crypto: xts - drop xts_check_key()

xts_check_key() is obsoleted by xts_verify_key(). Over time XTS crypto
drivers adopted the newer xts_verify_key() variant, but xts_check_key()
is still used by a number of drivers. Switch drivers to use the newer
xts_verify_key() and make a couple of cleanups. This allows us to drop
xts_check_key() completely and avoid redundancy.

Signed-off-by: Vladis Dronov <[e-mail]>
Reviewed-by: Eric Biggers <[e-mail]>
Reviewed-by: Nicolai Stange <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

arch/s390/crypto/paes_s390.c

···
 		return rc;
 
 	/*
-	 * xts_check_key verifies the key length is not odd and makes
+	 * xts_verify_key verifies the key length is not odd and makes
 	 * sure that the two keys are not the same. This can be done
 	 * on the two protected keys as well
 	 */

drivers/crypto/atmel-aes.c

···
 	struct atmel_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 	int err;
 
-	err = xts_check_key(crypto_skcipher_tfm(tfm), key, keylen);
+	err = xts_verify_key(tfm, key, keylen);
 	if (err)
 		return err;
 

drivers/crypto/axis/artpec6_crypto.c

···
 		crypto_skcipher_ctx(cipher);
 	int ret;
 
-	ret = xts_check_key(&cipher->base, key, keylen);
+	ret = xts_verify_key(cipher, key, keylen);
 	if (ret)
 		return ret;
 

drivers/crypto/cavium/cpt/cptvf_algs.c

···
 static int cvm_xts_setkey(struct crypto_skcipher *cipher, const u8 *key,
 		   u32 keylen)
 {
-	struct crypto_tfm *tfm = crypto_skcipher_tfm(cipher);
-	struct cvm_enc_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct cvm_enc_ctx *ctx = crypto_skcipher_ctx(cipher);
 	int err;
 	const u8 *key1 = key;
 	const u8 *key2 = key + (keylen / 2);
 
-	err = xts_check_key(tfm, key, keylen);
+	err = xts_verify_key(cipher, key, keylen);
 	if (err)
 		return err;
 	ctx->key_len = keylen;
···
 static int cvm_setkey(struct crypto_skcipher *cipher, const u8 *key,
 		      u32 keylen, u8 cipher_type)
 {
-	struct crypto_tfm *tfm = crypto_skcipher_tfm(cipher);
-	struct cvm_enc_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct cvm_enc_ctx *ctx = crypto_skcipher_ctx(cipher);
 
 	ctx->cipher_type = cipher_type;
 	if (!cvm_validate_keylen(ctx, keylen)) {

drivers/crypto/cavium/nitrox/nitrox_skcipher.c

···
 static int nitrox_aes_xts_setkey(struct crypto_skcipher *cipher,
 				 const u8 *key, unsigned int keylen)
 {
-	struct crypto_tfm *tfm = crypto_skcipher_tfm(cipher);
-	struct nitrox_crypto_ctx *nctx = crypto_tfm_ctx(tfm);
+	struct nitrox_crypto_ctx *nctx = crypto_skcipher_ctx(cipher);
 	struct flexi_crypto_context *fctx;
 	int aes_keylen, ret;
 
-	ret = xts_check_key(tfm, key, keylen);
+	ret = xts_verify_key(cipher, key, keylen);
 	if (ret)
 		return ret;
 
···
 static int nitrox_aes_ctr_rfc3686_setkey(struct crypto_skcipher *cipher,
 					 const u8 *key, unsigned int keylen)
 {
-	struct crypto_tfm *tfm = crypto_skcipher_tfm(cipher);
-	struct nitrox_crypto_ctx *nctx = crypto_tfm_ctx(tfm);
+	struct nitrox_crypto_ctx *nctx = crypto_skcipher_ctx(cipher);
 	struct flexi_crypto_context *fctx;
 	int aes_keylen;
 

drivers/crypto/ccree/cc_cipher.c

···
 	}
 
 	if (ctx_p->cipher_mode == DRV_CIPHER_XTS &&
-	    xts_check_key(tfm, key, keylen)) {
+	    xts_verify_key(sktfm, key, keylen)) {
 		dev_dbg(dev, "weak XTS key");
 		return -EINVAL;
 	}

drivers/crypto/marvell/octeontx/otx_cptvf_algs.c

···
 	const u8 *key1 = key;
 	int ret;
 
-	ret = xts_check_key(crypto_skcipher_tfm(tfm), key, keylen);
+	ret = xts_verify_key(tfm, key, keylen);
 	if (ret)
 		return ret;
 	ctx->key_len = keylen;

drivers/crypto/marvell/octeontx2/otx2_cptvf_algs.c

···
 	const u8 *key1 = key;
 	int ret;
 
-	ret = xts_check_key(crypto_skcipher_tfm(tfm), key, keylen);
+	ret = xts_verify_key(tfm, key, keylen);
 	if (ret)
 		return ret;
 	ctx->key_len = keylen;

include/crypto/xts.h

···
 
 #define XTS_BLOCK_SIZE 16
 
-static inline int xts_check_key(struct crypto_tfm *tfm,
-				const u8 *key, unsigned int keylen)
-{
-	/*
-	 * key consists of keys of equal size concatenated, therefore
-	 * the length must be even.
-	 */
-	if (keylen % 2)
-		return -EINVAL;
-
-	/* ensure that the AES and tweak key are not identical */
-	if (fips_enabled && !crypto_memneq(key, key + (keylen / 2), keylen / 2))
-		return -EINVAL;
-
-	return 0;
-}
-
 static inline int xts_verify_key(struct crypto_skcipher *tfm,
 				 const u8 *key, unsigned int keylen)
 {
···
 	if (fips_enabled && keylen != 32 && keylen != 64)
 		return -EINVAL;
 
-	/* ensure that the AES and tweak key are not identical */
+	/*
+	 * Ensure that the AES and tweak key are not identical when
+	 * in FIPS mode or the FORBID_WEAK_KEYS flag is set.
+	 */
 	if ((fips_enabled || (crypto_skcipher_get_flags(tfm) &
 			      CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)) &&
 	    !crypto_memneq(key, key + (keylen / 2), keylen / 2))