crypto/x509/x509_trs.c

   1 /*
   2  * Copyright 1999-2018 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
  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
 102     if ((id >= X509_TRUST_MIN) && (id <= X509_TRUST_MAX))
 103         return id - X509_TRUST_MIN;
 104     if (trtable == NULL)
 105         return -1;
 106     tmp.trust = id;
 107     idx = sk_X509_TRUST_find(trtable, &tmp);
 108     if (idx < 0)
 109         return -1;
 110     return idx + X509_TRUST_COUNT;
 111 }
 112
 113 int X509_TRUST_set(int *t, int trust)
 114 {
 115     if (X509_TRUST_get_by_id(trust) == -1) {
 116         X509err(X509_F_X509_TRUST_SET, X509_R_INVALID_TRUST);
 117         return 0;
 118     }
 119     *t = trust;
 120     return 1;
 121 }
 122
 123 int X509_TRUST_add(int id, int flags, int (*ck) (X509_TRUST *, X509 *, int),
 124                    const char *name, int arg1, void *arg2)
 125 {
 126     int idx;
 127     X509_TRUST *trtmp;
 128     /*
 129      * This is set according to what we change: application can't set it
 130      */
 131     flags &= ~X509_TRUST_DYNAMIC;
 132     /* This will always be set for application modified trust entries */
 133     flags |= X509_TRUST_DYNAMIC_NAME;
 134     /* Get existing entry if any */
 135     idx = X509_TRUST_get_by_id(id);
 136     /* Need a new entry */
 137     if (idx == -1) {
 138         if ((trtmp = OPENSSL_malloc(sizeof(*trtmp))) == NULL) {
 139             X509err(X509_F_X509_TRUST_ADD, ERR_R_MALLOC_FAILURE);
 140             return 0;
 141         }
 142         trtmp->flags = X509_TRUST_DYNAMIC;
 143     } else
 144         trtmp = X509_TRUST_get0(idx);
 145
 146     /* OPENSSL_free existing name if dynamic */
 147     if (trtmp->flags & X509_TRUST_DYNAMIC_NAME)
 148         OPENSSL_free(trtmp->name);
 149     /* dup supplied name */
 150     if ((trtmp->name = OPENSSL_strdup(name)) == NULL) {
 151         X509err(X509_F_X509_TRUST_ADD, ERR_R_MALLOC_FAILURE);
 152         goto err;
 153     }
 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 == -1) {
 166         if (trtable == NULL
 167             && (trtable = sk_X509_TRUST_new(tr_cmp)) == NULL) {
 168             X509err(X509_F_X509_TRUST_ADD, ERR_R_MALLOC_FAILURE);
 169             goto err;;
 170         }
 171         if (!sk_X509_TRUST_push(trtable, trtmp)) {
 172             X509err(X509_F_X509_TRUST_ADD, ERR_R_MALLOC_FAILURE);
 173             goto err;
 174         }
 175     }
 176     return 1;
 177  err:
 178     if (idx == -1) {
 179         OPENSSL_free(trtmp->name);
 180         OPENSSL_free(trtmp);
 181     }
 182     return 0;
 183 }
 184
 185 static void trtable_free(X509_TRUST *p)
 186 {
 187     if (!p)
 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
 196 void X509_TRUST_cleanup(void)
 197 {
 198     sk_X509_TRUST_pop_free(trtable, trtable_free);
 199     trtable = NULL;
 200 }
 201
 202 int X509_TRUST_get_flags(const X509_TRUST *xp)
 203 {
 204     return xp->flags;
 205 }
 206
 207 char *X509_TRUST_get0_name(const X509_TRUST *xp)
 208 {
 209     return xp->name;
 210 }
 211
 212 int X509_TRUST_get_trust(const X509_TRUST *xp)
 213 {
 214     return xp->trust;
 215 }
 216
 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.
 224      */
 225     flags |= X509_TRUST_DO_SS_COMPAT | X509_TRUST_OK_ANY_EKU;
 226     return obj_trust(trust->arg1, x, flags);
 227 }
 228
 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
 240 static int trust_compat(X509_TRUST *trust, X509 *x, int flags)
 241 {
 242     /* Call for side-effect of computing hash and caching extensions */
 243     X509_check_purpose(x, -1, 0);
 244     if ((flags & X509_TRUST_NO_SS_COMPAT) == 0 && x->ex_flags & EXFLAG_SS)
 245         return X509_TRUST_TRUSTED;
 246     else
 247         return X509_TRUST_UNTRUSTED;
 248 }
 249
 250 static int obj_trust(int id, X509 *x, int flags)
 251 {
 252     X509_CERT_AUX *ax = x->aux;
 253     int i;
 254
 255     if (ax && ax->reject) {
 256         for (i = 0; i < sk_ASN1_OBJECT_num(ax->reject); i++) {
 257             ASN1_OBJECT *obj = sk_ASN1_OBJECT_value(ax->reject, i);
 258             int nid = OBJ_obj2nid(obj);
 259
 260             if (nid == id || (nid == NID_anyExtendedKeyUsage &&
 261                 (flags & X509_TRUST_OK_ANY_EKU)))
 262                 return X509_TRUST_REJECTED;
 263         }
 264     }
 265
 266     if (ax && ax->trust) {
 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 &&
 272                 (flags & X509_TRUST_OK_ANY_EKU)))
 273                 return X509_TRUST_TRUSTED;
 274         }
 275         /*
 276          * Reject when explicit trust EKU are set and none match.
 277          *
 278          * Returning untrusted is enough for for full chains that end in
 279          * self-signed roots, because when explicit trust is specified it
 280          * suppresses the default blanket trust of self-signed objects.
 281          *
 282          * But for partial chains, this is not enough, because absent a similar
 283          * trust-self-signed policy, non matching EKUs are indistinguishable
 284          * from lack of EKU constraints.
 285          *
 286          * Therefore, failure to match any trusted purpose must trigger an
 287          * explicit reject.
 288          */
 289         return X509_TRUST_REJECTED;
 290     }
 291
 292     if ((flags & X509_TRUST_DO_SS_COMPAT) == 0)
 293         return X509_TRUST_UNTRUSTED;
 294
 295     /*
 296      * Not rejected, and there is no list of accepted uses, try compat.
 297      */
 298     return trust_compat(NULL, x, flags);
 299 }