1 /* ocsp_vfy.c */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3 * project 2000.
4 */
5 /* ====================================================================
6 * Copyright (c) 2000-2004 The OpenSSL Project. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24 *
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * licensing@OpenSSL.org.
29 *
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
33 *
34 * 6. Redistributions of any form whatsoever must retain the following
35 * acknowledgment:
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
52 *
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
56 *
57 */
58
59 #include <openssl/ocsp.h>
60 #include <openssl/err.h>
61 #include <string.h>
62
63 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
64 X509_STORE *st, unsigned long flags);
65 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
66 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags);
67 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret);
68 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid, STACK_OF(OCSP_SINGLERESP) *sresp);
69 static int ocsp_check_delegated(X509 *x, int flags);
70 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs,
71 X509_STORE *st, unsigned long flags);
72
73 /* Verify a basic response message */
74
75 int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
76 X509_STORE *st, unsigned long flags)
77 {
78 X509 *signer, *x;
79 STACK_OF(X509) *chain = NULL;
80 X509_STORE_CTX ctx;
81 int i, ret = 0;
82 ret = ocsp_find_signer(&signer, bs, certs, st, flags);
83 if (!ret)
84 {
85 OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
86 goto end;
87 }
88 if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
89 flags |= OCSP_NOVERIFY;
90 if (!(flags & OCSP_NOSIGS))
91 {
92 EVP_PKEY *skey;
93 skey = X509_get_pubkey(signer);
94 if (skey)
95 {
96 ret = OCSP_BASICRESP_verify(bs, skey, 0);
97 EVP_PKEY_free(skey);
98 }
99 if(!skey || ret <= 0)
100 {
101 OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
102 goto end;
103 }
104 }
105 if (!(flags & OCSP_NOVERIFY))
106 {
107 int init_res;
108 if(flags & OCSP_NOCHAIN)
109 init_res = X509_STORE_CTX_init(&ctx, st, signer, NULL);
110 else
111 init_res = X509_STORE_CTX_init(&ctx, st, signer, bs->certs);
112 if(!init_res)
113 {
114 ret = -1;
115 OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,ERR_R_X509_LIB);
116 goto end;
117 }
118
119 X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
120 ret = X509_verify_cert(&ctx);
121 chain = X509_STORE_CTX_get1_chain(&ctx);
122 X509_STORE_CTX_cleanup(&ctx);
123 if (ret <= 0)
124 {
125 i = X509_STORE_CTX_get_error(&ctx);
126 OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
127 ERR_add_error_data(2, "Verify error:",
128 X509_verify_cert_error_string(i));
129 goto end;
130 }
131 if(flags & OCSP_NOCHECKS)
132 {
133 ret = 1;
134 goto end;
135 }
136 /* At this point we have a valid certificate chain
137 * need to verify it against the OCSP issuer criteria.
138 */
139 ret = ocsp_check_issuer(bs, chain, flags);
140
141 /* If fatal error or valid match then finish */
142 if (ret != 0) goto end;
143
144 /* Easy case: explicitly trusted. Get root CA and
145 * check for explicit trust
146 */
147 if(flags & OCSP_NOEXPLICIT) goto end;
148
149 x = sk_X509_value(chain, sk_X509_num(chain) - 1);
150 if(X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED)
151 {
152 OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_ROOT_CA_NOT_TRUSTED);
153 goto end;
154 }
155 ret = 1;
156 }
157
158
159
160 end:
161 if(chain) sk_X509_pop_free(chain, X509_free);
162 return ret;
163 }
164
165
166 static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
167 X509_STORE *st, unsigned long flags)
168 {
169 X509 *signer;
170 OCSP_RESPID *rid = bs->tbsResponseData->responderId;
171 if ((signer = ocsp_find_signer_sk(certs, rid)))
172 {
173 *psigner = signer;
174 return 2;
175 }
176 if(!(flags & OCSP_NOINTERN) &&
177 (signer = ocsp_find_signer_sk(bs->certs, rid)))
178 {
179 *psigner = signer;
180 return 1;
181 }
182 /* Maybe lookup from store if by subject name */
183
184 *psigner = NULL;
185 return 0;
186 }
187
188
189 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
190 {
191 int i;
192 unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
193 X509 *x;
194
195 /* Easy if lookup by name */
196 if (id->type == V_OCSP_RESPID_NAME)
197 return X509_find_by_subject(certs, id->value.byName);
198
199 /* Lookup by key hash */
200
201 /* If key hash isn't SHA1 length then forget it */
202 if (id->value.byKey->length != SHA_DIGEST_LENGTH) return NULL;
203 keyhash = id->value.byKey->data;
204 /* Calculate hash of each key and compare */
205 for (i = 0; i < sk_X509_num(certs); i++)
206 {
207 x = sk_X509_value(certs, i);
208 X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
209 if(!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
210 return x;
211 }
212 return NULL;
213 }
214
215
216 static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags)
217 {
218 STACK_OF(OCSP_SINGLERESP) *sresp;
219 X509 *signer, *sca;
220 OCSP_CERTID *caid = NULL;
221 int i;
222 sresp = bs->tbsResponseData->responses;
223
224 if (sk_X509_num(chain) <= 0)
225 {
226 OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
227 return -1;
228 }
229
230 /* See if the issuer IDs match. */
231 i = ocsp_check_ids(sresp, &caid);
232
233 /* If ID mismatch or other error then return */
234 if (i <= 0) return i;
235
236 signer = sk_X509_value(chain, 0);
237 /* Check to see if OCSP responder CA matches request CA */
238 if (sk_X509_num(chain) > 1)
239 {
240 sca = sk_X509_value(chain, 1);
241 i = ocsp_match_issuerid(sca, caid, sresp);
242 if (i < 0) return i;
243 if (i)
244 {
245 /* We have a match, if extensions OK then success */
246 if (ocsp_check_delegated(signer, flags)) return 1;
247 return 0;
248 }
249 }
250
251 /* Otherwise check if OCSP request signed directly by request CA */
252 return ocsp_match_issuerid(signer, caid, sresp);
253 }
254
255
256 /* Check the issuer certificate IDs for equality. If there is a mismatch with the same
257 * algorithm then there's no point trying to match any certificates against the issuer.
258 * If the issuer IDs all match then we just need to check equality against one of them.
259 */
260
261 static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
262 {
263 OCSP_CERTID *tmpid, *cid;
264 int i, idcount;
265
266 idcount = sk_OCSP_SINGLERESP_num(sresp);
267 if (idcount <= 0)
268 {
269 OCSPerr(OCSP_F_OCSP_CHECK_IDS, OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
270 return -1;
271 }
272
273 cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
274
275 *ret = NULL;
276
277 for (i = 1; i < idcount; i++)
278 {
279 tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
280 /* Check to see if IDs match */
281 if (OCSP_id_issuer_cmp(cid, tmpid))
282 {
283 /* If algoritm mismatch let caller deal with it */
284 if (OBJ_cmp(tmpid->hashAlgorithm->algorithm,
285 cid->hashAlgorithm->algorithm))
286 return 2;
287 /* Else mismatch */
288 return 0;
289 }
290 }
291
292 /* All IDs match: only need to check one ID */
293 *ret = cid;
294 return 1;
295 }
296
297
298 static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
299 STACK_OF(OCSP_SINGLERESP) *sresp)
300 {
301 /* If only one ID to match then do it */
302 if(cid)
303 {
304 const EVP_MD *dgst;
305 X509_NAME *iname;
306 int mdlen;
307 unsigned char md[EVP_MAX_MD_SIZE];
308 if (!(dgst = EVP_get_digestbyobj(cid->hashAlgorithm->algorithm)))
309 {
310 OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID, OCSP_R_UNKNOWN_MESSAGE_DIGEST);
311 return -1;
312 }
313
314 mdlen = EVP_MD_size(dgst);
315 if (mdlen < 0)
316 return -1;
317 if ((cid->issuerNameHash->length != mdlen) ||
318 (cid->issuerKeyHash->length != mdlen))
319 return 0;
320 iname = X509_get_subject_name(cert);
321 if (!X509_NAME_digest(iname, dgst, md, NULL))
322 return -1;
323 if (memcmp(md, cid->issuerNameHash->data, mdlen))
324 return 0;
325 X509_pubkey_digest(cert, dgst, md, NULL);
326 if (memcmp(md, cid->issuerKeyHash->data, mdlen))
327 return 0;
328
329 return 1;
330
331 }
332 else
333 {
334 /* We have to match the whole lot */
335 int i, ret;
336 OCSP_CERTID *tmpid;
337 for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++)
338 {
339 tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
340 ret = ocsp_match_issuerid(cert, tmpid, NULL);
341 if (ret <= 0) return ret;
342 }
343 return 1;
344 }
345
346 }
347
348 static int ocsp_check_delegated(X509 *x, int flags)
349 {
350 X509_check_purpose(x, -1, 0);
351 if ((x->ex_flags & EXFLAG_XKUSAGE) &&
352 (x->ex_xkusage & XKU_OCSP_SIGN))
353 return 1;
354 OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
355 return 0;
356 }
357
358 /* Verify an OCSP request. This is fortunately much easier than OCSP
359 * response verify. Just find the signers certificate and verify it
360 * against a given trust value.
361 */
362
363 int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs, X509_STORE *store, unsigned long flags)
364 {
365 X509 *signer;
366 X509_NAME *nm;
367 GENERAL_NAME *gen;
368 int ret;
369 X509_STORE_CTX ctx;
370 if (!req->optionalSignature)
371 {
372 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
373 return 0;
374 }
375 gen = req->tbsRequest->requestorName;
376 if (!gen || gen->type != GEN_DIRNAME)
377 {
378 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
379 return 0;
380 }
381 nm = gen->d.directoryName;
382 ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags);
383 if (ret <= 0)
384 {
385 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
386 return 0;
387 }
388 if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
389 flags |= OCSP_NOVERIFY;
390 if (!(flags & OCSP_NOSIGS))
391 {
392 EVP_PKEY *skey;
393 skey = X509_get_pubkey(signer);
394 ret = OCSP_REQUEST_verify(req, skey);
395 EVP_PKEY_free(skey);
396 if(ret <= 0)
397 {
398 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
399 return 0;
400 }
401 }
402 if (!(flags & OCSP_NOVERIFY))
403 {
404 int init_res;
405 if(flags & OCSP_NOCHAIN)
406 init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL);
407 else
408 init_res = X509_STORE_CTX_init(&ctx, store, signer,
409 req->optionalSignature->certs);
410 if(!init_res)
411 {
412 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,ERR_R_X509_LIB);
413 return 0;
414 }
415
416 X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
417 X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST);
418 ret = X509_verify_cert(&ctx);
419 X509_STORE_CTX_cleanup(&ctx);
420 if (ret <= 0)
421 {
422 ret = X509_STORE_CTX_get_error(&ctx);
423 OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
424 ERR_add_error_data(2, "Verify error:",
425 X509_verify_cert_error_string(ret));
426 return 0;
427 }
428 }
429 return 1;
430 }
431
432 static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs,
433 X509_STORE *st, unsigned long flags)
434 {
435 X509 *signer;
436 if(!(flags & OCSP_NOINTERN))
437 {
438 signer = X509_find_by_subject(req->optionalSignature->certs, nm);
439 *psigner = signer;
440 return 1;
441 }
442
443 signer = X509_find_by_subject(certs, nm);
444 if (signer)
445 {
446 *psigner = signer;
447 return 2;
448 }
449 return 0;
450 }