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 (file)
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -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
@@ -449,6 +452,111 @@ err:
        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

diff --git a/crypto/internal.h b/crypto/internal.h
index 8ef72d7..3c19a27 100644 (file)
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -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);

diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index 5fb6d86..986db68 100644 (file)
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -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 {

diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index ea52cd9..ffaaa41 100644 (file)
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -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);