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
xts_check_key(struct crypto_tfm * tfm,const u8 * key,unsigned int keylen)11 static 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
xts_verify_key(struct crypto_skcipher * tfm,const u8 * key,unsigned int keylen)28 static 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 */
48