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/*
* Scatterlist Cryptographic API.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
* Copyright (c) 2002 David S. Miller (davem@redhat.com)
* Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
*
* Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
* and Nettle, by Niels Möller.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "internal.h"
LIST_HEAD(crypto_alg_list);
EXPORT_SYMBOL_GPL(crypto_alg_list);
DECLARE_RWSEM(crypto_alg_sem);
EXPORT_SYMBOL_GPL(crypto_alg_sem);
static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
{
atomic_inc(&alg->cra_refcnt);
return alg;
}
static inline void crypto_alg_put(struct crypto_alg *alg)
{
if (atomic_dec_and_test(&alg->cra_refcnt) && alg->cra_destroy)
alg->cra_destroy(alg);
}
static struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
{
return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
}
static void crypto_mod_put(struct crypto_alg *alg)
{
crypto_alg_put(alg);
module_put(alg->cra_module);
}
static struct crypto_alg *crypto_alg_lookup(const char *name)
{
struct crypto_alg *q, *alg = NULL;
int best = -1;
if (!name)
return NULL;
down_read(&crypto_alg_sem);
list_for_each_entry(q, &crypto_alg_list, cra_list) {
int exact, fuzzy;
exact = !strcmp(q->cra_driver_name, name);
fuzzy = !strcmp(q->cra_name, name);
if (!exact && !(fuzzy && q->cra_priority > best))
continue;
if (unlikely(!crypto_mod_get(q)))
continue;
best = q->cra_priority;
if (alg)
crypto_mod_put(alg);
alg = q;
if (exact)
break;
}
up_read(&crypto_alg_sem);
return alg;
}
/* A far more intelligent version of this is planned. For now, just
* try an exact match on the name of the algorithm. */
static inline struct crypto_alg *crypto_alg_mod_lookup(const char *name)
{
return try_then_request_module(crypto_alg_lookup(name), name);
}
static int crypto_init_flags(struct crypto_tfm *tfm, u32 flags)
{
tfm->crt_flags = flags & CRYPTO_TFM_REQ_MASK;
flags &= ~CRYPTO_TFM_REQ_MASK;
switch (crypto_tfm_alg_type(tfm)) {
case CRYPTO_ALG_TYPE_CIPHER:
return crypto_init_cipher_flags(tfm, flags);
case CRYPTO_ALG_TYPE_DIGEST:
return crypto_init_digest_flags(tfm, flags);
case CRYPTO_ALG_TYPE_COMPRESS:
return crypto_init_compress_flags(tfm, flags);
default:
break;
}
BUG();
return -EINVAL;
}
static int crypto_init_ops(struct crypto_tfm *tfm)
{
switch (crypto_tfm_alg_type(tfm)) {
case CRYPTO_ALG_TYPE_CIPHER:
return crypto_init_cipher_ops(tfm);
case CRYPTO_ALG_TYPE_DIGEST:
return crypto_init_digest_ops(tfm);
case CRYPTO_ALG_TYPE_COMPRESS:
return crypto_init_compress_ops(tfm);
default:
break;
}
BUG();
return -EINVAL;
}
static void crypto_exit_ops(struct crypto_tfm *tfm)
{
switch (crypto_tfm_alg_type(tfm)) {
case CRYPTO_ALG_TYPE_CIPHER:
crypto_exit_cipher_ops(tfm);
break;
case CRYPTO_ALG_TYPE_DIGEST:
crypto_exit_digest_ops(tfm);
break;
case CRYPTO_ALG_TYPE_COMPRESS:
crypto_exit_compress_ops(tfm);
break;
default:
BUG();
}
}
static unsigned int crypto_ctxsize(struct crypto_alg *alg, int flags)
{
unsigned int len;
switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
default:
BUG();
case CRYPTO_ALG_TYPE_CIPHER:
len = crypto_cipher_ctxsize(alg, flags);
break;
case CRYPTO_ALG_TYPE_DIGEST:
len = crypto_digest_ctxsize(alg, flags);
break;
case CRYPTO_ALG_TYPE_COMPRESS:
len = crypto_compress_ctxsize(alg, flags);
break;
}
return len + (alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1));
}
struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
{
struct crypto_tfm *tfm = NULL;
struct crypto_alg *alg;
unsigned int tfm_size;
alg = crypto_alg_mod_lookup(name);
if (alg == NULL)
goto out;
tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, flags);
tfm = kzalloc(tfm_size, GFP_KERNEL);
if (tfm == NULL)
goto out_put;
tfm->__crt_alg = alg;
if (crypto_init_flags(tfm, flags))
goto out_free_tfm;
if (crypto_init_ops(tfm))
goto out_free_tfm;
if (alg->cra_init && alg->cra_init(tfm))
goto cra_init_failed;
goto out;
cra_init_failed:
crypto_exit_ops(tfm);
out_free_tfm:
kfree(tfm);
tfm = NULL;
out_put:
crypto_mod_put(alg);
out:
return tfm;
}
void crypto_free_tfm(struct crypto_tfm *tfm)
{
struct crypto_alg *alg;
int size;
if (unlikely(!tfm))
return;
alg = tfm->__crt_alg;
size = sizeof(*tfm) + alg->cra_ctxsize;
if (alg->cra_exit)
alg->cra_exit(tfm);
crypto_exit_ops(tfm);
crypto_mod_put(alg);
memset(tfm, 0, size);
kfree(tfm);
}
int crypto_alg_available(const char *name, u32 flags)
{
int ret = 0;
struct crypto_alg *alg = crypto_alg_mod_lookup(name);
if (alg) {
crypto_mod_put(alg);
ret = 1;
}
return ret;
}
EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
EXPORT_SYMBOL_GPL(crypto_free_tfm);
EXPORT_SYMBOL_GPL(crypto_alg_available);
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