1 /*
2 * Copyright 1999-2023 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 <openssl/x509v3.h>
13 #include "crypto/x509.h"
14
15 static int tr_cmp(const X509_TRUST *const *a, const X509_TRUST *const *b);
16 static void trtable_free(X509_TRUST *p);
17
18 static int trust_1oidany(X509_TRUST *trust, X509 *x, int flags);
19 static int trust_1oid(X509_TRUST *trust, X509 *x, int flags);
20 static int trust_compat(X509_TRUST *trust, X509 *x, int flags);
21
22 static int obj_trust(int id, X509 *x, int flags);
23 static int (*default_trust)(int id, X509 *x, int flags) = obj_trust;
24
25 /*
26 * WARNING: the following table should be kept in order of trust and without
27 * any gaps so we can just subtract the minimum trust value to get an index
28 * into the table
29 */
30
31 static X509_TRUST trstandard[] = {
32 { X509_TRUST_COMPAT, 0, trust_compat, "compatible", 0, NULL },
33 { X509_TRUST_SSL_CLIENT, 0, trust_1oidany, "SSL Client", NID_client_auth,
34 NULL },
35 { X509_TRUST_SSL_SERVER, 0, trust_1oidany, "SSL Server", NID_server_auth,
36 NULL },
37 { X509_TRUST_EMAIL, 0, trust_1oidany, "S/MIME email", NID_email_protect,
38 NULL },
39 { X509_TRUST_OBJECT_SIGN, 0, trust_1oidany, "Object Signer", NID_code_sign,
40 NULL },
41 { X509_TRUST_OCSP_SIGN, 0, trust_1oid, "OCSP responder", NID_OCSP_sign,
42 NULL },
43 { X509_TRUST_OCSP_REQUEST, 0, trust_1oid, "OCSP request", NID_ad_OCSP,
44 NULL },
45 { X509_TRUST_TSA, 0, trust_1oidany, "TSA server", NID_time_stamp, NULL }
46 };
47
48 #define X509_TRUST_COUNT OSSL_NELEM(trstandard)
49
50 static STACK_OF(X509_TRUST) *trtable = NULL;
51
tr_cmp(const X509_TRUST * const * a,const X509_TRUST * const * b)52 static int tr_cmp(const X509_TRUST *const *a, const X509_TRUST *const *b)
53 {
54 return (*a)->trust - (*b)->trust;
55 }
56
X509_TRUST_set_default(int (* trust)(int,X509 *,int))57 int (*X509_TRUST_set_default(int (*trust)(int, X509 *, int)))(int, X509 *,
58 int)
59 {
60 int (*oldtrust)(int, X509 *, int);
61 oldtrust = default_trust;
62 default_trust = trust;
63 return oldtrust;
64 }
65
66 /* Returns X509_TRUST_TRUSTED, X509_TRUST_REJECTED, or X509_TRUST_UNTRUSTED */
X509_check_trust(X509 * x,int id,int flags)67 int X509_check_trust(X509 *x, int id, int flags)
68 {
69 X509_TRUST *pt;
70 int idx;
71
72 /* We get this as a default value */
73 if (id == X509_TRUST_DEFAULT)
74 return obj_trust(NID_anyExtendedKeyUsage, x,
75 flags | X509_TRUST_DO_SS_COMPAT);
76 idx = X509_TRUST_get_by_id(id);
77 if (idx < 0)
78 return default_trust(id, x, flags);
79 pt = X509_TRUST_get0(idx);
80 return pt->check_trust(pt, x, flags);
81 }
82
X509_TRUST_get_count(void)83 int X509_TRUST_get_count(void)
84 {
85 if (!trtable)
86 return X509_TRUST_COUNT;
87 return sk_X509_TRUST_num(trtable) + X509_TRUST_COUNT;
88 }
89
X509_TRUST_get0(int idx)90 X509_TRUST *X509_TRUST_get0(int idx)
91 {
92 if (idx < 0)
93 return NULL;
94 if (idx < (int)X509_TRUST_COUNT)
95 return trstandard + idx;
96 return sk_X509_TRUST_value(trtable, idx - X509_TRUST_COUNT);
97 }
98
X509_TRUST_get_by_id(int id)99 int X509_TRUST_get_by_id(int id)
100 {
101 X509_TRUST tmp;
102 int idx;
103
104 if ((id >= X509_TRUST_MIN) && (id <= X509_TRUST_MAX))
105 return id - X509_TRUST_MIN;
106 if (trtable == NULL)
107 return -1;
108 tmp.trust = id;
109 /* Ideally, this would be done under lock */
110 sk_X509_TRUST_sort(trtable);
111 idx = sk_X509_TRUST_find(trtable, &tmp);
112 if (idx < 0)
113 return -1;
114 return idx + X509_TRUST_COUNT;
115 }
116
X509_TRUST_set(int * t,int trust)117 int X509_TRUST_set(int *t, int trust)
118 {
119 if (X509_TRUST_get_by_id(trust) < 0) {
120 ERR_raise(ERR_LIB_X509, X509_R_INVALID_TRUST);
121 return 0;
122 }
123 *t = trust;
124 return 1;
125 }
126
X509_TRUST_add(int id,int flags,int (* ck)(X509_TRUST *,X509 *,int),const char * name,int arg1,void * arg2)127 int X509_TRUST_add(int id, int flags, int (*ck)(X509_TRUST *, X509 *, int),
128 const char *name, int arg1, void *arg2)
129 {
130 int idx;
131 X509_TRUST *trtmp;
132 /*
133 * This is set according to what we change: application can't set it
134 */
135 flags &= ~X509_TRUST_DYNAMIC;
136 /* This will always be set for application modified trust entries */
137 flags |= X509_TRUST_DYNAMIC_NAME;
138 /* Get existing entry if any */
139 idx = X509_TRUST_get_by_id(id);
140 /* Need a new entry */
141 if (idx < 0) {
142 if ((trtmp = OPENSSL_malloc(sizeof(*trtmp))) == NULL)
143 return 0;
144 trtmp->flags = X509_TRUST_DYNAMIC;
145 } else
146 trtmp = X509_TRUST_get0(idx);
147
148 /* OPENSSL_free existing name if dynamic */
149 if (trtmp->flags & X509_TRUST_DYNAMIC_NAME)
150 OPENSSL_free(trtmp->name);
151 /* dup supplied name */
152 if ((trtmp->name = OPENSSL_strdup(name)) == NULL)
153 goto err;
154 /* Keep the dynamic flag of existing entry */
155 trtmp->flags &= X509_TRUST_DYNAMIC;
156 /* Set all other flags */
157 trtmp->flags |= flags;
158
159 trtmp->trust = id;
160 trtmp->check_trust = ck;
161 trtmp->arg1 = arg1;
162 trtmp->arg2 = arg2;
163
164 /* If its a new entry manage the dynamic table */
165 if (idx < 0) {
166 if (trtable == NULL
167 && (trtable = sk_X509_TRUST_new(tr_cmp)) == NULL) {
168 ERR_raise(ERR_LIB_X509, ERR_R_CRYPTO_LIB);
169 goto err;
170 }
171 if (!sk_X509_TRUST_push(trtable, trtmp)) {
172 ERR_raise(ERR_LIB_X509, ERR_R_CRYPTO_LIB);
173 goto err;
174 }
175 }
176 return 1;
177 err:
178 if (idx < 0) {
179 OPENSSL_free(trtmp->name);
180 OPENSSL_free(trtmp);
181 }
182 return 0;
183 }
184
trtable_free(X509_TRUST * p)185 static void trtable_free(X509_TRUST *p)
186 {
187 if (p == NULL)
188 return;
189 if (p->flags & X509_TRUST_DYNAMIC) {
190 if (p->flags & X509_TRUST_DYNAMIC_NAME)
191 OPENSSL_free(p->name);
192 OPENSSL_free(p);
193 }
194 }
195
X509_TRUST_cleanup(void)196 void X509_TRUST_cleanup(void)
197 {
198 sk_X509_TRUST_pop_free(trtable, trtable_free);
199 trtable = NULL;
200 }
201
X509_TRUST_get_flags(const X509_TRUST * xp)202 int X509_TRUST_get_flags(const X509_TRUST *xp)
203 {
204 return xp->flags;
205 }
206
X509_TRUST_get0_name(const X509_TRUST * xp)207 char *X509_TRUST_get0_name(const X509_TRUST *xp)
208 {
209 return xp->name;
210 }
211
X509_TRUST_get_trust(const X509_TRUST * xp)212 int X509_TRUST_get_trust(const X509_TRUST *xp)
213 {
214 return xp->trust;
215 }
216
trust_1oidany(X509_TRUST * trust,X509 * x,int flags)217 static int trust_1oidany(X509_TRUST *trust, X509 *x, int flags)
218 {
219 /*
220 * Declare the chain verified if the desired trust OID is not rejected in
221 * any auxiliary trust info for this certificate, and the OID is either
222 * expressly trusted, or else either "anyEKU" is trusted, or the
223 * certificate is self-signed and X509_TRUST_NO_SS_COMPAT is not set.
224 */
225 flags |= X509_TRUST_DO_SS_COMPAT | X509_TRUST_OK_ANY_EKU;
226 return obj_trust(trust->arg1, x, flags);
227 }
228
trust_1oid(X509_TRUST * trust,X509 * x,int flags)229 static int trust_1oid(X509_TRUST *trust, X509 *x, int flags)
230 {
231 /*
232 * Declare the chain verified only if the desired trust OID is not
233 * rejected and is expressly trusted. Neither "anyEKU" nor "compat"
234 * trust in self-signed certificates apply.
235 */
236 flags &= ~(X509_TRUST_DO_SS_COMPAT | X509_TRUST_OK_ANY_EKU);
237 return obj_trust(trust->arg1, x, flags);
238 }
239
trust_compat(X509_TRUST * trust,X509 * x,int flags)240 static int trust_compat(X509_TRUST *trust, X509 *x, int flags)
241 {
242 /* Call for side-effect of setting EXFLAG_SS for self-signed-certs */
243 if (X509_check_purpose(x, -1, 0) != 1)
244 return X509_TRUST_UNTRUSTED;
245 if ((flags & X509_TRUST_NO_SS_COMPAT) == 0 && (x->ex_flags & EXFLAG_SS))
246 return X509_TRUST_TRUSTED;
247 else
248 return X509_TRUST_UNTRUSTED;
249 }
250
obj_trust(int id,X509 * x,int flags)251 static int obj_trust(int id, X509 *x, int flags)
252 {
253 X509_CERT_AUX *ax = x->aux;
254 int i;
255
256 if (ax != NULL && ax->reject != NULL) {
257 for (i = 0; i < sk_ASN1_OBJECT_num(ax->reject); i++) {
258 ASN1_OBJECT *obj = sk_ASN1_OBJECT_value(ax->reject, i);
259 int nid = OBJ_obj2nid(obj);
260
261 if (nid == id || (nid == NID_anyExtendedKeyUsage && (flags & X509_TRUST_OK_ANY_EKU)))
262 return X509_TRUST_REJECTED;
263 }
264 }
265
266 if (ax != NULL && ax->trust != NULL) {
267 for (i = 0; i < sk_ASN1_OBJECT_num(ax->trust); i++) {
268 ASN1_OBJECT *obj = sk_ASN1_OBJECT_value(ax->trust, i);
269 int nid = OBJ_obj2nid(obj);
270
271 if (nid == id || (nid == NID_anyExtendedKeyUsage && (flags & X509_TRUST_OK_ANY_EKU)))
272 return X509_TRUST_TRUSTED;
273 }
274 /*
275 * Reject when explicit trust EKU are set and none match.
276 *
277 * Returning untrusted is enough for full chains that end in
278 * self-signed roots, because when explicit trust is specified it
279 * suppresses the default blanket trust of self-signed objects.
280 *
281 * But for partial chains, this is not enough, because absent a similar
282 * trust-self-signed policy, non matching EKUs are indistinguishable
283 * from lack of EKU constraints.
284 *
285 * Therefore, failure to match any trusted purpose must trigger an
286 * explicit reject.
287 */
288 return X509_TRUST_REJECTED;
289 }
290
291 if ((flags & X509_TRUST_DO_SS_COMPAT) == 0)
292 return X509_TRUST_UNTRUSTED;
293
294 /*
295 * Not rejected, and there is no list of accepted uses, try compat.
296 */
297 return trust_compat(NULL, x, flags);
298 }
299