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 = kmalloc(sizeof(*priv), GFP_ATOMIC);
77 memset(priv, 0, sizeof(*priv));
78 priv->key_idx = keyidx;
80 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
81 priv->tfm = crypto_alloc_tfm("arc4", 0);
82 if (priv->tfm == NULL) {
83 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
88 priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
89 if (IS_ERR(priv->tx_tfm)) {
90 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
95 priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
96 if (IS_ERR(priv->rx_tfm)) {
97 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
104 /* start WEP IV from a random value */
105 get_random_bytes(&priv->iv, 4);
110 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
113 crypto_free_tfm(priv->tfm);
119 crypto_free_blkcipher(priv->tx_tfm);
121 crypto_free_blkcipher(priv->rx_tfm);
129 static void prism2_wep_deinit(void *priv)
131 struct prism2_wep_data *_priv = priv;
132 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
133 if (_priv && _priv->tfm)
134 crypto_free_tfm(_priv->tfm);
138 crypto_free_blkcipher(_priv->tx_tfm);
140 crypto_free_blkcipher(_priv->rx_tfm);
146 /* Perform WEP encryption on given skb that has at least 4 bytes of headroom
147 * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
148 * so the payload length increases with 8 bytes.
150 * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
152 static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
154 struct prism2_wep_data *wep = priv;
156 u8 key[WEP_KEY_LEN + 3];
158 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
159 #if((LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)) || (OPENSUSE_SLED))
160 struct blkcipher_desc desc = {.tfm = wep->tx_tfm};
164 struct scatterlist sg;
165 if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
169 len = skb->len - hdr_len;
170 pos = skb_push(skb, 4);
171 memmove(pos, pos + 4, hdr_len);
174 klen = 3 + wep->key_len;
178 /* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
179 * scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
180 * can be used to speedup attacks, so avoid using them. */
181 if ((wep->iv & 0xff00) == 0xff00) {
182 u8 B = (wep->iv >> 16) & 0xff;
183 if (B >= 3 && B < klen)
187 /* Prepend 24-bit IV to RC4 key and TX frame */
188 *pos++ = key[0] = (wep->iv >> 16) & 0xff;
189 *pos++ = key[1] = (wep->iv >> 8) & 0xff;
190 *pos++ = key[2] = wep->iv & 0xff;
191 *pos++ = wep->key_idx << 6;
193 /* Copy rest of the WEP key (the secret part) */
194 memcpy(key + 3, wep->key, wep->key_len);
196 if (!tcb_desc->bHwSec)
199 /* Append little-endian CRC32 and encrypt it to produce ICV */
200 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
201 crc = ~crc32_le(~0, pos, len);
203 crc = ~ether_crc_le(len, pos);
205 icv = skb_put(skb, 4);
211 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
212 crypto_cipher_setkey(wep->tfm, key, klen);
213 sg.page = virt_to_page(pos);
214 sg.offset = offset_in_page(pos);
216 crypto_cipher_encrypt(wep->tfm, &sg, &sg, len + 4);
219 crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
220 #if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24))
221 sg.page = virt_to_page(pos);
222 sg.offset = offset_in_page(pos);
225 sg_init_one(&sg, pos, len+4);
227 return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
235 /* Perform WEP decryption on given buffer. Buffer includes whole WEP part of
236 * the frame: IV (4 bytes), encrypted payload (including SNAP header),
237 * ICV (4 bytes). len includes both IV and ICV.
239 * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
240 * failure. If frame is OK, IV and ICV will be removed.
242 static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
244 struct prism2_wep_data *wep = priv;
246 u8 key[WEP_KEY_LEN + 3];
248 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
249 #if((LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)) || (OPENSUSE_SLED))
250 struct blkcipher_desc desc = {.tfm = wep->rx_tfm};
254 struct scatterlist sg;
255 if (skb->len < hdr_len + 8)
258 pos = skb->data + hdr_len;
262 keyidx = *pos++ >> 6;
263 if (keyidx != wep->key_idx)
266 klen = 3 + wep->key_len;
268 /* Copy rest of the WEP key (the secret part) */
269 memcpy(key + 3, wep->key, wep->key_len);
271 /* Apply RC4 to data and compute CRC32 over decrypted data */
272 plen = skb->len - hdr_len - 8;
274 if (!tcb_desc->bHwSec)
276 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
277 crypto_cipher_setkey(wep->tfm, key, klen);
278 sg.page = virt_to_page(pos);
279 sg.offset = offset_in_page(pos);
280 sg.length = plen + 4;
281 crypto_cipher_decrypt(wep->tfm, &sg, &sg, plen + 4);
283 crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
284 #if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24))
285 sg.page = virt_to_page(pos);
286 sg.offset = offset_in_page(pos);
287 sg.length = plen + 4;
289 sg_init_one(&sg, pos, plen+4);
291 if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
294 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
295 crc = ~crc32_le(~0, pos, plen);
297 crc = ~ether_crc_le(plen, pos);
303 if (memcmp(icv, pos + plen, 4) != 0) {
304 /* ICV mismatch - drop frame */
308 /* Remove IV and ICV */
309 memmove(skb->data + 4, skb->data, hdr_len);
311 skb_trim(skb, skb->len - 4);
317 static int prism2_wep_set_key(void *key, int len, u8 *seq, void *priv)
319 struct prism2_wep_data *wep = priv;
321 if (len < 0 || len > WEP_KEY_LEN)
324 memcpy(wep->key, key, len);
331 static int prism2_wep_get_key(void *key, int len, u8 *seq, void *priv)
333 struct prism2_wep_data *wep = priv;
335 if (len < wep->key_len)
338 memcpy(key, wep->key, wep->key_len);
344 static char * prism2_wep_print_stats(char *p, void *priv)
346 struct prism2_wep_data *wep = priv;
347 p += sprintf(p, "key[%d] alg=WEP len=%d\n",
348 wep->key_idx, wep->key_len);
353 static struct ieee80211_crypto_ops ieee80211_crypt_wep = {
355 .init = prism2_wep_init,
356 .deinit = prism2_wep_deinit,
357 .encrypt_mpdu = prism2_wep_encrypt,
358 .decrypt_mpdu = prism2_wep_decrypt,
359 .encrypt_msdu = NULL,
360 .decrypt_msdu = NULL,
361 .set_key = prism2_wep_set_key,
362 .get_key = prism2_wep_get_key,
363 .print_stats = prism2_wep_print_stats,
364 .extra_prefix_len = 4, /* IV */
365 .extra_postfix_len = 4, /* ICV */
366 .owner = THIS_MODULE,
370 int __init ieee80211_crypto_wep_init(void)
372 return ieee80211_register_crypto_ops(&ieee80211_crypt_wep);
376 void __exit ieee80211_crypto_wep_exit(void)
378 ieee80211_unregister_crypto_ops(&ieee80211_crypt_wep);
381 void ieee80211_wep_null(void)
383 // printk("============>%s()\n", __FUNCTION__);
386 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
387 //EXPORT_SYMBOL(ieee80211_wep_null);
389 EXPORT_SYMBOL_NOVERS(ieee80211_wep_null);
392 //module_init(ieee80211_crypto_wep_init);
393 //module_exit(ieee80211_crypto_wep_exit);