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include/crypto/xts.h 1.81 KB
81f7e3824   Eric Lee   Initial Release, ...
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  /* SPDX-License-Identifier: GPL-2.0 */
  #ifndef _CRYPTO_XTS_H
  #define _CRYPTO_XTS_H
  
  #include <crypto/b128ops.h>
  #include <crypto/internal/skcipher.h>
  #include <linux/fips.h>
  
  struct scatterlist;
  struct blkcipher_desc;
  
  #define XTS_BLOCK_SIZE 16
  
  struct xts_crypt_req {
  	le128 *tbuf;
  	unsigned int tbuflen;
  
  	void *tweak_ctx;
  	void (*tweak_fn)(void *ctx, u8* dst, const u8* src);
  	void *crypt_ctx;
  	void (*crypt_fn)(void *ctx, u8 *blks, unsigned int nbytes);
  };
  
  #define XTS_TWEAK_CAST(x) ((void (*)(void *, u8*, const u8*))(x))
  
  int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
  	      struct scatterlist *src, unsigned int nbytes,
  	      struct xts_crypt_req *req);
  
  static inline int xts_check_key(struct crypto_tfm *tfm,
  				const u8 *key, unsigned int keylen)
  {
  	u32 *flags = &tfm->crt_flags;
  
  	/*
  	 * key consists of keys of equal size concatenated, therefore
  	 * the length must be even.
  	 */
  	if (keylen % 2) {
  		*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  		return -EINVAL;
  	}
  
  	/* ensure that the AES and tweak key are not identical */
  	if (fips_enabled &&
  	    !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
  		*flags |= CRYPTO_TFM_RES_WEAK_KEY;
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static inline int xts_verify_key(struct crypto_skcipher *tfm,
  				 const u8 *key, unsigned int keylen)
  {
  	/*
  	 * key consists of keys of equal size concatenated, therefore
  	 * the length must be even.
  	 */
  	if (keylen % 2) {
  		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
  		return -EINVAL;
  	}
  
  	/* ensure that the AES and tweak key are not identical */
  	if ((fips_enabled || crypto_skcipher_get_flags(tfm) &
  			     CRYPTO_TFM_REQ_WEAK_KEY) &&
  	    !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
  		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  #endif  /* _CRYPTO_XTS_H */