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crypto/hmac.c
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1da177e4c
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/* * Cryptographic API. * * HMAC: Keyed-Hashing for Message Authentication (RFC2104). * * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> * * The HMAC implementation is derived from USAGI. * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI * * 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 <linux/crypto.h> #include <linux/mm.h> #include <linux/highmem.h> #include <linux/slab.h> #include <asm/scatterlist.h> #include "internal.h" static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen) { struct scatterlist tmp; tmp.page = virt_to_page(key); tmp.offset = offset_in_page(key); tmp.length = keylen; crypto_digest_digest(tfm, &tmp, 1, key); } int crypto_alloc_hmac_block(struct crypto_tfm *tfm) { int ret = 0; BUG_ON(!crypto_tfm_alg_blocksize(tfm)); tfm->crt_digest.dit_hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm), GFP_KERNEL); if (tfm->crt_digest.dit_hmac_block == NULL) ret = -ENOMEM; return ret; } void crypto_free_hmac_block(struct crypto_tfm *tfm) { if (tfm->crt_digest.dit_hmac_block) kfree(tfm->crt_digest.dit_hmac_block); } void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen) { unsigned int i; struct scatterlist tmp; char *ipad = tfm->crt_digest.dit_hmac_block; if (*keylen > crypto_tfm_alg_blocksize(tfm)) { hash_key(tfm, key, *keylen); *keylen = crypto_tfm_alg_digestsize(tfm); } memset(ipad, 0, crypto_tfm_alg_blocksize(tfm)); memcpy(ipad, key, *keylen); for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++) ipad[i] ^= 0x36; tmp.page = virt_to_page(ipad); tmp.offset = offset_in_page(ipad); tmp.length = crypto_tfm_alg_blocksize(tfm); crypto_digest_init(tfm); crypto_digest_update(tfm, &tmp, 1); } void crypto_hmac_update(struct crypto_tfm *tfm, struct scatterlist *sg, unsigned int nsg) { crypto_digest_update(tfm, sg, nsg); } void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen, u8 *out) { unsigned int i; struct scatterlist tmp; char *opad = tfm->crt_digest.dit_hmac_block; if (*keylen > crypto_tfm_alg_blocksize(tfm)) { hash_key(tfm, key, *keylen); *keylen = crypto_tfm_alg_digestsize(tfm); } crypto_digest_final(tfm, out); memset(opad, 0, crypto_tfm_alg_blocksize(tfm)); memcpy(opad, key, *keylen); for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++) opad[i] ^= 0x5c; tmp.page = virt_to_page(opad); tmp.offset = offset_in_page(opad); tmp.length = crypto_tfm_alg_blocksize(tfm); crypto_digest_init(tfm); crypto_digest_update(tfm, &tmp, 1); tmp.page = virt_to_page(out); tmp.offset = offset_in_page(out); tmp.length = crypto_tfm_alg_digestsize(tfm); crypto_digest_update(tfm, &tmp, 1); crypto_digest_final(tfm, out); } void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen, struct scatterlist *sg, unsigned int nsg, u8 *out) { crypto_hmac_init(tfm, key, keylen); crypto_hmac_update(tfm, sg, nsg); crypto_hmac_final(tfm, key, keylen, out); } EXPORT_SYMBOL_GPL(crypto_hmac_init); EXPORT_SYMBOL_GPL(crypto_hmac_update); EXPORT_SYMBOL_GPL(crypto_hmac_final); EXPORT_SYMBOL_GPL(crypto_hmac); |