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: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/api.c b/crypto/api.c
index cbaaf34..9975a7b 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -403,6 +403,9 @@
* @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
@@ -449,6 +452,111 @@
return ERR_PTR(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