crypto/hmac-gnutls.c

   1 /*
   2  * QEMU Crypto hmac algorithms
   3  *
   4  * Copyright (c) 2021 Red Hat, Inc.
   5  *
   6  * Derived from hmac-gcrypt.c:
   7  *
   8  *   Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
   9  *
  10  * This work is licensed under the terms of the GNU GPL, version 2 or
  11  * (at your option) any later version.  See the COPYING file in the
  12  * top-level directory.
  13  *
  14  */
  15
  16 #include "qemu/osdep.h"
  17 #include <gnutls/crypto.h>
  18
  19 #include "qapi/error.h"
  20 #include "crypto/hmac.h"
  21 #include "hmacpriv.h"
  22
  23 static int qcrypto_hmac_alg_map[QCRYPTO_HASH_ALG__MAX] = {
  24     [QCRYPTO_HASH_ALG_MD5] = GNUTLS_MAC_MD5,
  25     [QCRYPTO_HASH_ALG_SHA1] = GNUTLS_MAC_SHA1,
  26     [QCRYPTO_HASH_ALG_SHA224] = GNUTLS_MAC_SHA224,
  27     [QCRYPTO_HASH_ALG_SHA256] = GNUTLS_MAC_SHA256,
  28     [QCRYPTO_HASH_ALG_SHA384] = GNUTLS_MAC_SHA384,
  29     [QCRYPTO_HASH_ALG_SHA512] = GNUTLS_MAC_SHA512,
  30     [QCRYPTO_HASH_ALG_RIPEMD160] = GNUTLS_MAC_RMD160,
  31 };
  32
  33 typedef struct QCryptoHmacGnutls QCryptoHmacGnutls;
  34 struct QCryptoHmacGnutls {
  35     gnutls_hmac_hd_t handle;
  36 };
  37
  38 bool qcrypto_hmac_supports(QCryptoHashAlgorithm alg)
  39 {
  40     size_t i;
  41     const gnutls_digest_algorithm_t *algs;
  42     if (alg >= G_N_ELEMENTS(qcrypto_hmac_alg_map) ||
  43         qcrypto_hmac_alg_map[alg] == GNUTLS_DIG_UNKNOWN) {
  44         return false;
  45     }
  46     algs = gnutls_digest_list();
  47     for (i = 0; algs[i] != GNUTLS_DIG_UNKNOWN; i++) {
  48         if (algs[i] == qcrypto_hmac_alg_map[alg]) {
  49             return true;
  50         }
  51     }
  52     return false;
  53 }
  54
  55 void *qcrypto_hmac_ctx_new(QCryptoHashAlgorithm alg,
  56                            const uint8_t *key, size_t nkey,
  57                            Error **errp)
  58 {
  59     QCryptoHmacGnutls *ctx;
  60     int err;
  61
  62     if (!qcrypto_hmac_supports(alg)) {
  63         error_setg(errp, "Unsupported hmac algorithm %s",
  64                    QCryptoHashAlgorithm_str(alg));
  65         return NULL;
  66     }
  67
  68     ctx = g_new0(QCryptoHmacGnutls, 1);
  69
  70     err = gnutls_hmac_init(&ctx->handle,
  71                            qcrypto_hmac_alg_map[alg],
  72                            (const void *)key, nkey);
  73     if (err != 0) {
  74         error_setg(errp, "Cannot initialize hmac: %s",
  75                    gnutls_strerror(err));
  76         goto error;
  77     }
  78
  79     return ctx;
  80
  81 error:
  82     g_free(ctx);
  83     return NULL;
  84 }
  85
  86 static void
  87 qcrypto_gnutls_hmac_ctx_free(QCryptoHmac *hmac)
  88 {
  89     QCryptoHmacGnutls *ctx;
  90
  91     ctx = hmac->opaque;
  92     gnutls_hmac_deinit(ctx->handle, NULL);
  93
  94     g_free(ctx);
  95 }
  96
  97 static int
  98 qcrypto_gnutls_hmac_bytesv(QCryptoHmac *hmac,
  99                            const struct iovec *iov,
 100                            size_t niov,
 101                            uint8_t **result,
 102                            size_t *resultlen,
 103                            Error **errp)
 104 {
 105     QCryptoHmacGnutls *ctx;
 106     uint32_t ret;
 107     int i;
 108
 109     ctx = hmac->opaque;
 110
 111     for (i = 0; i < niov; i++) {
 112         gnutls_hmac(ctx->handle, iov[i].iov_base, iov[i].iov_len);
 113     }
 114
 115     ret = gnutls_hmac_get_len(qcrypto_hmac_alg_map[hmac->alg]);
 116     if (ret <= 0) {
 117         error_setg(errp, "Unable to get hmac length: %s",
 118                    gnutls_strerror(ret));
 119         return -1;
 120     }
 121
 122     if (*resultlen == 0) {
 123         *resultlen = ret;
 124         *result = g_new0(uint8_t, *resultlen);
 125     } else if (*resultlen != ret) {
 126         error_setg(errp, "Result buffer size %zu is smaller than hmac %d",
 127                    *resultlen, ret);
 128         return -1;
 129     }
 130
 131     gnutls_hmac_output(ctx->handle, *result);
 132
 133     return 0;
 134 }
 135
 136 QCryptoHmacDriver qcrypto_hmac_lib_driver = {
 137     .hmac_bytesv = qcrypto_gnutls_hmac_bytesv,
 138     .hmac_free = qcrypto_gnutls_hmac_ctx_free,
 139 };