crypto/x509/x509_trs.c

   1 /*
   2  * Copyright 1999-2016 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 <openssl/x509v3.h>
  13 #include "internal/x509_int.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
  52 static int tr_cmp(const X509_TRUST *const *a, const X509_TRUST *const *b)
  53 {
  54     return (*a)->trust - (*b)->trust;
  55 }
  56
  57 int (*X509_TRUST_set_default(int (*trust) (int, X509 *, int))) (int, X509 *,
  58                                                                 int) {
  59     int (*oldtrust) (int, X509 *, int);
  60     oldtrust = default_trust;
  61     default_trust = trust;
  62     return oldtrust;
  63 }
  64
  65 int X509_check_trust(X509 *x, int id, int flags)
  66 {
  67     X509_TRUST *pt;
  68     int idx;
  69
  70     /* We get this as a default value */
  71     if (id == X509_TRUST_DEFAULT)
  72         return obj_trust(NID_anyExtendedKeyUsage, x,
  73                          flags | X509_TRUST_DO_SS_COMPAT);
  74     idx = X509_TRUST_get_by_id(id);
  75     if (idx == -1)
  76         return default_trust(id, x, flags);
  77     pt = X509_TRUST_get0(idx);
  78     return pt->check_trust(pt, x, flags);
  79 }
  80
  81 int X509_TRUST_get_count(void)
  82 {
  83     if (!trtable)
  84         return X509_TRUST_COUNT;
  85     return sk_X509_TRUST_num(trtable) + X509_TRUST_COUNT;
  86 }
  87
  88 X509_TRUST *X509_TRUST_get0(int idx)
  89 {
  90     if (idx < 0)
  91         return NULL;
  92     if (idx < (int)X509_TRUST_COUNT)
  93         return trstandard + idx;
  94     return sk_X509_TRUST_value(trtable, idx - X509_TRUST_COUNT);
  95 }
  96
  97 int X509_TRUST_get_by_id(int id)
  98 {
  99     X509_TRUST tmp;
 100     int idx;
 101     if ((id >= X509_TRUST_MIN) && (id <= X509_TRUST_MAX))
 102         return id - X509_TRUST_MIN;
 103     tmp.trust = id;
 104     if (!trtable)
 105         return -1;
 106     idx = sk_X509_TRUST_find(trtable, &tmp);
 107     if (idx == -1)
 108         return -1;
 109     return idx + X509_TRUST_COUNT;
 110 }
 111
 112 int X509_TRUST_set(int *t, int trust)
 113 {
 114     if (X509_TRUST_get_by_id(trust) == -1) {
 115         X509err(X509_F_X509_TRUST_SET, X509_R_INVALID_TRUST);
 116         return 0;
 117     }
 118     *t = trust;
 119     return 1;
 120 }
 121
 122 int X509_TRUST_add(int id, int flags, int (*ck) (X509_TRUST *, X509 *, int),
 123                    char *name, int arg1, void *arg2)
 124 {
 125     int idx;
 126     X509_TRUST *trtmp;
 127     /*
 128      * This is set according to what we change: application can't set it
 129      */
 130     flags &= ~X509_TRUST_DYNAMIC;
 131     /* This will always be set for application modified trust entries */
 132     flags |= X509_TRUST_DYNAMIC_NAME;
 133     /* Get existing entry if any */
 134     idx = X509_TRUST_get_by_id(id);
 135     /* Need a new entry */
 136     if (idx == -1) {
 137         if ((trtmp = OPENSSL_malloc(sizeof(*trtmp))) == NULL) {
 138             X509err(X509_F_X509_TRUST_ADD, ERR_R_MALLOC_FAILURE);
 139             return 0;
 140         }
 141         trtmp->flags = X509_TRUST_DYNAMIC;
 142     } else
 143         trtmp = X509_TRUST_get0(idx);
 144
 145     /* OPENSSL_free existing name if dynamic */
 146     if (trtmp->flags & X509_TRUST_DYNAMIC_NAME)
 147         OPENSSL_free(trtmp->name);
 148     /* dup supplied name */
 149     if ((trtmp->name = OPENSSL_strdup(name)) == NULL) {
 150         X509err(X509_F_X509_TRUST_ADD, ERR_R_MALLOC_FAILURE);
 151         return 0;
 152     }
 153     /* Keep the dynamic flag of existing entry */
 154     trtmp->flags &= X509_TRUST_DYNAMIC;
 155     /* Set all other flags */
 156     trtmp->flags |= flags;
 157
 158     trtmp->trust = id;
 159     trtmp->check_trust = ck;
 160     trtmp->arg1 = arg1;
 161     trtmp->arg2 = arg2;
 162
 163     /* If its a new entry manage the dynamic table */
 164     if (idx == -1) {
 165         if (trtable == NULL
 166             && (trtable = sk_X509_TRUST_new(tr_cmp)) == NULL) {
 167             X509err(X509_F_X509_TRUST_ADD, ERR_R_MALLOC_FAILURE);
 168             return 0;
 169         }
 170         if (!sk_X509_TRUST_push(trtable, trtmp)) {
 171             X509err(X509_F_X509_TRUST_ADD, ERR_R_MALLOC_FAILURE);
 172             return 0;
 173         }
 174     }
 175     return 1;
 176 }
 177
 178 static void trtable_free(X509_TRUST *p)
 179 {
 180     if (!p)
 181         return;
 182     if (p->flags & X509_TRUST_DYNAMIC) {
 183         if (p->flags & X509_TRUST_DYNAMIC_NAME)
 184             OPENSSL_free(p->name);
 185         OPENSSL_free(p);
 186     }
 187 }
 188
 189 void X509_TRUST_cleanup(void)
 190 {
 191     unsigned int i;
 192     for (i = 0; i < X509_TRUST_COUNT; i++)
 193         trtable_free(trstandard + i);
 194     sk_X509_TRUST_pop_free(trtable, trtable_free);
 195     trtable = NULL;
 196 }
 197
 198 int X509_TRUST_get_flags(X509_TRUST *xp)
 199 {
 200     return xp->flags;
 201 }
 202
 203 char *X509_TRUST_get0_name(X509_TRUST *xp)
 204 {
 205     return xp->name;
 206 }
 207
 208 int X509_TRUST_get_trust(X509_TRUST *xp)
 209 {
 210     return xp->trust;
 211 }
 212
 213 static int trust_1oidany(X509_TRUST *trust, X509 *x, int flags)
 214 {
 215     /*
 216      * Declare the chain verified if the desired trust OID is not rejected in
 217      * any auxiliary trust info for this certificate, and the OID is either
 218      * expressly trusted, or else either "anyEKU" is trusted, or the
 219      * certificate is self-signed.
 220      */
 221     flags |= X509_TRUST_DO_SS_COMPAT | X509_TRUST_OK_ANY_EKU;
 222     return obj_trust(trust->arg1, x, flags);
 223 }
 224
 225 static int trust_1oid(X509_TRUST *trust, X509 *x, int flags)
 226 {
 227     /*
 228      * Declare the chain verified only if the desired trust OID is not
 229      * rejected and is expressly trusted.  Neither "anyEKU" nor "compat"
 230      * trust in self-signed certificates apply.
 231      */
 232     flags &= ~(X509_TRUST_DO_SS_COMPAT | X509_TRUST_OK_ANY_EKU);
 233     return obj_trust(trust->arg1, x, flags);
 234 }
 235
 236 static int trust_compat(X509_TRUST *trust, X509 *x, int flags)
 237 {
 238     /* Call for side-effect of computing hash and caching extensions */
 239     X509_check_purpose(x, -1, 0);
 240     if ((flags & X509_TRUST_NO_SS_COMPAT) == 0 && x->ex_flags & EXFLAG_SS)
 241         return X509_TRUST_TRUSTED;
 242     else
 243         return X509_TRUST_UNTRUSTED;
 244 }
 245
 246 static int obj_trust(int id, X509 *x, int flags)
 247 {
 248     X509_CERT_AUX *ax = x->aux;
 249     int i;
 250
 251     if (ax && ax->reject) {
 252         for (i = 0; i < sk_ASN1_OBJECT_num(ax->reject); i++) {
 253             ASN1_OBJECT *obj = sk_ASN1_OBJECT_value(ax->reject, i);
 254             int nid = OBJ_obj2nid(obj);
 255
 256             if (nid == id || (nid == NID_anyExtendedKeyUsage &&
 257                 (flags & X509_TRUST_OK_ANY_EKU)))
 258                 return X509_TRUST_REJECTED;
 259         }
 260     }
 261
 262     if (ax && ax->trust) {
 263         for (i = 0; i < sk_ASN1_OBJECT_num(ax->trust); i++) {
 264             ASN1_OBJECT *obj = sk_ASN1_OBJECT_value(ax->trust, i);
 265             int nid = OBJ_obj2nid(obj);
 266
 267             if (nid == id || (nid == NID_anyExtendedKeyUsage &&
 268                 (flags & X509_TRUST_OK_ANY_EKU)))
 269                 return X509_TRUST_TRUSTED;
 270         }
 271         /*
 272          * Reject when explicit trust EKU are set and none match.
 273          *
 274          * Returning untrusted is enough for for full chains that end in
 275          * self-signed roots, because when explicit trust is specified it
 276          * suppresses the default blanket trust of self-signed objects.
 277          *
 278          * But for partial chains, this is not enough, because absent a similar
 279          * trust-self-signed policy, non matching EKUs are indistinguishable
 280          * from lack of EKU constraints.
 281          *
 282          * Therefore, failure to match any trusted purpose must trigger an
 283          * explicit reject.
 284          */
 285         return X509_TRUST_REJECTED;
 286     }
 287
 288     if ((flags & X509_TRUST_DO_SS_COMPAT) == 0)
 289         return X509_TRUST_UNTRUSTED;
 290
 291     /*
 292      * Not rejected, and there is no list of accepted uses, try compat.
 293      */
 294     return trust_compat(NULL, x, flags);
 295 }