135 lines
3.4 KiB
C
135 lines
3.4 KiB
C
/*
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* Cryptographic API.
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*
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* HMAC: Keyed-Hashing for Message Authentication (RFC2104).
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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*
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* The HMAC implementation is derived from USAGI.
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* Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
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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/crypto.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <asm/scatterlist.h>
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#include "internal.h"
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static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen)
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{
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struct scatterlist tmp;
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tmp.page = virt_to_page(key);
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tmp.offset = offset_in_page(key);
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tmp.length = keylen;
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crypto_digest_digest(tfm, &tmp, 1, key);
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}
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int crypto_alloc_hmac_block(struct crypto_tfm *tfm)
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{
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int ret = 0;
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BUG_ON(!crypto_tfm_alg_blocksize(tfm));
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tfm->crt_digest.dit_hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm),
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GFP_KERNEL);
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if (tfm->crt_digest.dit_hmac_block == NULL)
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ret = -ENOMEM;
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return ret;
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}
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void crypto_free_hmac_block(struct crypto_tfm *tfm)
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{
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if (tfm->crt_digest.dit_hmac_block)
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kfree(tfm->crt_digest.dit_hmac_block);
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}
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void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen)
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{
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unsigned int i;
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struct scatterlist tmp;
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char *ipad = tfm->crt_digest.dit_hmac_block;
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if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
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hash_key(tfm, key, *keylen);
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*keylen = crypto_tfm_alg_digestsize(tfm);
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}
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memset(ipad, 0, crypto_tfm_alg_blocksize(tfm));
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memcpy(ipad, key, *keylen);
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for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
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ipad[i] ^= 0x36;
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tmp.page = virt_to_page(ipad);
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tmp.offset = offset_in_page(ipad);
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tmp.length = crypto_tfm_alg_blocksize(tfm);
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crypto_digest_init(tfm);
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crypto_digest_update(tfm, &tmp, 1);
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}
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void crypto_hmac_update(struct crypto_tfm *tfm,
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struct scatterlist *sg, unsigned int nsg)
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{
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crypto_digest_update(tfm, sg, nsg);
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}
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void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key,
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unsigned int *keylen, u8 *out)
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{
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unsigned int i;
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struct scatterlist tmp;
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char *opad = tfm->crt_digest.dit_hmac_block;
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if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
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hash_key(tfm, key, *keylen);
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*keylen = crypto_tfm_alg_digestsize(tfm);
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}
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crypto_digest_final(tfm, out);
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memset(opad, 0, crypto_tfm_alg_blocksize(tfm));
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memcpy(opad, key, *keylen);
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for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
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opad[i] ^= 0x5c;
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tmp.page = virt_to_page(opad);
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tmp.offset = offset_in_page(opad);
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tmp.length = crypto_tfm_alg_blocksize(tfm);
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crypto_digest_init(tfm);
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crypto_digest_update(tfm, &tmp, 1);
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tmp.page = virt_to_page(out);
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tmp.offset = offset_in_page(out);
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tmp.length = crypto_tfm_alg_digestsize(tfm);
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crypto_digest_update(tfm, &tmp, 1);
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crypto_digest_final(tfm, out);
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}
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void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen,
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struct scatterlist *sg, unsigned int nsg, u8 *out)
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{
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crypto_hmac_init(tfm, key, keylen);
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crypto_hmac_update(tfm, sg, nsg);
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crypto_hmac_final(tfm, key, keylen, out);
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}
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EXPORT_SYMBOL_GPL(crypto_hmac_init);
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EXPORT_SYMBOL_GPL(crypto_hmac_update);
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EXPORT_SYMBOL_GPL(crypto_hmac_final);
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EXPORT_SYMBOL_GPL(crypto_hmac);
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