Commit 6d7d684d authored by Herbert Xu's avatar Herbert Xu
Browse files

[CRYPTO] api: Added crypto_alloc_base 



Up until now all crypto transforms have been of the same type, struct
crypto_tfm, regardless of whether they are ciphers, digests, or other
types.  As a result of that, we check the types at run-time before
each crypto operation.

This is rather cumbersome.  We could instead use different C types for
each crypto type to ensure that the correct types are used at compile
time.  That is, we would have crypto_cipher/crypto_digest instead of
just crypto_tfm.  The appropriate type would then be required for the
actual operations such as crypto_digest_digest.

Now that we have the type/mask fields when looking up algorithms, it
is easy to request for an algorithm of the precise type that the user
wants.  However, crypto_alloc_tfm currently does not expose these new
attributes.

This patch introduces the function crypto_alloc_base which will carry
these new parameters.  It will be renamed to crypto_alloc_tfm once
all existing users have been converted.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 65b75c36

crypto/api.c

+60 −0
Original line number Diff line number Diff line
@@ -372,6 +372,66 @@ struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags) 
	return tfm;

}



/*

 *	crypto_alloc_base - Locate algorithm and allocate transform

 *	@alg_name: Name of algorithm

 *	@type: Type of algorithm

 *	@mask: Mask for type comparison

 *

 *	crypto_alloc_base() will first attempt to locate an already loaded

 *	algorithm.  If that fails and the kernel supports dynamically loadable

 *	modules, it will then attempt to load a module of the same name or

 *	alias.  If that fails it will send a query to any loaded crypto manager

 *	to construct an algorithm on the fly.  A refcount is grabbed on the

 *	algorithm which is then associated with the new transform.

 *

 *	The returned transform is of a non-determinate type.  Most people

 *	should use one of the more specific allocation functions such as

 *	crypto_alloc_blkcipher.

 *

 *	In case of error the return value is an error pointer.

 */

struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)

{

	struct crypto_tfm *tfm;

	int err;



	for (;;) {

		struct crypto_alg *alg;



		alg = crypto_alg_mod_lookup(alg_name, type, mask);

		err = PTR_ERR(alg);

		tfm = ERR_PTR(err);

		if (IS_ERR(alg))

			goto err;



		tfm = __crypto_alloc_tfm(alg, 0);

		if (!IS_ERR(tfm))

			break;



		crypto_mod_put(alg);

		err = PTR_ERR(tfm);



err:

		if (err != -EAGAIN)

			break;

		if (signal_pending(current)) {

			err = -EINTR;

			break;

		}

	};



	return tfm;

}

EXPORT_SYMBOL_GPL(crypto_alloc_base);

 

/*

 *	crypto_free_tfm - Free crypto transform

 *	@tfm: Transform to free

 *

 *	crypto_free_tfm() frees up the transform and any associated resources,

 *	then drops the refcount on the associated algorithm.

 */

void crypto_free_tfm(struct crypto_tfm *tfm)

{

	struct crypto_alg *alg;

include/linux/crypto.h

+3 −11
Original line number Diff line number Diff line
@@ -194,8 +194,8 @@ static inline int crypto_alg_available(const char *name, u32 flags) 


/*

 * Transforms: user-instantiated objects which encapsulate algorithms

 * and core processing logic.  Managed via crypto_alloc_tfm() and

 * crypto_free_tfm(), as well as the various helpers below.

 * and core processing logic.  Managed via crypto_alloc_*() and

 * crypto_free_*(), as well as the various helpers below.

 */



struct cipher_tfm {
@@ -278,16 +278,8 @@ struct crypto_attr_alg { 
 * Transform user interface.

 */

 

/*

 * crypto_alloc_tfm() will first attempt to locate an already loaded algorithm.

 * If that fails and the kernel supports dynamically loadable modules, it

 * will then attempt to load a module of the same name or alias.  A refcount

 * is grabbed on the algorithm which is then associated with the new transform.

 *

 * crypto_free_tfm() frees up the transform and any associated resources,

 * then drops the refcount on the associated algorithm.

 */

struct crypto_tfm *crypto_alloc_tfm(const char *alg_name, u32 tfm_flags);

struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask);

void crypto_free_tfm(struct crypto_tfm *tfm);



/*

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