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 static inline int xts_verify_key(struct crypto_skcipher *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 /*
22 * In FIPS mode only a combined key length of either 256 or
23 * 512 bits is allowed, c.f. FIPS 140-3 IG C.I.
24 */
25 if (fips_enabled && keylen != 32 && keylen != 64)
26 return -EINVAL;
27
28 /*
29 * Ensure that the AES and tweak key are not identical when
30 * in FIPS mode or the FORBID_WEAK_KEYS flag is set.
31 */
32 if ((fips_enabled || (crypto_skcipher_get_flags(tfm) &
33 CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)) &&
34 !crypto_memneq(key, key + (keylen / 2), keylen / 2))
35 return -EINVAL;
36
37 return 0;
38 }
39
40 #endif /* _CRYPTO_XTS_H */
41
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