Commit | Line | Data |
---|---|---|
f0706e82 JB |
1 | /* |
2 | * Software WEP encryption implementation | |
3 | * Copyright 2002, Jouni Malinen <jkmaline@cc.hut.fi> | |
4 | * Copyright 2003, Instant802 Networks, Inc. | |
5 | * | |
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. | |
9 | */ | |
10 | ||
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> | |
11763609 | 19 | #include <linux/scatterlist.h> |
5a0e3ad6 | 20 | #include <linux/slab.h> |
860c6e6a | 21 | #include <asm/unaligned.h> |
f0706e82 JB |
22 | |
23 | #include <net/mac80211.h> | |
24 | #include "ieee80211_i.h" | |
25 | #include "wep.h" | |
26 | ||
27 | ||
28 | int ieee80211_wep_init(struct ieee80211_local *local) | |
29 | { | |
30 | /* start WEP IV from a random value */ | |
31 | get_random_bytes(&local->wep_iv, WEP_IV_LEN); | |
32 | ||
5f9f1812 | 33 | local->wep_tx_tfm = crypto_alloc_cipher("arc4", 0, CRYPTO_ALG_ASYNC); |
088c8726 JL |
34 | if (IS_ERR(local->wep_tx_tfm)) { |
35 | local->wep_rx_tfm = ERR_PTR(-EINVAL); | |
023a04be | 36 | return PTR_ERR(local->wep_tx_tfm); |
088c8726 | 37 | } |
f0706e82 | 38 | |
5f9f1812 | 39 | local->wep_rx_tfm = crypto_alloc_cipher("arc4", 0, CRYPTO_ALG_ASYNC); |
f0706e82 | 40 | if (IS_ERR(local->wep_rx_tfm)) { |
5f9f1812 | 41 | crypto_free_cipher(local->wep_tx_tfm); |
088c8726 | 42 | local->wep_tx_tfm = ERR_PTR(-EINVAL); |
023a04be | 43 | return PTR_ERR(local->wep_rx_tfm); |
f0706e82 JB |
44 | } |
45 | ||
46 | return 0; | |
47 | } | |
48 | ||
49 | void ieee80211_wep_free(struct ieee80211_local *local) | |
50 | { | |
3473187d | 51 | if (!IS_ERR(local->wep_tx_tfm)) |
5f9f1812 | 52 | crypto_free_cipher(local->wep_tx_tfm); |
3473187d | 53 | if (!IS_ERR(local->wep_rx_tfm)) |
5f9f1812 | 54 | crypto_free_cipher(local->wep_rx_tfm); |
f0706e82 JB |
55 | } |
56 | ||
c6a1fa12 | 57 | static inline bool ieee80211_wep_weak_iv(u32 iv, int keylen) |
f0706e82 | 58 | { |
c6a1fa12 JB |
59 | /* |
60 | * Fluhrer, Mantin, and Shamir have reported weaknesses in the | |
f0706e82 | 61 | * key scheduling algorithm of RC4. At least IVs (KeyByte + 3, |
c6a1fa12 JB |
62 | * 0xff, N) can be used to speedup attacks, so avoid using them. |
63 | */ | |
f0706e82 JB |
64 | if ((iv & 0xff00) == 0xff00) { |
65 | u8 B = (iv >> 16) & 0xff; | |
66 | if (B >= 3 && B < 3 + keylen) | |
c6a1fa12 | 67 | return true; |
f0706e82 | 68 | } |
c6a1fa12 | 69 | return false; |
f0706e82 JB |
70 | } |
71 | ||
72 | ||
4f0d18e2 | 73 | static void ieee80211_wep_get_iv(struct ieee80211_local *local, |
c9cf0122 | 74 | int keylen, int keyidx, u8 *iv) |
f0706e82 JB |
75 | { |
76 | local->wep_iv++; | |
c9cf0122 | 77 | if (ieee80211_wep_weak_iv(local->wep_iv, keylen)) |
f0706e82 JB |
78 | local->wep_iv += 0x0100; |
79 | ||
80 | if (!iv) | |
81 | return; | |
82 | ||
83 | *iv++ = (local->wep_iv >> 16) & 0xff; | |
84 | *iv++ = (local->wep_iv >> 8) & 0xff; | |
85 | *iv++ = local->wep_iv & 0xff; | |
c9cf0122 | 86 | *iv++ = keyidx << 6; |
f0706e82 JB |
87 | } |
88 | ||
89 | ||
6a22a59d JB |
90 | static u8 *ieee80211_wep_add_iv(struct ieee80211_local *local, |
91 | struct sk_buff *skb, | |
c9cf0122 | 92 | int keylen, int keyidx) |
f0706e82 | 93 | { |
70217d7f | 94 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; |
ee70108f | 95 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); |
70217d7f | 96 | unsigned int hdrlen; |
f0706e82 JB |
97 | u8 *newhdr; |
98 | ||
70217d7f | 99 | hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED); |
f0706e82 | 100 | |
23c0752a JB |
101 | if (WARN_ON(skb_tailroom(skb) < WEP_ICV_LEN || |
102 | skb_headroom(skb) < WEP_IV_LEN)) | |
103 | return NULL; | |
f0706e82 | 104 | |
70217d7f | 105 | hdrlen = ieee80211_hdrlen(hdr->frame_control); |
f0706e82 JB |
106 | newhdr = skb_push(skb, WEP_IV_LEN); |
107 | memmove(newhdr, newhdr + WEP_IV_LEN, hdrlen); | |
ee70108f JD |
108 | |
109 | /* the HW only needs room for the IV, but not the actual IV */ | |
110 | if (info->control.hw_key && | |
111 | (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) | |
112 | return newhdr + hdrlen; | |
113 | ||
7863157d | 114 | skb_set_network_header(skb, skb_network_offset(skb) + WEP_IV_LEN); |
c9cf0122 | 115 | ieee80211_wep_get_iv(local, keylen, keyidx, newhdr + hdrlen); |
f0706e82 JB |
116 | return newhdr + hdrlen; |
117 | } | |
118 | ||
119 | ||
4f0d18e2 JB |
120 | static void ieee80211_wep_remove_iv(struct ieee80211_local *local, |
121 | struct sk_buff *skb, | |
122 | struct ieee80211_key *key) | |
f0706e82 | 123 | { |
70217d7f HH |
124 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; |
125 | unsigned int hdrlen; | |
f0706e82 | 126 | |
70217d7f | 127 | hdrlen = ieee80211_hdrlen(hdr->frame_control); |
f0706e82 JB |
128 | memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen); |
129 | skb_pull(skb, WEP_IV_LEN); | |
130 | } | |
131 | ||
132 | ||
133 | /* Perform WEP encryption using given key. data buffer must have tailroom | |
134 | * for 4-byte ICV. data_len must not include this ICV. Note: this function | |
135 | * does _not_ add IV. data = RC4(data | CRC32(data)) */ | |
5f9f1812 | 136 | int ieee80211_wep_encrypt_data(struct crypto_cipher *tfm, u8 *rc4key, |
3473187d | 137 | size_t klen, u8 *data, size_t data_len) |
f0706e82 | 138 | { |
860c6e6a | 139 | __le32 icv; |
5f9f1812 | 140 | int i; |
f0706e82 | 141 | |
3473187d JL |
142 | if (IS_ERR(tfm)) |
143 | return -1; | |
144 | ||
860c6e6a IK |
145 | icv = cpu_to_le32(~crc32_le(~0, data, data_len)); |
146 | put_unaligned(icv, (__le32 *)(data + data_len)); | |
f0706e82 | 147 | |
5f9f1812 FF |
148 | crypto_cipher_setkey(tfm, rc4key, klen); |
149 | for (i = 0; i < data_len + WEP_ICV_LEN; i++) | |
150 | crypto_cipher_encrypt_one(tfm, data + i, data + i); | |
3473187d JL |
151 | |
152 | return 0; | |
f0706e82 JB |
153 | } |
154 | ||
155 | ||
156 | /* Perform WEP encryption on given skb. 4 bytes of extra space (IV) in the | |
157 | * beginning of the buffer 4 bytes of extra space (ICV) in the end of the | |
158 | * buffer will be added. Both IV and ICV will be transmitted, so the | |
159 | * payload length increases with 8 bytes. | |
160 | * | |
161 | * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data)) | |
162 | */ | |
fffd0934 JB |
163 | int ieee80211_wep_encrypt(struct ieee80211_local *local, |
164 | struct sk_buff *skb, | |
165 | const u8 *key, int keylen, int keyidx) | |
f0706e82 | 166 | { |
c9cf0122 | 167 | u8 *iv; |
f0706e82 | 168 | size_t len; |
c9cf0122 | 169 | u8 rc4key[3 + WLAN_KEY_LEN_WEP104]; |
f0706e82 | 170 | |
c9cf0122 JB |
171 | iv = ieee80211_wep_add_iv(local, skb, keylen, keyidx); |
172 | if (!iv) | |
f0706e82 | 173 | return -1; |
f0706e82 JB |
174 | |
175 | len = skb->len - (iv + WEP_IV_LEN - skb->data); | |
176 | ||
177 | /* Prepend 24-bit IV to RC4 key */ | |
178 | memcpy(rc4key, iv, 3); | |
179 | ||
180 | /* Copy rest of the WEP key (the secret part) */ | |
c9cf0122 | 181 | memcpy(rc4key + 3, key, keylen); |
f0706e82 JB |
182 | |
183 | /* Add room for ICV */ | |
184 | skb_put(skb, WEP_ICV_LEN); | |
185 | ||
3473187d JL |
186 | return ieee80211_wep_encrypt_data(local->wep_tx_tfm, rc4key, keylen + 3, |
187 | iv + WEP_IV_LEN, len); | |
f0706e82 JB |
188 | } |
189 | ||
190 | ||
191 | /* Perform WEP decryption using given key. data buffer includes encrypted | |
192 | * payload, including 4-byte ICV, but _not_ IV. data_len must not include ICV. | |
193 | * Return 0 on success and -1 on ICV mismatch. */ | |
5f9f1812 | 194 | int ieee80211_wep_decrypt_data(struct crypto_cipher *tfm, u8 *rc4key, |
f0706e82 JB |
195 | size_t klen, u8 *data, size_t data_len) |
196 | { | |
f0706e82 | 197 | __le32 crc; |
5f9f1812 | 198 | int i; |
f0706e82 | 199 | |
3473187d JL |
200 | if (IS_ERR(tfm)) |
201 | return -1; | |
202 | ||
5f9f1812 FF |
203 | crypto_cipher_setkey(tfm, rc4key, klen); |
204 | for (i = 0; i < data_len + WEP_ICV_LEN; i++) | |
205 | crypto_cipher_decrypt_one(tfm, data + i, data + i); | |
f0706e82 JB |
206 | |
207 | crc = cpu_to_le32(~crc32_le(~0, data, data_len)); | |
208 | if (memcmp(&crc, data + data_len, WEP_ICV_LEN) != 0) | |
209 | /* ICV mismatch */ | |
210 | return -1; | |
211 | ||
212 | return 0; | |
213 | } | |
214 | ||
215 | ||
216 | /* Perform WEP decryption on given skb. Buffer includes whole WEP part of | |
217 | * the frame: IV (4 bytes), encrypted payload (including SNAP header), | |
218 | * ICV (4 bytes). skb->len includes both IV and ICV. | |
219 | * | |
220 | * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on | |
221 | * failure. If frame is OK, IV and ICV will be removed, i.e., decrypted payload | |
222 | * is moved to the beginning of the skb and skb length will be reduced. | |
223 | */ | |
c9cf0122 JB |
224 | static int ieee80211_wep_decrypt(struct ieee80211_local *local, |
225 | struct sk_buff *skb, | |
226 | struct ieee80211_key *key) | |
f0706e82 JB |
227 | { |
228 | u32 klen; | |
730bd83b | 229 | u8 rc4key[3 + WLAN_KEY_LEN_WEP104]; |
f0706e82 | 230 | u8 keyidx; |
70217d7f HH |
231 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; |
232 | unsigned int hdrlen; | |
f0706e82 JB |
233 | size_t len; |
234 | int ret = 0; | |
235 | ||
70217d7f | 236 | if (!ieee80211_has_protected(hdr->frame_control)) |
f0706e82 JB |
237 | return -1; |
238 | ||
70217d7f | 239 | hdrlen = ieee80211_hdrlen(hdr->frame_control); |
d2984872 | 240 | if (skb->len < hdrlen + WEP_IV_LEN + WEP_ICV_LEN) |
f0706e82 JB |
241 | return -1; |
242 | ||
d2984872 | 243 | len = skb->len - hdrlen - WEP_IV_LEN - WEP_ICV_LEN; |
f0706e82 JB |
244 | |
245 | keyidx = skb->data[hdrlen + 3] >> 6; | |
246 | ||
97359d12 | 247 | if (!key || keyidx != key->conf.keyidx) |
f0706e82 JB |
248 | return -1; |
249 | ||
8f20fc24 | 250 | klen = 3 + key->conf.keylen; |
f0706e82 | 251 | |
f0706e82 JB |
252 | /* Prepend 24-bit IV to RC4 key */ |
253 | memcpy(rc4key, skb->data + hdrlen, 3); | |
254 | ||
255 | /* Copy rest of the WEP key (the secret part) */ | |
8f20fc24 | 256 | memcpy(rc4key + 3, key->conf.key, key->conf.keylen); |
f0706e82 JB |
257 | |
258 | if (ieee80211_wep_decrypt_data(local->wep_rx_tfm, rc4key, klen, | |
259 | skb->data + hdrlen + WEP_IV_LEN, | |
f4ea83dd | 260 | len)) |
f0706e82 | 261 | ret = -1; |
f0706e82 | 262 | |
f0706e82 JB |
263 | /* Trim ICV */ |
264 | skb_trim(skb, skb->len - WEP_ICV_LEN); | |
265 | ||
266 | /* Remove IV */ | |
267 | memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen); | |
268 | skb_pull(skb, WEP_IV_LEN); | |
269 | ||
270 | return ret; | |
271 | } | |
272 | ||
273 | ||
617bbde8 JB |
274 | static bool ieee80211_wep_is_weak_iv(struct sk_buff *skb, |
275 | struct ieee80211_key *key) | |
f0706e82 | 276 | { |
70217d7f HH |
277 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; |
278 | unsigned int hdrlen; | |
f0706e82 JB |
279 | u8 *ivpos; |
280 | u32 iv; | |
281 | ||
70217d7f | 282 | hdrlen = ieee80211_hdrlen(hdr->frame_control); |
f0706e82 JB |
283 | ivpos = skb->data + hdrlen; |
284 | iv = (ivpos[0] << 16) | (ivpos[1] << 8) | ivpos[2]; | |
285 | ||
c6a1fa12 | 286 | return ieee80211_wep_weak_iv(iv, key->conf.keylen); |
f0706e82 | 287 | } |
4f0d18e2 | 288 | |
9ae54c84 | 289 | ieee80211_rx_result |
5cf121c3 | 290 | ieee80211_crypto_wep_decrypt(struct ieee80211_rx_data *rx) |
4f0d18e2 | 291 | { |
eb9fb5b8 JB |
292 | struct sk_buff *skb = rx->skb; |
293 | struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); | |
294 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; | |
a8286911 | 295 | __le16 fc = hdr->frame_control; |
358c8d9d | 296 | |
a8286911 | 297 | if (!ieee80211_is_data(fc) && !ieee80211_is_auth(fc)) |
9ae54c84 | 298 | return RX_CONTINUE; |
4f0d18e2 | 299 | |
eb9fb5b8 | 300 | if (!(status->flag & RX_FLAG_DECRYPTED)) { |
a8286911 JB |
301 | if (skb_linearize(rx->skb)) |
302 | return RX_DROP_UNUSABLE; | |
617bbde8 JB |
303 | if (rx->sta && ieee80211_wep_is_weak_iv(rx->skb, rx->key)) |
304 | rx->sta->wep_weak_iv_count++; | |
f4ea83dd | 305 | if (ieee80211_wep_decrypt(rx->local, rx->skb, rx->key)) |
e4c26add | 306 | return RX_DROP_UNUSABLE; |
eb9fb5b8 | 307 | } else if (!(status->flag & RX_FLAG_IV_STRIPPED)) { |
a8286911 JB |
308 | if (!pskb_may_pull(rx->skb, ieee80211_hdrlen(fc) + WEP_IV_LEN)) |
309 | return RX_DROP_UNUSABLE; | |
617bbde8 JB |
310 | if (rx->sta && ieee80211_wep_is_weak_iv(rx->skb, rx->key)) |
311 | rx->sta->wep_weak_iv_count++; | |
4f0d18e2 JB |
312 | ieee80211_wep_remove_iv(rx->local, rx->skb, rx->key); |
313 | /* remove ICV */ | |
a8286911 JB |
314 | if (pskb_trim(rx->skb, rx->skb->len - WEP_ICV_LEN)) |
315 | return RX_DROP_UNUSABLE; | |
4f0d18e2 JB |
316 | } |
317 | ||
9ae54c84 | 318 | return RX_CONTINUE; |
4f0d18e2 | 319 | } |
6a22a59d | 320 | |
5cf121c3 | 321 | static int wep_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) |
6a22a59d | 322 | { |
e039fa4a | 323 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); |
ee70108f | 324 | struct ieee80211_key_conf *hw_key = info->control.hw_key; |
e039fa4a | 325 | |
ee70108f | 326 | if (!hw_key) { |
c9cf0122 JB |
327 | if (ieee80211_wep_encrypt(tx->local, skb, tx->key->conf.key, |
328 | tx->key->conf.keylen, | |
329 | tx->key->conf.keyidx)) | |
6a22a59d | 330 | return -1; |
ee70108f JD |
331 | } else if ((hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) || |
332 | (hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { | |
813d7669 JB |
333 | if (!ieee80211_wep_add_iv(tx->local, skb, |
334 | tx->key->conf.keylen, | |
335 | tx->key->conf.keyidx)) | |
336 | return -1; | |
337 | } | |
338 | ||
6a22a59d JB |
339 | return 0; |
340 | } | |
341 | ||
9ae54c84 | 342 | ieee80211_tx_result |
5cf121c3 | 343 | ieee80211_crypto_wep_encrypt(struct ieee80211_tx_data *tx) |
6a22a59d | 344 | { |
2de8e0d9 | 345 | struct sk_buff *skb; |
c6a1fa12 | 346 | |
5cf121c3 | 347 | ieee80211_tx_set_protected(tx); |
6a22a59d | 348 | |
252b86c4 | 349 | skb_queue_walk(&tx->skbs, skb) { |
2de8e0d9 JB |
350 | if (wep_encrypt_skb(tx, skb) < 0) { |
351 | I802_DEBUG_INC(tx->local->tx_handlers_drop_wep); | |
352 | return TX_DROP; | |
6a22a59d | 353 | } |
252b86c4 | 354 | } |
6a22a59d | 355 | |
9ae54c84 | 356 | return TX_CONTINUE; |
6a22a59d | 357 | } |