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https://github.com/torvalds/linux
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25cdbcd9e5
The convention for setkey is that once it is set it should not change, in particular, init must not wipe out the key set by it. In fact, init should always be used after setkey before any digestion is performed. The only user of crc32c that sets the key is tcrypt. This patch adds the necessary init calls there. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
118 lines
2.6 KiB
C
118 lines
2.6 KiB
C
/*
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* Cryptographic API.
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*
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* CRC32C chksum
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*
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* This module file is a wrapper to invoke the lib/crc32c routines.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/crypto.h>
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#include <linux/crc32c.h>
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#include <linux/kernel.h>
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#define CHKSUM_BLOCK_SIZE 32
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#define CHKSUM_DIGEST_SIZE 4
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struct chksum_ctx {
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u32 crc;
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u32 key;
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};
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/*
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* Steps through buffer one byte at at time, calculates reflected
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* crc using table.
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*/
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static void chksum_init(struct crypto_tfm *tfm)
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{
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
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mctx->crc = mctx->key;
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}
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/*
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* Setting the seed allows arbitrary accumulators and flexible XOR policy
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* If your algorithm starts with ~0, then XOR with ~0 before you set
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* the seed.
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*/
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static int chksum_setkey(struct crypto_tfm *tfm, const u8 *key,
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unsigned int keylen, u32 *flags)
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{
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
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if (keylen != sizeof(mctx->crc)) {
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if (flags)
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*flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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}
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mctx->key = le32_to_cpu(*(__le32 *)key);
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return 0;
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}
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static void chksum_update(struct crypto_tfm *tfm, const u8 *data,
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unsigned int length)
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{
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
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mctx->crc = crc32c(mctx->crc, data, length);
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}
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static void chksum_final(struct crypto_tfm *tfm, u8 *out)
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{
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
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*(__le32 *)out = ~cpu_to_le32(mctx->crc);
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}
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static int crc32c_cra_init(struct crypto_tfm *tfm)
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{
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
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mctx->key = ~0;
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return 0;
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}
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static struct crypto_alg alg = {
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.cra_name = "crc32c",
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.cra_flags = CRYPTO_ALG_TYPE_DIGEST,
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.cra_blocksize = CHKSUM_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct chksum_ctx),
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.cra_module = THIS_MODULE,
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.cra_list = LIST_HEAD_INIT(alg.cra_list),
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.cra_init = crc32c_cra_init,
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.cra_u = {
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.digest = {
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.dia_digestsize= CHKSUM_DIGEST_SIZE,
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.dia_setkey = chksum_setkey,
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.dia_init = chksum_init,
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.dia_update = chksum_update,
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.dia_final = chksum_final
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}
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}
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};
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static int __init init(void)
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{
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return crypto_register_alg(&alg);
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}
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static void __exit fini(void)
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{
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crypto_unregister_alg(&alg);
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}
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module_init(init);
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module_exit(fini);
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MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
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MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
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MODULE_LICENSE("GPL");
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