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