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