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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>
20
21#include "ieee80211.h"
22
23#include <linux/crypto.h>
24#include <linux/scatterlist.h>
25#include <linux/crc32.h>
26
27MODULE_AUTHOR("Jouni Malinen");
28MODULE_DESCRIPTION("Host AP crypt: WEP");
29MODULE_LICENSE("GPL");
30
31struct prism2_wep_data {
32 u32 iv;
33#define WEP_KEY_LEN 13
34 u8 key[WEP_KEY_LEN + 1];
35 u8 key_len;
36 u8 key_idx;
37 struct crypto_blkcipher *tx_tfm;
38 struct crypto_blkcipher *rx_tfm;
39};
40
41
42static void * prism2_wep_init(int keyidx)
43{
44 struct prism2_wep_data *priv;
45
46 priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
47 if (priv == NULL)
48 goto fail;
49 memset(priv, 0, sizeof(*priv));
50 priv->key_idx = keyidx;
51
52 priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
53 if (IS_ERR(priv->tx_tfm)) {
54 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
55 "crypto API arc4\n");
56 priv->tx_tfm = NULL;
57 goto fail;
58 }
59 priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
60 if (IS_ERR(priv->rx_tfm)) {
61 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
62 "crypto API arc4\n");
63 priv->rx_tfm = NULL;
64 goto fail;
65 }
66
67
68 get_random_bytes(&priv->iv, 4);
69
70 return priv;
71
72fail:
73 if (priv) {
74 if (priv->tx_tfm)
75 crypto_free_blkcipher(priv->tx_tfm);
76 if (priv->rx_tfm)
77 crypto_free_blkcipher(priv->rx_tfm);
78 kfree(priv);
79 }
80
81 return NULL;
82}
83
84
85static void prism2_wep_deinit(void *priv)
86{
87 struct prism2_wep_data *_priv = priv;
88
89 if (_priv) {
90 if (_priv->tx_tfm)
91 crypto_free_blkcipher(_priv->tx_tfm);
92 if (_priv->rx_tfm)
93 crypto_free_blkcipher(_priv->rx_tfm);
94 }
95 kfree(priv);
96}
97
98
99
100
101
102
103
104static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
105{
106 struct prism2_wep_data *wep = priv;
107 u32 klen, len;
108 u8 key[WEP_KEY_LEN + 3];
109 u8 *pos;
110 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
111 struct blkcipher_desc desc = { .tfm = wep->tx_tfm };
112 u32 crc;
113 u8 *icv;
114 struct scatterlist sg;
115 if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
116 skb->len < hdr_len)
117 return -1;
118
119 len = skb->len - hdr_len;
120 pos = skb_push(skb, 4);
121 memmove(pos, pos + 4, hdr_len);
122 pos += hdr_len;
123
124 klen = 3 + wep->key_len;
125
126 wep->iv++;
127
128
129
130
131 if ((wep->iv & 0xff00) == 0xff00) {
132 u8 B = (wep->iv >> 16) & 0xff;
133 if (B >= 3 && B < klen)
134 wep->iv += 0x0100;
135 }
136
137
138 *pos++ = key[0] = (wep->iv >> 16) & 0xff;
139 *pos++ = key[1] = (wep->iv >> 8) & 0xff;
140 *pos++ = key[2] = wep->iv & 0xff;
141 *pos++ = wep->key_idx << 6;
142
143
144 memcpy(key + 3, wep->key, wep->key_len);
145
146 if (!tcb_desc->bHwSec)
147 {
148
149
150 crc = ~crc32_le(~0, pos, len);
151 icv = skb_put(skb, 4);
152 icv[0] = crc;
153 icv[1] = crc >> 8;
154 icv[2] = crc >> 16;
155 icv[3] = crc >> 24;
156
157 crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
158 sg_init_one(&sg, pos, len+4);
159
160 return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
161 }
162
163 return 0;
164}
165
166
167
168
169
170
171
172
173
174static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
175{
176 struct prism2_wep_data *wep = priv;
177 u32 klen, plen;
178 u8 key[WEP_KEY_LEN + 3];
179 u8 keyidx, *pos;
180 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
181 struct blkcipher_desc desc = { .tfm = wep->rx_tfm };
182 u32 crc;
183 u8 icv[4];
184 struct scatterlist sg;
185 if (skb->len < hdr_len + 8)
186 return -1;
187
188 pos = skb->data + hdr_len;
189 key[0] = *pos++;
190 key[1] = *pos++;
191 key[2] = *pos++;
192 keyidx = *pos++ >> 6;
193 if (keyidx != wep->key_idx)
194 return -1;
195
196 klen = 3 + wep->key_len;
197
198
199 memcpy(key + 3, wep->key, wep->key_len);
200
201
202 plen = skb->len - hdr_len - 8;
203
204 if (!tcb_desc->bHwSec)
205 {
206 crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
207 sg_init_one(&sg, pos, plen + 4);
208
209 if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
210 return -7;
211
212 crc = ~crc32_le(~0, pos, plen);
213 icv[0] = crc;
214 icv[1] = crc >> 8;
215 icv[2] = crc >> 16;
216 icv[3] = crc >> 24;
217 if (memcmp(icv, pos + plen, 4) != 0) {
218
219 return -2;
220 }
221 }
222
223 memmove(skb->data + 4, skb->data, hdr_len);
224 skb_pull(skb, 4);
225 skb_trim(skb, skb->len - 4);
226
227 return 0;
228}
229
230
231static int prism2_wep_set_key(void *key, int len, u8 *seq, void *priv)
232{
233 struct prism2_wep_data *wep = priv;
234
235 if (len < 0 || len > WEP_KEY_LEN)
236 return -1;
237
238 memcpy(wep->key, key, len);
239 wep->key_len = len;
240
241 return 0;
242}
243
244
245static int prism2_wep_get_key(void *key, int len, u8 *seq, void *priv)
246{
247 struct prism2_wep_data *wep = priv;
248
249 if (len < wep->key_len)
250 return -1;
251
252 memcpy(key, wep->key, wep->key_len);
253
254 return wep->key_len;
255}
256
257
258static char * prism2_wep_print_stats(char *p, void *priv)
259{
260 struct prism2_wep_data *wep = priv;
261 p += sprintf(p, "key[%d] alg=WEP len=%d\n",
262 wep->key_idx, wep->key_len);
263 return p;
264}
265
266
267static struct ieee80211_crypto_ops ieee80211_crypt_wep = {
268 .name = "WEP",
269 .init = prism2_wep_init,
270 .deinit = prism2_wep_deinit,
271 .encrypt_mpdu = prism2_wep_encrypt,
272 .decrypt_mpdu = prism2_wep_decrypt,
273 .encrypt_msdu = NULL,
274 .decrypt_msdu = NULL,
275 .set_key = prism2_wep_set_key,
276 .get_key = prism2_wep_get_key,
277 .print_stats = prism2_wep_print_stats,
278 .extra_prefix_len = 4,
279 .extra_postfix_len = 4,
280 .owner = THIS_MODULE,
281};
282
283int __init ieee80211_crypto_wep_init(void)
284{
285 return ieee80211_register_crypto_ops(&ieee80211_crypt_wep);
286}
287
288void __exit ieee80211_crypto_wep_exit(void)
289{
290 ieee80211_unregister_crypto_ops(&ieee80211_crypt_wep);
291}
292
293void ieee80211_wep_null(void)
294{
295
296 return;
297}
298