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
11 #define XTS_TWEAK_CAST(x) ((void (*)(void *, u8*, const u8*))(x))
12
xts_check_key(struct crypto_tfm * tfm,const u8 * key,unsigned int keylen)13 static inline int xts_check_key(struct crypto_tfm *tfm,
14 const u8 *key, unsigned int keylen)
15 {
16 u32 *flags = &tfm->crt_flags;
17
18 /*
19 * key consists of keys of equal size concatenated, therefore
20 * the length must be even.
21 */
22 if (keylen % 2) {
23 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
24 return -EINVAL;
25 }
26
27 /* ensure that the AES and tweak key are not identical */
28 if (fips_enabled &&
29 !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
30 *flags |= CRYPTO_TFM_RES_WEAK_KEY;
31 return -EINVAL;
32 }
33
34 return 0;
35 }
36
xts_verify_key(struct crypto_skcipher * tfm,const u8 * key,unsigned int keylen)37 static inline int xts_verify_key(struct crypto_skcipher *tfm,
38 const u8 *key, unsigned int keylen)
39 {
40 /*
41 * key consists of keys of equal size concatenated, therefore
42 * the length must be even.
43 */
44 if (keylen % 2) {
45 crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
46 return -EINVAL;
47 }
48
49 /* ensure that the AES and tweak key are not identical */
50 if ((fips_enabled || crypto_skcipher_get_flags(tfm) &
51 CRYPTO_TFM_REQ_WEAK_KEY) &&
52 !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
53 crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
54 return -EINVAL;
55 }
56
57 return 0;
58 }
59
60 #endif /* _CRYPTO_XTS_H */
61