[mirror_ubuntu-artful-kernel.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)) {
		pr_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)) {
		pr_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){
		pr_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 void prism2_wep_print_stats(struct seq_file *m, void *priv)
{
	struct prism2_wep_data *wep = priv;

	seq_printf(m, "key[%d] alg=WEP len=%d\n", wep->key_idx, wep->key_len);
}

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,
};


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


static 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	46	if (IS_ERR(priv->tx_tfm)) {
0822339b	47	pr_debug("rtllib_crypt_wep: could not allocate crypto API arc4\n");
a44325f9 LF	48	priv->tx_tfm = NULL;
	49	goto fail;
	50	}
	51	priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
	52	if (IS_ERR(priv->rx_tfm)) {
0822339b	53	pr_debug("rtllib_crypt_wep: could not allocate crypto API arc4\n");
a44325f9 LF	54	priv->rx_tfm = NULL;
	55	goto fail;
	56	}
ecdfa446 GKH	57
	58	/* start WEP IV from a random value */
	59	get_random_bytes(&priv->iv, 4);
	60
	61	return priv;
	62
	63	fail:
ecdfa446	64	if (priv) {
a44325f9 LF	65	if (priv->tx_tfm)
	66	crypto_free_blkcipher(priv->tx_tfm);
	67	if (priv->rx_tfm)
	68	crypto_free_blkcipher(priv->rx_tfm);
	69	kfree(priv);
	70	}
ecdfa446 GKH	71	return NULL;
	72	}
	73
	74
	75	static void prism2_wep_deinit(void *priv)
	76	{
	77	struct prism2_wep_data *_priv = priv;
cb762154	78
ecdfa446	79	if (_priv) {
a44325f9 LF	80	if (_priv->tx_tfm)
	81	crypto_free_blkcipher(_priv->tx_tfm);
	82	if (_priv->rx_tfm)
	83	crypto_free_blkcipher(_priv->rx_tfm);
	84	}
ecdfa446 GKH	85	kfree(priv);
	86	}
	87
	88	/* Perform WEP encryption on given skb that has at least 4 bytes of headroom
	89	* for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
	90	* so the payload length increases with 8 bytes.
	91	*
	92	* WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
	93	*/
	94	static int prism2_wep_encrypt(struct sk_buff skb, int hdr_len, void priv)
	95	{
	96	struct prism2_wep_data *wep = priv;
	97	u32 klen, len;
	98	u8 key[WEP_KEY_LEN + 3];
	99	u8 *pos;
a44325f9 LF	100	struct cb_desc tcb_desc = (struct cb_desc )(skb->cb +
a44325f9 LF	101	MAX_DEV_ADDR_SIZE);
ecdfa446	102	struct blkcipher_desc desc = {.tfm = wep->tx_tfm};
ecdfa446 GKH	103	u32 crc;
	104	u8 *icv;
	105	struct scatterlist sg;
3a6b70c3	106
ecdfa446	107	if (skb_headroom(skb) < 4 \|\| skb_tailroom(skb) < 4 \|\|
94a79942	108	skb->len < hdr_len){
d69d2054	109	pr_err("Error!!! headroom=%d tailroom=%d skblen=%d hdr_len=%d\n",
0822339b	110	skb_headroom(skb), skb_tailroom(skb), skb->len, hdr_len);
ecdfa446	111	return -1;
94a79942	112	}
ecdfa446 GKH	113	len = skb->len - hdr_len;
	114	pos = skb_push(skb, 4);
	115	memmove(pos, pos + 4, hdr_len);
	116	pos += hdr_len;
	117
	118	klen = 3 + wep->key_len;
	119
	120	wep->iv++;
	121
	122	/* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
	123	* scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
14b40d92 MK	124	* can be used to speedup attacks, so avoid using them.
14b40d92 MK	125	*/
ecdfa446 GKH	126	if ((wep->iv & 0xff00) == 0xff00) {
ecdfa446 GKH	127	u8 B = (wep->iv >> 16) & 0xff;
3a6b70c3	128
ecdfa446 GKH	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;
3a6b70c3	180
ecdfa446 GKH	181	if (skb->len < hdr_len + 8)
	182	return -1;
	183
	184	pos = skb->data + hdr_len;
	185	key[0] = *pos++;
	186	key[1] = *pos++;
	187	key[2] = *pos++;
	188	keyidx = *pos++ >> 6;
	189	if (keyidx != wep->key_idx)
	190	return -1;
	191
	192	klen = 3 + wep->key_len;
	193
	194	/* Copy rest of the WEP key (the secret part) */
	195	memcpy(key + 3, wep->key, wep->key_len);
	196
	197	/* Apply RC4 to data and compute CRC32 over decrypted data */
	198	plen = skb->len - hdr_len - 8;
	199
cb762154	200	if (!tcb_desc->bHwSec) {
ecdfa446	201	sg_init_one(&sg, pos, plen+4);
94a79942	202	crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
ecdfa446 GKH	203	if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
ecdfa446 GKH	204	return -7;
ecdfa446	205	crc = ~crc32_le(~0, pos, plen);
ecdfa446 GKH	206	icv[0] = crc;
	207	icv[1] = crc >> 8;
	208	icv[2] = crc >> 16;
	209	icv[3] = crc >> 24;
	210	if (memcmp(icv, pos + plen, 4) != 0) {
	211	/* ICV mismatch - drop frame */
	212	return -2;
	213	}
	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);
	219
	220	return 0;
	221	}
	222
	223
	224	static int prism2_wep_set_key(void key, int len, u8 seq, void *priv)
	225	{
	226	struct prism2_wep_data *wep = priv;
	227
	228	if (len < 0 \|\| len > WEP_KEY_LEN)
	229	return -1;
	230
	231	memcpy(wep->key, key, len);
	232	wep->key_len = len;
	233
	234	return 0;
	235	}
	236
	237
	238	static int prism2_wep_get_key(void key, int len, u8 seq, void *priv)
	239	{
	240	struct prism2_wep_data *wep = priv;
	241
	242	if (len < wep->key_len)
	243	return -1;
	244
	245	memcpy(key, wep->key, wep->key_len);
	246
	247	return wep->key_len;
	248	}
	249
	250
6bbefe86	251	static void prism2_wep_print_stats(struct seq_file m, void priv)
ecdfa446 GKH	252	{
ecdfa446 GKH	253	struct prism2_wep_data *wep = priv;
3a6b70c3	254
6bbefe86	255	seq_printf(m, "key[%d] alg=WEP len=%d\n", wep->key_idx, wep->key_len);
ecdfa446 GKH	256	}
ecdfa446 GKH	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
20fc5afc	275	static int __init rtllib_crypto_wep_init(void)
ecdfa446	276	{
3b148be0	277	return lib80211_register_crypto_ops(&rtllib_crypt_wep);
ecdfa446 GKH	278	}
	279
	280
20fc5afc	281	static 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");