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Disallow certs with explicit curve in verification chain
[thirdparty/openssl.git] / crypto / x509 / x509_vfy.c
1 /*
2 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <stdio.h>
11 #include <time.h>
12 #include <errno.h>
13 #include <limits.h>
14
15 #include "crypto/ctype.h"
16 #include "internal/cryptlib.h"
17 #include <openssl/crypto.h>
18 #include <openssl/buffer.h>
19 #include <openssl/evp.h>
20 #include <openssl/asn1.h>
21 #include <openssl/x509.h>
22 #include <openssl/x509v3.h>
23 #include <openssl/objects.h>
24 #include "internal/dane.h"
25 #include "crypto/x509.h"
26 #include "x509_local.h"
27
28 /* CRL score values */
29
30 /* No unhandled critical extensions */
31
32 #define CRL_SCORE_NOCRITICAL 0x100
33
34 /* certificate is within CRL scope */
35
36 #define CRL_SCORE_SCOPE 0x080
37
38 /* CRL times valid */
39
40 #define CRL_SCORE_TIME 0x040
41
42 /* Issuer name matches certificate */
43
44 #define CRL_SCORE_ISSUER_NAME 0x020
45
46 /* If this score or above CRL is probably valid */
47
48 #define CRL_SCORE_VALID (CRL_SCORE_NOCRITICAL|CRL_SCORE_TIME|CRL_SCORE_SCOPE)
49
50 /* CRL issuer is certificate issuer */
51
52 #define CRL_SCORE_ISSUER_CERT 0x018
53
54 /* CRL issuer is on certificate path */
55
56 #define CRL_SCORE_SAME_PATH 0x008
57
58 /* CRL issuer matches CRL AKID */
59
60 #define CRL_SCORE_AKID 0x004
61
62 /* Have a delta CRL with valid times */
63
64 #define CRL_SCORE_TIME_DELTA 0x002
65
66 static int build_chain(X509_STORE_CTX *ctx);
67 static int verify_chain(X509_STORE_CTX *ctx);
68 static int dane_verify(X509_STORE_CTX *ctx);
69 static int null_callback(int ok, X509_STORE_CTX *e);
70 static int check_issued(X509_STORE_CTX *ctx, X509 *x, X509 *issuer);
71 static X509 *find_issuer(X509_STORE_CTX *ctx, STACK_OF(X509) *sk, X509 *x);
72 static int check_chain_extensions(X509_STORE_CTX *ctx);
73 static int check_name_constraints(X509_STORE_CTX *ctx);
74 static int check_id(X509_STORE_CTX *ctx);
75 static int check_trust(X509_STORE_CTX *ctx, int num_untrusted);
76 static int check_revocation(X509_STORE_CTX *ctx);
77 static int check_cert(X509_STORE_CTX *ctx);
78 static int check_policy(X509_STORE_CTX *ctx);
79 static int get_issuer_sk(X509 **issuer, X509_STORE_CTX *ctx, X509 *x);
80 static int check_dane_issuer(X509_STORE_CTX *ctx, int depth);
81 static int check_key_level(X509_STORE_CTX *ctx, X509 *cert);
82 static int check_sig_level(X509_STORE_CTX *ctx, X509 *cert);
83 static int check_curve(X509 *cert);
84
85 static int get_crl_score(X509_STORE_CTX *ctx, X509 **pissuer,
86 unsigned int *preasons, X509_CRL *crl, X509 *x);
87 static int get_crl_delta(X509_STORE_CTX *ctx,
88 X509_CRL **pcrl, X509_CRL **pdcrl, X509 *x);
89 static void get_delta_sk(X509_STORE_CTX *ctx, X509_CRL **dcrl,
90 int *pcrl_score, X509_CRL *base,
91 STACK_OF(X509_CRL) *crls);
92 static void crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl, X509 **pissuer,
93 int *pcrl_score);
94 static int crl_crldp_check(X509 *x, X509_CRL *crl, int crl_score,
95 unsigned int *preasons);
96 static int check_crl_path(X509_STORE_CTX *ctx, X509 *x);
97 static int check_crl_chain(X509_STORE_CTX *ctx,
98 STACK_OF(X509) *cert_path,
99 STACK_OF(X509) *crl_path);
100
101 static int internal_verify(X509_STORE_CTX *ctx);
102
103 static int null_callback(int ok, X509_STORE_CTX *e)
104 {
105 return ok;
106 }
107
108 /*-
109 * Return 1 if given cert is considered self-signed, 0 if not, or -1 on error.
110 * This actually verifies self-signedness only if requested.
111 * It calls X509v3_cache_extensions()
112 * to match issuer and subject names (i.e., the cert being self-issued) and any
113 * present authority key identifier to match the subject key identifier, etc.
114 */
115 int X509_self_signed(X509 *cert, int verify_signature)
116 {
117 EVP_PKEY *pkey;
118
119 if ((pkey = X509_get0_pubkey(cert)) == NULL) { /* handles cert == NULL */
120 X509err(0, X509_R_UNABLE_TO_GET_CERTS_PUBLIC_KEY);
121 return -1;
122 }
123 if (!x509v3_cache_extensions(cert))
124 return -1;
125 if ((cert->ex_flags & EXFLAG_SS) == 0)
126 return 0;
127 if (!verify_signature)
128 return 1;
129 return X509_verify(cert, pkey);
130 }
131
132 /* Given a certificate try and find an exact match in the store */
133 static X509 *lookup_cert_match(X509_STORE_CTX *ctx, X509 *x)
134 {
135 STACK_OF(X509) *certs;
136 X509 *xtmp = NULL;
137 int i;
138 /* Lookup all certs with matching subject name */
139 certs = ctx->lookup_certs(ctx, X509_get_subject_name(x));
140 if (certs == NULL)
141 return NULL;
142 /* Look for exact match */
143 for (i = 0; i < sk_X509_num(certs); i++) {
144 xtmp = sk_X509_value(certs, i);
145 if (!X509_cmp(xtmp, x))
146 break;
147 xtmp = NULL;
148 }
149 if (xtmp != NULL && !X509_up_ref(xtmp))
150 xtmp = NULL;
151 sk_X509_pop_free(certs, X509_free);
152 return xtmp;
153 }
154
155 /*-
156 * Inform the verify callback of an error.
157 * If B<x> is not NULL it is the error cert, otherwise use the chain cert at
158 * B<depth>.
159 * If B<err> is not X509_V_OK, that's the error value, otherwise leave
160 * unchanged (presumably set by the caller).
161 *
162 * Returns 0 to abort verification with an error, non-zero to continue.
163 */
164 static int verify_cb_cert(X509_STORE_CTX *ctx, X509 *x, int depth, int err)
165 {
166 ctx->error_depth = depth;
167 ctx->current_cert = (x != NULL) ? x : sk_X509_value(ctx->chain, depth);
168 if (err != X509_V_OK)
169 ctx->error = err;
170 return ctx->verify_cb(0, ctx);
171 }
172
173 /*-
174 * Inform the verify callback of an error, CRL-specific variant. Here, the
175 * error depth and certificate are already set, we just specify the error
176 * number.
177 *
178 * Returns 0 to abort verification with an error, non-zero to continue.
179 */
180 static int verify_cb_crl(X509_STORE_CTX *ctx, int err)
181 {
182 ctx->error = err;
183 return ctx->verify_cb(0, ctx);
184 }
185
186 static int check_auth_level(X509_STORE_CTX *ctx)
187 {
188 int i;
189 int num = sk_X509_num(ctx->chain);
190
191 if (ctx->param->auth_level <= 0)
192 return 1;
193
194 for (i = 0; i < num; ++i) {
195 X509 *cert = sk_X509_value(ctx->chain, i);
196
197 /*
198 * We've already checked the security of the leaf key, so here we only
199 * check the security of issuer keys.
200 */
201 if (i > 0 && !check_key_level(ctx, cert) &&
202 verify_cb_cert(ctx, cert, i, X509_V_ERR_CA_KEY_TOO_SMALL) == 0)
203 return 0;
204 /*
205 * We also check the signature algorithm security of all certificates
206 * except those of the trust anchor at index num-1.
207 */
208 if (i < num - 1 && !check_sig_level(ctx, cert) &&
209 verify_cb_cert(ctx, cert, i, X509_V_ERR_CA_MD_TOO_WEAK) == 0)
210 return 0;
211 }
212 return 1;
213 }
214
215 static int verify_chain(X509_STORE_CTX *ctx)
216 {
217 int err;
218 int ok;
219
220 /*
221 * Before either returning with an error, or continuing with CRL checks,
222 * instantiate chain public key parameters.
223 */
224 if ((ok = build_chain(ctx)) == 0 ||
225 (ok = check_chain_extensions(ctx)) == 0 ||
226 (ok = check_auth_level(ctx)) == 0 ||
227 (ok = check_id(ctx)) == 0 || 1)
228 X509_get_pubkey_parameters(NULL, ctx->chain);
229 if (ok == 0 || (ok = ctx->check_revocation(ctx)) == 0)
230 return ok;
231
232 err = X509_chain_check_suiteb(&ctx->error_depth, NULL, ctx->chain,
233 ctx->param->flags);
234 if (err != X509_V_OK) {
235 if ((ok = verify_cb_cert(ctx, NULL, ctx->error_depth, err)) == 0)
236 return ok;
237 }
238
239 /* Verify chain signatures and expiration times */
240 ok = (ctx->verify != NULL) ? ctx->verify(ctx) : internal_verify(ctx);
241 if (!ok)
242 return ok;
243
244 if ((ok = check_name_constraints(ctx)) == 0)
245 return ok;
246
247 #ifndef OPENSSL_NO_RFC3779
248 /* RFC 3779 path validation, now that CRL check has been done */
249 if ((ok = X509v3_asid_validate_path(ctx)) == 0)
250 return ok;
251 if ((ok = X509v3_addr_validate_path(ctx)) == 0)
252 return ok;
253 #endif
254
255 /* If we get this far evaluate policies */
256 if (ctx->param->flags & X509_V_FLAG_POLICY_CHECK)
257 ok = ctx->check_policy(ctx);
258 return ok;
259 }
260
261 int X509_verify_cert(X509_STORE_CTX *ctx)
262 {
263 SSL_DANE *dane = ctx->dane;
264 int ret;
265
266 if (ctx->cert == NULL) {
267 X509err(X509_F_X509_VERIFY_CERT, X509_R_NO_CERT_SET_FOR_US_TO_VERIFY);
268 ctx->error = X509_V_ERR_INVALID_CALL;
269 return -1;
270 }
271
272 if (ctx->chain != NULL) {
273 /*
274 * This X509_STORE_CTX has already been used to verify a cert. We
275 * cannot do another one.
276 */
277 X509err(X509_F_X509_VERIFY_CERT, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
278 ctx->error = X509_V_ERR_INVALID_CALL;
279 return -1;
280 }
281
282 if (!X509_add_cert_new(&ctx->chain, ctx->cert, X509_ADD_FLAG_UP_REF)) {
283 ctx->error = X509_V_ERR_OUT_OF_MEM;
284 return -1;
285 }
286 ctx->num_untrusted = 1;
287
288 /* If the peer's public key is too weak, we can stop early. */
289 if (!check_key_level(ctx, ctx->cert) &&
290 !verify_cb_cert(ctx, ctx->cert, 0, X509_V_ERR_EE_KEY_TOO_SMALL))
291 return 0;
292
293 if (DANETLS_ENABLED(dane))
294 ret = dane_verify(ctx);
295 else
296 ret = verify_chain(ctx);
297
298 /*
299 * Safety-net. If we are returning an error, we must also set ctx->error,
300 * so that the chain is not considered verified should the error be ignored
301 * (e.g. TLS with SSL_VERIFY_NONE).
302 */
303 if (ret <= 0 && ctx->error == X509_V_OK)
304 ctx->error = X509_V_ERR_UNSPECIFIED;
305 return ret;
306 }
307
308 /*
309 * Given a STACK_OF(X509) find the issuer of cert (if any)
310 */
311 static X509 *find_issuer(X509_STORE_CTX *ctx, STACK_OF(X509) *sk, X509 *x)
312 {
313 int i;
314 X509 *issuer, *rv = NULL;
315
316 for (i = 0; i < sk_X509_num(sk); i++) {
317 issuer = sk_X509_value(sk, i);
318 /*
319 * Below check 'issuer != x' is an optimization and safety precaution:
320 * Candidate issuer cert cannot be the same as the subject cert 'x'.
321 */
322 if (issuer != x && ctx->check_issued(ctx, x, issuer)) {
323 rv = issuer;
324 if (x509_check_cert_time(ctx, rv, -1))
325 break;
326 }
327 }
328 return rv;
329 }
330
331 /*
332 * Check that the given certificate 'x' is issued by the certificate 'issuer'
333 * and the issuer is not yet in ctx->chain, where the exceptional case
334 * that 'x' is self-issued and ctx->chain has just one element is allowed.
335 */
336 static int check_issued(X509_STORE_CTX *ctx, X509 *x, X509 *issuer)
337 {
338 if (x509_likely_issued(issuer, x) != X509_V_OK)
339 return 0;
340 if ((x->ex_flags & EXFLAG_SI) == 0 || sk_X509_num(ctx->chain) != 1) {
341 int i;
342 X509 *ch;
343
344 for (i = 0; i < sk_X509_num(ctx->chain); i++) {
345 ch = sk_X509_value(ctx->chain, i);
346 if (ch == issuer || X509_cmp(ch, issuer) == 0)
347 return 0;
348 }
349 }
350 return 1;
351 }
352
353 /* Alternative lookup method: look from a STACK stored in other_ctx */
354 static int get_issuer_sk(X509 **issuer, X509_STORE_CTX *ctx, X509 *x)
355 {
356 *issuer = find_issuer(ctx, ctx->other_ctx, x);
357
358 if (*issuer == NULL || !X509_up_ref(*issuer))
359 goto err;
360
361 return 1;
362
363 err:
364 *issuer = NULL;
365 return 0;
366 }
367
368 static STACK_OF(X509) *lookup_certs_sk(X509_STORE_CTX *ctx,
369 const X509_NAME *nm)
370 {
371 STACK_OF(X509) *sk = NULL;
372 X509 *x;
373 int i;
374
375 for (i = 0; i < sk_X509_num(ctx->other_ctx); i++) {
376 x = sk_X509_value(ctx->other_ctx, i);
377 if (X509_NAME_cmp(nm, X509_get_subject_name(x)) == 0) {
378 if (!X509_add_cert_new(&sk, x, X509_ADD_FLAG_UP_REF)) {
379 sk_X509_pop_free(sk, X509_free);
380 ctx->error = X509_V_ERR_OUT_OF_MEM;
381 return NULL;
382 }
383 }
384 }
385 return sk;
386 }
387
388 /*
389 * Check EE or CA certificate purpose. For trusted certificates explicit local
390 * auxiliary trust can be used to override EKU-restrictions.
391 */
392 static int check_purpose(X509_STORE_CTX *ctx, X509 *x, int purpose, int depth,
393 int must_be_ca)
394 {
395 int tr_ok = X509_TRUST_UNTRUSTED;
396
397 /*
398 * For trusted certificates we want to see whether any auxiliary trust
399 * settings trump the purpose constraints.
400 *
401 * This is complicated by the fact that the trust ordinals in
402 * ctx->param->trust are entirely independent of the purpose ordinals in
403 * ctx->param->purpose!
404 *
405 * What connects them is their mutual initialization via calls from
406 * X509_STORE_CTX_set_default() into X509_VERIFY_PARAM_lookup() which sets
407 * related values of both param->trust and param->purpose. It is however
408 * typically possible to infer associated trust values from a purpose value
409 * via the X509_PURPOSE API.
410 *
411 * Therefore, we can only check for trust overrides when the purpose we're
412 * checking is the same as ctx->param->purpose and ctx->param->trust is
413 * also set.
414 */
415 if (depth >= ctx->num_untrusted && purpose == ctx->param->purpose)
416 tr_ok = X509_check_trust(x, ctx->param->trust, X509_TRUST_NO_SS_COMPAT);
417
418 switch (tr_ok) {
419 case X509_TRUST_TRUSTED:
420 return 1;
421 case X509_TRUST_REJECTED:
422 break;
423 default:
424 switch (X509_check_purpose(x, purpose, must_be_ca > 0)) {
425 case 1:
426 return 1;
427 case 0:
428 break;
429 default:
430 if ((ctx->param->flags & X509_V_FLAG_X509_STRICT) == 0)
431 return 1;
432 }
433 break;
434 }
435
436 return verify_cb_cert(ctx, x, depth, X509_V_ERR_INVALID_PURPOSE);
437 }
438
439 /*
440 * Check a certificate chains extensions for consistency with the supplied
441 * purpose
442 */
443
444 static int check_chain_extensions(X509_STORE_CTX *ctx)
445 {
446 int i, must_be_ca, plen = 0;
447 X509 *x;
448 int proxy_path_length = 0;
449 int purpose;
450 int allow_proxy_certs;
451 int num = sk_X509_num(ctx->chain);
452
453 /*-
454 * must_be_ca can have 1 of 3 values:
455 * -1: we accept both CA and non-CA certificates, to allow direct
456 * use of self-signed certificates (which are marked as CA).
457 * 0: we only accept non-CA certificates. This is currently not
458 * used, but the possibility is present for future extensions.
459 * 1: we only accept CA certificates. This is currently used for
460 * all certificates in the chain except the leaf certificate.
461 */
462 must_be_ca = -1;
463
464 /* CRL path validation */
465 if (ctx->parent) {
466 allow_proxy_certs = 0;
467 purpose = X509_PURPOSE_CRL_SIGN;
468 } else {
469 allow_proxy_certs =
470 ! !(ctx->param->flags & X509_V_FLAG_ALLOW_PROXY_CERTS);
471 purpose = ctx->param->purpose;
472 }
473
474 for (i = 0; i < num; i++) {
475 int ret;
476
477 x = sk_X509_value(ctx->chain, i);
478 if (!(ctx->param->flags & X509_V_FLAG_IGNORE_CRITICAL)
479 && (x->ex_flags & EXFLAG_CRITICAL)) {
480 if (!verify_cb_cert(ctx, x, i,
481 X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION))
482 return 0;
483 }
484 if (!allow_proxy_certs && (x->ex_flags & EXFLAG_PROXY)) {
485 if (!verify_cb_cert(ctx, x, i,
486 X509_V_ERR_PROXY_CERTIFICATES_NOT_ALLOWED))
487 return 0;
488 }
489 ret = X509_check_ca(x);
490 switch (must_be_ca) {
491 case -1:
492 if ((ctx->param->flags & X509_V_FLAG_X509_STRICT)
493 && (ret != 1) && (ret != 0)) {
494 ret = 0;
495 ctx->error = X509_V_ERR_INVALID_CA;
496 } else
497 ret = 1;
498 break;
499 case 0:
500 if (ret != 0) {
501 ret = 0;
502 ctx->error = X509_V_ERR_INVALID_NON_CA;
503 } else
504 ret = 1;
505 break;
506 default:
507 /* X509_V_FLAG_X509_STRICT is implicit for intermediate CAs */
508 if ((ret == 0)
509 || ((i + 1 < num || ctx->param->flags & X509_V_FLAG_X509_STRICT)
510 && (ret != 1))) {
511 ret = 0;
512 ctx->error = X509_V_ERR_INVALID_CA;
513 } else
514 ret = 1;
515 break;
516 }
517 if (num > 1) {
518 /* Check for presence of explicit elliptic curve parameters */
519 ret = check_curve(x);
520 if (ret < 0)
521 ctx->error = X509_V_ERR_UNSPECIFIED;
522 else if (ret == 0)
523 ctx->error = X509_V_ERR_EC_KEY_EXPLICIT_PARAMS;
524 }
525 /*
526 * Do the following set of checks only if strict checking is requrested
527 * and not for self-issued (including self-signed) EE (non-CA) certs
528 * because RFC 5280 does not apply to them according RFC 6818 section 2.
529 */
530 if ((ctx->param->flags & X509_V_FLAG_X509_STRICT) != 0
531 && num > 1) { /*
532 * this should imply
533 * !(i == 0 && (x->ex_flags & EXFLAG_CA) == 0
534 * && (x->ex_flags & EXFLAG_SI) != 0)
535 */
536 /* Check Basic Constraints according to RFC 5280 section 4.2.1.9 */
537 if (x->ex_pathlen != -1) {
538 if ((x->ex_flags & EXFLAG_CA) == 0)
539 ctx->error = X509_V_ERR_PATHLEN_INVALID_FOR_NON_CA;
540 if ((x->ex_kusage & KU_KEY_CERT_SIGN) == 0)
541 ctx->error = X509_V_ERR_PATHLEN_WITHOUT_KU_KEY_CERT_SIGN;
542 }
543 if ((x->ex_flags & EXFLAG_CA) != 0
544 && (x->ex_flags & EXFLAG_BCONS) != 0
545 && (x->ex_flags & EXFLAG_BCONS_CRITICAL) == 0)
546 ctx->error = X509_V_ERR_CA_BCONS_NOT_CRITICAL;
547 /* Check Key Usage according to RFC 5280 section 4.2.1.3 */
548 if ((x->ex_flags & EXFLAG_CA) != 0) {
549 if ((x->ex_flags & EXFLAG_KUSAGE) == 0)
550 ctx->error = X509_V_ERR_CA_CERT_MISSING_KEY_USAGE;
551 } else {
552 if ((x->ex_kusage & KU_KEY_CERT_SIGN) != 0)
553 ctx->error = X509_V_ERR_KU_KEY_CERT_SIGN_INVALID_FOR_NON_CA;
554 }
555 /* Check issuer is non-empty acc. to RFC 5280 section 4.1.2.4 */
556 if (X509_NAME_entry_count(X509_get_issuer_name(x)) == 0)
557 ctx->error = X509_V_ERR_ISSUER_NAME_EMPTY;
558 /* Check subject is non-empty acc. to RFC 5280 section 4.1.2.6 */
559 if (((x->ex_flags & EXFLAG_CA) != 0
560 || (x->ex_kusage & KU_CRL_SIGN) != 0
561 || x->altname == NULL
562 ) && X509_NAME_entry_count(X509_get_subject_name(x)) == 0)
563 ctx->error = X509_V_ERR_SUBJECT_NAME_EMPTY;
564 if (X509_NAME_entry_count(X509_get_subject_name(x)) == 0
565 && x->altname != NULL
566 && (x->ex_flags & EXFLAG_SAN_CRITICAL) == 0)
567 ctx->error = X509_V_ERR_EMPTY_SUBJECT_SAN_NOT_CRITICAL;
568 /* Check SAN is non-empty according to RFC 5280 section 4.2.1.6 */
569 if (x->altname != NULL && sk_GENERAL_NAME_num(x->altname) <= 0)
570 ctx->error = X509_V_ERR_EMPTY_SUBJECT_ALT_NAME;
571 /* TODO add more checks on SAN entries */
572 /* Check sig alg consistency acc. to RFC 5280 section 4.1.1.2 */
573 if (X509_ALGOR_cmp(&x->sig_alg, &x->cert_info.signature) != 0)
574 ctx->error = X509_V_ERR_SIGNATURE_ALGORITHM_INCONSISTENCY;
575 if (x->akid != NULL && (x->ex_flags & EXFLAG_AKID_CRITICAL) != 0)
576 ctx->error = X509_V_ERR_AUTHORITY_KEY_IDENTIFIER_CRITICAL;
577 if (x->skid != NULL && (x->ex_flags & EXFLAG_SKID_CRITICAL) != 0)
578 ctx->error = X509_V_ERR_SUBJECT_KEY_IDENTIFIER_CRITICAL;
579 if (X509_get_version(x) >= 2) { /* at least X.509v3 */
580 /* Check AKID presence acc. to RFC 5280 section 4.2.1.1 */
581 if (i + 1 < num /*
582 * this means not last cert in chain,
583 * taken as "generated by conforming CAs"
584 */
585 && (x->akid == NULL || x->akid->keyid == NULL))
586 ctx->error = X509_V_ERR_MISSING_AUTHORITY_KEY_IDENTIFIER;
587 /* Check SKID presence acc. to RFC 5280 section 4.2.1.2 */
588 if ((x->ex_flags & EXFLAG_CA) != 0 && x->skid == NULL)
589 ctx->error = X509_V_ERR_MISSING_SUBJECT_KEY_IDENTIFIER;
590 } else {
591 if (sk_X509_EXTENSION_num(X509_get0_extensions(x)) > 0)
592 ctx->error = X509_V_ERR_EXTENSIONS_REQUIRE_VERSION_3;
593 }
594 }
595 if (ctx->error != X509_V_OK)
596 ret = 0;
597 if (ret == 0 && !verify_cb_cert(ctx, x, i, X509_V_OK))
598 return 0;
599 /* check_purpose() makes the callback as needed */
600 if (purpose > 0 && !check_purpose(ctx, x, purpose, i, must_be_ca))
601 return 0;
602 /* Check pathlen */
603 if ((i > 1) && (x->ex_pathlen != -1)
604 && (plen > (x->ex_pathlen + proxy_path_length))) {
605 if (!verify_cb_cert(ctx, x, i, X509_V_ERR_PATH_LENGTH_EXCEEDED))
606 return 0;
607 }
608 /* Increment path length if not a self-issued intermediate CA */
609 if (i > 0 && (x->ex_flags & EXFLAG_SI) == 0)
610 plen++;
611 /*
612 * If this certificate is a proxy certificate, the next certificate
613 * must be another proxy certificate or a EE certificate. If not,
614 * the next certificate must be a CA certificate.
615 */
616 if (x->ex_flags & EXFLAG_PROXY) {
617 /*
618 * RFC3820, 4.1.3 (b)(1) stipulates that if pCPathLengthConstraint
619 * is less than max_path_length, the former should be copied to
620 * the latter, and 4.1.4 (a) stipulates that max_path_length
621 * should be verified to be larger than zero and decrement it.
622 *
623 * Because we're checking the certs in the reverse order, we start
624 * with verifying that proxy_path_length isn't larger than pcPLC,
625 * and copy the latter to the former if it is, and finally,
626 * increment proxy_path_length.
627 */
628 if (x->ex_pcpathlen != -1) {
629 if (proxy_path_length > x->ex_pcpathlen) {
630 if (!verify_cb_cert(ctx, x, i,
631 X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED))
632 return 0;
633 }
634 proxy_path_length = x->ex_pcpathlen;
635 }
636 proxy_path_length++;
637 must_be_ca = 0;
638 } else
639 must_be_ca = 1;
640 }
641 return 1;
642 }
643
644 static int has_san_id(X509 *x, int gtype)
645 {
646 int i;
647 int ret = 0;
648 GENERAL_NAMES *gs = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
649
650 if (gs == NULL)
651 return 0;
652
653 for (i = 0; i < sk_GENERAL_NAME_num(gs); i++) {
654 GENERAL_NAME *g = sk_GENERAL_NAME_value(gs, i);
655
656 if (g->type == gtype) {
657 ret = 1;
658 break;
659 }
660 }
661 GENERAL_NAMES_free(gs);
662 return ret;
663 }
664
665 static int check_name_constraints(X509_STORE_CTX *ctx)
666 {
667 int i;
668
669 /* Check name constraints for all certificates */
670 for (i = sk_X509_num(ctx->chain) - 1; i >= 0; i--) {
671 X509 *x = sk_X509_value(ctx->chain, i);
672 int j;
673
674 /* Ignore self-issued certs unless last in chain */
675 if (i && (x->ex_flags & EXFLAG_SI))
676 continue;
677
678 /*
679 * Proxy certificates policy has an extra constraint, where the
680 * certificate subject MUST be the issuer with a single CN entry
681 * added.
682 * (RFC 3820: 3.4, 4.1.3 (a)(4))
683 */
684 if (x->ex_flags & EXFLAG_PROXY) {
685 X509_NAME *tmpsubject = X509_get_subject_name(x);
686 X509_NAME *tmpissuer = X509_get_issuer_name(x);
687 X509_NAME_ENTRY *tmpentry = NULL;
688 int last_object_nid = 0;
689 int err = X509_V_OK;
690 int last_object_loc = X509_NAME_entry_count(tmpsubject) - 1;
691
692 /* Check that there are at least two RDNs */
693 if (last_object_loc < 1) {
694 err = X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION;
695 goto proxy_name_done;
696 }
697
698 /*
699 * Check that there is exactly one more RDN in subject as
700 * there is in issuer.
701 */
702 if (X509_NAME_entry_count(tmpsubject)
703 != X509_NAME_entry_count(tmpissuer) + 1) {
704 err = X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION;
705 goto proxy_name_done;
706 }
707
708 /*
709 * Check that the last subject component isn't part of a
710 * multivalued RDN
711 */
712 if (X509_NAME_ENTRY_set(X509_NAME_get_entry(tmpsubject,
713 last_object_loc))
714 == X509_NAME_ENTRY_set(X509_NAME_get_entry(tmpsubject,
715 last_object_loc - 1))) {
716 err = X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION;
717 goto proxy_name_done;
718 }
719
720 /*
721 * Check that the last subject RDN is a commonName, and that
722 * all the previous RDNs match the issuer exactly
723 */
724 tmpsubject = X509_NAME_dup(tmpsubject);
725 if (tmpsubject == NULL) {
726 X509err(X509_F_CHECK_NAME_CONSTRAINTS, ERR_R_MALLOC_FAILURE);
727 ctx->error = X509_V_ERR_OUT_OF_MEM;
728 return 0;
729 }
730
731 tmpentry =
732 X509_NAME_delete_entry(tmpsubject, last_object_loc);
733 last_object_nid =
734 OBJ_obj2nid(X509_NAME_ENTRY_get_object(tmpentry));
735
736 if (last_object_nid != NID_commonName
737 || X509_NAME_cmp(tmpsubject, tmpissuer) != 0) {
738 err = X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION;
739 }
740
741 X509_NAME_ENTRY_free(tmpentry);
742 X509_NAME_free(tmpsubject);
743
744 proxy_name_done:
745 if (err != X509_V_OK
746 && !verify_cb_cert(ctx, x, i, err))
747 return 0;
748 }
749
750 /*
751 * Check against constraints for all certificates higher in chain
752 * including trust anchor. Trust anchor not strictly speaking needed
753 * but if it includes constraints it is to be assumed it expects them
754 * to be obeyed.
755 */
756 for (j = sk_X509_num(ctx->chain) - 1; j > i; j--) {
757 NAME_CONSTRAINTS *nc = sk_X509_value(ctx->chain, j)->nc;
758
759 if (nc) {
760 int rv = NAME_CONSTRAINTS_check(x, nc);
761
762 /* If EE certificate check commonName too */
763 if (rv == X509_V_OK && i == 0
764 && (ctx->param->hostflags
765 & X509_CHECK_FLAG_NEVER_CHECK_SUBJECT) == 0
766 && ((ctx->param->hostflags
767 & X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT) != 0
768 || !has_san_id(x, GEN_DNS)))
769 rv = NAME_CONSTRAINTS_check_CN(x, nc);
770
771 switch (rv) {
772 case X509_V_OK:
773 break;
774 case X509_V_ERR_OUT_OF_MEM:
775 return 0;
776 default:
777 if (!verify_cb_cert(ctx, x, i, rv))
778 return 0;
779 break;
780 }
781 }
782 }
783 }
784 return 1;
785 }
786
787 static int check_id_error(X509_STORE_CTX *ctx, int errcode)
788 {
789 return verify_cb_cert(ctx, ctx->cert, 0, errcode);
790 }
791
792 static int check_hosts(X509 *x, X509_VERIFY_PARAM *vpm)
793 {
794 int i;
795 int n = sk_OPENSSL_STRING_num(vpm->hosts);
796 char *name;
797
798 if (vpm->peername != NULL) {
799 OPENSSL_free(vpm->peername);
800 vpm->peername = NULL;
801 }
802 for (i = 0; i < n; ++i) {
803 name = sk_OPENSSL_STRING_value(vpm->hosts, i);
804 if (X509_check_host(x, name, 0, vpm->hostflags, &vpm->peername) > 0)
805 return 1;
806 }
807 return n == 0;
808 }
809
810 static int check_id(X509_STORE_CTX *ctx)
811 {
812 X509_VERIFY_PARAM *vpm = ctx->param;
813 X509 *x = ctx->cert;
814 if (vpm->hosts && check_hosts(x, vpm) <= 0) {
815 if (!check_id_error(ctx, X509_V_ERR_HOSTNAME_MISMATCH))
816 return 0;
817 }
818 if (vpm->email && X509_check_email(x, vpm->email, vpm->emaillen, 0) <= 0) {
819 if (!check_id_error(ctx, X509_V_ERR_EMAIL_MISMATCH))
820 return 0;
821 }
822 if (vpm->ip && X509_check_ip(x, vpm->ip, vpm->iplen, 0) <= 0) {
823 if (!check_id_error(ctx, X509_V_ERR_IP_ADDRESS_MISMATCH))
824 return 0;
825 }
826 return 1;
827 }
828
829 static int check_trust(X509_STORE_CTX *ctx, int num_untrusted)
830 {
831 int i;
832 X509 *x = NULL;
833 X509 *mx;
834 SSL_DANE *dane = ctx->dane;
835 int num = sk_X509_num(ctx->chain);
836 int trust;
837
838 /*
839 * Check for a DANE issuer at depth 1 or greater, if it is a DANE-TA(2)
840 * match, we're done, otherwise we'll merely record the match depth.
841 */
842 if (DANETLS_HAS_TA(dane) && num_untrusted > 0 && num_untrusted < num) {
843 switch (trust = check_dane_issuer(ctx, num_untrusted)) {
844 case X509_TRUST_TRUSTED:
845 case X509_TRUST_REJECTED:
846 return trust;
847 }
848 }
849
850 /*
851 * Check trusted certificates in chain at depth num_untrusted and up.
852 * Note, that depths 0..num_untrusted-1 may also contain trusted
853 * certificates, but the caller is expected to have already checked those,
854 * and wants to incrementally check just any added since.
855 */
856 for (i = num_untrusted; i < num; i++) {
857 x = sk_X509_value(ctx->chain, i);
858 trust = X509_check_trust(x, ctx->param->trust, 0);
859 /* If explicitly trusted return trusted */
860 if (trust == X509_TRUST_TRUSTED)
861 goto trusted;
862 if (trust == X509_TRUST_REJECTED)
863 goto rejected;
864 }
865
866 /*
867 * If we are looking at a trusted certificate, and accept partial chains,
868 * the chain is PKIX trusted.
869 */
870 if (num_untrusted < num) {
871 if (ctx->param->flags & X509_V_FLAG_PARTIAL_CHAIN)
872 goto trusted;
873 return X509_TRUST_UNTRUSTED;
874 }
875
876 if (num_untrusted == num && ctx->param->flags & X509_V_FLAG_PARTIAL_CHAIN) {
877 /*
878 * Last-resort call with no new trusted certificates, check the leaf
879 * for a direct trust store match.
880 */
881 i = 0;
882 x = sk_X509_value(ctx->chain, i);
883 mx = lookup_cert_match(ctx, x);
884 if (!mx)
885 return X509_TRUST_UNTRUSTED;
886
887 /*
888 * Check explicit auxiliary trust/reject settings. If none are set,
889 * we'll accept X509_TRUST_UNTRUSTED when not self-signed.
890 */
891 trust = X509_check_trust(mx, ctx->param->trust, 0);
892 if (trust == X509_TRUST_REJECTED) {
893 X509_free(mx);
894 goto rejected;
895 }
896
897 /* Replace leaf with trusted match */
898 (void) sk_X509_set(ctx->chain, 0, mx);
899 X509_free(x);
900 ctx->num_untrusted = 0;
901 goto trusted;
902 }
903
904 /*
905 * If no trusted certs in chain at all return untrusted and allow
906 * standard (no issuer cert) etc errors to be indicated.
907 */
908 return X509_TRUST_UNTRUSTED;
909
910 rejected:
911 if (!verify_cb_cert(ctx, x, i, X509_V_ERR_CERT_REJECTED))
912 return X509_TRUST_REJECTED;
913 return X509_TRUST_UNTRUSTED;
914
915 trusted:
916 if (!DANETLS_ENABLED(dane))
917 return X509_TRUST_TRUSTED;
918 if (dane->pdpth < 0)
919 dane->pdpth = num_untrusted;
920 /* With DANE, PKIX alone is not trusted until we have both */
921 if (dane->mdpth >= 0)
922 return X509_TRUST_TRUSTED;
923 return X509_TRUST_UNTRUSTED;
924 }
925
926 static int check_revocation(X509_STORE_CTX *ctx)
927 {
928 int i = 0, last = 0, ok = 0;
929 if (!(ctx->param->flags & X509_V_FLAG_CRL_CHECK))
930 return 1;
931 if (ctx->param->flags & X509_V_FLAG_CRL_CHECK_ALL)
932 last = sk_X509_num(ctx->chain) - 1;
933 else {
934 /* If checking CRL paths this isn't the EE certificate */
935 if (ctx->parent)
936 return 1;
937 last = 0;
938 }
939 for (i = 0; i <= last; i++) {
940 ctx->error_depth = i;
941 ok = check_cert(ctx);
942 if (!ok)
943 return ok;
944 }
945 return 1;
946 }
947
948 static int check_cert(X509_STORE_CTX *ctx)
949 {
950 X509_CRL *crl = NULL, *dcrl = NULL;
951 int ok = 0;
952 int cnum = ctx->error_depth;
953 X509 *x = sk_X509_value(ctx->chain, cnum);
954
955 ctx->current_cert = x;
956 ctx->current_issuer = NULL;
957 ctx->current_crl_score = 0;
958 ctx->current_reasons = 0;
959
960 if (x->ex_flags & EXFLAG_PROXY)
961 return 1;
962
963 while (ctx->current_reasons != CRLDP_ALL_REASONS) {
964 unsigned int last_reasons = ctx->current_reasons;
965
966 /* Try to retrieve relevant CRL */
967 if (ctx->get_crl)
968 ok = ctx->get_crl(ctx, &crl, x);
969 else
970 ok = get_crl_delta(ctx, &crl, &dcrl, x);
971 /*
972 * If error looking up CRL, nothing we can do except notify callback
973 */
974 if (!ok) {
975 ok = verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL);
976 goto done;
977 }
978 ctx->current_crl = crl;
979 ok = ctx->check_crl(ctx, crl);
980 if (!ok)
981 goto done;
982
983 if (dcrl) {
984 ok = ctx->check_crl(ctx, dcrl);
985 if (!ok)
986 goto done;
987 ok = ctx->cert_crl(ctx, dcrl, x);
988 if (!ok)
989 goto done;
990 } else
991 ok = 1;
992
993 /* Don't look in full CRL if delta reason is removefromCRL */
994 if (ok != 2) {
995 ok = ctx->cert_crl(ctx, crl, x);
996 if (!ok)
997 goto done;
998 }
999
1000 X509_CRL_free(crl);
1001 X509_CRL_free(dcrl);
1002 crl = NULL;
1003 dcrl = NULL;
1004 /*
1005 * If reasons not updated we won't get anywhere by another iteration,
1006 * so exit loop.
1007 */
1008 if (last_reasons == ctx->current_reasons) {
1009 ok = verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL);
1010 goto done;
1011 }
1012 }
1013 done:
1014 X509_CRL_free(crl);
1015 X509_CRL_free(dcrl);
1016
1017 ctx->current_crl = NULL;
1018 return ok;
1019 }
1020
1021 /* Check CRL times against values in X509_STORE_CTX */
1022
1023 static int check_crl_time(X509_STORE_CTX *ctx, X509_CRL *crl, int notify)
1024 {
1025 time_t *ptime;
1026 int i;
1027
1028 if (notify)
1029 ctx->current_crl = crl;
1030 if (ctx->param->flags & X509_V_FLAG_USE_CHECK_TIME)
1031 ptime = &ctx->param->check_time;
1032 else if (ctx->param->flags & X509_V_FLAG_NO_CHECK_TIME)
1033 return 1;
1034 else
1035 ptime = NULL;
1036
1037 i = X509_cmp_time(X509_CRL_get0_lastUpdate(crl), ptime);
1038 if (i == 0) {
1039 if (!notify)
1040 return 0;
1041 if (!verify_cb_crl(ctx, X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD))
1042 return 0;
1043 }
1044
1045 if (i > 0) {
1046 if (!notify)
1047 return 0;
1048 if (!verify_cb_crl(ctx, X509_V_ERR_CRL_NOT_YET_VALID))
1049 return 0;
1050 }
1051
1052 if (X509_CRL_get0_nextUpdate(crl)) {
1053 i = X509_cmp_time(X509_CRL_get0_nextUpdate(crl), ptime);
1054
1055 if (i == 0) {
1056 if (!notify)
1057 return 0;
1058 if (!verify_cb_crl(ctx, X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD))
1059 return 0;
1060 }
1061 /* Ignore expiry of base CRL is delta is valid */
1062 if ((i < 0) && !(ctx->current_crl_score & CRL_SCORE_TIME_DELTA)) {
1063 if (!notify)
1064 return 0;
1065 if (!verify_cb_crl(ctx, X509_V_ERR_CRL_HAS_EXPIRED))
1066 return 0;
1067 }
1068 }
1069
1070 if (notify)
1071 ctx->current_crl = NULL;
1072
1073 return 1;
1074 }
1075
1076 static int get_crl_sk(X509_STORE_CTX *ctx, X509_CRL **pcrl, X509_CRL **pdcrl,
1077 X509 **pissuer, int *pscore, unsigned int *preasons,
1078 STACK_OF(X509_CRL) *crls)
1079 {
1080 int i, crl_score, best_score = *pscore;
1081 unsigned int reasons, best_reasons = 0;
1082 X509 *x = ctx->current_cert;
1083 X509_CRL *crl, *best_crl = NULL;
1084 X509 *crl_issuer = NULL, *best_crl_issuer = NULL;
1085
1086 for (i = 0; i < sk_X509_CRL_num(crls); i++) {
1087 crl = sk_X509_CRL_value(crls, i);
1088 reasons = *preasons;
1089 crl_score = get_crl_score(ctx, &crl_issuer, &reasons, crl, x);
1090 if (crl_score < best_score || crl_score == 0)
1091 continue;
1092 /* If current CRL is equivalent use it if it is newer */
1093 if (crl_score == best_score && best_crl != NULL) {
1094 int day, sec;
1095 if (ASN1_TIME_diff(&day, &sec, X509_CRL_get0_lastUpdate(best_crl),
1096 X509_CRL_get0_lastUpdate(crl)) == 0)
1097 continue;
1098 /*
1099 * ASN1_TIME_diff never returns inconsistent signs for |day|
1100 * and |sec|.
1101 */
1102 if (day <= 0 && sec <= 0)
1103 continue;
1104 }
1105 best_crl = crl;
1106 best_crl_issuer = crl_issuer;
1107 best_score = crl_score;
1108 best_reasons = reasons;
1109 }
1110
1111 if (best_crl) {
1112 X509_CRL_free(*pcrl);
1113 *pcrl = best_crl;
1114 *pissuer = best_crl_issuer;
1115 *pscore = best_score;
1116 *preasons = best_reasons;
1117 X509_CRL_up_ref(best_crl);
1118 X509_CRL_free(*pdcrl);
1119 *pdcrl = NULL;
1120 get_delta_sk(ctx, pdcrl, pscore, best_crl, crls);
1121 }
1122
1123 if (best_score >= CRL_SCORE_VALID)
1124 return 1;
1125
1126 return 0;
1127 }
1128
1129 /*
1130 * Compare two CRL extensions for delta checking purposes. They should be
1131 * both present or both absent. If both present all fields must be identical.
1132 */
1133
1134 static int crl_extension_match(X509_CRL *a, X509_CRL *b, int nid)
1135 {
1136 ASN1_OCTET_STRING *exta, *extb;
1137 int i;
1138 i = X509_CRL_get_ext_by_NID(a, nid, -1);
1139 if (i >= 0) {
1140 /* Can't have multiple occurrences */
1141 if (X509_CRL_get_ext_by_NID(a, nid, i) != -1)
1142 return 0;
1143 exta = X509_EXTENSION_get_data(X509_CRL_get_ext(a, i));
1144 } else
1145 exta = NULL;
1146
1147 i = X509_CRL_get_ext_by_NID(b, nid, -1);
1148
1149 if (i >= 0) {
1150
1151 if (X509_CRL_get_ext_by_NID(b, nid, i) != -1)
1152 return 0;
1153 extb = X509_EXTENSION_get_data(X509_CRL_get_ext(b, i));
1154 } else
1155 extb = NULL;
1156
1157 if (!exta && !extb)
1158 return 1;
1159
1160 if (!exta || !extb)
1161 return 0;
1162
1163 if (ASN1_OCTET_STRING_cmp(exta, extb))
1164 return 0;
1165
1166 return 1;
1167 }
1168
1169 /* See if a base and delta are compatible */
1170
1171 static int check_delta_base(X509_CRL *delta, X509_CRL *base)
1172 {
1173 /* Delta CRL must be a delta */
1174 if (!delta->base_crl_number)
1175 return 0;
1176 /* Base must have a CRL number */
1177 if (!base->crl_number)
1178 return 0;
1179 /* Issuer names must match */
1180 if (X509_NAME_cmp(X509_CRL_get_issuer(base), X509_CRL_get_issuer(delta)))
1181 return 0;
1182 /* AKID and IDP must match */
1183 if (!crl_extension_match(delta, base, NID_authority_key_identifier))
1184 return 0;
1185 if (!crl_extension_match(delta, base, NID_issuing_distribution_point))
1186 return 0;
1187 /* Delta CRL base number must not exceed Full CRL number. */
1188 if (ASN1_INTEGER_cmp(delta->base_crl_number, base->crl_number) > 0)
1189 return 0;
1190 /* Delta CRL number must exceed full CRL number */
1191 if (ASN1_INTEGER_cmp(delta->crl_number, base->crl_number) > 0)
1192 return 1;
1193 return 0;
1194 }
1195
1196 /*
1197 * For a given base CRL find a delta... maybe extend to delta scoring or
1198 * retrieve a chain of deltas...
1199 */
1200
1201 static void get_delta_sk(X509_STORE_CTX *ctx, X509_CRL **dcrl, int *pscore,
1202 X509_CRL *base, STACK_OF(X509_CRL) *crls)
1203 {
1204 X509_CRL *delta;
1205 int i;
1206 if (!(ctx->param->flags & X509_V_FLAG_USE_DELTAS))
1207 return;
1208 if (!((ctx->current_cert->ex_flags | base->flags) & EXFLAG_FRESHEST))
1209 return;
1210 for (i = 0; i < sk_X509_CRL_num(crls); i++) {
1211 delta = sk_X509_CRL_value(crls, i);
1212 if (check_delta_base(delta, base)) {
1213 if (check_crl_time(ctx, delta, 0))
1214 *pscore |= CRL_SCORE_TIME_DELTA;
1215 X509_CRL_up_ref(delta);
1216 *dcrl = delta;
1217 return;
1218 }
1219 }
1220 *dcrl = NULL;
1221 }
1222
1223 /*
1224 * For a given CRL return how suitable it is for the supplied certificate
1225 * 'x'. The return value is a mask of several criteria. If the issuer is not
1226 * the certificate issuer this is returned in *pissuer. The reasons mask is
1227 * also used to determine if the CRL is suitable: if no new reasons the CRL
1228 * is rejected, otherwise reasons is updated.
1229 */
1230
1231 static int get_crl_score(X509_STORE_CTX *ctx, X509 **pissuer,
1232 unsigned int *preasons, X509_CRL *crl, X509 *x)
1233 {
1234
1235 int crl_score = 0;
1236 unsigned int tmp_reasons = *preasons, crl_reasons;
1237
1238 /* First see if we can reject CRL straight away */
1239
1240 /* Invalid IDP cannot be processed */
1241 if (crl->idp_flags & IDP_INVALID)
1242 return 0;
1243 /* Reason codes or indirect CRLs need extended CRL support */
1244 if (!(ctx->param->flags & X509_V_FLAG_EXTENDED_CRL_SUPPORT)) {
1245 if (crl->idp_flags & (IDP_INDIRECT | IDP_REASONS))
1246 return 0;
1247 } else if (crl->idp_flags & IDP_REASONS) {
1248 /* If no new reasons reject */
1249 if (!(crl->idp_reasons & ~tmp_reasons))
1250 return 0;
1251 }
1252 /* Don't process deltas at this stage */
1253 else if (crl->base_crl_number)
1254 return 0;
1255 /* If issuer name doesn't match certificate need indirect CRL */
1256 if (X509_NAME_cmp(X509_get_issuer_name(x), X509_CRL_get_issuer(crl))) {
1257 if (!(crl->idp_flags & IDP_INDIRECT))
1258 return 0;
1259 } else
1260 crl_score |= CRL_SCORE_ISSUER_NAME;
1261
1262 if (!(crl->flags & EXFLAG_CRITICAL))
1263 crl_score |= CRL_SCORE_NOCRITICAL;
1264
1265 /* Check expiry */
1266 if (check_crl_time(ctx, crl, 0))
1267 crl_score |= CRL_SCORE_TIME;
1268
1269 /* Check authority key ID and locate certificate issuer */
1270 crl_akid_check(ctx, crl, pissuer, &crl_score);
1271
1272 /* If we can't locate certificate issuer at this point forget it */
1273
1274 if (!(crl_score & CRL_SCORE_AKID))
1275 return 0;
1276
1277 /* Check cert for matching CRL distribution points */
1278
1279 if (crl_crldp_check(x, crl, crl_score, &crl_reasons)) {
1280 /* If no new reasons reject */
1281 if (!(crl_reasons & ~tmp_reasons))
1282 return 0;
1283 tmp_reasons |= crl_reasons;
1284 crl_score |= CRL_SCORE_SCOPE;
1285 }
1286
1287 *preasons = tmp_reasons;
1288
1289 return crl_score;
1290
1291 }
1292
1293 static void crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl,
1294 X509 **pissuer, int *pcrl_score)
1295 {
1296 X509 *crl_issuer = NULL;
1297 const X509_NAME *cnm = X509_CRL_get_issuer(crl);
1298 int cidx = ctx->error_depth;
1299 int i;
1300
1301 if (cidx != sk_X509_num(ctx->chain) - 1)
1302 cidx++;
1303
1304 crl_issuer = sk_X509_value(ctx->chain, cidx);
1305
1306 if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK) {
1307 if (*pcrl_score & CRL_SCORE_ISSUER_NAME) {
1308 *pcrl_score |= CRL_SCORE_AKID | CRL_SCORE_ISSUER_CERT;
1309 *pissuer = crl_issuer;
1310 return;
1311 }
1312 }
1313
1314 for (cidx++; cidx < sk_X509_num(ctx->chain); cidx++) {
1315 crl_issuer = sk_X509_value(ctx->chain, cidx);
1316 if (X509_NAME_cmp(X509_get_subject_name(crl_issuer), cnm))
1317 continue;
1318 if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK) {
1319 *pcrl_score |= CRL_SCORE_AKID | CRL_SCORE_SAME_PATH;
1320 *pissuer = crl_issuer;
1321 return;
1322 }
1323 }
1324
1325 /* Anything else needs extended CRL support */
1326
1327 if (!(ctx->param->flags & X509_V_FLAG_EXTENDED_CRL_SUPPORT))
1328 return;
1329
1330 /*
1331 * Otherwise the CRL issuer is not on the path. Look for it in the set of
1332 * untrusted certificates.
1333 */
1334 for (i = 0; i < sk_X509_num(ctx->untrusted); i++) {
1335 crl_issuer = sk_X509_value(ctx->untrusted, i);
1336 if (X509_NAME_cmp(X509_get_subject_name(crl_issuer), cnm))
1337 continue;
1338 if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK) {
1339 *pissuer = crl_issuer;
1340 *pcrl_score |= CRL_SCORE_AKID;
1341 return;
1342 }
1343 }
1344 }
1345
1346 /*
1347 * Check the path of a CRL issuer certificate. This creates a new
1348 * X509_STORE_CTX and populates it with most of the parameters from the
1349 * parent. This could be optimised somewhat since a lot of path checking will
1350 * be duplicated by the parent, but this will rarely be used in practice.
1351 */
1352
1353 static int check_crl_path(X509_STORE_CTX *ctx, X509 *x)
1354 {
1355 X509_STORE_CTX crl_ctx;
1356 int ret;
1357
1358 /* Don't allow recursive CRL path validation */
1359 if (ctx->parent)
1360 return 0;
1361 if (!X509_STORE_CTX_init(&crl_ctx, ctx->store, x, ctx->untrusted))
1362 return -1;
1363
1364 crl_ctx.crls = ctx->crls;
1365 /* Copy verify params across */
1366 X509_STORE_CTX_set0_param(&crl_ctx, ctx->param);
1367
1368 crl_ctx.parent = ctx;
1369 crl_ctx.verify_cb = ctx->verify_cb;
1370
1371 /* Verify CRL issuer */
1372 ret = X509_verify_cert(&crl_ctx);
1373 if (ret <= 0)
1374 goto err;
1375
1376 /* Check chain is acceptable */
1377 ret = check_crl_chain(ctx, ctx->chain, crl_ctx.chain);
1378 err:
1379 X509_STORE_CTX_cleanup(&crl_ctx);
1380 return ret;
1381 }
1382
1383 /*
1384 * RFC3280 says nothing about the relationship between CRL path and
1385 * certificate path, which could lead to situations where a certificate could
1386 * be revoked or validated by a CA not authorised to do so. RFC5280 is more
1387 * strict and states that the two paths must end in the same trust anchor,
1388 * though some discussions remain... until this is resolved we use the
1389 * RFC5280 version
1390 */
1391
1392 static int check_crl_chain(X509_STORE_CTX *ctx,
1393 STACK_OF(X509) *cert_path,
1394 STACK_OF(X509) *crl_path)
1395 {
1396 X509 *cert_ta, *crl_ta;
1397 cert_ta = sk_X509_value(cert_path, sk_X509_num(cert_path) - 1);
1398 crl_ta = sk_X509_value(crl_path, sk_X509_num(crl_path) - 1);
1399 if (!X509_cmp(cert_ta, crl_ta))
1400 return 1;
1401 return 0;
1402 }
1403
1404 /*-
1405 * Check for match between two dist point names: three separate cases.
1406 * 1. Both are relative names and compare X509_NAME types.
1407 * 2. One full, one relative. Compare X509_NAME to GENERAL_NAMES.
1408 * 3. Both are full names and compare two GENERAL_NAMES.
1409 * 4. One is NULL: automatic match.
1410 */
1411
1412 static int idp_check_dp(DIST_POINT_NAME *a, DIST_POINT_NAME *b)
1413 {
1414 X509_NAME *nm = NULL;
1415 GENERAL_NAMES *gens = NULL;
1416 GENERAL_NAME *gena, *genb;
1417 int i, j;
1418 if (!a || !b)
1419 return 1;
1420 if (a->type == 1) {
1421 if (!a->dpname)
1422 return 0;
1423 /* Case 1: two X509_NAME */
1424 if (b->type == 1) {
1425 if (!b->dpname)
1426 return 0;
1427 if (!X509_NAME_cmp(a->dpname, b->dpname))
1428 return 1;
1429 else
1430 return 0;
1431 }
1432 /* Case 2: set name and GENERAL_NAMES appropriately */
1433 nm = a->dpname;
1434 gens = b->name.fullname;
1435 } else if (b->type == 1) {
1436 if (!b->dpname)
1437 return 0;
1438 /* Case 2: set name and GENERAL_NAMES appropriately */
1439 gens = a->name.fullname;
1440 nm = b->dpname;
1441 }
1442
1443 /* Handle case 2 with one GENERAL_NAMES and one X509_NAME */
1444 if (nm) {
1445 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
1446 gena = sk_GENERAL_NAME_value(gens, i);
1447 if (gena->type != GEN_DIRNAME)
1448 continue;
1449 if (!X509_NAME_cmp(nm, gena->d.directoryName))
1450 return 1;
1451 }
1452 return 0;
1453 }
1454
1455 /* Else case 3: two GENERAL_NAMES */
1456
1457 for (i = 0; i < sk_GENERAL_NAME_num(a->name.fullname); i++) {
1458 gena = sk_GENERAL_NAME_value(a->name.fullname, i);
1459 for (j = 0; j < sk_GENERAL_NAME_num(b->name.fullname); j++) {
1460 genb = sk_GENERAL_NAME_value(b->name.fullname, j);
1461 if (!GENERAL_NAME_cmp(gena, genb))
1462 return 1;
1463 }
1464 }
1465
1466 return 0;
1467
1468 }
1469
1470 static int crldp_check_crlissuer(DIST_POINT *dp, X509_CRL *crl, int crl_score)
1471 {
1472 int i;
1473 const X509_NAME *nm = X509_CRL_get_issuer(crl);
1474 /* If no CRLissuer return is successful iff don't need a match */
1475 if (!dp->CRLissuer)
1476 return ! !(crl_score & CRL_SCORE_ISSUER_NAME);
1477 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) {
1478 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
1479 if (gen->type != GEN_DIRNAME)
1480 continue;
1481 if (!X509_NAME_cmp(gen->d.directoryName, nm))
1482 return 1;
1483 }
1484 return 0;
1485 }
1486
1487 /* Check CRLDP and IDP */
1488
1489 static int crl_crldp_check(X509 *x, X509_CRL *crl, int crl_score,
1490 unsigned int *preasons)
1491 {
1492 int i;
1493 if (crl->idp_flags & IDP_ONLYATTR)
1494 return 0;
1495 if (x->ex_flags & EXFLAG_CA) {
1496 if (crl->idp_flags & IDP_ONLYUSER)
1497 return 0;
1498 } else {
1499 if (crl->idp_flags & IDP_ONLYCA)
1500 return 0;
1501 }
1502 *preasons = crl->idp_reasons;
1503 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) {
1504 DIST_POINT *dp = sk_DIST_POINT_value(x->crldp, i);
1505 if (crldp_check_crlissuer(dp, crl, crl_score)) {
1506 if (!crl->idp || idp_check_dp(dp->distpoint, crl->idp->distpoint)) {
1507 *preasons &= dp->dp_reasons;
1508 return 1;
1509 }
1510 }
1511 }
1512 if ((!crl->idp || !crl->idp->distpoint)
1513 && (crl_score & CRL_SCORE_ISSUER_NAME))
1514 return 1;
1515 return 0;
1516 }
1517
1518 /*
1519 * Retrieve CRL corresponding to current certificate. If deltas enabled try
1520 * to find a delta CRL too
1521 */
1522
1523 static int get_crl_delta(X509_STORE_CTX *ctx,
1524 X509_CRL **pcrl, X509_CRL **pdcrl, X509 *x)
1525 {
1526 int ok;
1527 X509 *issuer = NULL;
1528 int crl_score = 0;
1529 unsigned int reasons;
1530 X509_CRL *crl = NULL, *dcrl = NULL;
1531 STACK_OF(X509_CRL) *skcrl;
1532 const X509_NAME *nm = X509_get_issuer_name(x);
1533
1534 reasons = ctx->current_reasons;
1535 ok = get_crl_sk(ctx, &crl, &dcrl,
1536 &issuer, &crl_score, &reasons, ctx->crls);
1537 if (ok)
1538 goto done;
1539
1540 /* Lookup CRLs from store */
1541
1542 skcrl = ctx->lookup_crls(ctx, nm);
1543
1544 /* If no CRLs found and a near match from get_crl_sk use that */
1545 if (!skcrl && crl)
1546 goto done;
1547
1548 get_crl_sk(ctx, &crl, &dcrl, &issuer, &crl_score, &reasons, skcrl);
1549
1550 sk_X509_CRL_pop_free(skcrl, X509_CRL_free);
1551
1552 done:
1553 /* If we got any kind of CRL use it and return success */
1554 if (crl) {
1555 ctx->current_issuer = issuer;
1556 ctx->current_crl_score = crl_score;
1557 ctx->current_reasons = reasons;
1558 *pcrl = crl;
1559 *pdcrl = dcrl;
1560 return 1;
1561 }
1562 return 0;
1563 }
1564
1565 /* Check CRL validity */
1566 static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
1567 {
1568 X509 *issuer = NULL;
1569 EVP_PKEY *ikey = NULL;
1570 int cnum = ctx->error_depth;
1571 int chnum = sk_X509_num(ctx->chain) - 1;
1572
1573 /* If we have an alternative CRL issuer cert use that */
1574 if (ctx->current_issuer)
1575 issuer = ctx->current_issuer;
1576 /*
1577 * Else find CRL issuer: if not last certificate then issuer is next
1578 * certificate in chain.
1579 */
1580 else if (cnum < chnum)
1581 issuer = sk_X509_value(ctx->chain, cnum + 1);
1582 else {
1583 issuer = sk_X509_value(ctx->chain, chnum);
1584 /* If not self-issued, can't check signature */
1585 if (!ctx->check_issued(ctx, issuer, issuer) &&
1586 !verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER))
1587 return 0;
1588 }
1589
1590 if (issuer == NULL)
1591 return 1;
1592
1593 /*
1594 * Skip most tests for deltas because they have already been done
1595 */
1596 if (!crl->base_crl_number) {
1597 /* Check for cRLSign bit if keyUsage present */
1598 if ((issuer->ex_flags & EXFLAG_KUSAGE) &&
1599 !(issuer->ex_kusage & KU_CRL_SIGN) &&
1600 !verify_cb_crl(ctx, X509_V_ERR_KEYUSAGE_NO_CRL_SIGN))
1601 return 0;
1602
1603 if (!(ctx->current_crl_score & CRL_SCORE_SCOPE) &&
1604 !verify_cb_crl(ctx, X509_V_ERR_DIFFERENT_CRL_SCOPE))
1605 return 0;
1606
1607 if (!(ctx->current_crl_score & CRL_SCORE_SAME_PATH) &&
1608 check_crl_path(ctx, ctx->current_issuer) <= 0 &&
1609 !verify_cb_crl(ctx, X509_V_ERR_CRL_PATH_VALIDATION_ERROR))
1610 return 0;
1611
1612 if ((crl->idp_flags & IDP_INVALID) &&
1613 !verify_cb_crl(ctx, X509_V_ERR_INVALID_EXTENSION))
1614 return 0;
1615 }
1616
1617 if (!(ctx->current_crl_score & CRL_SCORE_TIME) &&
1618 !check_crl_time(ctx, crl, 1))
1619 return 0;
1620
1621 /* Attempt to get issuer certificate public key */
1622 ikey = X509_get0_pubkey(issuer);
1623
1624 if (!ikey &&
1625 !verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY))
1626 return 0;
1627
1628 if (ikey) {
1629 int rv = X509_CRL_check_suiteb(crl, ikey, ctx->param->flags);
1630
1631 if (rv != X509_V_OK && !verify_cb_crl(ctx, rv))
1632 return 0;
1633 /* Verify CRL signature */
1634 if (X509_CRL_verify(crl, ikey) <= 0 &&
1635 !verify_cb_crl(ctx, X509_V_ERR_CRL_SIGNATURE_FAILURE))
1636 return 0;
1637 }
1638 return 1;
1639 }
1640
1641 /* Check certificate against CRL */
1642 static int cert_crl(X509_STORE_CTX *ctx, X509_CRL *crl, X509 *x)
1643 {
1644 X509_REVOKED *rev;
1645
1646 /*
1647 * The rules changed for this... previously if a CRL contained unhandled
1648 * critical extensions it could still be used to indicate a certificate
1649 * was revoked. This has since been changed since critical extensions can
1650 * change the meaning of CRL entries.
1651 */
1652 if (!(ctx->param->flags & X509_V_FLAG_IGNORE_CRITICAL)
1653 && (crl->flags & EXFLAG_CRITICAL) &&
1654 !verify_cb_crl(ctx, X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION))
1655 return 0;
1656 /*
1657 * Look for serial number of certificate in CRL. If found, make sure
1658 * reason is not removeFromCRL.
1659 */
1660 if (X509_CRL_get0_by_cert(crl, &rev, x)) {
1661 if (rev->reason == CRL_REASON_REMOVE_FROM_CRL)
1662 return 2;
1663 if (!verify_cb_crl(ctx, X509_V_ERR_CERT_REVOKED))
1664 return 0;
1665 }
1666
1667 return 1;
1668 }
1669
1670 static int check_policy(X509_STORE_CTX *ctx)
1671 {
1672 int ret;
1673
1674 if (ctx->parent)
1675 return 1;
1676 /*
1677 * With DANE, the trust anchor might be a bare public key, not a
1678 * certificate! In that case our chain does not have the trust anchor
1679 * certificate as a top-most element. This comports well with RFC5280
1680 * chain verification, since there too, the trust anchor is not part of the
1681 * chain to be verified. In particular, X509_policy_check() does not look
1682 * at the TA cert, but assumes that it is present as the top-most chain
1683 * element. We therefore temporarily push a NULL cert onto the chain if it
1684 * was verified via a bare public key, and pop it off right after the
1685 * X509_policy_check() call.
1686 */
1687 if (ctx->bare_ta_signed && !sk_X509_push(ctx->chain, NULL)) {
1688 X509err(X509_F_CHECK_POLICY, ERR_R_MALLOC_FAILURE);
1689 ctx->error = X509_V_ERR_OUT_OF_MEM;
1690 return 0;
1691 }
1692 ret = X509_policy_check(&ctx->tree, &ctx->explicit_policy, ctx->chain,
1693 ctx->param->policies, ctx->param->flags);
1694 if (ctx->bare_ta_signed)
1695 (void)sk_X509_pop(ctx->chain);
1696
1697 if (ret == X509_PCY_TREE_INTERNAL) {
1698 X509err(X509_F_CHECK_POLICY, ERR_R_MALLOC_FAILURE);
1699 ctx->error = X509_V_ERR_OUT_OF_MEM;
1700 return 0;
1701 }
1702 /* Invalid or inconsistent extensions */
1703 if (ret == X509_PCY_TREE_INVALID) {
1704 int i;
1705
1706 /* Locate certificates with bad extensions and notify callback. */
1707 for (i = 1; i < sk_X509_num(ctx->chain); i++) {
1708 X509 *x = sk_X509_value(ctx->chain, i);
1709
1710 if (!(x->ex_flags & EXFLAG_INVALID_POLICY))
1711 continue;
1712 if (!verify_cb_cert(ctx, x, i,
1713 X509_V_ERR_INVALID_POLICY_EXTENSION))
1714 return 0;
1715 }
1716 return 1;
1717 }
1718 if (ret == X509_PCY_TREE_FAILURE) {
1719 ctx->current_cert = NULL;
1720 ctx->error = X509_V_ERR_NO_EXPLICIT_POLICY;
1721 return ctx->verify_cb(0, ctx);
1722 }
1723 if (ret != X509_PCY_TREE_VALID) {
1724 X509err(X509_F_CHECK_POLICY, ERR_R_INTERNAL_ERROR);
1725 return 0;
1726 }
1727
1728 if (ctx->param->flags & X509_V_FLAG_NOTIFY_POLICY) {
1729 ctx->current_cert = NULL;
1730 /*
1731 * Verification errors need to be "sticky", a callback may have allowed
1732 * an SSL handshake to continue despite an error, and we must then
1733 * remain in an error state. Therefore, we MUST NOT clear earlier
1734 * verification errors by setting the error to X509_V_OK.
1735 */
1736 if (!ctx->verify_cb(2, ctx))
1737 return 0;
1738 }
1739
1740 return 1;
1741 }
1742
1743 /*-
1744 * Check certificate validity times.
1745 * If depth >= 0, invoke verification callbacks on error, otherwise just return
1746 * the validation status.
1747 *
1748 * Return 1 on success, 0 otherwise.
1749 */
1750 int x509_check_cert_time(X509_STORE_CTX *ctx, X509 *x, int depth)
1751 {
1752 time_t *ptime;
1753 int i;
1754
1755 if (ctx->param->flags & X509_V_FLAG_USE_CHECK_TIME)
1756 ptime = &ctx->param->check_time;
1757 else if (ctx->param->flags & X509_V_FLAG_NO_CHECK_TIME)
1758 return 1;
1759 else
1760 ptime = NULL;
1761
1762 i = X509_cmp_time(X509_get0_notBefore(x), ptime);
1763 if (i >= 0 && depth < 0)
1764 return 0;
1765 if (i == 0 && !verify_cb_cert(ctx, x, depth,
1766 X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD))
1767 return 0;
1768 if (i > 0 && !verify_cb_cert(ctx, x, depth, X509_V_ERR_CERT_NOT_YET_VALID))
1769 return 0;
1770
1771 i = X509_cmp_time(X509_get0_notAfter(x), ptime);
1772 if (i <= 0 && depth < 0)
1773 return 0;
1774 if (i == 0 && !verify_cb_cert(ctx, x, depth,
1775 X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD))
1776 return 0;
1777 if (i < 0 && !verify_cb_cert(ctx, x, depth, X509_V_ERR_CERT_HAS_EXPIRED))
1778 return 0;
1779 return 1;
1780 }
1781
1782 /* verify the issuer signatures and cert times of ctx->chain */
1783 static int internal_verify(X509_STORE_CTX *ctx)
1784 {
1785 int n = sk_X509_num(ctx->chain) - 1;
1786 X509 *xi = sk_X509_value(ctx->chain, n);
1787 X509 *xs;
1788
1789 /*
1790 * With DANE-verified bare public key TA signatures, it remains only to
1791 * check the timestamps of the top certificate. We report the issuer as
1792 * NULL, since all we have is a bare key.
1793 */
1794 if (ctx->bare_ta_signed) {
1795 xs = xi;
1796 xi = NULL;
1797 goto check_cert_time;
1798 }
1799
1800 if (ctx->check_issued(ctx, xi, xi))
1801 xs = xi; /* the typical case: last cert in the chain is self-issued */
1802 else {
1803 if (ctx->param->flags & X509_V_FLAG_PARTIAL_CHAIN) {
1804 xs = xi;
1805 goto check_cert_time;
1806 }
1807 if (n <= 0)
1808 return verify_cb_cert(ctx, xi, 0,
1809 X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE);
1810 n--;
1811 ctx->error_depth = n;
1812 xs = sk_X509_value(ctx->chain, n);
1813 }
1814
1815 /*
1816 * Do not clear ctx->error=0, it must be "sticky", only the user's callback
1817 * is allowed to reset errors (at its own peril).
1818 */
1819 while (n >= 0) {
1820 /*
1821 * For each iteration of this loop:
1822 * n is the subject depth
1823 * xs is the subject cert, for which the signature is to be checked
1824 * xi is the supposed issuer cert containing the public key to use
1825 * Initially xs == xi if the last cert in the chain is self-issued.
1826 *
1827 * Skip signature check for self-signed certificates unless explicitly
1828 * asked for because it does not add any security and just wastes time.
1829 */
1830 if (xs != xi || ((ctx->param->flags & X509_V_FLAG_CHECK_SS_SIGNATURE)
1831 && (xi->ex_flags & EXFLAG_SS) != 0)) {
1832 EVP_PKEY *pkey;
1833 /*
1834 * If the issuer's public key is not available or its key usage
1835 * does not support issuing the subject cert, report the issuer
1836 * cert and its depth (rather than n, the depth of the subject).
1837 */
1838 int issuer_depth = n + (xs == xi ? 0 : 1);
1839 /*
1840 * According to https://tools.ietf.org/html/rfc5280#section-6.1.4
1841 * step (n) we must check any given key usage extension in a CA cert
1842 * when preparing the verification of a certificate issued by it.
1843 * According to https://tools.ietf.org/html/rfc5280#section-4.2.1.3
1844 * we must not verify a certifiate signature if the key usage of the
1845 * CA certificate that issued the certificate prohibits signing.
1846 * In case the 'issuing' certificate is the last in the chain and is
1847 * not a CA certificate but a 'self-issued' end-entity cert (i.e.,
1848 * xs == xi && !(xi->ex_flags & EXFLAG_CA)) RFC 5280 does not apply
1849 * (see https://tools.ietf.org/html/rfc6818#section-2) and thus
1850 * we are free to ignore any key usage restrictions on such certs.
1851 */
1852 int ret = xs == xi && (xi->ex_flags & EXFLAG_CA) == 0
1853 ? X509_V_OK : x509_signing_allowed(xi, xs);
1854
1855 if (ret != X509_V_OK && !verify_cb_cert(ctx, xi, issuer_depth, ret))
1856 return 0;
1857 if ((pkey = X509_get0_pubkey(xi)) == NULL) {
1858 ret = X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY;
1859 if (!verify_cb_cert(ctx, xi, issuer_depth, ret))
1860 return 0;
1861 } else if (X509_verify(xs, pkey) <= 0) {
1862 ret = X509_V_ERR_CERT_SIGNATURE_FAILURE;
1863 if (!verify_cb_cert(ctx, xs, n, ret))
1864 return 0;
1865 }
1866 }
1867
1868 check_cert_time:
1869 /* Calls verify callback as needed */
1870 if (!x509_check_cert_time(ctx, xs, n))
1871 return 0;
1872
1873 /*
1874 * Signal success at this depth. However, the previous error (if any)
1875 * is retained.
1876 */
1877 ctx->current_issuer = xi;
1878 ctx->current_cert = xs;
1879 ctx->error_depth = n;
1880 if (!ctx->verify_cb(1, ctx))
1881 return 0;
1882
1883 if (--n >= 0) {
1884 xi = xs;
1885 xs = sk_X509_value(ctx->chain, n);
1886 }
1887 }
1888 return 1;
1889 }
1890
1891 int X509_cmp_current_time(const ASN1_TIME *ctm)
1892 {
1893 return X509_cmp_time(ctm, NULL);
1894 }
1895
1896 int X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time)
1897 {
1898 static const size_t utctime_length = sizeof("YYMMDDHHMMSSZ") - 1;
1899 static const size_t generalizedtime_length = sizeof("YYYYMMDDHHMMSSZ") - 1;
1900 ASN1_TIME *asn1_cmp_time = NULL;
1901 int i, day, sec, ret = 0;
1902 #ifdef CHARSET_EBCDIC
1903 const char upper_z = 0x5A;
1904 #else
1905 const char upper_z = 'Z';
1906 #endif
1907 /*
1908 * Note that ASN.1 allows much more slack in the time format than RFC5280.
1909 * In RFC5280, the representation is fixed:
1910 * UTCTime: YYMMDDHHMMSSZ
1911 * GeneralizedTime: YYYYMMDDHHMMSSZ
1912 *
1913 * We do NOT currently enforce the following RFC 5280 requirement:
1914 * "CAs conforming to this profile MUST always encode certificate
1915 * validity dates through the year 2049 as UTCTime; certificate validity
1916 * dates in 2050 or later MUST be encoded as GeneralizedTime."
1917 */
1918 switch (ctm->type) {
1919 case V_ASN1_UTCTIME:
1920 if (ctm->length != (int)(utctime_length))
1921 return 0;
1922 break;
1923 case V_ASN1_GENERALIZEDTIME:
1924 if (ctm->length != (int)(generalizedtime_length))
1925 return 0;
1926 break;
1927 default:
1928 return 0;
1929 }
1930
1931 /**
1932 * Verify the format: the ASN.1 functions we use below allow a more
1933 * flexible format than what's mandated by RFC 5280.
1934 * Digit and date ranges will be verified in the conversion methods.
1935 */
1936 for (i = 0; i < ctm->length - 1; i++) {
1937 if (!ascii_isdigit(ctm->data[i]))
1938 return 0;
1939 }
1940 if (ctm->data[ctm->length - 1] != upper_z)
1941 return 0;
1942
1943 /*
1944 * There is ASN1_UTCTIME_cmp_time_t but no
1945 * ASN1_GENERALIZEDTIME_cmp_time_t or ASN1_TIME_cmp_time_t,
1946 * so we go through ASN.1
1947 */
1948 asn1_cmp_time = X509_time_adj(NULL, 0, cmp_time);
1949 if (asn1_cmp_time == NULL)
1950 goto err;
1951 if (!ASN1_TIME_diff(&day, &sec, ctm, asn1_cmp_time))
1952 goto err;
1953
1954 /*
1955 * X509_cmp_time comparison is <=.
1956 * The return value 0 is reserved for errors.
1957 */
1958 ret = (day >= 0 && sec >= 0) ? -1 : 1;
1959
1960 err:
1961 ASN1_TIME_free(asn1_cmp_time);
1962 return ret;
1963 }
1964
1965 /*
1966 * Return 0 if time should not be checked or reference time is in range,
1967 * or else 1 if it is past the end, or -1 if it is before the start
1968 */
1969 int X509_cmp_timeframe(const X509_VERIFY_PARAM *vpm,
1970 const ASN1_TIME *start, const ASN1_TIME *end)
1971 {
1972 time_t ref_time;
1973 time_t *time = NULL;
1974 unsigned long flags = vpm == NULL ? 0 : X509_VERIFY_PARAM_get_flags(vpm);
1975
1976 if ((flags & X509_V_FLAG_USE_CHECK_TIME) != 0) {
1977 ref_time = X509_VERIFY_PARAM_get_time(vpm);
1978 time = &ref_time;
1979 } else if ((flags & X509_V_FLAG_NO_CHECK_TIME) != 0) {
1980 return 0; /* this means ok */
1981 } /* else reference time is the current time */
1982
1983 if (end != NULL && X509_cmp_time(end, time) < 0)
1984 return 1;
1985 if (start != NULL && X509_cmp_time(start, time) > 0)
1986 return -1;
1987 return 0;
1988 }
1989
1990 ASN1_TIME *X509_gmtime_adj(ASN1_TIME *s, long adj)
1991 {
1992 return X509_time_adj(s, adj, NULL);
1993 }
1994
1995 ASN1_TIME *X509_time_adj(ASN1_TIME *s, long offset_sec, time_t *in_tm)
1996 {
1997 return X509_time_adj_ex(s, 0, offset_sec, in_tm);
1998 }
1999
2000 ASN1_TIME *X509_time_adj_ex(ASN1_TIME *s,
2001 int offset_day, long offset_sec, time_t *in_tm)
2002 {
2003 time_t t;
2004
2005 if (in_tm)
2006 t = *in_tm;
2007 else
2008 time(&t);
2009
2010 if (s && !(s->flags & ASN1_STRING_FLAG_MSTRING)) {
2011 if (s->type == V_ASN1_UTCTIME)
2012 return ASN1_UTCTIME_adj(s, t, offset_day, offset_sec);
2013 if (s->type == V_ASN1_GENERALIZEDTIME)
2014 return ASN1_GENERALIZEDTIME_adj(s, t, offset_day, offset_sec);
2015 }
2016 return ASN1_TIME_adj(s, t, offset_day, offset_sec);
2017 }
2018
2019 int X509_get_pubkey_parameters(EVP_PKEY *pkey, STACK_OF(X509) *chain)
2020 {
2021 EVP_PKEY *ktmp = NULL, *ktmp2;
2022 int i, j;
2023
2024 if ((pkey != NULL) && !EVP_PKEY_missing_parameters(pkey))
2025 return 1;
2026
2027 for (i = 0; i < sk_X509_num(chain); i++) {
2028 ktmp = X509_get0_pubkey(sk_X509_value(chain, i));
2029 if (ktmp == NULL) {
2030 X509err(X509_F_X509_GET_PUBKEY_PARAMETERS,
2031 X509_R_UNABLE_TO_GET_CERTS_PUBLIC_KEY);
2032 return 0;
2033 }
2034 if (!EVP_PKEY_missing_parameters(ktmp))
2035 break;
2036 }
2037 if (ktmp == NULL) {
2038 X509err(X509_F_X509_GET_PUBKEY_PARAMETERS,
2039 X509_R_UNABLE_TO_FIND_PARAMETERS_IN_CHAIN);
2040 return 0;
2041 }
2042
2043 /* first, populate the other certs */
2044 for (j = i - 1; j >= 0; j--) {
2045 ktmp2 = X509_get0_pubkey(sk_X509_value(chain, j));
2046 EVP_PKEY_copy_parameters(ktmp2, ktmp);
2047 }
2048
2049 if (pkey != NULL)
2050 EVP_PKEY_copy_parameters(pkey, ktmp);
2051 return 1;
2052 }
2053
2054 /* Make a delta CRL as the diff between two full CRLs */
2055
2056 X509_CRL *X509_CRL_diff(X509_CRL *base, X509_CRL *newer,
2057 EVP_PKEY *skey, const EVP_MD *md, unsigned int flags)
2058 {
2059 X509_CRL *crl = NULL;
2060 int i;
2061 STACK_OF(X509_REVOKED) *revs = NULL;
2062 /* CRLs can't be delta already */
2063 if (base->base_crl_number || newer->base_crl_number) {
2064 X509err(X509_F_X509_CRL_DIFF, X509_R_CRL_ALREADY_DELTA);
2065 return NULL;
2066 }
2067 /* Base and new CRL must have a CRL number */
2068 if (!base->crl_number || !newer->crl_number) {
2069 X509err(X509_F_X509_CRL_DIFF, X509_R_NO_CRL_NUMBER);
2070 return NULL;
2071 }
2072 /* Issuer names must match */
2073 if (X509_NAME_cmp(X509_CRL_get_issuer(base), X509_CRL_get_issuer(newer))) {
2074 X509err(X509_F_X509_CRL_DIFF, X509_R_ISSUER_MISMATCH);
2075 return NULL;
2076 }
2077 /* AKID and IDP must match */
2078 if (!crl_extension_match(base, newer, NID_authority_key_identifier)) {
2079 X509err(X509_F_X509_CRL_DIFF, X509_R_AKID_MISMATCH);
2080 return NULL;
2081 }
2082 if (!crl_extension_match(base, newer, NID_issuing_distribution_point)) {
2083 X509err(X509_F_X509_CRL_DIFF, X509_R_IDP_MISMATCH);
2084 return NULL;
2085 }
2086 /* Newer CRL number must exceed full CRL number */
2087 if (ASN1_INTEGER_cmp(newer->crl_number, base->crl_number) <= 0) {
2088 X509err(X509_F_X509_CRL_DIFF, X509_R_NEWER_CRL_NOT_NEWER);
2089 return NULL;
2090 }
2091 /* CRLs must verify */
2092 if (skey && (X509_CRL_verify(base, skey) <= 0 ||
2093 X509_CRL_verify(newer, skey) <= 0)) {
2094 X509err(X509_F_X509_CRL_DIFF, X509_R_CRL_VERIFY_FAILURE);
2095 return NULL;
2096 }
2097 /* Create new CRL */
2098 crl = X509_CRL_new();
2099 if (crl == NULL || !X509_CRL_set_version(crl, 1))
2100 goto memerr;
2101 /* Set issuer name */
2102 if (!X509_CRL_set_issuer_name(crl, X509_CRL_get_issuer(newer)))
2103 goto memerr;
2104
2105 if (!X509_CRL_set1_lastUpdate(crl, X509_CRL_get0_lastUpdate(newer)))
2106 goto memerr;
2107 if (!X509_CRL_set1_nextUpdate(crl, X509_CRL_get0_nextUpdate(newer)))
2108 goto memerr;
2109
2110 /* Set base CRL number: must be critical */
2111
2112 if (!X509_CRL_add1_ext_i2d(crl, NID_delta_crl, base->crl_number, 1, 0))
2113 goto memerr;
2114
2115 /*
2116 * Copy extensions across from newest CRL to delta: this will set CRL
2117 * number to correct value too.
2118 */
2119
2120 for (i = 0; i < X509_CRL_get_ext_count(newer); i++) {
2121 X509_EXTENSION *ext;
2122 ext = X509_CRL_get_ext(newer, i);
2123 if (!X509_CRL_add_ext(crl, ext, -1))
2124 goto memerr;
2125 }
2126
2127 /* Go through revoked entries, copying as needed */
2128
2129 revs = X509_CRL_get_REVOKED(newer);
2130
2131 for (i = 0; i < sk_X509_REVOKED_num(revs); i++) {
2132 X509_REVOKED *rvn, *rvtmp;
2133 rvn = sk_X509_REVOKED_value(revs, i);
2134 /*
2135 * Add only if not also in base. TODO: need something cleverer here
2136 * for some more complex CRLs covering multiple CAs.
2137 */
2138 if (!X509_CRL_get0_by_serial(base, &rvtmp, &rvn->serialNumber)) {
2139 rvtmp = X509_REVOKED_dup(rvn);
2140 if (!rvtmp)
2141 goto memerr;
2142 if (!X509_CRL_add0_revoked(crl, rvtmp)) {
2143 X509_REVOKED_free(rvtmp);
2144 goto memerr;
2145 }
2146 }
2147 }
2148 /* TODO: optionally prune deleted entries */
2149
2150 if (skey && md && !X509_CRL_sign(crl, skey, md))
2151 goto memerr;
2152
2153 return crl;
2154
2155 memerr:
2156 X509err(X509_F_X509_CRL_DIFF, ERR_R_MALLOC_FAILURE);
2157 X509_CRL_free(crl);
2158 return NULL;
2159 }
2160
2161 int X509_STORE_CTX_set_ex_data(X509_STORE_CTX *ctx, int idx, void *data)
2162 {
2163 return CRYPTO_set_ex_data(&ctx->ex_data, idx, data);
2164 }
2165
2166 void *X509_STORE_CTX_get_ex_data(const X509_STORE_CTX *ctx, int idx)
2167 {
2168 return CRYPTO_get_ex_data(&ctx->ex_data, idx);
2169 }
2170
2171 int X509_STORE_CTX_get_error(const X509_STORE_CTX *ctx)
2172 {
2173 return ctx->error;
2174 }
2175
2176 void X509_STORE_CTX_set_error(X509_STORE_CTX *ctx, int err)
2177 {
2178 ctx->error = err;
2179 }
2180
2181 int X509_STORE_CTX_get_error_depth(const X509_STORE_CTX *ctx)
2182 {
2183 return ctx->error_depth;
2184 }
2185
2186 void X509_STORE_CTX_set_error_depth(X509_STORE_CTX *ctx, int depth)
2187 {
2188 ctx->error_depth = depth;
2189 }
2190
2191 X509 *X509_STORE_CTX_get_current_cert(const X509_STORE_CTX *ctx)
2192 {
2193 return ctx->current_cert;
2194 }
2195
2196 void X509_STORE_CTX_set_current_cert(X509_STORE_CTX *ctx, X509 *x)
2197 {
2198 ctx->current_cert = x;
2199 }
2200
2201 STACK_OF(X509) *X509_STORE_CTX_get0_chain(const X509_STORE_CTX *ctx)
2202 {
2203 return ctx->chain;
2204 }
2205
2206 STACK_OF(X509) *X509_STORE_CTX_get1_chain(const X509_STORE_CTX *ctx)
2207 {
2208 if (!ctx->chain)
2209 return NULL;
2210 return X509_chain_up_ref(ctx->chain);
2211 }
2212
2213 X509 *X509_STORE_CTX_get0_current_issuer(const X509_STORE_CTX *ctx)
2214 {
2215 return ctx->current_issuer;
2216 }
2217
2218 X509_CRL *X509_STORE_CTX_get0_current_crl(const X509_STORE_CTX *ctx)
2219 {
2220 return ctx->current_crl;
2221 }
2222
2223 X509_STORE_CTX *X509_STORE_CTX_get0_parent_ctx(const X509_STORE_CTX *ctx)
2224 {
2225 return ctx->parent;
2226 }
2227
2228 void X509_STORE_CTX_set_cert(X509_STORE_CTX *ctx, X509 *x)
2229 {
2230 ctx->cert = x;
2231 }
2232
2233 void X509_STORE_CTX_set0_crls(X509_STORE_CTX *ctx, STACK_OF(X509_CRL) *sk)
2234 {
2235 ctx->crls = sk;
2236 }
2237
2238 int X509_STORE_CTX_set_purpose(X509_STORE_CTX *ctx, int purpose)
2239 {
2240 /*
2241 * XXX: Why isn't this function always used to set the associated trust?
2242 * Should there even be a VPM->trust field at all? Or should the trust
2243 * always be inferred from the purpose by X509_STORE_CTX_init().
2244 */
2245 return X509_STORE_CTX_purpose_inherit(ctx, 0, purpose, 0);
2246 }
2247
2248 int X509_STORE_CTX_set_trust(X509_STORE_CTX *ctx, int trust)
2249 {
2250 /*
2251 * XXX: See above, this function would only be needed when the default
2252 * trust for the purpose needs an override in a corner case.
2253 */
2254 return X509_STORE_CTX_purpose_inherit(ctx, 0, 0, trust);
2255 }
2256
2257 /*
2258 * This function is used to set the X509_STORE_CTX purpose and trust values.
2259 * This is intended to be used when another structure has its own trust and
2260 * purpose values which (if set) will be inherited by the ctx. If they aren't
2261 * set then we will usually have a default purpose in mind which should then
2262 * be used to set the trust value. An example of this is SSL use: an SSL
2263 * structure will have its own purpose and trust settings which the
2264 * application can set: if they aren't set then we use the default of SSL
2265 * client/server.
2266 */
2267
2268 int X509_STORE_CTX_purpose_inherit(X509_STORE_CTX *ctx, int def_purpose,
2269 int purpose, int trust)
2270 {
2271 int idx;
2272 /* If purpose not set use default */
2273 if (purpose == 0)
2274 purpose = def_purpose;
2275 /* If we have a purpose then check it is valid */
2276 if (purpose != 0) {
2277 X509_PURPOSE *ptmp;
2278 idx = X509_PURPOSE_get_by_id(purpose);
2279 if (idx == -1) {
2280 X509err(X509_F_X509_STORE_CTX_PURPOSE_INHERIT,
2281 X509_R_UNKNOWN_PURPOSE_ID);
2282 return 0;
2283 }
2284 ptmp = X509_PURPOSE_get0(idx);
2285 if (ptmp->trust == X509_TRUST_DEFAULT) {
2286 idx = X509_PURPOSE_get_by_id(def_purpose);
2287 /*
2288 * XXX: In the two callers above def_purpose is always 0, which is
2289 * not a known value, so idx will always be -1. How is the
2290 * X509_TRUST_DEFAULT case actually supposed to be handled?
2291 */
2292 if (idx == -1) {
2293 X509err(X509_F_X509_STORE_CTX_PURPOSE_INHERIT,
2294 X509_R_UNKNOWN_PURPOSE_ID);
2295 return 0;
2296 }
2297 ptmp = X509_PURPOSE_get0(idx);
2298 }
2299 /* If trust not set then get from purpose default */
2300 if (!trust)
2301 trust = ptmp->trust;
2302 }
2303 if (trust) {
2304 idx = X509_TRUST_get_by_id(trust);
2305 if (idx == -1) {
2306 X509err(X509_F_X509_STORE_CTX_PURPOSE_INHERIT,
2307 X509_R_UNKNOWN_TRUST_ID);
2308 return 0;
2309 }
2310 }
2311
2312 if (purpose && !ctx->param->purpose)
2313 ctx->param->purpose = purpose;
2314 if (trust && !ctx->param->trust)
2315 ctx->param->trust = trust;
2316 return 1;
2317 }
2318
2319 X509_STORE_CTX *X509_STORE_CTX_new_with_libctx(OPENSSL_CTX *libctx,
2320 const char *propq)
2321 {
2322 X509_STORE_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
2323
2324 if (ctx == NULL) {
2325 X509err(0, ERR_R_MALLOC_FAILURE);
2326 return NULL;
2327 }
2328
2329 ctx->libctx = libctx;
2330 if (propq != NULL) {
2331 ctx->propq = OPENSSL_strdup(propq);
2332 if (ctx->propq == NULL) {
2333 OPENSSL_free(ctx);
2334 X509err(0, ERR_R_MALLOC_FAILURE);
2335 return NULL;
2336 }
2337 }
2338
2339 return ctx;
2340 }
2341
2342 X509_STORE_CTX *X509_STORE_CTX_new(void)
2343 {
2344 return X509_STORE_CTX_new_with_libctx(NULL, NULL);
2345 }
2346
2347
2348 void X509_STORE_CTX_free(X509_STORE_CTX *ctx)
2349 {
2350 if (ctx == NULL)
2351 return;
2352
2353 X509_STORE_CTX_cleanup(ctx);
2354
2355 /* libctx and propq survive X509_STORE_CTX_cleanup() */
2356 OPENSSL_free(ctx->propq);
2357
2358 OPENSSL_free(ctx);
2359 }
2360
2361 int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
2362 STACK_OF(X509) *chain)
2363 {
2364 int ret = 1;
2365
2366 ctx->store = store;
2367 ctx->cert = x509;
2368 ctx->untrusted = chain;
2369 ctx->crls = NULL;
2370 ctx->num_untrusted = 0;
2371 ctx->other_ctx = NULL;
2372 ctx->valid = 0;
2373 ctx->chain = NULL;
2374 ctx->error = 0;
2375 ctx->explicit_policy = 0;
2376 ctx->error_depth = 0;
2377 ctx->current_cert = NULL;
2378 ctx->current_issuer = NULL;
2379 ctx->current_crl = NULL;
2380 ctx->current_crl_score = 0;
2381 ctx->current_reasons = 0;
2382 ctx->tree = NULL;
2383 ctx->parent = NULL;
2384 ctx->dane = NULL;
2385 ctx->bare_ta_signed = 0;
2386 /* Zero ex_data to make sure we're cleanup-safe */
2387 memset(&ctx->ex_data, 0, sizeof(ctx->ex_data));
2388
2389 /* store->cleanup is always 0 in OpenSSL, if set must be idempotent */
2390 if (store)
2391 ctx->cleanup = store->cleanup;
2392 else
2393 ctx->cleanup = 0;
2394
2395 if (store && store->check_issued)
2396 ctx->check_issued = store->check_issued;
2397 else
2398 ctx->check_issued = check_issued;
2399
2400 if (store && store->get_issuer)
2401 ctx->get_issuer = store->get_issuer;
2402 else
2403 ctx->get_issuer = X509_STORE_CTX_get1_issuer;
2404
2405 if (store && store->verify_cb)
2406 ctx->verify_cb = store->verify_cb;
2407 else
2408 ctx->verify_cb = null_callback;
2409
2410 if (store && store->verify)
2411 ctx->verify = store->verify;
2412 else
2413 ctx->verify = internal_verify;
2414
2415 if (store && store->check_revocation)
2416 ctx->check_revocation = store->check_revocation;
2417 else
2418 ctx->check_revocation = check_revocation;
2419
2420 if (store && store->get_crl)
2421 ctx->get_crl = store->get_crl;
2422 else
2423 ctx->get_crl = NULL;
2424
2425 if (store && store->check_crl)
2426 ctx->check_crl = store->check_crl;
2427 else
2428 ctx->check_crl = check_crl;
2429
2430 if (store && store->cert_crl)
2431 ctx->cert_crl = store->cert_crl;
2432 else
2433 ctx->cert_crl = cert_crl;
2434
2435 if (store && store->check_policy)
2436 ctx->check_policy = store->check_policy;
2437 else
2438 ctx->check_policy = check_policy;
2439
2440 if (store && store->lookup_certs)
2441 ctx->lookup_certs = store->lookup_certs;
2442 else
2443 ctx->lookup_certs = X509_STORE_CTX_get1_certs;
2444
2445 if (store && store->lookup_crls)
2446 ctx->lookup_crls = store->lookup_crls;
2447 else
2448 ctx->lookup_crls = X509_STORE_CTX_get1_crls;
2449
2450 ctx->param = X509_VERIFY_PARAM_new();
2451 if (ctx->param == NULL) {
2452 X509err(X509_F_X509_STORE_CTX_INIT, ERR_R_MALLOC_FAILURE);
2453 goto err;
2454 }
2455
2456 /*
2457 * Inherit callbacks and flags from X509_STORE if not set use defaults.
2458 */
2459 if (store)
2460 ret = X509_VERIFY_PARAM_inherit(ctx->param, store->param);
2461 else
2462 ctx->param->inh_flags |= X509_VP_FLAG_DEFAULT | X509_VP_FLAG_ONCE;
2463
2464 if (ret)
2465 ret = X509_VERIFY_PARAM_inherit(ctx->param,
2466 X509_VERIFY_PARAM_lookup("default"));
2467
2468 if (ret == 0) {
2469 X509err(X509_F_X509_STORE_CTX_INIT, ERR_R_MALLOC_FAILURE);
2470 goto err;
2471 }
2472
2473 /*
2474 * XXX: For now, continue to inherit trust from VPM, but infer from the
2475 * purpose if this still yields the default value.
2476 */
2477 if (ctx->param->trust == X509_TRUST_DEFAULT) {
2478 int idx = X509_PURPOSE_get_by_id(ctx->param->purpose);
2479 X509_PURPOSE *xp = X509_PURPOSE_get0(idx);
2480
2481 if (xp != NULL)
2482 ctx->param->trust = X509_PURPOSE_get_trust(xp);
2483 }
2484
2485 if (CRYPTO_new_ex_data(CRYPTO_EX_INDEX_X509_STORE_CTX, ctx,
2486 &ctx->ex_data))
2487 return 1;
2488 X509err(X509_F_X509_STORE_CTX_INIT, ERR_R_MALLOC_FAILURE);
2489
2490 err:
2491 /*
2492 * On error clean up allocated storage, if the store context was not
2493 * allocated with X509_STORE_CTX_new() this is our last chance to do so.
2494 */
2495 X509_STORE_CTX_cleanup(ctx);
2496 return 0;
2497 }
2498
2499 /*
2500 * Set alternative lookup method: just a STACK of trusted certificates. This
2501 * avoids X509_STORE nastiness where it isn't needed.
2502 */
2503 void X509_STORE_CTX_set0_trusted_stack(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
2504 {
2505 ctx->other_ctx = sk;
2506 ctx->get_issuer = get_issuer_sk;
2507 ctx->lookup_certs = lookup_certs_sk;
2508 }
2509
2510 void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx)
2511 {
2512 /*
2513 * We need to be idempotent because, unfortunately, free() also calls
2514 * cleanup(), so the natural call sequence new(), init(), cleanup(), free()
2515 * calls cleanup() for the same object twice! Thus we must zero the
2516 * pointers below after they're freed!
2517 */
2518 /* Seems to always be 0 in OpenSSL, do this at most once. */
2519 if (ctx->cleanup != NULL) {
2520 ctx->cleanup(ctx);
2521 ctx->cleanup = NULL;
2522 }
2523 if (ctx->param != NULL) {
2524 if (ctx->parent == NULL)
2525 X509_VERIFY_PARAM_free(ctx->param);
2526 ctx->param = NULL;
2527 }
2528 X509_policy_tree_free(ctx->tree);
2529 ctx->tree = NULL;
2530 sk_X509_pop_free(ctx->chain, X509_free);
2531 ctx->chain = NULL;
2532 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_X509_STORE_CTX, ctx, &(ctx->ex_data));
2533 memset(&ctx->ex_data, 0, sizeof(ctx->ex_data));
2534 }
2535
2536 void X509_STORE_CTX_set_depth(X509_STORE_CTX *ctx, int depth)
2537 {
2538 X509_VERIFY_PARAM_set_depth(ctx->param, depth);
2539 }
2540
2541 void X509_STORE_CTX_set_flags(X509_STORE_CTX *ctx, unsigned long flags)
2542 {
2543 X509_VERIFY_PARAM_set_flags(ctx->param, flags);
2544 }
2545
2546 void X509_STORE_CTX_set_time(X509_STORE_CTX *ctx, unsigned long flags,
2547 time_t t)
2548 {
2549 X509_VERIFY_PARAM_set_time(ctx->param, t);
2550 }
2551
2552 X509 *X509_STORE_CTX_get0_cert(const X509_STORE_CTX *ctx)
2553 {
2554 return ctx->cert;
2555 }
2556
2557 STACK_OF(X509) *X509_STORE_CTX_get0_untrusted(const X509_STORE_CTX *ctx)
2558 {
2559 return ctx->untrusted;
2560 }
2561
2562 void X509_STORE_CTX_set0_untrusted(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
2563 {
2564 ctx->untrusted = sk;
2565 }
2566
2567 void X509_STORE_CTX_set0_verified_chain(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
2568 {
2569 sk_X509_pop_free(ctx->chain, X509_free);
2570 ctx->chain = sk;
2571 }
2572
2573 void X509_STORE_CTX_set_verify_cb(X509_STORE_CTX *ctx,
2574 X509_STORE_CTX_verify_cb verify_cb)
2575 {
2576 ctx->verify_cb = verify_cb;
2577 }
2578
2579 X509_STORE_CTX_verify_cb X509_STORE_CTX_get_verify_cb(const X509_STORE_CTX *ctx)
2580 {
2581 return ctx->verify_cb;
2582 }
2583
2584 void X509_STORE_CTX_set_verify(X509_STORE_CTX *ctx,
2585 X509_STORE_CTX_verify_fn verify)
2586 {
2587 ctx->verify = verify;
2588 }
2589
2590 X509_STORE_CTX_verify_fn X509_STORE_CTX_get_verify(const X509_STORE_CTX *ctx)
2591 {
2592 return ctx->verify;
2593 }
2594
2595 X509_STORE_CTX_get_issuer_fn X509_STORE_CTX_get_get_issuer(const X509_STORE_CTX *ctx)
2596 {
2597 return ctx->get_issuer;
2598 }
2599
2600 X509_STORE_CTX_check_issued_fn
2601 X509_STORE_CTX_get_check_issued(const X509_STORE_CTX *ctx)
2602 {
2603 return ctx->check_issued;
2604 }
2605
2606 X509_STORE_CTX_check_revocation_fn
2607 X509_STORE_CTX_get_check_revocation(const X509_STORE_CTX *ctx)
2608 {
2609 return ctx->check_revocation;
2610 }
2611
2612 X509_STORE_CTX_get_crl_fn X509_STORE_CTX_get_get_crl(const X509_STORE_CTX *ctx)
2613 {
2614 return ctx->get_crl;
2615 }
2616
2617 X509_STORE_CTX_check_crl_fn X509_STORE_CTX_get_check_crl(const X509_STORE_CTX *ctx)
2618 {
2619 return ctx->check_crl;
2620 }
2621
2622 X509_STORE_CTX_cert_crl_fn X509_STORE_CTX_get_cert_crl(const X509_STORE_CTX *ctx)
2623 {
2624 return ctx->cert_crl;
2625 }
2626
2627 X509_STORE_CTX_check_policy_fn
2628 X509_STORE_CTX_get_check_policy(const X509_STORE_CTX *ctx)
2629 {
2630 return ctx->check_policy;
2631 }
2632
2633 X509_STORE_CTX_lookup_certs_fn
2634 X509_STORE_CTX_get_lookup_certs(const X509_STORE_CTX *ctx)
2635 {
2636 return ctx->lookup_certs;
2637 }
2638
2639 X509_STORE_CTX_lookup_crls_fn
2640 X509_STORE_CTX_get_lookup_crls(const X509_STORE_CTX *ctx)
2641 {
2642 return ctx->lookup_crls;
2643 }
2644
2645 X509_STORE_CTX_cleanup_fn X509_STORE_CTX_get_cleanup(const X509_STORE_CTX *ctx)
2646 {
2647 return ctx->cleanup;
2648 }
2649
2650 X509_POLICY_TREE *X509_STORE_CTX_get0_policy_tree(const X509_STORE_CTX *ctx)
2651 {
2652 return ctx->tree;
2653 }
2654
2655 int X509_STORE_CTX_get_explicit_policy(const X509_STORE_CTX *ctx)
2656 {
2657 return ctx->explicit_policy;
2658 }
2659
2660 int X509_STORE_CTX_get_num_untrusted(const X509_STORE_CTX *ctx)
2661 {
2662 return ctx->num_untrusted;
2663 }
2664
2665 int X509_STORE_CTX_set_default(X509_STORE_CTX *ctx, const char *name)
2666 {
2667 const X509_VERIFY_PARAM *param;
2668
2669 param = X509_VERIFY_PARAM_lookup(name);
2670 if (param == NULL)
2671 return 0;
2672 return X509_VERIFY_PARAM_inherit(ctx->param, param);
2673 }
2674
2675 X509_VERIFY_PARAM *X509_STORE_CTX_get0_param(const X509_STORE_CTX *ctx)
2676 {
2677 return ctx->param;
2678 }
2679
2680 void X509_STORE_CTX_set0_param(X509_STORE_CTX *ctx, X509_VERIFY_PARAM *param)
2681 {
2682 X509_VERIFY_PARAM_free(ctx->param);
2683 ctx->param = param;
2684 }
2685
2686 void X509_STORE_CTX_set0_dane(X509_STORE_CTX *ctx, SSL_DANE *dane)
2687 {
2688 ctx->dane = dane;
2689 }
2690
2691 static unsigned char *dane_i2d(
2692 X509 *cert,
2693 uint8_t selector,
2694 unsigned int *i2dlen)
2695 {
2696 unsigned char *buf = NULL;
2697 int len;
2698
2699 /*
2700 * Extract ASN.1 DER form of certificate or public key.
2701 */
2702 switch (selector) {
2703 case DANETLS_SELECTOR_CERT:
2704 len = i2d_X509(cert, &buf);
2705 break;
2706 case DANETLS_SELECTOR_SPKI:
2707 len = i2d_X509_PUBKEY(X509_get_X509_PUBKEY(cert), &buf);
2708 break;
2709 default:
2710 X509err(X509_F_DANE_I2D, X509_R_BAD_SELECTOR);
2711 return NULL;
2712 }
2713
2714 if (len < 0 || buf == NULL) {
2715 X509err(X509_F_DANE_I2D, ERR_R_MALLOC_FAILURE);
2716 return NULL;
2717 }
2718
2719 *i2dlen = (unsigned int)len;
2720 return buf;
2721 }
2722
2723 #define DANETLS_NONE 256 /* impossible uint8_t */
2724
2725 static int dane_match(X509_STORE_CTX *ctx, X509 *cert, int depth)
2726 {
2727 SSL_DANE *dane = ctx->dane;
2728 unsigned usage = DANETLS_NONE;
2729 unsigned selector = DANETLS_NONE;
2730 unsigned ordinal = DANETLS_NONE;
2731 unsigned mtype = DANETLS_NONE;
2732 unsigned char *i2dbuf = NULL;
2733 unsigned int i2dlen = 0;
2734 unsigned char mdbuf[EVP_MAX_MD_SIZE];
2735 unsigned char *cmpbuf = NULL;
2736 unsigned int cmplen = 0;
2737 int i;
2738 int recnum;
2739 int matched = 0;
2740 danetls_record *t = NULL;
2741 uint32_t mask;
2742
2743 mask = (depth == 0) ? DANETLS_EE_MASK : DANETLS_TA_MASK;
2744
2745 /*
2746 * The trust store is not applicable with DANE-TA(2)
2747 */
2748 if (depth >= ctx->num_untrusted)
2749 mask &= DANETLS_PKIX_MASK;
2750
2751 /*
2752 * If we've previously matched a PKIX-?? record, no need to test any
2753 * further PKIX-?? records, it remains to just build the PKIX chain.
2754 * Had the match been a DANE-?? record, we'd be done already.
2755 */
2756 if (dane->mdpth >= 0)
2757 mask &= ~DANETLS_PKIX_MASK;
2758
2759 /*-
2760 * https://tools.ietf.org/html/rfc7671#section-5.1
2761 * https://tools.ietf.org/html/rfc7671#section-5.2
2762 * https://tools.ietf.org/html/rfc7671#section-5.3
2763 * https://tools.ietf.org/html/rfc7671#section-5.4
2764 *
2765 * We handle DANE-EE(3) records first as they require no chain building
2766 * and no expiration or hostname checks. We also process digests with
2767 * higher ordinals first and ignore lower priorities except Full(0) which
2768 * is always processed (last). If none match, we then process PKIX-EE(1).
2769 *
2770 * NOTE: This relies on DANE usages sorting before the corresponding PKIX
2771 * usages in SSL_dane_tlsa_add(), and also on descending sorting of digest
2772 * priorities. See twin comment in ssl/ssl_lib.c.
2773 *
2774 * We expect that most TLSA RRsets will have just a single usage, so we
2775 * don't go out of our way to cache multiple selector-specific i2d buffers
2776 * across usages, but if the selector happens to remain the same as switch
2777 * usages, that's OK. Thus, a set of "3 1 1", "3 0 1", "1 1 1", "1 0 1",
2778 * records would result in us generating each of the certificate and public
2779 * key DER forms twice, but more typically we'd just see multiple "3 1 1"
2780 * or multiple "3 0 1" records.
2781 *
2782 * As soon as we find a match at any given depth, we stop, because either
2783 * we've matched a DANE-?? record and the peer is authenticated, or, after
2784 * exhausting all DANE-?? records, we've matched a PKIX-?? record, which is
2785 * sufficient for DANE, and what remains to do is ordinary PKIX validation.
2786 */
2787 recnum = (dane->umask & mask) ? sk_danetls_record_num(dane->trecs) : 0;
2788 for (i = 0; matched == 0 && i < recnum; ++i) {
2789 t = sk_danetls_record_value(dane->trecs, i);
2790 if ((DANETLS_USAGE_BIT(t->usage) & mask) == 0)
2791 continue;
2792 if (t->usage != usage) {
2793 usage = t->usage;
2794
2795 /* Reset digest agility for each usage/selector pair */
2796 mtype = DANETLS_NONE;
2797 ordinal = dane->dctx->mdord[t->mtype];
2798 }
2799 if (t->selector != selector) {
2800 selector = t->selector;
2801
2802 /* Update per-selector state */
2803 OPENSSL_free(i2dbuf);
2804 i2dbuf = dane_i2d(cert, selector, &i2dlen);
2805 if (i2dbuf == NULL)
2806 return -1;
2807
2808 /* Reset digest agility for each usage/selector pair */
2809 mtype = DANETLS_NONE;
2810 ordinal = dane->dctx->mdord[t->mtype];
2811 } else if (t->mtype != DANETLS_MATCHING_FULL) {
2812 /*-
2813 * Digest agility:
2814 *
2815 * <https://tools.ietf.org/html/rfc7671#section-9>
2816 *
2817 * For a fixed selector, after processing all records with the
2818 * highest mtype ordinal, ignore all mtypes with lower ordinals
2819 * other than "Full".
2820 */
2821 if (dane->dctx->mdord[t->mtype] < ordinal)
2822 continue;
2823 }
2824
2825 /*
2826 * Each time we hit a (new selector or) mtype, re-compute the relevant
2827 * digest, more complex caching is not worth the code space.
2828 */
2829 if (t->mtype != mtype) {
2830 const EVP_MD *md = dane->dctx->mdevp[mtype = t->mtype];
2831 cmpbuf = i2dbuf;
2832 cmplen = i2dlen;
2833
2834 if (md != NULL) {
2835 cmpbuf = mdbuf;
2836 if (!EVP_Digest(i2dbuf, i2dlen, cmpbuf, &cmplen, md, 0)) {
2837 matched = -1;
2838 break;
2839 }
2840 }
2841 }
2842
2843 /*
2844 * Squirrel away the certificate and depth if we have a match. Any
2845 * DANE match is dispositive, but with PKIX we still need to build a
2846 * full chain.
2847 */
2848 if (cmplen == t->dlen &&
2849 memcmp(cmpbuf, t->data, cmplen) == 0) {
2850 if (DANETLS_USAGE_BIT(usage) & DANETLS_DANE_MASK)
2851 matched = 1;
2852 if (matched || dane->mdpth < 0) {
2853 dane->mdpth = depth;
2854 dane->mtlsa = t;
2855 OPENSSL_free(dane->mcert);
2856 dane->mcert = cert;
2857 X509_up_ref(cert);
2858 }
2859 break;
2860 }
2861 }
2862
2863 /* Clear the one-element DER cache */
2864 OPENSSL_free(i2dbuf);
2865 return matched;
2866 }
2867
2868 static int check_dane_issuer(X509_STORE_CTX *ctx, int depth)
2869 {
2870 SSL_DANE *dane = ctx->dane;
2871 int matched = 0;
2872 X509 *cert;
2873
2874 if (!DANETLS_HAS_TA(dane) || depth == 0)
2875 return X509_TRUST_UNTRUSTED;
2876
2877 /*
2878 * Record any DANE trust anchor matches, for the first depth to test, if
2879 * there's one at that depth. (This'll be false for length 1 chains looking
2880 * for an exact match for the leaf certificate).
2881 */
2882 cert = sk_X509_value(ctx->chain, depth);
2883 if (cert != NULL && (matched = dane_match(ctx, cert, depth)) < 0)
2884 return X509_TRUST_REJECTED;
2885 if (matched > 0) {
2886 ctx->num_untrusted = depth - 1;
2887 return X509_TRUST_TRUSTED;
2888 }
2889
2890 return X509_TRUST_UNTRUSTED;
2891 }
2892
2893 static int check_dane_pkeys(X509_STORE_CTX *ctx)
2894 {
2895 SSL_DANE *dane = ctx->dane;
2896 danetls_record *t;
2897 int num = ctx->num_untrusted;
2898 X509 *cert = sk_X509_value(ctx->chain, num - 1);
2899 int recnum = sk_danetls_record_num(dane->trecs);
2900 int i;
2901
2902 for (i = 0; i < recnum; ++i) {
2903 t = sk_danetls_record_value(dane->trecs, i);
2904 if (t->usage != DANETLS_USAGE_DANE_TA ||
2905 t->selector != DANETLS_SELECTOR_SPKI ||
2906 t->mtype != DANETLS_MATCHING_FULL ||
2907 X509_verify(cert, t->spki) <= 0)
2908 continue;
2909
2910 /* Clear any PKIX-?? matches that failed to extend to a full chain */
2911 X509_free(dane->mcert);
2912 dane->mcert = NULL;
2913
2914 /* Record match via a bare TA public key */
2915 ctx->bare_ta_signed = 1;
2916 dane->mdpth = num - 1;
2917 dane->mtlsa = t;
2918
2919 /* Prune any excess chain certificates */
2920 num = sk_X509_num(ctx->chain);
2921 for (; num > ctx->num_untrusted; --num)
2922 X509_free(sk_X509_pop(ctx->chain));
2923
2924 return X509_TRUST_TRUSTED;
2925 }
2926
2927 return X509_TRUST_UNTRUSTED;
2928 }
2929
2930 static void dane_reset(SSL_DANE *dane)
2931 {
2932 /*
2933 * Reset state to verify another chain, or clear after failure.
2934 */
2935 X509_free(dane->mcert);
2936 dane->mcert = NULL;
2937 dane->mtlsa = NULL;
2938 dane->mdpth = -1;
2939 dane->pdpth = -1;
2940 }
2941
2942 static int check_leaf_suiteb(X509_STORE_CTX *ctx, X509 *cert)
2943 {
2944 int err = X509_chain_check_suiteb(NULL, cert, NULL, ctx->param->flags);
2945
2946 if (err == X509_V_OK)
2947 return 1;
2948 return verify_cb_cert(ctx, cert, 0, err);
2949 }
2950
2951 static int dane_verify(X509_STORE_CTX *ctx)
2952 {
2953 X509 *cert = ctx->cert;
2954 SSL_DANE *dane = ctx->dane;
2955 int matched;
2956 int done;
2957
2958 dane_reset(dane);
2959
2960 /*-
2961 * When testing the leaf certificate, if we match a DANE-EE(3) record,
2962 * dane_match() returns 1 and we're done. If however we match a PKIX-EE(1)
2963 * record, the match depth and matching TLSA record are recorded, but the
2964 * return value is 0, because we still need to find a PKIX trust anchor.
2965 * Therefore, when DANE authentication is enabled (required), we're done
2966 * if:
2967 * + matched < 0, internal error.
2968 * + matched == 1, we matched a DANE-EE(3) record
2969 * + matched == 0, mdepth < 0 (no PKIX-EE match) and there are no
2970 * DANE-TA(2) or PKIX-TA(0) to test.
2971 */
2972 matched = dane_match(ctx, ctx->cert, 0);
2973 done = matched != 0 || (!DANETLS_HAS_TA(dane) && dane->mdpth < 0);
2974
2975 if (done)
2976 X509_get_pubkey_parameters(NULL, ctx->chain);
2977
2978 if (matched > 0) {
2979 /* Callback invoked as needed */
2980 if (!check_leaf_suiteb(ctx, cert))
2981 return 0;
2982 /* Callback invoked as needed */
2983 if ((dane->flags & DANE_FLAG_NO_DANE_EE_NAMECHECKS) == 0 &&
2984 !check_id(ctx))
2985 return 0;
2986 /* Bypass internal_verify(), issue depth 0 success callback */
2987 ctx->error_depth = 0;
2988 ctx->current_cert = cert;
2989 return ctx->verify_cb(1, ctx);
2990 }
2991
2992 if (matched < 0) {
2993 ctx->error_depth = 0;
2994 ctx->current_cert = cert;
2995 ctx->error = X509_V_ERR_OUT_OF_MEM;
2996 return -1;
2997 }
2998
2999 if (done) {
3000 /* Fail early, TA-based success is not possible */
3001 if (!check_leaf_suiteb(ctx, cert))
3002 return 0;
3003 return verify_cb_cert(ctx, cert, 0, X509_V_ERR_DANE_NO_MATCH);
3004 }
3005
3006 /*
3007 * Chain verification for usages 0/1/2. TLSA record matching of depth > 0
3008 * certificates happens in-line with building the rest of the chain.
3009 */
3010 return verify_chain(ctx);
3011 }
3012
3013 /* Get issuer, without duplicate suppression */
3014 static int get_issuer(X509 **issuer, X509_STORE_CTX *ctx, X509 *cert)
3015 {
3016 STACK_OF(X509) *saved_chain = ctx->chain;
3017 int ok;
3018
3019 ctx->chain = NULL;
3020 ok = ctx->get_issuer(issuer, ctx, cert);
3021 ctx->chain = saved_chain;
3022
3023 return ok;
3024 }
3025
3026 static int build_chain(X509_STORE_CTX *ctx)
3027 {
3028 SSL_DANE *dane = ctx->dane;
3029 int num = sk_X509_num(ctx->chain);
3030 X509 *cert = sk_X509_value(ctx->chain, num - 1);
3031 int self_signed;
3032 STACK_OF(X509) *sktmp = NULL;
3033 unsigned int search;
3034 int may_trusted = 0;
3035 int may_alternate = 0;
3036 int trust = X509_TRUST_UNTRUSTED;
3037 int alt_untrusted = 0;
3038 int depth;
3039 int ok = 0;
3040 int i;
3041
3042 /* Our chain starts with a single untrusted element. */
3043 if (!ossl_assert(num == 1 && ctx->num_untrusted == num)) {
3044 X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
3045 ctx->error = X509_V_ERR_UNSPECIFIED;
3046 return 0;
3047 }
3048
3049 self_signed = X509_self_signed(cert, 0);
3050 if (self_signed < 0) {
3051 ctx->error = X509_V_ERR_UNSPECIFIED;
3052 return 0;
3053 }
3054
3055 #define S_DOUNTRUSTED (1 << 0) /* Search untrusted chain */
3056 #define S_DOTRUSTED (1 << 1) /* Search trusted store */
3057 #define S_DOALTERNATE (1 << 2) /* Retry with pruned alternate chain */
3058 /*
3059 * Set up search policy, untrusted if possible, trusted-first if enabled.
3060 * If we're doing DANE and not doing PKIX-TA/PKIX-EE, we never look in the
3061 * trust_store, otherwise we might look there first. If not trusted-first,
3062 * and alternate chains are not disabled, try building an alternate chain
3063 * if no luck with untrusted first.
3064 */
3065 search = (ctx->untrusted != NULL) ? S_DOUNTRUSTED : 0;
3066 if (DANETLS_HAS_PKIX(dane) || !DANETLS_HAS_DANE(dane)) {
3067 if (search == 0 || ctx->param->flags & X509_V_FLAG_TRUSTED_FIRST)
3068 search |= S_DOTRUSTED;
3069 else if (!(ctx->param->flags & X509_V_FLAG_NO_ALT_CHAINS))
3070 may_alternate = 1;
3071 may_trusted = 1;
3072 }
3073
3074 /*
3075 * Shallow-copy the stack of untrusted certificates (with TLS, this is
3076 * typically the content of the peer's certificate message) so can make
3077 * multiple passes over it, while free to remove elements as we go.
3078 */
3079 if (ctx->untrusted && (sktmp = sk_X509_dup(ctx->untrusted)) == NULL) {
3080 X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
3081 ctx->error = X509_V_ERR_OUT_OF_MEM;
3082 return 0;
3083 }
3084
3085 /*
3086 * If we got any "DANE-TA(2) Cert(0) Full(0)" trust anchors from DNS, add
3087 * them to our working copy of the untrusted certificate stack. Since the
3088 * caller of X509_STORE_CTX_init() may have provided only a leaf cert with
3089 * no corresponding stack of untrusted certificates, we may need to create
3090 * an empty stack first. [ At present only the ssl library provides DANE
3091 * support, and ssl_verify_cert_chain() always provides a non-null stack
3092 * containing at least the leaf certificate, but we must be prepared for
3093 * this to change. ]
3094 */
3095 if (DANETLS_ENABLED(dane) && dane->certs != NULL) {
3096 if (sktmp == NULL && (sktmp = sk_X509_new_null()) == NULL) {
3097 X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
3098 ctx->error = X509_V_ERR_OUT_OF_MEM;
3099 return 0;
3100 }
3101 if (!X509_add_certs(sktmp, dane->certs, X509_ADD_FLAG_DEFAULT)) {
3102 sk_X509_free(sktmp);
3103 ctx->error = X509_V_ERR_OUT_OF_MEM;
3104 return 0;
3105 }
3106 }
3107
3108 /*
3109 * Still absurdly large, but arithmetically safe, a lower hard upper bound
3110 * might be reasonable.
3111 */
3112 if (ctx->param->depth > INT_MAX/2)
3113 ctx->param->depth = INT_MAX/2;
3114
3115 /*
3116 * Try to extend the chain until we reach an ultimately trusted issuer.
3117 * Build chains up to one longer the limit, later fail if we hit the limit,
3118 * with an X509_V_ERR_CERT_CHAIN_TOO_LONG error code.
3119 */
3120 depth = ctx->param->depth + 1;
3121
3122 while (search != 0) {
3123 X509 *x;
3124 X509 *xtmp = NULL;
3125
3126 /*
3127 * Look in the trust store if enabled for first lookup, or we've run
3128 * out of untrusted issuers and search here is not disabled. When we
3129 * reach the depth limit, we stop extending the chain, if by that point
3130 * we've not found a trust anchor, any trusted chain would be too long.
3131 *
3132 * The error reported to the application verify callback is at the
3133 * maximal valid depth with the current certificate equal to the last
3134 * not ultimately-trusted issuer. For example, with verify_depth = 0,
3135 * the callback will report errors at depth=1 when the immediate issuer
3136 * of the leaf certificate is not a trust anchor. No attempt will be
3137 * made to locate an issuer for that certificate, since such a chain
3138 * would be a-priori too long.
3139 */
3140 if ((search & S_DOTRUSTED) != 0) {
3141 i = num = sk_X509_num(ctx->chain);
3142 if ((search & S_DOALTERNATE) != 0) {
3143 /*
3144 * As high up the chain as we can, look for an alternative
3145 * trusted issuer of an untrusted certificate that currently
3146 * has an untrusted issuer. We use the alt_untrusted variable
3147 * to track how far up the chain we find the first match. It
3148 * is only if and when we find a match, that we prune the chain
3149 * and reset ctx->num_untrusted to the reduced count of
3150 * untrusted certificates. While we're searching for such a
3151 * match (which may never be found), it is neither safe nor
3152 * wise to preemptively modify either the chain or
3153 * ctx->num_untrusted.
3154 *
3155 * Note, like ctx->num_untrusted, alt_untrusted is a count of
3156 * untrusted certificates, not a "depth".
3157 */
3158 i = alt_untrusted;
3159 }
3160 x = sk_X509_value(ctx->chain, i-1);
3161
3162 ok = (depth < num) ? 0 : get_issuer(&xtmp, ctx, x);
3163
3164 if (ok < 0) {
3165 trust = X509_TRUST_REJECTED;
3166 ctx->error = X509_V_ERR_STORE_LOOKUP;
3167 search = 0;
3168 continue;
3169 }
3170
3171 if (ok > 0) {
3172 /*
3173 * Alternative trusted issuer for a mid-chain untrusted cert?
3174 * Pop the untrusted cert's successors and retry. We might now
3175 * be able to complete a valid chain via the trust store. Note
3176 * that despite the current trust store match we might still
3177 * fail complete the chain to a suitable trust anchor, in which
3178 * case we may prune some more untrusted certificates and try
3179 * again. Thus the S_DOALTERNATE bit may yet be turned on
3180 * again with an even shorter untrusted chain!
3181 *
3182 * If in the process we threw away our matching PKIX-TA trust
3183 * anchor, reset DANE trust. We might find a suitable trusted
3184 * certificate among the ones from the trust store.
3185 */
3186 if ((search & S_DOALTERNATE) != 0) {
3187 if (!ossl_assert(num > i && i > 0 && !self_signed)) {
3188 X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
3189 X509_free(xtmp);
3190 trust = X509_TRUST_REJECTED;
3191 ctx->error = X509_V_ERR_UNSPECIFIED;
3192 search = 0;
3193 continue;
3194 }
3195 search &= ~S_DOALTERNATE;
3196 for (; num > i; --num)
3197 X509_free(sk_X509_pop(ctx->chain));
3198 ctx->num_untrusted = num;
3199
3200 if (DANETLS_ENABLED(dane) &&
3201 dane->mdpth >= ctx->num_untrusted) {
3202 dane->mdpth = -1;
3203 X509_free(dane->mcert);
3204 dane->mcert = NULL;
3205 }
3206 if (DANETLS_ENABLED(dane) &&
3207 dane->pdpth >= ctx->num_untrusted)
3208 dane->pdpth = -1;
3209 }
3210
3211 /*
3212 * Self-signed untrusted certificates get replaced by their
3213 * trusted matching issuer. Otherwise, grow the chain.
3214 */
3215 if (!self_signed) {
3216 if (!sk_X509_push(ctx->chain, x = xtmp)) {
3217 X509_free(xtmp);
3218 X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
3219 trust = X509_TRUST_REJECTED;
3220 ctx->error = X509_V_ERR_OUT_OF_MEM;
3221 search = 0;
3222 continue;
3223 }
3224 self_signed = X509_self_signed(x, 0);
3225 if (self_signed < 0) {
3226 sk_X509_free(sktmp);
3227 ctx->error = X509_V_ERR_UNSPECIFIED;
3228 return 0;
3229 }
3230 } else if (num == ctx->num_untrusted) {
3231 /*
3232 * We have a self-signed certificate that has the same
3233 * subject name (and perhaps keyid and/or serial number) as
3234 * a trust anchor. We must have an exact match to avoid
3235 * possible impersonation via key substitution etc.
3236 */
3237 if (X509_cmp(x, xtmp) != 0) {
3238 /* Self-signed untrusted mimic. */
3239 X509_free(xtmp);
3240 ok = 0;
3241 } else {
3242 X509_free(x);
3243 ctx->num_untrusted = --num;
3244 (void) sk_X509_set(ctx->chain, num, x = xtmp);
3245 }
3246 }
3247
3248 /*
3249 * We've added a new trusted certificate to the chain, recheck
3250 * trust. If not done, and not self-signed look deeper.
3251 * Whether or not we're doing "trusted first", we no longer
3252 * look for untrusted certificates from the peer's chain.
3253 *
3254 * At this point ctx->num_trusted and num must reflect the
3255 * correct number of untrusted certificates, since the DANE
3256 * logic in check_trust() depends on distinguishing CAs from
3257 * "the wire" from CAs from the trust store. In particular, the
3258 * certificate at depth "num" should be the new trusted
3259 * certificate with ctx->num_untrusted <= num.
3260 */
3261 if (ok) {
3262 if (!ossl_assert(ctx->num_untrusted <= num)) {
3263 X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
3264 trust = X509_TRUST_REJECTED;
3265 ctx->error = X509_V_ERR_UNSPECIFIED;
3266 search = 0;
3267 continue;
3268 }
3269 search &= ~S_DOUNTRUSTED;
3270 switch (trust = check_trust(ctx, num)) {
3271 case X509_TRUST_TRUSTED:
3272 case X509_TRUST_REJECTED:
3273 search = 0;
3274 continue;
3275 }
3276 if (!self_signed)
3277 continue;
3278 }
3279 }
3280
3281 /*
3282 * No dispositive decision, and either self-signed or no match, if
3283 * we were doing untrusted-first, and alt-chains are not disabled,
3284 * do that, by repeatedly losing one untrusted element at a time,
3285 * and trying to extend the shorted chain.
3286 */
3287 if ((search & S_DOUNTRUSTED) == 0) {
3288 /* Continue search for a trusted issuer of a shorter chain? */
3289 if ((search & S_DOALTERNATE) != 0 && --alt_untrusted > 0)
3290 continue;
3291 /* Still no luck and no fallbacks left? */
3292 if (!may_alternate || (search & S_DOALTERNATE) != 0 ||
3293 ctx->num_untrusted < 2)
3294 break;
3295 /* Search for a trusted issuer of a shorter chain */
3296 search |= S_DOALTERNATE;
3297 alt_untrusted = ctx->num_untrusted - 1;
3298 self_signed = 0;
3299 }
3300 }
3301
3302 /*
3303 * Extend chain with peer-provided certificates
3304 */
3305 if ((search & S_DOUNTRUSTED) != 0) {
3306 num = sk_X509_num(ctx->chain);
3307 if (!ossl_assert(num == ctx->num_untrusted)) {
3308 X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
3309 trust = X509_TRUST_REJECTED;
3310 ctx->error = X509_V_ERR_UNSPECIFIED;
3311 search = 0;
3312 continue;
3313 }
3314 x = sk_X509_value(ctx->chain, num-1);
3315
3316 /*
3317 * Once we run out of untrusted issuers, we stop looking for more
3318 * and start looking only in the trust store if enabled.
3319 */
3320 xtmp = (self_signed || depth < num) ? NULL
3321 : find_issuer(ctx, sktmp, x);
3322 if (xtmp == NULL) {
3323 search &= ~S_DOUNTRUSTED;
3324 if (may_trusted)
3325 search |= S_DOTRUSTED;
3326 continue;
3327 }
3328
3329 /* Drop this issuer from future consideration */
3330 (void) sk_X509_delete_ptr(sktmp, xtmp);
3331
3332 if (!X509_up_ref(xtmp)) {
3333 X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
3334 trust = X509_TRUST_REJECTED;
3335 ctx->error = X509_V_ERR_UNSPECIFIED;
3336 search = 0;
3337 continue;
3338 }
3339
3340 if (!sk_X509_push(ctx->chain, xtmp)) {
3341 X509_free(xtmp);
3342 X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
3343 trust = X509_TRUST_REJECTED;
3344 ctx->error = X509_V_ERR_OUT_OF_MEM;
3345 search = 0;
3346 continue;
3347 }
3348
3349 x = xtmp;
3350 ++ctx->num_untrusted;
3351 self_signed = X509_self_signed(xtmp, 0);
3352 if (self_signed < 0) {
3353 sk_X509_free(sktmp);
3354 ctx->error = X509_V_ERR_UNSPECIFIED;
3355 return 0;
3356 }
3357
3358 /*
3359 * Check for DANE-TA trust of the topmost untrusted certificate.
3360 */
3361 switch (trust = check_dane_issuer(ctx, ctx->num_untrusted - 1)) {
3362 case X509_TRUST_TRUSTED:
3363 case X509_TRUST_REJECTED:
3364 search = 0;
3365 continue;
3366 }
3367 }
3368 }
3369 sk_X509_free(sktmp);
3370
3371 /*
3372 * Last chance to make a trusted chain, either bare DANE-TA public-key
3373 * signers, or else direct leaf PKIX trust.
3374 */
3375 num = sk_X509_num(ctx->chain);
3376 if (num <= depth) {
3377 if (trust == X509_TRUST_UNTRUSTED && DANETLS_HAS_DANE_TA(dane))
3378 trust = check_dane_pkeys(ctx);
3379 if (trust == X509_TRUST_UNTRUSTED && num == ctx->num_untrusted)
3380 trust = check_trust(ctx, num);
3381 }
3382
3383 switch (trust) {
3384 case X509_TRUST_TRUSTED:
3385 return 1;
3386 case X509_TRUST_REJECTED:
3387 /* Callback already issued */
3388 return 0;
3389 case X509_TRUST_UNTRUSTED:
3390 default:
3391 num = sk_X509_num(ctx->chain);
3392 if (num > depth)
3393 return verify_cb_cert(ctx, NULL, num-1,
3394 X509_V_ERR_CERT_CHAIN_TOO_LONG);
3395 if (DANETLS_ENABLED(dane) &&
3396 (!DANETLS_HAS_PKIX(dane) || dane->pdpth >= 0))
3397 return verify_cb_cert(ctx, NULL, num-1, X509_V_ERR_DANE_NO_MATCH);
3398 if (self_signed && sk_X509_num(ctx->chain) == 1)
3399 return verify_cb_cert(ctx, NULL, num-1,
3400 X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT);
3401 if (self_signed)
3402 return verify_cb_cert(ctx, NULL, num-1,
3403 X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN);
3404 if (ctx->num_untrusted < num)
3405 return verify_cb_cert(ctx, NULL, num-1,
3406 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT);
3407 return verify_cb_cert(ctx, NULL, num-1,
3408 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY);
3409 }
3410 }
3411
3412 static const int minbits_table[] = { 80, 112, 128, 192, 256 };
3413 static const int NUM_AUTH_LEVELS = OSSL_NELEM(minbits_table);
3414
3415 /*
3416 * Check whether the public key of ``cert`` meets the security level of
3417 * ``ctx``.
3418 *
3419 * Returns 1 on success, 0 otherwise.
3420 */
3421 static int check_key_level(X509_STORE_CTX *ctx, X509 *cert)
3422 {
3423 EVP_PKEY *pkey = X509_get0_pubkey(cert);
3424 int level = ctx->param->auth_level;
3425
3426 /*
3427 * At security level zero, return without checking for a supported public
3428 * key type. Some engines support key types not understood outside the
3429 * engine, and we only need to understand the key when enforcing a security
3430 * floor.
3431 */
3432 if (level <= 0)
3433 return 1;
3434
3435 /* Unsupported or malformed keys are not secure */
3436 if (pkey == NULL)
3437 return 0;
3438
3439 if (level > NUM_AUTH_LEVELS)
3440 level = NUM_AUTH_LEVELS;
3441
3442 return EVP_PKEY_security_bits(pkey) >= minbits_table[level - 1];
3443 }
3444
3445 /*
3446 * Check whether the public key of ``cert`` does not use explicit params
3447 * for an elliptic curve.
3448 *
3449 * Returns 1 on success, 0 if check fails, -1 for other errors.
3450 */
3451 static int check_curve(X509 *cert)
3452 {
3453 #ifndef OPENSSL_NO_EC
3454 EVP_PKEY *pkey = X509_get0_pubkey(cert);
3455
3456 /* Unsupported or malformed key */
3457 if (pkey == NULL)
3458 return -1;
3459
3460 if (EVP_PKEY_id(pkey) == EVP_PKEY_EC) {
3461 int ret;
3462
3463 ret = EC_KEY_decoded_from_explicit_params(EVP_PKEY_get0_EC_KEY(pkey));
3464 return ret < 0 ? ret : !ret;
3465 }
3466 #endif
3467
3468 return 1;
3469 }
3470
3471 /*
3472 * Check whether the signature digest algorithm of ``cert`` meets the security
3473 * level of ``ctx``. Should not be checked for trust anchors (whether
3474 * self-signed or otherwise).
3475 *
3476 * Returns 1 on success, 0 otherwise.
3477 */
3478 static int check_sig_level(X509_STORE_CTX *ctx, X509 *cert)
3479 {
3480 int secbits = -1;
3481 int level = ctx->param->auth_level;
3482
3483 if (level <= 0)
3484 return 1;
3485 if (level > NUM_AUTH_LEVELS)
3486 level = NUM_AUTH_LEVELS;
3487
3488 if (!X509_get_signature_info(cert, NULL, NULL, &secbits, NULL))
3489 return 0;
3490
3491 return secbits >= minbits_table[level - 1];
3492 }
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