if (*smtp_cmd_data != 0)
3820 *smtp_cmd_data++ = 0;
3821 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3824 /* Search for an authentication mechanism which is configured for use
3825 as a server and which has been advertised (unless, sigh, allow_auth_
3826 unadvertised is set). */
3828 for (au = auths; au; au = au->next)
3829 if (strcmpic(s, au->public_name) == 0 && au->server &&
3830 (au->advertised || allow_auth_unadvertised))
3835 c = smtp_in_auth(au, &s, &ss);
3837 smtp_printf("%s\r\n", s);
3839 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3840 au->name, host_and_ident(FALSE), ss);
3843 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3844 string_sprintf("%s authentication mechanism not supported", s));
3846 break; /* AUTH_CMD */
3848 /* The HELO/EHLO commands are permitted to appear in the middle of a
3849 session as well as at the beginning. They have the effect of a reset in
3850 addition to their other functions. Their absence at the start cannot be
3851 taken to be an error.
3855 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3856 or 502 failure replies MUST be returned as appropriate. The SMTP
3857 server MUST stay in the same state after transmitting these replies
3858 that it was in before the EHLO was received.
3860 Therefore, we do not do the reset until after checking the command for
3861 acceptability. This change was made for Exim release 4.11. Previously
3862 it did the reset first. */
3875 HELO_EHLO: /* Common code for HELO and EHLO */
3876 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3877 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3879 /* Reject the HELO if its argument was invalid or non-existent. A
3880 successful check causes the argument to be saved in malloc store. */
3882 if (!check_helo(smtp_cmd_data))
3884 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3886 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3887 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3888 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3889 string_printing(smtp_cmd_argument));
3891 if (++synprot_error_count > smtp_max_synprot_errors)
3893 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3894 "syntax or protocol errors (last command was \"%s\")",
3895 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3902 /* If sender_host_unknown is true, we have got here via the -bs interface,
3903 not called from inetd. Otherwise, we are running an IP connection and the
3904 host address will be set. If the helo name is the primary name of this
3905 host and we haven't done a reverse lookup, force one now. If helo_required
3906 is set, ensure that the HELO name matches the actual host. If helo_verify
3907 is set, do the same check, but softly. */
3909 if (!sender_host_unknown)
3911 BOOL old_helo_verified = helo_verified;
3912 uschar *p = smtp_cmd_data;
3914 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3917 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3918 because otherwise the log can be confusing. */
3920 if (sender_host_name == NULL &&
3921 (deliver_domain = sender_helo_name, /* set $domain */
3922 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3923 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3924 (void)host_name_lookup();
3926 /* Rebuild the fullhost info to include the HELO name (and the real name
3927 if it was looked up.) */
3929 host_build_sender_fullhost(); /* Rebuild */
3930 set_process_info("handling%s incoming connection from %s",
3931 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3933 /* Verify if configured. This doesn't give much security, but it does
3934 make some people happy to be able to do it. If helo_required is set,
3935 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3936 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3937 now obsolescent, since the verification can now be requested selectively
3940 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3941 if (helo_required || helo_verify)
3943 BOOL tempfail = !smtp_verify_helo();
3948 smtp_printf("%d %s argument does not match calling host\r\n",
3949 tempfail? 451 : 550, hello);
3950 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3951 tempfail? "temporarily " : "",
3952 hello, sender_helo_name, host_and_ident(FALSE));
3953 helo_verified = old_helo_verified;
3954 break; /* End of HELO/EHLO processing */
3956 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3957 "helo_try_verify_hosts\n", hello);
3962 #ifdef EXPERIMENTAL_SPF
3963 /* set up SPF context */
3964 spf_init(sender_helo_name, sender_host_address);
3967 /* Apply an ACL check if one is defined; afterwards, recheck
3968 synchronization in case the client started sending in a delay. */
3971 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3972 &user_msg, &log_msg)) != OK)
3974 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3975 sender_helo_name = NULL;
3976 host_build_sender_fullhost(); /* Rebuild */
3979 else if (!check_sync()) goto SYNC_FAILURE;
3981 /* Generate an OK reply. The default string includes the ident if present,
3982 and also the IP address if present. Reflecting back the ident is intended
3983 as a deterrent to mail forgers. For maximum efficiency, and also because
3984 some broken systems expect each response to be in a single packet, arrange
3985 that the entire reply is sent in one write(). */
3987 auth_advertised = FALSE;
3988 pipelining_advertised = FALSE;
3990 tls_advertised = FALSE;
3992 dsn_advertised = FALSE;
3994 smtputf8_advertised = FALSE;
3997 smtp_code = US"250 "; /* Default response code plus space*/
3998 if (user_msg == NULL)
4000 s = string_sprintf("%.3s %s Hello %s%s%s",
4002 smtp_active_hostname,
4003 (sender_ident == NULL)? US"" : sender_ident,
4004 (sender_ident == NULL)? US"" : US" at ",
4005 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
4010 if (sender_host_address != NULL)
4012 s = string_catn(s, &size, &ptr, US" [", 2);
4013 s = string_cat (s, &size, &ptr, sender_host_address);
4014 s = string_catn(s, &size, &ptr, US"]", 1);
4018 /* A user-supplied EHLO greeting may not contain more than one line. Note
4019 that the code returned by smtp_message_code() includes the terminating
4020 whitespace character. */
4026 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4027 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4028 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4030 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4031 "newlines: message truncated: %s", string_printing(s));
4038 s = string_catn(s, &size, &ptr, US"\r\n", 2);
4040 /* If we received EHLO, we must create a multiline response which includes
4041 the functions supported. */
4047 /* I'm not entirely happy with this, as an MTA is supposed to check
4048 that it has enough room to accept a message of maximum size before
4049 it sends this. However, there seems little point in not sending it.
4050 The actual size check happens later at MAIL FROM time. By postponing it
4051 till then, VRFY and EXPN can be used after EHLO when space is short. */
4053 if (thismessage_size_limit > 0)
4055 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4056 thismessage_size_limit);
4057 s = string_cat(s, &size, &ptr, big_buffer);
4061 s = string_catn(s, &size, &ptr, smtp_code, 3);
4062 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
4065 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4066 clean; if it has an 8-bit character in its hand, it just sends it. It
4067 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4068 However, some users want this option simply in order to stop MUAs
4069 mangling messages that contain top-bit-set characters. It is therefore
4070 provided as an option. */
4072 if (accept_8bitmime)
4074 s = string_catn(s, &size, &ptr, smtp_code, 3);
4075 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
4078 /* Advertise DSN support if configured to do so. */
4079 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4081 s = string_catn(s, &size, &ptr, smtp_code, 3);
4082 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
4083 dsn_advertised = TRUE;
4086 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4087 permitted to issue them; a check is made when any host actually tries. */
4091 s = string_catn(s, &size, &ptr, smtp_code, 3);
4092 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
4096 s = string_catn(s, &size, &ptr, smtp_code, 3);
4097 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
4101 s = string_catn(s, &size, &ptr, smtp_code, 3);
4102 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
4105 /* Exim is quite happy with pipelining, so let the other end know that
4106 it is safe to use it, unless advertising is disabled. */
4108 if (pipelining_enable &&
4109 verify_check_host(&pipelining_advertise_hosts) == OK)
4111 s = string_catn(s, &size, &ptr, smtp_code, 3);
4112 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
4113 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4114 pipelining_advertised = TRUE;
4118 /* If any server authentication mechanisms are configured, advertise
4119 them if the current host is in auth_advertise_hosts. The problem with
4120 advertising always is that some clients then require users to
4121 authenticate (and aren't configurable otherwise) even though it may not
4122 be necessary (e.g. if the host is in host_accept_relay).
4124 RFC 2222 states that SASL mechanism names contain only upper case
4125 letters, so output the names in upper case, though we actually recognize
4126 them in either case in the AUTH command. */
4130 && !sender_host_authenticated
4132 && verify_check_host(&auth_advertise_hosts) == OK
4137 for (au = auths; au; au = au->next)
4138 if (au->server && (au->advertise_condition == NULL ||
4139 expand_check_condition(au->advertise_condition, au->name,
4140 US"authenticator")))
4145 s = string_catn(s, &size, &ptr, smtp_code, 3);
4146 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
4148 auth_advertised = TRUE;
4151 s = string_catn(s, &size, &ptr, US" ", 1);
4152 s = string_cat (s, &size, &ptr, au->public_name);
4153 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
4154 au->advertised = TRUE;
4157 au->advertised = FALSE;
4159 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4162 /* RFC 3030 CHUNKING */
4164 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4166 s = string_catn(s, &size, &ptr, smtp_code, 3);
4167 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4168 chunking_offered = TRUE;
4169 chunking_state = CHUNKING_OFFERED;
4172 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4173 if it has been included in the binary, and the host matches
4174 tls_advertise_hosts. We must *not* advertise if we are already in a
4175 secure connection. */
4178 if (tls_in.active < 0 &&
4179 verify_check_host(&tls_advertise_hosts) != FAIL)
4181 s = string_catn(s, &size, &ptr, smtp_code, 3);
4182 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4183 tls_advertised = TRUE;
4187 #ifndef DISABLE_PRDR
4188 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4191 s = string_catn(s, &size, &ptr, smtp_code, 3);
4192 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4197 if ( accept_8bitmime
4198 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4200 s = string_catn(s, &size, &ptr, smtp_code, 3);
4201 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4202 smtputf8_advertised = TRUE;
4206 /* Finish off the multiline reply with one that is always available. */
4208 s = string_catn(s, &size, &ptr, smtp_code, 3);
4209 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4212 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4218 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4222 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4227 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4228 memmove(cr, cr + 1, (ptr--) - (cr - s));
4229 debug_printf("SMTP>> %s", s);
4233 /* Reset the protocol and the state, abandoning any previous message. */
4235 (sender_host_address ? protocols : protocols_local)
4237 ? pextend + (sender_host_authenticated ? pauthed : 0)
4239 + (tls_in.active >= 0 ? pcrpted : 0)
4241 smtp_reset(reset_point);
4243 break; /* HELO/EHLO */
4246 /* The MAIL command requires an address as an operand. All we do
4247 here is to parse it for syntactic correctness. The form "<>" is
4248 a special case which converts into an empty string. The start/end
4249 pointers in the original are not used further for this address, as
4250 it is the canonical extracted address which is all that is kept. */
4254 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4255 was_rej_mail = TRUE; /* Reset if accepted */
4256 env_mail_type_t * mail_args; /* Sanity check & validate args */
4258 if (helo_required && !helo_seen)
4260 smtp_printf("503 HELO or EHLO required\r\n");
4261 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4262 "HELO/EHLO given", host_and_ident(FALSE));
4266 if (sender_address != NULL)
4268 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4269 US"sender already given");
4273 if (smtp_cmd_data[0] == 0)
4275 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4276 US"MAIL must have an address operand");
4280 /* Check to see if the limit for messages per connection would be
4281 exceeded by accepting further messages. */
4283 if (smtp_accept_max_per_connection > 0 &&
4284 smtp_mailcmd_count > smtp_accept_max_per_connection)
4286 smtp_printf("421 too many messages in this connection\r\n");
4287 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4288 "messages in one connection", host_and_ident(TRUE));
4292 /* Reset for start of message - even if this is going to fail, we
4293 obviously need to throw away any previous data. */
4295 smtp_reset(reset_point);
4297 sender_data = recipient_data = NULL;
4299 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4303 uschar *name, *value, *end;
4304 unsigned long int size;
4305 BOOL arg_error = FALSE;
4307 if (!extract_option(&name, &value)) break;
4309 for (mail_args = env_mail_type_list;
4310 mail_args->value != ENV_MAIL_OPT_NULL;
4313 if (strcmpic(name, mail_args->name) == 0)
4315 if (mail_args->need_value && strcmpic(value, US"") == 0)
4318 switch(mail_args->value)
4320 /* Handle SIZE= by reading the value. We don't do the check till later,
4321 in order to be able to log the sender address on failure. */
4322 case ENV_MAIL_OPT_SIZE:
4323 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4325 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4327 message_size = (int)size;
4333 /* If this session was initiated with EHLO and accept_8bitmime is set,
4334 Exim will have indicated that it supports the BODY=8BITMIME option. In
4335 fact, it does not support this according to the RFCs, in that it does not
4336 take any special action for forwarding messages containing 8-bit
4337 characters. That is why accept_8bitmime is not the default setting, but
4338 some sites want the action that is provided. We recognize both "8BITMIME"
4339 and "7BIT" as body types, but take no action. */
4340 case ENV_MAIL_OPT_BODY:
4341 if (accept_8bitmime) {
4342 if (strcmpic(value, US"8BITMIME") == 0)
4344 else if (strcmpic(value, US"7BIT") == 0)
4349 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4350 US"invalid data for BODY");
4353 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4359 /* Handle the two DSN options, but only if configured to do so (which
4360 will have caused "DSN" to be given in the EHLO response). The code itself
4361 is included only if configured in at build time. */
4363 case ENV_MAIL_OPT_RET:
4366 /* Check if RET has already been set */
4369 synprot_error(L_smtp_syntax_error, 501, NULL,
4370 US"RET can be specified once only");
4373 dsn_ret = strcmpic(value, US"HDRS") == 0
4375 : strcmpic(value, US"FULL") == 0
4378 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4379 /* Check for invalid invalid value, and exit with error */
4382 synprot_error(L_smtp_syntax_error, 501, NULL,
4383 US"Value for RET is invalid");
4388 case ENV_MAIL_OPT_ENVID:
4391 /* Check if the dsn envid has been already set */
4392 if (dsn_envid != NULL)
4394 synprot_error(L_smtp_syntax_error, 501, NULL,
4395 US"ENVID can be specified once only");
4398 dsn_envid = string_copy(value);
4399 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4403 /* Handle the AUTH extension. If the value given is not "<>" and either
4404 the ACL says "yes" or there is no ACL but the sending host is
4405 authenticated, we set it up as the authenticated sender. However, if the
4406 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4407 the condition is met. The value of AUTH is an xtext, which means that +,
4408 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4410 case ENV_MAIL_OPT_AUTH:
4411 if (Ustrcmp(value, "<>") != 0)
4416 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4418 /* Put back terminator overrides for error message */
4421 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4422 US"invalid data for AUTH");
4425 if (acl_smtp_mailauth == NULL)
4427 ignore_msg = US"client not authenticated";
4428 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4432 ignore_msg = US"rejected by ACL";
4433 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4434 &user_msg, &log_msg);
4440 if (authenticated_by == NULL ||
4441 authenticated_by->mail_auth_condition == NULL ||
4442 expand_check_condition(authenticated_by->mail_auth_condition,
4443 authenticated_by->name, US"authenticator"))
4444 break; /* Accept the AUTH */
4446 ignore_msg = US"server_mail_auth_condition failed";
4447 if (authenticated_id != NULL)
4448 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4449 ignore_msg, authenticated_id);
4454 authenticated_sender = NULL;
4455 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4456 value, host_and_ident(TRUE), ignore_msg);
4459 /* Should only get DEFER or ERROR here. Put back terminator
4460 overrides for error message */
4465 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4472 #ifndef DISABLE_PRDR
4473 case ENV_MAIL_OPT_PRDR:
4475 prdr_requested = TRUE;
4480 case ENV_MAIL_OPT_UTF8:
4481 if (smtputf8_advertised)
4483 int old_pool = store_pool;
4485 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4486 message_smtputf8 = allow_utf8_domains = TRUE;
4487 store_pool = POOL_PERM;
4488 received_protocol = string_sprintf("utf8%s", received_protocol);
4489 store_pool = old_pool;
4493 /* No valid option. Stick back the terminator characters and break
4494 the loop. Do the name-terminator second as extract_option sets
4495 value==name when it found no equal-sign.
4496 An error for a malformed address will occur. */
4497 case ENV_MAIL_OPT_NULL:
4505 /* Break out of for loop if switch() had bad argument or
4506 when start of the email address is reached */
4507 if (arg_error) break;
4510 /* If we have passed the threshold for rate limiting, apply the current
4511 delay, and update it for next time, provided this is a limited host. */
4513 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4514 verify_check_host(&smtp_ratelimit_hosts) == OK)
4516 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4517 smtp_delay_mail/1000.0);
4518 millisleep((int)smtp_delay_mail);
4519 smtp_delay_mail *= smtp_rlm_factor;
4520 if (smtp_delay_mail > (double)smtp_rlm_limit)
4521 smtp_delay_mail = (double)smtp_rlm_limit;
4524 /* Now extract the address, first applying any SMTP-time rewriting. The
4525 TRUE flag allows "<>" as a sender address. */
4527 raw_sender = rewrite_existflags & rewrite_smtp
4528 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4529 global_rewrite_rules)
4533 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4538 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4542 sender_address = raw_sender;
4544 /* If there is a configured size limit for mail, check that this message
4545 doesn't exceed it. The check is postponed to this point so that the sender
4548 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4550 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4551 log_write(L_size_reject,
4552 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4553 "message too big: size%s=%d max=%d",
4555 host_and_ident(TRUE),
4556 (message_size == INT_MAX)? ">" : "",
4558 thismessage_size_limit);
4559 sender_address = NULL;
4563 /* Check there is enough space on the disk unless configured not to.
4564 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4565 plus the current message - i.e. we accept the message only if it won't
4566 reduce the space below the threshold. Add 5000 to the size to allow for
4567 overheads such as the Received: line and storing of recipients, etc.
4568 By putting the check here, even when SIZE is not given, it allow VRFY
4569 and EXPN etc. to be used when space is short. */
4571 if (!receive_check_fs(
4572 (smtp_check_spool_space && message_size >= 0)?
4573 message_size + 5000 : 0))
4575 smtp_printf("452 Space shortage, please try later\r\n");
4576 sender_address = NULL;
4580 /* If sender_address is unqualified, reject it, unless this is a locally
4581 generated message, or the sending host or net is permitted to send
4582 unqualified addresses - typically local machines behaving as MUAs -
4583 in which case just qualify the address. The flag is set above at the start
4584 of the SMTP connection. */
4586 if (sender_domain == 0 && sender_address[0] != 0)
4588 if (allow_unqualified_sender)
4590 sender_domain = Ustrlen(sender_address) + 1;
4591 sender_address = rewrite_address_qualify(sender_address, FALSE);
4592 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4597 smtp_printf("501 %s: sender address must contain a domain\r\n",
4599 log_write(L_smtp_syntax_error,
4600 LOG_MAIN|LOG_REJECT,
4601 "unqualified sender rejected: <%s> %s%s",
4603 host_and_ident(TRUE),
4605 sender_address = NULL;
4610 /* Apply an ACL check if one is defined, before responding. Afterwards,
4611 when pipelining is not advertised, do another sync check in case the ACL
4612 delayed and the client started sending in the meantime. */
4616 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4617 if (rc == OK && !pipelining_advertised && !check_sync())
4623 if (rc == OK || rc == DISCARD)
4626 smtp_printf("%s%s%s", US"250 OK",
4627 #ifndef DISABLE_PRDR
4628 prdr_requested ? US", PRDR Requested" : US"",
4635 #ifndef DISABLE_PRDR
4637 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4639 smtp_user_msg(US"250", user_msg);
4641 smtp_delay_rcpt = smtp_rlr_base;
4642 recipients_discarded = (rc == DISCARD);
4643 was_rej_mail = FALSE;
4647 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4648 sender_address = NULL;
4653 /* The RCPT command requires an address as an operand. There may be any
4654 number of RCPT commands, specifying multiple recipients. We build them all
4655 into a data structure. The start/end values given by parse_extract_address
4656 are not used, as we keep only the extracted address. */
4661 was_rcpt = rcpt_in_progress = TRUE;
4663 /* There must be a sender address; if the sender was rejected and
4664 pipelining was advertised, we assume the client was pipelining, and do not
4665 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4666 get the same treatment. */
4668 if (sender_address == NULL)
4670 if (pipelining_advertised && last_was_rej_mail)
4672 smtp_printf("503 sender not yet given\r\n");
4673 was_rej_mail = TRUE;
4677 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4678 US"sender not yet given");
4679 was_rcpt = FALSE; /* Not a valid RCPT */
4685 /* Check for an operand */
4687 if (smtp_cmd_data[0] == 0)
4689 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4690 US"RCPT must have an address operand");
4695 /* Set the DSN flags orcpt and dsn_flags from the session*/
4701 uschar *name, *value;
4703 if (!extract_option(&name, &value))
4706 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4708 /* Check whether orcpt has been already set */
4711 synprot_error(L_smtp_syntax_error, 501, NULL,
4712 US"ORCPT can be specified once only");
4715 orcpt = string_copy(value);
4716 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4719 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4721 /* Check if the notify flags have been already set */
4724 synprot_error(L_smtp_syntax_error, 501, NULL,
4725 US"NOTIFY can be specified once only");
4728 if (strcmpic(value, US"NEVER") == 0)
4729 flags |= rf_notify_never;
4736 while (*pp != 0 && *pp != ',') pp++;
4737 if (*pp == ',') *pp++ = 0;
4738 if (strcmpic(p, US"SUCCESS") == 0)
4740 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4741 flags |= rf_notify_success;
4743 else if (strcmpic(p, US"FAILURE") == 0)
4745 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4746 flags |= rf_notify_failure;
4748 else if (strcmpic(p, US"DELAY") == 0)
4750 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4751 flags |= rf_notify_delay;
4755 /* Catch any strange values */
4756 synprot_error(L_smtp_syntax_error, 501, NULL,
4757 US"Invalid value for NOTIFY parameter");
4762 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4766 /* Unknown option. Stick back the terminator characters and break
4767 the loop. An error for a malformed address will occur. */
4771 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4778 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4779 as a recipient address */
4781 recipient = rewrite_existflags & rewrite_smtp
4782 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4783 global_rewrite_rules)
4786 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4787 &recipient_domain, FALSE)))
4789 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4794 /* If the recipient address is unqualified, reject it, unless this is a
4795 locally generated message. However, unqualified addresses are permitted
4796 from a configured list of hosts and nets - typically when behaving as
4797 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4798 really. The flag is set at the start of the SMTP connection.
4800 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4801 assumed this meant "reserved local part", but the revision of RFC 821 and
4802 friends now makes it absolutely clear that it means *mailbox*. Consequently
4803 we must always qualify this address, regardless. */
4805 if (!recipient_domain)
4806 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4813 /* Check maximum allowed */
4815 if (rcpt_count > recipients_max && recipients_max > 0)
4817 if (recipients_max_reject)
4820 smtp_printf("552 too many recipients\r\n");
4822 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4823 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4828 smtp_printf("452 too many recipients\r\n");
4830 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4831 "temporarily rejected: sender=<%s> %s", sender_address,
4832 host_and_ident(TRUE));
4839 /* If we have passed the threshold for rate limiting, apply the current
4840 delay, and update it for next time, provided this is a limited host. */
4842 if (rcpt_count > smtp_rlr_threshold &&
4843 verify_check_host(&smtp_ratelimit_hosts) == OK)
4845 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4846 smtp_delay_rcpt/1000.0);
4847 millisleep((int)smtp_delay_rcpt);
4848 smtp_delay_rcpt *= smtp_rlr_factor;
4849 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4850 smtp_delay_rcpt = (double)smtp_rlr_limit;
4853 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4854 for them. Otherwise, check the access control list for this recipient. As
4855 there may be a delay in this, re-check for a synchronization error
4856 afterwards, unless pipelining was advertised. */
4858 if (recipients_discarded)
4861 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4863 && !pipelining_advertised && !check_sync())
4866 /* The ACL was happy */
4871 smtp_user_msg(US"250", user_msg);
4873 smtp_printf("250 Accepted\r\n");
4874 receive_add_recipient(recipient, -1);
4876 /* Set the dsn flags in the recipients_list */
4877 recipients_list[recipients_count-1].orcpt = orcpt;
4878 recipients_list[recipients_count-1].dsn_flags = flags;
4880 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4881 recipients_list[recipients_count-1].orcpt,
4882 recipients_list[recipients_count-1].dsn_flags);
4885 /* The recipient was discarded */
4887 else if (rc == DISCARD)
4890 smtp_user_msg(US"250", user_msg);
4892 smtp_printf("250 Accepted\r\n");
4895 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4896 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4897 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4898 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4899 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4902 /* Either the ACL failed the address, or it was deferred. */
4906 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4907 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4912 /* The DATA command is legal only if it follows successful MAIL FROM
4913 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4914 not counted as a protocol error if it follows RCPT (which must have been
4915 rejected if there are no recipients.) This function is complete when a
4916 valid DATA command is encountered.
4918 Note concerning the code used: RFC 2821 says this:
4920 - If there was no MAIL, or no RCPT, command, or all such commands
4921 were rejected, the server MAY return a "command out of sequence"
4922 (503) or "no valid recipients" (554) reply in response to the
4925 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4926 because it is the same whether pipelining is in use or not.
4928 If all the RCPT commands that precede DATA provoked the same error message
4929 (often indicating some kind of system error), it is helpful to include it
4930 with the DATA rejection (an idea suggested by Tony Finch). */
4937 if (chunking_state != CHUNKING_OFFERED)
4939 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4940 US"BDAT command used when CHUNKING not advertised");
4944 /* grab size, endmarker */
4946 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
4948 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4949 US"missing size for BDAT command");
4952 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
4953 ? CHUNKING_LAST : CHUNKING_ACTIVE;
4954 chunking_data_left = chunking_datasize;
4955 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
4956 (int)chunking_state, chunking_data_left);
4958 lwr_receive_getc = receive_getc;
4959 lwr_receive_ungetc = receive_ungetc;
4960 receive_getc = bdat_getc;
4961 receive_ungetc = bdat_ungetc;
4969 DATA_BDAT: /* Common code for DATA and BDAT */
4970 if (!discarded && recipients_count <= 0)
4972 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4974 uschar *code = US"503";
4975 int len = Ustrlen(rcpt_smtp_response);
4976 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4978 /* Responses from smtp_printf() will have \r\n on the end */
4979 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4980 rcpt_smtp_response[len-2] = 0;
4981 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4983 if (pipelining_advertised && last_was_rcpt)
4984 smtp_printf("503 Valid RCPT command must precede %s\r\n",
4985 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
4987 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4988 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
4989 ? US"valid RCPT command must precede DATA"
4990 : US"valid RCPT command must precede BDAT");
4992 if (chunking_state > CHUNKING_OFFERED)
4997 if (toomany && recipients_max_reject)
4999 sender_address = NULL; /* This will allow a new MAIL without RSET */
5000 sender_address_unrewritten = NULL;
5001 smtp_printf("554 Too many recipients\r\n");
5005 if (chunking_state > CHUNKING_OFFERED)
5006 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5009 /* If there is an ACL, re-check the synchronization afterwards, since the
5010 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5011 to get the DATA command sent. */
5013 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5017 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5018 enable_dollar_recipients = TRUE;
5019 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5021 enable_dollar_recipients = FALSE;
5022 if (rc == OK && !check_sync())
5026 { /* Either the ACL failed the address, or it was deferred. */
5027 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5033 smtp_user_msg(US"354", user_msg);
5036 "354 Enter message, ending with \".\" on a line by itself\r\n");
5040 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5041 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5042 US &on, sizeof(on));
5045 message_ended = END_NOTENDED; /* Indicate in middle of data */
5056 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5057 &start, &end, &recipient_domain, FALSE)))
5059 smtp_printf("501 %s\r\n", errmess);
5063 if (!recipient_domain)
5064 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5068 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5069 &user_msg, &log_msg)) != OK)
5070 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5074 address_item * addr = deliver_make_addr(address, FALSE);
5076 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5077 -1, -1, NULL, NULL, NULL))
5080 s = string_sprintf("250 <%s> is deliverable", address);
5084 s = (addr->user_message != NULL)?
5085 string_sprintf("451 <%s> %s", address, addr->user_message) :
5086 string_sprintf("451 Cannot resolve <%s> at this time", address);
5090 s = (addr->user_message != NULL)?
5091 string_sprintf("550 <%s> %s", address, addr->user_message) :
5092 string_sprintf("550 <%s> is not deliverable", address);
5093 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5094 smtp_cmd_argument, host_and_ident(TRUE));
5098 smtp_printf("%s\r\n", s);
5106 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5108 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5111 BOOL save_log_testing_mode = log_testing_mode;
5112 address_test_mode = log_testing_mode = TRUE;
5113 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5114 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5116 address_test_mode = FALSE;
5117 log_testing_mode = save_log_testing_mode; /* true for -bh */
5126 if (!tls_advertised)
5128 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5129 US"STARTTLS command used when not advertised");
5133 /* Apply an ACL check if one is defined */
5135 if ( acl_smtp_starttls
5136 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5137 &user_msg, &log_msg)) != OK
5140 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5144 /* RFC 2487 is not clear on when this command may be sent, though it
5145 does state that all information previously obtained from the client
5146 must be discarded if a TLS session is started. It seems reasonable to
5147 do an implied RSET when STARTTLS is received. */
5149 incomplete_transaction_log(US"STARTTLS");
5150 smtp_reset(reset_point);
5152 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5154 /* There's an attack where more data is read in past the STARTTLS command
5155 before TLS is negotiated, then assumed to be part of the secure session
5156 when used afterwards; we use segregated input buffers, so are not
5157 vulnerable, but we want to note when it happens and, for sheer paranoia,
5158 ensure that the buffer is "wiped".
5159 Pipelining sync checks will normally have protected us too, unless disabled
5160 by configuration. */
5162 if (receive_smtp_buffered())
5165 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5166 if (tls_in.active < 0)
5167 smtp_inend = smtp_inptr = smtp_inbuffer;
5168 /* and if TLS is already active, tls_server_start() should fail */
5171 /* There is nothing we value in the input buffer and if TLS is successfully
5172 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5173 fresh content into it. The buffer contains arbitrary content from an
5174 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5175 It seems safest to just wipe away the content rather than leave it as a
5176 target to jump to. */
5178 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5180 /* Attempt to start up a TLS session, and if successful, discard all
5181 knowledge that was obtained previously. At least, that's what the RFC says,
5182 and that's what happens by default. However, in order to work round YAEB,
5183 there is an option to remember the esmtp state. Sigh.
5185 We must allow for an extra EHLO command and an extra AUTH command after
5186 STARTTLS that don't add to the nonmail command count. */
5188 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
5190 if (!tls_remember_esmtp)
5191 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5192 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5193 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5194 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5195 if (sender_helo_name != NULL)
5197 store_free(sender_helo_name);
5198 sender_helo_name = NULL;
5199 host_build_sender_fullhost(); /* Rebuild */
5200 set_process_info("handling incoming TLS connection from %s",
5201 host_and_ident(FALSE));
5204 (sender_host_address ? protocols : protocols_local)
5206 ? pextend + (sender_host_authenticated ? pauthed : 0)
5208 + (tls_in.active >= 0 ? pcrpted : 0)
5211 sender_host_authenticated = NULL;
5212 authenticated_id = NULL;
5213 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5214 DEBUG(D_tls) debug_printf("TLS active\n");
5215 break; /* Successful STARTTLS */
5218 /* Some local configuration problem was discovered before actually trying
5219 to do a TLS handshake; give a temporary error. */
5221 else if (rc == DEFER)
5223 smtp_printf("454 TLS currently unavailable\r\n");
5227 /* Hard failure. Reject everything except QUIT or closed connection. One
5228 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5229 set, but we must still reject all incoming commands. */
5231 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5232 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5235 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5236 smtp_get_connection_info());
5237 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5241 /* It is perhaps arguable as to which exit ACL should be called here,
5242 but as it is probably a situation that almost never arises, it
5243 probably doesn't matter. We choose to call the real QUIT ACL, which in
5244 some sense is perhaps "right". */
5249 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5250 &log_msg)) == ERROR))
5251 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5254 smtp_respond(US"221", 3, TRUE, user_msg);
5256 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
5257 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5258 smtp_get_connection_info());
5263 smtp_printf("554 Security failure\r\n");
5266 tls_close(TRUE, TRUE);
5271 /* The ACL for QUIT is provided for gathering statistical information or
5272 similar; it does not affect the response code, but it can supply a custom
5276 smtp_quit_handler(&user_msg, &log_msg);
5282 smtp_rset_handler();
5283 smtp_reset(reset_point);
5290 smtp_printf("250 OK\r\n");
5294 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5295 used, a check will be done for permitted hosts. Show STARTTLS only if not
5296 already in a TLS session and if it would be advertised in the EHLO
5301 smtp_printf("214-Commands supported:\r\n");
5305 Ustrcat(buffer, " AUTH");
5307 if (tls_in.active < 0 &&
5308 verify_check_host(&tls_advertise_hosts) != FAIL)
5309 Ustrcat(buffer, " STARTTLS");
5311 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5312 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5313 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5314 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5315 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5316 smtp_printf("214%s\r\n", buffer);
5322 incomplete_transaction_log(US"connection lost");
5323 smtp_notquit_exit(US"connection-lost", US"421",
5324 US"%s lost input connection", smtp_active_hostname);
5326 /* Don't log by default unless in the middle of a message, as some mailers
5327 just drop the call rather than sending QUIT, and it clutters up the logs.
5330 if (sender_address != NULL || recipients_count > 0)
5331 log_write(L_lost_incoming_connection,
5333 "unexpected %s while reading SMTP command from %s%s",
5334 sender_host_unknown? "EOF" : "disconnection",
5335 host_and_ident(FALSE), smtp_read_error);
5337 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5338 smtp_get_connection_info(), smtp_read_error);
5346 if (sender_address != NULL)
5348 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5349 US"ETRN is not permitted inside a transaction");
5353 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5354 host_and_ident(FALSE));
5356 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5357 &user_msg, &log_msg)) != OK)
5359 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5363 /* Compute the serialization key for this command. */
5365 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5367 /* If a command has been specified for running as a result of ETRN, we
5368 permit any argument to ETRN. If not, only the # standard form is permitted,
5369 since that is strictly the only kind of ETRN that can be implemented
5370 according to the RFC. */
5372 if (smtp_etrn_command != NULL)
5376 etrn_command = smtp_etrn_command;
5377 deliver_domain = smtp_cmd_data;
5378 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5379 US"ETRN processing", &error);
5380 deliver_domain = NULL;
5383 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5385 smtp_printf("458 Internal failure\r\n");
5390 /* Else set up to call Exim with the -R option. */
5394 if (*smtp_cmd_data++ != '#')
5396 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5397 US"argument must begin with #");
5400 etrn_command = US"exim -R";
5401 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5402 *queue_name ? 4 : 2,
5403 US"-R", smtp_cmd_data,
5404 US"-MCG", queue_name);
5407 /* If we are host-testing, don't actually do anything. */
5413 debug_printf("ETRN command is: %s\n", etrn_command);
5414 debug_printf("ETRN command execution skipped\n");
5416 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5417 else smtp_user_msg(US"250", user_msg);
5422 /* If ETRN queue runs are to be serialized, check the database to
5423 ensure one isn't already running. */
5425 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5427 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
5431 /* Fork a child process and run the command. We don't want to have to
5432 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5433 forking. It should be set that way anyway for external incoming SMTP,
5434 but we save and restore to be tidy. If serialization is required, we
5435 actually run the command in yet another process, so we can wait for it
5436 to complete and then remove the serialization lock. */
5438 oldsignal = signal(SIGCHLD, SIG_IGN);
5440 if ((pid = fork()) == 0)
5442 smtp_input = FALSE; /* This process is not associated with the */
5443 (void)fclose(smtp_in); /* SMTP call any more. */
5444 (void)fclose(smtp_out);
5446 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5448 /* If not serializing, do the exec right away. Otherwise, fork down
5449 into another process. */
5451 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5453 DEBUG(D_exec) debug_print_argv(argv);
5454 exim_nullstd(); /* Ensure std{in,out,err} exist */
5455 execv(CS argv[0], (char *const *)argv);
5456 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5457 etrn_command, strerror(errno));
5458 _exit(EXIT_FAILURE); /* paranoia */
5461 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5462 is, we are in the first subprocess, after forking again. All we can do
5463 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5464 complete, before removing the serialization. */
5467 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5468 "failed: %s", strerror(errno));
5472 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5474 (void)wait(&status);
5475 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5479 enq_end(etrn_serialize_key);
5480 _exit(EXIT_SUCCESS);
5483 /* Back in the top level SMTP process. Check that we started a subprocess
5484 and restore the signal state. */
5488 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5490 smtp_printf("458 Unable to fork process\r\n");
5491 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5495 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5496 else smtp_user_msg(US"250", user_msg);
5499 signal(SIGCHLD, oldsignal);
5504 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5505 US"unexpected argument data");
5509 /* This currently happens only for NULLs, but could be extended. */
5512 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5513 US"NULL character(s) present (shown as '?')");
5514 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5520 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5521 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5522 c = smtp_inend - smtp_inptr;
5523 if (c > 150) c = 150;
5525 incomplete_transaction_log(US"sync failure");
5526 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5527 "(next input sent too soon: pipelining was%s advertised): "
5528 "rejected \"%s\" %s next input=\"%s\"",
5529 pipelining_advertised? "" : " not",
5530 smtp_cmd_buffer, host_and_ident(TRUE),
5531 string_printing(smtp_inptr));
5532 smtp_notquit_exit(US"synchronization-error", US"554",
5533 US"SMTP synchronization error");
5534 done = 1; /* Pretend eof - drops connection */
5538 case TOO_MANY_NONMAIL_CMD:
5539 s = smtp_cmd_buffer;
5540 while (*s != 0 && !isspace(*s)) s++;
5541 incomplete_transaction_log(US"too many non-mail commands");
5542 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5543 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5544 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5545 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5546 done = 1; /* Pretend eof - drops connection */
5549 #ifdef SUPPORT_PROXY
5550 case PROXY_FAIL_IGNORE_CMD:
5551 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5556 if (unknown_command_count++ >= smtp_max_unknown_commands)
5558 log_write(L_smtp_syntax_error, LOG_MAIN,
5559 "SMTP syntax error in \"%s\" %s %s",
5560 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5561 US"unrecognized command");
5562 incomplete_transaction_log(US"unrecognized command");
5563 smtp_notquit_exit(US"bad-commands", US"500",
5564 US"Too many unrecognized commands");
5566 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5567 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5568 string_printing(smtp_cmd_buffer));
5571 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5572 US"unrecognized command");
5576 /* This label is used by goto's inside loops that want to break out to
5577 the end of the command-processing loop. */
5580 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5581 last_was_rcpt = was_rcpt; /* protocol error handling */
5585 return done - 2; /* Convert yield values */
5590 /* End of smtp_in.c */