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 struct scatterlist; 10 struct blkcipher_desc; 11 12 #define XTS_BLOCK_SIZE 16 13 14 struct xts_crypt_req { 15 le128 *tbuf; 16 unsigned int tbuflen; 17 18 void *tweak_ctx; 19 void (*tweak_fn)(void *ctx, u8* dst, const u8* src); 20 void *crypt_ctx; 21 void (*crypt_fn)(void *ctx, u8 *blks, unsigned int nbytes); 22 }; 23 24 #define XTS_TWEAK_CAST(x) ((void (*)(void *, u8*, const u8*))(x)) 25 26 int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *dst, 27 struct scatterlist *src, unsigned int nbytes, 28 struct xts_crypt_req *req); 29 30 static inline int xts_check_key(struct crypto_tfm *tfm, 31 const u8 *key, unsigned int keylen) 32 { 33 u32 *flags = &tfm->crt_flags; 34 35 /* 36 * key consists of keys of equal size concatenated, therefore 37 * the length must be even. 38 */ 39 if (keylen % 2) { 40 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 41 return -EINVAL; 42 } 43 44 /* ensure that the AES and tweak key are not identical */ 45 if (fips_enabled && 46 !crypto_memneq(key, key + (keylen / 2), keylen / 2)) { 47 *flags |= CRYPTO_TFM_RES_WEAK_KEY; 48 return -EINVAL; 49 } 50 51 return 0; 52 } 53 54 static inline int xts_verify_key(struct crypto_skcipher *tfm, 55 const u8 *key, unsigned int keylen) 56 { 57 /* 58 * key consists of keys of equal size concatenated, therefore 59 * the length must be even. 60 */ 61 if (keylen % 2) { 62 crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); 63 return -EINVAL; 64 } 65 66 /* ensure that the AES and tweak key are not identical */ 67 if ((fips_enabled || crypto_skcipher_get_flags(tfm) & 68 CRYPTO_TFM_REQ_WEAK_KEY) && 69 !crypto_memneq(key, key + (keylen / 2), keylen / 2)) { 70 crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY); 71 return -EINVAL; 72 } 73 74 return 0; 75 } 76 77 #endif /* _CRYPTO_XTS_H */ 78