linux-hardened/crypto/michael_mic.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

181 lines
3.4 KiB
C

/*
* Cryptographic API
*
* Michael MIC (IEEE 802.11i/TKIP) keyed digest
*
* Copyright (c) 2004 Jouni Malinen <jkmaline@cc.hut.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/crypto.h>
struct michael_mic_ctx {
u8 pending[4];
size_t pending_len;
u32 l, r;
};
static inline u32 xswap(u32 val)
{
return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
}
#define michael_block(l, r) \
do { \
r ^= rol32(l, 17); \
l += r; \
r ^= xswap(l); \
l += r; \
r ^= rol32(l, 3); \
l += r; \
r ^= ror32(l, 2); \
l += r; \
} while (0)
static inline u32 get_le32(const u8 *p)
{
return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
}
static inline void put_le32(u8 *p, u32 v)
{
p[0] = v;
p[1] = v >> 8;
p[2] = v >> 16;
p[3] = v >> 24;
}
static void michael_init(void *ctx)
{
struct michael_mic_ctx *mctx = ctx;
mctx->pending_len = 0;
}
static void michael_update(void *ctx, const u8 *data, unsigned int len)
{
struct michael_mic_ctx *mctx = ctx;
if (mctx->pending_len) {
int flen = 4 - mctx->pending_len;
if (flen > len)
flen = len;
memcpy(&mctx->pending[mctx->pending_len], data, flen);
mctx->pending_len += flen;
data += flen;
len -= flen;
if (mctx->pending_len < 4)
return;
mctx->l ^= get_le32(mctx->pending);
michael_block(mctx->l, mctx->r);
mctx->pending_len = 0;
}
while (len >= 4) {
mctx->l ^= get_le32(data);
michael_block(mctx->l, mctx->r);
data += 4;
len -= 4;
}
if (len > 0) {
mctx->pending_len = len;
memcpy(mctx->pending, data, len);
}
}
static void michael_final(void *ctx, u8 *out)
{
struct michael_mic_ctx *mctx = ctx;
u8 *data = mctx->pending;
/* Last block and padding (0x5a, 4..7 x 0) */
switch (mctx->pending_len) {
case 0:
mctx->l ^= 0x5a;
break;
case 1:
mctx->l ^= data[0] | 0x5a00;
break;
case 2:
mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000;
break;
case 3:
mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |
0x5a000000;
break;
}
michael_block(mctx->l, mctx->r);
/* l ^= 0; */
michael_block(mctx->l, mctx->r);
put_le32(out, mctx->l);
put_le32(out + 4, mctx->r);
}
static int michael_setkey(void *ctx, const u8 *key, unsigned int keylen,
u32 *flags)
{
struct michael_mic_ctx *mctx = ctx;
if (keylen != 8) {
if (flags)
*flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
mctx->l = get_le32(key);
mctx->r = get_le32(key + 4);
return 0;
}
static struct crypto_alg michael_mic_alg = {
.cra_name = "michael_mic",
.cra_flags = CRYPTO_ALG_TYPE_DIGEST,
.cra_blocksize = 8,
.cra_ctxsize = sizeof(struct michael_mic_ctx),
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(michael_mic_alg.cra_list),
.cra_u = { .digest = {
.dia_digestsize = 8,
.dia_init = michael_init,
.dia_update = michael_update,
.dia_final = michael_final,
.dia_setkey = michael_setkey } }
};
static int __init michael_mic_init(void)
{
return crypto_register_alg(&michael_mic_alg);
}
static void __exit michael_mic_exit(void)
{
crypto_unregister_alg(&michael_mic_alg);
}
module_init(michael_mic_init);
module_exit(michael_mic_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Michael MIC");
MODULE_AUTHOR("Jouni Malinen <jkmaline@cc.hut.fi>");