android_kernel_samsung_msm8976/crypto/api.c
Jesper Juhl a61cc44812 [CRYPTO] Add null short circuit to crypto_free_tfm
As far as I'm aware there's a general concensus that functions that are
responsible for freeing resources should be able to cope with being passed
a NULL pointer. This makes sense as it removes the need for all callers to
check for NULL, thus elliminating the bugs that happen when some forget
(safer to just check centrally in the freeing function) and it also makes
for smaller code all over due to the lack of all those NULL checks.
This patch makes it safe to pass the crypto_free_tfm() function a NULL
pointer. Once this patch is applied we can start removing the NULL checks
from the callers.

Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-06 13:54:31 -07:00

281 lines
5.3 KiB
C

/*
* Scatterlist Cryptographic API.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
* Copyright (c) 2002 David S. Miller (davem@redhat.com)
*
* 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/compiler.h>
#include <linux/init.h>
#include <linux/crypto.h>
#include <linux/errno.h>
#include <linux/kmod.h>
#include <linux/rwsem.h>
#include <linux/slab.h>
#include "internal.h"
LIST_HEAD(crypto_alg_list);
DECLARE_RWSEM(crypto_alg_sem);
static inline int crypto_alg_get(struct crypto_alg *alg)
{
return try_module_get(alg->cra_module);
}
static inline void crypto_alg_put(struct crypto_alg *alg)
{
module_put(alg->cra_module);
}
static struct crypto_alg *crypto_alg_lookup(const char *name)
{
struct crypto_alg *q, *alg = NULL;
if (!name)
return NULL;
down_read(&crypto_alg_sem);
list_for_each_entry(q, &crypto_alg_list, cra_list) {
if (!(strcmp(q->cra_name, name))) {
if (crypto_alg_get(q))
alg = q;
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 = 0;
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;
}
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 = kmalloc(tfm_size, GFP_KERNEL);
if (tfm == NULL)
goto out_put;
memset(tfm, 0, tfm_size);
tfm->__crt_alg = alg;
if (crypto_init_flags(tfm, flags))
goto out_free_tfm;
if (crypto_init_ops(tfm)) {
crypto_exit_ops(tfm);
goto out_free_tfm;
}
goto out;
out_free_tfm:
kfree(tfm);
tfm = NULL;
out_put:
crypto_alg_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;
crypto_exit_ops(tfm);
crypto_alg_put(alg);
memset(tfm, 0, size);
kfree(tfm);
}
int crypto_register_alg(struct crypto_alg *alg)
{
int ret = 0;
struct crypto_alg *q;
if (alg->cra_alignmask & (alg->cra_alignmask + 1))
return -EINVAL;
if (alg->cra_alignmask > PAGE_SIZE)
return -EINVAL;
down_write(&crypto_alg_sem);
list_for_each_entry(q, &crypto_alg_list, cra_list) {
if (!(strcmp(q->cra_name, alg->cra_name))) {
ret = -EEXIST;
goto out;
}
}
list_add_tail(&alg->cra_list, &crypto_alg_list);
out:
up_write(&crypto_alg_sem);
return ret;
}
int crypto_unregister_alg(struct crypto_alg *alg)
{
int ret = -ENOENT;
struct crypto_alg *q;
BUG_ON(!alg->cra_module);
down_write(&crypto_alg_sem);
list_for_each_entry(q, &crypto_alg_list, cra_list) {
if (alg == q) {
list_del(&alg->cra_list);
ret = 0;
goto out;
}
}
out:
up_write(&crypto_alg_sem);
return ret;
}
int crypto_alg_available(const char *name, u32 flags)
{
int ret = 0;
struct crypto_alg *alg = crypto_alg_mod_lookup(name);
if (alg) {
crypto_alg_put(alg);
ret = 1;
}
return ret;
}
static int __init init_crypto(void)
{
printk(KERN_INFO "Initializing Cryptographic API\n");
crypto_init_proc();
return 0;
}
__initcall(init_crypto);
EXPORT_SYMBOL_GPL(crypto_register_alg);
EXPORT_SYMBOL_GPL(crypto_unregister_alg);
EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
EXPORT_SYMBOL_GPL(crypto_free_tfm);
EXPORT_SYMBOL_GPL(crypto_alg_available);