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[thirdparty/openssl.git] / crypto / x509 / v3_purp.c
1 /*
2 * Copyright 1999-2020 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 "internal/cryptlib.h"
12 #include "internal/numbers.h"
13 #include <openssl/x509v3.h>
14 #include <openssl/x509_vfy.h>
15 #include "crypto/x509.h"
16 #include "internal/tsan_assist.h"
17 #include "x509_local.h"
18
19 DEFINE_STACK_OF(GENERAL_NAME)
20 DEFINE_STACK_OF(DIST_POINT)
21 DEFINE_STACK_OF(X509_PURPOSE)
22 DEFINE_STACK_OF(ASN1_OBJECT)
23
24 static int check_ssl_ca(const X509 *x);
25 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
26 int ca);
27 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
28 int ca);
29 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
30 int ca);
31 static int purpose_smime(const X509 *x, int ca);
32 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
33 int ca);
34 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
35 int ca);
36 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
37 int ca);
38 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
39 int ca);
40 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
41 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);
42
43 static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b);
44 static void xptable_free(X509_PURPOSE *p);
45
46 static X509_PURPOSE xstandard[] = {
47 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0,
48 check_purpose_ssl_client, "SSL client", "sslclient", NULL},
49 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
50 check_purpose_ssl_server, "SSL server", "sslserver", NULL},
51 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
52 check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
53 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign,
54 "S/MIME signing", "smimesign", NULL},
55 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0,
56 check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
57 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign,
58 "CRL signing", "crlsign", NULL},
59 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any",
60 NULL},
61 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper,
62 "OCSP helper", "ocsphelper", NULL},
63 {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0,
64 check_purpose_timestamp_sign, "Time Stamp signing", "timestampsign",
65 NULL},
66 };
67
68 #define X509_PURPOSE_COUNT OSSL_NELEM(xstandard)
69
70 static STACK_OF(X509_PURPOSE) *xptable = NULL;
71
72 static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b)
73 {
74 return (*a)->purpose - (*b)->purpose;
75 }
76
77 /*
78 * As much as I'd like to make X509_check_purpose use a "const" X509* I
79 * really can't because it does recalculate hashes and do other non-const
80 * things.
81 */
82 int X509_check_purpose(X509 *x, int id, int ca)
83 {
84 int idx;
85 const X509_PURPOSE *pt;
86
87 if (!X509v3_cache_extensions(x, NULL, NULL))
88 return -1;
89
90 /* Return if side-effect only call */
91 if (id == -1)
92 return 1;
93 idx = X509_PURPOSE_get_by_id(id);
94 if (idx == -1)
95 return -1;
96 pt = X509_PURPOSE_get0(idx);
97 return pt->check_purpose(pt, x, ca);
98 }
99
100 int X509_PURPOSE_set(int *p, int purpose)
101 {
102 if (X509_PURPOSE_get_by_id(purpose) == -1) {
103 X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE);
104 return 0;
105 }
106 *p = purpose;
107 return 1;
108 }
109
110 int X509_PURPOSE_get_count(void)
111 {
112 if (!xptable)
113 return X509_PURPOSE_COUNT;
114 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
115 }
116
117 X509_PURPOSE *X509_PURPOSE_get0(int idx)
118 {
119 if (idx < 0)
120 return NULL;
121 if (idx < (int)X509_PURPOSE_COUNT)
122 return xstandard + idx;
123 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
124 }
125
126 int X509_PURPOSE_get_by_sname(const char *sname)
127 {
128 int i;
129 X509_PURPOSE *xptmp;
130 for (i = 0; i < X509_PURPOSE_get_count(); i++) {
131 xptmp = X509_PURPOSE_get0(i);
132 if (strcmp(xptmp->sname, sname) == 0)
133 return i;
134 }
135 return -1;
136 }
137
138 int X509_PURPOSE_get_by_id(int purpose)
139 {
140 X509_PURPOSE tmp;
141 int idx;
142
143 if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
144 return purpose - X509_PURPOSE_MIN;
145 if (xptable == NULL)
146 return -1;
147 tmp.purpose = purpose;
148 idx = sk_X509_PURPOSE_find(xptable, &tmp);
149 if (idx < 0)
150 return -1;
151 return idx + X509_PURPOSE_COUNT;
152 }
153
154 int X509_PURPOSE_add(int id, int trust, int flags,
155 int (*ck) (const X509_PURPOSE *, const X509 *, int),
156 const char *name, const char *sname, void *arg)
157 {
158 int idx;
159 X509_PURPOSE *ptmp;
160 /*
161 * This is set according to what we change: application can't set it
162 */
163 flags &= ~X509_PURPOSE_DYNAMIC;
164 /* This will always be set for application modified trust entries */
165 flags |= X509_PURPOSE_DYNAMIC_NAME;
166 /* Get existing entry if any */
167 idx = X509_PURPOSE_get_by_id(id);
168 /* Need a new entry */
169 if (idx == -1) {
170 if ((ptmp = OPENSSL_malloc(sizeof(*ptmp))) == NULL) {
171 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
172 return 0;
173 }
174 ptmp->flags = X509_PURPOSE_DYNAMIC;
175 } else
176 ptmp = X509_PURPOSE_get0(idx);
177
178 /* OPENSSL_free existing name if dynamic */
179 if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
180 OPENSSL_free(ptmp->name);
181 OPENSSL_free(ptmp->sname);
182 }
183 /* dup supplied name */
184 ptmp->name = OPENSSL_strdup(name);
185 ptmp->sname = OPENSSL_strdup(sname);
186 if (ptmp->name == NULL|| ptmp->sname == NULL) {
187 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
188 goto err;
189 }
190 /* Keep the dynamic flag of existing entry */
191 ptmp->flags &= X509_PURPOSE_DYNAMIC;
192 /* Set all other flags */
193 ptmp->flags |= flags;
194
195 ptmp->purpose = id;
196 ptmp->trust = trust;
197 ptmp->check_purpose = ck;
198 ptmp->usr_data = arg;
199
200 /* If its a new entry manage the dynamic table */
201 if (idx == -1) {
202 if (xptable == NULL
203 && (xptable = sk_X509_PURPOSE_new(xp_cmp)) == NULL) {
204 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
205 goto err;
206 }
207 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
208 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
209 goto err;
210 }
211 }
212 return 1;
213 err:
214 if (idx == -1) {
215 OPENSSL_free(ptmp->name);
216 OPENSSL_free(ptmp->sname);
217 OPENSSL_free(ptmp);
218 }
219 return 0;
220 }
221
222 static void xptable_free(X509_PURPOSE *p)
223 {
224 if (p == NULL)
225 return;
226 if (p->flags & X509_PURPOSE_DYNAMIC) {
227 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
228 OPENSSL_free(p->name);
229 OPENSSL_free(p->sname);
230 }
231 OPENSSL_free(p);
232 }
233 }
234
235 void X509_PURPOSE_cleanup(void)
236 {
237 sk_X509_PURPOSE_pop_free(xptable, xptable_free);
238 xptable = NULL;
239 }
240
241 int X509_PURPOSE_get_id(const X509_PURPOSE *xp)
242 {
243 return xp->purpose;
244 }
245
246 char *X509_PURPOSE_get0_name(const X509_PURPOSE *xp)
247 {
248 return xp->name;
249 }
250
251 char *X509_PURPOSE_get0_sname(const X509_PURPOSE *xp)
252 {
253 return xp->sname;
254 }
255
256 int X509_PURPOSE_get_trust(const X509_PURPOSE *xp)
257 {
258 return xp->trust;
259 }
260
261 static int nid_cmp(const int *a, const int *b)
262 {
263 return *a - *b;
264 }
265
266 DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid);
267 IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid);
268
269 int X509_supported_extension(X509_EXTENSION *ex)
270 {
271 /*
272 * This table is a list of the NIDs of supported extensions: that is
273 * those which are used by the verify process. If an extension is
274 * critical and doesn't appear in this list then the verify process will
275 * normally reject the certificate. The list must be kept in numerical
276 * order because it will be searched using bsearch.
277 */
278
279 static const int supported_nids[] = {
280 NID_netscape_cert_type, /* 71 */
281 NID_key_usage, /* 83 */
282 NID_subject_alt_name, /* 85 */
283 NID_basic_constraints, /* 87 */
284 NID_certificate_policies, /* 89 */
285 NID_crl_distribution_points, /* 103 */
286 NID_ext_key_usage, /* 126 */
287 #ifndef OPENSSL_NO_RFC3779
288 NID_sbgp_ipAddrBlock, /* 290 */
289 NID_sbgp_autonomousSysNum, /* 291 */
290 #endif
291 NID_policy_constraints, /* 401 */
292 NID_proxyCertInfo, /* 663 */
293 NID_name_constraints, /* 666 */
294 NID_policy_mappings, /* 747 */
295 NID_inhibit_any_policy /* 748 */
296 };
297
298 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
299
300 if (ex_nid == NID_undef)
301 return 0;
302
303 if (OBJ_bsearch_nid(&ex_nid, supported_nids, OSSL_NELEM(supported_nids)))
304 return 1;
305 return 0;
306 }
307
308 static int setup_dp(X509 *x, DIST_POINT *dp)
309 {
310 const X509_NAME *iname = NULL;
311 int i;
312
313 if (dp->reasons) {
314 if (dp->reasons->length > 0)
315 dp->dp_reasons = dp->reasons->data[0];
316 if (dp->reasons->length > 1)
317 dp->dp_reasons |= (dp->reasons->data[1] << 8);
318 dp->dp_reasons &= CRLDP_ALL_REASONS;
319 } else
320 dp->dp_reasons = CRLDP_ALL_REASONS;
321 if (!dp->distpoint || (dp->distpoint->type != 1))
322 return 1;
323 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) {
324 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
325 if (gen->type == GEN_DIRNAME) {
326 iname = gen->d.directoryName;
327 break;
328 }
329 }
330 if (!iname)
331 iname = X509_get_issuer_name(x);
332
333 return DIST_POINT_set_dpname(dp->distpoint, iname);
334 }
335
336 static int setup_crldp(X509 *x)
337 {
338 int i;
339
340 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, &i, NULL);
341 if (x->crldp == NULL && i != -1)
342 return 0;
343 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) {
344 if (!setup_dp(x, sk_DIST_POINT_value(x->crldp, i)))
345 return 0;
346 }
347 return 1;
348 }
349
350 /* Check that issuer public key algorithm matches subject signature algorithm */
351 static int check_sig_alg_match(const EVP_PKEY *pkey, const X509 *subject)
352 {
353 int pkey_nid;
354
355 if (pkey == NULL)
356 return X509_V_ERR_NO_ISSUER_PUBLIC_KEY;
357 if (OBJ_find_sigid_algs(OBJ_obj2nid(subject->cert_info.signature.algorithm),
358 NULL, &pkey_nid) == 0)
359 return X509_V_ERR_UNSUPPORTED_SIGNATURE_ALGORITHM;
360 if (EVP_PKEY_type(pkey_nid) != EVP_PKEY_base_id(pkey))
361 return X509_V_ERR_SIGNATURE_ALGORITHM_MISMATCH;
362 return X509_V_OK;
363 }
364
365 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
366 #define ku_reject(x, usage) \
367 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
368 #define xku_reject(x, usage) \
369 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
370 #define ns_reject(x, usage) \
371 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
372
373 /*
374 * Cache info on various X.509v3 extensions and further derived information,
375 * e.g., if cert 'x' is self-issued, in x->ex_flags and other internal fields.
376 * Set EXFLAG_INVALID and return 0 in case the certificate is invalid.
377 */
378 int X509v3_cache_extensions(X509 *x, OPENSSL_CTX *libctx, const char *propq)
379 {
380 BASIC_CONSTRAINTS *bs;
381 PROXY_CERT_INFO_EXTENSION *pci;
382 ASN1_BIT_STRING *usage;
383 ASN1_BIT_STRING *ns;
384 EXTENDED_KEY_USAGE *extusage;
385 X509_EXTENSION *ex;
386 int i;
387 EVP_MD *sha1;
388
389 #ifdef tsan_ld_acq
390 /* fast lock-free check, see end of the function for details. */
391 if (tsan_ld_acq((TSAN_QUALIFIER int *)&x->ex_cached))
392 return (x->ex_flags & EXFLAG_INVALID) == 0;
393 #endif
394
395 CRYPTO_THREAD_write_lock(x->lock);
396 if (x->ex_flags & EXFLAG_SET) { /* cert has already been processed */
397 CRYPTO_THREAD_unlock(x->lock);
398 return (x->ex_flags & EXFLAG_INVALID) == 0;
399 }
400
401 /* Cache the SHA1 digest of the cert */
402 sha1 = EVP_MD_fetch(libctx, "SHA1", propq);
403 if (sha1 != NULL) {
404 if (!X509_digest(x, sha1, x->sha1_hash, NULL))
405 x->ex_flags |= EXFLAG_INVALID;
406 EVP_MD_free(sha1);
407 }
408
409 /* V1 should mean no extensions ... */
410 if (X509_get_version(x) == 0)
411 x->ex_flags |= EXFLAG_V1;
412
413 /* Handle basic constraints */
414 if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, &i, NULL)) != NULL) {
415 if (bs->ca)
416 x->ex_flags |= EXFLAG_CA;
417 if (bs->pathlen != NULL) {
418 if (bs->pathlen->type == V_ASN1_NEG_INTEGER) {
419 x->ex_flags |= EXFLAG_INVALID;
420 x->ex_pathlen = 0;
421 } else {
422 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
423 if (!bs->ca && x->ex_pathlen != 0) {
424 x->ex_flags |= EXFLAG_INVALID;
425 x->ex_pathlen = 0;
426 }
427 }
428 } else {
429 x->ex_pathlen = -1;
430 }
431 BASIC_CONSTRAINTS_free(bs);
432 x->ex_flags |= EXFLAG_BCONS;
433 } else if (i != -1) {
434 x->ex_flags |= EXFLAG_INVALID;
435 }
436
437 /* Handle proxy certificates */
438 if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, &i, NULL)) != NULL) {
439 if (x->ex_flags & EXFLAG_CA
440 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
441 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
442 x->ex_flags |= EXFLAG_INVALID;
443 }
444 if (pci->pcPathLengthConstraint) {
445 x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint);
446 } else
447 x->ex_pcpathlen = -1;
448 PROXY_CERT_INFO_EXTENSION_free(pci);
449 x->ex_flags |= EXFLAG_PROXY;
450 } else if (i != -1) {
451 x->ex_flags |= EXFLAG_INVALID;
452 }
453
454 /* Handle (basic and extended) key usage */
455 if ((usage = X509_get_ext_d2i(x, NID_key_usage, &i, NULL)) != NULL) {
456 x->ex_kusage = 0;
457 if (usage->length > 0) {
458 x->ex_kusage = usage->data[0];
459 if (usage->length > 1)
460 x->ex_kusage |= usage->data[1] << 8;
461 }
462 x->ex_flags |= EXFLAG_KUSAGE;
463 ASN1_BIT_STRING_free(usage);
464 } else if (i != -1) {
465 x->ex_flags |= EXFLAG_INVALID;
466 }
467 x->ex_xkusage = 0;
468 if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, &i, NULL)) != NULL) {
469 x->ex_flags |= EXFLAG_XKUSAGE;
470 for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
471 switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) {
472 case NID_server_auth:
473 x->ex_xkusage |= XKU_SSL_SERVER;
474 break;
475 case NID_client_auth:
476 x->ex_xkusage |= XKU_SSL_CLIENT;
477 break;
478 case NID_email_protect:
479 x->ex_xkusage |= XKU_SMIME;
480 break;
481 case NID_code_sign:
482 x->ex_xkusage |= XKU_CODE_SIGN;
483 break;
484 case NID_ms_sgc:
485 case NID_ns_sgc:
486 x->ex_xkusage |= XKU_SGC;
487 break;
488 case NID_OCSP_sign:
489 x->ex_xkusage |= XKU_OCSP_SIGN;
490 break;
491 case NID_time_stamp:
492 x->ex_xkusage |= XKU_TIMESTAMP;
493 break;
494 case NID_dvcs:
495 x->ex_xkusage |= XKU_DVCS;
496 break;
497 case NID_anyExtendedKeyUsage:
498 x->ex_xkusage |= XKU_ANYEKU;
499 break;
500 default:
501 break;
502 }
503 }
504 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
505 } else if (i != -1) {
506 x->ex_flags |= EXFLAG_INVALID;
507 }
508
509 /* Handle legacy Netscape extension */
510 if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, &i, NULL)) != NULL) {
511 if (ns->length > 0)
512 x->ex_nscert = ns->data[0];
513 else
514 x->ex_nscert = 0;
515 x->ex_flags |= EXFLAG_NSCERT;
516 ASN1_BIT_STRING_free(ns);
517 } else if (i != -1) {
518 x->ex_flags |= EXFLAG_INVALID;
519 }
520
521 /* Handle subject key identifier and issuer/authority key identifier */
522 x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, &i, NULL);
523 if (x->skid == NULL && i != -1)
524 x->ex_flags |= EXFLAG_INVALID;
525 x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, &i, NULL);
526 if (x->akid == NULL && i != -1)
527 x->ex_flags |= EXFLAG_INVALID;
528
529 /* Check if subject name matches issuer */
530 if (X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)) == 0) {
531 x->ex_flags |= EXFLAG_SI; /* cert is self-issued */
532 if (X509_check_akid(x, x->akid) == X509_V_OK /* SKID matches AKID */
533 /* .. and the signature alg matches the PUBKEY alg: */
534 && check_sig_alg_match(X509_get0_pubkey(x), x) == X509_V_OK)
535 x->ex_flags |= EXFLAG_SS; /* indicate self-signed */
536 }
537
538 /* Handle subject alternative names and various other extensions */
539 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, &i, NULL);
540 if (x->altname == NULL && i != -1)
541 x->ex_flags |= EXFLAG_INVALID;
542 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL);
543 if (x->nc == NULL && i != -1)
544 x->ex_flags |= EXFLAG_INVALID;
545 if (!setup_crldp(x))
546 x->ex_flags |= EXFLAG_INVALID;
547
548 #ifndef OPENSSL_NO_RFC3779
549 x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, &i, NULL);
550 if (x->rfc3779_addr == NULL && i != -1)
551 x->ex_flags |= EXFLAG_INVALID;
552 x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum, &i, NULL);
553 if (x->rfc3779_asid == NULL && i != -1)
554 x->ex_flags |= EXFLAG_INVALID;
555 #endif
556 for (i = 0; i < X509_get_ext_count(x); i++) {
557 ex = X509_get_ext(x, i);
558 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
559 == NID_freshest_crl)
560 x->ex_flags |= EXFLAG_FRESHEST;
561 if (!X509_EXTENSION_get_critical(ex))
562 continue;
563 if (!X509_supported_extension(ex)) {
564 x->ex_flags |= EXFLAG_CRITICAL;
565 break;
566 }
567 }
568
569 x509_init_sig_info(x);
570
571 x->ex_flags |= EXFLAG_SET; /* indicate that cert has been processed */
572 #ifdef tsan_st_rel
573 tsan_st_rel((TSAN_QUALIFIER int *)&x->ex_cached, 1);
574 /*
575 * Above store triggers fast lock-free check in the beginning of the
576 * function. But one has to ensure that the structure is "stable", i.e.
577 * all stores are visible on all processors. Hence the release fence.
578 */
579 #endif
580 CRYPTO_THREAD_unlock(x->lock);
581
582 return (x->ex_flags & EXFLAG_INVALID) == 0;
583 }
584
585 /*-
586 * CA checks common to all purposes
587 * return codes:
588 * 0 not a CA
589 * 1 is a CA
590 * 2 Only possible in older versions of openSSL when basicConstraints are absent
591 * new versions will not return this value. May be a CA
592 * 3 basicConstraints absent but self-signed V1.
593 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
594 * 5 Netscape specific CA Flags present
595 */
596
597 static int check_ca(const X509 *x)
598 {
599 /* keyUsage if present should allow cert signing */
600 if (ku_reject(x, KU_KEY_CERT_SIGN))
601 return 0;
602 if (x->ex_flags & EXFLAG_BCONS) {
603 if (x->ex_flags & EXFLAG_CA)
604 return 1;
605 /* If basicConstraints says not a CA then say so */
606 else
607 return 0;
608 } else {
609 /* we support V1 roots for... uh, I don't really know why. */
610 if ((x->ex_flags & V1_ROOT) == V1_ROOT)
611 return 3;
612 /*
613 * If key usage present it must have certSign so tolerate it
614 */
615 else if (x->ex_flags & EXFLAG_KUSAGE)
616 return 4;
617 /* Older certificates could have Netscape-specific CA types */
618 else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA)
619 return 5;
620 /* can this still be regarded a CA certificate? I doubt it */
621 return 0;
622 }
623 }
624
625 void X509_set_proxy_flag(X509 *x)
626 {
627 x->ex_flags |= EXFLAG_PROXY;
628 }
629
630 void X509_set_proxy_pathlen(X509 *x, long l)
631 {
632 x->ex_pcpathlen = l;
633 }
634
635 int X509_check_ca(X509 *x)
636 {
637 /* Note 0 normally means "not a CA" - but in this case means error. */
638 if (!X509v3_cache_extensions(x, NULL, NULL))
639 return 0;
640
641 return check_ca(x);
642 }
643
644 /* Check SSL CA: common checks for SSL client and server */
645 static int check_ssl_ca(const X509 *x)
646 {
647 int ca_ret;
648 ca_ret = check_ca(x);
649 if (!ca_ret)
650 return 0;
651 /* check nsCertType if present */
652 if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA)
653 return ca_ret;
654 else
655 return 0;
656 }
657
658 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
659 int ca)
660 {
661 if (xku_reject(x, XKU_SSL_CLIENT))
662 return 0;
663 if (ca)
664 return check_ssl_ca(x);
665 /* We need to do digital signatures or key agreement */
666 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_AGREEMENT))
667 return 0;
668 /* nsCertType if present should allow SSL client use */
669 if (ns_reject(x, NS_SSL_CLIENT))
670 return 0;
671 return 1;
672 }
673
674 /*
675 * Key usage needed for TLS/SSL server: digital signature, encipherment or
676 * key agreement. The ssl code can check this more thoroughly for individual
677 * key types.
678 */
679 #define KU_TLS \
680 KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT
681
682 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
683 int ca)
684 {
685 if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC))
686 return 0;
687 if (ca)
688 return check_ssl_ca(x);
689
690 if (ns_reject(x, NS_SSL_SERVER))
691 return 0;
692 if (ku_reject(x, KU_TLS))
693 return 0;
694
695 return 1;
696
697 }
698
699 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
700 int ca)
701 {
702 int ret;
703 ret = check_purpose_ssl_server(xp, x, ca);
704 if (!ret || ca)
705 return ret;
706 /* We need to encipher or Netscape complains */
707 if (ku_reject(x, KU_KEY_ENCIPHERMENT))
708 return 0;
709 return ret;
710 }
711
712 /* common S/MIME checks */
713 static int purpose_smime(const X509 *x, int ca)
714 {
715 if (xku_reject(x, XKU_SMIME))
716 return 0;
717 if (ca) {
718 int ca_ret;
719 ca_ret = check_ca(x);
720 if (!ca_ret)
721 return 0;
722 /* check nsCertType if present */
723 if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA)
724 return ca_ret;
725 else
726 return 0;
727 }
728 if (x->ex_flags & EXFLAG_NSCERT) {
729 if (x->ex_nscert & NS_SMIME)
730 return 1;
731 /* Workaround for some buggy certificates */
732 if (x->ex_nscert & NS_SSL_CLIENT)
733 return 2;
734 return 0;
735 }
736 return 1;
737 }
738
739 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
740 int ca)
741 {
742 int ret;
743 ret = purpose_smime(x, ca);
744 if (!ret || ca)
745 return ret;
746 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION))
747 return 0;
748 return ret;
749 }
750
751 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
752 int ca)
753 {
754 int ret;
755 ret = purpose_smime(x, ca);
756 if (!ret || ca)
757 return ret;
758 if (ku_reject(x, KU_KEY_ENCIPHERMENT))
759 return 0;
760 return ret;
761 }
762
763 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
764 int ca)
765 {
766 if (ca) {
767 int ca_ret;
768 if ((ca_ret = check_ca(x)) != 2)
769 return ca_ret;
770 else
771 return 0;
772 }
773 if (ku_reject(x, KU_CRL_SIGN))
774 return 0;
775 return 1;
776 }
777
778 /*
779 * OCSP helper: this is *not* a full OCSP check. It just checks that each CA
780 * is valid. Additional checks must be made on the chain.
781 */
782
783 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
784 {
785 /*
786 * Must be a valid CA. Should we really support the "I don't know" value
787 * (2)?
788 */
789 if (ca)
790 return check_ca(x);
791 /* leaf certificate is checked in OCSP_verify() */
792 return 1;
793 }
794
795 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
796 int ca)
797 {
798 int i_ext;
799
800 /* If ca is true we must return if this is a valid CA certificate. */
801 if (ca)
802 return check_ca(x);
803
804 /*
805 * Check the optional key usage field:
806 * if Key Usage is present, it must be one of digitalSignature
807 * and/or nonRepudiation (other values are not consistent and shall
808 * be rejected).
809 */
810 if ((x->ex_flags & EXFLAG_KUSAGE)
811 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
812 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
813 return 0;
814
815 /* Only time stamp key usage is permitted and it's required. */
816 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
817 return 0;
818
819 /* Extended Key Usage MUST be critical */
820 i_ext = X509_get_ext_by_NID(x, NID_ext_key_usage, -1);
821 if (i_ext >= 0) {
822 X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext);
823 if (!X509_EXTENSION_get_critical(ext))
824 return 0;
825 }
826
827 return 1;
828 }
829
830 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
831 {
832 return 1;
833 }
834
835 /*-
836 * Various checks to see if one certificate potentially issued the second.
837 * This can be used to prune a set of possible issuer certificates which
838 * have been looked up using some simple method such as by subject name.
839 * These are:
840 * 1. Check issuer_name(subject) == subject_name(issuer)
841 * 2. If akid(subject) exists, check that it matches issuer
842 * 3. Check that issuer public key algorithm matches subject signature algorithm
843 * 4. Check that any key_usage(issuer) allows certificate signing
844 * Note that this does not include actually checking the signature.
845 * Returns 0 for OK, or positive for reason for mismatch
846 * where reason codes match those for X509_verify_cert().
847 */
848 int x509_check_issued_int(X509 *issuer, X509 *subject,
849 OPENSSL_CTX *libctx, const char *propq)
850 {
851 int ret;
852
853 if ((ret = x509_likely_issued(issuer, subject, libctx, propq)) != X509_V_OK)
854 return ret;
855 return x509_signing_allowed(issuer, subject);
856 }
857
858 /* do the checks 1., 2., and 3. as described above for X509_check_issued() */
859 int x509_likely_issued(X509 *issuer, X509 *subject,
860 OPENSSL_CTX *libctx, const char *propq)
861 {
862 int ret;
863
864 if (X509_NAME_cmp(X509_get_subject_name(issuer),
865 X509_get_issuer_name(subject)) != 0)
866 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
867
868 if (!X509v3_cache_extensions(issuer, libctx, propq)
869 || !X509v3_cache_extensions(subject, libctx, propq))
870 return X509_V_ERR_UNSPECIFIED;
871
872 ret = X509_check_akid(issuer, subject->akid);
873 if (ret != X509_V_OK)
874 return ret;
875
876 /* check if the subject signature alg matches the issuer's PUBKEY alg */
877 return check_sig_alg_match(X509_get0_pubkey(issuer), subject);
878 }
879
880 /*-
881 * Check if certificate I<issuer> is allowed to issue certificate I<subject>
882 * according to the B<keyUsage> field of I<issuer> if present
883 * depending on any proxyCertInfo extension of I<subject>.
884 * Returns 0 for OK, or positive for reason for rejection
885 * where reason codes match those for X509_verify_cert().
886 */
887 int x509_signing_allowed(const X509 *issuer, const X509 *subject)
888 {
889 if (subject->ex_flags & EXFLAG_PROXY) {
890 if (ku_reject(issuer, KU_DIGITAL_SIGNATURE))
891 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
892 } else if (ku_reject(issuer, KU_KEY_CERT_SIGN))
893 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
894 return X509_V_OK;
895 }
896
897 int X509_check_issued(X509 *issuer, X509 *subject)
898 {
899 return x509_check_issued_int(issuer, subject, NULL, NULL);
900 }
901
902 int X509_check_akid(const X509 *issuer, const AUTHORITY_KEYID *akid)
903 {
904 if (akid == NULL)
905 return X509_V_OK;
906
907 /* Check key ids (if present) */
908 if (akid->keyid && issuer->skid &&
909 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid))
910 return X509_V_ERR_AKID_SKID_MISMATCH;
911 /* Check serial number */
912 if (akid->serial &&
913 ASN1_INTEGER_cmp(X509_get0_serialNumber(issuer), akid->serial))
914 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
915 /* Check issuer name */
916 if (akid->issuer) {
917 /*
918 * Ugh, for some peculiar reason AKID includes SEQUENCE OF
919 * GeneralName. So look for a DirName. There may be more than one but
920 * we only take any notice of the first.
921 */
922 GENERAL_NAMES *gens;
923 GENERAL_NAME *gen;
924 X509_NAME *nm = NULL;
925 int i;
926 gens = akid->issuer;
927 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
928 gen = sk_GENERAL_NAME_value(gens, i);
929 if (gen->type == GEN_DIRNAME) {
930 nm = gen->d.dirn;
931 break;
932 }
933 }
934 if (nm != NULL && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)) != 0)
935 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
936 }
937 return X509_V_OK;
938 }
939
940 uint32_t X509_get_extension_flags(X509 *x)
941 {
942 /* Call for side-effect of computing hash and caching extensions */
943 X509_check_purpose(x, -1, -1);
944 return x->ex_flags;
945 }
946
947 uint32_t X509_get_key_usage(X509 *x)
948 {
949 /* Call for side-effect of computing hash and caching extensions */
950 if (X509_check_purpose(x, -1, -1) != 1)
951 return 0;
952 if (x->ex_flags & EXFLAG_KUSAGE)
953 return x->ex_kusage;
954 return UINT32_MAX;
955 }
956
957 uint32_t X509_get_extended_key_usage(X509 *x)
958 {
959 /* Call for side-effect of computing hash and caching extensions */
960 if (X509_check_purpose(x, -1, -1) != 1)
961 return 0;
962 if (x->ex_flags & EXFLAG_XKUSAGE)
963 return x->ex_xkusage;
964 return UINT32_MAX;
965 }
966
967 const ASN1_OCTET_STRING *X509_get0_subject_key_id(X509 *x)
968 {
969 /* Call for side-effect of computing hash and caching extensions */
970 if (X509_check_purpose(x, -1, -1) != 1)
971 return NULL;
972 return x->skid;
973 }
974
975 const ASN1_OCTET_STRING *X509_get0_authority_key_id(X509 *x)
976 {
977 /* Call for side-effect of computing hash and caching extensions */
978 if (X509_check_purpose(x, -1, -1) != 1)
979 return NULL;
980 return (x->akid != NULL ? x->akid->keyid : NULL);
981 }
982
983 const GENERAL_NAMES *X509_get0_authority_issuer(X509 *x)
984 {
985 /* Call for side-effect of computing hash and caching extensions */
986 if (X509_check_purpose(x, -1, -1) != 1)
987 return NULL;
988 return (x->akid != NULL ? x->akid->issuer : NULL);
989 }
990
991 const ASN1_INTEGER *X509_get0_authority_serial(X509 *x)
992 {
993 /* Call for side-effect of computing hash and caching extensions */
994 if (X509_check_purpose(x, -1, -1) != 1)
995 return NULL;
996 return (x->akid != NULL ? x->akid->serial : NULL);
997 }
998
999 long X509_get_pathlen(X509 *x)
1000 {
1001 /* Called for side effect of caching extensions */
1002 if (X509_check_purpose(x, -1, -1) != 1
1003 || (x->ex_flags & EXFLAG_BCONS) == 0)
1004 return -1;
1005 return x->ex_pathlen;
1006 }
1007
1008 long X509_get_proxy_pathlen(X509 *x)
1009 {
1010 /* Called for side effect of caching extensions */
1011 if (X509_check_purpose(x, -1, -1) != 1
1012 || (x->ex_flags & EXFLAG_PROXY) == 0)
1013 return -1;
1014 return x->ex_pcpathlen;
1015 }
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