xref: /netbsd-src/external/ibm-public/postfix/dist/src/tlsproxy/tlsproxy.c (revision 6a493d6bc668897c91594964a732d38505b70cbb)
1 /*	$NetBSD: tlsproxy.c,v 1.1.1.4 2013/09/25 19:06:36 tron Exp $	*/
2 
3 /*++
4 /* NAME
5 /*	tlsproxy 8
6 /* SUMMARY
7 /*	Postfix TLS proxy
8 /* SYNOPSIS
9 /*	\fBtlsproxy\fR [generic Postfix daemon options]
10 /* DESCRIPTION
11 /*	The \fBtlsproxy\fR(8) server implements a server-side TLS
12 /*	proxy. It is used by \fBpostscreen\fR(8) to talk SMTP-over-TLS
13 /*	with remote SMTP clients that are not whitelisted (including
14 /*	clients whose whitelist status has expired),
15 /*	but it should also work for non-SMTP protocols.
16 /*
17 /*	Although one \fBtlsproxy\fR(8) process can serve multiple
18 /*	sessions at the same time, it is a good idea to allow the
19 /*	number of processes to increase with load, so that the
20 /*	service remains responsive.
21 /* PROTOCOL EXAMPLE
22 /* .ad
23 /* .fi
24 /*	The example below concerns \fBpostscreen\fR(8). However,
25 /*	the \fBtlsproxy\fR(8) server is agnostic of the application
26 /*	protocol, and the example is easily adapted to other
27 /*	applications.
28 /*
29 /*	After receiving a valid remote SMTP client STARTTLS command,
30 /*	the \fBpostscreen\fR(8) server sends the remote SMTP client
31 /*	endpoint string, the requested role (server), and the
32 /*	requested timeout to \fBtlsproxy\fR(8).  \fBpostscreen\fR(8)
33 /*	then receives a "TLS available" indication from \fBtlsproxy\fR(8).
34 /*	If the TLS service is available, \fBpostscreen\fR(8) sends
35 /*	the remote SMTP client file descriptor to \fBtlsproxy\fR(8),
36 /*	and sends the plaintext 220 greeting to the remote SMTP
37 /*	client.  This triggers TLS negotiations between the remote
38 /*	SMTP client and \fBtlsproxy\fR(8).  Upon completion of the
39 /*	TLS-level handshake, \fBtlsproxy\fR(8) translates between
40 /*	plaintext from/to \fBpostscreen\fR(8) and ciphertext to/from
41 /*	the remote SMTP client.
42 /* SECURITY
43 /* .ad
44 /* .fi
45 /*	The \fBtlsproxy\fR(8) server is moderately security-sensitive.
46 /*	It talks to untrusted clients on the network. The process
47 /*	can be run chrooted at fixed low privilege.
48 /* DIAGNOSTICS
49 /*	Problems and transactions are logged to \fBsyslogd\fR(8).
50 /* CONFIGURATION PARAMETERS
51 /* .ad
52 /* .fi
53 /*	Changes to \fBmain.cf\fR are not picked up automatically,
54 /*	as \fBtlsproxy\fR(8) processes may run for a long time
55 /*	depending on mail server load.  Use the command "\fBpostfix
56 /*	reload\fR" to speed up a change.
57 /*
58 /*	The text below provides only a parameter summary. See
59 /*	\fBpostconf\fR(5) for more details including examples.
60 /* STARTTLS SUPPORT CONTROLS
61 /* .ad
62 /* .fi
63 /* .IP "\fBtlsproxy_tls_CAfile ($smtpd_tls_CAfile)\fR"
64 /*	A file containing (PEM format) CA certificates of root CAs
65 /*	trusted to sign either remote SMTP client certificates or intermediate
66 /*	CA certificates.
67 /* .IP "\fBtlsproxy_tls_CApath ($smtpd_tls_CApath)\fR"
68 /*	A directory containing (PEM format) CA certificates of root CAs
69 /*	trusted to sign either remote SMTP client certificates or intermediate
70 /*	CA certificates.
71 /* .IP "\fBtlsproxy_tls_always_issue_session_ids ($smtpd_tls_always_issue_session_ids)\fR"
72 /*	Force the Postfix \fBtlsproxy\fR(8) server to issue a TLS session id,
73 /*	even when TLS session caching is turned off.
74 /* .IP "\fBtlsproxy_tls_ask_ccert ($smtpd_tls_ask_ccert)\fR"
75 /*	Ask a remote SMTP client for a client certificate.
76 /* .IP "\fBtlsproxy_tls_ccert_verifydepth ($smtpd_tls_ccert_verifydepth)\fR"
77 /*	The verification depth for remote SMTP client certificates.
78 /* .IP "\fBtlsproxy_tls_cert_file ($smtpd_tls_cert_file)\fR"
79 /*	File with the Postfix \fBtlsproxy\fR(8) server RSA certificate in PEM
80 /*	format.
81 /* .IP "\fBtlsproxy_tls_ciphers ($smtpd_tls_ciphers)\fR"
82 /*	The minimum TLS cipher grade that the Postfix \fBtlsproxy\fR(8) server
83 /*	will use with opportunistic TLS encryption.
84 /* .IP "\fBtlsproxy_tls_dcert_file ($smtpd_tls_dcert_file)\fR"
85 /*	File with the Postfix \fBtlsproxy\fR(8) server DSA certificate in PEM
86 /*	format.
87 /* .IP "\fBtlsproxy_tls_dh1024_param_file ($smtpd_tls_dh1024_param_file)\fR"
88 /*	File with DH parameters that the Postfix \fBtlsproxy\fR(8) server
89 /*	should use with EDH ciphers.
90 /* .IP "\fBtlsproxy_tls_dh512_param_file ($smtpd_tls_dh512_param_file)\fR"
91 /*	File with DH parameters that the Postfix \fBtlsproxy\fR(8) server
92 /*	should use with EDH ciphers.
93 /* .IP "\fBtlsproxy_tls_dkey_file ($smtpd_tls_dkey_file)\fR"
94 /*	File with the Postfix \fBtlsproxy\fR(8) server DSA private key in PEM
95 /*	format.
96 /* .IP "\fBtlsproxy_tls_eccert_file ($smtpd_tls_eccert_file)\fR"
97 /*	File with the Postfix \fBtlsproxy\fR(8) server ECDSA certificate in
98 /*	PEM format.
99 /* .IP "\fBtlsproxy_tls_eckey_file ($smtpd_tls_eckey_file)\fR"
100 /*	File with the Postfix \fBtlsproxy\fR(8) server ECDSA private key in
101 /*	PEM format.
102 /* .IP "\fBtlsproxy_tls_eecdh_grade ($smtpd_tls_eecdh_grade)\fR"
103 /*	The Postfix \fBtlsproxy\fR(8) server security grade for ephemeral
104 /*	elliptic-curve Diffie-Hellman (EECDH) key exchange.
105 /* .IP "\fBtlsproxy_tls_exclude_ciphers ($smtpd_tls_exclude_ciphers)\fR"
106 /*	List of ciphers or cipher types to exclude from the \fBtlsproxy\fR(8)
107 /*	server cipher list at all TLS security levels.
108 /* .IP "\fBtlsproxy_tls_fingerprint_digest ($smtpd_tls_fingerprint_digest)\fR"
109 /*	The message digest algorithm to construct remote SMTP
110 /*	client-certificate
111 /*	fingerprints.
112 /* .IP "\fBtlsproxy_tls_key_file ($smtpd_tls_key_file)\fR"
113 /*	File with the Postfix \fBtlsproxy\fR(8) server RSA private key in PEM
114 /*	format.
115 /* .IP "\fBtlsproxy_tls_loglevel ($smtpd_tls_loglevel)\fR"
116 /*	Enable additional Postfix \fBtlsproxy\fR(8) server logging of TLS
117 /*	activity.
118 /* .IP "\fBtlsproxy_tls_mandatory_ciphers ($smtpd_tls_mandatory_ciphers)\fR"
119 /*	The minimum TLS cipher grade that the Postfix \fBtlsproxy\fR(8) server
120 /*	will use with mandatory TLS encryption.
121 /* .IP "\fBtlsproxy_tls_mandatory_exclude_ciphers ($smtpd_tls_mandatory_exclude_ciphers)\fR"
122 /*	Additional list of ciphers or cipher types to exclude from the
123 /*	\fBtlsproxy\fR(8) server cipher list at mandatory TLS security levels.
124 /* .IP "\fBtlsproxy_tls_mandatory_protocols ($smtpd_tls_mandatory_protocols)\fR"
125 /*	The SSL/TLS protocols accepted by the Postfix \fBtlsproxy\fR(8) server
126 /*	with mandatory TLS encryption.
127 /* .IP "\fBtlsproxy_tls_protocols ($smtpd_tls_protocols)\fR"
128 /*	List of TLS protocols that the Postfix \fBtlsproxy\fR(8) server will
129 /*	exclude or include with opportunistic TLS encryption.
130 /* .IP "\fBtlsproxy_tls_req_ccert ($smtpd_tls_req_ccert)\fR"
131 /*	With mandatory TLS encryption, require a trusted remote SMTP
132 /*	client certificate in order to allow TLS connections to proceed.
133 /* .IP "\fBtlsproxy_tls_security_level ($smtpd_tls_security_level)\fR"
134 /*	The SMTP TLS security level for the Postfix \fBtlsproxy\fR(8) server;
135 /*	when a non-empty value is specified, this overrides the obsolete
136 /*	parameters smtpd_use_tls and smtpd_enforce_tls.
137 /* .IP "\fBtlsproxy_tls_session_cache_timeout ($smtpd_tls_session_cache_timeout)\fR"
138 /*	The expiration time of Postfix \fBtlsproxy\fR(8) server TLS session
139 /*	cache information.
140 /* OBSOLETE STARTTLS SUPPORT CONTROLS
141 /* .ad
142 /* .fi
143 /*	These parameters are supported for compatibility with
144 /*	\fBsmtpd\fR(8) legacy parameters.
145 /* .IP "\fBtlsproxy_use_tls ($smtpd_use_tls)\fR"
146 /*	Opportunistic TLS: announce STARTTLS support to remote SMTP clients,
147 /*	but do not require that clients use TLS encryption.
148 /* .IP "\fBtlsproxy_enforce_tls ($smtpd_enforce_tls)\fR"
149 /*	Mandatory TLS: announce STARTTLS support to remote SMTP clients, and
150 /*	require that clients use TLS encryption.
151 /* RESOURCE CONTROLS
152 /* .ad
153 /* .fi
154 /* .IP "\fBtlsproxy_watchdog_timeout (10s)\fR"
155 /*	How much time a \fBtlsproxy\fR(8) process may take to process local
156 /*	or remote I/O before it is terminated by a built-in watchdog timer.
157 /* MISCELLANEOUS CONTROLS
158 /* .ad
159 /* .fi
160 /* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
161 /*	The default location of the Postfix main.cf and master.cf
162 /*	configuration files.
163 /* .IP "\fBprocess_id (read-only)\fR"
164 /*	The process ID of a Postfix command or daemon process.
165 /* .IP "\fBprocess_name (read-only)\fR"
166 /*	The process name of a Postfix command or daemon process.
167 /* .IP "\fBsyslog_facility (mail)\fR"
168 /*	The syslog facility of Postfix logging.
169 /* .IP "\fBsyslog_name (see 'postconf -d' output)\fR"
170 /*	The mail system name that is prepended to the process name in syslog
171 /*	records, so that "smtpd" becomes, for example, "postfix/smtpd".
172 /* SEE ALSO
173 /*	postscreen(8), Postfix zombie blocker
174 /*	smtpd(8), Postfix SMTP server
175 /*	postconf(5), configuration parameters
176 /*	syslogd(5), system logging
177 /* LICENSE
178 /* .ad
179 /* .fi
180 /*	The Secure Mailer license must be distributed with this software.
181 /* HISTORY
182 /* .ad
183 /* .fi
184 /*	This service was introduced with Postfix version 2.8.
185 /* AUTHOR(S)
186 /*	Wietse Venema
187 /*	IBM T.J. Watson Research
188 /*	P.O. Box 704
189 /*	Yorktown Heights, NY 10598, USA
190 /*--*/
191 
192  /*
193   * System library.
194   */
195 #include <sys_defs.h>
196 
197  /*
198   * Utility library.
199   */
200 #include <msg.h>
201 #include <vstream.h>
202 #include <iostuff.h>
203 #include <nbbio.h>
204 #include <mymalloc.h>
205 
206  /*
207   * Global library.
208   */
209 #include <mail_proto.h>
210 #include <mail_params.h>
211 #include <mail_conf.h>
212 #include <mail_version.h>
213 
214  /*
215   * Master library.
216   */
217 #include <mail_server.h>
218 
219  /*
220   * TLS library.
221   */
222 #ifdef USE_TLS
223 #define TLS_INTERNAL			/* XXX */
224 #include <tls.h>
225 #include <tls_proxy.h>
226 
227  /*
228   * Application-specific.
229   */
230 #include <tlsproxy.h>
231 
232  /*
233   * Tunable parameters. We define our clones of the smtpd(8) parameters to
234   * avoid any confusion about which parameters are used by this program.
235   */
236 int     var_smtpd_tls_ccert_vd;
237 char   *var_smtpd_tls_loglevel;
238 int     var_smtpd_tls_scache_timeout;
239 bool    var_smtpd_use_tls;
240 bool    var_smtpd_enforce_tls;
241 bool    var_smtpd_tls_ask_ccert;
242 bool    var_smtpd_tls_req_ccert;
243 bool    var_smtpd_tls_set_sessid;
244 char   *var_smtpd_relay_ccerts;
245 char   *var_smtpd_tls_cert_file;
246 char   *var_smtpd_tls_key_file;
247 char   *var_smtpd_tls_dcert_file;
248 char   *var_smtpd_tls_dkey_file;
249 char   *var_smtpd_tls_eccert_file;
250 char   *var_smtpd_tls_eckey_file;
251 char   *var_smtpd_tls_CAfile;
252 char   *var_smtpd_tls_CApath;
253 char   *var_smtpd_tls_ciph;
254 char   *var_smtpd_tls_mand_ciph;
255 char   *var_smtpd_tls_excl_ciph;
256 char   *var_smtpd_tls_mand_excl;
257 char   *var_smtpd_tls_proto;
258 char   *var_smtpd_tls_mand_proto;
259 char   *var_smtpd_tls_dh512_param_file;
260 char   *var_smtpd_tls_dh1024_param_file;
261 char   *var_smtpd_tls_eecdh;
262 char   *var_smtpd_tls_fpt_dgst;
263 char   *var_smtpd_tls_level;
264 
265 int     var_tlsp_tls_ccert_vd;
266 char   *var_tlsp_tls_loglevel;
267 int     var_tlsp_tls_scache_timeout;
268 bool    var_tlsp_use_tls;
269 bool    var_tlsp_enforce_tls;
270 bool    var_tlsp_tls_ask_ccert;
271 bool    var_tlsp_tls_req_ccert;
272 bool    var_tlsp_tls_set_sessid;
273 char   *var_tlsp_tls_cert_file;
274 char   *var_tlsp_tls_key_file;
275 char   *var_tlsp_tls_dcert_file;
276 char   *var_tlsp_tls_dkey_file;
277 char   *var_tlsp_tls_eccert_file;
278 char   *var_tlsp_tls_eckey_file;
279 char   *var_tlsp_tls_CAfile;
280 char   *var_tlsp_tls_CApath;
281 char   *var_tlsp_tls_ciph;
282 char   *var_tlsp_tls_mand_ciph;
283 char   *var_tlsp_tls_excl_ciph;
284 char   *var_tlsp_tls_mand_excl;
285 char   *var_tlsp_tls_proto;
286 char   *var_tlsp_tls_mand_proto;
287 char   *var_tlsp_tls_dh512_param_file;
288 char   *var_tlsp_tls_dh1024_param_file;
289 char   *var_tlsp_tls_eecdh;
290 char   *var_tlsp_tls_fpt_dgst;
291 char   *var_tlsp_tls_level;
292 
293 int     var_tlsp_watchdog;
294 
295  /*
296   * TLS per-process status.
297   */
298 static TLS_APPL_STATE *tlsp_server_ctx;
299 static int ask_client_cert;
300 
301  /*
302   * SLMs.
303   */
304 #define STR(x)	vstring_str(x)
305 
306  /*
307   * This code looks simpler than expected. That is the result of a great deal
308   * of effort, mainly in design and analysis.
309   *
310   * By design, postscreen(8) is an event-driven server that must scale up to a
311   * large number of clients. This means that postscreen(8) must avoid doing
312   * CPU-intensive operations such as those in OpenSSL.
313   *
314   * tlsproxy(8) runs the OpenSSL code on behalf of postscreen(8), translating
315   * plaintext SMTP messages from postscreen(8) into SMTP-over-TLS messages to
316   * the remote SMTP client, and vice versa. As long as postscreen(8) does not
317   * receive email messages, the cost of doing TLS operations will be modest.
318   *
319   * Like postscreen(8), one tlsproxy(8) process services multiple remote SMTP
320   * clients. Unlike postscreen(8), there can be more than one tlsproxy(8)
321   * process, although their number is meant to be much smaller than the
322   * number of remote SMTP clients that talk TLS.
323   *
324   * As with postscreen(8), all I/O must be event-driven: encrypted traffic
325   * between tlsproxy(8) and remote SMTP clients, and plaintext traffic
326   * between tlsproxy(8) and postscreen(8). Event-driven plaintext I/O is
327   * straightforward enough that it could be abstracted away with the nbbio(3)
328   * module.
329   *
330   * The event-driven TLS I/O implementation is founded on on-line OpenSSL
331   * documentation, supplemented by statements from OpenSSL developers on
332   * public mailing lists. After some field experience with this code, we may
333   * be able to factor it out as a library module, like nbbio(3), that can
334   * become part of the TLS library.
335   */
336 
337 static void tlsp_ciphertext_event(int, char *);
338 
339 #define TLSP_INIT_TIMEOUT	100
340 
341 /* tlsp_drain - delayed exit after "postfix reload" */
342 
343 static void tlsp_drain(char *unused_service, char **unused_argv)
344 {
345     int     count;
346 
347     /*
348      * After "postfix reload", complete work-in-progress in the background,
349      * instead of dropping already-accepted connections on the floor.
350      *
351      * All error retry counts shall be limited. Instead of blocking here, we
352      * could retry failed fork() operations in the event call-back routines,
353      * but we don't need perfection. The host system is severely overloaded
354      * and service levels are already way down.
355      */
356     for (count = 0; /* see below */ ; count++) {
357 	if (count >= 5) {
358 	    msg_fatal("fork: %m");
359 	} else if (event_server_drain() != 0) {
360 	    msg_warn("fork: %m");
361 	    sleep(1);
362 	    continue;
363 	} else {
364 	    return;
365 	}
366     }
367 }
368 
369 /* tlsp_eval_tls_error - translate TLS "error" result into action */
370 
371 static int tlsp_eval_tls_error(TLSP_STATE *state, int err)
372 {
373     int     ciphertext_fd = state->ciphertext_fd;
374 
375     /*
376      * The ciphertext file descriptor is in non-blocking mode, meaning that
377      * each SSL_accept/connect/read/write/shutdown request may return an
378      * "error" indication that it needs to read or write more ciphertext. The
379      * purpose of this routine is to translate those "error" indications into
380      * the appropriate read/write/timeout event requests.
381      */
382     switch (err) {
383 
384 	/*
385 	 * No error from SSL_read and SSL_write means that the plaintext
386 	 * output buffer is full and that the plaintext input buffer is
387 	 * empty. Stop read/write events on the ciphertext stream. Keep the
388 	 * timer alive as a safety mechanism for the case that the plaintext
389 	 * pseudothreads get stuck.
390 	 */
391     case SSL_ERROR_NONE:
392 	if (state->ssl_last_err != SSL_ERROR_NONE) {
393 	    event_disable_readwrite(ciphertext_fd);
394 	    event_request_timer(tlsp_ciphertext_event, (char *) state,
395 				state->timeout);
396 	    state->ssl_last_err = SSL_ERROR_NONE;
397 	}
398 	return (0);
399 
400 	/*
401 	 * The TLS engine wants to write to the network. Turn on
402 	 * write/timeout events on the ciphertext stream.
403 	 */
404     case SSL_ERROR_WANT_WRITE:
405 	if (state->ssl_last_err == SSL_ERROR_WANT_READ)
406 	    event_disable_readwrite(ciphertext_fd);
407 	if (state->ssl_last_err != SSL_ERROR_WANT_WRITE) {
408 	    event_enable_write(ciphertext_fd, tlsp_ciphertext_event,
409 			       (char *) state);
410 	    state->ssl_last_err = SSL_ERROR_WANT_WRITE;
411 	}
412 	event_request_timer(tlsp_ciphertext_event, (char *) state,
413 			    state->timeout);
414 	return (0);
415 
416 	/*
417 	 * The TLS engine wants to read from the network. Turn on
418 	 * read/timeout events on the ciphertext stream.
419 	 */
420     case SSL_ERROR_WANT_READ:
421 	if (state->ssl_last_err == SSL_ERROR_WANT_WRITE)
422 	    event_disable_readwrite(ciphertext_fd);
423 	if (state->ssl_last_err != SSL_ERROR_WANT_READ) {
424 	    event_enable_read(ciphertext_fd, tlsp_ciphertext_event,
425 			      (char *) state);
426 	    state->ssl_last_err = SSL_ERROR_WANT_READ;
427 	}
428 	event_request_timer(tlsp_ciphertext_event, (char *) state,
429 			    state->timeout);
430 	return (0);
431 
432 	/*
433 	 * Some error. Self-destruct. This automagically cleans up all
434 	 * pending read/write and timeout event requests, making state a
435 	 * dangling pointer.
436 	 */
437     case SSL_ERROR_SSL:
438 	tls_print_errors();
439 	/* FALLTHROUGH */
440     default:
441 	tlsp_state_free(state);
442 	return (-1);
443     }
444 }
445 
446 /* tlsp_strategy - decide what to read or write next. */
447 
448 static void tlsp_strategy(TLSP_STATE *state)
449 {
450     TLS_SESS_STATE *tls_context = state->tls_context;
451     NBBIO  *plaintext_buf;
452     int     ssl_stat;
453     int     ssl_read_err;
454     int     ssl_write_err;
455     int     handshake_err;
456 
457     /*
458      * Be sure to complete the TLS handshake before enabling plain-text I/O.
459      * In case of an unrecoverable error, this automagically cleans up all
460      * pending read/write and timeout event requests.
461      */
462     if (state->flags & TLSP_FLAG_DO_HANDSHAKE) {
463 	ssl_stat = SSL_accept(tls_context->con);
464 	if (ssl_stat != 1) {
465 	    handshake_err = SSL_get_error(tls_context->con, ssl_stat);
466 	    tlsp_eval_tls_error(state, handshake_err);
467 	    /* At this point, state could be a dangling pointer. */
468 	    return;
469 	}
470 	if ((state->tls_context = tls_server_post_accept(tls_context)) == 0) {
471 	    tlsp_state_free(state);
472 	    return;
473 	}
474 	if ((state->req_flags & TLS_PROXY_FLAG_SEND_CONTEXT) != 0
475 	    && (attr_print(state->plaintext_stream, ATTR_FLAG_NONE,
476 			   ATTR_TYPE_FUNC, tls_proxy_context_print,
477 			   (char *) state->tls_context, ATTR_TYPE_END) != 0
478 		|| vstream_fflush(state->plaintext_stream) != 0)) {
479 	    msg_warn("cannot send TLS context: %m");
480 	    tlsp_state_free(state);
481 	    return;
482 	}
483 	state->flags &= ~TLSP_FLAG_DO_HANDSHAKE;
484     }
485 
486     /*
487      * Shutdown and self-destruct after NBBIO error. This automagically
488      * cleans up all pending read/write and timeout event requests. Before
489      * shutting down TLS, we stop all plain-text I/O events but keep the
490      * NBBIO error flags.
491      */
492     plaintext_buf = state->plaintext_buf;
493     if (NBBIO_ERROR_FLAGS(plaintext_buf)) {
494 	if (NBBIO_ACTIVE_FLAGS(plaintext_buf))
495 	    nbbio_disable_readwrite(state->plaintext_buf);
496 	ssl_stat = SSL_shutdown(tls_context->con);
497 	/* XXX Wait for return value 1 if sessions are to be reused? */
498 	if (ssl_stat < 0) {
499 	    handshake_err = SSL_get_error(tls_context->con, ssl_stat);
500 	    tlsp_eval_tls_error(state, handshake_err);
501 	    /* At this point, state could be a dangling pointer. */
502 	    return;
503 	}
504 	tlsp_state_free(state);
505 	return;
506     }
507 
508     /*
509      * Try to move data from the plaintext input buffer to the TLS engine.
510      *
511      * XXX We're supposed to repeat the exact same SSL_write() call arguments
512      * after an SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE result. Rumor has
513      * it that this is because each SSL_write() call reads from the buffer
514      * incrementally, and returns > 0 only after the final byte is processed.
515      * Rumor also has it that setting SSL_MODE_ENABLE_PARTIAL_WRITE and
516      * SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER voids this requirement, and that
517      * repeating the request with an increased request size is OK.
518      * Unfortunately all this is not or poorly documented, and one has to
519      * rely on statements from OpenSSL developers in public mailing archives.
520      */
521     ssl_write_err = SSL_ERROR_NONE;
522     while (NBBIO_READ_PEND(plaintext_buf) > 0) {
523 	ssl_stat = SSL_write(tls_context->con, NBBIO_READ_BUF(plaintext_buf),
524 			     NBBIO_READ_PEND(plaintext_buf));
525 	ssl_write_err = SSL_get_error(tls_context->con, ssl_stat);
526 	if (ssl_write_err != SSL_ERROR_NONE)
527 	    break;
528 	/* Allow the plaintext pseudothread to read more data. */
529 	NBBIO_READ_PEND(plaintext_buf) -= ssl_stat;
530 	if (NBBIO_READ_PEND(plaintext_buf) > 0)
531 	    memmove(NBBIO_READ_BUF(plaintext_buf),
532 		    NBBIO_READ_BUF(plaintext_buf) + ssl_stat,
533 		    NBBIO_READ_PEND(plaintext_buf));
534     }
535 
536     /*
537      * Try to move data from the TLS engine to the plaintext output buffer.
538      * Note: data may arrive as a side effect of calling SSL_write(),
539      * therefore we call SSL_read() after calling SSL_write().
540      *
541      * XXX We're supposed to repeat the exact same SSL_read() call arguments
542      * after an SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE result. This
543      * supposedly means that our plaintext writer must not memmove() the
544      * plaintext output buffer until after the SSL_read() call succeeds. For
545      * now I'll ignore this, because 1) SSL_read() is documented to return
546      * the bytes available, instead of returning > 0 only after the entire
547      * buffer is processed like SSL_write() does; and 2) there is no "read"
548      * equivalent of the SSL_R_BAD_WRITE_RETRY, SSL_MODE_ENABLE_PARTIAL_WRITE
549      * or SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER features.
550      */
551     ssl_read_err = SSL_ERROR_NONE;
552     while (NBBIO_WRITE_PEND(state->plaintext_buf) < NBBIO_BUFSIZE(plaintext_buf)) {
553 	ssl_stat = SSL_read(tls_context->con,
554 			    NBBIO_WRITE_BUF(plaintext_buf)
555 			    + NBBIO_WRITE_PEND(state->plaintext_buf),
556 			    NBBIO_BUFSIZE(plaintext_buf)
557 			    - NBBIO_WRITE_PEND(state->plaintext_buf));
558 	ssl_read_err = SSL_get_error(tls_context->con, ssl_stat);
559 	if (ssl_read_err != SSL_ERROR_NONE)
560 	    break;
561 	NBBIO_WRITE_PEND(plaintext_buf) += ssl_stat;
562     }
563 
564     /*
565      * Try to enable/disable ciphertext read/write events. If SSL_write() was
566      * satisfied, see if SSL_read() wants to do some work. In case of an
567      * unrecoverable error, this automagically destroys the session state
568      * after cleaning up all pending read/write and timeout event requests.
569      */
570     if (tlsp_eval_tls_error(state, ssl_write_err != SSL_ERROR_NONE ?
571 			    ssl_write_err : ssl_read_err) < 0)
572 	return;
573 
574     /*
575      * Try to enable/disable plaintext read/write events. Basically, if we
576      * have nothing to write to the postscreen(8) server, see if there is
577      * something to read. If the write buffer is empty and the read buffer is
578      * full, suspend plaintext I/O until conditions change (but keep the
579      * timer active, as a safety mechanism in case ciphertext I/O gets
580      * stuck).
581      *
582      * XXX In theory, if the client keeps writing fast enough then we would
583      * never read from postscreen(8), and cause postscreen(8) to block. In
584      * practice, postscreen(8) limits the number of client commands, and thus
585      * postscreen(8)'s output will fit in a kernel buffer. This may not be
586      * true in other scenarios where the tlsproxy(8) server could be used.
587      */
588     if (NBBIO_WRITE_PEND(plaintext_buf) > 0) {
589 	if (NBBIO_ACTIVE_FLAGS(plaintext_buf) & NBBIO_FLAG_READ)
590 	    nbbio_disable_readwrite(plaintext_buf);
591 	if ((NBBIO_ACTIVE_FLAGS(plaintext_buf) & NBBIO_FLAG_WRITE) == 0)
592 	    nbbio_enable_write(plaintext_buf, state->timeout);
593     } else if (NBBIO_READ_PEND(plaintext_buf) < NBBIO_BUFSIZE(plaintext_buf)) {
594 	if (NBBIO_ACTIVE_FLAGS(plaintext_buf) & NBBIO_FLAG_WRITE)
595 	    nbbio_disable_readwrite(plaintext_buf);
596 	if ((NBBIO_ACTIVE_FLAGS(plaintext_buf) & NBBIO_FLAG_READ) == 0)
597 	    nbbio_enable_read(plaintext_buf, state->timeout);
598     } else {
599 	if (NBBIO_ACTIVE_FLAGS(plaintext_buf))
600 	    nbbio_slumber(plaintext_buf, state->timeout);
601     }
602 }
603 
604 /* tlsp_plaintext_event - plaintext was read/written */
605 
606 static void tlsp_plaintext_event(int event, char *context)
607 {
608     TLSP_STATE *state = (TLSP_STATE *) context;
609 
610     /*
611      * Safety alert: the plaintext pseudothreads have "slumbered" for too
612      * long (see code above). This means that the ciphertext pseudothreads
613      * are stuck.
614      */
615     if ((NBBIO_ERROR_FLAGS(state->plaintext_buf) & NBBIO_FLAG_TIMEOUT) != 0
616 	&& NBBIO_ACTIVE_FLAGS(state->plaintext_buf) == 0)
617 	msg_warn("deadlock on ciphertext stream for %s", state->remote_endpt);
618 
619     /*
620      * This is easy, because the NBBIO layer has already done the event
621      * decoding and plaintext I/O for us. All we need to do is decide if we
622      * want to read or write more plaintext.
623      */
624     tlsp_strategy(state);
625 }
626 
627 /* tlsp_ciphertext_event - ciphertext is ready to read/write */
628 
629 static void tlsp_ciphertext_event(int event, char *context)
630 {
631     TLSP_STATE *state = (TLSP_STATE *) context;
632 
633     /*
634      * Without a TLS quivalent of the NBBIO layer, we must decode the events
635      * ourselves and do the ciphertext I/O. Then, we can decide if we want to
636      * read or write more ciphertext.
637      */
638     if (event == EVENT_READ || event == EVENT_WRITE) {
639 	tlsp_strategy(state);
640     } else {
641 	if (event == EVENT_TIME && state->ssl_last_err == SSL_ERROR_NONE)
642 	    msg_warn("deadlock on plaintext stream for %s",
643 		     state->remote_endpt);
644 	else
645 	    msg_warn("ciphertext read/write %s for %s",
646 		     event == EVENT_TIME ? "timeout" : "error",
647 		     state->remote_endpt);
648 	tlsp_state_free(state);
649     }
650 }
651 
652 /* tlsp_start_tls - turn on TLS or force disconnect */
653 
654 static void tlsp_start_tls(TLSP_STATE *state)
655 {
656     TLS_SERVER_START_PROPS props;
657     static char *cipher_grade;
658     static VSTRING *cipher_exclusions;
659 
660     /*
661      * The code in this routine is pasted literally from smtpd(8). I am not
662      * going to sanitize this because doing so surely will break things in
663      * unexpected ways.
664      */
665 
666     /*
667      * Perform the before-handshake portion of the per-session initalization.
668      * Pass a null VSTREAM to indicate that this program, will do the
669      * ciphertext I/O, not libtls.
670      *
671      * The cipher grade and exclusions don't change between sessions. Compute
672      * just once and cache.
673      */
674 #define ADD_EXCLUDE(vstr, str) \
675     do { \
676 	if (*(str)) \
677 	    vstring_sprintf_append((vstr), "%s%s", \
678 				   VSTRING_LEN(vstr) ? " " : "", (str)); \
679     } while (0)
680 
681     if (cipher_grade == 0) {
682 	cipher_grade =
683 	    var_tlsp_enforce_tls ? var_tlsp_tls_mand_ciph : var_tlsp_tls_ciph;
684 	cipher_exclusions = vstring_alloc(10);
685 	ADD_EXCLUDE(cipher_exclusions, var_tlsp_tls_excl_ciph);
686 	if (var_tlsp_enforce_tls)
687 	    ADD_EXCLUDE(cipher_exclusions, var_tlsp_tls_mand_excl);
688 	if (ask_client_cert)
689 	    ADD_EXCLUDE(cipher_exclusions, "aNULL");
690     }
691     state->tls_context =
692 	TLS_SERVER_START(&props,
693 			 ctx = tlsp_server_ctx,
694 			 stream = (VSTREAM *) 0,/* unused */
695 			 fd = state->ciphertext_fd,
696 			 timeout = 0,		/* unused */
697 			 requirecert = (var_tlsp_tls_req_ccert
698 					&& var_tlsp_enforce_tls),
699 			 serverid = state->server_id,
700 			 namaddr = state->remote_endpt,
701 			 cipher_grade = cipher_grade,
702 			 cipher_exclusions = STR(cipher_exclusions),
703 			 fpt_dgst = var_tlsp_tls_fpt_dgst);
704 
705     if (state->tls_context == 0) {
706 	tlsp_state_free(state);
707 	return;
708     }
709 
710     /*
711      * XXX Do we care about TLS session rate limits? Good postscreen(8)
712      * clients will occasionally require the tlsproxy to renew their
713      * whitelist status, but bad clients hammering the server can suck up
714      * lots of CPU cycles. Per-client concurrency limits in postscreen(8)
715      * will divert only naive security "researchers".
716      *
717      * XXX Do we care about certificate verification results? Not as long as
718      * postscreen(8) doesn't actually receive email.
719      */
720 }
721 
722 /* tlsp_get_fd_event - receive final postscreen(8) hand-off information */
723 
724 static void tlsp_get_fd_event(int event, char *context)
725 {
726     const char *myname = "tlsp_get_fd_event";
727     TLSP_STATE *state = (TLSP_STATE *) context;
728     int     plaintext_fd = vstream_fileno(state->plaintext_stream);
729 
730     /*
731      * At this point we still manually manage plaintext read/write/timeout
732      * events. Disable I/O and timer events. Don't assume that the first
733      * plaintext request will be a read.
734      */
735     event_disable_readwrite(plaintext_fd);
736     if (event != EVENT_TIME)
737 	event_cancel_timer(tlsp_get_fd_event, (char *) state);
738 
739     /*
740      * Initialize plaintext-related session state.  Once we have this behind
741      * us, the TLSP_STATE destructor will automagically clean up requests for
742      * read/write/timeout events, which makes error recovery easier.
743      *
744      * Register the plaintext event handler for timer cleanup in the TLSP_STATE
745      * destructor. Insert the NBBIO event-driven I/O layer between the
746      * postscreen(8) server and the TLS engine.
747      */
748     if (event != EVENT_READ
749 	|| (state->ciphertext_fd = LOCAL_RECV_FD(plaintext_fd)) < 0) {
750 	msg_warn("%s: receive SMTP client file descriptor: %m", myname);
751 	tlsp_state_free(state);
752 	return;
753     }
754     non_blocking(state->ciphertext_fd, NON_BLOCKING);
755     state->ciphertext_timer = tlsp_ciphertext_event;
756     state->plaintext_buf = nbbio_create(plaintext_fd,
757 					VSTREAM_BUFSIZE, "postscreen",
758 					tlsp_plaintext_event,
759 					(char *) state);
760 
761     /*
762      * Perform the TLS layer before-handshake initialization. We perform the
763      * remainder after the TLS handshake completes.
764      */
765     tlsp_start_tls(state);
766 
767     /*
768      * Trigger the initial proxy server I/Os.
769      */
770     tlsp_strategy(state);
771 }
772 
773 /* tlsp_get_request_event - receive initial postscreen(8) hand-off info */
774 
775 static void tlsp_get_request_event(int event, char *context)
776 {
777     const char *myname = "tlsp_get_request_event";
778     TLSP_STATE *state = (TLSP_STATE *) context;
779     VSTREAM *plaintext_stream = state->plaintext_stream;
780     int     plaintext_fd = vstream_fileno(plaintext_stream);
781     static VSTRING *remote_endpt;
782     static VSTRING *server_id;
783     int     req_flags;
784     int     timeout;
785     int     ready;
786 
787     /*
788      * One-time initialization.
789      */
790     if (remote_endpt == 0) {
791 	remote_endpt = vstring_alloc(10);
792 	server_id = vstring_alloc(10);
793     }
794 
795     /*
796      * At this point we still manually manage plaintext read/write/timeout
797      * events. Turn off timer events. Below we disable read events on error,
798      * and redefine read events on success.
799      */
800     if (event != EVENT_TIME)
801 	event_cancel_timer(tlsp_get_request_event, (char *) state);
802 
803     /*
804      * We must send some data, after receiving the request attributes and
805      * before receiving the remote file descriptor. We can't assume
806      * UNIX-domain socket semantics here.
807      */
808     if (event != EVENT_READ
809 	|| attr_scan(plaintext_stream, ATTR_FLAG_STRICT,
810 		     ATTR_TYPE_STR, MAIL_ATTR_REMOTE_ENDPT, remote_endpt,
811 		     ATTR_TYPE_INT, MAIL_ATTR_FLAGS, &req_flags,
812 		     ATTR_TYPE_INT, MAIL_ATTR_TIMEOUT, &timeout,
813 		     ATTR_TYPE_STR, MAIL_ATTR_SERVER_ID, server_id,
814 		     ATTR_TYPE_END) != 4) {
815 	msg_warn("%s: receive request attributes: %m", myname);
816 	event_disable_readwrite(plaintext_fd);
817 	tlsp_state_free(state);
818 	return;
819     }
820 
821     /*
822      * If the requested TLS engine is unavailable, hang up after making sure
823      * that the plaintext peer has received our "sorry" indication.
824      */
825     ready = ((req_flags & TLS_PROXY_FLAG_ROLE_SERVER) != 0
826 	     && tlsp_server_ctx != 0);
827     if (attr_print(plaintext_stream, ATTR_FLAG_NONE,
828 		   ATTR_TYPE_INT, MAIL_ATTR_STATUS, ready,
829 		   ATTR_TYPE_END) != 0
830 	|| vstream_fflush(plaintext_stream) != 0
831 	|| ready == 0) {
832 	read_wait(plaintext_fd, TLSP_INIT_TIMEOUT);	/* XXX */
833 	event_disable_readwrite(plaintext_fd);
834 	tlsp_state_free(state);
835 	return;
836     }
837 
838     /*
839      * XXX We use the same fixed timeout throughout the entire session for
840      * both plaintext and ciphertext communication. This timeout is just a
841      * safety feature; the real timeout will be enforced by our plaintext
842      * peer.
843      */
844     else {
845 	state->remote_endpt = mystrdup(STR(remote_endpt));
846 	state->server_id = mystrdup(STR(server_id));
847 	msg_info("CONNECT %s %s",
848 		 (req_flags & TLS_PROXY_FLAG_ROLE_SERVER) ? "from" :
849 		 (req_flags & TLS_PROXY_FLAG_ROLE_CLIENT) ? "to" :
850 		 "(bogus_direction)", state->remote_endpt);
851 	state->req_flags = req_flags;
852 	state->timeout = timeout + 10;		/* XXX */
853 	event_enable_read(plaintext_fd, tlsp_get_fd_event, (char *) state);
854 	event_request_timer(tlsp_get_fd_event, (char *) state,
855 			    TLSP_INIT_TIMEOUT);
856 	return;
857     }
858 }
859 
860 /* tlsp_service - handle new client connection */
861 
862 static void tlsp_service(VSTREAM *plaintext_stream,
863 			         char *service,
864 			         char **argv)
865 {
866     TLSP_STATE *state;
867     int     plaintext_fd = vstream_fileno(plaintext_stream);
868 
869     /*
870      * Sanity check. This service takes no command-line arguments.
871      */
872     if (argv[0])
873 	msg_fatal("unexpected command-line argument: %s", argv[0]);
874 
875     /*
876      * This program handles multiple connections, so it must not block. We
877      * use event-driven code for all operations that introduce latency.
878      * Except that attribute lists are sent/received synchronously, once the
879      * socket is found to be ready for transmission.
880      */
881     non_blocking(plaintext_fd, NON_BLOCKING);
882     vstream_control(plaintext_stream,
883 		    VSTREAM_CTL_PATH, "plaintext",
884 		    VSTREAM_CTL_TIMEOUT, 5,
885 		    VSTREAM_CTL_END);
886 
887     /*
888      * Receive postscreen's remote SMTP client address/port and socket.
889      */
890     state = tlsp_state_create(service, plaintext_stream);
891     event_enable_read(plaintext_fd, tlsp_get_request_event, (char *) state);
892     event_request_timer(tlsp_get_request_event, (char *) state,
893 			TLSP_INIT_TIMEOUT);
894 }
895 
896 /* pre_jail_init - pre-jail initialization */
897 
898 static void pre_jail_init(char *unused_name, char **unused_argv)
899 {
900     TLS_SERVER_INIT_PROPS props;
901     const char *cert_file;
902     int     have_server_cert;
903     int     no_server_cert_ok;
904     int     require_server_cert;
905 
906     /*
907      * The code in this routine is pasted literally from smtpd(8). I am not
908      * going to sanitize this because doing so surely will break things in
909      * unexpected ways.
910      */
911     if (*var_tlsp_tls_level) {
912 	switch (tls_level_lookup(var_tlsp_tls_level)) {
913 	default:
914 	    msg_fatal("Invalid TLS level \"%s\"", var_tlsp_tls_level);
915 	    /* NOTREACHED */
916 	    break;
917 	case TLS_LEV_SECURE:
918 	case TLS_LEV_VERIFY:
919 	case TLS_LEV_FPRINT:
920 	    msg_warn("%s: unsupported TLS level \"%s\", using \"encrypt\"",
921 		     VAR_TLSP_TLS_LEVEL, var_tlsp_tls_level);
922 	    /* FALLTHROUGH */
923 	case TLS_LEV_ENCRYPT:
924 	    var_tlsp_enforce_tls = var_tlsp_use_tls = 1;
925 	    break;
926 	case TLS_LEV_MAY:
927 	    var_tlsp_enforce_tls = 0;
928 	    var_tlsp_use_tls = 1;
929 	    break;
930 	case TLS_LEV_NONE:
931 	    var_tlsp_enforce_tls = var_tlsp_use_tls = 0;
932 	    break;
933 	}
934     }
935     var_tlsp_use_tls = var_tlsp_use_tls || var_tlsp_enforce_tls;
936     if (!var_tlsp_use_tls) {
937 	msg_warn("TLS service is requested, but disabled with %s or %s",
938 		 VAR_TLSP_TLS_LEVEL, VAR_TLSP_USE_TLS);
939 	return;
940     }
941 
942     /*
943      * Load TLS keys before dropping privileges.
944      *
945      * Can't use anonymous ciphers if we want client certificates. Must use
946      * anonymous ciphers if we have no certificates.
947      */
948     ask_client_cert = require_server_cert =
949 	(var_tlsp_tls_ask_ccert
950 	 || (var_tlsp_enforce_tls && var_tlsp_tls_req_ccert));
951     if (strcasecmp(var_tlsp_tls_cert_file, "none") == 0) {
952 	no_server_cert_ok = 1;
953 	cert_file = "";
954     } else {
955 	no_server_cert_ok = 0;
956 	cert_file = var_tlsp_tls_cert_file;
957     }
958     have_server_cert =
959 	(*cert_file || *var_tlsp_tls_dcert_file || *var_tlsp_tls_eccert_file);
960 
961     /* Some TLS configuration errors are not show stoppers. */
962     if (!have_server_cert && require_server_cert)
963 	msg_warn("Need a server cert to request client certs");
964     if (!var_tlsp_enforce_tls && var_tlsp_tls_req_ccert)
965 	msg_warn("Can't require client certs unless TLS is required");
966     /* After a show-stopper error, log a warning. */
967     if (have_server_cert || (no_server_cert_ok && !require_server_cert))
968 
969 	/*
970 	 * Large parameter lists are error-prone, so we emulate a language
971 	 * feature that C does not have natively: named parameter lists.
972 	 */
973 	tlsp_server_ctx =
974 	    TLS_SERVER_INIT(&props,
975 			    log_param = VAR_TLSP_TLS_LOGLEVEL,
976 			    log_level = var_tlsp_tls_loglevel,
977 			    verifydepth = var_tlsp_tls_ccert_vd,
978 			    cache_type = TLS_MGR_SCACHE_SMTPD,
979 			    scache_timeout = var_tlsp_tls_scache_timeout,
980 			    set_sessid = var_tlsp_tls_set_sessid,
981 			    cert_file = cert_file,
982 			    key_file = var_tlsp_tls_key_file,
983 			    dcert_file = var_tlsp_tls_dcert_file,
984 			    dkey_file = var_tlsp_tls_dkey_file,
985 			    eccert_file = var_tlsp_tls_eccert_file,
986 			    eckey_file = var_tlsp_tls_eckey_file,
987 			    CAfile = var_tlsp_tls_CAfile,
988 			    CApath = var_tlsp_tls_CApath,
989 			    dh1024_param_file
990 			    = var_tlsp_tls_dh1024_param_file,
991 			    dh512_param_file
992 			    = var_tlsp_tls_dh512_param_file,
993 			    eecdh_grade = var_tlsp_tls_eecdh,
994 			    protocols = var_tlsp_enforce_tls ?
995 			    var_tlsp_tls_mand_proto :
996 			    var_tlsp_tls_proto,
997 			    ask_ccert = ask_client_cert,
998 			    fpt_dgst = var_tlsp_tls_fpt_dgst);
999     else
1000 	msg_warn("No server certs available. TLS can't be enabled");
1001 
1002     /*
1003      * To maintain sanity, allow partial SSL_write() operations, and allow
1004      * SSL_write() buffer pointers to change after a WANT_READ or WANT_WRITE
1005      * result. This is based on OpenSSL developers talking on a mailing list,
1006      * but is not supported by documentation. If this code stops working then
1007      * no-one can be held responsible.
1008      */
1009     if (tlsp_server_ctx)
1010 	SSL_CTX_set_mode(tlsp_server_ctx->ssl_ctx,
1011 			 SSL_MODE_ENABLE_PARTIAL_WRITE
1012 			 | SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
1013 }
1014 
1015 /* post_jail_init - post-jail initialization */
1016 
1017 static void post_jail_init(char *unused_name, char **unused_argv)
1018 {
1019      /* void */ ;
1020 }
1021 
1022 MAIL_VERSION_STAMP_DECLARE;
1023 
1024 /* main - the main program */
1025 
1026 int     main(int argc, char **argv)
1027 {
1028     static const CONFIG_INT_TABLE int_table[] = {
1029 	VAR_SMTPD_TLS_CCERT_VD, DEF_SMTPD_TLS_CCERT_VD, &var_smtpd_tls_ccert_vd, 0, 0,
1030 	0,
1031     };
1032     static const CONFIG_NINT_TABLE nint_table[] = {
1033 	VAR_TLSP_TLS_CCERT_VD, DEF_TLSP_TLS_CCERT_VD, &var_tlsp_tls_ccert_vd, 0, 0,
1034 	0,
1035     };
1036     static const CONFIG_TIME_TABLE time_table[] = {
1037 	VAR_SMTPD_TLS_SCACHTIME, DEF_SMTPD_TLS_SCACHTIME, &var_smtpd_tls_scache_timeout, 0, 0,
1038 	VAR_TLSP_WATCHDOG, DEF_TLSP_WATCHDOG, &var_tlsp_watchdog, 10, 0,
1039 	VAR_TLSP_TLS_SCACHTIME, DEF_TLSP_TLS_SCACHTIME, &var_tlsp_tls_scache_timeout, 0, 0,
1040 	0,
1041     };
1042     static const CONFIG_BOOL_TABLE bool_table[] = {
1043 	VAR_SMTPD_USE_TLS, DEF_SMTPD_USE_TLS, &var_smtpd_use_tls,
1044 	VAR_SMTPD_ENFORCE_TLS, DEF_SMTPD_ENFORCE_TLS, &var_smtpd_enforce_tls,
1045 	VAR_SMTPD_TLS_ACERT, DEF_SMTPD_TLS_ACERT, &var_smtpd_tls_ask_ccert,
1046 	VAR_SMTPD_TLS_RCERT, DEF_SMTPD_TLS_RCERT, &var_smtpd_tls_req_ccert,
1047 	VAR_SMTPD_TLS_SET_SESSID, DEF_SMTPD_TLS_SET_SESSID, &var_smtpd_tls_set_sessid,
1048 	0,
1049     };
1050     static const CONFIG_NBOOL_TABLE nbool_table[] = {
1051 	VAR_TLSP_USE_TLS, DEF_TLSP_USE_TLS, &var_tlsp_use_tls,
1052 	VAR_TLSP_ENFORCE_TLS, DEF_TLSP_ENFORCE_TLS, &var_tlsp_enforce_tls,
1053 	VAR_TLSP_TLS_ACERT, DEF_TLSP_TLS_ACERT, &var_tlsp_tls_ask_ccert,
1054 	VAR_TLSP_TLS_RCERT, DEF_TLSP_TLS_RCERT, &var_tlsp_tls_req_ccert,
1055 	VAR_TLSP_TLS_SET_SESSID, DEF_TLSP_TLS_SET_SESSID, &var_tlsp_tls_set_sessid,
1056 	0,
1057     };
1058     static const CONFIG_STR_TABLE str_table[] = {
1059 	VAR_SMTPD_TLS_CERT_FILE, DEF_SMTPD_TLS_CERT_FILE, &var_smtpd_tls_cert_file, 0, 0,
1060 	VAR_SMTPD_TLS_KEY_FILE, DEF_SMTPD_TLS_KEY_FILE, &var_smtpd_tls_key_file, 0, 0,
1061 	VAR_SMTPD_TLS_DCERT_FILE, DEF_SMTPD_TLS_DCERT_FILE, &var_smtpd_tls_dcert_file, 0, 0,
1062 	VAR_SMTPD_TLS_DKEY_FILE, DEF_SMTPD_TLS_DKEY_FILE, &var_smtpd_tls_dkey_file, 0, 0,
1063 	VAR_SMTPD_TLS_ECCERT_FILE, DEF_SMTPD_TLS_ECCERT_FILE, &var_smtpd_tls_eccert_file, 0, 0,
1064 	VAR_SMTPD_TLS_ECKEY_FILE, DEF_SMTPD_TLS_ECKEY_FILE, &var_smtpd_tls_eckey_file, 0, 0,
1065 	VAR_SMTPD_TLS_CA_FILE, DEF_SMTPD_TLS_CA_FILE, &var_smtpd_tls_CAfile, 0, 0,
1066 	VAR_SMTPD_TLS_CA_PATH, DEF_SMTPD_TLS_CA_PATH, &var_smtpd_tls_CApath, 0, 0,
1067 	VAR_SMTPD_TLS_CIPH, DEF_SMTPD_TLS_CIPH, &var_smtpd_tls_ciph, 1, 0,
1068 	VAR_SMTPD_TLS_MAND_CIPH, DEF_SMTPD_TLS_MAND_CIPH, &var_smtpd_tls_mand_ciph, 1, 0,
1069 	VAR_SMTPD_TLS_EXCL_CIPH, DEF_SMTPD_TLS_EXCL_CIPH, &var_smtpd_tls_excl_ciph, 0, 0,
1070 	VAR_SMTPD_TLS_MAND_EXCL, DEF_SMTPD_TLS_MAND_EXCL, &var_smtpd_tls_mand_excl, 0, 0,
1071 	VAR_SMTPD_TLS_PROTO, DEF_SMTPD_TLS_PROTO, &var_smtpd_tls_proto, 0, 0,
1072 	VAR_SMTPD_TLS_MAND_PROTO, DEF_SMTPD_TLS_MAND_PROTO, &var_smtpd_tls_mand_proto, 0, 0,
1073 	VAR_SMTPD_TLS_512_FILE, DEF_SMTPD_TLS_512_FILE, &var_smtpd_tls_dh512_param_file, 0, 0,
1074 	VAR_SMTPD_TLS_1024_FILE, DEF_SMTPD_TLS_1024_FILE, &var_smtpd_tls_dh1024_param_file, 0, 0,
1075 	VAR_SMTPD_TLS_EECDH, DEF_SMTPD_TLS_EECDH, &var_smtpd_tls_eecdh, 1, 0,
1076 	VAR_SMTPD_TLS_FPT_DGST, DEF_SMTPD_TLS_FPT_DGST, &var_smtpd_tls_fpt_dgst, 1, 0,
1077 	VAR_SMTPD_TLS_LOGLEVEL, DEF_SMTPD_TLS_LOGLEVEL, &var_smtpd_tls_loglevel, 0, 0,
1078 	VAR_SMTPD_TLS_LEVEL, DEF_SMTPD_TLS_LEVEL, &var_smtpd_tls_level, 0, 0,
1079 	VAR_TLSP_TLS_CERT_FILE, DEF_TLSP_TLS_CERT_FILE, &var_tlsp_tls_cert_file, 0, 0,
1080 	VAR_TLSP_TLS_KEY_FILE, DEF_TLSP_TLS_KEY_FILE, &var_tlsp_tls_key_file, 0, 0,
1081 	VAR_TLSP_TLS_DCERT_FILE, DEF_TLSP_TLS_DCERT_FILE, &var_tlsp_tls_dcert_file, 0, 0,
1082 	VAR_TLSP_TLS_DKEY_FILE, DEF_TLSP_TLS_DKEY_FILE, &var_tlsp_tls_dkey_file, 0, 0,
1083 	VAR_TLSP_TLS_ECCERT_FILE, DEF_TLSP_TLS_ECCERT_FILE, &var_tlsp_tls_eccert_file, 0, 0,
1084 	VAR_TLSP_TLS_ECKEY_FILE, DEF_TLSP_TLS_ECKEY_FILE, &var_tlsp_tls_eckey_file, 0, 0,
1085 	VAR_TLSP_TLS_CA_FILE, DEF_TLSP_TLS_CA_FILE, &var_tlsp_tls_CAfile, 0, 0,
1086 	VAR_TLSP_TLS_CA_PATH, DEF_TLSP_TLS_CA_PATH, &var_tlsp_tls_CApath, 0, 0,
1087 	VAR_TLSP_TLS_CIPH, DEF_TLSP_TLS_CIPH, &var_tlsp_tls_ciph, 1, 0,
1088 	VAR_TLSP_TLS_MAND_CIPH, DEF_TLSP_TLS_MAND_CIPH, &var_tlsp_tls_mand_ciph, 1, 0,
1089 	VAR_TLSP_TLS_EXCL_CIPH, DEF_TLSP_TLS_EXCL_CIPH, &var_tlsp_tls_excl_ciph, 0, 0,
1090 	VAR_TLSP_TLS_MAND_EXCL, DEF_TLSP_TLS_MAND_EXCL, &var_tlsp_tls_mand_excl, 0, 0,
1091 	VAR_TLSP_TLS_PROTO, DEF_TLSP_TLS_PROTO, &var_tlsp_tls_proto, 0, 0,
1092 	VAR_TLSP_TLS_MAND_PROTO, DEF_TLSP_TLS_MAND_PROTO, &var_tlsp_tls_mand_proto, 0, 0,
1093 	VAR_TLSP_TLS_512_FILE, DEF_TLSP_TLS_512_FILE, &var_tlsp_tls_dh512_param_file, 0, 0,
1094 	VAR_TLSP_TLS_1024_FILE, DEF_TLSP_TLS_1024_FILE, &var_tlsp_tls_dh1024_param_file, 0, 0,
1095 	VAR_TLSP_TLS_EECDH, DEF_TLSP_TLS_EECDH, &var_tlsp_tls_eecdh, 1, 0,
1096 	VAR_TLSP_TLS_FPT_DGST, DEF_TLSP_TLS_FPT_DGST, &var_tlsp_tls_fpt_dgst, 1, 0,
1097 	VAR_TLSP_TLS_LOGLEVEL, DEF_TLSP_TLS_LOGLEVEL, &var_tlsp_tls_loglevel, 0, 0,
1098 	VAR_TLSP_TLS_LEVEL, DEF_TLSP_TLS_LEVEL, &var_tlsp_tls_level, 0, 0,
1099 	0,
1100     };
1101 
1102     /*
1103      * Fingerprint executables and core dumps.
1104      */
1105     MAIL_VERSION_STAMP_ALLOCATE;
1106 
1107     /*
1108      * Pass control to the single-threaded service skeleton.
1109      */
1110     event_server_main(argc, argv, tlsp_service,
1111 		      MAIL_SERVER_INT_TABLE, int_table,
1112 		      MAIL_SERVER_NINT_TABLE, nint_table,
1113 		      MAIL_SERVER_STR_TABLE, str_table,
1114 		      MAIL_SERVER_BOOL_TABLE, bool_table,
1115 		      MAIL_SERVER_NBOOL_TABLE, nbool_table,
1116 		      MAIL_SERVER_TIME_TABLE, time_table,
1117 		      MAIL_SERVER_PRE_INIT, pre_jail_init,
1118 		      MAIL_SERVER_POST_INIT, post_jail_init,
1119 		      MAIL_SERVER_SLOW_EXIT, tlsp_drain,
1120 		      MAIL_SERVER_WATCHDOG, &var_tlsp_watchdog,
1121 		      0);
1122 }
1123 
1124 #else
1125 
1126 /* tlsp_service - respond to external trigger(s), non-TLS version */
1127 
1128 static void tlsp_service(VSTREAM *stream, char *unused_service,
1129 			         char **unused_argv)
1130 {
1131     msg_info("TLS support is not compiled in -- exiting");
1132     event_server_disconnect(stream);
1133 }
1134 
1135 /* main - the main program */
1136 
1137 int     main(int argc, char **argv)
1138 {
1139 
1140     /*
1141      * We can't simply use msg_fatal() here, because the logging hasn't been
1142      * initialized. The text would disappear because stderr is redirected to
1143      * /dev/null.
1144      *
1145      * We invoke event_server_main() to complete program initialization
1146      * (including logging) and then invoke the tlsp_service() routine to log
1147      * the message that says why this program will not run.
1148      */
1149     event_server_main(argc, argv, tlsp_service,
1150 		      0);
1151 }
1152 
1153 #endif
1154