Commit 7b0bac64 authored by Herbert Xu's avatar Herbert Xu
Browse files

crypto: api - Rebirth of crypto_alloc_tfm 



This patch reintroduces a completely revamped crypto_alloc_tfm.
The biggest change is that we now take two crypto_type objects
when allocating a tfm, a frontend and a backend.  In fact this
simply formalises what we've been doing behind the API's back.

For example, as it stands crypto_alloc_ahash may use an
actual ahash algorithm or a crypto_hash algorithm.  Putting
this in the API allows us to do this much more cleanly.

The existing types will be converted across gradually.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 4a779486

crypto/api.c

+108 −0
Original line number Diff line number Diff line
@@ -403,6 +403,9 @@ EXPORT_SYMBOL_GPL(__crypto_alloc_tfm); 
 *	@type: Type of algorithm

 *	@mask: Mask for type comparison

 *

 *	This function should not be used by new algorithm types.

 *	Plesae use crypto_alloc_tfm instead.

 *

 *	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
@@ -450,6 +453,111 @@ err: 
}

EXPORT_SYMBOL_GPL(crypto_alloc_base);



struct crypto_tfm *crypto_create_tfm(struct crypto_alg *alg,

				     const struct crypto_type *frontend)

{

	char *mem;

	struct crypto_tfm *tfm = NULL;

	unsigned int tfmsize;

	unsigned int total;

	int err = -ENOMEM;



	tfmsize = frontend->tfmsize;

	total = tfmsize + sizeof(*tfm) + frontend->extsize(alg, frontend);



	mem = kzalloc(total, GFP_KERNEL);

	if (mem == NULL)

		goto out_err;



	tfm = (struct crypto_tfm *)(mem + tfmsize);

	tfm->__crt_alg = alg;



	err = frontend->init_tfm(tfm, frontend);

	if (err)

		goto out_free_tfm;



	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))

		goto cra_init_failed;



	goto out;



cra_init_failed:

	crypto_exit_ops(tfm);

out_free_tfm:

	if (err == -EAGAIN)

		crypto_shoot_alg(alg);

	kfree(mem);

out_err:

	tfm = ERR_PTR(err);

out:

	return tfm;

}

EXPORT_SYMBOL_GPL(crypto_create_tfm);



/*

 *	crypto_alloc_tfm - Locate algorithm and allocate transform

 *	@alg_name: Name of algorithm

 *	@frontend: Frontend algorithm type

 *	@type: Type of algorithm

 *	@mask: Mask for type comparison

 *

 *	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.  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_tfm(const char *alg_name,

				    const struct crypto_type *frontend,

				    u32 type, u32 mask)

{

	struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask);

	struct crypto_tfm *tfm;

	int err;



	type &= frontend->maskclear;

	mask &= frontend->maskclear;

	type |= frontend->type;

	mask |= frontend->maskset;



	lookup = frontend->lookup ?: crypto_alg_mod_lookup;



	for (;;) {

		struct crypto_alg *alg;



		alg = lookup(alg_name, type, mask);

		if (IS_ERR(alg)) {

			err = PTR_ERR(alg);

			goto err;

		}



		tfm = crypto_create_tfm(alg, frontend);

		if (!IS_ERR(tfm))

			return tfm;



		crypto_mod_put(alg);

		err = PTR_ERR(tfm);



err:

		if (err != -EAGAIN)

			break;

		if (signal_pending(current)) {

			err = -EINTR;

			break;

		}

	}



	return ERR_PTR(err);

}

EXPORT_SYMBOL_GPL(crypto_alloc_tfm);

 

/*

 *	crypto_free_tfm - Free crypto transform

 *	@tfm: Transform to free

crypto/internal.h

+2 −0
Original line number Diff line number Diff line
@@ -109,6 +109,8 @@ void crypto_alg_tested(const char *name, int err); 
void crypto_shoot_alg(struct crypto_alg *alg);

struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,

				      u32 mask);

struct crypto_tfm *crypto_create_tfm(struct crypto_alg *alg,

				     const struct crypto_type *frontend);



int crypto_register_instance(struct crypto_template *tmpl,

			     struct crypto_instance *inst);

include/crypto/algapi.h

+10 −0
Original line number Diff line number Diff line
@@ -22,8 +22,18 @@ struct seq_file; 


struct crypto_type {

	unsigned int (*ctxsize)(struct crypto_alg *alg, u32 type, u32 mask);

	unsigned int (*extsize)(struct crypto_alg *alg,

				const struct crypto_type *frontend);

	int (*init)(struct crypto_tfm *tfm, u32 type, u32 mask);

	int (*init_tfm)(struct crypto_tfm *tfm,

		        const struct crypto_type *frontend);

	void (*show)(struct seq_file *m, struct crypto_alg *alg);

	struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask);



	unsigned int type;

	unsigned int maskclear;

	unsigned int maskset;

	unsigned int tfmsize;

};



struct crypto_instance {

include/linux/crypto.h

+3 −1
Original line number Diff line number Diff line
@@ -546,7 +546,9 @@ struct crypto_attr_u32 { 
 * Transform user interface.

 */

 

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

struct crypto_tfm *crypto_alloc_tfm(const char *alg_name,

				    const struct crypto_type *frontend,

				    u32 type, u32 mask);

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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