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	be128 *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 */