include/crypto/xts.h

   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_check_key(struct crypto_tfm *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         /* ensure that the AES and tweak key are not identical */
  22         if (fips_enabled && !crypto_memneq(key, key + (keylen / 2), keylen / 2))
  23                 return -EINVAL;
  24
  25         return 0;
  26 }
  27
  28 static inline int xts_verify_key(struct crypto_skcipher *tfm,
  29                                  const u8 *key, unsigned int keylen)
  30 {
  31         /*
  32          * key consists of keys of equal size concatenated, therefore
  33          * the length must be even.
  34          */
  35         if (keylen % 2)
  36                 return -EINVAL;
  37
  38         /* ensure that the AES and tweak key are not identical */
  39         if ((fips_enabled || (crypto_skcipher_get_flags(tfm) &
  40                               CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)) &&
  41             !crypto_memneq(key, key + (keylen / 2), keylen / 2))
  42                 return -EINVAL;
  43
  44         return 0;
  45 }
  46
  47 #endif  /* _CRYPTO_XTS_H */