/* * Cryptographic API. * * CRC32C chksum * * This module file is a wrapper to invoke the lib/crc32c routines. * * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au> * * 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 <crypto/internal/hash.h> #include <linux/init.h> #include <linux/module.h> #include <linux/string.h> #include <linux/crc32c.h> #include <linux/kernel.h> #define CHKSUM_BLOCK_SIZE 1 #define CHKSUM_DIGEST_SIZE 4 struct chksum_ctx { u32 crc; u32 key; }; /* * Steps through buffer one byte at at time, calculates reflected * crc using table. */ static void chksum_init(struct crypto_tfm *tfm) { struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); mctx->crc = mctx->key; } /* * Setting the seed allows arbitrary accumulators and flexible XOR policy * If your algorithm starts with ~0, then XOR with ~0 before you set * the seed. */ static int chksum_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen) { struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); if (keylen != sizeof(mctx->crc)) { tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; return -EINVAL; } mctx->key = le32_to_cpu(*(__le32 *)key); return 0; } static void chksum_update(struct crypto_tfm *tfm, const u8 *data, unsigned int length) { struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); mctx->crc = crc32c(mctx->crc, data, length); } static void chksum_final(struct crypto_tfm *tfm, u8 *out) { struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); *(__le32 *)out = ~cpu_to_le32(mctx->crc); } static int crc32c_cra_init_old(struct crypto_tfm *tfm) { struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); mctx->key = ~0; return 0; } static struct crypto_alg old_alg = { .cra_name = "crc32c", .cra_flags = CRYPTO_ALG_TYPE_DIGEST, .cra_blocksize = CHKSUM_BLOCK_SIZE, .cra_ctxsize = sizeof(struct chksum_ctx), .cra_module = THIS_MODULE, .cra_list = LIST_HEAD_INIT(old_alg.cra_list), .cra_init = crc32c_cra_init_old, .cra_u = { .digest = { .dia_digestsize= CHKSUM_DIGEST_SIZE, .dia_setkey = chksum_setkey, .dia_init = chksum_init, .dia_update = chksum_update, .dia_final = chksum_final } } }; /* * Setting the seed allows arbitrary accumulators and flexible XOR policy * If your algorithm starts with ~0, then XOR with ~0 before you set * the seed. */ static int crc32c_setkey(struct crypto_ahash *hash, const u8 *key, unsigned int keylen) { u32 *mctx = crypto_ahash_ctx(hash); if (keylen != sizeof(u32)) { crypto_ahash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); return -EINVAL; } *mctx = le32_to_cpup((__le32 *)key); return 0; } static int crc32c_init(struct ahash_request *req) { u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); u32 *crcp = ahash_request_ctx(req); *crcp = *mctx; return 0; } static int crc32c_update(struct ahash_request *req) { struct crypto_hash_walk walk; u32 *crcp = ahash_request_ctx(req); u32 crc = *crcp; int nbytes; for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; nbytes = crypto_hash_walk_done(&walk, 0)) crc = crc32c(crc, walk.data, nbytes); *crcp = crc; return 0; } static int crc32c_final(struct ahash_request *req) { u32 *crcp = ahash_request_ctx(req); *(__le32 *)req->result = ~cpu_to_le32p(crcp); return 0; } static int crc32c_digest(struct ahash_request *req) { struct crypto_hash_walk walk; u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); u32 crc = *mctx; int nbytes; for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; nbytes = crypto_hash_walk_done(&walk, 0)) crc = crc32c(crc, walk.data, nbytes); *(__le32 *)req->result = ~cpu_to_le32(crc); return 0; } static int crc32c_cra_init(struct crypto_tfm *tfm) { u32 *key = crypto_tfm_ctx(tfm); *key = ~0; tfm->crt_ahash.reqsize = sizeof(u32); return 0; } static struct crypto_alg alg = { .cra_name = "crc32c", .cra_driver_name = "crc32c-generic", .cra_priority = 100, .cra_flags = CRYPTO_ALG_TYPE_AHASH, .cra_blocksize = CHKSUM_BLOCK_SIZE, .cra_alignmask = 3, .cra_ctxsize = sizeof(u32), .cra_module = THIS_MODULE, .cra_list = LIST_HEAD_INIT(alg.cra_list), .cra_init = crc32c_cra_init, .cra_type = &crypto_ahash_type, .cra_u = { .ahash = { .digestsize = CHKSUM_DIGEST_SIZE, .setkey = crc32c_setkey, .init = crc32c_init, .update = crc32c_update, .final = crc32c_final, .digest = crc32c_digest, } } }; static int __init crc32c_mod_init(void) { int err; err = crypto_register_alg(&old_alg); if (err) return err; err = crypto_register_alg(&alg); if (err) crypto_unregister_alg(&old_alg); return err; } static void __exit crc32c_mod_fini(void) { crypto_unregister_alg(&alg); crypto_unregister_alg(&old_alg); } module_init(crc32c_mod_init); module_exit(crc32c_mod_fini); MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c"); MODULE_LICENSE("GPL");