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
 9struct scatterlist;
10struct blkcipher_desc;
11
12#define XTS_BLOCK_SIZE 16
13
14struct 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
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
54#endif  /* _CRYPTO_XTS_H */