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[CRYPTO] api: Added crypto_alloc_base

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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: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Herbert Xu 2006-07-30 11:53:01 +10:00
parent 65b75c36f4
commit 6d7d684d63
2 changed files with 63 additions and 11 deletions
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60
crypto/api.c
View file

@ -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;

14
include/linux/crypto.h
View file

@ -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);
/*