[deliverable/linux.git] / drivers / staging / rtl8187se / ieee80211 / ieee80211_crypt_wep.c

/*
 * Host AP crypt: host-based WEP encryption implementation for Host AP driver
 *
 * Copyright (c) 2002-2004, 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. See README and COPYING for
 * more details.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

//#include <linux/config.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/skbuff.h>
#include <linux/string.h>

#include "ieee80211.h"

#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <linux/crc32.h>

MODULE_AUTHOR("Jouni Malinen");
MODULE_DESCRIPTION("Host AP crypt: WEP");
MODULE_LICENSE("GPL");


struct prism2_wep_data {
	u32 iv;
#define WEP_KEY_LEN 13
	u8 key[WEP_KEY_LEN + 1];
	u8 key_len;
	u8 key_idx;
	struct crypto_blkcipher *tx_tfm;
	struct crypto_blkcipher *rx_tfm;
};


static void *prism2_wep_init(int keyidx)
{
	struct prism2_wep_data *priv;

	priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
	if (priv == NULL)
		goto fail;
	priv->key_idx = keyidx;
	priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(priv->tx_tfm)) {
		pr_debug("could not allocate crypto API arc4\n");
		priv->tx_tfm = NULL;
		goto fail;
	}
	priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(priv->rx_tfm)) {
		pr_debug("could not allocate crypto API arc4\n");
		priv->rx_tfm = NULL;
		goto fail;
	}

	/* start WEP IV from a random value */
	get_random_bytes(&priv->iv, 4);

	return priv;

fail:
	if (priv) {
		if (priv->tx_tfm)
			crypto_free_blkcipher(priv->tx_tfm);
		if (priv->rx_tfm)
			crypto_free_blkcipher(priv->rx_tfm);
		kfree(priv);
	}

	return NULL;
}


static void prism2_wep_deinit(void *priv)
{
	struct prism2_wep_data *_priv = priv;

	if (_priv) {
		if (_priv->tx_tfm)
			crypto_free_blkcipher(_priv->tx_tfm);
		if (_priv->rx_tfm)
			crypto_free_blkcipher(_priv->rx_tfm);
	}

	kfree(priv);
}


/* Perform WEP encryption on given skb that has at least 4 bytes of headroom
 * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
 * so the payload length increases with 8 bytes.
 *
 * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
 */
static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
{
	struct prism2_wep_data *wep = priv;
	struct blkcipher_desc desc = { .tfm = wep->tx_tfm };
	u32 klen, len;
	u8 key[WEP_KEY_LEN + 3];
	u8 *pos;
	u32 crc;
	u8 *icv;
	struct scatterlist sg;

	if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
	    skb->len < hdr_len)
		return -1;

	len = skb->len - hdr_len;
	pos = skb_push(skb, 4);
	memmove(pos, pos + 4, hdr_len);
	pos += hdr_len;

	klen = 3 + wep->key_len;

	wep->iv++;

	/* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
	 * scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
	 * can be used to speedup attacks, so avoid using them. */
	if ((wep->iv & 0xff00) == 0xff00) {
		u8 B = (wep->iv >> 16) & 0xff;
		if (B >= 3 && B < klen)
			wep->iv += 0x0100;
	}

	/* Prepend 24-bit IV to RC4 key and TX frame */
	*pos++ = key[0] = (wep->iv >> 16) & 0xff;
	*pos++ = key[1] = (wep->iv >> 8) & 0xff;
	*pos++ = key[2] = wep->iv & 0xff;
	*pos++ = wep->key_idx << 6;

	/* Copy rest of the WEP key (the secret part) */
	memcpy(key + 3, wep->key, wep->key_len);

	/* Append little-endian CRC32 and encrypt it to produce ICV */
	crc = ~crc32_le(~0, pos, len);
	icv = skb_put(skb, 4);
	icv[0] = crc;
	icv[1] = crc >> 8;
	icv[2] = crc >> 16;
	icv[3] = crc >> 24;

	crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
	sg_init_one(&sg, pos, len + 4);

	return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
}


/* Perform WEP decryption on given buffer. Buffer includes whole WEP part of
 * the frame: IV (4 bytes), encrypted payload (including SNAP header),
 * ICV (4 bytes). len includes both IV and ICV.
 *
 * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
 * failure. If frame is OK, IV and ICV will be removed.
 */
static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
{
	struct prism2_wep_data *wep = priv;
	struct blkcipher_desc desc = { .tfm = wep->rx_tfm };
	u32 klen, plen;
	u8 key[WEP_KEY_LEN + 3];
	u8 keyidx, *pos;
	u32 crc;
	u8 icv[4];
	struct scatterlist sg;

	if (skb->len < hdr_len + 8)
		return -1;

	pos = skb->data + hdr_len;
	key[0] = *pos++;
	key[1] = *pos++;
	key[2] = *pos++;
	keyidx = *pos++ >> 6;
	if (keyidx != wep->key_idx)
		return -1;

	klen = 3 + wep->key_len;

	/* Copy rest of the WEP key (the secret part) */
	memcpy(key + 3, wep->key, wep->key_len);

	/* Apply RC4 to data and compute CRC32 over decrypted data */
	plen = skb->len - hdr_len - 8;

	crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
	sg_init_one(&sg, pos, plen + 4);

	if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
		return -7;

	crc = ~crc32_le(~0, pos, plen);
	icv[0] = crc;
	icv[1] = crc >> 8;
	icv[2] = crc >> 16;
	icv[3] = crc >> 24;

	if (memcmp(icv, pos + plen, 4) != 0) {
		/* ICV mismatch - drop frame */
		return -2;
	}

	/* Remove IV and ICV */
	memmove(skb->data + 4, skb->data, hdr_len);
	skb_pull(skb, 4);
	skb_trim(skb, skb->len - 4);
	return 0;
}


static int prism2_wep_set_key(void *key, int len, u8 *seq, void *priv)
{
	struct prism2_wep_data *wep = priv;

	if (len < 0 || len > WEP_KEY_LEN)
		return -1;

	memcpy(wep->key, key, len);
	wep->key_len = len;

	return 0;
}


static int prism2_wep_get_key(void *key, int len, u8 *seq, void *priv)
{
	struct prism2_wep_data *wep = priv;

	if (len < wep->key_len)
		return -1;

	memcpy(key, wep->key, wep->key_len);

	return wep->key_len;
}


static char *prism2_wep_print_stats(char *p, void *priv)
{
	struct prism2_wep_data *wep = priv;
	p += sprintf(p, "key[%d] alg=WEP len=%d\n",
		     wep->key_idx, wep->key_len);
	return p;
}


static struct ieee80211_crypto_ops ieee80211_crypt_wep = {
	.name			= "WEP",
	.init			= prism2_wep_init,
	.deinit			= prism2_wep_deinit,
	.encrypt_mpdu		= prism2_wep_encrypt,
	.decrypt_mpdu		= prism2_wep_decrypt,
	.encrypt_msdu		= NULL,
	.decrypt_msdu		= NULL,
	.set_key		= prism2_wep_set_key,
	.get_key		= prism2_wep_get_key,
	.print_stats		= prism2_wep_print_stats,
	.extra_prefix_len	= 4, /* IV */
	.extra_postfix_len	= 4, /* ICV */
	.owner			= THIS_MODULE,
};


int ieee80211_crypto_wep_init(void)
{
	return ieee80211_register_crypto_ops(&ieee80211_crypt_wep);
}


void ieee80211_crypto_wep_exit(void)
{
	ieee80211_unregister_crypto_ops(&ieee80211_crypt_wep);
}


void ieee80211_wep_null(void)
{
//	printk("============>%s()\n", __func__);
	return;
}
Commit	Line	Data
c8d86be3 GKH	1	/*
	2	* Host AP crypt: host-based WEP encryption implementation for Host AP driver
	3	*
	4	* Copyright (c) 2002-2004, Jouni Malinen <jkmaline@cc.hut.fi>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation. See README and COPYING for
	9	* more details.
	10	*/
	11
e10fbca9 YT	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
e10fbca9 YT	13
c8d86be3	14	//#include <linux/config.h>
c8d86be3	15	#include <linux/module.h>
c8d86be3 GKH	16	#include <linux/slab.h>
	17	#include <linux/random.h>
	18	#include <linux/skbuff.h>
4de389bd	19	#include <linux/string.h>
c8d86be3 GKH	20
	21	#include "ieee80211.h"
	22
c8d86be3	23	#include <linux/crypto.h>
0370453f	24	#include <linux/scatterlist.h>
c8d86be3 GKH	25	#include <linux/crc32.h>
	26
	27	MODULE_AUTHOR("Jouni Malinen");
	28	MODULE_DESCRIPTION("Host AP crypt: WEP");
	29	MODULE_LICENSE("GPL");
	30
c8d86be3 GKH	31
	32
	33	struct prism2_wep_data {
	34	u32 iv;
	35	#define WEP_KEY_LEN 13
	36	u8 key[WEP_KEY_LEN + 1];
	37	u8 key_len;
	38	u8 key_idx;
c8d86be3 GKH	39	struct crypto_blkcipher *tx_tfm;
c8d86be3 GKH	40	struct crypto_blkcipher *rx_tfm;
c8d86be3 GKH	41	};
	42
	43
98319002	44	static void *prism2_wep_init(int keyidx)
c8d86be3 GKH	45	{
	46	struct prism2_wep_data *priv;
	47
7a6cb0d5	48	priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
c8d86be3 GKH	49	if (priv == NULL)
c8d86be3 GKH	50	goto fail;
c8d86be3	51	priv->key_idx = keyidx;
c8d86be3 GKH	52	priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
c8d86be3 GKH	53	if (IS_ERR(priv->tx_tfm)) {
e10fbca9	54	pr_debug("could not allocate crypto API arc4\n");
c8d86be3 GKH	55	priv->tx_tfm = NULL;
	56	goto fail;
	57	}
	58	priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
	59	if (IS_ERR(priv->rx_tfm)) {
e10fbca9	60	pr_debug("could not allocate crypto API arc4\n");
c8d86be3 GKH	61	priv->rx_tfm = NULL;
	62	goto fail;
	63	}
c8d86be3 GKH	64
	65	/* start WEP IV from a random value */
	66	get_random_bytes(&priv->iv, 4);
	67
	68	return priv;
	69
	70	fail:
c8d86be3 GKH	71	if (priv) {
	72	if (priv->tx_tfm)
	73	crypto_free_blkcipher(priv->tx_tfm);
	74	if (priv->rx_tfm)
	75	crypto_free_blkcipher(priv->rx_tfm);
	76	kfree(priv);
	77	}
0370453f	78
c8d86be3 GKH	79	return NULL;
	80	}
	81
	82
	83	static void prism2_wep_deinit(void *priv)
	84	{
	85	struct prism2_wep_data *_priv = priv;
0370453f	86
c8d86be3 GKH	87	if (_priv) {
	88	if (_priv->tx_tfm)
	89	crypto_free_blkcipher(_priv->tx_tfm);
	90	if (_priv->rx_tfm)
	91	crypto_free_blkcipher(_priv->rx_tfm);
	92	}
0370453f	93
c8d86be3 GKH	94	kfree(priv);
	95	}
	96
	97
	98	/* Perform WEP encryption on given skb that has at least 4 bytes of headroom
	99	* for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
	100	* so the payload length increases with 8 bytes.
	101	*
	102	* WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
	103	*/
	104	static int prism2_wep_encrypt(struct sk_buff skb, int hdr_len, void priv)
	105	{
	106	struct prism2_wep_data *wep = priv;
0370453f	107	struct blkcipher_desc desc = { .tfm = wep->tx_tfm };
c8d86be3 GKH	108	u32 klen, len;
	109	u8 key[WEP_KEY_LEN + 3];
	110	u8 *pos;
c8d86be3 GKH	111	u32 crc;
	112	u8 *icv;
	113	struct scatterlist sg;
7fdb78d0	114
c8d86be3 GKH	115	if (skb_headroom(skb) < 4 \|\| skb_tailroom(skb) < 4 \|\|
	116	skb->len < hdr_len)
	117	return -1;
	118
	119	len = skb->len - hdr_len;
	120	pos = skb_push(skb, 4);
	121	memmove(pos, pos + 4, hdr_len);
	122	pos += hdr_len;
	123
	124	klen = 3 + wep->key_len;
	125
	126	wep->iv++;
	127
	128	/* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
	129	* scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
	130	* can be used to speedup attacks, so avoid using them. */
	131	if ((wep->iv & 0xff00) == 0xff00) {
	132	u8 B = (wep->iv >> 16) & 0xff;
	133	if (B >= 3 && B < klen)
	134	wep->iv += 0x0100;
	135	}
	136
	137	/* Prepend 24-bit IV to RC4 key and TX frame */
	138	*pos++ = key[0] = (wep->iv >> 16) & 0xff;
	139	*pos++ = key[1] = (wep->iv >> 8) & 0xff;
	140	*pos++ = key[2] = wep->iv & 0xff;
	141	*pos++ = wep->key_idx << 6;
	142
	143	/* Copy rest of the WEP key (the secret part) */
	144	memcpy(key + 3, wep->key, wep->key_len);
	145
c8d86be3	146	/* Append little-endian CRC32 and encrypt it to produce ICV */
c8d86be3	147	crc = ~crc32_le(~0, pos, len);
c8d86be3 GKH	148	icv = skb_put(skb, 4);
	149	icv[0] = crc;
	150	icv[1] = crc >> 8;
	151	icv[2] = crc >> 16;
	152	icv[3] = crc >> 24;
	153
c8d86be3	154	crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
0370453f BZ	155	sg_init_one(&sg, pos, len + 4);
0370453f BZ	156
c8d86be3	157	return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
c8d86be3 GKH	158	}
	159
	160
	161	/* Perform WEP decryption on given buffer. Buffer includes whole WEP part of
	162	* the frame: IV (4 bytes), encrypted payload (including SNAP header),
	163	* ICV (4 bytes). len includes both IV and ICV.
	164	*
	165	* Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
	166	* failure. If frame is OK, IV and ICV will be removed.
	167	*/
	168	static int prism2_wep_decrypt(struct sk_buff skb, int hdr_len, void priv)
	169	{
	170	struct prism2_wep_data *wep = priv;
0370453f	171	struct blkcipher_desc desc = { .tfm = wep->rx_tfm };
c8d86be3 GKH	172	u32 klen, plen;
	173	u8 key[WEP_KEY_LEN + 3];
	174	u8 keyidx, *pos;
c8d86be3 GKH	175	u32 crc;
	176	u8 icv[4];
	177	struct scatterlist sg;
7fdb78d0	178
c8d86be3 GKH	179	if (skb->len < hdr_len + 8)
	180	return -1;
	181
	182	pos = skb->data + hdr_len;
	183	key[0] = *pos++;
	184	key[1] = *pos++;
	185	key[2] = *pos++;
	186	keyidx = *pos++ >> 6;
	187	if (keyidx != wep->key_idx)
	188	return -1;
	189
	190	klen = 3 + wep->key_len;
	191
	192	/* Copy rest of the WEP key (the secret part) */
	193	memcpy(key + 3, wep->key, wep->key_len);
	194
	195	/* Apply RC4 to data and compute CRC32 over decrypted data */
	196	plen = skb->len - hdr_len - 8;
7fdb78d0	197
c8d86be3	198	crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
0370453f BZ	199	sg_init_one(&sg, pos, plen + 4);
0370453f BZ	200
c8d86be3 GKH	201	if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
c8d86be3 GKH	202	return -7;
c8d86be3	203
c8d86be3	204	crc = ~crc32_le(~0, pos, plen);
c8d86be3 GKH	205	icv[0] = crc;
	206	icv[1] = crc >> 8;
	207	icv[2] = crc >> 16;
	208	icv[3] = crc >> 24;
	209
	210	if (memcmp(icv, pos + plen, 4) != 0) {
	211	/* ICV mismatch - drop frame */
	212	return -2;
	213	}
c8d86be3 GKH	214
	215	/* Remove IV and ICV */
	216	memmove(skb->data + 4, skb->data, hdr_len);
	217	skb_pull(skb, 4);
	218	skb_trim(skb, skb->len - 4);
0ef68ab4	219	return 0;
c8d86be3 GKH	220	}
	221
	222
	223	static int prism2_wep_set_key(void key, int len, u8 seq, void *priv)
	224	{
	225	struct prism2_wep_data *wep = priv;
	226
	227	if (len < 0 \|\| len > WEP_KEY_LEN)
	228	return -1;
	229
	230	memcpy(wep->key, key, len);
	231	wep->key_len = len;
	232
	233	return 0;
	234	}
	235
	236
	237	static int prism2_wep_get_key(void key, int len, u8 seq, void *priv)
	238	{
	239	struct prism2_wep_data *wep = priv;
	240
	241	if (len < wep->key_len)
	242	return -1;
	243
	244	memcpy(key, wep->key, wep->key_len);
	245
	246	return wep->key_len;
	247	}
	248
	249
98319002	250	static char prism2_wep_print_stats(char p, void *priv)
c8d86be3 GKH	251	{
	252	struct prism2_wep_data *wep = priv;
	253	p += sprintf(p, "key[%d] alg=WEP len=%d\n",
	254	wep->key_idx, wep->key_len);
	255	return p;
	256	}
	257
	258
	259	static struct ieee80211_crypto_ops ieee80211_crypt_wep = {
	260	.name = "WEP",
	261	.init = prism2_wep_init,
	262	.deinit = prism2_wep_deinit,
	263	.encrypt_mpdu = prism2_wep_encrypt,
	264	.decrypt_mpdu = prism2_wep_decrypt,
	265	.encrypt_msdu = NULL,
	266	.decrypt_msdu = NULL,
	267	.set_key = prism2_wep_set_key,
	268	.get_key = prism2_wep_get_key,
	269	.print_stats = prism2_wep_print_stats,
	270	.extra_prefix_len = 4, /* IV */
	271	.extra_postfix_len = 4, /* ICV */
	272	.owner = THIS_MODULE,
	273	};
	274
	275
	276	int ieee80211_crypto_wep_init(void)
	277	{
	278	return ieee80211_register_crypto_ops(&ieee80211_crypt_wep);
	279	}
	280
	281
	282	void ieee80211_crypto_wep_exit(void)
	283	{
	284	ieee80211_unregister_crypto_ops(&ieee80211_crypt_wep);
	285	}
	286
	287
	288	void ieee80211_wep_null(void)
	289	{
d599edca	290	// printk("============>%s()\n", __func__);
0ef68ab4	291	return;
c8d86be3	292	}