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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Cryptographic API.
*
* Null algorithms, aka Much Ado About Nothing.
*
* These are needed for IPsec, and may be useful in general for
* testing & debugging.
*
* The null cipher is compliant with RFC2410.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
*/
#include <crypto/null.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/string.h>
static DEFINE_MUTEX(crypto_default_null_skcipher_lock);
static struct crypto_sync_skcipher *crypto_default_null_skcipher;
static int crypto_default_null_skcipher_refcnt;
static int null_compress(struct crypto_tfm *tfm, const u8 *src,
unsigned int slen, u8 *dst, unsigned int *dlen)
{
if (slen > *dlen)
return -EINVAL;
memcpy(dst, src, slen);
*dlen = slen;
return 0;
}
static int null_init(struct shash_desc *desc)
{
return 0;
}
static int null_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
return 0;
}
static int null_final(struct shash_desc *desc, u8 *out)
{
return 0;
}
static int null_digest(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return 0;
}
static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{ return 0; }
static int null_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keylen)
{ return 0; }
static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{ return 0; }
static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
memcpy(dst, src, NULL_BLOCK_SIZE);
}
static int null_skcipher_crypt(struct skcipher_request *req)
{
struct skcipher_walk walk;
int err;
err = skcipher_walk_virt(&walk, req, false);
while (walk.nbytes) {
if (walk.src.virt.addr != walk.dst.virt.addr)
memcpy(walk.dst.virt.addr, walk.src.virt.addr,
walk.nbytes);
err = skcipher_walk_done(&walk, 0);
}
return err;
}
static struct shash_alg digest_null = {
.digestsize = NULL_DIGEST_SIZE,
.setkey = null_hash_setkey,
.init = null_init,
.update = null_update,
.finup = null_digest,
.digest = null_digest,
.final = null_final,
.base = {
.cra_name = "digest_null",
.cra_blocksize = NULL_BLOCK_SIZE,
.cra_module = THIS_MODULE,
}
};
static struct skcipher_alg skcipher_null = {
.base.cra_name = "ecb(cipher_null)",
.base.cra_driver_name = "ecb-cipher_null",
.base.cra_priority = 100,
.base.cra_blocksize = NULL_BLOCK_SIZE,
.base.cra_ctxsize = 0,
.base.cra_module = THIS_MODULE,
.min_keysize = NULL_KEY_SIZE,
.max_keysize = NULL_KEY_SIZE,
.ivsize = NULL_IV_SIZE,
.setkey = null_skcipher_setkey,
.encrypt = null_skcipher_crypt,
.decrypt = null_skcipher_crypt,
};
static struct crypto_alg null_algs[] = { {
.cra_name = "cipher_null",
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = NULL_BLOCK_SIZE,
.cra_ctxsize = 0,
.cra_module = THIS_MODULE,
.cra_u = { .cipher = {
.cia_min_keysize = NULL_KEY_SIZE,
.cia_max_keysize = NULL_KEY_SIZE,
.cia_setkey = null_setkey,
.cia_encrypt = null_crypt,
.cia_decrypt = null_crypt } }
}, {
.cra_name = "compress_null",
.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
.cra_blocksize = NULL_BLOCK_SIZE,
.cra_ctxsize = 0,
.cra_module = THIS_MODULE,
.cra_u = { .compress = {
.coa_compress = null_compress,
.coa_decompress = null_compress } }
} };
MODULE_ALIAS_CRYPTO("compress_null");
MODULE_ALIAS_CRYPTO("digest_null");
MODULE_ALIAS_CRYPTO("cipher_null");
struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void)
{
struct crypto_sync_skcipher *tfm;
mutex_lock(&crypto_default_null_skcipher_lock);
tfm = crypto_default_null_skcipher;
if (!tfm) {
tfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0);
if (IS_ERR(tfm))
goto unlock;
crypto_default_null_skcipher = tfm;
}
crypto_default_null_skcipher_refcnt++;
unlock:
mutex_unlock(&crypto_default_null_skcipher_lock);
return tfm;
}
EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher);
void crypto_put_default_null_skcipher(void)
{
mutex_lock(&crypto_default_null_skcipher_lock);
if (!--crypto_default_null_skcipher_refcnt) {
crypto_free_sync_skcipher(crypto_default_null_skcipher);
crypto_default_null_skcipher = NULL;
}
mutex_unlock(&crypto_default_null_skcipher_lock);
}
EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher);
static int __init crypto_null_mod_init(void)
{
int ret = 0;
ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs));
if (ret < 0)
goto out;
ret = crypto_register_shash(&digest_null);
if (ret < 0)
goto out_unregister_algs;
ret = crypto_register_skcipher(&skcipher_null);
if (ret < 0)
goto out_unregister_shash;
return 0;
out_unregister_shash:
crypto_unregister_shash(&digest_null);
out_unregister_algs:
crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
out:
return ret;
}
static void __exit crypto_null_mod_fini(void)
{
crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
crypto_unregister_shash(&digest_null);
crypto_unregister_skcipher(&skcipher_null);
}
subsys_initcall(crypto_null_mod_init);
module_exit(crypto_null_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Null Cryptographic Algorithms");
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