diff options
Diffstat (limited to 'crypto/crypto_null.c')
| -rw-r--r-- | crypto/crypto_null.c | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/crypto/crypto_null.c b/crypto/crypto_null.c new file mode 100644 index 0000000000..5b84b0f7cc --- /dev/null +++ b/crypto/crypto_null.c @@ -0,0 +1,225 @@ +// 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_driver_name = "digest_null-generic", + .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_driver_name = "cipher_null-generic", + .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_driver_name = "compress_null-generic", + .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"); |