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/* 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
#define XTS_TWEAK_CAST(x) ((void (*)(void *, u8*, const u8*))(x))
static inline int xts_check_key(struct crypto_tfm *tfm,
const u8 *key, unsigned int keylen)
{
u32 *flags = &tfm->crt_flags;
/*
* key consists of keys of equal size concatenated, therefore
* the length must be even.
*/
if (keylen % 2) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
/* ensure that the AES and tweak key are not identical */
if (fips_enabled &&
!crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
*flags |= CRYPTO_TFM_RES_WEAK_KEY;
return -EINVAL;
}
return 0;
}
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) {
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
return -EINVAL;
}
/* ensure that the AES and tweak key are not identical */
if ((fips_enabled || (crypto_skcipher_get_flags(tfm) &
CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)) &&
!crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
return -EINVAL;
}
return 0;
}
#endif /* _CRYPTO_XTS_H */
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