1 /* $NetBSD: tls_misc.c,v 1.5 2023/12/23 20:30:45 christos Exp $ */
2
3 /*++
4 /* NAME
5 /* tls_misc 3
6 /* SUMMARY
7 /* miscellaneous TLS support routines
8 /* SYNOPSIS
9 /* .SH Public functions
10 /* .nf
11 /* .na
12 /* #include <tls.h>
13 /*
14 /* void tls_log_summary(role, usage, TLScontext)
15 /* TLS_ROLE role;
16 /* TLS_USAGE usage;
17 /* TLS_SESS_STATE *TLScontext;
18 /*
19 /* const char *tls_compile_version(void)
20 /*
21 /* const char *tls_run_version(void)
22 /*
23 /* const char **tls_pkey_algorithms(void)
24 /*
25 /* void tls_pre_jail_init(TLS_ROLE)
26 /* TLS_ROLE role;
27 /*
28 /* .SH Internal functions
29 /* .nf
30 /* .na
31 /* #define TLS_INTERNAL
32 /* #include <tls.h>
33 /*
34 /* char *var_tls_cnf_file;
35 /* char *var_tls_cnf_name;
36 /* char *var_tls_high_clist;
37 /* char *var_tls_medium_clist;
38 /* char *var_tls_null_clist;
39 /* char *var_tls_eecdh_auto;
40 /* char *var_tls_eecdh_strong;
41 /* char *var_tls_eecdh_ultra;
42 /* char *var_tls_ffdhe_auto;
43 /* char *var_tls_dane_digests;
44 /* int var_tls_daemon_rand_bytes;
45 /* bool var_tls_append_def_CA;
46 /* bool var_tls_preempt_clist;
47 /* bool var_tls_bc_pkey_fprint;
48 /* bool var_tls_multi_wildcard;
49 /* char *var_tls_mgr_service;
50 /* char *var_tls_tkt_cipher;
51 /* char *var_openssl_path;
52 /* char *var_tls_server_sni_maps;
53 /* bool var_tls_fast_shutdown;
54 /*
55 /* TLS_APPL_STATE *tls_alloc_app_context(ssl_ctx, log_mask)
56 /* SSL_CTX *ssl_ctx;
57 /* int log_mask;
58 /*
59 /* void tls_free_app_context(app_ctx)
60 /* void *app_ctx;
61 /*
62 /* TLS_SESS_STATE *tls_alloc_sess_context(log_mask, namaddr)
63 /* int log_mask;
64 /* const char *namaddr;
65 /*
66 /* void tls_free_context(TLScontext)
67 /* TLS_SESS_STATE *TLScontext;
68 /*
69 /* void tls_check_version()
70 /*
71 /* long tls_bug_bits()
72 /*
73 /* void tls_param_init()
74 /*
75 /* int tls_library_init(void)
76 /*
77 /* int tls_proto_mask_lims(plist, floor, ceiling)
78 /* const char *plist;
79 /* int *floor;
80 /* int *ceiling;
81 /*
82 /* int tls_cipher_grade(name)
83 /* const char *name;
84 /*
85 /* const char *str_tls_cipher_grade(grade)
86 /* int grade;
87 /*
88 /* const char *tls_set_ciphers(TLScontext, grade, exclusions)
89 /* TLS_SESS_STATE *TLScontext;
90 /* int grade;
91 /* const char *exclusions;
92 /*
93 /* void tls_get_signature_params(TLScontext)
94 /* TLS_SESS_STATE *TLScontext;
95 /*
96 /* void tls_print_errors()
97 /*
98 /* void tls_info_callback(ssl, where, ret)
99 /* const SSL *ssl; /* unused */
100 /* int where;
101 /* int ret;
102 /*
103 /* long tls_bio_dump_cb(bio, cmd, argp, len, argi, argl, ret, processed)
104 /* BIO *bio;
105 /* int cmd;
106 /* const char *argp;
107 /* size_t len;
108 /* int argi;
109 /* long argl; /* unused */
110 /* int ret;
111 /* size_t *processed;
112 /*
113 /* int tls_log_mask(log_param, log_level)
114 /* const char *log_param;
115 /* const char *log_level;
116 /*
117 /* void tls_update_app_logmask(app_ctx, log_mask)
118 /* TLS_APPL_STATE *app_ctx;
119 /* int log_mask;
120 /*
121 /* const EVP_MD *tls_validate_digest(dgst)
122 /* const char *dgst;
123 /* DESCRIPTION
124 /* This module implements public and internal routines that
125 /* support the TLS client and server.
126 /*
127 /* tls_log_summary() logs a summary of a completed TLS connection.
128 /* The "role" argument must be TLS_ROLE_CLIENT for outgoing client
129 /* connections, or TLS_ROLE_SERVER for incoming server connections,
130 /* and the "usage" must be TLS_USAGE_NEW or TLS_USAGE_USED.
131 /*
132 /* tls_compile_version() returns a text string description of
133 /* the compile-time TLS library.
134 /*
135 /* tls_run_version() is just tls_compile_version() but with the runtime
136 /* version instead of the compile-time version.
137 /*
138 /* tls_pkey_algorithms() returns a pointer to null-terminated
139 /* array of string constants with the names of the supported
140 /* public-key algorithms.
141 /*
142 /* tls_alloc_app_context() creates an application context that
143 /* holds the SSL context for the application and related cached state.
144 /*
145 /* tls_free_app_context() deallocates the application context and its
146 /* contents (the application context is stored outside the TLS library).
147 /*
148 /* tls_alloc_sess_context() creates an initialized TLS session context
149 /* structure with the specified log mask and peer name[addr].
150 /*
151 /* tls_free_context() destroys a TLScontext structure
152 /* together with OpenSSL structures that are attached to it.
153 /*
154 /* tls_check_version() logs a warning when the run-time OpenSSL
155 /* library differs in its major, minor or micro number from
156 /* the compile-time OpenSSL headers.
157 /*
158 /* tls_bug_bits() returns the bug compatibility mask appropriate
159 /* for the run-time library. Some of the bug work-arounds are
160 /* not appropriate for some library versions.
161 /*
162 /* tls_param_init() loads main.cf parameters used internally in
163 /* TLS library. Any errors are fatal.
164 /*
165 /* tls_library_init() initializes the OpenSSL library, optionally
166 /* loading an OpenSSL configuration file.
167 /*
168 /* tls_pre_jail_init() opens any tables that need to be opened before
169 /* entering a chroot jail. The "role" parameter must be TLS_ROLE_CLIENT
170 /* for clients and TLS_ROLE_SERVER for servers. Any errors are fatal.
171 /*
172 /* tls_proto_mask_lims() returns a bitmask of excluded protocols, and
173 /* and the protocol version floor/ceiling, given a list (plist) of
174 /* protocols to include or (preceded by a '!') exclude, or constraints
175 /* of the form '>=name', '<=name', '>=hexvalue', '<=hexvalue'. If "plist"
176 /* contains invalid protocol names, TLS_PROTOCOL_INVALID is returned and
177 /* no warning is logged.
178 /*
179 /* tls_cipher_grade() converts a case-insensitive cipher grade name (high,
180 /* medium, null) to the corresponding TLS_CIPHER_ constant. When the
181 /* input specifies an unrecognized grade, tls_cipher_grade() logs no
182 /* warning, and returns TLS_CIPHER_NONE.
183 /*
184 /* str_tls_cipher_grade() converts a cipher grade to a name.
185 /* When the input specifies an undefined grade, str_tls_cipher_grade()
186 /* logs no warning, returns a null pointer.
187 /*
188 /* tls_set_ciphers() applies the requested cipher grade and exclusions
189 /* to the provided TLS session context, returning the resulting cipher
190 /* list string. The return value is the cipherlist used and is
191 /* overwritten upon each call. When the input is invalid,
192 /* tls_set_ciphers() logs a warning, and returns a null result.
193 /*
194 /* tls_get_signature_params() updates the "TLScontext" with handshake
195 /* signature parameters pertaining to TLS 1.3, where the ciphersuite
196 /* no longer describes the asymmetric algorithms employed in the
197 /* handshake, which are negotiated separately. This function
198 /* has no effect for TLS 1.2 and earlier.
199 /*
200 /* tls_print_errors() queries the OpenSSL error stack,
201 /* logs the error messages, and clears the error stack.
202 /*
203 /* tls_info_callback() is a call-back routine for the
204 /* SSL_CTX_set_info_callback() routine. It logs SSL events
205 /* to the Postfix logfile.
206 /*
207 /* tls_bio_dump_cb() is a call-back routine for the
208 /* BIO_set_callback() routine. It logs SSL content to the
209 /* Postfix logfile.
210 /*
211 /* tls_log_mask() converts a TLS log_level value from string
212 /* to mask. The main.cf parameter name is passed along for
213 /* diagnostics.
214 /*
215 /* tls_update_app_logmask() changes the log mask of the
216 /* application TLS context to the new setting.
217 /*
218 /* tls_validate_digest() returns a static handle for the named
219 /* digest algorithm, or NULL on error.
220 /* LICENSE
221 /* .ad
222 /* .fi
223 /* This software is free. You can do with it whatever you want.
224 /* The original author kindly requests that you acknowledge
225 /* the use of his software.
226 /* AUTHOR(S)
227 /* Originally written by:
228 /* Lutz Jaenicke
229 /* BTU Cottbus
230 /* Allgemeine Elektrotechnik
231 /* Universitaetsplatz 3-4
232 /* D-03044 Cottbus, Germany
233 /*
234 /* Updated by:
235 /* Wietse Venema
236 /* IBM T.J. Watson Research
237 /* P.O. Box 704
238 /* Yorktown Heights, NY 10598, USA
239 /*
240 /* Victor Duchovni
241 /* Morgan Stanley
242 /*
243 /* Wietse Venema
244 /* Google, Inc.
245 /* 111 8th Avenue
246 /* New York, NY 10011, USA
247 /*--*/
248
249 /* System library. */
250
251 #include <sys_defs.h>
252 #include <ctype.h>
253 #include <string.h>
254
255 /* Utility library. */
256
257 #include <vstream.h>
258 #include <msg.h>
259 #include <mymalloc.h>
260 #include <vstring.h>
261 #include <stringops.h>
262 #include <argv.h>
263 #include <name_mask.h>
264 #include <name_code.h>
265 #include <dict.h>
266 #include <valid_hostname.h>
267
268 /*
269 * Global library.
270 */
271 #include <mail_params.h>
272 #include <mail_conf.h>
273 #include <maps.h>
274
275 /*
276 * TLS library.
277 */
278 #define TLS_INTERNAL
279 #include <tls.h>
280
281 /* Application-specific. */
282
283 /*
284 * Tunable parameters.
285 */
286 char *var_tls_cnf_file;
287 char *var_tls_cnf_name;
288 char *var_tls_high_clist;
289 char *var_tls_medium_clist;
290 char *var_tls_low_ignored;
291 char *var_tls_export_ignored;
292 char *var_tls_null_clist;
293 int var_tls_daemon_rand_bytes;
294 char *var_tls_eecdh_auto;
295 char *var_tls_eecdh_strong;
296 char *var_tls_eecdh_ultra;
297 char *var_tls_ffdhe_auto;
298 char *var_tls_dane_digests;
299 bool var_tls_append_def_CA;
300 char *var_tls_bug_tweaks;
301 char *var_tls_ssl_options;
302 bool var_tls_bc_pkey_fprint;
303 bool var_tls_multi_wildcard;
304 char *var_tls_mgr_service;
305 char *var_tls_tkt_cipher;
306 char *var_openssl_path;
307 char *var_tls_server_sni_maps;
308 bool var_tls_fast_shutdown;
309 bool var_tls_preempt_clist;
310
311 #ifdef USE_TLS
312
313 static MAPS *tls_server_sni_maps;
314
315 /*
316 * Index to attach TLScontext pointers to SSL objects, so that they can be
317 * accessed by call-back routines.
318 */
319 int TLScontext_index = -1;
320
321 /*
322 * Protocol name <=> mask conversion.
323 */
324 static const NAME_CODE protocol_table[] = {
325 SSL_TXT_SSLV2, TLS_PROTOCOL_SSLv2,
326 SSL_TXT_SSLV3, TLS_PROTOCOL_SSLv3,
327 SSL_TXT_TLSV1, TLS_PROTOCOL_TLSv1,
328 SSL_TXT_TLSV1_1, TLS_PROTOCOL_TLSv1_1,
329 SSL_TXT_TLSV1_2, TLS_PROTOCOL_TLSv1_2,
330 TLS_PROTOCOL_TXT_TLSV1_3, TLS_PROTOCOL_TLSv1_3,
331 0, TLS_PROTOCOL_INVALID,
332 };
333
334 /*
335 * Protocol name => numeric version, for MinProtocol and MaxProtocol
336 */
337 static const NAME_CODE tls_version_table[] = {
338 "None", 0,
339 SSL_TXT_SSLV3, SSL3_VERSION,
340 SSL_TXT_TLSV1, TLS1_VERSION,
341 SSL_TXT_TLSV1_1, TLS1_1_VERSION,
342 SSL_TXT_TLSV1_2, TLS1_2_VERSION,
343 TLS_PROTOCOL_TXT_TLSV1_3, TLS1_3_VERSION,
344 0, -1,
345 };
346
347 /*
348 * SSL_OP_MUMBLE bug work-around name <=> mask conversion.
349 */
350 #define NAMEBUG(x) #x, SSL_OP_##x
351 static const LONG_NAME_MASK ssl_bug_tweaks[] = {
352
353 #ifndef SSL_OP_MICROSOFT_SESS_ID_BUG
354 #define SSL_OP_MICROSOFT_SESS_ID_BUG 0
355 #endif
356 NAMEBUG(MICROSOFT_SESS_ID_BUG),
357
358 #ifndef SSL_OP_NETSCAPE_CHALLENGE_BUG
359 #define SSL_OP_NETSCAPE_CHALLENGE_BUG 0
360 #endif
361 NAMEBUG(NETSCAPE_CHALLENGE_BUG),
362
363 #ifndef SSL_OP_LEGACY_SERVER_CONNECT
364 #define SSL_OP_LEGACY_SERVER_CONNECT 0
365 #endif
366 NAMEBUG(LEGACY_SERVER_CONNECT),
367
368 #ifndef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
369 #define SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG 0
370 #endif
371 NAMEBUG(NETSCAPE_REUSE_CIPHER_CHANGE_BUG),
372 "CVE-2010-4180", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG,
373
374 #ifndef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
375 #define SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG 0
376 #endif
377 NAMEBUG(SSLREF2_REUSE_CERT_TYPE_BUG),
378
379 #ifndef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
380 #define SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER 0
381 #endif
382 NAMEBUG(MICROSOFT_BIG_SSLV3_BUFFER),
383
384 #ifndef SSL_OP_MSIE_SSLV2_RSA_PADDING
385 #define SSL_OP_MSIE_SSLV2_RSA_PADDING 0
386 #endif
387 NAMEBUG(MSIE_SSLV2_RSA_PADDING),
388 "CVE-2005-2969", SSL_OP_MSIE_SSLV2_RSA_PADDING,
389
390 #ifndef SSL_OP_SSLEAY_080_CLIENT_DH_BUG
391 #define SSL_OP_SSLEAY_080_CLIENT_DH_BUG 0
392 #endif
393 NAMEBUG(SSLEAY_080_CLIENT_DH_BUG),
394
395 #ifndef SSL_OP_TLS_D5_BUG
396 #define SSL_OP_TLS_D5_BUG 0
397 #endif
398 NAMEBUG(TLS_D5_BUG),
399
400 #ifndef SSL_OP_TLS_BLOCK_PADDING_BUG
401 #define SSL_OP_TLS_BLOCK_PADDING_BUG 0
402 #endif
403 NAMEBUG(TLS_BLOCK_PADDING_BUG),
404
405 #ifndef SSL_OP_TLS_ROLLBACK_BUG
406 #define SSL_OP_TLS_ROLLBACK_BUG 0
407 #endif
408 NAMEBUG(TLS_ROLLBACK_BUG),
409
410 #ifndef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
411 #define SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS 0
412 #endif
413 NAMEBUG(DONT_INSERT_EMPTY_FRAGMENTS),
414
415 #ifndef SSL_OP_CRYPTOPRO_TLSEXT_BUG
416 #define SSL_OP_CRYPTOPRO_TLSEXT_BUG 0
417 #endif
418 NAMEBUG(CRYPTOPRO_TLSEXT_BUG),
419
420 #ifndef SSL_OP_TLSEXT_PADDING
421 #define SSL_OP_TLSEXT_PADDING 0
422 #endif
423 NAMEBUG(TLSEXT_PADDING),
424
425 #if 0
426
427 /*
428 * XXX: New with OpenSSL 1.1.1, this is turned on implicitly in
429 * SSL_CTX_new() and is not included in SSL_OP_ALL. Allowing users to
430 * disable this would thus be a code change that would require clearing
431 * bug work-around bits in SSL_CTX, after setting SSL_OP_ALL. Since this
432 * is presumably required for TLS 1.3 on today's Internet, the code
433 * change will be done separately later. For now this implicit bug
434 * work-around cannot be disabled via supported Postfix mechanisms.
435 */
436 #ifndef SSL_OP_ENABLE_MIDDLEBOX_COMPAT
437 #define SSL_OP_ENABLE_MIDDLEBOX_COMPAT 0
438 #endif
439 NAMEBUG(ENABLE_MIDDLEBOX_COMPAT),
440 #endif
441
442 0, 0,
443 };
444
445 /*
446 * SSL_OP_MUMBLE option name <=> mask conversion for options that are not
447 * (or may in the future not be) in SSL_OP_ALL. These enable optional
448 * behavior, rather than bug interoperability work-arounds.
449 */
450 #define NAME_SSL_OP(x) #x, SSL_OP_##x
451 static const LONG_NAME_MASK ssl_op_tweaks[] = {
452
453 #ifndef SSL_OP_LEGACY_SERVER_CONNECT
454 #define SSL_OP_LEGACY_SERVER_CONNECT 0
455 #endif
456 NAME_SSL_OP(LEGACY_SERVER_CONNECT),
457
458 #ifndef SSL_OP_NO_TICKET
459 #define SSL_OP_NO_TICKET 0
460 #endif
461 NAME_SSL_OP(NO_TICKET),
462
463 #ifndef SSL_OP_NO_COMPRESSION
464 #define SSL_OP_NO_COMPRESSION 0
465 #endif
466 NAME_SSL_OP(NO_COMPRESSION),
467
468 #ifndef SSL_OP_NO_RENEGOTIATION
469 #define SSL_OP_NO_RENEGOTIATION 0
470 #endif
471 NAME_SSL_OP(NO_RENEGOTIATION),
472
473 #ifndef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
474 #define SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION 0
475 #endif
476 NAME_SSL_OP(NO_SESSION_RESUMPTION_ON_RENEGOTIATION),
477
478 #ifndef SSL_OP_PRIORITIZE_CHACHA
479 #define SSL_OP_PRIORITIZE_CHACHA 0
480 #endif
481 NAME_SSL_OP(PRIORITIZE_CHACHA),
482
483 #ifndef SSL_OP_ENABLE_MIDDLEBOX_COMPAT
484 #define SSL_OP_ENABLE_MIDDLEBOX_COMPAT 0
485 #endif
486 NAME_SSL_OP(ENABLE_MIDDLEBOX_COMPAT),
487
488 0, 0,
489 };
490
491 /*
492 * Once these have been a NOOP long enough, they might some day be removed
493 * from OpenSSL. The defines below will avoid bitrot issues if/when that
494 * happens.
495 */
496 #ifndef SSL_OP_SINGLE_DH_USE
497 #define SSL_OP_SINGLE_DH_USE 0
498 #endif
499 #ifndef SSL_OP_SINGLE_ECDH_USE
500 #define SSL_OP_SINGLE_ECDH_USE 0
501 #endif
502
503 /*
504 * Ciphersuite name <=> code conversion.
505 */
506 const NAME_CODE tls_cipher_grade_table[] = {
507 "high", TLS_CIPHER_HIGH,
508 "medium", TLS_CIPHER_MEDIUM,
509 "low", TLS_CIPHER_MEDIUM,
510 "export", TLS_CIPHER_MEDIUM,
511 "null", TLS_CIPHER_NULL,
512 "invalid", TLS_CIPHER_NONE,
513 0, TLS_CIPHER_NONE,
514 };
515
516 /*
517 * Log keyword <=> mask conversion.
518 */
519 #define TLS_LOG_0 TLS_LOG_NONE
520 #define TLS_LOG_1 TLS_LOG_SUMMARY
521 #define TLS_LOG_2 (TLS_LOG_1 | TLS_LOG_VERBOSE | TLS_LOG_CACHE | TLS_LOG_DEBUG)
522 #define TLS_LOG_3 (TLS_LOG_2 | TLS_LOG_TLSPKTS)
523 #define TLS_LOG_4 (TLS_LOG_3 | TLS_LOG_ALLPKTS)
524
525 static const NAME_MASK tls_log_table[] = {
526 "0", TLS_LOG_0,
527 "none", TLS_LOG_NONE,
528 "1", TLS_LOG_1,
529 "routine", TLS_LOG_1,
530 "2", TLS_LOG_2,
531 "debug", TLS_LOG_2,
532 "3", TLS_LOG_3,
533 "ssl-expert", TLS_LOG_3,
534 "4", TLS_LOG_4,
535 "ssl-developer", TLS_LOG_4,
536 "5", TLS_LOG_4, /* for good measure */
537 "6", TLS_LOG_4, /* for good measure */
538 "7", TLS_LOG_4, /* for good measure */
539 "8", TLS_LOG_4, /* for good measure */
540 "9", TLS_LOG_4, /* for good measure */
541 "summary", TLS_LOG_SUMMARY,
542 "untrusted", TLS_LOG_UNTRUSTED,
543 "peercert", TLS_LOG_PEERCERT,
544 "certmatch", TLS_LOG_CERTMATCH,
545 "verbose", TLS_LOG_VERBOSE, /* Postfix TLS library verbose */
546 "cache", TLS_LOG_CACHE,
547 "dane", TLS_LOG_DANE, /* DANE policy construction */
548 "ssl-debug", TLS_LOG_DEBUG, /* SSL library debug/verbose */
549 "ssl-handshake-packet-dump", TLS_LOG_TLSPKTS,
550 "ssl-session-packet-dump", TLS_LOG_TLSPKTS | TLS_LOG_ALLPKTS,
551 0, 0,
552 };
553
554 /*
555 * Parsed OpenSSL version number.
556 */
557 typedef struct {
558 int major;
559 int minor;
560 int micro;
561 int patch;
562 int status;
563 } TLS_VINFO;
564
565 /* tls_log_mask - Convert user TLS loglevel to internal log feature mask */
566
tls_log_mask(const char * log_param,const char * log_level)567 int tls_log_mask(const char *log_param, const char *log_level)
568 {
569 int mask;
570
571 mask = name_mask_opt(log_param, tls_log_table, log_level,
572 NAME_MASK_ANY_CASE | NAME_MASK_RETURN);
573 return (mask);
574 }
575
576 /* tls_update_app_logmask - update log level after init */
577
tls_update_app_logmask(TLS_APPL_STATE * app_ctx,int log_mask)578 void tls_update_app_logmask(TLS_APPL_STATE *app_ctx, int log_mask)
579 {
580 app_ctx->log_mask = log_mask;
581 }
582
583 /* parse_version - parse TLS protocol version name or hex number */
584
parse_tls_version(const char * tok,int * version)585 static int parse_tls_version(const char *tok, int *version)
586 {
587 int code = name_code(tls_version_table, NAME_CODE_FLAG_NONE, tok);
588 char *_end;
589 unsigned long ulval;
590
591 if (code != -1) {
592 *version = code;
593 return (0);
594 }
595 errno = 0;
596 ulval = strtoul(tok, &_end, 16);
597 if (*_end != 0
598 || (ulval == ULONG_MAX && errno == ERANGE)
599 || ulval > INT_MAX)
600 return TLS_PROTOCOL_INVALID;
601
602 *version = (int) ulval;
603 return (0);
604 }
605
606 /* tls_proto_mask_lims - protocols to exclude and floor/ceiling */
607
tls_proto_mask_lims(const char * plist,int * floor,int * ceiling)608 int tls_proto_mask_lims(const char *plist, int *floor, int *ceiling)
609 {
610 char *save;
611 char *tok;
612 char *cp;
613 int code;
614 int exclude = 0;
615 int include = 0;
616
617 #define FREE_AND_RETURN(ptr, res) do { \
618 myfree(ptr); \
619 return (res); \
620 } while (0)
621
622 *floor = *ceiling = 0;
623
624 save = cp = mystrdup(plist);
625 while ((tok = mystrtok(&cp, CHARS_COMMA_SP ":")) != 0) {
626 if (strncmp(tok, ">=", 2) == 0)
627 code = parse_tls_version(tok + 2, floor);
628 else if (strncmp(tok, "<=", 2) == 0)
629 code = parse_tls_version(tok + 2, ceiling);
630 else if (*tok == '!')
631 exclude |= code =
632 name_code(protocol_table, NAME_CODE_FLAG_NONE, ++tok);
633 else
634 include |= code =
635 name_code(protocol_table, NAME_CODE_FLAG_NONE, tok);
636 if (code == TLS_PROTOCOL_INVALID)
637 FREE_AND_RETURN(save, TLS_PROTOCOL_INVALID);
638 }
639
640 /*
641 * When the include list is empty, use only the explicit exclusions.
642 * Otherwise, also exclude the complement of the include list from the
643 * built-in list of known protocols. There is no way to exclude protocols
644 * we don't know about at compile time, and this is unavoidable because
645 * the OpenSSL API works with compile-time *exclusion* bit-masks.
646 */
647 FREE_AND_RETURN(save,
648 (include ? (exclude | (TLS_KNOWN_PROTOCOLS & ~include)) : exclude));
649 }
650
651 /* tls_param_init - Load TLS related config parameters */
652
tls_param_init(void)653 void tls_param_init(void)
654 {
655 /* If this changes, update TLS_CLIENT_PARAMS in tls_proxy.h. */
656 static const CONFIG_STR_TABLE str_table[] = {
657 VAR_TLS_CNF_FILE, DEF_TLS_CNF_FILE, &var_tls_cnf_file, 0, 0,
658 VAR_TLS_CNF_NAME, DEF_TLS_CNF_NAME, &var_tls_cnf_name, 0, 0,
659 VAR_TLS_HIGH_CLIST, DEF_TLS_HIGH_CLIST, &var_tls_high_clist, 1, 0,
660 VAR_TLS_MEDIUM_CLIST, DEF_TLS_MEDIUM_CLIST, &var_tls_medium_clist, 1, 0,
661 VAR_TLS_LOW_CLIST, DEF_TLS_LOW_CLIST, &var_tls_low_ignored, 0, 0,
662 VAR_TLS_EXPORT_CLIST, DEF_TLS_EXPORT_CLIST, &var_tls_export_ignored, 0, 0,
663 VAR_TLS_NULL_CLIST, DEF_TLS_NULL_CLIST, &var_tls_null_clist, 1, 0,
664 VAR_TLS_EECDH_AUTO, DEF_TLS_EECDH_AUTO, &var_tls_eecdh_auto, 0, 0,
665 VAR_TLS_EECDH_STRONG, DEF_TLS_EECDH_STRONG, &var_tls_eecdh_strong, 1, 0,
666 VAR_TLS_EECDH_ULTRA, DEF_TLS_EECDH_ULTRA, &var_tls_eecdh_ultra, 1, 0,
667 VAR_TLS_FFDHE_AUTO, DEF_TLS_FFDHE_AUTO, &var_tls_ffdhe_auto, 0, 0,
668 VAR_TLS_BUG_TWEAKS, DEF_TLS_BUG_TWEAKS, &var_tls_bug_tweaks, 0, 0,
669 VAR_TLS_SSL_OPTIONS, DEF_TLS_SSL_OPTIONS, &var_tls_ssl_options, 0, 0,
670 VAR_TLS_DANE_DIGESTS, DEF_TLS_DANE_DIGESTS, &var_tls_dane_digests, 1, 0,
671 VAR_TLS_MGR_SERVICE, DEF_TLS_MGR_SERVICE, &var_tls_mgr_service, 1, 0,
672 VAR_TLS_TKT_CIPHER, DEF_TLS_TKT_CIPHER, &var_tls_tkt_cipher, 0, 0,
673 VAR_OPENSSL_PATH, DEF_OPENSSL_PATH, &var_openssl_path, 1, 0,
674 0,
675 };
676
677 /* If this changes, update TLS_CLIENT_PARAMS in tls_proxy.h. */
678 static const CONFIG_INT_TABLE int_table[] = {
679 VAR_TLS_DAEMON_RAND_BYTES, DEF_TLS_DAEMON_RAND_BYTES, &var_tls_daemon_rand_bytes, 1, 0,
680 0,
681 };
682
683 /* If this changes, update TLS_CLIENT_PARAMS in tls_proxy.h. */
684 static const CONFIG_BOOL_TABLE bool_table[] = {
685 VAR_TLS_APPEND_DEF_CA, DEF_TLS_APPEND_DEF_CA, &var_tls_append_def_CA,
686 VAR_TLS_BC_PKEY_FPRINT, DEF_TLS_BC_PKEY_FPRINT, &var_tls_bc_pkey_fprint,
687 VAR_TLS_PREEMPT_CLIST, DEF_TLS_PREEMPT_CLIST, &var_tls_preempt_clist,
688 VAR_TLS_MULTI_WILDCARD, DEF_TLS_MULTI_WILDCARD, &var_tls_multi_wildcard,
689 VAR_TLS_FAST_SHUTDOWN, DEF_TLS_FAST_SHUTDOWN, &var_tls_fast_shutdown,
690 0,
691 };
692 static int init_done;
693
694 if (init_done)
695 return;
696 init_done = 1;
697
698 get_mail_conf_str_table(str_table);
699 get_mail_conf_int_table(int_table);
700 get_mail_conf_bool_table(bool_table);
701 }
702
703 /* tls_library_init - perform OpenSSL library initialization */
704
tls_library_init(void)705 int tls_library_init(void)
706 {
707 OPENSSL_INIT_SETTINGS *init_settings;
708 char *conf_name = *var_tls_cnf_name ? var_tls_cnf_name : 0;
709 char *conf_file = 0;
710 unsigned long init_opts = 0;
711
712 #define TLS_LIB_INIT_TODO (-1)
713 #define TLS_LIB_INIT_ERR (0)
714 #define TLS_LIB_INIT_OK (1)
715
716 static int init_res = TLS_LIB_INIT_TODO;
717
718 if (init_res != TLS_LIB_INIT_TODO)
719 return (init_res);
720
721 /*
722 * Backwards compatibility: skip this function unless the Postfix
723 * configuration actually has non-default tls_config_xxx settings.
724 */
725 if (strcmp(var_tls_cnf_file, DEF_TLS_CNF_FILE) == 0
726 && strcmp(var_tls_cnf_name, DEF_TLS_CNF_NAME) == 0) {
727 if (msg_verbose)
728 msg_info("tls_library_init: using backwards-compatible defaults");
729 return (init_res = TLS_LIB_INIT_OK);
730 }
731 if ((init_settings = OPENSSL_INIT_new()) == 0) {
732 msg_warn("error allocating OpenSSL init settings, "
733 "disabling TLS support");
734 return (init_res = TLS_LIB_INIT_ERR);
735 }
736 #define TLS_LIB_INIT_RETURN(x) \
737 do { OPENSSL_INIT_free(init_settings); return (init_res = (x)); } while(0)
738
739 #if OPENSSL_VERSION_NUMBER < 0x1010102fL
740
741 /*
742 * OpenSSL 1.1.0 through 1.1.1a, no support for custom configuration
743 * files, disabling loading of the file, or getting strict error
744 * handling. Thus, the only supported configuration file is "default".
745 */
746 if (strcmp(var_tls_cnf_file, "default") != 0) {
747 msg_warn("non-default %s = %s requires OpenSSL 1.1.1b or later, "
748 "disabling TLS support", VAR_TLS_CNF_FILE, var_tls_cnf_file);
749 TLS_LIB_INIT_RETURN(TLS_LIB_INIT_ERR);
750 }
751 #else
752 {
753 unsigned long file_flags = 0;
754
755 /*-
756 * OpenSSL 1.1.1b or later:
757 * We can now use a non-default configuration file, or
758 * use none at all. We can also request strict error
759 * reporting.
760 */
761 if (strcmp(var_tls_cnf_file, "none") == 0) {
762 init_opts |= OPENSSL_INIT_NO_LOAD_CONFIG;
763 } else if (strcmp(var_tls_cnf_file, "default") == 0) {
764
765 /*
766 * The default global config file is optional. With "default"
767 * initialisation we don't insist on a match for the requested
768 * application name, allowing fallback to the default application
769 * name, even when a non-default application name is specified.
770 * Errors in loading the default configuration are ignored.
771 */
772 conf_file = 0;
773 file_flags |= CONF_MFLAGS_IGNORE_MISSING_FILE;
774 file_flags |= CONF_MFLAGS_DEFAULT_SECTION;
775 file_flags |= CONF_MFLAGS_IGNORE_RETURN_CODES | CONF_MFLAGS_SILENT;
776 } else if (*var_tls_cnf_file == '/') {
777
778 /*
779 * A custom config file must be present, error reporting is
780 * strict and the configuration section for the requested
781 * application name does not fall back to "openssl_conf" when
782 * missing.
783 */
784 conf_file = var_tls_cnf_file;
785 } else {
786 msg_warn("non-default %s = %s is not an absolute pathname, "
787 "disabling TLS support", VAR_TLS_CNF_FILE, var_tls_cnf_file);
788 TLS_LIB_INIT_RETURN(TLS_LIB_INIT_ERR);
789 }
790
791 OPENSSL_INIT_set_config_file_flags(init_settings, file_flags);
792 }
793 #endif
794
795 if (conf_file)
796 OPENSSL_INIT_set_config_filename(init_settings, conf_file);
797 if (conf_name)
798 OPENSSL_INIT_set_config_appname(init_settings, conf_name);
799
800 if (OPENSSL_init_ssl(init_opts, init_settings) <= 0) {
801 if ((init_opts & OPENSSL_INIT_NO_LOAD_CONFIG) == 0)
802 msg_warn("error loading the '%s' settings from the %s OpenSSL "
803 "configuration file, disabling TLS support",
804 conf_name ? conf_name : "global",
805 conf_file ? conf_file : "default");
806 else
807 msg_warn("error initializing the OpenSSL library, "
808 "disabling TLS support");
809 tls_print_errors();
810 TLS_LIB_INIT_RETURN(TLS_LIB_INIT_ERR);
811 }
812 TLS_LIB_INIT_RETURN(TLS_LIB_INIT_OK);
813 }
814
815 /* tls_pre_jail_init - Load TLS related pre-jail tables */
816
tls_pre_jail_init(TLS_ROLE role)817 void tls_pre_jail_init(TLS_ROLE role)
818 {
819 static const CONFIG_STR_TABLE str_table[] = {
820 VAR_TLS_SERVER_SNI_MAPS, DEF_TLS_SERVER_SNI_MAPS, &var_tls_server_sni_maps, 0, 0,
821 0,
822 };
823 int flags;
824
825 tls_param_init();
826
827 /* Nothing for clients at this time */
828 if (role != TLS_ROLE_SERVER)
829 return;
830
831 get_mail_conf_str_table(str_table);
832 if (*var_tls_server_sni_maps == 0)
833 return;
834
835 flags = DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX | DICT_FLAG_SRC_RHS_IS_FILE;
836 tls_server_sni_maps =
837 maps_create(VAR_TLS_SERVER_SNI_MAPS, var_tls_server_sni_maps, flags);
838 }
839
840 /* server_sni_callback - process client's SNI extension */
841
server_sni_callback(SSL * ssl,int * alert,void * arg)842 static int server_sni_callback(SSL *ssl, int *alert, void *arg)
843 {
844 SSL_CTX *sni_ctx = (SSL_CTX *) arg;
845 TLS_SESS_STATE *TLScontext = SSL_get_ex_data(ssl, TLScontext_index);
846 const char *sni = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
847 const char *cp = sni;
848 const char *pem;
849
850 /* SNI is silently ignored when we don't care or is NULL or empty */
851 if (!sni_ctx || !tls_server_sni_maps || !sni || !*sni)
852 return SSL_TLSEXT_ERR_NOACK;
853
854 if (!valid_hostname(sni, DONT_GRIPE)) {
855 msg_warn("TLS SNI from %s is invalid: %s",
856 TLScontext->namaddr, sni);
857 return SSL_TLSEXT_ERR_NOACK;
858 }
859
860 /*
861 * With TLS 1.3, when the client's proposed key share is not supported by
862 * the server, the server may issue a HelloRetryRequest (HRR), and the
863 * client will then retry with a new key share on a curve supported by
864 * the server. This results in the SNI callback running twice for the
865 * same connection.
866 *
867 * When that happens, The client MUST send the essentially the same hello
868 * message, including the SNI name, and since we've already loaded our
869 * certificate chain, we don't need to do it again! Therefore, if we've
870 * already recorded the peer SNI name, just check that it has not
871 * changed, and return success.
872 */
873 if (TLScontext->peer_sni) {
874 if (strcmp(sni, TLScontext->peer_sni) == 0)
875 return SSL_TLSEXT_ERR_OK;
876 msg_warn("TLS SNI changed from %s initially %s, %s after hello retry",
877 TLScontext->namaddr, TLScontext->peer_sni, sni);
878 return SSL_TLSEXT_ERR_NOACK;
879 }
880 do {
881 /* Don't silently skip maps opened with the wrong flags. */
882 pem = maps_file_find(tls_server_sni_maps, cp, 0);
883 } while (!pem
884 && !tls_server_sni_maps->error
885 && (cp = strchr(cp + 1, '.')) != 0);
886
887 if (!pem) {
888 if (tls_server_sni_maps->error) {
889 msg_warn("%s: %s map lookup problem",
890 tls_server_sni_maps->title, sni);
891 *alert = SSL_AD_INTERNAL_ERROR;
892 return SSL_TLSEXT_ERR_ALERT_FATAL;
893 }
894 msg_info("TLS SNI %s from %s not matched, using default chain",
895 sni, TLScontext->namaddr);
896
897 /*
898 * XXX: We could lie and pretend to accept the name, but since we've
899 * previously not implemented the callback (with OpenSSL then
900 * declining the extension), and nothing bad happened, declining it
901 * explicitly should be safe.
902 */
903 return SSL_TLSEXT_ERR_NOACK;
904 }
905 SSL_set_SSL_CTX(ssl, sni_ctx);
906 if (tls_load_pem_chain(ssl, pem, sni) != 0) {
907 /* errors already logged */
908 *alert = SSL_AD_INTERNAL_ERROR;
909 return SSL_TLSEXT_ERR_ALERT_FATAL;
910 }
911 TLScontext->peer_sni = mystrdup(sni);
912 return SSL_TLSEXT_ERR_OK;
913 }
914
915 /* tls_set_ciphers - Set SSL context cipher list */
916
tls_set_ciphers(TLS_SESS_STATE * TLScontext,const char * grade,const char * exclusions)917 const char *tls_set_ciphers(TLS_SESS_STATE *TLScontext, const char *grade,
918 const char *exclusions)
919 {
920 const char *myname = "tls_set_ciphers";
921 static VSTRING *buf;
922 char *save;
923 char *cp;
924 char *tok;
925
926 if (buf == 0)
927 buf = vstring_alloc(10);
928 VSTRING_RESET(buf);
929
930 switch (tls_cipher_grade(grade)) {
931 case TLS_CIPHER_NONE:
932 msg_warn("%s: invalid cipher grade: \"%s\"",
933 TLScontext->namaddr, grade);
934 return (0);
935 case TLS_CIPHER_HIGH:
936 vstring_strcpy(buf, var_tls_high_clist);
937 break;
938 case TLS_CIPHER_MEDIUM:
939 vstring_strcpy(buf, var_tls_medium_clist);
940 break;
941 case TLS_CIPHER_NULL:
942 vstring_strcpy(buf, var_tls_null_clist);
943 break;
944 default:
945 /* Internal error, valid grade, but missing case label. */
946 msg_panic("%s: unexpected cipher grade: %s", myname, grade);
947 }
948
949 /*
950 * The base lists for each grade can't be empty.
951 */
952 if (VSTRING_LEN(buf) == 0)
953 msg_panic("%s: empty \"%s\" cipherlist", myname, grade);
954
955 /*
956 * Apply locally-specified exclusions.
957 */
958 #define CIPHER_SEP CHARS_COMMA_SP ":"
959 if (exclusions != 0) {
960 cp = save = mystrdup(exclusions);
961 while ((tok = mystrtok(&cp, CIPHER_SEP)) != 0) {
962
963 /*
964 * Can't exclude ciphers that start with modifiers.
965 */
966 if (strchr("!+-@", *tok)) {
967 msg_warn("%s: invalid unary '!+-@' in cipher exclusion: %s",
968 TLScontext->namaddr, tok);
969 return (0);
970 }
971 vstring_sprintf_append(buf, ":!%s", tok);
972 }
973 myfree(save);
974 }
975 ERR_clear_error();
976 if (SSL_set_cipher_list(TLScontext->con, vstring_str(buf)) == 0) {
977 msg_warn("%s: error setting cipher grade: \"%s\"",
978 TLScontext->namaddr, grade);
979 tls_print_errors();
980 return (0);
981 }
982 return (vstring_str(buf));
983 }
984
985 /* ec_curve_name - copy EC key curve group name */
986
987 #ifndef OPENSSL_NO_EC
ec_curve_name(EVP_PKEY * pkey)988 static char *ec_curve_name(EVP_PKEY *pkey)
989 {
990 char *curve = 0;
991
992 #if OPENSSL_VERSION_PREREQ(3,0)
993 size_t namelen;
994
995 if (EVP_PKEY_get_group_name(pkey, 0, 0, &namelen)) {
996 curve = mymalloc(++namelen);
997 if (!EVP_PKEY_get_group_name(pkey, curve, namelen, 0)) {
998 myfree(curve);
999 curve = 0;
1000 }
1001 }
1002 #else
1003 EC_KEY *eckey = EVP_PKEY_get0_EC_KEY(pkey);
1004 int nid = EC_GROUP_get_curve_name(EC_KEY_get0_group(eckey));
1005 const char *tmp = EC_curve_nid2nist(nid);
1006
1007 if (!tmp)
1008 tmp = OBJ_nid2sn(nid);
1009 if (tmp)
1010 curve = mystrdup(tmp);
1011 #endif
1012 return (curve);
1013 }
1014
1015 #endif
1016
1017 /* tls_get_signature_params - TLS 1.3 signature details */
1018
tls_get_signature_params(TLS_SESS_STATE * TLScontext)1019 void tls_get_signature_params(TLS_SESS_STATE *TLScontext)
1020 {
1021 const char *kex_name = 0;
1022 const char *locl_sig_name = 0;
1023 const char *locl_sig_dgst = 0;
1024 const char *peer_sig_name = 0;
1025 const char *peer_sig_dgst = 0;
1026 char *kex_curve = 0;
1027 char *locl_sig_curve = 0;
1028 char *peer_sig_curve = 0;
1029 int nid;
1030 SSL *ssl = TLScontext->con;
1031 int srvr = SSL_is_server(ssl);
1032 EVP_PKEY *dh_pkey = 0;
1033 X509 *local_cert;
1034 EVP_PKEY *local_pkey = 0;
1035 X509 *peer_cert;
1036 EVP_PKEY *peer_pkey = 0;
1037
1038 #define SIG_PROP(c, s, p) (*((s) ? &c->srvr_sig_##p : &c->clnt_sig_##p))
1039
1040 if (SSL_version(ssl) < TLS1_3_VERSION)
1041 return;
1042
1043 if (tls_get_peer_dh_pubkey(ssl, &dh_pkey)) {
1044 switch (nid = EVP_PKEY_id(dh_pkey)) {
1045 default:
1046 kex_name = OBJ_nid2sn(EVP_PKEY_type(nid));
1047 break;
1048
1049 case EVP_PKEY_DH:
1050 kex_name = "DHE";
1051 TLScontext->kex_bits = EVP_PKEY_bits(dh_pkey);
1052 break;
1053
1054 #ifndef OPENSSL_NO_EC
1055 case EVP_PKEY_EC:
1056 kex_name = "ECDHE";
1057 kex_curve = ec_curve_name(dh_pkey);
1058 break;
1059 #endif
1060 }
1061 EVP_PKEY_free(dh_pkey);
1062 }
1063
1064 /*
1065 * On the client end, the certificate may be preset, but not used, so we
1066 * check via SSL_get_signature_nid(). This means that local signature
1067 * data on clients requires at least 1.1.1a.
1068 */
1069 if (srvr || SSL_get_signature_nid(ssl, &nid))
1070 local_cert = SSL_get_certificate(ssl);
1071 else
1072 local_cert = 0;
1073
1074 /* Signature algorithms for the local end of the connection */
1075 if (local_cert) {
1076 local_pkey = X509_get0_pubkey(local_cert);
1077
1078 /*
1079 * Override the built-in name for the "ECDSA" algorithms OID, with
1080 * the more familiar name. For "RSA" keys report "RSA-PSS", which
1081 * must be used with TLS 1.3.
1082 */
1083 if ((nid = EVP_PKEY_type(EVP_PKEY_id(local_pkey))) != NID_undef) {
1084 switch (nid) {
1085 default:
1086 locl_sig_name = OBJ_nid2sn(nid);
1087 break;
1088
1089 case EVP_PKEY_RSA:
1090 /* For RSA, TLS 1.3 mandates PSS signatures */
1091 locl_sig_name = "RSA-PSS";
1092 SIG_PROP(TLScontext, srvr, bits) = EVP_PKEY_bits(local_pkey);
1093 break;
1094
1095 #ifndef OPENSSL_NO_EC
1096 case EVP_PKEY_EC:
1097 locl_sig_name = "ECDSA";
1098 locl_sig_curve = ec_curve_name(local_pkey);
1099 break;
1100 #endif
1101 }
1102 /* No X509_free(local_cert) */
1103 }
1104
1105 /*
1106 * With Ed25519 and Ed448 there is no pre-signature digest, but the
1107 * accessor does not fail, rather we get NID_undef.
1108 */
1109 if (SSL_get_signature_nid(ssl, &nid) && nid != NID_undef)
1110 locl_sig_dgst = OBJ_nid2sn(nid);
1111 }
1112 /* Signature algorithms for the peer end of the connection */
1113 if ((peer_cert = TLS_PEEK_PEER_CERT(ssl)) != 0) {
1114 peer_pkey = X509_get0_pubkey(peer_cert);
1115
1116 /*
1117 * Override the built-in name for the "ECDSA" algorithms OID, with
1118 * the more familiar name. For "RSA" keys report "RSA-PSS", which
1119 * must be used with TLS 1.3.
1120 */
1121 if ((nid = EVP_PKEY_type(EVP_PKEY_id(peer_pkey))) != NID_undef) {
1122 switch (nid) {
1123 default:
1124 peer_sig_name = OBJ_nid2sn(nid);
1125 break;
1126
1127 case EVP_PKEY_RSA:
1128 /* For RSA, TLS 1.3 mandates PSS signatures */
1129 peer_sig_name = "RSA-PSS";
1130 SIG_PROP(TLScontext, !srvr, bits) = EVP_PKEY_bits(peer_pkey);
1131 break;
1132
1133 #ifndef OPENSSL_NO_EC
1134 case EVP_PKEY_EC:
1135 peer_sig_name = "ECDSA";
1136 peer_sig_curve = ec_curve_name(peer_pkey);
1137 break;
1138 #endif
1139 }
1140 }
1141
1142 /*
1143 * With Ed25519 and Ed448 there is no pre-signature digest, but the
1144 * accessor does not fail, rather we get NID_undef.
1145 */
1146 if (SSL_get_peer_signature_nid(ssl, &nid) && nid != NID_undef)
1147 peer_sig_dgst = OBJ_nid2sn(nid);
1148
1149 TLS_FREE_PEER_CERT(peer_cert);
1150 }
1151 if (kex_name) {
1152 TLScontext->kex_name = mystrdup(kex_name);
1153 TLScontext->kex_curve = kex_curve;
1154 }
1155 if (locl_sig_name) {
1156 SIG_PROP(TLScontext, srvr, name) = mystrdup(locl_sig_name);
1157 SIG_PROP(TLScontext, srvr, curve) = locl_sig_curve;
1158 if (locl_sig_dgst)
1159 SIG_PROP(TLScontext, srvr, dgst) = mystrdup(locl_sig_dgst);
1160 }
1161 if (peer_sig_name) {
1162 SIG_PROP(TLScontext, !srvr, name) = mystrdup(peer_sig_name);
1163 SIG_PROP(TLScontext, !srvr, curve) = peer_sig_curve;
1164 if (peer_sig_dgst)
1165 SIG_PROP(TLScontext, !srvr, dgst) = mystrdup(peer_sig_dgst);
1166 }
1167 }
1168
1169 /* tls_log_summary - TLS loglevel 1 one-liner, embellished with TLS 1.3 details */
1170
tls_log_summary(TLS_ROLE role,TLS_USAGE usage,TLS_SESS_STATE * ctx)1171 void tls_log_summary(TLS_ROLE role, TLS_USAGE usage, TLS_SESS_STATE *ctx)
1172 {
1173 VSTRING *msg = vstring_alloc(100);
1174 const char *direction = (role == TLS_ROLE_CLIENT) ? "to" : "from";
1175 const char *sni = (role == TLS_ROLE_CLIENT) ? 0 : ctx->peer_sni;
1176
1177 /*
1178 * When SNI was sent and accepted, the server-side log message now
1179 * includes a "to <sni-name>" detail after the "from <namaddr>" detail
1180 * identifying the remote client. We don't presently log (purportedly)
1181 * accepted SNI on the client side.
1182 */
1183 vstring_sprintf(msg, "%s TLS connection %s %s %s%s%s: %s"
1184 " with cipher %s (%d/%d bits)",
1185 !TLS_CERT_IS_PRESENT(ctx) ? "Anonymous" :
1186 TLS_CERT_IS_SECURED(ctx) ? "Verified" :
1187 TLS_CERT_IS_TRUSTED(ctx) ? "Trusted" : "Untrusted",
1188 usage == TLS_USAGE_NEW ? "established" : "reused",
1189 direction, ctx->namaddr, sni ? " to " : "", sni ? sni : "",
1190 ctx->protocol, ctx->cipher_name, ctx->cipher_usebits,
1191 ctx->cipher_algbits);
1192
1193 if (ctx->kex_name && *ctx->kex_name) {
1194 vstring_sprintf_append(msg, " key-exchange %s", ctx->kex_name);
1195 if (ctx->kex_curve && *ctx->kex_curve)
1196 vstring_sprintf_append(msg, " (%s)", ctx->kex_curve);
1197 else if (ctx->kex_bits > 0)
1198 vstring_sprintf_append(msg, " (%d bits)", ctx->kex_bits);
1199 }
1200 if (ctx->srvr_sig_name && *ctx->srvr_sig_name) {
1201 vstring_sprintf_append(msg, " server-signature %s",
1202 ctx->srvr_sig_name);
1203 if (ctx->srvr_sig_curve && *ctx->srvr_sig_curve)
1204 vstring_sprintf_append(msg, " (%s)", ctx->srvr_sig_curve);
1205 else if (ctx->srvr_sig_bits > 0)
1206 vstring_sprintf_append(msg, " (%d bits)", ctx->srvr_sig_bits);
1207 if (ctx->srvr_sig_dgst && *ctx->srvr_sig_dgst)
1208 vstring_sprintf_append(msg, " server-digest %s",
1209 ctx->srvr_sig_dgst);
1210 }
1211 if (ctx->clnt_sig_name && *ctx->clnt_sig_name) {
1212 vstring_sprintf_append(msg, " client-signature %s",
1213 ctx->clnt_sig_name);
1214 if (ctx->clnt_sig_curve && *ctx->clnt_sig_curve)
1215 vstring_sprintf_append(msg, " (%s)", ctx->clnt_sig_curve);
1216 else if (ctx->clnt_sig_bits > 0)
1217 vstring_sprintf_append(msg, " (%d bits)", ctx->clnt_sig_bits);
1218 if (ctx->clnt_sig_dgst && *ctx->clnt_sig_dgst)
1219 vstring_sprintf_append(msg, " client-digest %s",
1220 ctx->clnt_sig_dgst);
1221 }
1222 msg_info("%s", vstring_str(msg));
1223 vstring_free(msg);
1224 }
1225
1226 /* tls_alloc_app_context - allocate TLS application context */
1227
tls_alloc_app_context(SSL_CTX * ssl_ctx,SSL_CTX * sni_ctx,int log_mask)1228 TLS_APPL_STATE *tls_alloc_app_context(SSL_CTX *ssl_ctx, SSL_CTX *sni_ctx,
1229 int log_mask)
1230 {
1231 TLS_APPL_STATE *app_ctx;
1232
1233 app_ctx = (TLS_APPL_STATE *) mymalloc(sizeof(*app_ctx));
1234
1235 /* See portability note below with other memset() call. */
1236 memset((void *) app_ctx, 0, sizeof(*app_ctx));
1237 app_ctx->ssl_ctx = ssl_ctx;
1238 app_ctx->sni_ctx = sni_ctx;
1239 app_ctx->log_mask = log_mask;
1240
1241 /* See also: cache purging code in tls_set_ciphers(). */
1242 app_ctx->cache_type = 0;
1243
1244 if (tls_server_sni_maps) {
1245 SSL_CTX_set_tlsext_servername_callback(ssl_ctx, server_sni_callback);
1246 SSL_CTX_set_tlsext_servername_arg(ssl_ctx, (void *) sni_ctx);
1247 }
1248 return (app_ctx);
1249 }
1250
1251 /* tls_free_app_context - Free TLS application context */
1252
tls_free_app_context(TLS_APPL_STATE * app_ctx)1253 void tls_free_app_context(TLS_APPL_STATE *app_ctx)
1254 {
1255 if (app_ctx->ssl_ctx)
1256 SSL_CTX_free(app_ctx->ssl_ctx);
1257 if (app_ctx->sni_ctx)
1258 SSL_CTX_free(app_ctx->sni_ctx);
1259 if (app_ctx->cache_type)
1260 myfree(app_ctx->cache_type);
1261 myfree((void *) app_ctx);
1262 }
1263
1264 /* tls_alloc_sess_context - allocate TLS session context */
1265
tls_alloc_sess_context(int log_mask,const char * namaddr)1266 TLS_SESS_STATE *tls_alloc_sess_context(int log_mask, const char *namaddr)
1267 {
1268 TLS_SESS_STATE *TLScontext;
1269
1270 /*
1271 * PORTABILITY: Do not assume that null pointers are all-zero bits. Use
1272 * explicit assignments to initialize pointers.
1273 *
1274 * See the C language FAQ item 5.17, or if you have time to burn,
1275 * http://www.google.com/search?q=zero+bit+null+pointer
1276 *
1277 * However, it's OK to use memset() to zero integer values.
1278 */
1279 TLScontext = (TLS_SESS_STATE *) mymalloc(sizeof(TLS_SESS_STATE));
1280 memset((void *) TLScontext, 0, sizeof(*TLScontext));
1281 TLScontext->con = 0;
1282 TLScontext->cache_type = 0;
1283 TLScontext->serverid = 0;
1284 TLScontext->peer_CN = 0;
1285 TLScontext->issuer_CN = 0;
1286 TLScontext->peer_sni = 0;
1287 TLScontext->peer_cert_fprint = 0;
1288 TLScontext->peer_pkey_fprint = 0;
1289 TLScontext->protocol = 0;
1290 TLScontext->cipher_name = 0;
1291 TLScontext->kex_name = 0;
1292 TLScontext->kex_curve = 0;
1293 TLScontext->clnt_sig_name = 0;
1294 TLScontext->clnt_sig_curve = 0;
1295 TLScontext->clnt_sig_dgst = 0;
1296 TLScontext->srvr_sig_name = 0;
1297 TLScontext->srvr_sig_curve = 0;
1298 TLScontext->srvr_sig_dgst = 0;
1299 TLScontext->log_mask = log_mask;
1300 TLScontext->namaddr = lowercase(mystrdup(namaddr));
1301 TLScontext->mdalg = 0; /* Alias for props->mdalg */
1302 TLScontext->dane = 0; /* Alias for props->dane */
1303 TLScontext->errordepth = -1;
1304 TLScontext->errorcode = X509_V_OK;
1305 TLScontext->errorcert = 0;
1306
1307 return (TLScontext);
1308 }
1309
1310 /* tls_free_context - deallocate TLScontext and members */
1311
tls_free_context(TLS_SESS_STATE * TLScontext)1312 void tls_free_context(TLS_SESS_STATE *TLScontext)
1313 {
1314
1315 /*
1316 * Free the SSL structure and the BIOs. Warning: the internal_bio is
1317 * connected to the SSL structure and is automatically freed with it. Do
1318 * not free it again (core dump)!! Only free the network_bio.
1319 */
1320 if (TLScontext->con != 0)
1321 SSL_free(TLScontext->con);
1322
1323 if (TLScontext->namaddr)
1324 myfree(TLScontext->namaddr);
1325 if (TLScontext->serverid)
1326 myfree(TLScontext->serverid);
1327
1328 if (TLScontext->peer_CN)
1329 myfree(TLScontext->peer_CN);
1330 if (TLScontext->issuer_CN)
1331 myfree(TLScontext->issuer_CN);
1332 if (TLScontext->peer_sni)
1333 myfree(TLScontext->peer_sni);
1334 if (TLScontext->peer_cert_fprint)
1335 myfree(TLScontext->peer_cert_fprint);
1336 if (TLScontext->peer_pkey_fprint)
1337 myfree(TLScontext->peer_pkey_fprint);
1338 if (TLScontext->kex_name)
1339 myfree((void *) TLScontext->kex_name);
1340 if (TLScontext->kex_curve)
1341 myfree((void *) TLScontext->kex_curve);
1342 if (TLScontext->clnt_sig_name)
1343 myfree((void *) TLScontext->clnt_sig_name);
1344 if (TLScontext->clnt_sig_curve)
1345 myfree((void *) TLScontext->clnt_sig_curve);
1346 if (TLScontext->clnt_sig_dgst)
1347 myfree((void *) TLScontext->clnt_sig_dgst);
1348 if (TLScontext->srvr_sig_name)
1349 myfree((void *) TLScontext->srvr_sig_name);
1350 if (TLScontext->srvr_sig_curve)
1351 myfree((void *) TLScontext->srvr_sig_curve);
1352 if (TLScontext->srvr_sig_dgst)
1353 myfree((void *) TLScontext->srvr_sig_dgst);
1354 if (TLScontext->errorcert)
1355 X509_free(TLScontext->errorcert);
1356
1357 myfree((void *) TLScontext);
1358 }
1359
1360 /* tls_version_split - Split OpenSSL version number into major, minor, ... */
1361
tls_version_split(unsigned long version,TLS_VINFO * info)1362 static void tls_version_split(unsigned long version, TLS_VINFO *info)
1363 {
1364
1365 /*
1366 * OPENSSL_VERSION_NUMBER(3):
1367 *
1368 * OPENSSL_VERSION_NUMBER is a numeric release version identifier:
1369 *
1370 * MMNNFFPPS: major minor fix patch status
1371 *
1372 * The status nibble has one of the values 0 for development, 1 to e for
1373 * betas 1 to 14, and f for release. Parsed OpenSSL version number. for
1374 * example: 0x1010103f == 1.1.1c.
1375 */
1376 info->status = version & 0xf;
1377 version >>= 4;
1378 info->patch = version & 0xff;
1379 version >>= 8;
1380 info->micro = version & 0xff;
1381 version >>= 8;
1382 info->minor = version & 0xff;
1383 version >>= 8;
1384 info->major = version & 0xff;
1385 }
1386
1387 /* tls_check_version - Detect mismatch between headers and library. */
1388
tls_check_version(void)1389 void tls_check_version(void)
1390 {
1391 TLS_VINFO hdr_info;
1392 TLS_VINFO lib_info;
1393
1394 tls_version_split(OPENSSL_VERSION_NUMBER, &hdr_info);
1395 tls_version_split(OpenSSL_version_num(), &lib_info);
1396
1397 /*
1398 * Warn if run-time library is different from compile-time library,
1399 * allowing later run-time "micro" versions starting with 1.1.0.
1400 */
1401 if (lib_info.major != hdr_info.major
1402 || lib_info.minor != hdr_info.minor
1403 || (lib_info.micro != hdr_info.micro
1404 && (lib_info.micro < hdr_info.micro
1405 || hdr_info.major == 0
1406 || (hdr_info.major == 1 && hdr_info.minor == 0))))
1407 msg_warn("run-time library vs. compile-time header version mismatch: "
1408 "OpenSSL %d.%d.%d may not be compatible with OpenSSL %d.%d.%d",
1409 lib_info.major, lib_info.minor, lib_info.micro,
1410 hdr_info.major, hdr_info.minor, hdr_info.micro);
1411 }
1412
1413 /* tls_compile_version - compile-time OpenSSL version */
1414
tls_compile_version(void)1415 const char *tls_compile_version(void)
1416 {
1417 return (OPENSSL_VERSION_TEXT);
1418 }
1419
1420 /* tls_run_version - run-time version "major.minor.micro" */
1421
tls_run_version(void)1422 const char *tls_run_version(void)
1423 {
1424 return (OpenSSL_version(OPENSSL_VERSION));
1425 }
1426
tls_pkey_algorithms(void)1427 const char **tls_pkey_algorithms(void)
1428 {
1429
1430 /*
1431 * Return an array, not string, so that the result can be inspected
1432 * without parsing. Sort the result alphabetically, not chronologically.
1433 */
1434 static const char *algs[] = {
1435 #ifndef OPENSSL_NO_DSA
1436 "dsa",
1437 #endif
1438 #ifndef OPENSSL_NO_ECDSA
1439 "ecdsa",
1440 #endif
1441 #ifndef OPENSSL_NO_RSA
1442 "rsa",
1443 #endif
1444 0,
1445 };
1446
1447 return (algs);
1448 }
1449
1450 /* tls_bug_bits - SSL bug compatibility bits for this OpenSSL version */
1451
tls_bug_bits(void)1452 long tls_bug_bits(void)
1453 {
1454 long bits = SSL_OP_ALL; /* Work around all known bugs */
1455
1456 /*
1457 * Silently ignore any strings that don't appear in the tweaks table, or
1458 * hex bits that are not in SSL_OP_ALL.
1459 */
1460 if (*var_tls_bug_tweaks) {
1461 bits &= ~long_name_mask_opt(VAR_TLS_BUG_TWEAKS, ssl_bug_tweaks,
1462 var_tls_bug_tweaks, NAME_MASK_ANY_CASE |
1463 NAME_MASK_NUMBER | NAME_MASK_WARN);
1464 #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG
1465 /* Not relevant to SMTP */
1466 bits &= ~SSL_OP_SAFARI_ECDHE_ECDSA_BUG;
1467 #endif
1468 }
1469
1470 /*
1471 * Allow users to set options not in SSL_OP_ALL, and not already managed
1472 * via other Postfix parameters.
1473 */
1474 if (*var_tls_ssl_options) {
1475 long enable;
1476
1477 enable = long_name_mask_opt(VAR_TLS_SSL_OPTIONS, ssl_op_tweaks,
1478 var_tls_ssl_options, NAME_MASK_ANY_CASE |
1479 NAME_MASK_NUMBER | NAME_MASK_WARN);
1480 enable &= ~(SSL_OP_ALL | TLS_SSL_OP_MANAGED_BITS);
1481 bits |= enable;
1482 }
1483
1484 /*
1485 * We unconditionally avoid re-use of ephemeral keys, note that we set DH
1486 * keys via a callback, so reuse was never possible, but the ECDH key is
1487 * set statically, so that is potentially subject to reuse. Set both
1488 * options just in case.
1489 */
1490 bits |= SSL_OP_SINGLE_ECDH_USE | SSL_OP_SINGLE_DH_USE;
1491
1492 /*
1493 * Unconditionally disable a CPU resource attack. There's no good reason
1494 * to enable TLS renegotiation in the middle of an SMTP connection.
1495 */
1496 bits |= SSL_OP_NO_RENEGOTIATION;
1497 return (bits);
1498 }
1499
1500 /* tls_print_errors - print and clear the error stack */
1501
tls_print_errors(void)1502 void tls_print_errors(void)
1503 {
1504 unsigned long err;
1505 char buffer[1024]; /* XXX */
1506 const char *file;
1507 const char *data;
1508 int line;
1509 int flags;
1510
1511 #if OPENSSL_VERSION_PREREQ(3,0)
1512 /* XXX: We're ignoring the function name, do we want to log it? */
1513 #define ERRGET(fi, l, d, fl) ERR_get_error_all(fi, l, 0, d, fl)
1514 #else
1515 #define ERRGET(fi, l, d, fl) ERR_get_error_line_data(fi, l, d, fl)
1516 #endif
1517
1518 while ((err = ERRGET(&file, &line, &data, &flags)) != 0) {
1519 ERR_error_string_n(err, buffer, sizeof(buffer));
1520 if (flags & ERR_TXT_STRING)
1521 msg_warn("TLS library problem: %s:%s:%d:%s:",
1522 buffer, file, line, data);
1523 else
1524 msg_warn("TLS library problem: %s:%s:%d:", buffer, file, line);
1525 }
1526 }
1527
1528 /* tls_info_callback - callback for logging SSL events via Postfix */
1529
tls_info_callback(const SSL * s,int where,int ret)1530 void tls_info_callback(const SSL *s, int where, int ret)
1531 {
1532 char *str;
1533 int w;
1534
1535 /* Adapted from OpenSSL apps/s_cb.c. */
1536
1537 w = where & ~SSL_ST_MASK;
1538
1539 if (w & SSL_ST_CONNECT)
1540 str = "SSL_connect";
1541 else if (w & SSL_ST_ACCEPT)
1542 str = "SSL_accept";
1543 else
1544 str = "unknown";
1545
1546 if (where & SSL_CB_LOOP) {
1547 msg_info("%s:%s", str, SSL_state_string_long((SSL *) s));
1548 } else if (where & SSL_CB_ALERT) {
1549 str = (where & SSL_CB_READ) ? "read" : "write";
1550 if ((ret & 0xff) != SSL3_AD_CLOSE_NOTIFY)
1551 msg_info("SSL3 alert %s:%s:%s", str,
1552 SSL_alert_type_string_long(ret),
1553 SSL_alert_desc_string_long(ret));
1554 } else if (where & SSL_CB_EXIT) {
1555 if (ret == 0)
1556 msg_info("%s:failed in %s",
1557 str, SSL_state_string_long((SSL *) s));
1558 else if (ret < 0) {
1559 #ifndef LOG_NON_ERROR_STATES
1560 switch (SSL_get_error((SSL *) s, ret)) {
1561 case SSL_ERROR_WANT_READ:
1562 case SSL_ERROR_WANT_WRITE:
1563 /* Don't log non-error states. */
1564 break;
1565 default:
1566 #endif
1567 msg_info("%s:error in %s",
1568 str, SSL_state_string_long((SSL *) s));
1569 #ifndef LOG_NON_ERROR_STATES
1570 }
1571 #endif
1572 }
1573 }
1574 }
1575
1576 /*
1577 * taken from OpenSSL crypto/bio/b_dump.c.
1578 *
1579 * Modified to save a lot of strcpy and strcat by Matti Aarnio.
1580 *
1581 * Rewritten by Wietse to eliminate fixed-size stack buffer, array index
1582 * multiplication and division, sprintf() and strcpy(), and lots of strlen()
1583 * calls. We could make it a little faster by using a fixed-size stack-based
1584 * buffer.
1585 *
1586 * 200412 - use %lx to print pointers, after casting them to unsigned long.
1587 */
1588
1589 #define TRUNCATE_SPACE_NULL
1590 #define DUMP_WIDTH 16
1591 #define VERT_SPLIT 7
1592
tls_dump_buffer(const unsigned char * start,int len)1593 static void tls_dump_buffer(const unsigned char *start, int len)
1594 {
1595 VSTRING *buf = vstring_alloc(100);
1596 const unsigned char *last = start + len - 1;
1597 const unsigned char *row;
1598 const unsigned char *col;
1599 int ch;
1600
1601 #ifdef TRUNCATE_SPACE_NULL
1602 while (last >= start && (*last == ' ' || *last == 0))
1603 last--;
1604 #endif
1605
1606 for (row = start; row <= last; row += DUMP_WIDTH) {
1607 VSTRING_RESET(buf);
1608 vstring_sprintf(buf, "%04lx ", (unsigned long) (row - start));
1609 for (col = row; col < row + DUMP_WIDTH; col++) {
1610 if (col > last) {
1611 vstring_strcat(buf, " ");
1612 } else {
1613 ch = *col;
1614 vstring_sprintf_append(buf, "%02x%c",
1615 ch, col - row == VERT_SPLIT ? '|' : ' ');
1616 }
1617 }
1618 VSTRING_ADDCH(buf, ' ');
1619 for (col = row; col < row + DUMP_WIDTH; col++) {
1620 if (col > last)
1621 break;
1622 ch = *col;
1623 if (!ISPRINT(ch))
1624 ch = '.';
1625 VSTRING_ADDCH(buf, ch);
1626 if (col - row == VERT_SPLIT)
1627 VSTRING_ADDCH(buf, ' ');
1628 }
1629 VSTRING_TERMINATE(buf);
1630 msg_info("%s", vstring_str(buf));
1631 }
1632 #ifdef TRUNCATE_SPACE_NULL
1633 if ((last + 1) - start < len)
1634 msg_info("%04lx - <SPACES/NULLS>",
1635 (unsigned long) ((last + 1) - start));
1636 #endif
1637 vstring_free(buf);
1638 }
1639
1640 /* taken from OpenSSL apps/s_cb.c */
1641
1642 #if !OPENSSL_VERSION_PREREQ(3,0)
tls_bio_dump_cb(BIO * bio,int cmd,const char * argp,int argi,long unused_argl,long ret)1643 long tls_bio_dump_cb(BIO *bio, int cmd, const char *argp, int argi,
1644 long unused_argl, long ret)
1645 {
1646 if (cmd == (BIO_CB_READ | BIO_CB_RETURN)) {
1647 msg_info("read from %08lX [%08lX] (%d bytes => %ld (0x%lX))",
1648 (unsigned long) bio, (unsigned long) argp, argi,
1649 ret, (unsigned long) ret);
1650 tls_dump_buffer((unsigned char *) argp, (int) ret);
1651 } else if (cmd == (BIO_CB_WRITE | BIO_CB_RETURN)) {
1652 msg_info("write to %08lX [%08lX] (%d bytes => %ld (0x%lX))",
1653 (unsigned long) bio, (unsigned long) argp, argi,
1654 ret, (unsigned long) ret);
1655 tls_dump_buffer((unsigned char *) argp, (int) ret);
1656 }
1657 return (ret);
1658 }
1659
1660 #else
tls_bio_dump_cb(BIO * bio,int cmd,const char * argp,size_t len,int argi,long unused_argl,int ret,size_t * processed)1661 long tls_bio_dump_cb(BIO *bio, int cmd, const char *argp, size_t len,
1662 int argi, long unused_argl, int ret, size_t *processed)
1663 {
1664 size_t bytes = (ret > 0 && processed != NULL) ? *processed : len;
1665
1666 if (cmd == (BIO_CB_READ | BIO_CB_RETURN)) {
1667 if (ret > 0) {
1668 msg_info("read from %08lX [%08lX] (%ld bytes => %ld (0x%lX))",
1669 (unsigned long) bio, (unsigned long) argp, (long) len,
1670 (long) bytes, (long) bytes);
1671 tls_dump_buffer((unsigned char *) argp, (int) bytes);
1672 } else {
1673 msg_info("read from %08lX [%08lX] (%ld bytes => %d)",
1674 (unsigned long) bio, (unsigned long) argp,
1675 (long) len, ret);
1676 }
1677 } else if (cmd == (BIO_CB_WRITE | BIO_CB_RETURN)) {
1678 if (ret > 0) {
1679 msg_info("write to %08lX [%08lX] (%ld bytes => %ld (0x%lX))",
1680 (unsigned long) bio, (unsigned long) argp, (long) len,
1681 (long) bytes, (long) bytes);
1682 tls_dump_buffer((unsigned char *) argp, (int) bytes);
1683 } else {
1684 msg_info("write to %08lX [%08lX] (%ld bytes => %d)",
1685 (unsigned long) bio, (unsigned long) argp,
1686 (long) len, ret);
1687 }
1688 }
1689 return ret;
1690 }
1691
1692 #endif
1693
tls_validate_digest(const char * dgst)1694 const EVP_MD *tls_validate_digest(const char *dgst)
1695 {
1696 const EVP_MD *md_alg;
1697
1698 /*
1699 * If the administrator specifies an unsupported digest algorithm, fail
1700 * now, rather than in the middle of a TLS handshake.
1701 */
1702 if ((md_alg = tls_digest_byname(dgst, NULL)) == 0)
1703 msg_warn("Digest algorithm \"%s\" not found", dgst);
1704 return md_alg;
1705 }
1706
1707 #else
1708
1709 /*
1710 * Broken linker workaround.
1711 */
1712 int tls_dummy_for_broken_linkers;
1713
1714 #endif
1715