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 "qemu/osdep.h"
  22 #include "crypto/hash.h"
  23
  24 #ifdef CONFIG_GNUTLS_HASH
  25 #include <gnutls/gnutls.h>
  26 #include <gnutls/crypto.h>
  27 #endif
  28
  29
  30 static size_t qcrypto_hash_alg_size[QCRYPTO_HASH_ALG__MAX] = {
  31     [QCRYPTO_HASH_ALG_MD5] = 16,
  32     [QCRYPTO_HASH_ALG_SHA1] = 20,
  33     [QCRYPTO_HASH_ALG_SHA256] = 32,
  34 };
  35
  36 size_t qcrypto_hash_digest_len(QCryptoHashAlgorithm alg)
  37 {
  38     if (alg >= G_N_ELEMENTS(qcrypto_hash_alg_size)) {
  39         return 0;
  40     }
  41     return qcrypto_hash_alg_size[alg];
  42 }
  43
  44
  45 #ifdef CONFIG_GNUTLS_HASH
  46 static int qcrypto_hash_alg_map[QCRYPTO_HASH_ALG__MAX] = {
  47     [QCRYPTO_HASH_ALG_MD5] = GNUTLS_DIG_MD5,
  48     [QCRYPTO_HASH_ALG_SHA1] = GNUTLS_DIG_SHA1,
  49     [QCRYPTO_HASH_ALG_SHA256] = GNUTLS_DIG_SHA256,
  50 };
  51
  52 gboolean qcrypto_hash_supports(QCryptoHashAlgorithm alg)
  53 {
  54     if (alg < G_N_ELEMENTS(qcrypto_hash_alg_map)) {
  55         return true;
  56     }
  57     return false;
  58 }
  59
  60
  61 int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
  62                         const struct iovec *iov,
  63                         size_t niov,
  64                         uint8_t **result,
  65                         size_t *resultlen,
  66                         Error **errp)
  67 {
  68     int i, ret;
  69     gnutls_hash_hd_t dig;
  70
  71     if (alg >= G_N_ELEMENTS(qcrypto_hash_alg_map)) {
  72         error_setg(errp,
  73                    "Unknown hash algorithm %d",
  74                    alg);
  75         return -1;
  76     }
  77
  78     ret = gnutls_hash_init(&dig, qcrypto_hash_alg_map[alg]);
  79
  80     if (ret < 0) {
  81         error_setg(errp,
  82                    "Unable to initialize hash algorithm: %s",
  83                    gnutls_strerror(ret));
  84         return -1;
  85     }
  86
  87     for (i = 0; i < niov; i++) {
  88         ret = gnutls_hash(dig, iov[i].iov_base, iov[i].iov_len);
  89         if (ret < 0) {
  90             error_setg(errp,
  91                        "Unable process hash data: %s",
  92                        gnutls_strerror(ret));
  93             goto error;
  94         }
  95     }
  96
  97     ret = gnutls_hash_get_len(qcrypto_hash_alg_map[alg]);
  98     if (ret <= 0) {
  99         error_setg(errp,
 100                    "Unable to get hash length: %s",
 101                    gnutls_strerror(ret));
 102         goto error;
 103     }
 104     if (*resultlen == 0) {
 105         *resultlen = ret;
 106         *result = g_new0(uint8_t, *resultlen);
 107     } else if (*resultlen != ret) {
 108         error_setg(errp,
 109                    "Result buffer size %zu is smaller than hash %d",
 110                    *resultlen, ret);
 111         goto error;
 112     }
 113
 114     gnutls_hash_deinit(dig, *result);
 115     return 0;
 116
 117  error:
 118     gnutls_hash_deinit(dig, NULL);
 119     return -1;
 120 }
 121
 122 #else /* ! CONFIG_GNUTLS_HASH */
 123
 124 gboolean qcrypto_hash_supports(QCryptoHashAlgorithm alg G_GNUC_UNUSED)
 125 {
 126     return false;
 127 }
 128
 129 int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
 130                         const struct iovec *iov G_GNUC_UNUSED,
 131                         size_t niov G_GNUC_UNUSED,
 132                         uint8_t **result G_GNUC_UNUSED,
 133                         size_t *resultlen G_GNUC_UNUSED,
 134                         Error **errp)
 135 {
 136     error_setg(errp,
 137                "Hash algorithm %d not supported without GNUTLS",
 138                alg);
 139     return -1;
 140 }
 141
 142 #endif /* ! CONFIG_GNUTLS_HASH */
 143
 144 int qcrypto_hash_bytes(QCryptoHashAlgorithm alg,
 145                        const char *buf,
 146                        size_t len,
 147                        uint8_t **result,
 148                        size_t *resultlen,
 149                        Error **errp)
 150 {
 151     struct iovec iov = { .iov_base = (char *)buf,
 152                          .iov_len = len };
 153     return qcrypto_hash_bytesv(alg, &iov, 1, result, resultlen, errp);
 154 }
 155
 156 static const char hex[] = "0123456789abcdef";
 157
 158 int qcrypto_hash_digestv(QCryptoHashAlgorithm alg,
 159                          const struct iovec *iov,
 160                          size_t niov,
 161                          char **digest,
 162                          Error **errp)
 163 {
 164     uint8_t *result = NULL;
 165     size_t resultlen = 0;
 166     size_t i;
 167
 168     if (qcrypto_hash_bytesv(alg, iov, niov, &result, &resultlen, errp) < 0) {
 169         return -1;
 170     }
 171
 172     *digest = g_new0(char, (resultlen * 2) + 1);
 173     for (i = 0 ; i < resultlen ; i++) {
 174         (*digest)[(i * 2)] = hex[(result[i] >> 4) & 0xf];
 175         (*digest)[(i * 2) + 1] = hex[result[i] & 0xf];
 176     }
 177     (*digest)[resultlen * 2] = '\0';
 178     g_free(result);
 179     return 0;
 180 }
 181
 182 int qcrypto_hash_digest(QCryptoHashAlgorithm alg,
 183                         const char *buf,
 184                         size_t len,
 185                         char **digest,
 186                         Error **errp)
 187 {
 188     struct iovec iov = { .iov_base = (char *)buf, .iov_len = len };
 189
 190     return qcrypto_hash_digestv(alg, &iov, 1, digest, errp);
 191 }
 192
 193 int qcrypto_hash_base64v(QCryptoHashAlgorithm alg,
 194                          const struct iovec *iov,
 195                          size_t niov,
 196                          char **base64,
 197                          Error **errp)
 198 {
 199     uint8_t *result = NULL;
 200     size_t resultlen = 0;
 201
 202     if (qcrypto_hash_bytesv(alg, iov, niov, &result, &resultlen, errp) < 0) {
 203         return -1;
 204     }
 205
 206     *base64 = g_base64_encode(result, resultlen);
 207     g_free(result);
 208     return 0;
 209 }
 210
 211 int qcrypto_hash_base64(QCryptoHashAlgorithm alg,
 212                         const char *buf,
 213                         size_t len,
 214                         char **base64,
 215                         Error **errp)
 216 {
 217     struct iovec iov = { .iov_base = (char *)buf, .iov_len = len };
 218
 219     return qcrypto_hash_base64v(alg, &iov, 1, base64, errp);
 220 }