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/crypto/hmac.c

https://bitbucket.org/evzijst/gittest
C | 134 lines | 90 code | 28 blank | 16 comment | 7 complexity | 8ccf294cccce496f94216c913bb3d790 MD5 | raw file
  1/*
  2 * Cryptographic API.
  3 *
  4 * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
  5 *
  6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  7 *
  8 * The HMAC implementation is derived from USAGI.
  9 * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
 10 *
 11 * This program is free software; you can redistribute it and/or modify it
 12 * under the terms of the GNU General Public License as published by the Free
 13 * Software Foundation; either version 2 of the License, or (at your option) 
 14 * any later version.
 15 *
 16 */
 17#include <linux/crypto.h>
 18#include <linux/mm.h>
 19#include <linux/highmem.h>
 20#include <linux/slab.h>
 21#include <asm/scatterlist.h>
 22#include "internal.h"
 23
 24static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen)
 25{
 26	struct scatterlist tmp;
 27	
 28	tmp.page = virt_to_page(key);
 29	tmp.offset = offset_in_page(key);
 30	tmp.length = keylen;
 31	crypto_digest_digest(tfm, &tmp, 1, key);
 32		
 33}
 34
 35int crypto_alloc_hmac_block(struct crypto_tfm *tfm)
 36{
 37	int ret = 0;
 38
 39	BUG_ON(!crypto_tfm_alg_blocksize(tfm));
 40	
 41	tfm->crt_digest.dit_hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm),
 42	                                         GFP_KERNEL);
 43	if (tfm->crt_digest.dit_hmac_block == NULL)
 44		ret = -ENOMEM;
 45
 46	return ret;
 47		
 48}
 49
 50void crypto_free_hmac_block(struct crypto_tfm *tfm)
 51{
 52	if (tfm->crt_digest.dit_hmac_block)
 53		kfree(tfm->crt_digest.dit_hmac_block);
 54}
 55
 56void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen)
 57{
 58	unsigned int i;
 59	struct scatterlist tmp;
 60	char *ipad = tfm->crt_digest.dit_hmac_block;
 61	
 62	if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
 63		hash_key(tfm, key, *keylen);
 64		*keylen = crypto_tfm_alg_digestsize(tfm);
 65	}
 66
 67	memset(ipad, 0, crypto_tfm_alg_blocksize(tfm));
 68	memcpy(ipad, key, *keylen);
 69
 70	for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
 71		ipad[i] ^= 0x36;
 72
 73	tmp.page = virt_to_page(ipad);
 74	tmp.offset = offset_in_page(ipad);
 75	tmp.length = crypto_tfm_alg_blocksize(tfm);
 76	
 77	crypto_digest_init(tfm);
 78	crypto_digest_update(tfm, &tmp, 1);
 79}
 80
 81void crypto_hmac_update(struct crypto_tfm *tfm,
 82                        struct scatterlist *sg, unsigned int nsg)
 83{
 84	crypto_digest_update(tfm, sg, nsg);
 85}
 86
 87void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key,
 88                       unsigned int *keylen, u8 *out)
 89{
 90	unsigned int i;
 91	struct scatterlist tmp;
 92	char *opad = tfm->crt_digest.dit_hmac_block;
 93	
 94	if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
 95		hash_key(tfm, key, *keylen);
 96		*keylen = crypto_tfm_alg_digestsize(tfm);
 97	}
 98
 99	crypto_digest_final(tfm, out);
100
101	memset(opad, 0, crypto_tfm_alg_blocksize(tfm));
102	memcpy(opad, key, *keylen);
103		
104	for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
105		opad[i] ^= 0x5c;
106
107	tmp.page = virt_to_page(opad);
108	tmp.offset = offset_in_page(opad);
109	tmp.length = crypto_tfm_alg_blocksize(tfm);
110
111	crypto_digest_init(tfm);
112	crypto_digest_update(tfm, &tmp, 1);
113	
114	tmp.page = virt_to_page(out);
115	tmp.offset = offset_in_page(out);
116	tmp.length = crypto_tfm_alg_digestsize(tfm);
117	
118	crypto_digest_update(tfm, &tmp, 1);
119	crypto_digest_final(tfm, out);
120}
121
122void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen,
123                 struct scatterlist *sg, unsigned int nsg, u8 *out)
124{
125	crypto_hmac_init(tfm, key, keylen);
126	crypto_hmac_update(tfm, sg, nsg);
127	crypto_hmac_final(tfm, key, keylen, out);
128}
129
130EXPORT_SYMBOL_GPL(crypto_hmac_init);
131EXPORT_SYMBOL_GPL(crypto_hmac_update);
132EXPORT_SYMBOL_GPL(crypto_hmac_final);
133EXPORT_SYMBOL_GPL(crypto_hmac);
134