LXR linux/include/crypto/xts.h

   1#ifndef _CRYPTO_XTS_H
   2#define _CRYPTO_XTS_H
   3
   4#include <crypto/b128ops.h>
   5#include <crypto/internal/skcipher.h>
   6#include <linux/fips.h>
   7
   8struct scatterlist;
   9struct blkcipher_desc;
  10
  11#define XTS_BLOCK_SIZE 16
  12
  13struct xts_crypt_req {
  14        le128 *tbuf;
  15        unsigned int tbuflen;
  16
  17        void *tweak_ctx;
  18        void (*tweak_fn)(void *ctx, u8* dst, const u8* src);
  19        void *crypt_ctx;
  20        void (*crypt_fn)(void *ctx, u8 *blks, unsigned int nbytes);
  21};
  22
  23#define XTS_TWEAK_CAST(x) ((void (*)(void *, u8*, const u8*))(x))
  24
  25int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
  26              struct scatterlist *src, unsigned int nbytes,
  27              struct xts_crypt_req *req);
  28
  29static inline int xts_check_key(struct crypto_tfm *tfm,
  30                                const u8 *key, unsigned int keylen)
  31{
  32        u32 *flags = &tfm->crt_flags;
  33
  34        /*
  35         * key consists of keys of equal size concatenated, therefore
  36         * the length must be even.
  37         */
  38        if (keylen % 2) {
  39                *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  40                return -EINVAL;
  41        }
  42
  43        /* ensure that the AES and tweak key are not identical */
  44        if (fips_enabled &&
  45            !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
  46                *flags |= CRYPTO_TFM_RES_WEAK_KEY;
  47                return -EINVAL;
  48        }
  49
  50        return 0;
  51}
  52
  53static inline int xts_verify_key(struct crypto_skcipher *tfm,
  54                                 const u8 *key, unsigned int keylen)
  55{
  56        /*
  57         * key consists of keys of equal size concatenated, therefore
  58         * the length must be even.
  59         */
  60        if (keylen % 2) {
  61                crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
  62                return -EINVAL;
  63        }
  64
  65        /* ensure that the AES and tweak key are not identical */
  66        if ((fips_enabled || crypto_skcipher_get_flags(tfm) &
  67                             CRYPTO_TFM_REQ_WEAK_KEY) &&
  68            !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
  69                crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
  70                return -EINVAL;
  71        }
  72
  73        return 0;
  74}
  75
  76#endif  /* _CRYPTO_XTS_H */
  77