include/crypto/xts.h

   1 #ifndef _CRYPTO_XTS_H
   2 #define _CRYPTO_XTS_H
   3
   4 #include <crypto/b128ops.h>
   5 #include <linux/crypto.h>
   6 #include <crypto/algapi.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         be128 *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 #endif  /* _CRYPTO_XTS_H */