// 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");