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11#include <linux/netdevice.h>
12#include <linux/types.h>
13#include <linux/random.h>
14#include <linux/compiler.h>
15#include <linux/crc32.h>
16#include <linux/crypto.h>
17#include <linux/err.h>
18#include <linux/mm.h>
19#include <linux/scatterlist.h>
20#include <asm/unaligned.h>
21
22#include <net/mac80211.h>
23#include "ieee80211_i.h"
24#include "wep.h"
25
26
27int ieee80211_wep_init(struct ieee80211_local *local)
28{
29
30 get_random_bytes(&local->wep_iv, WEP_IV_LEN);
31
32 local->wep_tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0,
33 CRYPTO_ALG_ASYNC);
34 if (IS_ERR(local->wep_tx_tfm))
35 return PTR_ERR(local->wep_tx_tfm);
36
37 local->wep_rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0,
38 CRYPTO_ALG_ASYNC);
39 if (IS_ERR(local->wep_rx_tfm)) {
40 crypto_free_blkcipher(local->wep_tx_tfm);
41 return PTR_ERR(local->wep_rx_tfm);
42 }
43
44 return 0;
45}
46
47void ieee80211_wep_free(struct ieee80211_local *local)
48{
49 crypto_free_blkcipher(local->wep_tx_tfm);
50 crypto_free_blkcipher(local->wep_rx_tfm);
51}
52
53static inline bool ieee80211_wep_weak_iv(u32 iv, int keylen)
54{
55
56
57
58
59
60 if ((iv & 0xff00) == 0xff00) {
61 u8 B = (iv >> 16) & 0xff;
62 if (B >= 3 && B < 3 + keylen)
63 return true;
64 }
65 return false;
66}
67
68
69static void ieee80211_wep_get_iv(struct ieee80211_local *local,
70 int keylen, int keyidx, u8 *iv)
71{
72 local->wep_iv++;
73 if (ieee80211_wep_weak_iv(local->wep_iv, keylen))
74 local->wep_iv += 0x0100;
75
76 if (!iv)
77 return;
78
79 *iv++ = (local->wep_iv >> 16) & 0xff;
80 *iv++ = (local->wep_iv >> 8) & 0xff;
81 *iv++ = local->wep_iv & 0xff;
82 *iv++ = keyidx << 6;
83}
84
85
86static u8 *ieee80211_wep_add_iv(struct ieee80211_local *local,
87 struct sk_buff *skb,
88 int keylen, int keyidx)
89{
90 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
91 unsigned int hdrlen;
92 u8 *newhdr;
93
94 hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
95
96 if (WARN_ON(skb_tailroom(skb) < WEP_ICV_LEN ||
97 skb_headroom(skb) < WEP_IV_LEN))
98 return NULL;
99
100 hdrlen = ieee80211_hdrlen(hdr->frame_control);
101 newhdr = skb_push(skb, WEP_IV_LEN);
102 memmove(newhdr, newhdr + WEP_IV_LEN, hdrlen);
103 ieee80211_wep_get_iv(local, keylen, keyidx, newhdr + hdrlen);
104 return newhdr + hdrlen;
105}
106
107
108static void ieee80211_wep_remove_iv(struct ieee80211_local *local,
109 struct sk_buff *skb,
110 struct ieee80211_key *key)
111{
112 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
113 unsigned int hdrlen;
114
115 hdrlen = ieee80211_hdrlen(hdr->frame_control);
116 memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen);
117 skb_pull(skb, WEP_IV_LEN);
118}
119
120
121
122
123
124void ieee80211_wep_encrypt_data(struct crypto_blkcipher *tfm, u8 *rc4key,
125 size_t klen, u8 *data, size_t data_len)
126{
127 struct blkcipher_desc desc = { .tfm = tfm };
128 struct scatterlist sg;
129 __le32 icv;
130
131 icv = cpu_to_le32(~crc32_le(~0, data, data_len));
132 put_unaligned(icv, (__le32 *)(data + data_len));
133
134 crypto_blkcipher_setkey(tfm, rc4key, klen);
135 sg_init_one(&sg, data, data_len + WEP_ICV_LEN);
136 crypto_blkcipher_encrypt(&desc, &sg, &sg, sg.length);
137}
138
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146
147int ieee80211_wep_encrypt(struct ieee80211_local *local,
148 struct sk_buff *skb,
149 const u8 *key, int keylen, int keyidx)
150{
151 u8 *iv;
152 size_t len;
153 u8 rc4key[3 + WLAN_KEY_LEN_WEP104];
154
155 iv = ieee80211_wep_add_iv(local, skb, keylen, keyidx);
156 if (!iv)
157 return -1;
158
159 len = skb->len - (iv + WEP_IV_LEN - skb->data);
160
161
162 memcpy(rc4key, iv, 3);
163
164
165 memcpy(rc4key + 3, key, keylen);
166
167
168 skb_put(skb, WEP_ICV_LEN);
169
170 ieee80211_wep_encrypt_data(local->wep_tx_tfm, rc4key, keylen + 3,
171 iv + WEP_IV_LEN, len);
172
173 return 0;
174}
175
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178
179
180int ieee80211_wep_decrypt_data(struct crypto_blkcipher *tfm, u8 *rc4key,
181 size_t klen, u8 *data, size_t data_len)
182{
183 struct blkcipher_desc desc = { .tfm = tfm };
184 struct scatterlist sg;
185 __le32 crc;
186
187 crypto_blkcipher_setkey(tfm, rc4key, klen);
188 sg_init_one(&sg, data, data_len + WEP_ICV_LEN);
189 crypto_blkcipher_decrypt(&desc, &sg, &sg, sg.length);
190
191 crc = cpu_to_le32(~crc32_le(~0, data, data_len));
192 if (memcmp(&crc, data + data_len, WEP_ICV_LEN) != 0)
193
194 return -1;
195
196 return 0;
197}
198
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206
207
208static int ieee80211_wep_decrypt(struct ieee80211_local *local,
209 struct sk_buff *skb,
210 struct ieee80211_key *key)
211{
212 u32 klen;
213 u8 *rc4key;
214 u8 keyidx;
215 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
216 unsigned int hdrlen;
217 size_t len;
218 int ret = 0;
219
220 if (!ieee80211_has_protected(hdr->frame_control))
221 return -1;
222
223 hdrlen = ieee80211_hdrlen(hdr->frame_control);
224 if (skb->len < hdrlen + WEP_IV_LEN + WEP_ICV_LEN)
225 return -1;
226
227 len = skb->len - hdrlen - WEP_IV_LEN - WEP_ICV_LEN;
228
229 keyidx = skb->data[hdrlen + 3] >> 6;
230
231 if (!key || keyidx != key->conf.keyidx || key->conf.alg != ALG_WEP)
232 return -1;
233
234 klen = 3 + key->conf.keylen;
235
236 rc4key = kmalloc(klen, GFP_ATOMIC);
237 if (!rc4key)
238 return -1;
239
240
241 memcpy(rc4key, skb->data + hdrlen, 3);
242
243
244 memcpy(rc4key + 3, key->conf.key, key->conf.keylen);
245
246 if (ieee80211_wep_decrypt_data(local->wep_rx_tfm, rc4key, klen,
247 skb->data + hdrlen + WEP_IV_LEN,
248 len))
249 ret = -1;
250
251 kfree(rc4key);
252
253
254 skb_trim(skb, skb->len - WEP_ICV_LEN);
255
256
257 memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen);
258 skb_pull(skb, WEP_IV_LEN);
259
260 return ret;
261}
262
263
264bool ieee80211_wep_is_weak_iv(struct sk_buff *skb, struct ieee80211_key *key)
265{
266 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
267 unsigned int hdrlen;
268 u8 *ivpos;
269 u32 iv;
270
271 if (!ieee80211_has_protected(hdr->frame_control))
272 return false;
273
274 hdrlen = ieee80211_hdrlen(hdr->frame_control);
275 ivpos = skb->data + hdrlen;
276 iv = (ivpos[0] << 16) | (ivpos[1] << 8) | ivpos[2];
277
278 return ieee80211_wep_weak_iv(iv, key->conf.keylen);
279}
280
281ieee80211_rx_result
282ieee80211_crypto_wep_decrypt(struct ieee80211_rx_data *rx)
283{
284 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
285
286 if (!ieee80211_is_data(hdr->frame_control) &&
287 !ieee80211_is_auth(hdr->frame_control))
288 return RX_CONTINUE;
289
290 if (!(rx->status->flag & RX_FLAG_DECRYPTED)) {
291 if (ieee80211_wep_decrypt(rx->local, rx->skb, rx->key))
292 return RX_DROP_UNUSABLE;
293 } else if (!(rx->status->flag & RX_FLAG_IV_STRIPPED)) {
294 ieee80211_wep_remove_iv(rx->local, rx->skb, rx->key);
295
296 skb_trim(rx->skb, rx->skb->len - WEP_ICV_LEN);
297 }
298
299 return RX_CONTINUE;
300}
301
302static int wep_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
303{
304 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
305
306 if (!(tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)) {
307 if (ieee80211_wep_encrypt(tx->local, skb, tx->key->conf.key,
308 tx->key->conf.keylen,
309 tx->key->conf.keyidx))
310 return -1;
311 } else {
312 info->control.hw_key = &tx->key->conf;
313 if (tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) {
314 if (!ieee80211_wep_add_iv(tx->local, skb,
315 tx->key->conf.keylen,
316 tx->key->conf.keyidx))
317 return -1;
318 }
319 }
320 return 0;
321}
322
323ieee80211_tx_result
324ieee80211_crypto_wep_encrypt(struct ieee80211_tx_data *tx)
325{
326 struct sk_buff *skb;
327
328 ieee80211_tx_set_protected(tx);
329
330 skb = tx->skb;
331 do {
332 if (wep_encrypt_skb(tx, skb) < 0) {
333 I802_DEBUG_INC(tx->local->tx_handlers_drop_wep);
334 return TX_DROP;
335 }
336 } while ((skb = skb->next));
337
338 return TX_CONTINUE;
339}
340