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 u32 *flags = &tfm->crt_flags;
15
16 /*
17 * key consists of keys of equal size concatenated, therefore
18 * the length must be even.
19 */
20 if (keylen % 2) {
21 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
22 return -EINVAL;
23 }
24
25 /* ensure that the AES and tweak key are not identical */
26 if (fips_enabled &&
27 !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
28 *flags |= CRYPTO_TFM_RES_WEAK_KEY;
29 return -EINVAL;
30 }
31
32 return 0;
33 }
34
xts_verify_key(struct crypto_skcipher * tfm,const u8 * key,unsigned int keylen)35 static inline int xts_verify_key(struct crypto_skcipher *tfm,
36 const u8 *key, unsigned int keylen)
37 {
38 /*
39 * key consists of keys of equal size concatenated, therefore
40 * the length must be even.
41 */
42 if (keylen % 2) {
43 crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
44 return -EINVAL;
45 }
46
47 /* ensure that the AES and tweak key are not identical */
48 if ((fips_enabled || (crypto_skcipher_get_flags(tfm) &
49 CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)) &&
50 !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
51 crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
52 return -EINVAL;
53 }
54
55 return 0;
56 }
57
58 #endif /* _CRYPTO_XTS_H */
59