summaryrefslogtreecommitdiffstats
path: root/crypto/ocsp/ocsp_vfy.c
blob: 214b4020fee79aa9cbca456a48097ac263073551 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
/* ocsp_vfy.c */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project 2000.
 */
/* ====================================================================
 * Copyright (c) 2000-2004 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <openssl/ocsp.h>
#include <openssl/err.h>
#include <string.h>

static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
				X509_STORE *st, unsigned long flags);
static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags);
static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret);
static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid, STACK_OF(OCSP_SINGLERESP) *sresp);
static int ocsp_check_delegated(X509 *x, int flags);
static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs,
				X509_STORE *st, unsigned long flags);

/* Verify a basic response message */

int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
				X509_STORE *st, unsigned long flags)
	{
	X509 *signer, *x;
	STACK_OF(X509) *chain = NULL;
	STACK_OF(X509) *tmpchain = NULL;
	X509_STORE *tmpstore = NULL;
	X509_STORE_CTX ctx;
	int i, ret;
	ret = ocsp_find_signer(&signer, bs, certs, st, flags);
	if (!ret)
		{
		OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
		goto end;
		}
	if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
		chain = certs;
	if (!(flags & OCSP_NOSIGS))
		{
		EVP_PKEY *skey;
		skey = X509_get_pubkey(signer);
		ret = OCSP_BASICRESP_verify(bs, skey, 0);
		EVP_PKEY_free(skey);
		if(ret <= 0)
			{
			OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNATURE_FAILURE);
			goto end;
			}
		}
	if (!(flags & OCSP_NOVERIFY))
		{
		int init_res;

		/* If we trust the signer, we don't need to build a chain.
		 * (If the signer is a root certificate, X509_verify_cert()
		 * would fail anyway!)
		 */
		if (chain == certs) goto verified_chain;

		/* If we trust some "other" certificates, mark them as
		 * explicitly trusted (because some of them might be
		 * Intermediate CA Certificates), put them in a store and
		 * attempt to build a trusted chain.
		 */
		if ((flags & OCSP_TRUSTOTHER) && (certs != NULL))
			{
			ASN1_OBJECT *objtmp = OBJ_nid2obj(NID_OCSP_sign);
			tmpstore = X509_STORE_new();
			if (!tmpstore)
				{
				ret = -1;
				OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, ERR_R_MALLOC_FAILURE);
				goto end;
				}
			for (i = 0; i < sk_X509_num(certs); i++)
				{
				X509 *xother = sk_X509_value(certs, i);
				X509_add1_trust_object(xother, objtmp);
				if (!X509_STORE_add_cert(tmpstore, xother))
					{
					ret = -1;
					goto end;
					}
				}

			init_res = X509_STORE_CTX_init(&ctx, tmpstore, signer, NULL);
			if (!init_res)
				{
				ret = -1;
				OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,ERR_R_X509_LIB);
				goto end;
				}
			X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
			ret = X509_verify_cert(&ctx);
			if (ret == 1)
				{
				chain = tmpchain = X509_STORE_CTX_get1_chain(&ctx);
				X509_STORE_CTX_cleanup(&ctx);
				goto verified_chain;
				}
			X509_STORE_CTX_cleanup(&ctx);
			}

		/* Attempt to build a chain up to a Root Certificate in the
		 * trust store provided by the caller.
		 */
		if(flags & OCSP_NOCHAIN)
			init_res = X509_STORE_CTX_init(&ctx, st, signer, NULL);
		else
			init_res = X509_STORE_CTX_init(&ctx, st, signer, bs->certs);
		if(!init_res)
			{
			ret = -1;
			OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,ERR_R_X509_LIB);
			goto end;
			}

		X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
		ret = X509_verify_cert(&ctx);
		chain = tmpchain = X509_STORE_CTX_get1_chain(&ctx);
		X509_STORE_CTX_cleanup(&ctx);
		if (ret <= 0)
			{
			i = X509_STORE_CTX_get_error(&ctx);	
			OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
			ERR_add_error_data(2, "Verify error:",
					X509_verify_cert_error_string(i));
			goto end;
			}

	verified_chain:
		if(flags & OCSP_NOCHECKS)
			{
			ret = 1;
			goto end;
			}
		/* At this point we have a valid certificate chain
		 * need to verify it against the OCSP issuer criteria.
		 */
		ret = ocsp_check_issuer(bs, chain, flags);

		/* If fatal error or valid match then finish */
		if (ret != 0) goto end;

		/* Easy case: explicitly trusted. Get root CA and
		 * check for explicit trust
		 */
		if(flags & OCSP_NOEXPLICIT) goto end;

		x = sk_X509_value(chain, sk_X509_num(chain) - 1);
		if(X509_check_trust(x, NID_OCSP_sign, 0) != X509_TRUST_TRUSTED)
			{
			OCSPerr(OCSP_F_OCSP_BASIC_VERIFY,OCSP_R_ROOT_CA_NOT_TRUSTED);
			goto end;
			}
		ret = 1;
		}



	end:
	if(tmpchain) sk_X509_pop_free(tmpchain, X509_free);
	if(tmpstore) X509_STORE_free(tmpstore);
	return ret;
	}


static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
				X509_STORE *st, unsigned long flags)
	{
	X509 *signer;
	OCSP_RESPID *rid = bs->tbsResponseData->responderId;
	if ((signer = ocsp_find_signer_sk(certs, rid)))
		{
		*psigner = signer;
		return 2;
		}
	if(!(flags & OCSP_NOINTERN) &&
	    (signer = ocsp_find_signer_sk(bs->certs, rid)))
		{
		*psigner = signer;
		return 1;
		}
	/* Maybe lookup from store if by subject name */

	*psigner = NULL;
	return 0;
	}


static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
	{
	int i;
	unsigned char tmphash[SHA_DIGEST_LENGTH], *keyhash;
	X509 *x;

	/* Easy if lookup by name */
	if (id->type == V_OCSP_RESPID_NAME)
		return X509_find_by_subject(certs, id->value.byName);

	/* Lookup by key hash */

	/* If key hash isn't SHA1 length then forget it */
	if (id->value.byKey->length != SHA_DIGEST_LENGTH) return NULL;
	keyhash = id->value.byKey->data;
	/* Calculate hash of each key and compare */
	for (i = 0; i < sk_X509_num(certs); i++)
		{
		x = sk_X509_value(certs, i);
		X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
		if(!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
			return x;
		}
	return NULL;
	}


static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags)
	{
	STACK_OF(OCSP_SINGLERESP) *sresp;
	X509 *signer, *sca;
	OCSP_CERTID *caid = NULL;
	int i;
	sresp = bs->tbsResponseData->responses;

	if (sk_X509_num(chain) <= 0)
		{
		OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
		return -1;
		}

	/* See if the issuer IDs match. */
	i = ocsp_check_ids(sresp, &caid);

	/* If ID mismatch or other error then return */
	if (i <= 0) return i;

	signer = sk_X509_value(chain, 0);
	/* Check to see if OCSP responder CA matches request CA */
	if (sk_X509_num(chain) > 1)
		{
		sca = sk_X509_value(chain, 1);
		i = ocsp_match_issuerid(sca, caid, sresp);
		if (i < 0) return i;
		if (i)
			{
			/* We have a match, if extensions OK then success */
			if (ocsp_check_delegated(signer, flags)) return 1;
			return 0;
			}
		}

	/* Otherwise check if OCSP request signed directly by request CA */
	return ocsp_match_issuerid(signer, caid, sresp);
	}


/* Check the issuer certificate IDs for equality. If there is a mismatch with the same
 * algorithm then there's no point trying to match any certificates against the issuer.
 * If the issuer IDs all match then we just need to check equality against one of them.
 */
	
static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
	{
	OCSP_CERTID *tmpid, *cid;
	int i, idcount;

	idcount = sk_OCSP_SINGLERESP_num(sresp);
	if (idcount <= 0)
		{
		OCSPerr(OCSP_F_OCSP_CHECK_IDS, OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
		return -1;
		}

	cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;

	*ret = NULL;

	for (i = 1; i < idcount; i++)
		{
		tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
		/* Check to see if IDs match */
		if (OCSP_id_issuer_cmp(cid, tmpid))
			{
			/* If algoritm mismatch let caller deal with it */
			if (OBJ_cmp(tmpid->hashAlgorithm->algorithm,
					cid->hashAlgorithm->algorithm))
					return 2;
			/* Else mismatch */
			return 0;
			}
		}

	/* All IDs match: only need to check one ID */
	*ret = cid;
	return 1;
	}


static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
			STACK_OF(OCSP_SINGLERESP) *sresp)
	{
	/* If only one ID to match then do it */
	if(cid)
		{
		const EVP_MD *dgst;
		X509_NAME *iname;
		int mdlen;
		unsigned char md[EVP_MAX_MD_SIZE];
		if (!(dgst = EVP_get_digestbyobj(cid->hashAlgorithm->algorithm)))
			{
			OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID, OCSP_R_UNKNOWN_MESSAGE_DIGEST);
			return -1;
			}

		mdlen = EVP_MD_size(dgst);
		if (mdlen < 0)
		    return -1;
		if ((cid->issuerNameHash->length != mdlen) ||
		   (cid->issuerKeyHash->length != mdlen))
			return 0;
		iname = X509_get_subject_name(cert);
		if (!X509_NAME_digest(iname, dgst, md, NULL))
			return -1;
		if (memcmp(md, cid->issuerNameHash->data, mdlen))
			return 0;
		X509_pubkey_digest(cert, dgst, md, NULL);
		if (memcmp(md, cid->issuerKeyHash->data, mdlen))
			return 0;

		return 1;

		}
	else
		{
		/* We have to match the whole lot */
		int i, ret;
		OCSP_CERTID *tmpid;
		for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++)
			{
			tmpid = sk_OCSP_SINGLERESP_value(sresp, i)->certId;
			ret = ocsp_match_issuerid(cert, tmpid, NULL);
			if (ret <= 0) return ret;
			}
		return 1;
		}
			
	}

static int ocsp_check_delegated(X509 *x, int flags)
	{
	X509_check_purpose(x, -1, 0);
	if ((x->ex_flags & EXFLAG_XKUSAGE) &&
	    (x->ex_xkusage & XKU_OCSP_SIGN))
		return 1;
	OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
	return 0;
	}

/* Verify an OCSP request. This is fortunately much easier than OCSP
 * response verify. Just find the signers certificate and verify it
 * against a given trust value.
 */

int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs, X509_STORE *store, unsigned long flags)
        {
	X509 *signer;
	X509_NAME *nm;
	GENERAL_NAME *gen;
	int ret;
	X509_STORE_CTX ctx;
	if (!req->optionalSignature) 
		{
		OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_REQUEST_NOT_SIGNED);
		return 0;
		}
	gen = req->tbsRequest->requestorName;
	if (!gen || gen->type != GEN_DIRNAME)
		{
		OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_UNSUPPORTED_REQUESTORNAME_TYPE);
		return 0;
		}
	nm = gen->d.directoryName;
	ret = ocsp_req_find_signer(&signer, req, nm, certs, store, flags);
	if (ret <= 0)
		{
		OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
		return 0;
		}
	if ((ret == 2) && (flags & OCSP_TRUSTOTHER))
		flags |= OCSP_NOVERIFY;
	if (!(flags & OCSP_NOSIGS))
		{
		EVP_PKEY *skey;
		skey = X509_get_pubkey(signer);
		ret = OCSP_REQUEST_verify(req, skey);
		EVP_PKEY_free(skey);
		if(ret <= 0)
			{
			OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY, OCSP_R_SIGNATURE_FAILURE);
			return 0;
			}
		}
	if (!(flags & OCSP_NOVERIFY))
		{
		int init_res;
		if(flags & OCSP_NOCHAIN)
			init_res = X509_STORE_CTX_init(&ctx, store, signer, NULL);
		else
			init_res = X509_STORE_CTX_init(&ctx, store, signer,
					req->optionalSignature->certs);
		if(!init_res)
			{
			OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,ERR_R_X509_LIB);
			return 0;
			}

		X509_STORE_CTX_set_purpose(&ctx, X509_PURPOSE_OCSP_HELPER);
		X509_STORE_CTX_set_trust(&ctx, X509_TRUST_OCSP_REQUEST);
		ret = X509_verify_cert(&ctx);
		X509_STORE_CTX_cleanup(&ctx);
                if (ret <= 0)
			{
			ret = X509_STORE_CTX_get_error(&ctx);	
			OCSPerr(OCSP_F_OCSP_REQUEST_VERIFY,OCSP_R_CERTIFICATE_VERIFY_ERROR);
			ERR_add_error_data(2, "Verify error:",
					X509_verify_cert_error_string(ret));
                        return 0;
                	}
		}
	return 1;
        }

static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req, X509_NAME *nm, STACK_OF(X509) *certs,
				X509_STORE *st, unsigned long flags)
	{
	X509 *signer;
	if(!(flags & OCSP_NOINTERN))
		{
		signer = X509_find_by_subject(req->optionalSignature->certs, nm);
		*psigner = signer;
		return 1;
		}

	signer = X509_find_by_subject(certs, nm);
	if (signer)
		{
		*psigner = signer;
		return 2;
		}
	return 0;
	}