[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: Herbert Xu <herbert@gondor.apana.org.au>
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crypto/api.c
60
crypto/api.c
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@ -372,6 +372,66 @@ struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
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return tfm;
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}
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/*
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* crypto_alloc_base - Locate algorithm and allocate transform
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* @alg_name: Name of algorithm
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* @type: Type of algorithm
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* @mask: Mask for type comparison
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*
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* crypto_alloc_base() will first attempt to locate an already loaded
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* algorithm. If that fails and the kernel supports dynamically loadable
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* modules, it will then attempt to load a module of the same name or
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* alias. If that fails it will send a query to any loaded crypto manager
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* to construct an algorithm on the fly. A refcount is grabbed on the
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* algorithm which is then associated with the new transform.
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*
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* The returned transform is of a non-determinate type. Most people
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* should use one of the more specific allocation functions such as
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* crypto_alloc_blkcipher.
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*
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* In case of error the return value is an error pointer.
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*/
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struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
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{
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struct crypto_tfm *tfm;
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int err;
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for (;;) {
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struct crypto_alg *alg;
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alg = crypto_alg_mod_lookup(alg_name, type, mask);
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err = PTR_ERR(alg);
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tfm = ERR_PTR(err);
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if (IS_ERR(alg))
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goto err;
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tfm = __crypto_alloc_tfm(alg, 0);
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if (!IS_ERR(tfm))
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break;
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crypto_mod_put(alg);
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err = PTR_ERR(tfm);
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err:
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if (err != -EAGAIN)
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break;
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if (signal_pending(current)) {
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err = -EINTR;
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break;
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}
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};
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return tfm;
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}
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EXPORT_SYMBOL_GPL(crypto_alloc_base);
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/*
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* crypto_free_tfm - Free crypto transform
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* @tfm: Transform to free
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*
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* crypto_free_tfm() frees up the transform and any associated resources,
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* then drops the refcount on the associated algorithm.
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*/
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void crypto_free_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_alg *alg;
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@ -194,8 +194,8 @@ static inline int crypto_alg_available(const char *name, u32 flags)
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/*
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* Transforms: user-instantiated objects which encapsulate algorithms
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* and core processing logic. Managed via crypto_alloc_tfm() and
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* crypto_free_tfm(), as well as the various helpers below.
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* and core processing logic. Managed via crypto_alloc_*() and
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* crypto_free_*(), as well as the various helpers below.
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*/
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struct cipher_tfm {
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@ -278,16 +278,8 @@ struct crypto_attr_alg {
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* Transform user interface.
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*/
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/*
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* crypto_alloc_tfm() will first attempt to locate an already loaded algorithm.
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* If that fails and the kernel supports dynamically loadable modules, it
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* will then attempt to load a module of the same name or alias. A refcount
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* is grabbed on the algorithm which is then associated with the new transform.
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*
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* crypto_free_tfm() frees up the transform and any associated resources,
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* then drops the refcount on the associated algorithm.
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*/
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struct crypto_tfm *crypto_alloc_tfm(const char *alg_name, u32 tfm_flags);
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struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask);
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void crypto_free_tfm(struct crypto_tfm *tfm);
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/*
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