qemu/crypto/hash.c

   1 /*
   2  * QEMU Crypto hash algorithms
   3  *
   4  * Copyright (c) 2015 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "crypto/hash.h"
  22
  23 #ifdef CONFIG_GNUTLS_HASH
  24 #include <gnutls/gnutls.h>
  25 #include <gnutls/crypto.h>
  26
  27 static int qcrypto_hash_alg_map[QCRYPTO_HASH_ALG_LAST] = {
  28     [QCRYPTO_HASH_ALG_MD5] = GNUTLS_DIG_MD5,
  29     [QCRYPTO_HASH_ALG_SHA1] = GNUTLS_DIG_SHA1,
  30     [QCRYPTO_HASH_ALG_SHA256] = GNUTLS_DIG_SHA256,
  31 };
  32
  33 gboolean qcrypto_hash_supports(QCryptoHashAlgorithm alg)
  34 {
  35     if (alg < G_N_ELEMENTS(qcrypto_hash_alg_map)) {
  36         return true;
  37     }
  38     return false;
  39 }
  40
  41 int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
  42                         const struct iovec *iov,
  43                         size_t niov,
  44                         uint8_t **result,
  45                         size_t *resultlen,
  46                         Error **errp)
  47 {
  48     int i, ret;
  49     gnutls_hash_hd_t dig;
  50
  51     if (alg >= G_N_ELEMENTS(qcrypto_hash_alg_map)) {
  52         error_setg(errp,
  53                    "Unknown hash algorithm %d",
  54                    alg);
  55         return -1;
  56     }
  57
  58     ret = gnutls_hash_init(&dig, qcrypto_hash_alg_map[alg]);
  59
  60     if (ret < 0) {
  61         error_setg(errp,
  62                    "Unable to initialize hash algorithm: %s",
  63                    gnutls_strerror(ret));
  64         return -1;
  65     }
  66
  67     for (i = 0; i < niov; i++) {
  68         ret = gnutls_hash(dig, iov[i].iov_base, iov[i].iov_len);
  69         if (ret < 0) {
  70             error_setg(errp,
  71                        "Unable process hash data: %s",
  72                        gnutls_strerror(ret));
  73             goto error;
  74         }
  75     }
  76
  77     ret = gnutls_hash_get_len(qcrypto_hash_alg_map[alg]);
  78     if (ret <= 0) {
  79         error_setg(errp,
  80                    "Unable to get hash length: %s",
  81                    gnutls_strerror(ret));
  82         goto error;
  83     }
  84     if (*resultlen == 0) {
  85         *resultlen = ret;
  86         *result = g_new0(uint8_t, *resultlen);
  87     } else if (*resultlen != ret) {
  88         error_setg(errp,
  89                    "Result buffer size %zu is smaller than hash %d",
  90                    *resultlen, ret);
  91         goto error;
  92     }
  93
  94     gnutls_hash_deinit(dig, *result);
  95     return 0;
  96
  97  error:
  98     gnutls_hash_deinit(dig, NULL);
  99     return -1;
 100 }
 101
 102 #else /* ! CONFIG_GNUTLS_HASH */
 103
 104 gboolean qcrypto_hash_supports(QCryptoHashAlgorithm alg G_GNUC_UNUSED)
 105 {
 106     return false;
 107 }
 108
 109 int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
 110                         const struct iovec *iov G_GNUC_UNUSED,
 111                         size_t niov G_GNUC_UNUSED,
 112                         uint8_t **result G_GNUC_UNUSED,
 113                         size_t *resultlen G_GNUC_UNUSED,
 114                         Error **errp)
 115 {
 116     error_setg(errp,
 117                "Hash algorithm %d not supported without GNUTLS",
 118                alg);
 119     return -1;
 120 }
 121
 122 #endif /* ! CONFIG_GNUTLS_HASH */
 123
 124 int qcrypto_hash_bytes(QCryptoHashAlgorithm alg,
 125                        const char *buf,
 126                        size_t len,
 127                        uint8_t **result,
 128                        size_t *resultlen,
 129                        Error **errp)
 130 {
 131     struct iovec iov = { .iov_base = (char *)buf,
 132                          .iov_len = len };
 133     return qcrypto_hash_bytesv(alg, &iov, 1, result, resultlen, errp);
 134 }
 135
 136 static const char hex[] = "0123456789abcdef";
 137
 138 int qcrypto_hash_digestv(QCryptoHashAlgorithm alg,
 139                          const struct iovec *iov,
 140                          size_t niov,
 141                          char **digest,
 142                          Error **errp)
 143 {
 144     uint8_t *result = NULL;
 145     size_t resultlen = 0;
 146     size_t i;
 147
 148     if (qcrypto_hash_bytesv(alg, iov, niov, &result, &resultlen, errp) < 0) {
 149         return -1;
 150     }
 151
 152     *digest = g_new0(char, (resultlen * 2) + 1);
 153     for (i = 0 ; i < resultlen ; i++) {
 154         (*digest)[(i * 2)] = hex[(result[i] >> 4) & 0xf];
 155         (*digest)[(i * 2) + 1] = hex[result[i] & 0xf];
 156     }
 157     (*digest)[resultlen * 2] = '\0';
 158     g_free(result);
 159     return 0;
 160 }
 161
 162 int qcrypto_hash_digest(QCryptoHashAlgorithm alg,
 163                         const char *buf,
 164                         size_t len,
 165                         char **digest,
 166                         Error **errp)
 167 {
 168     struct iovec iov = { .iov_base = (char *)buf, .iov_len = len };
 169
 170     return qcrypto_hash_digestv(alg, &iov, 1, digest, errp);
 171 }
 172
 173 int qcrypto_hash_base64v(QCryptoHashAlgorithm alg,
 174                          const struct iovec *iov,
 175                          size_t niov,
 176                          char **base64,
 177                          Error **errp)
 178 {
 179     uint8_t *result = NULL;
 180     size_t resultlen = 0;
 181
 182     if (qcrypto_hash_bytesv(alg, iov, niov, &result, &resultlen, errp) < 0) {
 183         return -1;
 184     }
 185
 186     *base64 = g_base64_encode(result, resultlen);
 187     g_free(result);
 188     return 0;
 189 }
 190
 191 int qcrypto_hash_base64(QCryptoHashAlgorithm alg,
 192                         const char *buf,
 193                         size_t len,
 194                         char **base64,
 195                         Error **errp)
 196 {
 197     struct iovec iov = { .iov_base = (char *)buf, .iov_len = len };
 198
 199     return qcrypto_hash_base64v(alg, &iov, 1, base64, errp);
 200 }