[deliverable/linux.git] / crypto / michael_mic.c

/*
 * Cryptographic API
 *
 * Michael MIC (IEEE 802.11i/TKIP) keyed digest
 *
 * Copyright (c) 2004 Jouni Malinen <j@w1.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 <crypto/internal/hash.h>
#include <asm/byteorder.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/types.h>


struct michael_mic_ctx {
	u32 l, r;
};

struct michael_mic_desc_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 int michael_init(struct shash_desc *desc)
{
	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
	struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm);
	mctx->pending_len = 0;
	mctx->l = ctx->l;
	mctx->r = ctx->r;

	return 0;
}


static int michael_update(struct shash_desc *desc, const u8 *data,
			   unsigned int len)
{
	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
	const __le32 *src;

	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 0;

		src = (const __le32 *)mctx->pending;
		mctx->l ^= le32_to_cpup(src);
		michael_block(mctx->l, mctx->r);
		mctx->pending_len = 0;
	}

	src = (const __le32 *)data;

	while (len >= 4) {
		mctx->l ^= le32_to_cpup(src++);
		michael_block(mctx->l, mctx->r);
		len -= 4;
	}

	if (len > 0) {
		mctx->pending_len = len;
		memcpy(mctx->pending, src, len);
	}

	return 0;
}


static int michael_final(struct shash_desc *desc, u8 *out)
{
	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
	u8 *data = mctx->pending;
	__le32 *dst = (__le32 *)out;

	/* 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);

	dst[0] = cpu_to_le32(mctx->l);
	dst[1] = cpu_to_le32(mctx->r);

	return 0;
}


static int michael_setkey(struct crypto_shash *tfm, const u8 *key,
			  unsigned int keylen)
{
	struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm);

	const __le32 *data = (const __le32 *)key;

	if (keylen != 8) {
		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
		return -EINVAL;
	}

	mctx->l = le32_to_cpu(data[0]);
	mctx->r = le32_to_cpu(data[1]);
	return 0;
}

static struct shash_alg alg = {
	.digestsize		=	8,
	.setkey			=	michael_setkey,
	.init			=	michael_init,
	.update			=	michael_update,
	.final			=	michael_final,
	.descsize		=	sizeof(struct michael_mic_desc_ctx),
	.base			=	{
		.cra_name		=	"michael_mic",
		.cra_blocksize		=	8,
		.cra_alignmask		=	3,
		.cra_ctxsize		=	sizeof(struct michael_mic_ctx),
		.cra_module		=	THIS_MODULE,
	}
};

static int __init michael_mic_init(void)
{
	return crypto_register_shash(&alg);
}


static void __exit michael_mic_exit(void)
{
	crypto_unregister_shash(&alg);
}


module_init(michael_mic_init);
module_exit(michael_mic_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Michael MIC");
MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Cryptographic API
	3	*
	4	* Michael MIC (IEEE 802.11i/TKIP) keyed digest
	5	*
85d32e7b	6	* Copyright (c) 2004 Jouni Malinen <j@w1.fi>
1da177e4 LT	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
19e2bf14	12	#include <crypto/internal/hash.h>
06ace7a9	13	#include <asm/byteorder.h>
1da177e4 LT	14	#include <linux/init.h>
	15	#include <linux/module.h>
	16	#include <linux/string.h>
06ace7a9	17	#include <linux/types.h>
1da177e4 LT	18
	19
	20	struct michael_mic_ctx {
19e2bf14 AKR	21	u32 l, r;
	22	};
	23
	24	struct michael_mic_desc_ctx {
1da177e4 LT	25	u8 pending[4];
	26	size_t pending_len;
	27
	28	u32 l, r;
	29	};
	30
1da177e4 LT	31	static inline u32 xswap(u32 val)
	32	{
	33	return ((val & 0x00ff00ff) << 8) \| ((val & 0xff00ff00) >> 8);
	34	}
	35
	36
	37	#define michael_block(l, r) \
	38	do { \
	39	r ^= rol32(l, 17); \
	40	l += r; \
	41	r ^= xswap(l); \
	42	l += r; \
	43	r ^= rol32(l, 3); \
	44	l += r; \
	45	r ^= ror32(l, 2); \
	46	l += r; \
	47	} while (0)
	48
	49
19e2bf14	50	static int michael_init(struct shash_desc *desc)
1da177e4	51	{
19e2bf14 AKR	52	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
19e2bf14 AKR	53	struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm);
1da177e4	54	mctx->pending_len = 0;
19e2bf14 AKR	55	mctx->l = ctx->l;
	56	mctx->r = ctx->r;
	57
	58	return 0;
1da177e4 LT	59	}
	60
	61
19e2bf14	62	static int michael_update(struct shash_desc desc, const u8 data,
6c2bb98b	63	unsigned int len)
1da177e4	64	{
19e2bf14	65	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
06ace7a9	66	const __le32 *src;
1da177e4 LT	67
	68	if (mctx->pending_len) {
	69	int flen = 4 - mctx->pending_len;
	70	if (flen > len)
	71	flen = len;
	72	memcpy(&mctx->pending[mctx->pending_len], data, flen);
	73	mctx->pending_len += flen;
	74	data += flen;
	75	len -= flen;
	76
	77	if (mctx->pending_len < 4)
19e2bf14	78	return 0;
1da177e4	79
06ace7a9 HX	80	src = (const __le32 *)mctx->pending;
06ace7a9 HX	81	mctx->l ^= le32_to_cpup(src);
1da177e4 LT	82	michael_block(mctx->l, mctx->r);
	83	mctx->pending_len = 0;
	84	}
	85
06ace7a9 HX	86	src = (const __le32 *)data;
06ace7a9 HX	87
1da177e4	88	while (len >= 4) {
06ace7a9	89	mctx->l ^= le32_to_cpup(src++);
1da177e4	90	michael_block(mctx->l, mctx->r);
1da177e4 LT	91	len -= 4;
	92	}
	93
	94	if (len > 0) {
	95	mctx->pending_len = len;
06ace7a9	96	memcpy(mctx->pending, src, len);
1da177e4	97	}
19e2bf14 AKR	98
19e2bf14 AKR	99	return 0;
1da177e4 LT	100	}
	101
	102
19e2bf14	103	static int michael_final(struct shash_desc desc, u8 out)
1da177e4	104	{
19e2bf14	105	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
1da177e4	106	u8 *data = mctx->pending;
06ace7a9	107	__le32 dst = (__le32 )out;
1da177e4 LT	108
	109	/* Last block and padding (0x5a, 4..7 x 0) */
	110	switch (mctx->pending_len) {
	111	case 0:
	112	mctx->l ^= 0x5a;
	113	break;
	114	case 1:
	115	mctx->l ^= data[0] \| 0x5a00;
	116	break;
	117	case 2:
	118	mctx->l ^= data[0] \| (data[1] << 8) \| 0x5a0000;
	119	break;
	120	case 3:
	121	mctx->l ^= data[0] \| (data[1] << 8) \| (data[2] << 16) \|
	122	0x5a000000;
	123	break;
	124	}
	125	michael_block(mctx->l, mctx->r);
	126	/* l ^= 0; */
	127	michael_block(mctx->l, mctx->r);
	128
06ace7a9 HX	129	dst[0] = cpu_to_le32(mctx->l);
06ace7a9 HX	130	dst[1] = cpu_to_le32(mctx->r);
19e2bf14 AKR	131
19e2bf14 AKR	132	return 0;
1da177e4 LT	133	}
	134
	135
19e2bf14	136	static int michael_setkey(struct crypto_shash tfm, const u8 key,
560c06ae	137	unsigned int keylen)
1da177e4	138	{
19e2bf14 AKR	139	struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm);
19e2bf14 AKR	140
06ace7a9 HX	141	const __le32 data = (const __le32 )key;
06ace7a9 HX	142
1da177e4	143	if (keylen != 8) {
19e2bf14	144	crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
1da177e4 LT	145	return -EINVAL;
1da177e4 LT	146	}
06ace7a9 HX	147
	148	mctx->l = le32_to_cpu(data[0]);
	149	mctx->r = le32_to_cpu(data[1]);
1da177e4 LT	150	return 0;
	151	}
	152
19e2bf14 AKR	153	static struct shash_alg alg = {
	154	.digestsize = 8,
	155	.setkey = michael_setkey,
	156	.init = michael_init,
	157	.update = michael_update,
	158	.final = michael_final,
	159	.descsize = sizeof(struct michael_mic_desc_ctx),
	160	.base = {
	161	.cra_name = "michael_mic",
	162	.cra_blocksize = 8,
	163	.cra_alignmask = 3,
	164	.cra_ctxsize = sizeof(struct michael_mic_ctx),
	165	.cra_module = THIS_MODULE,
	166	}
1da177e4 LT	167	};
1da177e4 LT	168
1da177e4 LT	169	static int __init michael_mic_init(void)
1da177e4 LT	170	{
19e2bf14	171	return crypto_register_shash(&alg);
1da177e4 LT	172	}
	173
	174
	175	static void __exit michael_mic_exit(void)
	176	{
19e2bf14	177	crypto_unregister_shash(&alg);
1da177e4 LT	178	}
	179
	180
	181	module_init(michael_mic_init);
	182	module_exit(michael_mic_exit);
	183
	184	MODULE_LICENSE("GPL v2");
	185	MODULE_DESCRIPTION("Michael MIC");
85d32e7b	186	MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");