LXR qemu/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
  23static 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
  33typedef struct QCryptoHmacGnutls QCryptoHmacGnutls;
  34struct QCryptoHmacGnutls {
  35    gnutls_hmac_hd_t handle;
  36};
  37
  38bool 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
  55void *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
  81error:
  82    g_free(ctx);
  83    return NULL;
  84}
  85
  86static void
  87qcrypto_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
  97static int
  98qcrypto_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
 136QCryptoHmacDriver qcrypto_hmac_lib_driver = {
 137    .hmac_bytesv = qcrypto_gnutls_hmac_bytesv,
 138    .hmac_free = qcrypto_gnutls_hmac_ctx_free,
 139};
 140