1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _CRYPTO_XTS_H
 3#define _CRYPTO_XTS_H
 4
 5#include <crypto/b128ops.h>
 6#include <crypto/internal/skcipher.h>
 7#include <linux/fips.h>
 8
 9#define XTS_BLOCK_SIZE 16
10
11static inline int xts_check_key(struct crypto_tfm *tfm,
12				const u8 *key, unsigned int keylen)
13{
14	/*
15	 * key consists of keys of equal size concatenated, therefore
16	 * the length must be even.
17	 */
18	if (keylen % 2)
19		return -EINVAL;
20
21	/* ensure that the AES and tweak key are not identical */
22	if (fips_enabled && !crypto_memneq(key, key + (keylen / 2), keylen / 2))
23		return -EINVAL;
24
25	return 0;
26}
27
28static inline int xts_verify_key(struct crypto_skcipher *tfm,
29				 const u8 *key, unsigned int keylen)
30{
31	/*
32	 * key consists of keys of equal size concatenated, therefore
33	 * the length must be even.
34	 */
35	if (keylen % 2)
36		return -EINVAL;
37
38	/* ensure that the AES and tweak key are not identical */
39	if ((fips_enabled || (crypto_skcipher_get_flags(tfm) &
40			      CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)) &&
41	    !crypto_memneq(key, key + (keylen / 2), keylen / 2))
42		return -EINVAL;
43
44	return 0;
45}
46
47#endif  /* _CRYPTO_XTS_H */