v3_purp.c@ 91772

Last change on this file since 91772 was 91772, checked in by vboxsync, 3 years ago
openssl-1.1.1l: Applied and adjusted our OpenSSL changes to 1.1.1l. bugref:10126
File size: 29.8 KB

Line
1	/*
2	* Copyright 1999-2021 The OpenSSL Project Authors. All Rights Reserved.
3	*
4	* Licensed under the OpenSSL license (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 "../x509/x509_local.h" /* for x509_signing_allowed() */
17	#include "internal/tsan_assist.h"
18
19	static void x509v3_cache_extensions(X509 *x);
20
21	static int check_ssl_ca(const X509 *x);
22	static int check_purpose_ssl_client(const X509_PURPOSE xp, const X509 x,
23	int ca);
24	static int check_purpose_ssl_server(const X509_PURPOSE xp, const X509 x,
25	int ca);
26	static int check_purpose_ns_ssl_server(const X509_PURPOSE xp, const X509 x,
27	int ca);
28	static int purpose_smime(const X509 *x, int ca);
29	static int check_purpose_smime_sign(const X509_PURPOSE xp, const X509 x,
30	int ca);
31	static int check_purpose_smime_encrypt(const X509_PURPOSE xp, const X509 x,
32	int ca);
33	static int check_purpose_crl_sign(const X509_PURPOSE xp, const X509 x,
34	int ca);
35	static int check_purpose_timestamp_sign(const X509_PURPOSE xp, const X509 x,
36	int ca);
37	static int no_check(const X509_PURPOSE xp, const X509 x, int ca);
38	static int ocsp_helper(const X509_PURPOSE xp, const X509 x, int ca);
39
40	static int xp_cmp(const X509_PURPOSE const a, const X509_PURPOSE const b);
41	static void xptable_free(X509_PURPOSE *p);
42
43	static X509_PURPOSE xstandard[] = {
44	{X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0,
45	check_purpose_ssl_client, "SSL client", "sslclient", NULL},
46	{X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
47	check_purpose_ssl_server, "SSL server", "sslserver", NULL},
48	{X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
49	check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
50	{X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign,
51	"S/MIME signing", "smimesign", NULL},
52	{X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0,
53	check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
54	{X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign,
55	"CRL signing", "crlsign", NULL},
56	{X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any",
57	NULL},
58	{X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper,
59	"OCSP helper", "ocsphelper", NULL},
60	{X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0,
61	check_purpose_timestamp_sign, "Time Stamp signing", "timestampsign",
62	NULL},
63	};
64
65	#define X509_PURPOSE_COUNT OSSL_NELEM(xstandard)
66
67	static STACK_OF(X509_PURPOSE) *xptable = NULL;
68
69	static int xp_cmp(const X509_PURPOSE const a, const X509_PURPOSE const b)
70	{
71	return (a)->purpose - (b)->purpose;
72	}
73
74	/*
75	* As much as I'd like to make X509_check_purpose use a "const" X509* I
76	* really can't because it does recalculate hashes and do other non-const
77	* things.
78	*/
79	int X509_check_purpose(X509 *x, int id, int ca)
80	{
81	int idx;
82	const X509_PURPOSE *pt;
83
84	x509v3_cache_extensions(x);
85	if (x->ex_flags & EXFLAG_INVALID)
86	return -1;
87
88	/* Return if side-effect only call */
89	if (id == -1)
90	return 1;
91	idx = X509_PURPOSE_get_by_id(id);
92	if (idx == -1)
93	return -1;
94	pt = X509_PURPOSE_get0(idx);
95	return pt->check_purpose(pt, x, ca);
96	}
97
98	int X509_PURPOSE_set(int *p, int purpose)
99	{
100	if (X509_PURPOSE_get_by_id(purpose) == -1) {
101	X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE);
102	return 0;
103	}
104	*p = purpose;
105	return 1;
106	}
107
108	int X509_PURPOSE_get_count(void)
109	{
110	if (!xptable)
111	return X509_PURPOSE_COUNT;
112	return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
113	}
114
115	X509_PURPOSE *X509_PURPOSE_get0(int idx)
116	{
117	if (idx < 0)
118	return NULL;
119	if (idx < (int)X509_PURPOSE_COUNT)
120	return xstandard + idx;
121	return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
122	}
123
124	int X509_PURPOSE_get_by_sname(const char *sname)
125	{
126	int i;
127	X509_PURPOSE *xptmp;
128	for (i = 0; i < X509_PURPOSE_get_count(); i++) {
129	xptmp = X509_PURPOSE_get0(i);
130	if (strcmp(xptmp->sname, sname) == 0)
131	return i;
132	}
133	return -1;
134	}
135
136	int X509_PURPOSE_get_by_id(int purpose)
137	{
138	X509_PURPOSE tmp;
139	int idx;
140
141	if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
142	return purpose - X509_PURPOSE_MIN;
143	if (xptable == NULL)
144	return -1;
145	tmp.purpose = purpose;
146	idx = sk_X509_PURPOSE_find(xptable, &tmp);
147	if (idx < 0)
148	return -1;
149	return idx + X509_PURPOSE_COUNT;
150	}
151
152	int X509_PURPOSE_add(int id, int trust, int flags,
153	int (ck) (const X509_PURPOSE , const X509 *, int),
154	const char name, const char sname, void *arg)
155	{
156	int idx;
157	X509_PURPOSE *ptmp;
158	/*
159	* This is set according to what we change: application can't set it
160	*/
161	flags &= ~X509_PURPOSE_DYNAMIC;
162	/* This will always be set for application modified trust entries */
163	flags \|= X509_PURPOSE_DYNAMIC_NAME;
164	/* Get existing entry if any */
165	idx = X509_PURPOSE_get_by_id(id);
166	/* Need a new entry */
167	if (idx == -1) {
168	if ((ptmp = OPENSSL_malloc(sizeof(*ptmp))) == NULL) {
169	X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
170	return 0;
171	}
172	ptmp->flags = X509_PURPOSE_DYNAMIC;
173	} else
174	ptmp = X509_PURPOSE_get0(idx);
175
176	/* OPENSSL_free existing name if dynamic */
177	if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
178	OPENSSL_free(ptmp->name);
179	OPENSSL_free(ptmp->sname);
180	}
181	/* dup supplied name */
182	ptmp->name = OPENSSL_strdup(name);
183	ptmp->sname = OPENSSL_strdup(sname);
184	if (!ptmp->name \|\| !ptmp->sname) {
185	X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
186	goto err;
187	}
188	/* Keep the dynamic flag of existing entry */
189	ptmp->flags &= X509_PURPOSE_DYNAMIC;
190	/* Set all other flags */
191	ptmp->flags \|= flags;
192
193	ptmp->purpose = id;
194	ptmp->trust = trust;
195	ptmp->check_purpose = ck;
196	ptmp->usr_data = arg;
197
198	/* If its a new entry manage the dynamic table */
199	if (idx == -1) {
200	if (xptable == NULL
201	&& (xptable = sk_X509_PURPOSE_new(xp_cmp)) == NULL) {
202	X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
203	goto err;
204	}
205	if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
206	X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
207	goto err;
208	}
209	}
210	return 1;
211	err:
212	if (idx == -1) {
213	OPENSSL_free(ptmp->name);
214	OPENSSL_free(ptmp->sname);
215	OPENSSL_free(ptmp);
216	}
217	return 0;
218	}
219
220	static void xptable_free(X509_PURPOSE *p)
221	{
222	if (!p)
223	return;
224	if (p->flags & X509_PURPOSE_DYNAMIC) {
225	if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
226	OPENSSL_free(p->name);
227	OPENSSL_free(p->sname);
228	}
229	OPENSSL_free(p);
230	}
231	}
232
233	void X509_PURPOSE_cleanup(void)
234	{
235	sk_X509_PURPOSE_pop_free(xptable, xptable_free);
236	xptable = NULL;
237	}
238
239	int X509_PURPOSE_get_id(const X509_PURPOSE *xp)
240	{
241	return xp->purpose;
242	}
243
244	char X509_PURPOSE_get0_name(const X509_PURPOSE xp)
245	{
246	return xp->name;
247	}
248
249	char X509_PURPOSE_get0_sname(const X509_PURPOSE xp)
250	{
251	return xp->sname;
252	}
253
254	int X509_PURPOSE_get_trust(const X509_PURPOSE *xp)
255	{
256	return xp->trust;
257	}
258
259	static int nid_cmp(const int a, const int b)
260	{
261	return a - b;
262	}
263
264	DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid);
265	IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid);
266
267	int X509_supported_extension(X509_EXTENSION *ex)
268	{
269	/*
270	* This table is a list of the NIDs of supported extensions: that is
271	* those which are used by the verify process. If an extension is
272	* critical and doesn't appear in this list then the verify process will
273	* normally reject the certificate. The list must be kept in numerical
274	* order because it will be searched using bsearch.
275	*/
276
277	static const int supported_nids[] = {
278	NID_netscape_cert_type, /* 71 */
279	NID_key_usage, /* 83 */
280	NID_subject_alt_name, /* 85 */
281	NID_basic_constraints, /* 87 */
282	NID_certificate_policies, /* 89 */
283	NID_crl_distribution_points, /* 103 */
284	NID_ext_key_usage, /* 126 */
285	#ifndef OPENSSL_NO_RFC3779
286	NID_sbgp_ipAddrBlock, /* 290 */
287	NID_sbgp_autonomousSysNum, /* 291 */
288	#endif
289	NID_policy_constraints, /* 401 */
290	NID_proxyCertInfo, /* 663 */
291	NID_name_constraints, /* 666 */
292	NID_policy_mappings, /* 747 */
293	NID_inhibit_any_policy /* 748 */
294	};
295
296	int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
297
298	if (ex_nid == NID_undef)
299	return 0;
300
301	if (OBJ_bsearch_nid(&ex_nid, supported_nids, OSSL_NELEM(supported_nids)))
302	return 1;
303	return 0;
304	}
305
306	static int setup_dp(X509 x, DIST_POINT dp)
307	{
308	X509_NAME *iname = NULL;
309	int i;
310
311	if (dp->reasons) {
312	if (dp->reasons->length > 0)
313	dp->dp_reasons = dp->reasons->data[0];
314	if (dp->reasons->length > 1)
315	dp->dp_reasons \|= (dp->reasons->data[1] << 8);
316	dp->dp_reasons &= CRLDP_ALL_REASONS;
317	} else
318	dp->dp_reasons = CRLDP_ALL_REASONS;
319	if (!dp->distpoint \|\| (dp->distpoint->type != 1))
320	return 1;
321	for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) {
322	GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
323	if (gen->type == GEN_DIRNAME) {
324	iname = gen->d.directoryName;
325	break;
326	}
327	}
328	if (!iname)
329	iname = X509_get_issuer_name(x);
330
331	return DIST_POINT_set_dpname(dp->distpoint, iname);
332	}
333
334	static int setup_crldp(X509 *x)
335	{
336	int i;
337
338	x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, &i, NULL);
339	if (x->crldp == NULL && i != -1)
340	return 0;
341	for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) {
342	if (!setup_dp(x, sk_DIST_POINT_value(x->crldp, i)))
343	return 0;
344	}
345	return 1;
346	}
347
348	/* Check that issuer public key algorithm matches subject signature algorithm */
349	static int check_sig_alg_match(const EVP_PKEY pkey, const X509 subject)
350	{
351	int pkey_sig_nid, subj_sig_nid;
352
353	if (pkey == NULL)
354	return X509_V_ERR_NO_ISSUER_PUBLIC_KEY;
355	if (OBJ_find_sigid_algs(EVP_PKEY_base_id(pkey),
356	NULL, &pkey_sig_nid) == 0)
357	pkey_sig_nid = EVP_PKEY_base_id(pkey);
358	if (OBJ_find_sigid_algs(OBJ_obj2nid(subject->cert_info.signature.algorithm),
359	NULL, &subj_sig_nid) == 0)
360	return X509_V_ERR_UNSUPPORTED_SIGNATURE_ALGORITHM;
361	if (pkey_sig_nid != EVP_PKEY_type(subj_sig_nid))
362	return X509_V_ERR_SIGNATURE_ALGORITHM_MISMATCH;
363	return X509_V_OK;
364	}
365
366	#define V1_ROOT (EXFLAG_V1\|EXFLAG_SS)
367	#define ku_reject(x, usage) \
368	(((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
369	#define xku_reject(x, usage) \
370	(((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
371	#define ns_reject(x, usage) \
372	(((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
373
374	static void x509v3_cache_extensions(X509 *x)
375	{
376	BASIC_CONSTRAINTS *bs;
377	PROXY_CERT_INFO_EXTENSION *pci;
378	ASN1_BIT_STRING *usage;
379	ASN1_BIT_STRING *ns;
380	EXTENDED_KEY_USAGE *extusage;
381	X509_EXTENSION *ex;
382	int i;
383
384	#ifdef tsan_ld_acq
385	/* fast lock-free check, see end of the function for details. */
386	if (tsan_ld_acq((TSAN_QUALIFIER int *)&x->ex_cached))
387	return;
388	#endif
389
390	CRYPTO_THREAD_write_lock(x->lock);
391	if (x->ex_flags & EXFLAG_SET) {
392	CRYPTO_THREAD_unlock(x->lock);
393	return;
394	}
395
396	if (!X509_digest(x, EVP_sha1(), x->sha1_hash, NULL))
397	x->ex_flags \|= (EXFLAG_NO_FINGERPRINT \| EXFLAG_INVALID);
398
399	/* V1 should mean no extensions ... */
400	if (!X509_get_version(x))
401	x->ex_flags \|= EXFLAG_V1;
402	/* Handle basic constraints */
403	if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, &i, NULL))) {
404	if (bs->ca)
405	x->ex_flags \|= EXFLAG_CA;
406	if (bs->pathlen) {
407	if (bs->pathlen->type == V_ASN1_NEG_INTEGER) {
408	x->ex_flags \|= EXFLAG_INVALID;
409	x->ex_pathlen = 0;
410	} else {
411	x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
412	if (!bs->ca && x->ex_pathlen != 0) {
413	x->ex_flags \|= EXFLAG_INVALID;
414	x->ex_pathlen = 0;
415	}
416	}
417	} else
418	x->ex_pathlen = -1;
419	BASIC_CONSTRAINTS_free(bs);
420	x->ex_flags \|= EXFLAG_BCONS;
421	} else if (i != -1) {
422	x->ex_flags \|= EXFLAG_INVALID;
423	}
424	/* Handle proxy certificates */
425	if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, &i, NULL))) {
426	if (x->ex_flags & EXFLAG_CA
427	\|\| X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
428	\|\| X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
429	x->ex_flags \|= EXFLAG_INVALID;
430	}
431	if (pci->pcPathLengthConstraint) {
432	x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint);
433	} else
434	x->ex_pcpathlen = -1;
435	PROXY_CERT_INFO_EXTENSION_free(pci);
436	x->ex_flags \|= EXFLAG_PROXY;
437	} else if (i != -1) {
438	x->ex_flags \|= EXFLAG_INVALID;
439	}
440	/* Handle key usage */
441	if ((usage = X509_get_ext_d2i(x, NID_key_usage, &i, NULL))) {
442	if (usage->length > 0) {
443	x->ex_kusage = usage->data[0];
444	if (usage->length > 1)
445	x->ex_kusage \|= usage->data[1] << 8;
446	} else
447	x->ex_kusage = 0;
448	x->ex_flags \|= EXFLAG_KUSAGE;
449	ASN1_BIT_STRING_free(usage);
450	} else if (i != -1) {
451	x->ex_flags \|= EXFLAG_INVALID;
452	}
453	x->ex_xkusage = 0;
454	if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, &i, NULL))) {
455	x->ex_flags \|= EXFLAG_XKUSAGE;
456	for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
457	switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) {
458	case NID_server_auth:
459	x->ex_xkusage \|= XKU_SSL_SERVER;
460	break;
461
462	case NID_client_auth:
463	x->ex_xkusage \|= XKU_SSL_CLIENT;
464	break;
465
466	case NID_email_protect:
467	x->ex_xkusage \|= XKU_SMIME;
468	break;
469
470	case NID_code_sign:
471	x->ex_xkusage \|= XKU_CODE_SIGN;
472	break;
473
474	case NID_ms_sgc:
475	case NID_ns_sgc:
476	x->ex_xkusage \|= XKU_SGC;
477	break;
478
479	case NID_OCSP_sign:
480	x->ex_xkusage \|= XKU_OCSP_SIGN;
481	break;
482
483	case NID_time_stamp:
484	x->ex_xkusage \|= XKU_TIMESTAMP;
485	break;
486
487	case NID_dvcs:
488	x->ex_xkusage \|= XKU_DVCS;
489	break;
490
491	case NID_anyExtendedKeyUsage:
492	x->ex_xkusage \|= XKU_ANYEKU;
493	break;
494	}
495	}
496	sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
497	} else if (i != -1) {
498	x->ex_flags \|= EXFLAG_INVALID;
499	}
500
501	if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, &i, NULL))) {
502	if (ns->length > 0)
503	x->ex_nscert = ns->data[0];
504	else
505	x->ex_nscert = 0;
506	x->ex_flags \|= EXFLAG_NSCERT;
507	ASN1_BIT_STRING_free(ns);
508	} else if (i != -1) {
509	x->ex_flags \|= EXFLAG_INVALID;
510	}
511	x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, &i, NULL);
512	if (x->skid == NULL && i != -1)
513	x->ex_flags \|= EXFLAG_INVALID;
514	x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, &i, NULL);
515	if (x->akid == NULL && i != -1)
516	x->ex_flags \|= EXFLAG_INVALID;
517	/* Does subject name match issuer ? */
518	if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) {
519	x->ex_flags \|= EXFLAG_SI; /* cert is self-issued */
520	if (X509_check_akid(x, x->akid) == X509_V_OK /* SKID matches AKID */
521	/* .. and the signature alg matches the PUBKEY alg: */
522	&& check_sig_alg_match(X509_get0_pubkey(x), x) == X509_V_OK)
523	x->ex_flags \|= EXFLAG_SS; /* indicate self-signed */
524	}
525	x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, &i, NULL);
526	if (x->altname == NULL && i != -1)
527	x->ex_flags \|= EXFLAG_INVALID;
528	x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL);
529	if (x->nc == NULL && i != -1)
530	x->ex_flags \|= EXFLAG_INVALID;
531	if (!setup_crldp(x))
532	x->ex_flags \|= EXFLAG_INVALID;
533
534	#ifndef OPENSSL_NO_RFC3779
535	x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, &i, NULL);
536	if (x->rfc3779_addr == NULL && i != -1)
537	x->ex_flags \|= EXFLAG_INVALID;
538	x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum, &i, NULL);
539	if (x->rfc3779_asid == NULL && i != -1)
540	x->ex_flags \|= EXFLAG_INVALID;
541	#endif
542	for (i = 0; i < X509_get_ext_count(x); i++) {
543	ex = X509_get_ext(x, i);
544	if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
545	== NID_freshest_crl)
546	x->ex_flags \|= EXFLAG_FRESHEST;
547	if (!X509_EXTENSION_get_critical(ex))
548	continue;
549	if (!X509_supported_extension(ex)) {
550	x->ex_flags \|= EXFLAG_CRITICAL;
551	break;
552	}
553	}
554	x509_init_sig_info(x);
555	x->ex_flags \|= EXFLAG_SET;
556	#ifdef tsan_st_rel
557	tsan_st_rel((TSAN_QUALIFIER int *)&x->ex_cached, 1);
558	/*
559	* Above store triggers fast lock-free check in the beginning of the
560	* function. But one has to ensure that the structure is "stable", i.e.
561	* all stores are visible on all processors. Hence the release fence.
562	*/
563	#endif
564	CRYPTO_THREAD_unlock(x->lock);
565	}
566
567	/*-
568	* CA checks common to all purposes
569	* return codes:
570	* 0 not a CA
571	* 1 is a CA
572	* 2 Only possible in older versions of openSSL when basicConstraints are absent
573	* new versions will not return this value. May be a CA
574	* 3 basicConstraints absent but self signed V1.
575	* 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
576	* 5 Netscape specific CA Flags present
577	*/
578
579	static int check_ca(const X509 *x)
580	{
581	/* keyUsage if present should allow cert signing */
582	if (ku_reject(x, KU_KEY_CERT_SIGN))
583	return 0;
584	if (x->ex_flags & EXFLAG_BCONS) {
585	if (x->ex_flags & EXFLAG_CA)
586	return 1;
587	/* If basicConstraints says not a CA then say so */
588	else
589	return 0;
590	} else {
591	/* we support V1 roots for... uh, I don't really know why. */
592	if ((x->ex_flags & V1_ROOT) == V1_ROOT)
593	return 3;
594	/*
595	* If key usage present it must have certSign so tolerate it
596	*/
597	else if (x->ex_flags & EXFLAG_KUSAGE)
598	return 4;
599	/* Older certificates could have Netscape-specific CA types */
600	else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA)
601	return 5;
602	/* can this still be regarded a CA certificate? I doubt it */
603	return 0;
604	}
605	}
606
607	void X509_set_proxy_flag(X509 *x)
608	{
609	x->ex_flags \|= EXFLAG_PROXY;
610	}
611
612	void X509_set_proxy_pathlen(X509 *x, long l)
613	{
614	x->ex_pcpathlen = l;
615	}
616
617	int X509_check_ca(X509 *x)
618	{
619	x509v3_cache_extensions(x);
620
621	return check_ca(x);
622	}
623
624	/* Check SSL CA: common checks for SSL client and server */
625	static int check_ssl_ca(const X509 *x)
626	{
627	int ca_ret;
628	ca_ret = check_ca(x);
629	if (!ca_ret)
630	return 0;
631	/* check nsCertType if present */
632	if (ca_ret != 5 \|\| x->ex_nscert & NS_SSL_CA)
633	return ca_ret;
634	else
635	return 0;
636	}
637
638	static int check_purpose_ssl_client(const X509_PURPOSE xp, const X509 x,
639	int ca)
640	{
641	if (xku_reject(x, XKU_SSL_CLIENT))
642	return 0;
643	if (ca)
644	return check_ssl_ca(x);
645	/* We need to do digital signatures or key agreement */
646	if (ku_reject(x, KU_DIGITAL_SIGNATURE \| KU_KEY_AGREEMENT))
647	return 0;
648	/* nsCertType if present should allow SSL client use */
649	if (ns_reject(x, NS_SSL_CLIENT))
650	return 0;
651	return 1;
652	}
653
654	/*
655	* Key usage needed for TLS/SSL server: digital signature, encipherment or
656	* key agreement. The ssl code can check this more thoroughly for individual
657	* key types.
658	*/
659	#define KU_TLS \
660	KU_DIGITAL_SIGNATURE\|KU_KEY_ENCIPHERMENT\|KU_KEY_AGREEMENT
661
662	static int check_purpose_ssl_server(const X509_PURPOSE xp, const X509 x,
663	int ca)
664	{
665	if (xku_reject(x, XKU_SSL_SERVER \| XKU_SGC))
666	return 0;
667	if (ca)
668	return check_ssl_ca(x);
669
670	if (ns_reject(x, NS_SSL_SERVER))
671	return 0;
672	if (ku_reject(x, KU_TLS))
673	return 0;
674
675	return 1;
676
677	}
678
679	static int check_purpose_ns_ssl_server(const X509_PURPOSE xp, const X509 x,
680	int ca)
681	{
682	int ret;
683	ret = check_purpose_ssl_server(xp, x, ca);
684	if (!ret \|\| ca)
685	return ret;
686	/* We need to encipher or Netscape complains */
687	if (ku_reject(x, KU_KEY_ENCIPHERMENT))
688	return 0;
689	return ret;
690	}
691
692	/* common S/MIME checks */
693	static int purpose_smime(const X509 *x, int ca)
694	{
695	if (xku_reject(x, XKU_SMIME))
696	return 0;
697	if (ca) {
698	int ca_ret;
699	ca_ret = check_ca(x);
700	if (!ca_ret)
701	return 0;
702	/* check nsCertType if present */
703	if (ca_ret != 5 \|\| x->ex_nscert & NS_SMIME_CA)
704	return ca_ret;
705	else
706	return 0;
707	}
708	if (x->ex_flags & EXFLAG_NSCERT) {
709	if (x->ex_nscert & NS_SMIME)
710	return 1;
711	/* Workaround for some buggy certificates */
712	if (x->ex_nscert & NS_SSL_CLIENT)
713	return 2;
714	return 0;
715	}
716	return 1;
717	}
718
719	static int check_purpose_smime_sign(const X509_PURPOSE xp, const X509 x,
720	int ca)
721	{
722	int ret;
723	ret = purpose_smime(x, ca);
724	if (!ret \|\| ca)
725	return ret;
726	if (ku_reject(x, KU_DIGITAL_SIGNATURE \| KU_NON_REPUDIATION))
727	return 0;
728	return ret;
729	}
730
731	static int check_purpose_smime_encrypt(const X509_PURPOSE xp, const X509 x,
732	int ca)
733	{
734	int ret;
735	ret = purpose_smime(x, ca);
736	if (!ret \|\| ca)
737	return ret;
738	if (ku_reject(x, KU_KEY_ENCIPHERMENT))
739	return 0;
740	return ret;
741	}
742
743	static int check_purpose_crl_sign(const X509_PURPOSE xp, const X509 x,
744	int ca)
745	{
746	if (ca) {
747	int ca_ret;
748	if ((ca_ret = check_ca(x)) != 2)
749	return ca_ret;
750	else
751	return 0;
752	}
753	if (ku_reject(x, KU_CRL_SIGN))
754	return 0;
755	return 1;
756	}
757
758	/*
759	* OCSP helper: this is not a full OCSP check. It just checks that each CA
760	* is valid. Additional checks must be made on the chain.
761	*/
762
763	static int ocsp_helper(const X509_PURPOSE xp, const X509 x, int ca)
764	{
765	/*
766	* Must be a valid CA. Should we really support the "I don't know" value
767	* (2)?
768	*/
769	if (ca)
770	return check_ca(x);
771	/* leaf certificate is checked in OCSP_verify() */
772	return 1;
773	}
774
775	static int check_purpose_timestamp_sign(const X509_PURPOSE xp, const X509 x,
776	int ca)
777	{
778	int i_ext;
779
780	/* If ca is true we must return if this is a valid CA certificate. */
781	if (ca)
782	return check_ca(x);
783
784	/*
785	* Check the optional key usage field:
786	* if Key Usage is present, it must be one of digitalSignature
787	* and/or nonRepudiation (other values are not consistent and shall
788	* be rejected).
789	*/
790	if ((x->ex_flags & EXFLAG_KUSAGE)
791	&& ((x->ex_kusage & ~(KU_NON_REPUDIATION \| KU_DIGITAL_SIGNATURE)) \|\|
792	!(x->ex_kusage & (KU_NON_REPUDIATION \| KU_DIGITAL_SIGNATURE))))
793	return 0;
794
795	/* Only time stamp key usage is permitted and it's required. */
796	if (!(x->ex_flags & EXFLAG_XKUSAGE) \|\| x->ex_xkusage != XKU_TIMESTAMP)
797	return 0;
798
799	/* Extended Key Usage MUST be critical */
800	i_ext = X509_get_ext_by_NID(x, NID_ext_key_usage, -1);
801	if (i_ext >= 0) {
802	X509_EXTENSION ext = X509_get_ext((X509 )x, i_ext);
803	if (!X509_EXTENSION_get_critical(ext))
804	return 0;
805	}
806
807	return 1;
808	}
809
810	static int no_check(const X509_PURPOSE xp, const X509 x, int ca)
811	{
812	return 1;
813	}
814
815	/*-
816	* Check if certificate I<issuer> is allowed to issue certificate I<subject>
817	* according to the B<keyUsage> field of I<issuer> if present
818	* depending on any proxyCertInfo extension of I<subject>.
819	* Returns 0 for OK, or positive for reason for rejection
820	* where reason codes match those for X509_verify_cert().
821	*/
822	int x509_signing_allowed(const X509 issuer, const X509 subject)
823	{
824	if (subject->ex_flags & EXFLAG_PROXY) {
825	if (ku_reject(issuer, KU_DIGITAL_SIGNATURE))
826	return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
827	} else if (ku_reject(issuer, KU_KEY_CERT_SIGN))
828	return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
829	return X509_V_OK;
830	}
831
832	/*-
833	* Various checks to see if one certificate issued the second.
834	* This can be used to prune a set of possible issuer certificates
835	* which have been looked up using some simple method such as by
836	* subject name.
837	* These are:
838	* 1. Check issuer_name(subject) == subject_name(issuer)
839	* 2. If akid(subject) exists check it matches issuer
840	* 3. Check that issuer public key algorithm matches subject signature algorithm
841	* 4. If key_usage(issuer) exists check it supports certificate signing
842	* returns 0 for OK, positive for reason for mismatch, reasons match
843	* codes for X509_verify_cert()
844	*/
845
846	int X509_check_issued(X509 issuer, X509 subject)
847	{
848	int ret;
849
850	if ((ret = x509_likely_issued(issuer, subject)) != X509_V_OK)
851	return ret;
852	return x509_signing_allowed(issuer, subject);
853	}
854
855	/* do the checks 1., 2., and 3. as described above for X509_check_issued() */
856	int x509_likely_issued(X509 issuer, X509 subject)
857	{
858	if (X509_NAME_cmp(X509_get_subject_name(issuer),
859	X509_get_issuer_name(subject)))
860	return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
861
862	x509v3_cache_extensions(issuer);
863	if (issuer->ex_flags & EXFLAG_INVALID)
864	return X509_V_ERR_UNSPECIFIED;
865	x509v3_cache_extensions(subject);
866	if (subject->ex_flags & EXFLAG_INVALID)
867	return X509_V_ERR_UNSPECIFIED;
868
869	if (subject->akid) {
870	int ret = X509_check_akid(issuer, subject->akid);
871	if (ret != X509_V_OK)
872	return ret;
873	}
874
875	/* check if the subject signature alg matches the issuer's PUBKEY alg */
876	return check_sig_alg_match(X509_get0_pubkey(issuer), subject);
877	}
878
879	int X509_check_akid(X509 issuer, AUTHORITY_KEYID akid)
880	{
881
882	if (!akid)
883	return X509_V_OK;
884
885	/* Check key ids (if present) */
886	if (akid->keyid && issuer->skid &&
887	ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid))
888	return X509_V_ERR_AKID_SKID_MISMATCH;
889	/* Check serial number */
890	if (akid->serial &&
891	ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
892	return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
893	/* Check issuer name */
894	if (akid->issuer) {
895	/*
896	* Ugh, for some peculiar reason AKID includes SEQUENCE OF
897	* GeneralName. So look for a DirName. There may be more than one but
898	* we only take any notice of the first.
899	*/
900	GENERAL_NAMES *gens;
901	GENERAL_NAME *gen;
902	X509_NAME *nm = NULL;
903	int i;
904	gens = akid->issuer;
905	for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
906	gen = sk_GENERAL_NAME_value(gens, i);
907	if (gen->type == GEN_DIRNAME) {
908	nm = gen->d.dirn;
909	break;
910	}
911	}
912	if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
913	return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
914	}
915	return X509_V_OK;
916	}
917
918	uint32_t X509_get_extension_flags(X509 *x)
919	{
920	/* Call for side-effect of computing hash and caching extensions */
921	X509_check_purpose(x, -1, -1);
922	return x->ex_flags;
923	}
924
925	uint32_t X509_get_key_usage(X509 *x)
926	{
927	/* Call for side-effect of computing hash and caching extensions */
928	if (X509_check_purpose(x, -1, -1) != 1)
929	return 0;
930	if (x->ex_flags & EXFLAG_KUSAGE)
931	return x->ex_kusage;
932	return UINT32_MAX;
933	}
934
935	uint32_t X509_get_extended_key_usage(X509 *x)
936	{
937	/* Call for side-effect of computing hash and caching extensions */
938	if (X509_check_purpose(x, -1, -1) != 1)
939	return 0;
940	if (x->ex_flags & EXFLAG_XKUSAGE)
941	return x->ex_xkusage;
942	return UINT32_MAX;
943	}
944
945	const ASN1_OCTET_STRING X509_get0_subject_key_id(X509 x)
946	{
947	/* Call for side-effect of computing hash and caching extensions */
948	if (X509_check_purpose(x, -1, -1) != 1)
949	return NULL;
950	return x->skid;
951	}
952
953	const ASN1_OCTET_STRING X509_get0_authority_key_id(X509 x)
954	{
955	/* Call for side-effect of computing hash and caching extensions */
956	if (X509_check_purpose(x, -1, -1) != 1)
957	return NULL;
958	return (x->akid != NULL ? x->akid->keyid : NULL);
959	}
960
961	const GENERAL_NAMES X509_get0_authority_issuer(X509 x)
962	{
963	/* Call for side-effect of computing hash and caching extensions */
964	if (X509_check_purpose(x, -1, -1) != 1)
965	return NULL;
966	return (x->akid != NULL ? x->akid->issuer : NULL);
967	}
968
969	const ASN1_INTEGER X509_get0_authority_serial(X509 x)
970	{
971	/* Call for side-effect of computing hash and caching extensions */
972	if (X509_check_purpose(x, -1, -1) != 1)
973	return NULL;
974	return (x->akid != NULL ? x->akid->serial : NULL);
975	}
976
977	long X509_get_pathlen(X509 *x)
978	{
979	/* Called for side effect of caching extensions */
980	if (X509_check_purpose(x, -1, -1) != 1
981	\|\| (x->ex_flags & EXFLAG_BCONS) == 0)
982	return -1;
983	return x->ex_pathlen;
984	}
985
986	long X509_get_proxy_pathlen(X509 *x)
987	{
988	/* Called for side effect of caching extensions */
989	if (X509_check_purpose(x, -1, -1) != 1
990	\|\| (x->ex_flags & EXFLAG_PROXY) == 0)
991	return -1;
992	return x->ex_pcpathlen;
993	}

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source: vbox/trunk/src/libs/openssl-1.1.1l/crypto/x509v3/v3_purp.c@ 91772

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