[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/unaligned.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 {
	__le32 pending;
	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);

	if (mctx->pending_len) {
		int flen = 4 - mctx->pending_len;
		if (flen > len)
			flen = len;
		memcpy((u8 *)&mctx->pending + mctx->pending_len, data, flen);
		mctx->pending_len += flen;
		data += flen;
		len -= flen;

		if (mctx->pending_len < 4)
			return 0;

		mctx->l ^= le32_to_cpu(mctx->pending);
		michael_block(mctx->l, mctx->r);
		mctx->pending_len = 0;
	}

	while (len >= 4) {
		mctx->l ^= get_unaligned_le32(data);
		michael_block(mctx->l, mctx->r);
		data += 4;
		len -= 4;
	}

	if (len > 0) {
		mctx->pending_len = len;
		memcpy(&mctx->pending, data, 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 = (u8 *)&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_unaligned_le32(mctx->l, out);
	put_unaligned_le32(mctx->r, out + 4);

	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);

	if (keylen != 8)
		return -EINVAL;

	mctx->l = get_unaligned_le32(key);
	mctx->r = get_unaligned_le32(key + 4);
	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_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>
e1b2d980	10	#include <asm/unaligned.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 {
e1b2d980	22	__le32 pending;
1da177e4 LT	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);
1da177e4 LT	63
	64	if (mctx->pending_len) {
	65	int flen = 4 - mctx->pending_len;
	66	if (flen > len)
	67	flen = len;
e1b2d980	68	memcpy((u8 *)&mctx->pending + mctx->pending_len, data, flen);
1da177e4 LT	69	mctx->pending_len += flen;
	70	data += flen;
	71	len -= flen;
	72
	73	if (mctx->pending_len < 4)
19e2bf14	74	return 0;
1da177e4	75
e1b2d980	76	mctx->l ^= le32_to_cpu(mctx->pending);
1da177e4 LT	77	michael_block(mctx->l, mctx->r);
	78	mctx->pending_len = 0;
	79	}
	80
	81	while (len >= 4) {
e1b2d980	82	mctx->l ^= get_unaligned_le32(data);
1da177e4	83	michael_block(mctx->l, mctx->r);
e1b2d980	84	data += 4;
1da177e4 LT	85	len -= 4;
	86	}
	87
	88	if (len > 0) {
	89	mctx->pending_len = len;
e1b2d980	90	memcpy(&mctx->pending, data, len);
1da177e4	91	}
19e2bf14 AKR	92
19e2bf14 AKR	93	return 0;
1da177e4 LT	94	}
	95
	96
19e2bf14	97	static int michael_final(struct shash_desc desc, u8 out)
1da177e4	98	{
19e2bf14	99	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
e1b2d980	100	u8 data = (u8 )&mctx->pending;
1da177e4 LT	101
	102	/* Last block and padding (0x5a, 4..7 x 0) */
	103	switch (mctx->pending_len) {
	104	case 0:
	105	mctx->l ^= 0x5a;
	106	break;
	107	case 1:
	108	mctx->l ^= data[0] \| 0x5a00;
	109	break;
	110	case 2:
	111	mctx->l ^= data[0] \| (data[1] << 8) \| 0x5a0000;
	112	break;
	113	case 3:
	114	mctx->l ^= data[0] \| (data[1] << 8) \| (data[2] << 16) \|
	115	0x5a000000;
	116	break;
	117	}
	118	michael_block(mctx->l, mctx->r);
	119	/* l ^= 0; */
	120	michael_block(mctx->l, mctx->r);
	121
e1b2d980 AB	122	put_unaligned_le32(mctx->l, out);
e1b2d980 AB	123	put_unaligned_le32(mctx->r, out + 4);
19e2bf14 AKR	124
19e2bf14 AKR	125	return 0;
1da177e4 LT	126	}
	127
	128
19e2bf14	129	static int michael_setkey(struct crypto_shash tfm, const u8 key,
560c06ae	130	unsigned int keylen)
1da177e4	131	{
19e2bf14 AKR	132	struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm);
19e2bf14 AKR	133
674f368a	134	if (keylen != 8)
1da177e4	135	return -EINVAL;
06ace7a9	136
e1b2d980 AB	137	mctx->l = get_unaligned_le32(key);
e1b2d980 AB	138	mctx->r = get_unaligned_le32(key + 4);
1da177e4 LT	139	return 0;
	140	}
	141
19e2bf14 AKR	142	static struct shash_alg alg = {
	143	.digestsize = 8,
	144	.setkey = michael_setkey,
	145	.init = michael_init,
	146	.update = michael_update,
	147	.final = michael_final,
	148	.descsize = sizeof(struct michael_mic_desc_ctx),
	149	.base = {
	150	.cra_name = "michael_mic",
d6ebf528	151	.cra_driver_name = "michael_mic-generic",
19e2bf14	152	.cra_blocksize = 8,
19e2bf14 AKR	153	.cra_ctxsize = sizeof(struct michael_mic_ctx),
	154	.cra_module = THIS_MODULE,
	155	}
1da177e4 LT	156	};
1da177e4 LT	157
1da177e4 LT	158	static int __init michael_mic_init(void)
1da177e4 LT	159	{
19e2bf14	160	return crypto_register_shash(&alg);
1da177e4 LT	161	}
	162
	163
	164	static void __exit michael_mic_exit(void)
	165	{
19e2bf14	166	crypto_unregister_shash(&alg);
1da177e4 LT	167	}
	168
	169
c4741b23	170	subsys_initcall(michael_mic_init);
1da177e4 LT	171	module_exit(michael_mic_exit);
	172
	173	MODULE_LICENSE("GPL v2");
	174	MODULE_DESCRIPTION("Michael MIC");
85d32e7b	175	MODULE_AUTHOR("Jouni Malinen <[email protected]>");
5d26a105	176	MODULE_ALIAS_CRYPTO("michael_mic");