lib/libcrypto/asn1/a_verify.c

   1 /* $OpenBSD: a_verify.c,v 1.23 2017/01/29 17:49:22 beck Exp $ */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 #include <sys/types.h>
  60
  61 #include <stdio.h>
  62 #include <string.h>
  63 #include <time.h>
  64
  65 #include <openssl/bn.h>
  66 #include <openssl/buffer.h>
  67 #include <openssl/err.h>
  68 #include <openssl/evp.h>
  69 #include <openssl/objects.h>
  70 #include <openssl/x509.h>
  71
  72 #include "asn1_locl.h"
  73
  74 int
  75 ASN1_item_verify(const ASN1_ITEM *it, X509_ALGOR *a,
  76     ASN1_BIT_STRING *signature, void *asn, EVP_PKEY *pkey)
  77 {
  78         EVP_MD_CTX ctx;
  79         unsigned char *buf_in = NULL;
  80         int ret = -1, inl;
  81
  82         int mdnid, pknid;
  83
  84         if (!pkey) {
  85                 ASN1error(ERR_R_PASSED_NULL_PARAMETER);
  86                 return -1;
  87         }
  88
  89         if (signature->type == V_ASN1_BIT_STRING && signature->flags & 0x7)
  90         {
  91                 ASN1error(ASN1_R_INVALID_BIT_STRING_BITS_LEFT);
  92                 return -1;
  93         }
  94
  95         EVP_MD_CTX_init(&ctx);
  96
  97         /* Convert signature OID into digest and public key OIDs */
  98         if (!OBJ_find_sigid_algs(OBJ_obj2nid(a->algorithm), &mdnid, &pknid)) {
  99                 ASN1error(ASN1_R_UNKNOWN_SIGNATURE_ALGORITHM);
 100                 goto err;
 101         }
 102         if (mdnid == NID_undef) {
 103                 if (!pkey->ameth || !pkey->ameth->item_verify) {
 104                         ASN1error(ASN1_R_UNKNOWN_SIGNATURE_ALGORITHM);
 105                         goto err;
 106                 }
 107                 ret = pkey->ameth->item_verify(&ctx, it, asn, a,
 108                     signature, pkey);
 109                 /* Return value of 2 means carry on, anything else means we
 110                  * exit straight away: either a fatal error of the underlying
 111                  * verification routine handles all verification.
 112                  */
 113                 if (ret != 2)
 114                         goto err;
 115                 ret = -1;
 116         } else {
 117                 const EVP_MD *type;
 118                 type = EVP_get_digestbynid(mdnid);
 119                 if (type == NULL) {
 120                         ASN1error(ASN1_R_UNKNOWN_MESSAGE_DIGEST_ALGORITHM);
 121                         goto err;
 122                 }
 123
 124                 /* Check public key OID matches public key type */
 125                 if (EVP_PKEY_type(pknid) != pkey->ameth->pkey_id) {
 126                         ASN1error(ASN1_R_WRONG_PUBLIC_KEY_TYPE);
 127                         goto err;
 128                 }
 129
 130                 if (!EVP_DigestVerifyInit(&ctx, NULL, type, NULL, pkey)) {
 131                         ASN1error(ERR_R_EVP_LIB);
 132                         ret = 0;
 133                         goto err;
 134                 }
 135
 136         }
 137
 138         inl = ASN1_item_i2d(asn, &buf_in, it);
 139
 140         if (buf_in == NULL) {
 141                 ASN1error(ERR_R_MALLOC_FAILURE);
 142                 goto err;
 143         }
 144
 145         if (!EVP_DigestVerifyUpdate(&ctx, buf_in, inl)) {
 146                 ASN1error(ERR_R_EVP_LIB);
 147                 ret = 0;
 148                 goto err;
 149         }
 150
 151         explicit_bzero(buf_in, (unsigned int)inl);
 152         free(buf_in);
 153
 154         if (EVP_DigestVerifyFinal(&ctx, signature->data,
 155             (size_t)signature->length) <= 0) {
 156                 ASN1error(ERR_R_EVP_LIB);
 157                 ret = 0;
 158                 goto err;
 159         }
 160         /* we don't need to zero the 'ctx' because we just checked
 161          * public information */
 162         /* memset(&ctx,0,sizeof(ctx)); */
 163         ret = 1;
 164
 165 err:
 166         EVP_MD_CTX_cleanup(&ctx);
 167         return (ret);
 168 }