1 /*
2 * Copyright 2001-2022 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 <string.h>
11 #include <openssl/ocsp.h>
12 #include <openssl/err.h>
13 #include "internal/sizes.h"
14 #include "ocsp_local.h"
15
16 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
17 STACK_OF(X509) *certs, unsigned long flags);
18 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
19 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain);
20 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp,
21 OCSP_CERTID **ret);
22 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
23 STACK_OF(OCSP_SINGLERESP) *sresp);
24 static int ocsp_check_delegated(X509 *x);
25 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req,
26 const X509_NAME *nm, STACK_OF(X509) *certs,
27 unsigned long flags);
28
29 /* Returns 1 on success, 0 on failure, or -1 on fatal error */
ocsp_verify_signer(X509 * signer,int response,X509_STORE * st,unsigned long flags,STACK_OF (X509)* untrusted,STACK_OF (X509)** chain)30 static int ocsp_verify_signer(X509 *signer, int response,
31 X509_STORE *st, unsigned long flags,
32 STACK_OF(X509) *untrusted, STACK_OF(X509) **chain)
33 {
34 X509_STORE_CTX *ctx = X509_STORE_CTX_new();
35 X509_VERIFY_PARAM *vp;
36 int ret = -1;
37
38 if (ctx == NULL) {
39 ERR_raise(ERR_LIB_OCSP, ERR_R_MALLOC_FAILURE);
40 goto end;
41 }
42 if (!X509_STORE_CTX_init(ctx, st, signer, untrusted)) {
43 ERR_raise(ERR_LIB_OCSP, ERR_R_X509_LIB);
44 goto end;
45 }
46 if ((vp = X509_STORE_CTX_get0_param(ctx)) == NULL)
47 goto end;
48 if ((flags & OCSP_PARTIAL_CHAIN) != 0)
49 X509_VERIFY_PARAM_set_flags(vp, X509_V_FLAG_PARTIAL_CHAIN);
50 if (response
51 && X509_get_ext_by_NID(signer, NID_id_pkix_OCSP_noCheck, -1) >= 0)
52 /*
53 * Locally disable revocation status checking for OCSP responder cert.
54 * Done here for CRLs; should be done also for OCSP-based checks.
55 */
56 X509_VERIFY_PARAM_clear_flags(vp, X509_V_FLAG_CRL_CHECK);
57 X509_STORE_CTX_set_purpose(ctx, X509_PURPOSE_OCSP_HELPER);
58 X509_STORE_CTX_set_trust(ctx, X509_TRUST_OCSP_REQUEST);
59
60 ret = X509_verify_cert(ctx);
61 if (ret <= 0) {
62 int err = X509_STORE_CTX_get_error(ctx);
63
64 ERR_raise_data(ERR_LIB_OCSP, OCSP_R_CERTIFICATE_VERIFY_ERROR,
65 "Verify error: %s", X509_verify_cert_error_string(err));
66 goto end;
67 }
68 if (chain != NULL)
69 *chain = X509_STORE_CTX_get1_chain(ctx);
70
71 end:
72 X509_STORE_CTX_free(ctx);
73 return ret;
74 }
75
ocsp_verify(OCSP_REQUEST * req,OCSP_BASICRESP * bs,X509 * signer,unsigned long flags)76 static int ocsp_verify(OCSP_REQUEST *req, OCSP_BASICRESP *bs,
77 X509 *signer, unsigned long flags)
78 {
79 EVP_PKEY *skey;
80 int ret = 1;
81
82 if ((flags & OCSP_NOSIGS) == 0) {
83 if ((skey = X509_get0_pubkey(signer)) == NULL) {
84 ERR_raise(ERR_LIB_OCSP, OCSP_R_NO_SIGNER_KEY);
85 return -1;
86 }
87 if (req != NULL)
88 ret = OCSP_REQUEST_verify(req, skey, signer->libctx, signer->propq);
89 else
90 ret = OCSP_BASICRESP_verify(bs, skey, signer->libctx, signer->propq);
91 if (ret <= 0)
92 ERR_raise(ERR_LIB_OCSP, OCSP_R_SIGNATURE_FAILURE);
93 }
94 return ret;
95 }
96
97 /* Verify a basic response message */
OCSP_basic_verify(OCSP_BASICRESP * bs,STACK_OF (X509)* certs,X509_STORE * st,unsigned long flags)98 int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
99 X509_STORE *st, unsigned long flags)
100 {
101 X509 *signer, *x;
102 STACK_OF(X509) *chain = NULL;
103 STACK_OF(X509) *untrusted = NULL;
104 int ret = ocsp_find_signer(&signer, bs, certs, flags);
105
106 if (ret == 0) {
107 ERR_raise(ERR_LIB_OCSP, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
108 goto end;
109 }
110 if ((ret == 2) && (flags & OCSP_TRUSTOTHER) != 0)
111 flags |= OCSP_NOVERIFY;
112
113 if ((ret = ocsp_verify(NULL, bs, signer, flags)) <= 0)
114 goto end;
115 if ((flags & OCSP_NOVERIFY) == 0) {
116 ret = -1;
117 if ((flags & OCSP_NOCHAIN) == 0) {
118 if ((untrusted = sk_X509_dup(bs->certs)) == NULL)
119 goto end;
120 if (!X509_add_certs(untrusted, certs, X509_ADD_FLAG_DEFAULT))
121 goto end;
122 }
123 ret = ocsp_verify_signer(signer, 1, st, flags, untrusted, &chain);
124 if (ret <= 0)
125 goto end;
126 if ((flags & OCSP_NOCHECKS) != 0) {
127 ret = 1;
128 goto end;
129 }
130 /*
131 * At this point we have a valid certificate chain need to verify it
132 * against the OCSP issuer criteria.
133 */
134 ret = ocsp_check_issuer(bs, chain);
135
136 /* If fatal error or valid match then finish */
137 if (ret != 0)
138 goto end;
139
140 /*
141 * Easy case: explicitly trusted. Get root CA and check for explicit
142 * trust
143 */
144 if ((flags & OCSP_NOEXPLICIT) != 0)
145 goto end;
146
147 x = sk_X509_value(chain, sk_X509_num(chain) - 1);
148 if (X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED) {
149 ERR_raise(ERR_LIB_OCSP, OCSP_R_ROOT_CA_NOT_TRUSTED);
150 ret = 0;
151 goto end;
152 }
153 ret = 1;
154 }
155
156 end:
157 sk_X509_pop_free(chain, X509_free);
158 sk_X509_free(untrusted);
159 return ret;
160 }
161
OCSP_resp_get0_signer(OCSP_BASICRESP * bs,X509 ** signer,STACK_OF (X509)* extra_certs)162 int OCSP_resp_get0_signer(OCSP_BASICRESP *bs, X509 **signer,
163 STACK_OF(X509) *extra_certs)
164 {
165 return ocsp_find_signer(signer, bs, extra_certs, 0) > 0;
166 }
167
ocsp_find_signer(X509 ** psigner,OCSP_BASICRESP * bs,STACK_OF (X509)* certs,unsigned long flags)168 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
169 STACK_OF(X509) *certs, unsigned long flags)
170 {
171 X509 *signer;
172 OCSP_RESPID *rid = &bs->tbsResponseData.responderId;
173
174 if ((signer = ocsp_find_signer_sk(certs, rid)) != NULL) {
175 *psigner = signer;
176 return 2;
177 }
178 if ((flags & OCSP_NOINTERN) == 0 &&
179 (signer = ocsp_find_signer_sk(bs->certs, rid))) {
180 *psigner = signer;
181 return 1;
182 }
183 /* Maybe lookup from store if by subject name */
184
185 *psigner = NULL;
186 return 0;
187 }
188
ocsp_find_signer_sk(STACK_OF (X509)* certs,OCSP_RESPID * id)189 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
190 {
191 int i, r;
192 unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
193 EVP_MD *md;
194 X509 *x;
195
196 /* Easy if lookup by name */
197 if (id->type == V_OCSP_RESPID_NAME)
198 return X509_find_by_subject(certs, id->value.byName);
199
200 /* Lookup by key hash */
201
202 /* If key hash isn't SHA1 length then forget it */
203 if (id->value.byKey->length != SHA_DIGEST_LENGTH)
204 return NULL;
205 keyhash = id->value.byKey->data;
206 /* Calculate hash of each key and compare */
207 for (i = 0; i < sk_X509_num(certs); i++) {
208 if ((x = sk_X509_value(certs, i)) != NULL) {
209 if ((md = EVP_MD_fetch(x->libctx, SN_sha1, x->propq)) == NULL)
210 break;
211 r = X509_pubkey_digest(x, md, tmphash, NULL);
212 EVP_MD_free(md);
213 if (!r)
214 break;
215 if (memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH) == 0)
216 return x;
217 }
218 }
219 return NULL;
220 }
221
ocsp_check_issuer(OCSP_BASICRESP * bs,STACK_OF (X509)* chain)222 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain)
223 {
224 STACK_OF(OCSP_SINGLERESP) *sresp = bs->tbsResponseData.responses;
225 X509 *signer, *sca;
226 OCSP_CERTID *caid = NULL;
227 int ret;
228
229 if (sk_X509_num(chain) <= 0) {
230 ERR_raise(ERR_LIB_OCSP, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
231 return -1;
232 }
233
234 /* See if the issuer IDs match. */
235 ret = ocsp_check_ids(sresp, &caid);
236
237 /* If ID mismatch or other error then return */
238 if (ret <= 0)
239 return ret;
240
241 signer = sk_X509_value(chain, 0);
242 /* Check to see if OCSP responder CA matches request CA */
243 if (sk_X509_num(chain) > 1) {
244 sca = sk_X509_value(chain, 1);
245 ret = ocsp_match_issuerid(sca, caid, sresp);
246 if (ret < 0)
247 return ret;
248 if (ret != 0) {
249 /* We have a match, if extensions OK then success */
250 if (ocsp_check_delegated(signer))
251 return 1;
252 return 0;
253 }
254 }
255
256 /* Otherwise check if OCSP request signed directly by request CA */
257 return ocsp_match_issuerid(signer, caid, sresp);
258 }
259
260 /*
261 * Check the issuer certificate IDs for equality. If there is a mismatch with
262 * the same algorithm then there's no point trying to match any certificates
263 * against the issuer. If the issuer IDs all match then we just need to check
264 * equality against one of them.
265 */
266
ocsp_check_ids(STACK_OF (OCSP_SINGLERESP)* sresp,OCSP_CERTID ** ret)267 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
268 {
269 OCSP_CERTID *tmpid, *cid;
270 int i, idcount;
271
272 idcount = sk_OCSP_SINGLERESP_num(sresp);
273 if (idcount <= 0) {
274 ERR_raise(ERR_LIB_OCSP, OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
275 return -1;
276 }
277
278 cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
279
280 *ret = NULL;
281 for (i = 1; i < idcount; i++) {
282 tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
283 /* Check to see if IDs match */
284 if (OCSP_id_issuer_cmp(cid, tmpid)) {
285 /* If algorithm mismatch let caller deal with it */
286 if (OBJ_cmp(tmpid->hashAlgorithm.algorithm,
287 cid->hashAlgorithm.algorithm))
288 return 2;
289 /* Else mismatch */
290 return 0;
291 }
292 }
293
294 /* All IDs match: only need to check one ID */
295 *ret = cid;
296 return 1;
297 }
298
299 /*
300 * Match the certificate issuer ID.
301 * Returns -1 on fatal error, 0 if there is no match and 1 if there is a match.
302 */
ocsp_match_issuerid(X509 * cert,OCSP_CERTID * cid,STACK_OF (OCSP_SINGLERESP)* sresp)303 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
304 STACK_OF(OCSP_SINGLERESP) *sresp)
305 {
306 int ret = -1;
307 EVP_MD *dgst = NULL;
308
309 /* If only one ID to match then do it */
310 if (cid != NULL) {
311 char name[OSSL_MAX_NAME_SIZE];
312 const X509_NAME *iname;
313 int mdlen;
314 unsigned char md[EVP_MAX_MD_SIZE];
315
316 OBJ_obj2txt(name, sizeof(name), cid->hashAlgorithm.algorithm, 0);
317
318 (void)ERR_set_mark();
319 dgst = EVP_MD_fetch(NULL, name, NULL);
320 if (dgst == NULL)
321 dgst = (EVP_MD *)EVP_get_digestbyname(name);
322
323 if (dgst == NULL) {
324 (void)ERR_clear_last_mark();
325 ERR_raise(ERR_LIB_OCSP, OCSP_R_UNKNOWN_MESSAGE_DIGEST);
326 goto end;
327 }
328 (void)ERR_pop_to_mark();
329
330 mdlen = EVP_MD_get_size(dgst);
331 if (mdlen < 0) {
332 ERR_raise(ERR_LIB_OCSP, OCSP_R_DIGEST_SIZE_ERR);
333 goto end;
334 }
335 if (cid->issuerNameHash.length != mdlen ||
336 cid->issuerKeyHash.length != mdlen) {
337 ret = 0;
338 goto end;
339 }
340 iname = X509_get_subject_name(cert);
341 if (!X509_NAME_digest(iname, dgst, md, NULL))
342 goto end;
343 if (memcmp(md, cid->issuerNameHash.data, mdlen) != 0) {
344 ret = 0;
345 goto end;
346 }
347 if (!X509_pubkey_digest(cert, dgst, md, NULL)) {
348 ERR_raise(ERR_LIB_OCSP, OCSP_R_DIGEST_ERR);
349 goto end;
350 }
351 ret = memcmp(md, cid->issuerKeyHash.data, mdlen) == 0;
352 goto end;
353 } else {
354 /* We have to match the whole lot */
355 int i;
356 OCSP_CERTID *tmpid;
357
358 for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++) {
359 tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
360 ret = ocsp_match_issuerid(cert, tmpid, NULL);
361 if (ret <= 0)
362 return ret;
363 }
364 }
365 return 1;
366 end:
367 EVP_MD_free(dgst);
368 return ret;
369 }
370
ocsp_check_delegated(X509 * x)371 static int ocsp_check_delegated(X509 *x)
372 {
373 if ((X509_get_extension_flags(x) & EXFLAG_XKUSAGE)
374 && (X509_get_extended_key_usage(x) & XKU_OCSP_SIGN))
375 return 1;
376 ERR_raise(ERR_LIB_OCSP, OCSP_R_MISSING_OCSPSIGNING_USAGE);
377 return 0;
378 }
379
380 /*
381 * Verify an OCSP request. This is much easier than OCSP response verify.
382 * Just find the signer's certificate and verify it against a given trust value.
383 * Returns 1 on success, 0 on failure and on fatal error.
384 */
OCSP_request_verify(OCSP_REQUEST * req,STACK_OF (X509)* certs,X509_STORE * store,unsigned long flags)385 int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs,
386 X509_STORE *store, unsigned long flags)
387 {
388 X509 *signer;
389 const X509_NAME *nm;
390 GENERAL_NAME *gen;
391 int ret;
392
393 if (!req->optionalSignature) {
394 ERR_raise(ERR_LIB_OCSP, OCSP_R_REQUEST_NOT_SIGNED);
395 return 0;
396 }
397 gen = req->tbsRequest.requestorName;
398 if (!gen || gen->type != GEN_DIRNAME) {
399 ERR_raise(ERR_LIB_OCSP, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
400 return 0; /* not returning -1 here for backward compatibility*/
401 }
402 nm = gen->d.directoryName;
403 ret = ocsp_req_find_signer(&signer, req, nm, certs, flags);
404 if (ret <= 0) {
405 ERR_raise(ERR_LIB_OCSP, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
406 return 0; /* not returning -1 here for backward compatibility*/
407 }
408 if ((ret == 2) && (flags & OCSP_TRUSTOTHER) != 0)
409 flags |= OCSP_NOVERIFY;
410
411 if ((ret = ocsp_verify(req, NULL, signer, flags)) <= 0)
412 return 0; /* not returning 'ret' here for backward compatibility*/
413 if ((flags & OCSP_NOVERIFY) != 0)
414 return 1;
415 return ocsp_verify_signer(signer, 0, store, flags,
416 (flags & OCSP_NOCHAIN) != 0 ?
417 NULL : req->optionalSignature->certs, NULL) > 0;
418 /* using '> 0' here to avoid breaking backward compatibility returning -1 */
419 }
420
ocsp_req_find_signer(X509 ** psigner,OCSP_REQUEST * req,const X509_NAME * nm,STACK_OF (X509)* certs,unsigned long flags)421 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req,
422 const X509_NAME *nm, STACK_OF(X509) *certs,
423 unsigned long flags)
424 {
425 X509 *signer;
426
427 if ((flags & OCSP_NOINTERN) == 0) {
428 signer = X509_find_by_subject(req->optionalSignature->certs, nm);
429 if (signer != NULL) {
430 *psigner = signer;
431 return 1;
432 }
433 }
434
435 if ((signer = X509_find_by_subject(certs, nm)) != NULL) {
436 *psigner = signer;
437 return 2;
438 }
439 return 0;
440 }
441