/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _CRYPTO_XTS_H
#define _CRYPTO_XTS_H
#include <crypto/b128ops.h>
#include <crypto/internal/skcipher.h>
#include <linux/fips.h>
#define XTS_BLOCK_SIZE 16
static inline int xts_verify_key(struct crypto_skcipher *tfm,
const u8 *key, unsigned int keylen)
{
/*
* key consists of keys of equal size concatenated, therefore
* the length must be even.
*/
if (keylen % 2)
return -EINVAL;
/*
* In FIPS mode only a combined key length of either 256 or
* 512 bits is allowed, c.f. FIPS 140-3 IG C.I.
*/
if (fips_enabled && keylen != 32 && keylen != 64)
return -EINVAL;
/*
* Ensure that the AES and tweak key are not identical when
* in FIPS mode or the FORBID_WEAK_KEYS flag is set.
*/
if ((fips_enabled || (crypto_skcipher_get_flags(tfm) &
CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)) &&
!crypto_memneq(key, key + (keylen / 2), keylen / 2))
return -EINVAL;
return 0;
}
#endif /* _CRYPTO_XTS_H */