[linux.git] / crypto / michael_mic.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Cryptographic API
 *
 * Michael MIC (IEEE 802.11i/TKIP) keyed digest
 *
 * Copyright (c) 2004 Jouni Malinen <[email protected]>
 */
#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)
		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_driver_name	=	"michael_mic-generic",
		.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);
}


subsys_initcall(michael_mic_init);
module_exit(michael_mic_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Michael MIC");
MODULE_AUTHOR("Jouni Malinen <[email protected]>");
MODULE_ALIAS_CRYPTO("michael_mic");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
1da177e4 LT	2	/*
	3	* Cryptographic API
	4	*
	5	* Michael MIC (IEEE 802.11i/TKIP) keyed digest
	6	*
85d32e7b	7	* Copyright (c) 2004 Jouni Malinen <[email protected]>
1da177e4	8	*/
19e2bf14	9	#include <crypto/internal/hash.h>
06ace7a9	10	#include <asm/byteorder.h>
1da177e4 LT	11	#include <linux/init.h>
	12	#include <linux/module.h>
	13	#include <linux/string.h>
06ace7a9	14	#include <linux/types.h>
1da177e4 LT	15
	16
	17	struct michael_mic_ctx {
19e2bf14 AKR	18	u32 l, r;
	19	};
	20
	21	struct michael_mic_desc_ctx {
1da177e4 LT	22	u8 pending[4];
	23	size_t pending_len;
	24
	25	u32 l, r;
	26	};
	27
1da177e4 LT	28	static inline u32 xswap(u32 val)
	29	{
	30	return ((val & 0x00ff00ff) << 8) \| ((val & 0xff00ff00) >> 8);
	31	}
	32
	33
	34	#define michael_block(l, r) \
	35	do { \
	36	r ^= rol32(l, 17); \
	37	l += r; \
	38	r ^= xswap(l); \
	39	l += r; \
	40	r ^= rol32(l, 3); \
	41	l += r; \
	42	r ^= ror32(l, 2); \
	43	l += r; \
	44	} while (0)
	45
	46
19e2bf14	47	static int michael_init(struct shash_desc *desc)
1da177e4	48	{
19e2bf14 AKR	49	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
19e2bf14 AKR	50	struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm);
1da177e4	51	mctx->pending_len = 0;
19e2bf14 AKR	52	mctx->l = ctx->l;
	53	mctx->r = ctx->r;
	54
	55	return 0;
1da177e4 LT	56	}
	57
	58
19e2bf14	59	static int michael_update(struct shash_desc desc, const u8 data,
6c2bb98b	60	unsigned int len)
1da177e4	61	{
19e2bf14	62	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
06ace7a9	63	const __le32 *src;
1da177e4 LT	64
	65	if (mctx->pending_len) {
	66	int flen = 4 - mctx->pending_len;
	67	if (flen > len)
	68	flen = len;
	69	memcpy(&mctx->pending[mctx->pending_len], data, flen);
	70	mctx->pending_len += flen;
	71	data += flen;
	72	len -= flen;
	73
	74	if (mctx->pending_len < 4)
19e2bf14	75	return 0;
1da177e4	76
06ace7a9 HX	77	src = (const __le32 *)mctx->pending;
06ace7a9 HX	78	mctx->l ^= le32_to_cpup(src);
1da177e4 LT	79	michael_block(mctx->l, mctx->r);
	80	mctx->pending_len = 0;
	81	}
	82
06ace7a9 HX	83	src = (const __le32 *)data;
06ace7a9 HX	84
1da177e4	85	while (len >= 4) {
06ace7a9	86	mctx->l ^= le32_to_cpup(src++);
1da177e4	87	michael_block(mctx->l, mctx->r);
1da177e4 LT	88	len -= 4;
	89	}
	90
	91	if (len > 0) {
	92	mctx->pending_len = len;
06ace7a9	93	memcpy(mctx->pending, src, len);
1da177e4	94	}
19e2bf14 AKR	95
19e2bf14 AKR	96	return 0;
1da177e4 LT	97	}
	98
	99
19e2bf14	100	static int michael_final(struct shash_desc desc, u8 out)
1da177e4	101	{
19e2bf14	102	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
1da177e4	103	u8 *data = mctx->pending;
06ace7a9	104	__le32 dst = (__le32 )out;
1da177e4 LT	105
	106	/* Last block and padding (0x5a, 4..7 x 0) */
	107	switch (mctx->pending_len) {
	108	case 0:
	109	mctx->l ^= 0x5a;
	110	break;
	111	case 1:
	112	mctx->l ^= data[0] \| 0x5a00;
	113	break;
	114	case 2:
	115	mctx->l ^= data[0] \| (data[1] << 8) \| 0x5a0000;
	116	break;
	117	case 3:
	118	mctx->l ^= data[0] \| (data[1] << 8) \| (data[2] << 16) \|
	119	0x5a000000;
	120	break;
	121	}
	122	michael_block(mctx->l, mctx->r);
	123	/* l ^= 0; */
	124	michael_block(mctx->l, mctx->r);
	125
06ace7a9 HX	126	dst[0] = cpu_to_le32(mctx->l);
06ace7a9 HX	127	dst[1] = cpu_to_le32(mctx->r);
19e2bf14 AKR	128
19e2bf14 AKR	129	return 0;
1da177e4 LT	130	}
	131
	132
19e2bf14	133	static int michael_setkey(struct crypto_shash tfm, const u8 key,
560c06ae	134	unsigned int keylen)
1da177e4	135	{
19e2bf14 AKR	136	struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm);
19e2bf14 AKR	137
06ace7a9 HX	138	const __le32 data = (const __le32 )key;
06ace7a9 HX	139
674f368a	140	if (keylen != 8)
1da177e4	141	return -EINVAL;
06ace7a9 HX	142
	143	mctx->l = le32_to_cpu(data[0]);
	144	mctx->r = le32_to_cpu(data[1]);
1da177e4 LT	145	return 0;
	146	}
	147
19e2bf14 AKR	148	static struct shash_alg alg = {
	149	.digestsize = 8,
	150	.setkey = michael_setkey,
	151	.init = michael_init,
	152	.update = michael_update,
	153	.final = michael_final,
	154	.descsize = sizeof(struct michael_mic_desc_ctx),
	155	.base = {
	156	.cra_name = "michael_mic",
d6ebf528	157	.cra_driver_name = "michael_mic-generic",
19e2bf14 AKR	158	.cra_blocksize = 8,
	159	.cra_alignmask = 3,
	160	.cra_ctxsize = sizeof(struct michael_mic_ctx),
	161	.cra_module = THIS_MODULE,
	162	}
1da177e4 LT	163	};
1da177e4 LT	164
1da177e4 LT	165	static int __init michael_mic_init(void)
1da177e4 LT	166	{
19e2bf14	167	return crypto_register_shash(&alg);
1da177e4 LT	168	}
	169
	170
	171	static void __exit michael_mic_exit(void)
	172	{
19e2bf14	173	crypto_unregister_shash(&alg);
1da177e4 LT	174	}
	175
	176
c4741b23	177	subsys_initcall(michael_mic_init);
1da177e4 LT	178	module_exit(michael_mic_exit);
	179
	180	MODULE_LICENSE("GPL v2");
	181	MODULE_DESCRIPTION("Michael MIC");
85d32e7b	182	MODULE_AUTHOR("Jouni Malinen <[email protected]>");
5d26a105	183	MODULE_ALIAS_CRYPTO("michael_mic");