LXR linux/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
   9struct scatterlist;
  10struct blkcipher_desc;
  11
  12#define XTS_BLOCK_SIZE 16
  13
  14struct 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
  26int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
  27              struct scatterlist *src, unsigned int nbytes,
  28              struct xts_crypt_req *req);
  29
  30static 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
  54static 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