2 * Host AP crypt: host-based WEP encryption implementation for Host AP driver
4 * Copyright (c) 2002-2004, Jouni Malinen <jkmaline@cc.hut.fi>
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
12 //#include <linux/config.h>
13 #include <linux/version.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/slab.h>
17 #include <linux/random.h>
18 #include <linux/skbuff.h>
19 #include <asm/string.h>
21 #include "ieee80211.h"
24 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
25 #include "rtl_crypto.h"
27 #include <linux/crypto.h>
30 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
31 #include <asm/scatterlist.h>
33 #include <linux/scatterlist.h>
35 //#include <asm/scatterlist.h>
36 #include <linux/crc32.h>
39 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
40 #include "rtl_crypto.h"
42 #include <linux/crypto.h>
45 #include <asm/scatterlist.h>
46 #include <linux/crc32.h>
48 MODULE_AUTHOR("Jouni Malinen");
49 MODULE_DESCRIPTION("Host AP crypt: WEP");
50 MODULE_LICENSE("GPL");
52 #define OPENSUSE_SLED 0
55 struct prism2_wep_data {
57 #define WEP_KEY_LEN 13
58 u8 key[WEP_KEY_LEN + 1];
61 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
62 struct crypto_tfm *tfm;
64 struct crypto_blkcipher *tx_tfm;
65 struct crypto_blkcipher *rx_tfm;
70 static void * prism2_wep_init(int keyidx)
72 struct prism2_wep_data *priv;
74 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
77 priv->key_idx = keyidx;
79 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
80 priv->tfm = crypto_alloc_tfm("arc4", 0);
81 if (priv->tfm == NULL) {
82 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
87 priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
88 if (IS_ERR(priv->tx_tfm)) {
89 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
94 priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
95 if (IS_ERR(priv->rx_tfm)) {
96 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
103 /* start WEP IV from a random value */
104 get_random_bytes(&priv->iv, 4);
109 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
112 crypto_free_tfm(priv->tfm);
118 crypto_free_blkcipher(priv->tx_tfm);
120 crypto_free_blkcipher(priv->rx_tfm);
128 static void prism2_wep_deinit(void *priv)
130 struct prism2_wep_data *_priv = priv;
131 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
132 if (_priv && _priv->tfm)
133 crypto_free_tfm(_priv->tfm);
137 crypto_free_blkcipher(_priv->tx_tfm);
139 crypto_free_blkcipher(_priv->rx_tfm);
145 /* Perform WEP encryption on given skb that has at least 4 bytes of headroom
146 * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
147 * so the payload length increases with 8 bytes.
149 * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
151 static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
153 struct prism2_wep_data *wep = priv;
155 u8 key[WEP_KEY_LEN + 3];
157 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
158 #if((LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)) || (OPENSUSE_SLED))
159 struct blkcipher_desc desc = {.tfm = wep->tx_tfm};
163 struct scatterlist sg;
164 if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
168 len = skb->len - hdr_len;
169 pos = skb_push(skb, 4);
170 memmove(pos, pos + 4, hdr_len);
173 klen = 3 + wep->key_len;
177 /* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
178 * scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
179 * can be used to speedup attacks, so avoid using them. */
180 if ((wep->iv & 0xff00) == 0xff00) {
181 u8 B = (wep->iv >> 16) & 0xff;
182 if (B >= 3 && B < klen)
186 /* Prepend 24-bit IV to RC4 key and TX frame */
187 *pos++ = key[0] = (wep->iv >> 16) & 0xff;
188 *pos++ = key[1] = (wep->iv >> 8) & 0xff;
189 *pos++ = key[2] = wep->iv & 0xff;
190 *pos++ = wep->key_idx << 6;
192 /* Copy rest of the WEP key (the secret part) */
193 memcpy(key + 3, wep->key, wep->key_len);
195 if (!tcb_desc->bHwSec)
198 /* Append little-endian CRC32 and encrypt it to produce ICV */
199 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
200 crc = ~crc32_le(~0, pos, len);
202 crc = ~ether_crc_le(len, pos);
204 icv = skb_put(skb, 4);
210 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
211 crypto_cipher_setkey(wep->tfm, key, klen);
212 sg.page = virt_to_page(pos);
213 sg.offset = offset_in_page(pos);
215 crypto_cipher_encrypt(wep->tfm, &sg, &sg, len + 4);
218 crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
219 #if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24))
220 sg.page = virt_to_page(pos);
221 sg.offset = offset_in_page(pos);
224 sg_init_one(&sg, pos, len+4);
226 return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
234 /* Perform WEP decryption on given buffer. Buffer includes whole WEP part of
235 * the frame: IV (4 bytes), encrypted payload (including SNAP header),
236 * ICV (4 bytes). len includes both IV and ICV.
238 * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
239 * failure. If frame is OK, IV and ICV will be removed.
241 static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
243 struct prism2_wep_data *wep = priv;
245 u8 key[WEP_KEY_LEN + 3];
247 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
248 #if((LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)) || (OPENSUSE_SLED))
249 struct blkcipher_desc desc = {.tfm = wep->rx_tfm};
253 struct scatterlist sg;
254 if (skb->len < hdr_len + 8)
257 pos = skb->data + hdr_len;
261 keyidx = *pos++ >> 6;
262 if (keyidx != wep->key_idx)
265 klen = 3 + wep->key_len;
267 /* Copy rest of the WEP key (the secret part) */
268 memcpy(key + 3, wep->key, wep->key_len);
270 /* Apply RC4 to data and compute CRC32 over decrypted data */
271 plen = skb->len - hdr_len - 8;
273 if (!tcb_desc->bHwSec)
275 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
276 crypto_cipher_setkey(wep->tfm, key, klen);
277 sg.page = virt_to_page(pos);
278 sg.offset = offset_in_page(pos);
279 sg.length = plen + 4;
280 crypto_cipher_decrypt(wep->tfm, &sg, &sg, plen + 4);
282 crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
283 #if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24))
284 sg.page = virt_to_page(pos);
285 sg.offset = offset_in_page(pos);
286 sg.length = plen + 4;
288 sg_init_one(&sg, pos, plen+4);
290 if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
293 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
294 crc = ~crc32_le(~0, pos, plen);
296 crc = ~ether_crc_le(plen, pos);
302 if (memcmp(icv, pos + plen, 4) != 0) {
303 /* ICV mismatch - drop frame */
307 /* Remove IV and ICV */
308 memmove(skb->data + 4, skb->data, hdr_len);
310 skb_trim(skb, skb->len - 4);
316 static int prism2_wep_set_key(void *key, int len, u8 *seq, void *priv)
318 struct prism2_wep_data *wep = priv;
320 if (len < 0 || len > WEP_KEY_LEN)
323 memcpy(wep->key, key, len);
330 static int prism2_wep_get_key(void *key, int len, u8 *seq, void *priv)
332 struct prism2_wep_data *wep = priv;
334 if (len < wep->key_len)
337 memcpy(key, wep->key, wep->key_len);
343 static char * prism2_wep_print_stats(char *p, void *priv)
345 struct prism2_wep_data *wep = priv;
346 p += sprintf(p, "key[%d] alg=WEP len=%d\n",
347 wep->key_idx, wep->key_len);
352 static struct ieee80211_crypto_ops ieee80211_crypt_wep = {
354 .init = prism2_wep_init,
355 .deinit = prism2_wep_deinit,
356 .encrypt_mpdu = prism2_wep_encrypt,
357 .decrypt_mpdu = prism2_wep_decrypt,
358 .encrypt_msdu = NULL,
359 .decrypt_msdu = NULL,
360 .set_key = prism2_wep_set_key,
361 .get_key = prism2_wep_get_key,
362 .print_stats = prism2_wep_print_stats,
363 .extra_prefix_len = 4, /* IV */
364 .extra_postfix_len = 4, /* ICV */
365 .owner = THIS_MODULE,
369 int __init ieee80211_crypto_wep_init(void)
371 return ieee80211_register_crypto_ops(&ieee80211_crypt_wep);
375 void __exit ieee80211_crypto_wep_exit(void)
377 ieee80211_unregister_crypto_ops(&ieee80211_crypt_wep);
380 void ieee80211_wep_null(void)
382 // printk("============>%s()\n", __FUNCTION__);
385 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
386 //EXPORT_SYMBOL(ieee80211_wep_null);
388 EXPORT_SYMBOL_NOVERS(ieee80211_wep_null);
391 //module_init(ieee80211_crypto_wep_init);
392 //module_exit(ieee80211_crypto_wep_exit);