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 int bdat_ungetc(int ch);
308 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
309 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
310 static void smtp_quit_handler(uschar **, uschar **);
311 static void smtp_rset_handler(void);
313 /*************************************************
314 * Recheck synchronization *
315 *************************************************/
317 /* Synchronization checks can never be perfect because a packet may be on its
318 way but not arrived when the check is done. Such checks can in any case only be
319 done when TLS is not in use. Normally, the checks happen when commands are
320 read: Exim ensures that there is no more input in the input buffer. In normal
321 cases, the response to the command will be fast, and there is no further check.
323 However, for some commands an ACL is run, and that can include delays. In those
324 cases, it is useful to do another check on the input just before sending the
325 response. This also applies at the start of a connection. This function does
326 that check by means of the select() function, as long as the facility is not
327 disabled or inappropriate. A failure of select() is ignored.
329 When there is unwanted input, we read it so that it appears in the log of the
333 Returns: TRUE if all is well; FALSE if there is input pending
341 struct timeval tzero;
343 if (!smtp_enforce_sync || sender_host_address == NULL ||
344 sender_host_notsocket || tls_in.active >= 0)
347 fd = fileno(smtp_in);
352 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
354 if (rc <= 0) return TRUE; /* Not ready to read */
355 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
356 if (rc < 0) return TRUE; /* End of file or error */
359 rc = smtp_inend - smtp_inptr;
360 if (rc > 150) rc = 150;
367 /*************************************************
368 * Log incomplete transactions *
369 *************************************************/
371 /* This function is called after a transaction has been aborted by RSET, QUIT,
372 connection drops or other errors. It logs the envelope information received
373 so far in order to preserve address verification attempts.
375 Argument: string to indicate what aborted the transaction
380 incomplete_transaction_log(uschar *what)
382 if (sender_address == NULL || /* No transaction in progress */
383 !LOGGING(smtp_incomplete_transaction))
386 /* Build list of recipients for logging */
388 if (recipients_count > 0)
391 raw_recipients = store_get(recipients_count * sizeof(uschar *));
392 for (i = 0; i < recipients_count; i++)
393 raw_recipients[i] = recipients_list[i].address;
394 raw_recipients_count = recipients_count;
397 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
398 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
404 /*************************************************
405 * SMTP version of getc() *
406 *************************************************/
408 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
409 it flushes the output, and refills the buffer, with a timeout. The signal
410 handler is set appropriately by the calling function. This function is not used
411 after a connection has negotiated itself into an TLS/SSL state.
413 Arguments: lim Maximum amount to read/buffer
414 Returns: the next character or EOF
418 smtp_getc(unsigned lim)
420 if (smtp_inptr >= smtp_inend)
423 if (!smtp_out) return EOF;
425 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
427 /* Limit amount read, so non-message data is not fed to DKIM */
429 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
434 /* Must put the error text in fixed store, because this might be during
435 header reading, where it releases unused store above the header. */
438 smtp_had_error = save_errno;
439 smtp_read_error = string_copy_malloc(
440 string_sprintf(" (error: %s)", strerror(save_errno)));
442 else smtp_had_eof = 1;
446 dkim_exim_verify_feed(smtp_inbuffer, rc);
448 smtp_inend = smtp_inbuffer + rc;
449 smtp_inptr = smtp_inbuffer;
451 return *smtp_inptr++;
458 int n = smtp_inend - smtp_inptr;
460 dkim_exim_verify_feed(smtp_inptr, n);
465 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
466 previous BDAT chunk and getting new ones when we run out. Uses the
467 underlying smtp_getc or tls_getc both for that and for getting the
468 (buffered) data byte. EOD signals (an expected) no further data.
469 ERR signals a protocol error, and EOF a closed input stream.
471 Called from read_bdat_smtp() in receive.c for the message body, but also
472 by the headers read loop in receive_msg(); manipulates chunking_state
473 to handle the BDAT command/response.
474 Placed here due to the correlation with the above smtp_getc(), which it wraps,
475 and also by the need to do smtp command/response handling.
477 Arguments: lim (ignored)
478 Returns: the next character or ERR, EOD or EOF
482 bdat_getc(unsigned lim)
484 uschar * user_msg = NULL;
489 if (chunking_data_left > 0)
490 return lwr_receive_getc(chunking_data_left--);
492 receive_getc = lwr_receive_getc;
493 receive_ungetc = lwr_receive_ungetc;
495 dkim_collect_input = FALSE;
498 /* Unless PIPELINING was offered, there should be no next command
499 until after we ack that chunk */
501 if (!pipelining_advertised && !check_sync())
503 incomplete_transaction_log(US"sync failure");
504 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
505 "(next input sent too soon: pipelining was not advertised): "
506 "rejected \"%s\" %s next input=\"%s\"",
507 smtp_cmd_buffer, host_and_ident(TRUE),
508 string_printing(smtp_inptr));
509 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
510 US"SMTP synchronization error");
511 goto repeat_until_rset;
514 /* If not the last, ack the received chunk. The last response is delayed
515 until after the data ACL decides on it */
517 if (chunking_state == CHUNKING_LAST)
520 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
525 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
526 chunking_state = CHUNKING_OFFERED;
527 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
529 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
530 QUIT, RSET or NOOP but handling them seems obvious */
533 switch(smtp_read_command(TRUE, 1))
536 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
537 US"only BDAT permissible after non-LAST BDAT");
540 switch(smtp_read_command(TRUE, 1))
542 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
543 case EOF_CMD: return EOF;
544 case RSET_CMD: smtp_rset_handler(); return ERR;
545 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
546 US"only RSET accepted now") > 0)
548 goto repeat_until_rset;
552 smtp_quit_handler(&user_msg, &log_msg);
563 smtp_printf("250 OK\r\n");
570 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
572 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
573 US"missing size for BDAT command");
576 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
577 ? CHUNKING_LAST : CHUNKING_ACTIVE;
578 chunking_data_left = chunking_datasize;
579 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
580 (int)chunking_state, chunking_data_left);
582 if (chunking_datasize == 0)
583 if (chunking_state == CHUNKING_LAST)
587 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
588 US"zero size for BDAT command");
589 goto repeat_until_rset;
592 receive_getc = bdat_getc;
593 receive_ungetc = bdat_ungetc;
595 dkim_collect_input = TRUE;
597 break; /* to top of main loop */
604 bdat_flush_data(void)
606 while (chunking_data_left > 0)
607 if (lwr_receive_getc(chunking_data_left--) < 0)
610 receive_getc = lwr_receive_getc;
611 receive_ungetc = lwr_receive_ungetc;
613 if (chunking_state != CHUNKING_LAST)
615 chunking_state = CHUNKING_OFFERED;
616 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
623 /*************************************************
624 * SMTP version of ungetc() *
625 *************************************************/
627 /* Puts a character back in the input buffer. Only ever
633 Returns: the character
647 chunking_data_left++;
648 return lwr_receive_ungetc(ch);
653 /*************************************************
654 * SMTP version of feof() *
655 *************************************************/
657 /* Tests for a previous EOF
660 Returns: non-zero if the eof flag is set
672 /*************************************************
673 * SMTP version of ferror() *
674 *************************************************/
676 /* Tests for a previous read error, and returns with errno
677 restored to what it was when the error was detected.
680 Returns: non-zero if the error flag is set
686 errno = smtp_had_error;
687 return smtp_had_error;
692 /*************************************************
693 * Test for characters in the SMTP buffer *
694 *************************************************/
696 /* Used at the end of a message
705 return smtp_inptr < smtp_inend;
710 /*************************************************
711 * Write formatted string to SMTP channel *
712 *************************************************/
714 /* This is a separate function so that we don't have to repeat everything for
715 TLS support or debugging. It is global so that the daemon and the
716 authentication functions can use it. It does not return any error indication,
717 because major problems such as dropped connections won't show up till an output
718 flush for non-TLS connections. The smtp_fflush() function is available for
719 checking that: for convenience, TLS output errors are remembered here so that
720 they are also picked up later by smtp_fflush().
724 ... optional arguments
730 smtp_printf(const char *format, ...)
734 va_start(ap, format);
735 smtp_vprintf(format, ap);
739 /* This is split off so that verify.c:respond_printf() can, in effect, call
740 smtp_printf(), bearing in mind that in C a vararg function can't directly
741 call another vararg function, only a function which accepts a va_list. */
744 smtp_vprintf(const char *format, va_list ap)
748 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
752 void *reset_point = store_get(0);
753 uschar *msg_copy, *cr, *end;
754 msg_copy = string_copy(big_buffer);
755 end = msg_copy + Ustrlen(msg_copy);
756 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
757 memmove(cr, cr + 1, (end--) - cr);
758 debug_printf("SMTP>> %s", msg_copy);
759 store_reset(reset_point);
764 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
765 smtp_closedown(US"Unexpected error");
766 exim_exit(EXIT_FAILURE);
769 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
770 have had the same. Note: this code is also present in smtp_respond(). It would
771 be tidier to have it only in one place, but when it was added, it was easier to
772 do it that way, so as not to have to mess with the code for the RCPT command,
773 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
775 if (rcpt_in_progress)
777 if (rcpt_smtp_response == NULL)
778 rcpt_smtp_response = string_copy(big_buffer);
779 else if (rcpt_smtp_response_same &&
780 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
781 rcpt_smtp_response_same = FALSE;
782 rcpt_in_progress = FALSE;
785 /* Now write the string */
788 if (tls_in.active >= 0)
790 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
791 smtp_write_error = -1;
796 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
801 /*************************************************
802 * Flush SMTP out and check for error *
803 *************************************************/
805 /* This function isn't currently used within Exim (it detects errors when it
806 tries to read the next SMTP input), but is available for use in local_scan().
807 For non-TLS connections, it flushes the output and checks for errors. For
808 TLS-connections, it checks for a previously-detected TLS write error.
811 Returns: 0 for no error; -1 after an error
817 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
818 return smtp_write_error;
823 /*************************************************
824 * SMTP command read timeout *
825 *************************************************/
827 /* Signal handler for timing out incoming SMTP commands. This attempts to
830 Argument: signal number (SIGALRM)
835 command_timeout_handler(int sig)
837 sig = sig; /* Keep picky compilers happy */
838 log_write(L_lost_incoming_connection,
839 LOG_MAIN, "SMTP command timeout on%s connection from %s",
840 (tls_in.active >= 0)? " TLS" : "",
841 host_and_ident(FALSE));
842 if (smtp_batched_input)
843 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
844 smtp_notquit_exit(US"command-timeout", US"421",
845 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
846 exim_exit(EXIT_FAILURE);
851 /*************************************************
853 *************************************************/
855 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
857 Argument: signal number (SIGTERM)
862 command_sigterm_handler(int sig)
864 sig = sig; /* Keep picky compilers happy */
865 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
866 if (smtp_batched_input)
867 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
868 smtp_notquit_exit(US"signal-exit", US"421",
869 US"%s: Service not available - closing connection", smtp_active_hostname);
870 exim_exit(EXIT_FAILURE);
877 /*************************************************
878 * Restore socket timeout to previous value *
879 *************************************************/
880 /* If the previous value was successfully retrieved, restore
881 it before returning control to the non-proxy routines
883 Arguments: fd - File descriptor for input
884 get_ok - Successfully retrieved previous values
885 tvtmp - Time struct with previous values
886 vslen - Length of time struct
890 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
893 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
896 /*************************************************
897 * Check if host is required proxy host *
898 *************************************************/
899 /* The function determines if inbound host will be a regular smtp host
900 or if it is configured that it must use Proxy Protocol. A local
908 check_proxy_protocol_host()
912 if ( sender_host_address
913 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
914 sender_host_address, NULL)) == OK)
917 debug_printf("Detected proxy protocol configured host\n");
918 proxy_session = TRUE;
920 return proxy_session;
924 /*************************************************
925 * Read data until newline or end of buffer *
926 *************************************************/
927 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
928 read an entire buffer and assume there will be nothing past a proxy protocol
929 header. Our approach normally is to use stdio, but again that relies upon
930 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
931 reading _nothing_ before client TLS handshake. So we don't want to use the
932 usual buffering reads which may read enough to block TLS starting.
934 So unfortunately we're down to "read one byte at a time, with a syscall each,
935 and expect a little overhead", for all proxy-opened connections which are v1,
936 just to handle the TLS-on-connect case. Since SSL functions wrap the
937 underlying fd, we can't assume that we can feed them any already-read content.
939 We need to know where to read to, the max capacity, and we'll read until we
940 get a CR and one more character. Let the caller scream if it's CR+!LF.
942 Return the amount read.
946 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
948 uschar *to = base + already;
954 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
955 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
956 cr = memchr(base, '\r', already);
959 if ((cr - base) < already - 1)
961 /* \r and presumed \n already within what we have; probably not
962 actually proxy protocol, but abort cleanly. */
965 /* \r is last character read, just need one more. */
971 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
982 // reached end without having room for a final newline, abort
987 /*************************************************
988 * Setup host for proxy protocol *
989 *************************************************/
990 /* The function configures the connection based on a header from the
991 inbound host to use Proxy Protocol. The specification is very exact
992 so exit with an error if do not find the exact required pieces. This
993 includes an incorrect number of spaces separating args.
996 Returns: Boolean success
1000 setup_proxy_protocol_host()
1012 struct { /* TCP/UDP over IPv4, len = 12 */
1018 struct { /* TCP/UDP over IPv6, len = 36 */
1019 uint8_t src_addr[16];
1020 uint8_t dst_addr[16];
1024 struct { /* AF_UNIX sockets, len = 216 */
1025 uschar src_addr[108];
1026 uschar dst_addr[108];
1032 /* Temp variables used in PPv2 address:port parsing */
1034 char tmpip[INET_ADDRSTRLEN];
1035 struct sockaddr_in tmpaddr;
1036 char tmpip6[INET6_ADDRSTRLEN];
1037 struct sockaddr_in6 tmpaddr6;
1039 /* We can't read "all data until end" because while SMTP is
1040 server-speaks-first, the TLS handshake is client-speaks-first, so for
1041 TLS-on-connect ports the proxy protocol header will usually be immediately
1042 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1043 reinject data for reading by those. So instead we first read "enough to be
1044 safely read within the header, and figure out how much more to read".
1045 For v1 we will later read to the end-of-line, for v2 we will read based upon
1048 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1049 data is needed total. For v1, where the line looks like:
1050 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1052 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1053 We seem to support that. So, if we read 14 octets then we can tell if we're
1054 v2 or v1. If we're v1, we can continue reading as normal.
1056 If we're v2, we can't slurp up the entire header. We need the length in the
1057 15th & 16th octets, then to read everything after that.
1059 So to safely handle v1 and v2, with client-sent-first supported correctly,
1060 we have to do a minimum of 3 read calls, not 1. Eww.
1063 #define PROXY_INITIAL_READ 14
1064 #define PROXY_V2_HEADER_SIZE 16
1065 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1066 # error Code bug in sizes of data to read for proxy usage
1071 int fd = fileno(smtp_in);
1072 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1073 uschar * iptype; /* To display debug info */
1075 struct timeval tvtmp;
1076 socklen_t vslen = sizeof(struct timeval);
1079 /* Save current socket timeout values */
1080 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1082 /* Proxy Protocol host must send header within a short time
1083 (default 3 seconds) or it's considered invalid */
1084 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1085 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1086 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1091 /* The inbound host was declared to be a Proxy Protocol host, so
1092 don't do a PEEK into the data, actually slurp up enough to be
1093 "safe". Can't take it all because TLS-on-connect clients follow
1094 immediately with TLS handshake. */
1095 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1097 while (ret == -1 && errno == EINTR);
1102 /* For v2, handle reading the length, and then the rest. */
1103 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1108 /* First get the length fields. */
1111 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1112 } while (retmore == -1 && errno == EINTR);
1117 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1119 /* May 2014: haproxy combined the version and command into one byte to
1120 allow two full bytes for the length field in order to proxy SSL
1121 connections. SSL Proxy is not supported in this version of Exim, but
1122 must still separate values here. */
1126 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1130 /* The v2 header will always be 16 bytes per the spec. */
1131 size = 16 + ntohs(hdr.v2.len);
1132 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1133 size, (int)sizeof(hdr));
1135 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1136 amount that we need. Double-check that the size is not unreasonable, then
1138 if (size > sizeof(hdr))
1140 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1148 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1149 } while (retmore == -1 && errno == EINTR);
1153 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1154 } while (ret < size);
1156 } /* end scope for getting rest of data for v2 */
1158 /* At this point: if PROXYv2, we've read the exact size required for all data;
1159 if PROXYv1 then we've read "less than required for any valid line" and should
1162 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1164 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1168 case 0x01: /* PROXY command */
1171 case 0x11: /* TCPv4 address type */
1173 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1174 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1175 if (!string_is_ip_address(US tmpip, NULL))
1177 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1180 proxy_local_address = sender_host_address;
1181 sender_host_address = string_copy(US tmpip);
1182 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1183 proxy_local_port = sender_host_port;
1184 sender_host_port = tmpport;
1185 /* Save dest ip/port */
1186 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1187 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1188 if (!string_is_ip_address(US tmpip, NULL))
1190 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1193 proxy_external_address = string_copy(US tmpip);
1194 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1195 proxy_external_port = tmpport;
1197 case 0x21: /* TCPv6 address type */
1199 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1200 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1201 if (!string_is_ip_address(US tmpip6, NULL))
1203 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1206 proxy_local_address = sender_host_address;
1207 sender_host_address = string_copy(US tmpip6);
1208 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1209 proxy_local_port = sender_host_port;
1210 sender_host_port = tmpport;
1211 /* Save dest ip/port */
1212 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1213 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1214 if (!string_is_ip_address(US tmpip6, NULL))
1216 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1219 proxy_external_address = string_copy(US tmpip6);
1220 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1221 proxy_external_port = tmpport;
1225 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1229 /* Unsupported protocol, keep local connection address */
1231 case 0x00: /* LOCAL command */
1232 /* Keep local connection address for LOCAL */
1237 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1241 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1245 uschar *sp; /* Utility variables follow */
1250 /* get the rest of the line */
1251 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1256 p = string_copy(hdr.v1.line);
1257 end = memchr(p, '\r', ret - 1);
1259 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1261 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1264 *end = '\0'; /* Terminate the string */
1265 size = end + 2 - p; /* Skip header + CRLF */
1266 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1267 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1268 /* Step through the string looking for the required fields. Ensure
1269 strict adherence to required formatting, exit for any error. */
1271 if (!isspace(*(p++)))
1273 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1276 if (!Ustrncmp(p, CCS"TCP4", 4))
1278 else if (!Ustrncmp(p,CCS"TCP6", 4))
1280 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1282 iptype = US"Unknown";
1287 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1291 p += Ustrlen(iptype);
1292 if (!isspace(*(p++)))
1294 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1297 /* Find the end of the arg */
1298 if ((sp = Ustrchr(p, ' ')) == NULL)
1301 debug_printf("Did not find proxied src %s\n", iptype);
1305 if(!string_is_ip_address(p, NULL))
1308 debug_printf("Proxied src arg is not an %s address\n", iptype);
1311 proxy_local_address = sender_host_address;
1312 sender_host_address = p;
1314 if ((sp = Ustrchr(p, ' ')) == NULL)
1317 debug_printf("Did not find proxy dest %s\n", iptype);
1321 if(!string_is_ip_address(p, NULL))
1324 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1327 proxy_external_address = p;
1329 if ((sp = Ustrchr(p, ' ')) == NULL)
1331 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1335 tmp_port = strtol(CCS p, &endc, 10);
1336 if (*endc || tmp_port == 0)
1339 debug_printf("Proxied src port '%s' not an integer\n", p);
1342 proxy_local_port = sender_host_port;
1343 sender_host_port = tmp_port;
1345 if ((sp = Ustrchr(p, '\0')) == NULL)
1347 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1350 tmp_port = strtol(CCS p, &endc, 10);
1351 if (*endc || tmp_port == 0)
1354 debug_printf("Proxy dest port '%s' not an integer\n", p);
1357 proxy_external_port = tmp_port;
1358 /* Already checked for /r /n above. Good V1 header received. */
1362 /* Wrong protocol */
1363 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1364 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1370 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1371 yield = proxy_session;
1373 /* Don't flush any potential buffer contents. Any input on proxyfail
1374 should cause a synchronization failure */
1377 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1382 sender_host_name = NULL;
1383 (void) host_name_lookup();
1384 host_build_sender_fullhost();
1388 proxy_session_failed = TRUE;
1390 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1397 /*************************************************
1398 * Read one command line *
1399 *************************************************/
1401 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1402 There are sites that don't do this, and in any case internal SMTP probably
1403 should check only for LF. Consequently, we check here for LF only. The line
1404 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1405 an unknown command. The command is read into the global smtp_cmd_buffer so that
1406 it is available via $smtp_command.
1408 The character reading routine sets up a timeout for each block actually read
1409 from the input (which may contain more than one command). We set up a special
1410 signal handler that closes down the session on a timeout. Control does not
1411 return when it runs.
1414 check_sync if TRUE, check synchronization rules if global option is TRUE
1415 buffer_lim maximum to buffer in lower layer
1417 Returns: a code identifying the command (enumerated above)
1421 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1426 BOOL hadnull = FALSE;
1428 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1430 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1432 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1434 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1442 smtp_cmd_buffer[ptr++] = c;
1445 receive_linecount++; /* For BSMTP errors */
1446 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1448 /* If hit end of file, return pseudo EOF command. Whether we have a
1449 part-line already read doesn't matter, since this is an error state. */
1451 if (c == EOF) return EOF_CMD;
1453 /* Remove any CR and white space at the end of the line, and terminate the
1456 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1457 smtp_cmd_buffer[ptr] = 0;
1459 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1461 /* NULLs are not allowed in SMTP commands */
1463 if (hadnull) return BADCHAR_CMD;
1465 /* Scan command list and return identity, having set the data pointer
1466 to the start of the actual data characters. Check for SMTP synchronization
1469 for (p = cmd_list; p < cmd_list_end; p++)
1471 #ifdef SUPPORT_PROXY
1472 /* Only allow QUIT command if Proxy Protocol parsing failed */
1473 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1477 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1478 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1479 || smtp_cmd_buffer[p->len] == 0
1480 || smtp_cmd_buffer[p->len] == ' '
1483 if (smtp_inptr < smtp_inend && /* Outstanding input */
1484 p->cmd < sync_cmd_limit && /* Command should sync */
1485 check_sync && /* Local flag set */
1486 smtp_enforce_sync && /* Global flag set */
1487 sender_host_address != NULL && /* Not local input */
1488 !sender_host_notsocket) /* Really is a socket */
1491 /* The variables $smtp_command and $smtp_command_argument point into the
1492 unmodified input buffer. A copy of the latter is taken for actual
1493 processing, so that it can be chopped up into separate parts if necessary,
1494 for example, when processing a MAIL command options such as SIZE that can
1495 follow the sender address. */
1497 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1498 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1499 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1500 smtp_cmd_data = smtp_data_buffer;
1502 /* Count non-mail commands from those hosts that are controlled in this
1503 way. The default is all hosts. We don't waste effort checking the list
1504 until we get a non-mail command, but then cache the result to save checking
1505 again. If there's a DEFER while checking the host, assume it's in the list.
1507 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1508 start of each incoming message by fiddling with the value in the table. */
1510 if (!p->is_mail_cmd)
1512 if (count_nonmail == TRUE_UNSET) count_nonmail =
1513 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1514 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1515 return TOO_MANY_NONMAIL_CMD;
1518 /* If there is data for a command that does not expect it, generate the
1521 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1525 #ifdef SUPPORT_PROXY
1526 /* Only allow QUIT command if Proxy Protocol parsing failed */
1527 if (proxy_session && proxy_session_failed)
1528 return PROXY_FAIL_IGNORE_CMD;
1531 /* Enforce synchronization for unknown commands */
1533 if (smtp_inptr < smtp_inend && /* Outstanding input */
1534 check_sync && /* Local flag set */
1535 smtp_enforce_sync && /* Global flag set */
1536 sender_host_address != NULL && /* Not local input */
1537 !sender_host_notsocket) /* Really is a socket */
1545 /*************************************************
1546 * Forced closedown of call *
1547 *************************************************/
1549 /* This function is called from log.c when Exim is dying because of a serious
1550 disaster, and also from some other places. If an incoming non-batched SMTP
1551 channel is open, it swallows the rest of the incoming message if in the DATA
1552 phase, sends the reply string, and gives an error to all subsequent commands
1553 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1557 message SMTP reply string to send, excluding the code
1563 smtp_closedown(uschar *message)
1565 if (smtp_in == NULL || smtp_batched_input) return;
1566 receive_swallow_smtp();
1567 smtp_printf("421 %s\r\n", message);
1569 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1575 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1580 smtp_printf("250 Reset OK\r\n");
1584 smtp_printf("421 %s\r\n", message);
1592 /*************************************************
1593 * Set up connection info for logging *
1594 *************************************************/
1596 /* This function is called when logging information about an SMTP connection.
1597 It sets up appropriate source information, depending on the type of connection.
1598 If sender_fullhost is NULL, we are at a very early stage of the connection;
1599 just use the IP address.
1602 Returns: a string describing the connection
1606 smtp_get_connection_info(void)
1608 const uschar * hostname = sender_fullhost
1609 ? sender_fullhost : sender_host_address;
1612 return string_sprintf("SMTP connection from %s", hostname);
1614 if (sender_host_unknown || sender_host_notsocket)
1615 return string_sprintf("SMTP connection from %s", sender_ident);
1618 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1620 if (LOGGING(incoming_interface) && interface_address != NULL)
1621 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1622 interface_address, interface_port);
1624 return string_sprintf("SMTP connection from %s", hostname);
1630 /* Append TLS-related information to a log line
1633 s String under construction: allocated string to extend, or NULL
1634 sizep Pointer to current allocation size (update on return), or NULL
1635 ptrp Pointer to index for new entries in string (update on return), or NULL
1637 Returns: Allocated string or NULL
1640 s_tlslog(uschar * s, int * sizep, int * ptrp)
1642 int size = sizep ? *sizep : 0;
1643 int ptr = ptrp ? *ptrp : 0;
1645 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1646 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1647 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1648 s = string_append(s, &size, &ptr, 2, US" CV=",
1649 tls_in.certificate_verified? "yes":"no");
1650 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1651 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1652 string_printing(tls_in.peerdn), US"\"");
1653 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1654 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1655 string_printing(tls_in.sni), US"\"");
1660 if (sizep) *sizep = size;
1661 if (ptrp) *ptrp = ptr;
1667 /*************************************************
1668 * Log lack of MAIL if so configured *
1669 *************************************************/
1671 /* This function is called when an SMTP session ends. If the log selector
1672 smtp_no_mail is set, write a log line giving some details of what has happened
1673 in the SMTP session.
1680 smtp_log_no_mail(void)
1685 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1691 if (sender_host_authenticated != NULL)
1693 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1694 if (authenticated_id != NULL)
1695 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1699 s = s_tlslog(s, &size, &ptr);
1702 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1703 US" C=..." : US" C=";
1704 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1706 if (smtp_connection_had[i] != SCH_NONE)
1708 s = string_append(s, &size, &ptr, 2, sep,
1709 smtp_names[smtp_connection_had[i]]);
1714 for (i = 0; i < smtp_ch_index; i++)
1716 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1720 if (s != NULL) s[ptr] = 0; else s = US"";
1721 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1722 host_and_ident(FALSE),
1723 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1729 /*************************************************
1730 * Check HELO line and set sender_helo_name *
1731 *************************************************/
1733 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1734 the domain name of the sending host, or an ip literal in square brackets. The
1735 argument is placed in sender_helo_name, which is in malloc store, because it
1736 must persist over multiple incoming messages. If helo_accept_junk is set, this
1737 host is permitted to send any old junk (needed for some broken hosts).
1738 Otherwise, helo_allow_chars can be used for rogue characters in general
1739 (typically people want to let in underscores).
1742 s the data portion of the line (already past any white space)
1744 Returns: TRUE or FALSE
1748 check_helo(uschar *s)
1751 uschar *end = s + Ustrlen(s);
1752 BOOL yield = helo_accept_junk;
1754 /* Discard any previous helo name */
1756 if (sender_helo_name != NULL)
1758 store_free(sender_helo_name);
1759 sender_helo_name = NULL;
1762 /* Skip tests if junk is permitted. */
1766 /* Allow the new standard form for IPv6 address literals, namely,
1767 [IPv6:....], and because someone is bound to use it, allow an equivalent
1768 IPv4 form. Allow plain addresses as well. */
1775 if (strncmpic(s, US"[IPv6:", 6) == 0)
1776 yield = (string_is_ip_address(s+6, NULL) == 6);
1777 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1778 yield = (string_is_ip_address(s+6, NULL) == 4);
1780 yield = (string_is_ip_address(s+1, NULL) != 0);
1785 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1786 that have been configured (usually underscore - sigh). */
1793 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1794 Ustrchr(helo_allow_chars, *s) == NULL)
1804 /* Save argument if OK */
1806 if (yield) sender_helo_name = string_copy_malloc(start);
1814 /*************************************************
1815 * Extract SMTP command option *
1816 *************************************************/
1818 /* This function picks the next option setting off the end of smtp_cmd_data. It
1819 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1820 things that can appear there.
1823 name point this at the name
1824 value point this at the data string
1826 Returns: TRUE if found an option
1830 extract_option(uschar **name, uschar **value)
1833 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1834 while (isspace(*v)) v--;
1836 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1838 /* Take care to not stop at a space embedded in a quoted local-part */
1840 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1847 while(isalpha(n[-1])) n--;
1848 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1849 if (!isspace(n[-1])) return FALSE;
1855 if (v == smtp_cmd_data) return FALSE;
1867 /*************************************************
1868 * Reset for new message *
1869 *************************************************/
1871 /* This function is called whenever the SMTP session is reset from
1872 within either of the setup functions.
1874 Argument: the stacking pool storage reset point
1879 smtp_reset(void *reset_point)
1881 store_reset(reset_point);
1882 recipients_list = NULL;
1883 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1884 raw_recipients_count = recipients_count = recipients_list_max = 0;
1885 cancel_cutthrough_connection("smtp reset");
1886 message_linecount = 0;
1888 acl_added_headers = NULL;
1889 acl_removed_headers = NULL;
1890 queue_only_policy = FALSE;
1891 rcpt_smtp_response = NULL;
1892 rcpt_smtp_response_same = TRUE;
1893 rcpt_in_progress = FALSE;
1894 deliver_freeze = FALSE; /* Can be set by ACL */
1895 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1896 fake_response = OK; /* Can be set by ACL */
1897 #ifdef WITH_CONTENT_SCAN
1898 no_mbox_unspool = FALSE; /* Can be set by ACL */
1900 submission_mode = FALSE; /* Can be set by ACL */
1901 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1902 active_local_from_check = local_from_check; /* Can be set by ACL */
1903 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1904 sender_address = NULL;
1905 submission_name = NULL; /* Can be set by ACL */
1906 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1907 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1908 sender_verified_list = NULL; /* No senders verified */
1909 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1910 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1912 authenticated_sender = NULL;
1913 #ifdef EXPERIMENTAL_BRIGHTMAIL
1915 bmi_verdicts = NULL;
1917 #ifndef DISABLE_DKIM
1918 dkim_signers = NULL;
1919 dkim_disable_verify = FALSE;
1920 dkim_collect_input = FALSE;
1924 #ifndef DISABLE_PRDR
1925 prdr_requested = FALSE;
1927 #ifdef EXPERIMENTAL_SPF
1928 spf_header_comment = NULL;
1929 spf_received = NULL;
1931 spf_smtp_comment = NULL;
1934 message_smtputf8 = FALSE;
1936 body_linecount = body_zerocount = 0;
1938 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1939 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1940 /* Note that ratelimiters_conn persists across resets. */
1942 /* Reset message ACL variables */
1946 /* The message body variables use malloc store. They may be set if this is
1947 not the first message in an SMTP session and the previous message caused them
1948 to be referenced in an ACL. */
1950 if (message_body != NULL)
1952 store_free(message_body);
1953 message_body = NULL;
1956 if (message_body_end != NULL)
1958 store_free(message_body_end);
1959 message_body_end = NULL;
1962 /* Warning log messages are also saved in malloc store. They are saved to avoid
1963 repetition in the same message, but it seems right to repeat them for different
1966 while (acl_warn_logged != NULL)
1968 string_item *this = acl_warn_logged;
1969 acl_warn_logged = acl_warn_logged->next;
1978 /*************************************************
1979 * Initialize for incoming batched SMTP message *
1980 *************************************************/
1982 /* This function is called from smtp_setup_msg() in the case when
1983 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1984 of messages in one file with SMTP commands between them. All errors must be
1985 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1986 relevant. After an error on a sender, or an invalid recipient, the remainder
1987 of the message is skipped. The value of received_protocol is already set.
1990 Returns: > 0 message successfully started (reached DATA)
1991 = 0 QUIT read or end of file reached
1992 < 0 should not occur
1996 smtp_setup_batch_msg(void)
1999 void *reset_point = store_get(0);
2001 /* Save the line count at the start of each transaction - single commands
2002 like HELO and RSET count as whole transactions. */
2004 bsmtp_transaction_linecount = receive_linecount;
2006 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2008 smtp_reset(reset_point); /* Reset for start of message */
2010 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2011 value. The values are 2 larger than the required yield of the function. */
2016 uschar *recipient = NULL;
2017 int start, end, sender_domain, recipient_domain;
2019 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2021 /* The HELO/EHLO commands set sender_address_helo if they have
2022 valid data; otherwise they are ignored, except that they do
2023 a reset of the state. */
2028 check_helo(smtp_cmd_data);
2032 smtp_reset(reset_point);
2033 bsmtp_transaction_linecount = receive_linecount;
2037 /* The MAIL FROM command requires an address as an operand. All we
2038 do here is to parse it for syntactic correctness. The form "<>" is
2039 a special case which converts into an empty string. The start/end
2040 pointers in the original are not used further for this address, as
2041 it is the canonical extracted address which is all that is kept. */
2044 smtp_mailcmd_count++; /* Count for no-mail log */
2045 if (sender_address != NULL)
2046 /* The function moan_smtp_batch() does not return. */
2047 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2049 if (smtp_cmd_data[0] == 0)
2050 /* The function moan_smtp_batch() does not return. */
2051 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2053 /* Reset to start of message */
2055 smtp_reset(reset_point);
2057 /* Apply SMTP rewrite */
2059 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2060 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2061 US"", global_rewrite_rules) : smtp_cmd_data;
2063 /* Extract the address; the TRUE flag allows <> as valid */
2066 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2069 if (raw_sender == NULL)
2070 /* The function moan_smtp_batch() does not return. */
2071 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2073 sender_address = string_copy(raw_sender);
2075 /* Qualify unqualified sender addresses if permitted to do so. */
2077 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2079 if (allow_unqualified_sender)
2081 sender_address = rewrite_address_qualify(sender_address, FALSE);
2082 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2083 "and rewritten\n", raw_sender);
2085 /* The function moan_smtp_batch() does not return. */
2086 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2092 /* The RCPT TO command requires an address as an operand. All we do
2093 here is to parse it for syntactic correctness. There may be any number
2094 of RCPT TO commands, specifying multiple senders. We build them all into
2095 a data structure that is in argc/argv format. The start/end values
2096 given by parse_extract_address are not used, as we keep only the
2097 extracted address. */
2100 if (sender_address == NULL)
2101 /* The function moan_smtp_batch() does not return. */
2102 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2104 if (smtp_cmd_data[0] == 0)
2105 /* The function moan_smtp_batch() does not return. */
2106 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2108 /* Check maximum number allowed */
2110 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2111 /* The function moan_smtp_batch() does not return. */
2112 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2113 recipients_max_reject? "552": "452");
2115 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2116 recipient address */
2118 recipient = rewrite_existflags & rewrite_smtp
2119 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2120 global_rewrite_rules)
2123 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2124 &recipient_domain, FALSE);
2127 /* The function moan_smtp_batch() does not return. */
2128 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2130 /* If the recipient address is unqualified, qualify it if permitted. Then
2131 add it to the list of recipients. */
2133 if (recipient_domain == 0)
2135 if (allow_unqualified_recipient)
2137 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2139 recipient = rewrite_address_qualify(recipient, TRUE);
2141 /* The function moan_smtp_batch() does not return. */
2142 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2145 receive_add_recipient(recipient, -1);
2149 /* The DATA command is legal only if it follows successful MAIL FROM
2150 and RCPT TO commands. This function is complete when a valid DATA
2151 command is encountered. */
2154 if (sender_address == NULL || recipients_count <= 0)
2156 /* The function moan_smtp_batch() does not return. */
2157 if (sender_address == NULL)
2158 moan_smtp_batch(smtp_cmd_buffer,
2159 "503 MAIL FROM:<sender> command must precede DATA");
2161 moan_smtp_batch(smtp_cmd_buffer,
2162 "503 RCPT TO:<recipient> must precede DATA");
2166 done = 3; /* DATA successfully achieved */
2167 message_ended = END_NOTENDED; /* Indicate in middle of message */
2172 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2179 bsmtp_transaction_linecount = receive_linecount;
2190 /* The function moan_smtp_batch() does not return. */
2191 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2196 /* The function moan_smtp_batch() does not return. */
2197 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2202 /* The function moan_smtp_batch() does not return. */
2203 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2208 return done - 2; /* Convert yield values */
2214 /*************************************************
2215 * Start an SMTP session *
2216 *************************************************/
2218 /* This function is called at the start of an SMTP session. Thereafter,
2219 smtp_setup_msg() is called to initiate each separate message. This
2220 function does host-specific testing, and outputs the banner line.
2223 Returns: FALSE if the session can not continue; something has
2224 gone wrong, or the connection to the host is blocked
2228 smtp_start_session(void)
2232 uschar *user_msg, *log_msg;
2236 smtp_connection_start = time(NULL);
2237 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2238 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2241 /* Default values for certain variables */
2243 helo_seen = esmtp = helo_accept_junk = FALSE;
2244 smtp_mailcmd_count = 0;
2245 count_nonmail = TRUE_UNSET;
2246 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2247 smtp_delay_mail = smtp_rlm_base;
2248 auth_advertised = FALSE;
2249 pipelining_advertised = FALSE;
2250 pipelining_enable = TRUE;
2251 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2252 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2254 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2255 authentication settings from -oMaa to remain in force. */
2257 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2258 authenticated_by = NULL;
2261 tls_in.cipher = tls_in.peerdn = NULL;
2262 tls_in.ourcert = tls_in.peercert = NULL;
2264 tls_in.ocsp = OCSP_NOT_REQ;
2265 tls_advertised = FALSE;
2267 dsn_advertised = FALSE;
2269 smtputf8_advertised = FALSE;
2272 /* Reset ACL connection variables */
2276 /* Allow for trailing 0 in the command and data buffers. */
2278 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2279 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2280 "malloc() failed for SMTP command buffer");
2282 smtp_cmd_buffer[0] = 0;
2283 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2285 /* For batched input, the protocol setting can be overridden from the
2286 command line by a trusted caller. */
2288 if (smtp_batched_input)
2290 if (!received_protocol) received_protocol = US"local-bsmtp";
2293 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2294 reset later if any of EHLO/AUTH/STARTTLS are received. */
2298 (sender_host_address ? protocols : protocols_local) [pnormal];
2300 /* Set up the buffer for inputting using direct read() calls, and arrange to
2301 call the local functions instead of the standard C ones. */
2303 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2304 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2306 receive_getc = smtp_getc;
2307 receive_get_cache = smtp_get_cache;
2308 receive_ungetc = smtp_ungetc;
2309 receive_feof = smtp_feof;
2310 receive_ferror = smtp_ferror;
2311 receive_smtp_buffered = smtp_buffered;
2312 smtp_inptr = smtp_inend = smtp_inbuffer;
2313 smtp_had_eof = smtp_had_error = 0;
2315 /* Set up the message size limit; this may be host-specific */
2317 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2318 if (expand_string_message != NULL)
2320 if (thismessage_size_limit == -1)
2321 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2322 "%s", expand_string_message);
2324 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2325 "%s", expand_string_message);
2326 smtp_closedown(US"Temporary local problem - please try later");
2330 /* When a message is input locally via the -bs or -bS options, sender_host_
2331 unknown is set unless -oMa was used to force an IP address, in which case it
2332 is checked like a real remote connection. When -bs is used from inetd, this
2333 flag is not set, causing the sending host to be checked. The code that deals
2334 with IP source routing (if configured) is never required for -bs or -bS and
2335 the flag sender_host_notsocket is used to suppress it.
2337 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2338 reserve for certain hosts and/or networks. */
2340 if (!sender_host_unknown)
2343 BOOL reserved_host = FALSE;
2345 /* Look up IP options (source routing info) on the socket if this is not an
2346 -oMa "host", and if any are found, log them and drop the connection.
2348 Linux (and others now, see below) is different to everyone else, so there
2349 has to be some conditional compilation here. Versions of Linux before 2.1.15
2350 used a structure whose name was "options". Somebody finally realized that
2351 this name was silly, and it got changed to "ip_options". I use the
2352 newer name here, but there is a fudge in the script that sets up os.h
2353 to define a macro in older Linux systems.
2355 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2356 glibc 2, which has chosen ip_opts for the structure name. This is now
2357 really a glibc thing rather than a Linux thing, so the condition name
2358 has been changed to reflect this. It is relevant also to GNU/Hurd.
2360 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2361 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2362 a special macro defined in the os.h file.
2364 Some DGUX versions on older hardware appear not to support IP options at
2365 all, so there is now a general macro which can be set to cut out this
2368 How to do this properly in IPv6 is not yet known. */
2370 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2372 #ifdef GLIBC_IP_OPTIONS
2373 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2378 #elif defined DARWIN_IP_OPTIONS
2384 if (!host_checking && !sender_host_notsocket)
2387 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2388 struct ip_options *ipopt = store_get(optlen);
2390 struct ip_opts ipoptblock;
2391 struct ip_opts *ipopt = &ipoptblock;
2392 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2394 struct ipoption ipoptblock;
2395 struct ipoption *ipopt = &ipoptblock;
2396 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2399 /* Occasional genuine failures of getsockopt() have been seen - for
2400 example, "reset by peer". Therefore, just log and give up on this
2401 call, unless the error is ENOPROTOOPT. This error is given by systems
2402 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2403 of writing. So for that error, carry on - we just can't do an IP options
2406 DEBUG(D_receive) debug_printf("checking for IP options\n");
2408 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2411 if (errno != ENOPROTOOPT)
2413 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2414 host_and_ident(FALSE), strerror(errno));
2415 smtp_printf("451 SMTP service not available\r\n");
2420 /* Deal with any IP options that are set. On the systems I have looked at,
2421 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2422 more logging data than will fit in big_buffer. Nevertheless, after somebody
2423 questioned this code, I've added in some paranoid checking. */
2425 else if (optlen > 0)
2427 uschar *p = big_buffer;
2428 uschar *pend = big_buffer + big_buffer_size;
2429 uschar *opt, *adptr;
2431 struct in_addr addr;
2434 uschar *optstart = (uschar *)(ipopt->__data);
2436 uschar *optstart = (uschar *)(ipopt->ip_opts);
2438 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2441 DEBUG(D_receive) debug_printf("IP options exist\n");
2443 Ustrcpy(p, "IP options on incoming call:");
2446 for (opt = optstart; opt != NULL &&
2447 opt < (uschar *)(ipopt) + optlen;)
2461 if (!string_format(p, pend-p, " %s [@%s",
2462 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2464 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2466 inet_ntoa(ipopt->ip_dst)))
2468 inet_ntoa(ipopt->ipopt_dst)))
2476 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2478 while (optcount-- > 0)
2480 memcpy(&addr, adptr, sizeof(addr));
2481 if (!string_format(p, pend - p - 1, "%s%s",
2482 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2488 adptr += sizeof(struct in_addr);
2497 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2500 for (i = 0; i < opt[1]; i++)
2502 sprintf(CS p, "%2.2x ", opt[i]);
2513 log_write(0, LOG_MAIN, "%s", big_buffer);
2515 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2517 log_write(0, LOG_MAIN|LOG_REJECT,
2518 "connection from %s refused (IP options)", host_and_ident(FALSE));
2520 smtp_printf("554 SMTP service not available\r\n");
2524 /* Length of options = 0 => there are no options */
2526 else DEBUG(D_receive) debug_printf("no IP options found\n");
2528 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2530 /* Set keep-alive in socket options. The option is on by default. This
2531 setting is an attempt to get rid of some hanging connections that stick in
2532 read() when the remote end (usually a dialup) goes away. */
2534 if (smtp_accept_keepalive && !sender_host_notsocket)
2535 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2537 /* If the current host matches host_lookup, set the name by doing a
2538 reverse lookup. On failure, sender_host_name will be NULL and
2539 host_lookup_failed will be TRUE. This may or may not be serious - optional
2542 if (verify_check_host(&host_lookup) == OK)
2544 (void)host_name_lookup();
2545 host_build_sender_fullhost();
2548 /* Delay this until we have the full name, if it is looked up. */
2550 set_process_info("handling incoming connection from %s",
2551 host_and_ident(FALSE));
2553 /* Expand smtp_receive_timeout, if needed */
2555 if (smtp_receive_timeout_s)
2558 if ( !(exp = expand_string(smtp_receive_timeout_s))
2560 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2562 log_write(0, LOG_MAIN|LOG_PANIC,
2563 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2566 /* Test for explicit connection rejection */
2568 if (verify_check_host(&host_reject_connection) == OK)
2570 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2571 "from %s (host_reject_connection)", host_and_ident(FALSE));
2572 smtp_printf("554 SMTP service not available\r\n");
2576 /* Test with TCP Wrappers if so configured. There is a problem in that
2577 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2578 such as disks dying. In these cases, it is desirable to reject with a 4xx
2579 error instead of a 5xx error. There isn't a "right" way to detect such
2580 problems. The following kludge is used: errno is zeroed before calling
2581 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2582 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2585 #ifdef USE_TCP_WRAPPERS
2587 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2588 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2589 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2590 expand_string_message);
2592 if (!hosts_ctl(tcp_wrappers_name,
2593 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2594 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2595 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2597 if (errno == 0 || errno == ENOENT)
2599 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2600 log_write(L_connection_reject,
2601 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2602 "(tcp wrappers)", host_and_ident(FALSE));
2603 smtp_printf("554 SMTP service not available\r\n");
2607 int save_errno = errno;
2608 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2609 "errno value %d\n", save_errno);
2610 log_write(L_connection_reject,
2611 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2612 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2613 smtp_printf("451 Temporary local problem - please try later\r\n");
2619 /* Check for reserved slots. The value of smtp_accept_count has already been
2620 incremented to include this process. */
2622 if (smtp_accept_max > 0 &&
2623 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2625 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2627 log_write(L_connection_reject,
2628 LOG_MAIN, "temporarily refused connection from %s: not in "
2629 "reserve list: connected=%d max=%d reserve=%d%s",
2630 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2631 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2632 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2633 "please try again later\r\n", smtp_active_hostname);
2636 reserved_host = TRUE;
2639 /* If a load level above which only messages from reserved hosts are
2640 accepted is set, check the load. For incoming calls via the daemon, the
2641 check is done in the superior process if there are no reserved hosts, to
2642 save a fork. In all cases, the load average will already be available
2643 in a global variable at this point. */
2645 if (smtp_load_reserve >= 0 &&
2646 load_average > smtp_load_reserve &&
2648 verify_check_host(&smtp_reserve_hosts) != OK)
2650 log_write(L_connection_reject,
2651 LOG_MAIN, "temporarily refused connection from %s: not in "
2652 "reserve list and load average = %.2f", host_and_ident(FALSE),
2653 (double)load_average/1000.0);
2654 smtp_printf("421 %s: Too much load; please try again later\r\n",
2655 smtp_active_hostname);
2659 /* Determine whether unqualified senders or recipients are permitted
2660 for this host. Unfortunately, we have to do this every time, in order to
2661 set the flags so that they can be inspected when considering qualifying
2662 addresses in the headers. For a site that permits no qualification, this
2663 won't take long, however. */
2665 allow_unqualified_sender =
2666 verify_check_host(&sender_unqualified_hosts) == OK;
2668 allow_unqualified_recipient =
2669 verify_check_host(&recipient_unqualified_hosts) == OK;
2671 /* Determine whether HELO/EHLO is required for this host. The requirement
2672 can be hard or soft. */
2674 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2676 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2678 /* Determine whether this hosts is permitted to send syntactic junk
2679 after a HELO or EHLO command. */
2681 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2684 /* For batch SMTP input we are now done. */
2686 if (smtp_batched_input) return TRUE;
2688 /* If valid Proxy Protocol source is connecting, set up session.
2689 * Failure will not allow any SMTP function other than QUIT. */
2691 #ifdef SUPPORT_PROXY
2692 proxy_session = FALSE;
2693 proxy_session_failed = FALSE;
2694 if (check_proxy_protocol_host())
2695 setup_proxy_protocol_host();
2698 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2699 smtps port for use with older style SSL MTAs. */
2702 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2706 /* Run the connect ACL if it exists */
2709 if (acl_smtp_connect)
2712 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2715 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2720 /* Output the initial message for a two-way SMTP connection. It may contain
2721 newlines, which then cause a multi-line response to be given. */
2723 code = US"220"; /* Default status code */
2724 esc = US""; /* Default extended status code */
2725 esclen = 0; /* Length of esc */
2729 if (!(s = expand_string(smtp_banner)))
2730 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2731 "failed: %s", smtp_banner, expand_string_message);
2737 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2741 esclen = codelen - 4;
2745 /* Remove any terminating newlines; might as well remove trailing space too */
2748 while (p > s && isspace(p[-1])) p--;
2751 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2752 is all contained in a single IP packet. The original code wrote out the
2753 greeting using several calls to fprint/fputc, and on busy servers this could
2754 cause it to be split over more than one packet - which caused CC:Mail to fall
2755 over when it got the second part of the greeting after sending its first
2756 command. Sigh. To try to avoid this, build the complete greeting message
2757 first, and output it in one fell swoop. This gives a better chance of it
2758 ending up as a single packet. */
2760 ss = store_get(size);
2764 do /* At least once, in case we have an empty string */
2767 uschar *linebreak = Ustrchr(p, '\n');
2768 ss = string_catn(ss, &size, &ptr, code, 3);
2769 if (linebreak == NULL)
2772 ss = string_catn(ss, &size, &ptr, US" ", 1);
2776 len = linebreak - p;
2777 ss = string_catn(ss, &size, &ptr, US"-", 1);
2779 ss = string_catn(ss, &size, &ptr, esc, esclen);
2780 ss = string_catn(ss, &size, &ptr, p, len);
2781 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2783 if (linebreak != NULL) p++;
2787 ss[ptr] = 0; /* string_cat leaves room for this */
2789 /* Before we write the banner, check that there is no input pending, unless
2790 this synchronisation check is disabled. */
2794 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2795 "synchronization error (input sent without waiting for greeting): "
2796 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2797 string_printing(smtp_inptr));
2798 smtp_printf("554 SMTP synchronization error\r\n");
2802 /* Now output the banner */
2804 smtp_printf("%s", ss);
2812 /*************************************************
2813 * Handle SMTP syntax and protocol errors *
2814 *************************************************/
2816 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2817 to do so. Then transmit the error response. The return value depends on the
2818 number of syntax and protocol errors in this SMTP session.
2821 type error type, given as a log flag bit
2822 code response code; <= 0 means don't send a response
2823 data data to reflect in the response (can be NULL)
2824 errmess the error message
2826 Returns: -1 limit of syntax/protocol errors NOT exceeded
2827 +1 limit of syntax/protocol errors IS exceeded
2829 These values fit in with the values of the "done" variable in the main
2830 processing loop in smtp_setup_msg(). */
2833 synprot_error(int type, int code, uschar *data, uschar *errmess)
2837 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2838 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2839 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2841 if (++synprot_error_count > smtp_max_synprot_errors)
2844 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2845 "syntax or protocol errors (last command was \"%s\")",
2846 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2851 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2852 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2854 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2863 /*************************************************
2864 * Send SMTP response, possibly multiline *
2865 *************************************************/
2867 /* There are, it seems, broken clients out there that cannot handle multiline
2868 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2869 output nothing for non-final calls, and only the first line for anything else.
2872 code SMTP code, may involve extended status codes
2873 codelen length of smtp code; if > 4 there's an ESC
2874 final FALSE if the last line isn't the final line
2875 msg message text, possibly containing newlines
2881 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2886 if (!final && no_multiline_responses) return;
2891 esclen = codelen - 4;
2894 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2895 have had the same. Note: this code is also present in smtp_printf(). It would
2896 be tidier to have it only in one place, but when it was added, it was easier to
2897 do it that way, so as not to have to mess with the code for the RCPT command,
2898 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2900 if (rcpt_in_progress)
2902 if (rcpt_smtp_response == NULL)
2903 rcpt_smtp_response = string_copy(msg);
2904 else if (rcpt_smtp_response_same &&
2905 Ustrcmp(rcpt_smtp_response, msg) != 0)
2906 rcpt_smtp_response_same = FALSE;
2907 rcpt_in_progress = FALSE;
2910 /* Not output the message, splitting it up into multiple lines if necessary. */
2914 uschar *nl = Ustrchr(msg, '\n');
2917 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2920 else if (nl[1] == 0 || no_multiline_responses)
2922 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2923 (int)(nl - msg), msg);
2928 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2930 while (isspace(*msg)) msg++;
2938 /*************************************************
2939 * Parse user SMTP message *
2940 *************************************************/
2942 /* This function allows for user messages overriding the response code details
2943 by providing a suitable response code string at the start of the message
2944 user_msg. Check the message for starting with a response code and optionally an
2945 extended status code. If found, check that the first digit is valid, and if so,
2946 change the code pointer and length to use the replacement. An invalid code
2947 causes a panic log; in this case, if the log messages is the same as the user
2948 message, we must also adjust the value of the log message to show the code that
2949 is actually going to be used (the original one).
2951 This function is global because it is called from receive.c as well as within
2954 Note that the code length returned includes the terminating whitespace
2955 character, which is always included in the regex match.
2958 code SMTP code, may involve extended status codes
2959 codelen length of smtp code; if > 4 there's an ESC
2961 log_msg optional log message, to be adjusted with the new SMTP code
2962 check_valid if true, verify the response code
2968 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2974 if (!msg || !*msg) return;
2976 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2977 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2979 if (check_valid && (*msg)[0] != (*code)[0])
2981 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2982 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2983 if (log_msg != NULL && *log_msg == *msg)
2984 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2989 *codelen = ovector[1]; /* Includes final space */
2991 *msg += ovector[1]; /* Chop the code off the message */
2998 /*************************************************
2999 * Handle an ACL failure *
3000 *************************************************/
3002 /* This function is called when acl_check() fails. As well as calls from within
3003 this module, it is called from receive.c for an ACL after DATA. It sorts out
3004 logging the incident, and sets up the error response. A message containing
3005 newlines is turned into a multiline SMTP response, but for logging, only the
3008 There's a table of default permanent failure response codes to use in
3009 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3010 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3011 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3012 state, because there are broken clients that try VRFY before RCPT. A 5xx
3013 response should be given only when the address is positively known to be
3014 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3015 no explicit code, but if there is one we let it know best.
3016 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3018 From Exim 4.63, it is possible to override the response code details by
3019 providing a suitable response code string at the start of the message provided
3020 in user_msg. The code's first digit is checked for validity.
3023 where where the ACL was called from
3025 user_msg a message that can be included in an SMTP response
3026 log_msg a message for logging
3028 Returns: 0 in most cases
3029 2 if the failure code was FAIL_DROP, in which case the
3030 SMTP connection should be dropped (this value fits with the
3031 "done" variable in smtp_setup_msg() below)
3035 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3037 BOOL drop = rc == FAIL_DROP;
3041 uschar *sender_info = US"";
3043 #ifdef WITH_CONTENT_SCAN
3044 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3046 where == ACL_WHERE_PREDATA ? US"DATA" :
3047 where == ACL_WHERE_DATA ? US"after DATA" :
3048 #ifndef DISABLE_PRDR
3049 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3052 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3053 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3055 if (drop) rc = FAIL;
3057 /* Set the default SMTP code, and allow a user message to change it. */
3059 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3060 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3061 where != ACL_WHERE_VRFY);
3063 /* We used to have sender_address here; however, there was a bug that was not
3064 updating sender_address after a rewrite during a verify. When this bug was
3065 fixed, sender_address at this point became the rewritten address. I'm not sure
3066 this is what should be logged, so I've changed to logging the unrewritten
3067 address to retain backward compatibility. */
3069 #ifndef WITH_CONTENT_SCAN
3070 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3072 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3075 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3076 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3077 sender_host_authenticated ? US" A=" : US"",
3078 sender_host_authenticated ? sender_host_authenticated : US"",
3079 sender_host_authenticated && authenticated_id ? US":" : US"",
3080 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3084 /* If there's been a sender verification failure with a specific message, and
3085 we have not sent a response about it yet, do so now, as a preliminary line for
3086 failures, but not defers. However, always log it for defer, and log it for fail
3087 unless the sender_verify_fail log selector has been turned off. */
3089 if (sender_verified_failed &&
3090 !testflag(sender_verified_failed, af_sverify_told))
3092 BOOL save_rcpt_in_progress = rcpt_in_progress;
3093 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3095 setflag(sender_verified_failed, af_sverify_told);
3097 if (rc != FAIL || LOGGING(sender_verify_fail))
3098 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3099 host_and_ident(TRUE),
3100 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3101 sender_verified_failed->address,
3102 (sender_verified_failed->message == NULL)? US"" :
3103 string_sprintf(": %s", sender_verified_failed->message));
3105 if (rc == FAIL && sender_verified_failed->user_message)
3106 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3107 testflag(sender_verified_failed, af_verify_pmfail)?
3108 "Postmaster verification failed while checking <%s>\n%s\n"
3109 "Several RFCs state that you are required to have a postmaster\n"
3110 "mailbox for each mail domain. This host does not accept mail\n"
3111 "from domains whose servers reject the postmaster address."
3113 testflag(sender_verified_failed, af_verify_nsfail)?
3114 "Callback setup failed while verifying <%s>\n%s\n"
3115 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3116 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3117 "RFC requirements, and stops you from receiving standard bounce\n"
3118 "messages. This host does not accept mail from domains whose servers\n"
3121 "Verification failed for <%s>\n%s",
3122 sender_verified_failed->address,
3123 sender_verified_failed->user_message));
3125 rcpt_in_progress = save_rcpt_in_progress;
3128 /* Sort out text for logging */
3130 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3131 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3133 /* Send permanent failure response to the command, but the code used isn't
3134 always a 5xx one - see comments at the start of this function. If the original
3135 rc was FAIL_DROP we drop the connection and yield 2. */
3138 smtp_respond(smtp_code, codelen, TRUE,
3139 user_msg ? user_msg : US"Administrative prohibition");
3141 /* Send temporary failure response to the command. Don't give any details,
3142 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3143 verb, and for a header verify when smtp_return_error_details is set.
3145 This conditional logic is all somewhat of a mess because of the odd
3146 interactions between temp_details and return_error_details. One day it should
3147 be re-implemented in a tidier fashion. */
3150 if (acl_temp_details && user_msg)
3152 if ( smtp_return_error_details
3153 && sender_verified_failed
3154 && sender_verified_failed->message
3156 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3158 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3161 smtp_respond(smtp_code, codelen, TRUE,
3162 US"Temporary local problem - please try later");
3164 /* Log the incident to the logs that are specified by log_reject_target
3165 (default main, reject). This can be empty to suppress logging of rejections. If
3166 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3167 is closing if required and return 2. */
3169 if (log_reject_target != 0)
3172 uschar * tls = s_tlslog(NULL, NULL, NULL);
3173 if (!tls) tls = US"";
3175 uschar * tls = US"";
3177 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3178 log_reject_target, "%s%s%s %s%srejected %s%s",
3179 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3180 host_and_ident(TRUE),
3183 rc == FAIL ? US"" : US"temporarily ",
3187 if (!drop) return 0;
3189 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3190 smtp_get_connection_info());
3192 /* Run the not-quit ACL, but without any custom messages. This should not be a
3193 problem, because we get here only if some other ACL has issued "drop", and
3194 in that case, *its* custom messages will have been used above. */
3196 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3203 /*************************************************
3204 * Handle SMTP exit when QUIT is not given *
3205 *************************************************/
3207 /* This function provides a logging/statistics hook for when an SMTP connection
3208 is dropped on the floor or the other end goes away. It's a global function
3209 because it's called from receive.c as well as this module. As well as running
3210 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3211 response, either with a custom message from the ACL, or using a default. There
3212 is one case, however, when no message is output - after "drop". In that case,
3213 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3214 passed to this function.
3216 In case things go wrong while processing this function, causing an error that
3217 may re-enter this function, there is a recursion check.
3220 reason What $smtp_notquit_reason will be set to in the ACL;
3221 if NULL, the ACL is not run
3222 code The error code to return as part of the response
3223 defaultrespond The default message if there's no user_msg
3229 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3232 uschar *user_msg = NULL;
3233 uschar *log_msg = NULL;
3235 /* Check for recursive acll */
3237 if (smtp_exit_function_called)
3239 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3243 smtp_exit_function_called = TRUE;
3245 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3247 if (acl_smtp_notquit && reason)
3249 smtp_notquit_reason = reason;
3250 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3251 &log_msg)) == ERROR)
3252 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3256 /* Write an SMTP response if we are expected to give one. As the default
3257 responses are all internal, they should always fit in the buffer, but code a
3258 warning, just in case. Note that string_vformat() still leaves a complete
3259 string, even if it is incomplete. */
3261 if (code && defaultrespond)
3264 smtp_respond(code, 3, TRUE, user_msg);
3269 va_start(ap, defaultrespond);
3270 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3271 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3272 smtp_printf("%s %s\r\n", code, buffer);
3282 /*************************************************
3283 * Verify HELO argument *
3284 *************************************************/
3286 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3287 matched. It is also called from ACL processing if verify = helo is used and
3288 verification was not previously tried (i.e. helo_try_verify_hosts was not
3289 matched). The result of its processing is to set helo_verified and
3290 helo_verify_failed. These variables should both be FALSE for this function to
3293 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3294 for IPv6 ::ffff: literals.
3297 Returns: TRUE if testing was completed;
3298 FALSE on a temporary failure
3302 smtp_verify_helo(void)
3306 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3309 if (sender_helo_name == NULL)
3311 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3314 /* Deal with the case of -bs without an IP address */
3316 else if (sender_host_address == NULL)
3318 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3319 helo_verified = TRUE;
3322 /* Deal with the more common case when there is a sending IP address */
3324 else if (sender_helo_name[0] == '[')
3326 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3327 Ustrlen(sender_host_address)) == 0;
3332 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3333 helo_verified = Ustrncmp(sender_helo_name + 1,
3334 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3339 { if (helo_verified) debug_printf("matched host address\n"); }
3342 /* Do a reverse lookup if one hasn't already given a positive or negative
3343 response. If that fails, or the name doesn't match, try checking with a forward
3348 if (sender_host_name == NULL && !host_lookup_failed)
3349 yield = host_name_lookup() != DEFER;
3351 /* If a host name is known, check it and all its aliases. */
3353 if (sender_host_name)
3354 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3356 sender_helo_dnssec = sender_host_dnssec;
3357 HDEBUG(D_receive) debug_printf("matched host name\n");
3361 uschar **aliases = sender_host_aliases;
3363 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3365 sender_helo_dnssec = sender_host_dnssec;
3369 HDEBUG(D_receive) if (helo_verified)
3370 debug_printf("matched alias %s\n", *(--aliases));
3373 /* Final attempt: try a forward lookup of the helo name */
3382 h.name = sender_helo_name;
3389 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3391 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3392 NULL, NULL, NULL, &d, NULL, NULL);
3393 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3394 for (hh = &h; hh; hh = hh->next)
3395 if (Ustrcmp(hh->address, sender_host_address) == 0)
3397 helo_verified = TRUE;
3398 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3401 debug_printf("IP address for %s matches calling address\n"
3402 "Forward DNS security status: %sverified\n",
3403 sender_helo_name, sender_helo_dnssec ? "" : "un");
3410 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3417 /*************************************************
3418 * Send user response message *
3419 *************************************************/
3421 /* This function is passed a default response code and a user message. It calls
3422 smtp_message_code() to check and possibly modify the response code, and then
3423 calls smtp_respond() to transmit the response. I put this into a function
3424 just to avoid a lot of repetition.
3427 code the response code
3428 user_msg the user message
3434 smtp_user_msg(uschar *code, uschar *user_msg)
3437 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3438 smtp_respond(code, len, TRUE, user_msg);
3444 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3446 const uschar *set_id = NULL;
3449 /* Run the checking code, passing the remainder of the command line as
3450 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3451 it as the only set numerical variable. The authenticator may set $auth<n>
3452 and also set other numeric variables. The $auth<n> variables are preferred
3453 nowadays; the numerical variables remain for backwards compatibility.
3455 Afterwards, have a go at expanding the set_id string, even if
3456 authentication failed - for bad passwords it can be useful to log the
3457 userid. On success, require set_id to expand and exist, and put it in
3458 authenticated_id. Save this in permanent store, as the working store gets
3459 reset at HELO, RSET, etc. */
3461 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3463 expand_nlength[0] = 0; /* $0 contains nothing */
3465 rc = (au->info->servercode)(au, smtp_cmd_data);
3466 if (au->set_id) set_id = expand_string(au->set_id);
3467 expand_nmax = -1; /* Reset numeric variables */
3468 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3470 /* The value of authenticated_id is stored in the spool file and printed in
3471 log lines. It must not contain binary zeros or newline characters. In
3472 normal use, it never will, but when playing around or testing, this error
3473 can (did) happen. To guard against this, ensure that the id contains only
3474 printing characters. */
3476 if (set_id) set_id = string_printing(set_id);
3478 /* For the non-OK cases, set up additional logging data if set_id
3482 set_id = set_id && *set_id
3483 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3485 /* Switch on the result */
3490 if (!au->set_id || set_id) /* Complete success */
3492 if (set_id) authenticated_id = string_copy_malloc(set_id);
3493 sender_host_authenticated = au->name;
3494 authentication_failed = FALSE;
3495 authenticated_fail_id = NULL; /* Impossible to already be set? */
3498 (sender_host_address ? protocols : protocols_local)
3499 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3500 *s = *ss = US"235 Authentication succeeded";
3501 authenticated_by = au;
3505 /* Authentication succeeded, but we failed to expand the set_id string.
3506 Treat this as a temporary error. */
3508 auth_defer_msg = expand_string_message;
3512 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3513 *s = string_sprintf("435 Unable to authenticate at present%s",
3514 auth_defer_user_msg);
3515 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3516 set_id, auth_defer_msg);
3520 *s = *ss = US"501 Invalid base64 data";
3524 *s = *ss = US"501 Authentication cancelled";
3528 *s = *ss = US"553 Initial data not expected";
3532 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3533 *s = US"535 Incorrect authentication data";
3534 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3538 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3539 *s = US"435 Internal error";
3540 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3541 "check", set_id, rc);
3553 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3556 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3558 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3560 rd = Ustrlen(recipient) + 1;
3561 *recipient = rewrite_address_qualify(*recipient, TRUE);
3564 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3566 log_write(L_smtp_syntax_error,
3567 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3568 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3576 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3579 incomplete_transaction_log(US"QUIT");
3582 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3584 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3588 smtp_respond(US"221", 3, TRUE, *user_msgp);
3590 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3593 tls_close(TRUE, TRUE);
3596 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3597 smtp_get_connection_info());
3602 smtp_rset_handler(void)
3605 incomplete_transaction_log(US"RSET");
3606 smtp_printf("250 Reset OK\r\n");
3607 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3612 /*************************************************
3613 * Initialize for SMTP incoming message *
3614 *************************************************/
3616 /* This function conducts the initial dialogue at the start of an incoming SMTP
3617 message, and builds a list of recipients. However, if the incoming message
3618 is part of a batch (-bS option) a separate function is called since it would
3619 be messy having tests splattered about all over this function. This function
3620 therefore handles the case where interaction is occurring. The input and output
3621 files are set up in smtp_in and smtp_out.
3623 The global recipients_list is set to point to a vector of recipient_item
3624 blocks, whose number is given by recipients_count. This is extended by the
3625 receive_add_recipient() function. The global variable sender_address is set to
3626 the sender's address. The yield is +1 if a message has been successfully
3627 started, 0 if a QUIT command was encountered or the connection was refused from
3628 the particular host, or -1 if the connection was lost.
3632 Returns: > 0 message successfully started (reached DATA)
3633 = 0 QUIT read or end of file reached or call refused
3638 smtp_setup_msg(void)
3641 BOOL toomany = FALSE;
3642 BOOL discarded = FALSE;
3643 BOOL last_was_rej_mail = FALSE;
3644 BOOL last_was_rcpt = FALSE;
3645 void *reset_point = store_get(0);
3647 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3649 /* Reset for start of new message. We allow one RSET not to be counted as a
3650 nonmail command, for those MTAs that insist on sending it between every
3651 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3652 TLS between messages (an Exim client may do this if it has messages queued up
3653 for the host). Note: we do NOT reset AUTH at this point. */
3655 smtp_reset(reset_point);
3656 message_ended = END_NOTSTARTED;
3658 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3660 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3661 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3662 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3664 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3665 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3668 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3670 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3672 /* Batched SMTP is handled in a different function. */
3674 if (smtp_batched_input) return smtp_setup_batch_msg();
3676 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3677 value. The values are 2 larger than the required yield of the function. */
3681 const uschar **argv;
3682 uschar *etrn_command;
3683 uschar *etrn_serialize_key;
3685 uschar *log_msg, *smtp_code;
3686 uschar *user_msg = NULL;
3687 uschar *recipient = NULL;
3688 uschar *hello = NULL;
3690 BOOL was_rej_mail = FALSE;
3691 BOOL was_rcpt = FALSE;
3692 void (*oldsignal)(int);
3694 int start, end, sender_domain, recipient_domain;
3698 uschar *orcpt = NULL;
3702 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3703 if ( tls_in.active >= 0
3705 && tls_in.certificate_verified
3706 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3709 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3711 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3712 &user_msg, &log_msg)) != OK
3715 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3719 for (au = auths; au; au = au->next)
3720 if (strcmpic(US"tls", au->driver_name) == 0)
3722 smtp_cmd_data = NULL;
3724 if (smtp_in_auth(au, &s, &ss) == OK)
3725 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3727 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3734 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3735 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3736 US &off, sizeof(off));
3739 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3741 /* The AUTH command is not permitted to occur inside a transaction, and may
3742 occur successfully only once per connection. Actually, that isn't quite
3743 true. When TLS is started, all previous information about a connection must
3744 be discarded, so a new AUTH is permitted at that time.
3746 AUTH may only be used when it has been advertised. However, it seems that
3747 there are clients that send AUTH when it hasn't been advertised, some of
3748 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3749 So there's a get-out that allows this to happen.
3751 AUTH is initially labelled as a "nonmail command" so that one occurrence
3752 doesn't get counted. We change the label here so that multiple failing
3753 AUTHS will eventually hit the nonmail threshold. */
3757 authentication_failed = TRUE;
3758 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3760 if (!auth_advertised && !allow_auth_unadvertised)
3762 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3763 US"AUTH command used when not advertised");
3766 if (sender_host_authenticated)
3768 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3769 US"already authenticated");
3774 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3775 US"not permitted in mail transaction");
3782 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3783 &user_msg, &log_msg)) != OK
3786 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3790 /* Find the name of the requested authentication mechanism. */
3793 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3795 if (!isalnum(c) && c != '-' && c != '_')
3797 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3798 US"invalid character in authentication mechanism name");
3804 /* If not at the end of the line, we must be at white space. Terminate the
3805 name and move the pointer on to any data that may be present. */
3807 if (*smtp_cmd_data != 0)
3809 *smtp_cmd_data++ = 0;
3810 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3813 /* Search for an authentication mechanism which is configured for use
3814 as a server and which has been advertised (unless, sigh, allow_auth_
3815 unadvertised is set). */
3817 for (au = auths; au; au = au->next)
3818 if (strcmpic(s, au->public_name) == 0 && au->server &&
3819 (au->advertised || allow_auth_unadvertised))
3824 c = smtp_in_auth(au, &s, &ss);
3826 smtp_printf("%s\r\n", s);
3828 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3829 au->name, host_and_ident(FALSE), ss);
3832 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3833 string_sprintf("%s authentication mechanism not supported", s));
3835 break; /* AUTH_CMD */
3837 /* The HELO/EHLO commands are permitted to appear in the middle of a
3838 session as well as at the beginning. They have the effect of a reset in
3839 addition to their other functions. Their absence at the start cannot be
3840 taken to be an error.
3844 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3845 or 502 failure replies MUST be returned as appropriate. The SMTP
3846 server MUST stay in the same state after transmitting these replies
3847 that it was in before the EHLO was received.
3849 Therefore, we do not do the reset until after checking the command for
3850 acceptability. This change was made for Exim release 4.11. Previously
3851 it did the reset first. */
3864 HELO_EHLO: /* Common code for HELO and EHLO */
3865 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3866 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3868 /* Reject the HELO if its argument was invalid or non-existent. A
3869 successful check causes the argument to be saved in malloc store. */
3871 if (!check_helo(smtp_cmd_data))
3873 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3875 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3876 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3877 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3878 string_printing(smtp_cmd_argument));
3880 if (++synprot_error_count > smtp_max_synprot_errors)
3882 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3883 "syntax or protocol errors (last command was \"%s\")",
3884 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3891 /* If sender_host_unknown is true, we have got here via the -bs interface,
3892 not called from inetd. Otherwise, we are running an IP connection and the
3893 host address will be set. If the helo name is the primary name of this
3894 host and we haven't done a reverse lookup, force one now. If helo_required
3895 is set, ensure that the HELO name matches the actual host. If helo_verify
3896 is set, do the same check, but softly. */
3898 if (!sender_host_unknown)
3900 BOOL old_helo_verified = helo_verified;
3901 uschar *p = smtp_cmd_data;
3903 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3906 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3907 because otherwise the log can be confusing. */
3909 if (sender_host_name == NULL &&
3910 (deliver_domain = sender_helo_name, /* set $domain */
3911 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3912 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3913 (void)host_name_lookup();
3915 /* Rebuild the fullhost info to include the HELO name (and the real name
3916 if it was looked up.) */
3918 host_build_sender_fullhost(); /* Rebuild */
3919 set_process_info("handling%s incoming connection from %s",
3920 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3922 /* Verify if configured. This doesn't give much security, but it does
3923 make some people happy to be able to do it. If helo_required is set,
3924 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3925 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3926 now obsolescent, since the verification can now be requested selectively
3929 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3930 if (helo_required || helo_verify)
3932 BOOL tempfail = !smtp_verify_helo();
3937 smtp_printf("%d %s argument does not match calling host\r\n",
3938 tempfail? 451 : 550, hello);
3939 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3940 tempfail? "temporarily " : "",
3941 hello, sender_helo_name, host_and_ident(FALSE));
3942 helo_verified = old_helo_verified;
3943 break; /* End of HELO/EHLO processing */
3945 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3946 "helo_try_verify_hosts\n", hello);
3951 #ifdef EXPERIMENTAL_SPF
3952 /* set up SPF context */
3953 spf_init(sender_helo_name, sender_host_address);
3956 /* Apply an ACL check if one is defined; afterwards, recheck
3957 synchronization in case the client started sending in a delay. */
3960 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3961 &user_msg, &log_msg)) != OK)
3963 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3964 sender_helo_name = NULL;
3965 host_build_sender_fullhost(); /* Rebuild */
3968 else if (!check_sync()) goto SYNC_FAILURE;
3970 /* Generate an OK reply. The default string includes the ident if present,
3971 and also the IP address if present. Reflecting back the ident is intended
3972 as a deterrent to mail forgers. For maximum efficiency, and also because
3973 some broken systems expect each response to be in a single packet, arrange
3974 that the entire reply is sent in one write(). */
3976 auth_advertised = FALSE;
3977 pipelining_advertised = FALSE;
3979 tls_advertised = FALSE;
3981 dsn_advertised = FALSE;
3983 smtputf8_advertised = FALSE;
3986 smtp_code = US"250 "; /* Default response code plus space*/
3987 if (user_msg == NULL)
3989 s = string_sprintf("%.3s %s Hello %s%s%s",
3991 smtp_active_hostname,
3992 (sender_ident == NULL)? US"" : sender_ident,
3993 (sender_ident == NULL)? US"" : US" at ",
3994 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3999 if (sender_host_address != NULL)
4001 s = string_catn(s, &size, &ptr, US" [", 2);
4002 s = string_cat (s, &size, &ptr, sender_host_address);
4003 s = string_catn(s, &size, &ptr, US"]", 1);
4007 /* A user-supplied EHLO greeting may not contain more than one line. Note
4008 that the code returned by smtp_message_code() includes the terminating
4009 whitespace character. */
4015 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4016 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4017 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4019 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4020 "newlines: message truncated: %s", string_printing(s));
4027 s = string_catn(s, &size, &ptr, US"\r\n", 2);
4029 /* If we received EHLO, we must create a multiline response which includes
4030 the functions supported. */
4036 /* I'm not entirely happy with this, as an MTA is supposed to check
4037 that it has enough room to accept a message of maximum size before
4038 it sends this. However, there seems little point in not sending it.
4039 The actual size check happens later at MAIL FROM time. By postponing it
4040 till then, VRFY and EXPN can be used after EHLO when space is short. */
4042 if (thismessage_size_limit > 0)
4044 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4045 thismessage_size_limit);
4046 s = string_cat(s, &size, &ptr, big_buffer);
4050 s = string_catn(s, &size, &ptr, smtp_code, 3);
4051 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
4054 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4055 clean; if it has an 8-bit character in its hand, it just sends it. It
4056 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4057 However, some users want this option simply in order to stop MUAs
4058 mangling messages that contain top-bit-set characters. It is therefore
4059 provided as an option. */
4061 if (accept_8bitmime)
4063 s = string_catn(s, &size, &ptr, smtp_code, 3);
4064 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
4067 /* Advertise DSN support if configured to do so. */
4068 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4070 s = string_catn(s, &size, &ptr, smtp_code, 3);
4071 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
4072 dsn_advertised = TRUE;
4075 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4076 permitted to issue them; a check is made when any host actually tries. */
4080 s = string_catn(s, &size, &ptr, smtp_code, 3);
4081 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
4085 s = string_catn(s, &size, &ptr, smtp_code, 3);
4086 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
4090 s = string_catn(s, &size, &ptr, smtp_code, 3);
4091 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
4094 /* Exim is quite happy with pipelining, so let the other end know that
4095 it is safe to use it, unless advertising is disabled. */
4097 if (pipelining_enable &&
4098 verify_check_host(&pipelining_advertise_hosts) == OK)
4100 s = string_catn(s, &size, &ptr, smtp_code, 3);
4101 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
4102 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4103 pipelining_advertised = TRUE;
4107 /* If any server authentication mechanisms are configured, advertise
4108 them if the current host is in auth_advertise_hosts. The problem with
4109 advertising always is that some clients then require users to
4110 authenticate (and aren't configurable otherwise) even though it may not
4111 be necessary (e.g. if the host is in host_accept_relay).
4113 RFC 2222 states that SASL mechanism names contain only upper case
4114 letters, so output the names in upper case, though we actually recognize
4115 them in either case in the AUTH command. */
4119 && !sender_host_authenticated
4121 && verify_check_host(&auth_advertise_hosts) == OK
4126 for (au = auths; au; au = au->next)
4127 if (au->server && (au->advertise_condition == NULL ||
4128 expand_check_condition(au->advertise_condition, au->name,
4129 US"authenticator")))
4134 s = string_catn(s, &size, &ptr, smtp_code, 3);
4135 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
4137 auth_advertised = TRUE;
4140 s = string_catn(s, &size, &ptr, US" ", 1);
4141 s = string_cat (s, &size, &ptr, au->public_name);
4142 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
4143 au->advertised = TRUE;
4146 au->advertised = FALSE;
4148 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4151 /* RFC 3030 CHUNKING */
4153 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4155 s = string_catn(s, &size, &ptr, smtp_code, 3);
4156 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4157 chunking_offered = TRUE;
4158 chunking_state = CHUNKING_OFFERED;
4161 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4162 if it has been included in the binary, and the host matches
4163 tls_advertise_hosts. We must *not* advertise if we are already in a
4164 secure connection. */
4167 if (tls_in.active < 0 &&
4168 verify_check_host(&tls_advertise_hosts) != FAIL)
4170 s = string_catn(s, &size, &ptr, smtp_code, 3);
4171 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4172 tls_advertised = TRUE;
4176 #ifndef DISABLE_PRDR
4177 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4180 s = string_catn(s, &size, &ptr, smtp_code, 3);
4181 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4186 if ( accept_8bitmime
4187 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4189 s = string_catn(s, &size, &ptr, smtp_code, 3);
4190 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4191 smtputf8_advertised = TRUE;
4195 /* Finish off the multiline reply with one that is always available. */
4197 s = string_catn(s, &size, &ptr, smtp_code, 3);
4198 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4201 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4207 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4211 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4216 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4217 memmove(cr, cr + 1, (ptr--) - (cr - s));
4218 debug_printf("SMTP>> %s", s);
4222 /* Reset the protocol and the state, abandoning any previous message. */
4224 (sender_host_address ? protocols : protocols_local)
4226 ? pextend + (sender_host_authenticated ? pauthed : 0)
4228 + (tls_in.active >= 0 ? pcrpted : 0)
4230 smtp_reset(reset_point);
4232 break; /* HELO/EHLO */
4235 /* The MAIL command requires an address as an operand. All we do
4236 here is to parse it for syntactic correctness. The form "<>" is
4237 a special case which converts into an empty string. The start/end
4238 pointers in the original are not used further for this address, as
4239 it is the canonical extracted address which is all that is kept. */
4243 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4244 was_rej_mail = TRUE; /* Reset if accepted */
4245 env_mail_type_t * mail_args; /* Sanity check & validate args */
4247 if (helo_required && !helo_seen)
4249 smtp_printf("503 HELO or EHLO required\r\n");
4250 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4251 "HELO/EHLO given", host_and_ident(FALSE));
4255 if (sender_address != NULL)
4257 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4258 US"sender already given");
4262 if (smtp_cmd_data[0] == 0)
4264 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4265 US"MAIL must have an address operand");
4269 /* Check to see if the limit for messages per connection would be
4270 exceeded by accepting further messages. */
4272 if (smtp_accept_max_per_connection > 0 &&
4273 smtp_mailcmd_count > smtp_accept_max_per_connection)
4275 smtp_printf("421 too many messages in this connection\r\n");
4276 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4277 "messages in one connection", host_and_ident(TRUE));
4281 /* Reset for start of message - even if this is going to fail, we
4282 obviously need to throw away any previous data. */
4284 smtp_reset(reset_point);
4286 sender_data = recipient_data = NULL;
4288 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4292 uschar *name, *value, *end;
4293 unsigned long int size;
4294 BOOL arg_error = FALSE;
4296 if (!extract_option(&name, &value)) break;
4298 for (mail_args = env_mail_type_list;
4299 mail_args->value != ENV_MAIL_OPT_NULL;
4302 if (strcmpic(name, mail_args->name) == 0)
4304 if (mail_args->need_value && strcmpic(value, US"") == 0)
4307 switch(mail_args->value)
4309 /* Handle SIZE= by reading the value. We don't do the check till later,
4310 in order to be able to log the sender address on failure. */
4311 case ENV_MAIL_OPT_SIZE:
4312 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4314 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4316 message_size = (int)size;
4322 /* If this session was initiated with EHLO and accept_8bitmime is set,
4323 Exim will have indicated that it supports the BODY=8BITMIME option. In
4324 fact, it does not support this according to the RFCs, in that it does not
4325 take any special action for forwarding messages containing 8-bit
4326 characters. That is why accept_8bitmime is not the default setting, but
4327 some sites want the action that is provided. We recognize both "8BITMIME"
4328 and "7BIT" as body types, but take no action. */
4329 case ENV_MAIL_OPT_BODY:
4330 if (accept_8bitmime) {
4331 if (strcmpic(value, US"8BITMIME") == 0)
4333 else if (strcmpic(value, US"7BIT") == 0)
4338 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4339 US"invalid data for BODY");
4342 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4348 /* Handle the two DSN options, but only if configured to do so (which
4349 will have caused "DSN" to be given in the EHLO response). The code itself
4350 is included only if configured in at build time. */
4352 case ENV_MAIL_OPT_RET:
4355 /* Check if RET has already been set */
4358 synprot_error(L_smtp_syntax_error, 501, NULL,
4359 US"RET can be specified once only");
4362 dsn_ret = strcmpic(value, US"HDRS") == 0
4364 : strcmpic(value, US"FULL") == 0
4367 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4368 /* Check for invalid invalid value, and exit with error */
4371 synprot_error(L_smtp_syntax_error, 501, NULL,
4372 US"Value for RET is invalid");
4377 case ENV_MAIL_OPT_ENVID:
4380 /* Check if the dsn envid has been already set */
4381 if (dsn_envid != NULL)
4383 synprot_error(L_smtp_syntax_error, 501, NULL,
4384 US"ENVID can be specified once only");
4387 dsn_envid = string_copy(value);
4388 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4392 /* Handle the AUTH extension. If the value given is not "<>" and either
4393 the ACL says "yes" or there is no ACL but the sending host is
4394 authenticated, we set it up as the authenticated sender. However, if the
4395 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4396 the condition is met. The value of AUTH is an xtext, which means that +,
4397 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4399 case ENV_MAIL_OPT_AUTH:
4400 if (Ustrcmp(value, "<>") != 0)
4405 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4407 /* Put back terminator overrides for error message */
4410 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4411 US"invalid data for AUTH");
4414 if (acl_smtp_mailauth == NULL)
4416 ignore_msg = US"client not authenticated";
4417 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4421 ignore_msg = US"rejected by ACL";
4422 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4423 &user_msg, &log_msg);
4429 if (authenticated_by == NULL ||
4430 authenticated_by->mail_auth_condition == NULL ||
4431 expand_check_condition(authenticated_by->mail_auth_condition,
4432 authenticated_by->name, US"authenticator"))
4433 break; /* Accept the AUTH */
4435 ignore_msg = US"server_mail_auth_condition failed";
4436 if (authenticated_id != NULL)
4437 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4438 ignore_msg, authenticated_id);
4443 authenticated_sender = NULL;
4444 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4445 value, host_and_ident(TRUE), ignore_msg);
4448 /* Should only get DEFER or ERROR here. Put back terminator
4449 overrides for error message */
4454 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4461 #ifndef DISABLE_PRDR
4462 case ENV_MAIL_OPT_PRDR:
4464 prdr_requested = TRUE;
4469 case ENV_MAIL_OPT_UTF8:
4470 if (smtputf8_advertised)
4472 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4473 message_smtputf8 = allow_utf8_domains = TRUE;
4474 received_protocol = string_sprintf("utf8%s", received_protocol);
4478 /* No valid option. Stick back the terminator characters and break
4479 the loop. Do the name-terminator second as extract_option sets
4480 value==name when it found no equal-sign.
4481 An error for a malformed address will occur. */
4482 case ENV_MAIL_OPT_NULL:
4490 /* Break out of for loop if switch() had bad argument or
4491 when start of the email address is reached */
4492 if (arg_error) break;
4495 /* If we have passed the threshold for rate limiting, apply the current
4496 delay, and update it for next time, provided this is a limited host. */
4498 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4499 verify_check_host(&smtp_ratelimit_hosts) == OK)
4501 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4502 smtp_delay_mail/1000.0);
4503 millisleep((int)smtp_delay_mail);
4504 smtp_delay_mail *= smtp_rlm_factor;
4505 if (smtp_delay_mail > (double)smtp_rlm_limit)
4506 smtp_delay_mail = (double)smtp_rlm_limit;
4509 /* Now extract the address, first applying any SMTP-time rewriting. The
4510 TRUE flag allows "<>" as a sender address. */
4512 raw_sender = rewrite_existflags & rewrite_smtp
4513 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4514 global_rewrite_rules)
4518 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4523 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4527 sender_address = raw_sender;
4529 /* If there is a configured size limit for mail, check that this message
4530 doesn't exceed it. The check is postponed to this point so that the sender
4533 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4535 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4536 log_write(L_size_reject,
4537 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4538 "message too big: size%s=%d max=%d",
4540 host_and_ident(TRUE),
4541 (message_size == INT_MAX)? ">" : "",
4543 thismessage_size_limit);
4544 sender_address = NULL;
4548 /* Check there is enough space on the disk unless configured not to.
4549 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4550 plus the current message - i.e. we accept the message only if it won't
4551 reduce the space below the threshold. Add 5000 to the size to allow for
4552 overheads such as the Received: line and storing of recipients, etc.
4553 By putting the check here, even when SIZE is not given, it allow VRFY
4554 and EXPN etc. to be used when space is short. */
4556 if (!receive_check_fs(
4557 (smtp_check_spool_space && message_size >= 0)?
4558 message_size + 5000 : 0))
4560 smtp_printf("452 Space shortage, please try later\r\n");
4561 sender_address = NULL;
4565 /* If sender_address is unqualified, reject it, unless this is a locally
4566 generated message, or the sending host or net is permitted to send
4567 unqualified addresses - typically local machines behaving as MUAs -
4568 in which case just qualify the address. The flag is set above at the start
4569 of the SMTP connection. */
4571 if (sender_domain == 0 && sender_address[0] != 0)
4573 if (allow_unqualified_sender)
4575 sender_domain = Ustrlen(sender_address) + 1;
4576 sender_address = rewrite_address_qualify(sender_address, FALSE);
4577 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4582 smtp_printf("501 %s: sender address must contain a domain\r\n",
4584 log_write(L_smtp_syntax_error,
4585 LOG_MAIN|LOG_REJECT,
4586 "unqualified sender rejected: <%s> %s%s",
4588 host_and_ident(TRUE),
4590 sender_address = NULL;
4595 /* Apply an ACL check if one is defined, before responding. Afterwards,
4596 when pipelining is not advertised, do another sync check in case the ACL
4597 delayed and the client started sending in the meantime. */
4601 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4602 if (rc == OK && !pipelining_advertised && !check_sync())
4608 if (rc == OK || rc == DISCARD)
4611 smtp_printf("%s%s%s", US"250 OK",
4612 #ifndef DISABLE_PRDR
4613 prdr_requested ? US", PRDR Requested" : US"",
4620 #ifndef DISABLE_PRDR
4622 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4624 smtp_user_msg(US"250", user_msg);
4626 smtp_delay_rcpt = smtp_rlr_base;
4627 recipients_discarded = (rc == DISCARD);
4628 was_rej_mail = FALSE;
4632 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4633 sender_address = NULL;
4638 /* The RCPT command requires an address as an operand. There may be any
4639 number of RCPT commands, specifying multiple recipients. We build them all
4640 into a data structure. The start/end values given by parse_extract_address
4641 are not used, as we keep only the extracted address. */
4646 was_rcpt = rcpt_in_progress = TRUE;
4648 /* There must be a sender address; if the sender was rejected and
4649 pipelining was advertised, we assume the client was pipelining, and do not
4650 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4651 get the same treatment. */
4653 if (sender_address == NULL)
4655 if (pipelining_advertised && last_was_rej_mail)
4657 smtp_printf("503 sender not yet given\r\n");
4658 was_rej_mail = TRUE;
4662 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4663 US"sender not yet given");
4664 was_rcpt = FALSE; /* Not a valid RCPT */
4670 /* Check for an operand */
4672 if (smtp_cmd_data[0] == 0)
4674 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4675 US"RCPT must have an address operand");
4680 /* Set the DSN flags orcpt and dsn_flags from the session*/
4686 uschar *name, *value;
4688 if (!extract_option(&name, &value))
4691 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4693 /* Check whether orcpt has been already set */
4696 synprot_error(L_smtp_syntax_error, 501, NULL,
4697 US"ORCPT can be specified once only");
4700 orcpt = string_copy(value);
4701 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4704 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4706 /* Check if the notify flags have been already set */
4709 synprot_error(L_smtp_syntax_error, 501, NULL,
4710 US"NOTIFY can be specified once only");
4713 if (strcmpic(value, US"NEVER") == 0)
4714 flags |= rf_notify_never;
4721 while (*pp != 0 && *pp != ',') pp++;
4722 if (*pp == ',') *pp++ = 0;
4723 if (strcmpic(p, US"SUCCESS") == 0)
4725 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4726 flags |= rf_notify_success;
4728 else if (strcmpic(p, US"FAILURE") == 0)
4730 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4731 flags |= rf_notify_failure;
4733 else if (strcmpic(p, US"DELAY") == 0)
4735 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4736 flags |= rf_notify_delay;
4740 /* Catch any strange values */
4741 synprot_error(L_smtp_syntax_error, 501, NULL,
4742 US"Invalid value for NOTIFY parameter");
4747 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4751 /* Unknown option. Stick back the terminator characters and break
4752 the loop. An error for a malformed address will occur. */
4756 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4763 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4764 as a recipient address */
4766 recipient = rewrite_existflags & rewrite_smtp
4767 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4768 global_rewrite_rules)
4771 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4772 &recipient_domain, FALSE)))
4774 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4779 /* If the recipient address is unqualified, reject it, unless this is a
4780 locally generated message. However, unqualified addresses are permitted
4781 from a configured list of hosts and nets - typically when behaving as
4782 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4783 really. The flag is set at the start of the SMTP connection.
4785 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4786 assumed this meant "reserved local part", but the revision of RFC 821 and
4787 friends now makes it absolutely clear that it means *mailbox*. Consequently
4788 we must always qualify this address, regardless. */
4790 if (!recipient_domain)
4791 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4798 /* Check maximum allowed */
4800 if (rcpt_count > recipients_max && recipients_max > 0)
4802 if (recipients_max_reject)
4805 smtp_printf("552 too many recipients\r\n");
4807 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4808 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4813 smtp_printf("452 too many recipients\r\n");
4815 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4816 "temporarily rejected: sender=<%s> %s", sender_address,
4817 host_and_ident(TRUE));
4824 /* If we have passed the threshold for rate limiting, apply the current
4825 delay, and update it for next time, provided this is a limited host. */
4827 if (rcpt_count > smtp_rlr_threshold &&
4828 verify_check_host(&smtp_ratelimit_hosts) == OK)
4830 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4831 smtp_delay_rcpt/1000.0);
4832 millisleep((int)smtp_delay_rcpt);
4833 smtp_delay_rcpt *= smtp_rlr_factor;
4834 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4835 smtp_delay_rcpt = (double)smtp_rlr_limit;
4838 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4839 for them. Otherwise, check the access control list for this recipient. As
4840 there may be a delay in this, re-check for a synchronization error
4841 afterwards, unless pipelining was advertised. */
4843 if (recipients_discarded)
4846 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4848 && !pipelining_advertised && !check_sync())
4851 /* The ACL was happy */
4856 smtp_user_msg(US"250", user_msg);
4858 smtp_printf("250 Accepted\r\n");
4859 receive_add_recipient(recipient, -1);
4861 /* Set the dsn flags in the recipients_list */
4862 recipients_list[recipients_count-1].orcpt = orcpt;
4863 recipients_list[recipients_count-1].dsn_flags = flags;
4865 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4866 recipients_list[recipients_count-1].orcpt,
4867 recipients_list[recipients_count-1].dsn_flags);
4870 /* The recipient was discarded */
4872 else if (rc == DISCARD)
4875 smtp_user_msg(US"250", user_msg);
4877 smtp_printf("250 Accepted\r\n");
4880 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4881 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4882 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4883 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4884 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4887 /* Either the ACL failed the address, or it was deferred. */
4891 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4892 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4897 /* The DATA command is legal only if it follows successful MAIL FROM
4898 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4899 not counted as a protocol error if it follows RCPT (which must have been
4900 rejected if there are no recipients.) This function is complete when a
4901 valid DATA command is encountered.
4903 Note concerning the code used: RFC 2821 says this:
4905 - If there was no MAIL, or no RCPT, command, or all such commands
4906 were rejected, the server MAY return a "command out of sequence"
4907 (503) or "no valid recipients" (554) reply in response to the
4910 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4911 because it is the same whether pipelining is in use or not.
4913 If all the RCPT commands that precede DATA provoked the same error message
4914 (often indicating some kind of system error), it is helpful to include it
4915 with the DATA rejection (an idea suggested by Tony Finch). */
4922 if (chunking_state != CHUNKING_OFFERED)
4924 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4925 US"BDAT command used when CHUNKING not advertised");
4929 /* grab size, endmarker */
4931 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
4933 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4934 US"missing size for BDAT command");
4937 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
4938 ? CHUNKING_LAST : CHUNKING_ACTIVE;
4939 chunking_data_left = chunking_datasize;
4940 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
4941 (int)chunking_state, chunking_data_left);
4943 lwr_receive_getc = receive_getc;
4944 lwr_receive_ungetc = receive_ungetc;
4945 receive_getc = bdat_getc;
4946 receive_ungetc = bdat_ungetc;
4954 DATA_BDAT: /* Common code for DATA and BDAT */
4955 if (!discarded && recipients_count <= 0)
4957 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4959 uschar *code = US"503";
4960 int len = Ustrlen(rcpt_smtp_response);
4961 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4963 /* Responses from smtp_printf() will have \r\n on the end */
4964 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4965 rcpt_smtp_response[len-2] = 0;
4966 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4968 if (pipelining_advertised && last_was_rcpt)
4969 smtp_printf("503 Valid RCPT command must precede %s\r\n",
4970 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
4972 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4973 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
4974 ? US"valid RCPT command must precede DATA"
4975 : US"valid RCPT command must precede BDAT");
4977 if (chunking_state > CHUNKING_OFFERED)
4982 if (toomany && recipients_max_reject)
4984 sender_address = NULL; /* This will allow a new MAIL without RSET */
4985 sender_address_unrewritten = NULL;
4986 smtp_printf("554 Too many recipients\r\n");
4990 if (chunking_state > CHUNKING_OFFERED)
4991 rc = OK; /* No predata ACL or go-ahead output for BDAT */
4994 /* If there is an ACL, re-check the synchronization afterwards, since the
4995 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4996 to get the DATA command sent. */
4998 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5002 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5003 enable_dollar_recipients = TRUE;
5004 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5006 enable_dollar_recipients = FALSE;
5007 if (rc == OK && !check_sync())
5011 { /* Either the ACL failed the address, or it was deferred. */
5012 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5018 smtp_user_msg(US"354", user_msg);
5021 "354 Enter message, ending with \".\" on a line by itself\r\n");
5025 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5026 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5027 US &on, sizeof(on));
5030 message_ended = END_NOTENDED; /* Indicate in middle of data */
5041 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5042 &start, &end, &recipient_domain, FALSE)))
5044 smtp_printf("501 %s\r\n", errmess);
5048 if (!recipient_domain)
5049 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5053 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5054 &user_msg, &log_msg)) != OK)
5055 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5059 address_item * addr = deliver_make_addr(address, FALSE);
5061 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5062 -1, -1, NULL, NULL, NULL))
5065 s = string_sprintf("250 <%s> is deliverable", address);
5069 s = (addr->user_message != NULL)?
5070 string_sprintf("451 <%s> %s", address, addr->user_message) :
5071 string_sprintf("451 Cannot resolve <%s> at this time", address);
5075 s = (addr->user_message != NULL)?
5076 string_sprintf("550 <%s> %s", address, addr->user_message) :
5077 string_sprintf("550 <%s> is not deliverable", address);
5078 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5079 smtp_cmd_argument, host_and_ident(TRUE));
5083 smtp_printf("%s\r\n", s);
5091 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5093 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5096 BOOL save_log_testing_mode = log_testing_mode;
5097 address_test_mode = log_testing_mode = TRUE;
5098 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5099 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5101 address_test_mode = FALSE;
5102 log_testing_mode = save_log_testing_mode; /* true for -bh */
5111 if (!tls_advertised)
5113 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5114 US"STARTTLS command used when not advertised");
5118 /* Apply an ACL check if one is defined */
5120 if ( acl_smtp_starttls
5121 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5122 &user_msg, &log_msg)) != OK
5125 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5129 /* RFC 2487 is not clear on when this command may be sent, though it
5130 does state that all information previously obtained from the client
5131 must be discarded if a TLS session is started. It seems reasonable to
5132 do an implied RSET when STARTTLS is received. */
5134 incomplete_transaction_log(US"STARTTLS");
5135 smtp_reset(reset_point);
5137 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5139 /* There's an attack where more data is read in past the STARTTLS command
5140 before TLS is negotiated, then assumed to be part of the secure session
5141 when used afterwards; we use segregated input buffers, so are not
5142 vulnerable, but we want to note when it happens and, for sheer paranoia,
5143 ensure that the buffer is "wiped".
5144 Pipelining sync checks will normally have protected us too, unless disabled
5145 by configuration. */
5147 if (receive_smtp_buffered())
5150 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5151 if (tls_in.active < 0)
5152 smtp_inend = smtp_inptr = smtp_inbuffer;
5153 /* and if TLS is already active, tls_server_start() should fail */
5156 /* There is nothing we value in the input buffer and if TLS is successfully
5157 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5158 fresh content into it. The buffer contains arbitrary content from an
5159 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5160 It seems safest to just wipe away the content rather than leave it as a
5161 target to jump to. */
5163 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5165 /* Attempt to start up a TLS session, and if successful, discard all
5166 knowledge that was obtained previously. At least, that's what the RFC says,
5167 and that's what happens by default. However, in order to work round YAEB,
5168 there is an option to remember the esmtp state. Sigh.
5170 We must allow for an extra EHLO command and an extra AUTH command after
5171 STARTTLS that don't add to the nonmail command count. */
5173 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
5175 if (!tls_remember_esmtp)
5176 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5177 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5178 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5179 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5180 if (sender_helo_name != NULL)
5182 store_free(sender_helo_name);
5183 sender_helo_name = NULL;
5184 host_build_sender_fullhost(); /* Rebuild */
5185 set_process_info("handling incoming TLS connection from %s",
5186 host_and_ident(FALSE));
5189 (sender_host_address ? protocols : protocols_local)
5191 ? pextend + (sender_host_authenticated ? pauthed : 0)
5193 + (tls_in.active >= 0 ? pcrpted : 0)
5196 sender_host_authenticated = NULL;
5197 authenticated_id = NULL;
5198 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5199 DEBUG(D_tls) debug_printf("TLS active\n");
5200 break; /* Successful STARTTLS */
5203 /* Some local configuration problem was discovered before actually trying
5204 to do a TLS handshake; give a temporary error. */
5206 else if (rc == DEFER)
5208 smtp_printf("454 TLS currently unavailable\r\n");
5212 /* Hard failure. Reject everything except QUIT or closed connection. One
5213 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5214 set, but we must still reject all incoming commands. */
5216 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5217 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5220 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5221 smtp_get_connection_info());
5222 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5226 /* It is perhaps arguable as to which exit ACL should be called here,
5227 but as it is probably a situation that almost never arises, it
5228 probably doesn't matter. We choose to call the real QUIT ACL, which in
5229 some sense is perhaps "right". */
5234 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5235 &log_msg)) == ERROR))
5236 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5239 smtp_respond(US"221", 3, TRUE, user_msg);
5241 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
5242 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5243 smtp_get_connection_info());
5248 smtp_printf("554 Security failure\r\n");
5251 tls_close(TRUE, TRUE);
5256 /* The ACL for QUIT is provided for gathering statistical information or
5257 similar; it does not affect the response code, but it can supply a custom
5261 smtp_quit_handler(&user_msg, &log_msg);
5267 smtp_rset_handler();
5268 smtp_reset(reset_point);
5275 smtp_printf("250 OK\r\n");
5279 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5280 used, a check will be done for permitted hosts. Show STARTTLS only if not
5281 already in a TLS session and if it would be advertised in the EHLO
5286 smtp_printf("214-Commands supported:\r\n");
5290 Ustrcat(buffer, " AUTH");
5292 if (tls_in.active < 0 &&
5293 verify_check_host(&tls_advertise_hosts) != FAIL)
5294 Ustrcat(buffer, " STARTTLS");
5296 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5297 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5298 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5299 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5300 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5301 smtp_printf("214%s\r\n", buffer);
5307 incomplete_transaction_log(US"connection lost");
5308 smtp_notquit_exit(US"connection-lost", US"421",
5309 US"%s lost input connection", smtp_active_hostname);
5311 /* Don't log by default unless in the middle of a message, as some mailers
5312 just drop the call rather than sending QUIT, and it clutters up the logs.
5315 if (sender_address != NULL || recipients_count > 0)
5316 log_write(L_lost_incoming_connection,
5318 "unexpected %s while reading SMTP command from %s%s",
5319 sender_host_unknown? "EOF" : "disconnection",
5320 host_and_ident(FALSE), smtp_read_error);
5322 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5323 smtp_get_connection_info(), smtp_read_error);
5331 if (sender_address != NULL)
5333 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5334 US"ETRN is not permitted inside a transaction");
5338 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5339 host_and_ident(FALSE));
5341 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5342 &user_msg, &log_msg)) != OK)
5344 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5348 /* Compute the serialization key for this command. */
5350 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5352 /* If a command has been specified for running as a result of ETRN, we
5353 permit any argument to ETRN. If not, only the # standard form is permitted,
5354 since that is strictly the only kind of ETRN that can be implemented
5355 according to the RFC. */
5357 if (smtp_etrn_command != NULL)
5361 etrn_command = smtp_etrn_command;
5362 deliver_domain = smtp_cmd_data;
5363 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5364 US"ETRN processing", &error);
5365 deliver_domain = NULL;
5368 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5370 smtp_printf("458 Internal failure\r\n");
5375 /* Else set up to call Exim with the -R option. */
5379 if (*smtp_cmd_data++ != '#')
5381 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5382 US"argument must begin with #");
5385 etrn_command = US"exim -R";
5386 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5387 *queue_name ? 4 : 2,
5388 US"-R", smtp_cmd_data,
5389 US"-MCG", queue_name);
5392 /* If we are host-testing, don't actually do anything. */
5398 debug_printf("ETRN command is: %s\n", etrn_command);
5399 debug_printf("ETRN command execution skipped\n");
5401 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5402 else smtp_user_msg(US"250", user_msg);
5407 /* If ETRN queue runs are to be serialized, check the database to
5408 ensure one isn't already running. */
5410 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5412 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
5416 /* Fork a child process and run the command. We don't want to have to
5417 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5418 forking. It should be set that way anyway for external incoming SMTP,
5419 but we save and restore to be tidy. If serialization is required, we
5420 actually run the command in yet another process, so we can wait for it
5421 to complete and then remove the serialization lock. */
5423 oldsignal = signal(SIGCHLD, SIG_IGN);
5425 if ((pid = fork()) == 0)
5427 smtp_input = FALSE; /* This process is not associated with the */
5428 (void)fclose(smtp_in); /* SMTP call any more. */
5429 (void)fclose(smtp_out);
5431 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5433 /* If not serializing, do the exec right away. Otherwise, fork down
5434 into another process. */
5436 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5438 DEBUG(D_exec) debug_print_argv(argv);
5439 exim_nullstd(); /* Ensure std{in,out,err} exist */
5440 execv(CS argv[0], (char *const *)argv);
5441 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5442 etrn_command, strerror(errno));
5443 _exit(EXIT_FAILURE); /* paranoia */
5446 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5447 is, we are in the first subprocess, after forking again. All we can do
5448 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5449 complete, before removing the serialization. */
5452 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5453 "failed: %s", strerror(errno));
5457 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5459 (void)wait(&status);
5460 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5464 enq_end(etrn_serialize_key);
5465 _exit(EXIT_SUCCESS);
5468 /* Back in the top level SMTP process. Check that we started a subprocess
5469 and restore the signal state. */
5473 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5475 smtp_printf("458 Unable to fork process\r\n");
5476 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5480 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5481 else smtp_user_msg(US"250", user_msg);
5484 signal(SIGCHLD, oldsignal);
5489 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5490 US"unexpected argument data");
5494 /* This currently happens only for NULLs, but could be extended. */
5497 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5498 US"NULL character(s) present (shown as '?')");
5499 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5505 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5506 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5507 c = smtp_inend - smtp_inptr;
5508 if (c > 150) c = 150;
5510 incomplete_transaction_log(US"sync failure");
5511 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5512 "(next input sent too soon: pipelining was%s advertised): "
5513 "rejected \"%s\" %s next input=\"%s\"",
5514 pipelining_advertised? "" : " not",
5515 smtp_cmd_buffer, host_and_ident(TRUE),
5516 string_printing(smtp_inptr));
5517 smtp_notquit_exit(US"synchronization-error", US"554",
5518 US"SMTP synchronization error");
5519 done = 1; /* Pretend eof - drops connection */
5523 case TOO_MANY_NONMAIL_CMD:
5524 s = smtp_cmd_buffer;
5525 while (*s != 0 && !isspace(*s)) s++;
5526 incomplete_transaction_log(US"too many non-mail commands");
5527 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5528 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5529 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5530 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5531 done = 1; /* Pretend eof - drops connection */
5534 #ifdef SUPPORT_PROXY
5535 case PROXY_FAIL_IGNORE_CMD:
5536 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5541 if (unknown_command_count++ >= smtp_max_unknown_commands)
5543 log_write(L_smtp_syntax_error, LOG_MAIN,
5544 "SMTP syntax error in \"%s\" %s %s",
5545 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5546 US"unrecognized command");
5547 incomplete_transaction_log(US"unrecognized command");
5548 smtp_notquit_exit(US"bad-commands", US"500",
5549 US"Too many unrecognized commands");
5551 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5552 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5553 string_printing(smtp_cmd_buffer));
5556 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5557 US"unrecognized command");
5561 /* This label is used by goto's inside loops that want to break out to
5562 the end of the command-processing loop. */
5565 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5566 last_was_rcpt = was_rcpt; /* protocol error handling */
5570 return done - 2; /* Convert yield values */
5575 /* End of smtp_in.c */