[deliverable/linux.git] / drivers / staging / rtl8192e / rtllib_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.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/skbuff.h>
#include <linux/string.h>
#include "rtllib.h"

#include <linux/crypto.h>

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

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)) {
		printk(KERN_DEBUG "rtllib_crypt_wep: 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)) {
		printk(KERN_DEBUG "rtllib_crypt_wep: 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;
	u32 klen, len;
	u8 key[WEP_KEY_LEN + 3];
	u8 *pos;
	struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb +
				    MAX_DEV_ADDR_SIZE);
	struct blkcipher_desc desc = {.tfm = wep->tx_tfm};
	u32 crc;
	u8 *icv;
	struct scatterlist sg;
	if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
	    skb->len < hdr_len){
		printk(KERN_ERR "Error!!! headroom=%d tailroom=%d skblen=%d"
		       " hdr_len=%d\n", skb_headroom(skb), skb_tailroom(skb),
		       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);

	if (!tcb_desc->bHwSec) {

		/* 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;

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

	return 0;
}


/* Perform WEP decryption on given struct 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;
	u32  klen, plen;
	u8 key[WEP_KEY_LEN + 3];
	u8 keyidx, *pos;
	struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb +
				    MAX_DEV_ADDR_SIZE);
	struct blkcipher_desc desc = {.tfm = wep->rx_tfm};
	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;

	if (!tcb_desc->bHwSec) {
		sg_init_one(&sg, pos, plen+4);
		crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
		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 lib80211_crypto_ops rtllib_crypt_wep = {
	.name			= "R-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_mpdu_prefix_len  = 4,	/* IV */
	.extra_mpdu_postfix_len = 4,	/* ICV */
	.owner			= THIS_MODULE,
};


int __init rtllib_crypto_wep_init(void)
{
	return lib80211_register_crypto_ops(&rtllib_crypt_wep);
}


void __exit rtllib_crypto_wep_exit(void)
{
	lib80211_unregister_crypto_ops(&rtllib_crypt_wep);
}

module_init(rtllib_crypto_wep_init);
module_exit(rtllib_crypto_wep_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
ecdfa446 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
ecdfa446 GKH	12	#include <linux/module.h>
	13	#include <linux/init.h>
	14	#include <linux/slab.h>
	15	#include <linux/random.h>
	16	#include <linux/skbuff.h>
a44325f9	17	#include <linux/string.h>
94a79942	18	#include "rtllib.h"
ecdfa446	19
ecdfa446	20	#include <linux/crypto.h>
ecdfa446	21
cb762154	22	#include <linux/scatterlist.h>
ecdfa446	23	#include <linux/crc32.h>
ecdfa446 GKH	24
	25	struct prism2_wep_data {
	26	u32 iv;
	27	#define WEP_KEY_LEN 13
	28	u8 key[WEP_KEY_LEN + 1];
	29	u8 key_len;
	30	u8 key_idx;
a44325f9 LF	31	struct crypto_blkcipher *tx_tfm;
a44325f9 LF	32	struct crypto_blkcipher *rx_tfm;
ecdfa446 GKH	33	};
	34
	35
a44325f9	36	static void *prism2_wep_init(int keyidx)
ecdfa446 GKH	37	{
	38	struct prism2_wep_data *priv;
	39
929fa2a4	40	priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
ecdfa446 GKH	41	if (priv == NULL)
ecdfa446 GKH	42	goto fail;
ecdfa446 GKH	43	priv->key_idx = keyidx;
ecdfa446 GKH	44
ecdfa446	45	priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
a44325f9 LF	46	if (IS_ERR(priv->tx_tfm)) {
	47	printk(KERN_DEBUG "rtllib_crypt_wep: could not allocate "
	48	"crypto API arc4\n");
	49	priv->tx_tfm = NULL;
	50	goto fail;
	51	}
	52	priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
	53	if (IS_ERR(priv->rx_tfm)) {
	54	printk(KERN_DEBUG "rtllib_crypt_wep: could not allocate "
	55	"crypto API arc4\n");
	56	priv->rx_tfm = NULL;
	57	goto fail;
	58	}
ecdfa446 GKH	59
	60	/* start WEP IV from a random value */
	61	get_random_bytes(&priv->iv, 4);
	62
	63	return priv;
	64
	65	fail:
ecdfa446	66	if (priv) {
a44325f9 LF	67	if (priv->tx_tfm)
	68	crypto_free_blkcipher(priv->tx_tfm);
	69	if (priv->rx_tfm)
	70	crypto_free_blkcipher(priv->rx_tfm);
	71	kfree(priv);
	72	}
ecdfa446 GKH	73	return NULL;
	74	}
	75
	76
	77	static void prism2_wep_deinit(void *priv)
	78	{
	79	struct prism2_wep_data *_priv = priv;
cb762154	80
ecdfa446	81	if (_priv) {
a44325f9 LF	82	if (_priv->tx_tfm)
	83	crypto_free_blkcipher(_priv->tx_tfm);
	84	if (_priv->rx_tfm)
	85	crypto_free_blkcipher(_priv->rx_tfm);
	86	}
ecdfa446 GKH	87	kfree(priv);
	88	}
	89
	90	/* Perform WEP encryption on given skb that has at least 4 bytes of headroom
	91	* for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
	92	* so the payload length increases with 8 bytes.
	93	*
	94	* WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
	95	*/
	96	static int prism2_wep_encrypt(struct sk_buff skb, int hdr_len, void priv)
	97	{
	98	struct prism2_wep_data *wep = priv;
	99	u32 klen, len;
	100	u8 key[WEP_KEY_LEN + 3];
	101	u8 *pos;
a44325f9 LF	102	struct cb_desc tcb_desc = (struct cb_desc )(skb->cb +
a44325f9 LF	103	MAX_DEV_ADDR_SIZE);
ecdfa446	104	struct blkcipher_desc desc = {.tfm = wep->tx_tfm};
ecdfa446 GKH	105	u32 crc;
	106	u8 *icv;
	107	struct scatterlist sg;
	108	if (skb_headroom(skb) < 4 \|\| skb_tailroom(skb) < 4 \|\|
94a79942	109	skb->len < hdr_len){
a44325f9 LF	110	printk(KERN_ERR "Error!!! headroom=%d tailroom=%d skblen=%d"
	111	" hdr_len=%d\n", skb_headroom(skb), skb_tailroom(skb),
	112	skb->len, hdr_len);
ecdfa446	113	return -1;
94a79942	114	}
ecdfa446 GKH	115	len = skb->len - hdr_len;
	116	pos = skb_push(skb, 4);
	117	memmove(pos, pos + 4, hdr_len);
	118	pos += hdr_len;
	119
	120	klen = 3 + wep->key_len;
	121
	122	wep->iv++;
	123
	124	/* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
	125	* scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
	126	* can be used to speedup attacks, so avoid using them. */
	127	if ((wep->iv & 0xff00) == 0xff00) {
	128	u8 B = (wep->iv >> 16) & 0xff;
	129	if (B >= 3 && B < klen)
	130	wep->iv += 0x0100;
	131	}
	132
	133	/* Prepend 24-bit IV to RC4 key and TX frame */
	134	*pos++ = key[0] = (wep->iv >> 16) & 0xff;
	135	*pos++ = key[1] = (wep->iv >> 8) & 0xff;
	136	*pos++ = key[2] = wep->iv & 0xff;
	137	*pos++ = wep->key_idx << 6;
	138
	139	/* Copy rest of the WEP key (the secret part) */
	140	memcpy(key + 3, wep->key, wep->key_len);
	141
cb762154	142	if (!tcb_desc->bHwSec) {
ecdfa446 GKH	143
ecdfa446 GKH	144	/* Append little-endian CRC32 and encrypt it to produce ICV */
ecdfa446	145	crc = ~crc32_le(~0, pos, len);
ecdfa446 GKH	146	icv = skb_put(skb, 4);
	147	icv[0] = crc;
	148	icv[1] = crc >> 8;
	149	icv[2] = crc >> 16;
	150	icv[3] = crc >> 24;
	151
ecdfa446	152	sg_init_one(&sg, pos, len+4);
94a79942	153	crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
ecdfa446	154	return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
ecdfa446 GKH	155	}
	156
	157	return 0;
	158	}
	159
	160
a44325f9 LF	161	/* Perform WEP decryption on given struct buffer. Buffer includes whole WEP
a44325f9 LF	162	* part of the frame: IV (4 bytes), encrypted payload (including SNAP header),
ecdfa446 GKH	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;
	171	u32 klen, plen;
	172	u8 key[WEP_KEY_LEN + 3];
	173	u8 keyidx, *pos;
a44325f9 LF	174	struct cb_desc tcb_desc = (struct cb_desc )(skb->cb +
a44325f9 LF	175	MAX_DEV_ADDR_SIZE);
ecdfa446	176	struct blkcipher_desc desc = {.tfm = wep->rx_tfm};
ecdfa446 GKH	177	u32 crc;
	178	u8 icv[4];
	179	struct scatterlist sg;
	180	if (skb->len < hdr_len + 8)
	181	return -1;
	182
	183	pos = skb->data + hdr_len;
	184	key[0] = *pos++;
	185	key[1] = *pos++;
	186	key[2] = *pos++;
	187	keyidx = *pos++ >> 6;
	188	if (keyidx != wep->key_idx)
	189	return -1;
	190
	191	klen = 3 + wep->key_len;
	192
	193	/* Copy rest of the WEP key (the secret part) */
	194	memcpy(key + 3, wep->key, wep->key_len);
	195
	196	/* Apply RC4 to data and compute CRC32 over decrypted data */
	197	plen = skb->len - hdr_len - 8;
	198
cb762154	199	if (!tcb_desc->bHwSec) {
ecdfa446	200	sg_init_one(&sg, pos, plen+4);
94a79942	201	crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
ecdfa446 GKH	202	if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
ecdfa446 GKH	203	return -7;
ecdfa446	204	crc = ~crc32_le(~0, pos, plen);
ecdfa446 GKH	205	icv[0] = crc;
	206	icv[1] = crc >> 8;
	207	icv[2] = crc >> 16;
	208	icv[3] = crc >> 24;
	209	if (memcmp(icv, pos + plen, 4) != 0) {
	210	/* ICV mismatch - drop frame */
	211	return -2;
	212	}
	213	}
	214	/* Remove IV and ICV */
	215	memmove(skb->data + 4, skb->data, hdr_len);
	216	skb_pull(skb, 4);
	217	skb_trim(skb, skb->len - 4);
	218
	219	return 0;
	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
a44325f9	250	static char prism2_wep_print_stats(char p, void *priv)
ecdfa446 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
32c44cb5	258	static struct lib80211_crypto_ops rtllib_crypt_wep = {
3b148be0	259	.name = "R-WEP",
ecdfa446 GKH	260	.init = prism2_wep_init,
	261	.deinit = prism2_wep_deinit,
	262	.encrypt_mpdu = prism2_wep_encrypt,
	263	.decrypt_mpdu = prism2_wep_decrypt,
	264	.encrypt_msdu = NULL,
	265	.decrypt_msdu = NULL,
	266	.set_key = prism2_wep_set_key,
	267	.get_key = prism2_wep_get_key,
	268	.print_stats = prism2_wep_print_stats,
32c44cb5 SM	269	.extra_mpdu_prefix_len = 4, /* IV */
32c44cb5 SM	270	.extra_mpdu_postfix_len = 4, /* ICV */
ecdfa446 GKH	271	.owner = THIS_MODULE,
	272	};
	273
	274
94a79942	275	int __init rtllib_crypto_wep_init(void)
ecdfa446	276	{
3b148be0	277	return lib80211_register_crypto_ops(&rtllib_crypt_wep);
ecdfa446 GKH	278	}
	279
	280
94a79942	281	void __exit rtllib_crypto_wep_exit(void)
ecdfa446	282	{
3b148be0	283	lib80211_unregister_crypto_ops(&rtllib_crypt_wep);
ecdfa446 GKH	284	}
ecdfa446 GKH	285
d37e0208 SM	286	module_init(rtllib_crypto_wep_init);
	287	module_exit(rtllib_crypto_wep_exit);
	288
	289	MODULE_LICENSE("GPL");