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 "qemu/osdep.h"
  22 #include "qapi/error.h"
  23 #include "crypto/hash.h"
  24
  25 #ifdef CONFIG_GNUTLS_HASH
  26 #include <gnutls/gnutls.h>
  27 #include <gnutls/crypto.h>
  28 #endif
  29
  30
  31 static size_t qcrypto_hash_alg_size[QCRYPTO_HASH_ALG__MAX] = {
  32     [QCRYPTO_HASH_ALG_MD5] = 16,
  33     [QCRYPTO_HASH_ALG_SHA1] = 20,
  34     [QCRYPTO_HASH_ALG_SHA256] = 32,
  35 };
  36
  37 size_t qcrypto_hash_digest_len(QCryptoHashAlgorithm alg)
  38 {
  39     if (alg >= G_N_ELEMENTS(qcrypto_hash_alg_size)) {
  40         return 0;
  41     }
  42     return qcrypto_hash_alg_size[alg];
  43 }
  44
  45
  46 #ifdef CONFIG_GNUTLS_HASH
  47 static int qcrypto_hash_alg_map[QCRYPTO_HASH_ALG__MAX] = {
  48     [QCRYPTO_HASH_ALG_MD5] = GNUTLS_DIG_MD5,
  49     [QCRYPTO_HASH_ALG_SHA1] = GNUTLS_DIG_SHA1,
  50     [QCRYPTO_HASH_ALG_SHA256] = GNUTLS_DIG_SHA256,
  51 };
  52
  53 gboolean qcrypto_hash_supports(QCryptoHashAlgorithm alg)
  54 {
  55     if (alg < G_N_ELEMENTS(qcrypto_hash_alg_map)) {
  56         return true;
  57     }
  58     return false;
  59 }
  60
  61
  62 int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
  63                         const struct iovec *iov,
  64                         size_t niov,
  65                         uint8_t **result,
  66                         size_t *resultlen,
  67                         Error **errp)
  68 {
  69     int i, ret;
  70     gnutls_hash_hd_t dig;
  71
  72     if (alg >= G_N_ELEMENTS(qcrypto_hash_alg_map)) {
  73         error_setg(errp,
  74                    "Unknown hash algorithm %d",
  75                    alg);
  76         return -1;
  77     }
  78
  79     ret = gnutls_hash_init(&dig, qcrypto_hash_alg_map[alg]);
  80
  81     if (ret < 0) {
  82         error_setg(errp,
  83                    "Unable to initialize hash algorithm: %s",
  84                    gnutls_strerror(ret));
  85         return -1;
  86     }
  87
  88     for (i = 0; i < niov; i++) {
  89         ret = gnutls_hash(dig, iov[i].iov_base, iov[i].iov_len);
  90         if (ret < 0) {
  91             error_setg(errp,
  92                        "Unable process hash data: %s",
  93                        gnutls_strerror(ret));
  94             goto error;
  95         }
  96     }
  97
  98     ret = gnutls_hash_get_len(qcrypto_hash_alg_map[alg]);
  99     if (ret <= 0) {
 100         error_setg(errp,
 101                    "Unable to get hash length: %s",
 102                    gnutls_strerror(ret));
 103         goto error;
 104     }
 105     if (*resultlen == 0) {
 106         *resultlen = ret;
 107         *result = g_new0(uint8_t, *resultlen);
 108     } else if (*resultlen != ret) {
 109         error_setg(errp,
 110                    "Result buffer size %zu is smaller than hash %d",
 111                    *resultlen, ret);
 112         goto error;
 113     }
 114
 115     gnutls_hash_deinit(dig, *result);
 116     return 0;
 117
 118  error:
 119     gnutls_hash_deinit(dig, NULL);
 120     return -1;
 121 }
 122
 123 #else /* ! CONFIG_GNUTLS_HASH */
 124
 125 gboolean qcrypto_hash_supports(QCryptoHashAlgorithm alg G_GNUC_UNUSED)
 126 {
 127     return false;
 128 }
 129
 130 int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
 131                         const struct iovec *iov G_GNUC_UNUSED,
 132                         size_t niov G_GNUC_UNUSED,
 133                         uint8_t **result G_GNUC_UNUSED,
 134                         size_t *resultlen G_GNUC_UNUSED,
 135                         Error **errp)
 136 {
 137     error_setg(errp,
 138                "Hash algorithm %d not supported without GNUTLS",
 139                alg);
 140     return -1;
 141 }
 142
 143 #endif /* ! CONFIG_GNUTLS_HASH */
 144
 145 int qcrypto_hash_bytes(QCryptoHashAlgorithm alg,
 146                        const char *buf,
 147                        size_t len,
 148                        uint8_t **result,
 149                        size_t *resultlen,
 150                        Error **errp)
 151 {
 152     struct iovec iov = { .iov_base = (char *)buf,
 153                          .iov_len = len };
 154     return qcrypto_hash_bytesv(alg, &iov, 1, result, resultlen, errp);
 155 }
 156
 157 static const char hex[] = "0123456789abcdef";
 158
 159 int qcrypto_hash_digestv(QCryptoHashAlgorithm alg,
 160                          const struct iovec *iov,
 161                          size_t niov,
 162                          char **digest,
 163                          Error **errp)
 164 {
 165     uint8_t *result = NULL;
 166     size_t resultlen = 0;
 167     size_t i;
 168
 169     if (qcrypto_hash_bytesv(alg, iov, niov, &result, &resultlen, errp) < 0) {
 170         return -1;
 171     }
 172
 173     *digest = g_new0(char, (resultlen * 2) + 1);
 174     for (i = 0 ; i < resultlen ; i++) {
 175         (*digest)[(i * 2)] = hex[(result[i] >> 4) & 0xf];
 176         (*digest)[(i * 2) + 1] = hex[result[i] & 0xf];
 177     }
 178     (*digest)[resultlen * 2] = '\0';
 179     g_free(result);
 180     return 0;
 181 }
 182
 183 int qcrypto_hash_digest(QCryptoHashAlgorithm alg,
 184                         const char *buf,
 185                         size_t len,
 186                         char **digest,
 187                         Error **errp)
 188 {
 189     struct iovec iov = { .iov_base = (char *)buf, .iov_len = len };
 190
 191     return qcrypto_hash_digestv(alg, &iov, 1, digest, errp);
 192 }
 193
 194 int qcrypto_hash_base64v(QCryptoHashAlgorithm alg,
 195                          const struct iovec *iov,
 196                          size_t niov,
 197                          char **base64,
 198                          Error **errp)
 199 {
 200     uint8_t *result = NULL;
 201     size_t resultlen = 0;
 202
 203     if (qcrypto_hash_bytesv(alg, iov, niov, &result, &resultlen, errp) < 0) {
 204         return -1;
 205     }
 206
 207     *base64 = g_base64_encode(result, resultlen);
 208     g_free(result);
 209     return 0;
 210 }
 211
 212 int qcrypto_hash_base64(QCryptoHashAlgorithm alg,
 213                         const char *buf,
 214                         size_t len,
 215                         char **base64,
 216                         Error **errp)
 217 {
 218     struct iovec iov = { .iov_base = (char *)buf, .iov_len = len };
 219
 220     return qcrypto_hash_base64v(alg, &iov, 1, base64, errp);
 221 }