Commit 7b0bac64 authored by Herbert Xu's avatar Herbert Xu

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: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 4a779486
......@@ -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
......
......@@ -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);
......
......@@ -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 {
......
......@@ -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);
......
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