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 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 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_FORBID_WEAK_KEYS)) && 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