1
2
3
4
5
6
7
8
9
10
11
12
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/slab.h>
16#include <linux/random.h>
17#include <linux/skbuff.h>
18#include <asm/string.h>
19
20#include "ieee80211.h"
21
22#include <linux/crypto.h>
23 #include <linux/scatterlist.h>
24#include <linux/crc32.h>
25
26MODULE_AUTHOR("Jouni Malinen");
27MODULE_DESCRIPTION("Host AP crypt: WEP");
28MODULE_LICENSE("GPL");
29
30struct prism2_wep_data {
31 u32 iv;
32#define WEP_KEY_LEN 13
33 u8 key[WEP_KEY_LEN + 1];
34 u8 key_len;
35 u8 key_idx;
36 struct crypto_blkcipher *tx_tfm;
37 struct crypto_blkcipher *rx_tfm;
38};
39
40
41static void *prism2_wep_init(int keyidx)
42{
43 struct prism2_wep_data *priv;
44
45 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
46 if (priv == NULL)
47 goto fail;
48 priv->key_idx = keyidx;
49
50 priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
51 if (IS_ERR(priv->tx_tfm)) {
52 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
53 "crypto API arc4\n");
54 priv->tx_tfm = NULL;
55 goto fail;
56 }
57 priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
58 if (IS_ERR(priv->rx_tfm)) {
59 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
60 "crypto API arc4\n");
61 priv->rx_tfm = NULL;
62 goto fail;
63 }
64
65
66 get_random_bytes(&priv->iv, 4);
67
68 return priv;
69
70fail:
71 if (priv) {
72 if (priv->tx_tfm)
73 crypto_free_blkcipher(priv->tx_tfm);
74 if (priv->rx_tfm)
75 crypto_free_blkcipher(priv->rx_tfm);
76 kfree(priv);
77 }
78
79 return NULL;
80}
81
82
83static void prism2_wep_deinit(void *priv)
84{
85 struct prism2_wep_data *_priv = priv;
86
87 if (_priv) {
88 if (_priv->tx_tfm)
89 crypto_free_blkcipher(_priv->tx_tfm);
90 if (_priv->rx_tfm)
91 crypto_free_blkcipher(_priv->rx_tfm);
92 }
93 kfree(priv);
94}
95
96
97
98
99
100
101
102static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
103{
104 struct prism2_wep_data *wep = priv;
105 u32 klen, len;
106 u8 key[WEP_KEY_LEN + 3];
107 u8 *pos;
108 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
109 struct blkcipher_desc desc = {.tfm = wep->tx_tfm};
110 u32 crc;
111 u8 *icv;
112 struct scatterlist sg;
113 if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
114 skb->len < hdr_len)
115 return -1;
116
117 len = skb->len - hdr_len;
118 pos = skb_push(skb, 4);
119 memmove(pos, pos + 4, hdr_len);
120 pos += hdr_len;
121
122 klen = 3 + wep->key_len;
123
124 wep->iv++;
125
126
127
128
129 if ((wep->iv & 0xff00) == 0xff00) {
130 u8 B = (wep->iv >> 16) & 0xff;
131 if (B >= 3 && B < klen)
132 wep->iv += 0x0100;
133 }
134
135
136 *pos++ = key[0] = (wep->iv >> 16) & 0xff;
137 *pos++ = key[1] = (wep->iv >> 8) & 0xff;
138 *pos++ = key[2] = wep->iv & 0xff;
139 *pos++ = wep->key_idx << 6;
140
141
142 memcpy(key + 3, wep->key, wep->key_len);
143
144 if (!tcb_desc->bHwSec)
145 {
146
147
148 crc = ~crc32_le(~0, pos, len);
149 icv = skb_put(skb, 4);
150 icv[0] = crc;
151 icv[1] = crc >> 8;
152 icv[2] = crc >> 16;
153 icv[3] = crc >> 24;
154
155 crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
156 sg_init_one(&sg, pos, len+4);
157
158 return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
159 }
160
161 return 0;
162}
163
164
165
166
167
168
169
170
171
172static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
173{
174 struct prism2_wep_data *wep = priv;
175 u32 klen, plen;
176 u8 key[WEP_KEY_LEN + 3];
177 u8 keyidx, *pos;
178 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
179 struct blkcipher_desc desc = {.tfm = wep->rx_tfm};
180 u32 crc;
181 u8 icv[4];
182 struct scatterlist sg;
183 if (skb->len < hdr_len + 8)
184 return -1;
185
186 pos = skb->data + hdr_len;
187 key[0] = *pos++;
188 key[1] = *pos++;
189 key[2] = *pos++;
190 keyidx = *pos++ >> 6;
191 if (keyidx != wep->key_idx)
192 return -1;
193
194 klen = 3 + wep->key_len;
195
196
197 memcpy(key + 3, wep->key, wep->key_len);
198
199
200 plen = skb->len - hdr_len - 8;
201
202 if (!tcb_desc->bHwSec)
203 {
204 crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
205 sg_init_one(&sg, pos, plen+4);
206
207 if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
208 return -7;
209
210 crc = ~crc32_le(~0, pos, plen);
211 icv[0] = crc;
212 icv[1] = crc >> 8;
213 icv[2] = crc >> 16;
214 icv[3] = crc >> 24;
215 if (memcmp(icv, pos + plen, 4) != 0) {
216
217 return -2;
218 }
219 }
220
221 memmove(skb->data + 4, skb->data, hdr_len);
222 skb_pull(skb, 4);
223 skb_trim(skb, skb->len - 4);
224
225 return 0;
226}
227
228
229static int prism2_wep_set_key(void *key, int len, u8 *seq, void *priv)
230{
231 struct prism2_wep_data *wep = priv;
232
233 if (len < 0 || len > WEP_KEY_LEN)
234 return -1;
235
236 memcpy(wep->key, key, len);
237 wep->key_len = len;
238
239 return 0;
240}
241
242
243static int prism2_wep_get_key(void *key, int len, u8 *seq, void *priv)
244{
245 struct prism2_wep_data *wep = priv;
246
247 if (len < wep->key_len)
248 return -1;
249
250 memcpy(key, wep->key, wep->key_len);
251
252 return wep->key_len;
253}
254
255
256static char *prism2_wep_print_stats(char *p, void *priv)
257{
258 struct prism2_wep_data *wep = priv;
259 p += sprintf(p, "key[%d] alg=WEP len=%d\n",
260 wep->key_idx, wep->key_len);
261 return p;
262}
263
264
265static struct ieee80211_crypto_ops ieee80211_crypt_wep = {
266 .name = "WEP",
267 .init = prism2_wep_init,
268 .deinit = prism2_wep_deinit,
269 .encrypt_mpdu = prism2_wep_encrypt,
270 .decrypt_mpdu = prism2_wep_decrypt,
271 .encrypt_msdu = NULL,
272 .decrypt_msdu = NULL,
273 .set_key = prism2_wep_set_key,
274 .get_key = prism2_wep_get_key,
275 .print_stats = prism2_wep_print_stats,
276 .extra_prefix_len = 4,
277 .extra_postfix_len = 4,
278 .owner = THIS_MODULE,
279};
280
281int __init ieee80211_crypto_wep_init(void)
282{
283 return ieee80211_register_crypto_ops(&ieee80211_crypt_wep);
284}
285
286void __exit ieee80211_crypto_wep_exit(void)
287{
288 ieee80211_unregister_crypto_ops(&ieee80211_crypt_wep);
289}
290
291void ieee80211_wep_null(void)
292{
293
294 return;
295}
296