Commit ed3630b8 authored by Herbert Xu's avatar Herbert Xu
Browse files

crypto: hash - Add crypto_clone_ahash/shash 



This patch adds the helpers crypto_clone_ahash and crypto_clone_shash.
They are the hash-specific counterparts of crypto_clone_tfm.

This allows code paths that cannot otherwise allocate a hash tfm
object to do so.  Once a new tfm has been obtained its key could
then be changed without impacting other users.

Note that only algorithms that implement clone_tfm can be cloned.
However, all keyless hashes can be cloned by simply reusing the
tfm object.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: default avatarSimon Horman <simon.horman@corigine.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 3c3a24cb

crypto/ahash.c

+51 −0
Original line number Diff line number Diff line
@@ -543,6 +543,57 @@ int crypto_has_ahash(const char *alg_name, u32 type, u32 mask) 
}

EXPORT_SYMBOL_GPL(crypto_has_ahash);



struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)

{

	struct hash_alg_common *halg = crypto_hash_alg_common(hash);

	struct crypto_tfm *tfm = crypto_ahash_tfm(hash);

	struct crypto_ahash *nhash;

	struct ahash_alg *alg;

	int err;



	if (!crypto_hash_alg_has_setkey(halg)) {

		tfm = crypto_tfm_get(tfm);

		if (IS_ERR(tfm))

			return ERR_CAST(tfm);



		return hash;

	}



	nhash = crypto_clone_tfm(&crypto_ahash_type, tfm);



	if (IS_ERR(nhash))

		return nhash;



	nhash->init = hash->init;

	nhash->update = hash->update;

	nhash->final = hash->final;

	nhash->finup = hash->finup;

	nhash->digest = hash->digest;

	nhash->export = hash->export;

	nhash->import = hash->import;

	nhash->setkey = hash->setkey;

	nhash->reqsize = hash->reqsize;



	if (tfm->__crt_alg->cra_type != &crypto_ahash_type)

		return crypto_clone_shash_ops_async(nhash, hash);



	err = -ENOSYS;

	alg = crypto_ahash_alg(hash);

	if (!alg->clone_tfm)

		goto out_free_nhash;



	err = alg->clone_tfm(nhash, hash);

	if (err)

		goto out_free_nhash;



	return nhash;



out_free_nhash:

	crypto_free_ahash(nhash);

	return ERR_PTR(err);

}

EXPORT_SYMBOL_GPL(crypto_clone_ahash);



static int ahash_prepare_alg(struct ahash_alg *alg)

{

	struct crypto_alg *base = &alg->halg.base;

crypto/hash.h

+4 −0
Original line number Diff line number Diff line
@@ -31,6 +31,10 @@ static inline int crypto_hash_report_stat(struct sk_buff *skb, 
	return nla_put(skb, CRYPTOCFGA_STAT_HASH, sizeof(rhash), &rhash);

}



int crypto_init_shash_ops_async(struct crypto_tfm *tfm);

struct crypto_ahash *crypto_clone_shash_ops_async(struct crypto_ahash *nhash,

						  struct crypto_ahash *hash);



int hash_prepare_alg(struct hash_alg_common *alg);



#endif	/* _LOCAL_CRYPTO_HASH_H */

crypto/shash.c

+52 −0
Original line number Diff line number Diff line
@@ -445,6 +445,24 @@ int crypto_init_shash_ops_async(struct crypto_tfm *tfm) 
	return 0;

}



struct crypto_ahash *crypto_clone_shash_ops_async(struct crypto_ahash *nhash,

						  struct crypto_ahash *hash)

{

	struct crypto_shash **nctx = crypto_ahash_ctx(nhash);

	struct crypto_shash **ctx = crypto_ahash_ctx(hash);

	struct crypto_shash *shash;



	shash = crypto_clone_shash(*ctx);

	if (IS_ERR(shash)) {

		crypto_free_ahash(nhash);

		return ERR_CAST(shash);

	}



	*nctx = shash;



	return nhash;

}



static void crypto_shash_exit_tfm(struct crypto_tfm *tfm)

{

	struct crypto_shash *hash = __crypto_shash_cast(tfm);
@@ -564,6 +582,40 @@ int crypto_has_shash(const char *alg_name, u32 type, u32 mask) 
}

EXPORT_SYMBOL_GPL(crypto_has_shash);



struct crypto_shash *crypto_clone_shash(struct crypto_shash *hash)

{

	struct crypto_tfm *tfm = crypto_shash_tfm(hash);

	struct shash_alg *alg = crypto_shash_alg(hash);

	struct crypto_shash *nhash;

	int err;



	if (!crypto_shash_alg_has_setkey(alg)) {

		tfm = crypto_tfm_get(tfm);

		if (IS_ERR(tfm))

			return ERR_CAST(tfm);



		return hash;

	}



	if (!alg->clone_tfm)

		return ERR_PTR(-ENOSYS);



	nhash = crypto_clone_tfm(&crypto_shash_type, tfm);

	if (IS_ERR(nhash))

		return nhash;



	nhash->descsize = hash->descsize;



	err = alg->clone_tfm(nhash, hash);

	if (err) {

		crypto_free_shash(nhash);

		return ERR_PTR(err);

	}



	return nhash;

}

EXPORT_SYMBOL_GPL(crypto_clone_shash);



int hash_prepare_alg(struct hash_alg_common *alg)

{

	struct crypto_istat_hash *istat = hash_get_stat(alg);

include/crypto/hash.h

+8 −0
Original line number Diff line number Diff line
@@ -152,6 +152,7 @@ struct ahash_request { 
 * @exit_tfm: Deinitialize the cryptographic transformation object.

 *	      This is a counterpart to @init_tfm, used to remove

 *	      various changes set in @init_tfm.

 * @clone_tfm: Copy transform into new object, may allocate memory.

 * @halg: see struct hash_alg_common

 */

struct ahash_alg {
@@ -166,6 +167,7 @@ struct ahash_alg { 
		      unsigned int keylen);

	int (*init_tfm)(struct crypto_ahash *tfm);

	void (*exit_tfm)(struct crypto_ahash *tfm);

	int (*clone_tfm)(struct crypto_ahash *dst, struct crypto_ahash *src);



	struct hash_alg_common halg;

};
@@ -209,6 +211,7 @@ struct shash_desc { 
 * @exit_tfm: Deinitialize the cryptographic transformation object.

 *	      This is a counterpart to @init_tfm, used to remove

 *	      various changes set in @init_tfm.

 * @clone_tfm: Copy transform into new object, may allocate memory.

 * @digestsize: see struct ahash_alg

 * @statesize: see struct ahash_alg

 * @descsize: Size of the operational state for the message digest. This state
@@ -234,6 +237,7 @@ struct shash_alg { 
		      unsigned int keylen);

	int (*init_tfm)(struct crypto_shash *tfm);

	void (*exit_tfm)(struct crypto_shash *tfm);

	int (*clone_tfm)(struct crypto_shash *dst, struct crypto_shash *src);



	unsigned int descsize;
@@ -297,6 +301,8 @@ static inline struct crypto_ahash *__crypto_ahash_cast(struct crypto_tfm *tfm) 
struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,

					u32 mask);



struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *tfm);



static inline struct crypto_tfm *crypto_ahash_tfm(struct crypto_ahash *tfm)

{

	return &tfm->base;
@@ -761,6 +767,8 @@ static inline void ahash_request_set_crypt(struct ahash_request *req, 
struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,

					u32 mask);



struct crypto_shash *crypto_clone_shash(struct crypto_shash *tfm);



int crypto_has_shash(const char *alg_name, u32 type, u32 mask);



static inline struct crypto_tfm *crypto_shash_tfm(struct crypto_shash *tfm)

include/crypto/internal/hash.h

+0 −2
Original line number Diff line number Diff line
@@ -133,8 +133,6 @@ int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc); 
int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc);

int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc);



int crypto_init_shash_ops_async(struct crypto_tfm *tfm);



static inline void *crypto_ahash_ctx(struct crypto_ahash *tfm)

{

	return crypto_tfm_ctx(crypto_ahash_tfm(tfm));