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"
23 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
24 #include "rtl_crypto.h"
26 #include <linux/crypto.h>
29 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
30 #include <asm/scatterlist.h>
32 #include <linux/scatterlist.h>
34 //#include <asm/scatterlist.h>
35 #include <linux/crc32.h>
37 MODULE_AUTHOR("Jouni Malinen");
38 MODULE_DESCRIPTION("Host AP crypt: WEP");
39 MODULE_LICENSE("GPL");
42 #ifndef IN_OPENSUSE_SLED
43 #define IN_OPENSUSE_SLED 1
48 struct prism2_wep_data {
50 #define WEP_KEY_LEN 13
51 u8 key[WEP_KEY_LEN + 1];
54 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))&&(!IN_OPENSUSE_SLED))
55 struct crypto_tfm *tfm;
57 struct crypto_blkcipher *tx_tfm;
58 struct crypto_blkcipher *rx_tfm;
63 static void * prism2_wep_init(int keyidx)
65 struct prism2_wep_data *priv;
67 priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
70 memset(priv, 0, sizeof(*priv));
71 priv->key_idx = keyidx;
72 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))&&(!IN_OPENSUSE_SLED))
73 priv->tfm = crypto_alloc_tfm("arc4", 0);
74 if (priv->tfm == NULL) {
75 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
80 priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
81 if (IS_ERR(priv->tx_tfm)) {
82 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
87 priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
88 if (IS_ERR(priv->rx_tfm)) {
89 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
96 /* start WEP IV from a random value */
97 get_random_bytes(&priv->iv, 4);
102 //#if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))
103 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))&&(!IN_OPENSUSE_SLED))
106 crypto_free_tfm(priv->tfm);
112 crypto_free_blkcipher(priv->tx_tfm);
114 crypto_free_blkcipher(priv->rx_tfm);
122 static void prism2_wep_deinit(void *priv)
124 struct prism2_wep_data *_priv = priv;
125 //#if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))
126 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))&&(!IN_OPENSUSE_SLED))
127 if (_priv && _priv->tfm)
128 crypto_free_tfm(_priv->tfm);
132 crypto_free_blkcipher(_priv->tx_tfm);
134 crypto_free_blkcipher(_priv->rx_tfm);
141 /* Perform WEP encryption on given skb that has at least 4 bytes of headroom
142 * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
143 * so the payload length increases with 8 bytes.
145 * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
147 static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
149 struct prism2_wep_data *wep = priv;
150 //#if(LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21))
151 #if((LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21))||(IN_OPENSUSE_SLED))
152 struct blkcipher_desc desc = {.tfm = wep->tx_tfm};
155 u8 key[WEP_KEY_LEN + 3];
160 struct scatterlist sg;
162 if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
166 len = skb->len - hdr_len;
167 pos = skb_push(skb, 4);
168 memmove(pos, pos + 4, hdr_len);
171 klen = 3 + wep->key_len;
175 /* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
176 * scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
177 * can be used to speedup attacks, so avoid using them. */
178 if ((wep->iv & 0xff00) == 0xff00) {
179 u8 B = (wep->iv >> 16) & 0xff;
180 if (B >= 3 && B < klen)
184 /* Prepend 24-bit IV to RC4 key and TX frame */
185 *pos++ = key[0] = (wep->iv >> 16) & 0xff;
186 *pos++ = key[1] = (wep->iv >> 8) & 0xff;
187 *pos++ = key[2] = wep->iv & 0xff;
188 *pos++ = wep->key_idx << 6;
190 /* Copy rest of the WEP key (the secret part) */
191 memcpy(key + 3, wep->key, wep->key_len);
194 /* Append little-endian CRC32 and encrypt it to produce ICV */
195 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
196 crc = ~crc32_le(~0, pos, len);
198 crc = ~ether_crc_le(len, pos);
200 icv = skb_put(skb, 4);
206 //#if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))
207 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))&&(!IN_OPENSUSE_SLED))
208 crypto_cipher_setkey(wep->tfm, key, klen);
209 sg.page = virt_to_page(pos);
210 sg.offset = offset_in_page(pos);
212 crypto_cipher_encrypt(wep->tfm, &sg, &sg, len + 4);
216 crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
217 #if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24))
218 sg.page = virt_to_page(pos);
219 sg.offset = offset_in_page(pos);
222 sg_init_one(&sg, pos, len+4);
224 return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
226 #endif /* JOHN_HWSEC */
231 /* Perform WEP decryption on given buffer. Buffer includes whole WEP part of
232 * the frame: IV (4 bytes), encrypted payload (including SNAP header),
233 * ICV (4 bytes). len includes both IV and ICV.
235 * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
236 * failure. If frame is OK, IV and ICV will be removed.
238 static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
240 struct prism2_wep_data *wep = priv;
241 //#if(LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21))
242 #if((LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21))||(IN_OPENSUSE_SLED))
243 struct blkcipher_desc desc = {.tfm = wep->rx_tfm};
246 u8 key[WEP_KEY_LEN + 3];
251 struct scatterlist sg;
253 if (skb->len < hdr_len + 8)
256 pos = skb->data + hdr_len;
260 keyidx = *pos++ >> 6;
261 if (keyidx != wep->key_idx)
264 klen = 3 + wep->key_len;
266 /* Copy rest of the WEP key (the secret part) */
267 memcpy(key + 3, wep->key, wep->key_len);
269 /* Apply RC4 to data and compute CRC32 over decrypted data */
270 plen = skb->len - hdr_len - 8;
272 //#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))
273 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))&&(!IN_OPENSUSE_SLED))
274 crypto_cipher_setkey(wep->tfm, key, klen);
275 sg.page = virt_to_page(pos);
276 sg.offset = offset_in_page(pos);
277 sg.length = plen + 4;
278 crypto_cipher_decrypt(wep->tfm, &sg, &sg, plen + 4);
280 crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
281 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24))
282 sg.page = virt_to_page(pos);
283 sg.offset = offset_in_page(pos);
284 sg.length = plen + 4;
286 sg_init_one(&sg, pos, plen+4);
288 if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
292 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
293 crc = ~crc32_le(~0, pos, plen);
295 crc = ~ether_crc_le(plen, pos);
302 if (memcmp(icv, pos + plen, 4) != 0) {
303 /* ICV mismatch - drop frame */
306 #endif /* JOHN_HWSEC */
308 /* Remove IV and ICV */
309 memmove(skb->data + 4, skb->data, hdr_len);
311 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 ieee80211_crypto_wep_init(void)
371 return ieee80211_register_crypto_ops(&ieee80211_crypt_wep);
375 void ieee80211_crypto_wep_exit(void)
377 ieee80211_unregister_crypto_ops(&ieee80211_crypt_wep);
381 void ieee80211_wep_null(void)
383 // printk("============>%s()\n", __FUNCTION__);
387 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
388 EXPORT_SYMBOL(ieee80211_wep_null);
390 EXPORT_SYMBOL_NOVERS(ieee80211_wep_null);
393 //module_init(ieee80211_crypto_wep_init);
394 //module_exit(ieee80211_crypto_wep_exit);