qemu/crypto/hmac-gnutls.c
Daniel P. Berrangé 678307b605 crypto: add gnutls hmac provider
This adds support for using gnutls as a provider of the crypto
hmac APIs.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2021-07-14 14:15:52 +01:00

140 lines
3.5 KiB
C

/*
* QEMU Crypto hmac algorithms
*
* Copyright (c) 2021 Red Hat, Inc.
*
* Derived from hmac-gcrypt.c:
*
* Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* (at your option) any later version. See the COPYING file in the
* top-level directory.
*
*/
#include "qemu/osdep.h"
#include <gnutls/crypto.h>
#include "qapi/error.h"
#include "crypto/hmac.h"
#include "hmacpriv.h"
static int qcrypto_hmac_alg_map[QCRYPTO_HASH_ALG__MAX] = {
[QCRYPTO_HASH_ALG_MD5] = GNUTLS_MAC_MD5,
[QCRYPTO_HASH_ALG_SHA1] = GNUTLS_MAC_SHA1,
[QCRYPTO_HASH_ALG_SHA224] = GNUTLS_MAC_SHA224,
[QCRYPTO_HASH_ALG_SHA256] = GNUTLS_MAC_SHA256,
[QCRYPTO_HASH_ALG_SHA384] = GNUTLS_MAC_SHA384,
[QCRYPTO_HASH_ALG_SHA512] = GNUTLS_MAC_SHA512,
[QCRYPTO_HASH_ALG_RIPEMD160] = GNUTLS_MAC_RMD160,
};
typedef struct QCryptoHmacGnutls QCryptoHmacGnutls;
struct QCryptoHmacGnutls {
gnutls_hmac_hd_t handle;
};
bool qcrypto_hmac_supports(QCryptoHashAlgorithm alg)
{
size_t i;
const gnutls_digest_algorithm_t *algs;
if (alg >= G_N_ELEMENTS(qcrypto_hmac_alg_map) ||
qcrypto_hmac_alg_map[alg] == GNUTLS_DIG_UNKNOWN) {
return false;
}
algs = gnutls_digest_list();
for (i = 0; algs[i] != GNUTLS_DIG_UNKNOWN; i++) {
if (algs[i] == qcrypto_hmac_alg_map[alg]) {
return true;
}
}
return false;
}
void *qcrypto_hmac_ctx_new(QCryptoHashAlgorithm alg,
const uint8_t *key, size_t nkey,
Error **errp)
{
QCryptoHmacGnutls *ctx;
int err;
if (!qcrypto_hmac_supports(alg)) {
error_setg(errp, "Unsupported hmac algorithm %s",
QCryptoHashAlgorithm_str(alg));
return NULL;
}
ctx = g_new0(QCryptoHmacGnutls, 1);
err = gnutls_hmac_init(&ctx->handle,
qcrypto_hmac_alg_map[alg],
(const void *)key, nkey);
if (err != 0) {
error_setg(errp, "Cannot initialize hmac: %s",
gnutls_strerror(err));
goto error;
}
return ctx;
error:
g_free(ctx);
return NULL;
}
static void
qcrypto_gnutls_hmac_ctx_free(QCryptoHmac *hmac)
{
QCryptoHmacGnutls *ctx;
ctx = hmac->opaque;
gnutls_hmac_deinit(ctx->handle, NULL);
g_free(ctx);
}
static int
qcrypto_gnutls_hmac_bytesv(QCryptoHmac *hmac,
const struct iovec *iov,
size_t niov,
uint8_t **result,
size_t *resultlen,
Error **errp)
{
QCryptoHmacGnutls *ctx;
uint32_t ret;
int i;
ctx = hmac->opaque;
for (i = 0; i < niov; i++) {
gnutls_hmac(ctx->handle, iov[i].iov_base, iov[i].iov_len);
}
ret = gnutls_hmac_get_len(qcrypto_hmac_alg_map[hmac->alg]);
if (ret <= 0) {
error_setg(errp, "Unable to get hmac length: %s",
gnutls_strerror(ret));
return -1;
}
if (*resultlen == 0) {
*resultlen = ret;
*result = g_new0(uint8_t, *resultlen);
} else if (*resultlen != ret) {
error_setg(errp, "Result buffer size %zu is smaller than hmac %d",
*resultlen, ret);
return -1;
}
gnutls_hmac_output(ctx->handle, *result);
return 0;
}
QCryptoHmacDriver qcrypto_hmac_lib_driver = {
.hmac_bytesv = qcrypto_gnutls_hmac_bytesv,
.hmac_free = qcrypto_gnutls_hmac_ctx_free,
};