[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>
diff --git a/crypto/api.c b/crypto/api.c
index 1e4692a..bc4b790 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -372,6 +372,66 @@
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;
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 530dc4b..6847ab0 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -194,8 +194,8 @@
/*
* 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 @@
* 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);
/*