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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
f0706e82 JB |
2 | /* |
3 | * Software WEP encryption implementation | |
4 | * Copyright 2002, Jouni Malinen <jkmaline@cc.hut.fi> | |
5 | * Copyright 2003, Instant802 Networks, Inc. | |
f0706e82 JB |
6 | */ |
7 | ||
8 | #include <linux/netdevice.h> | |
9 | #include <linux/types.h> | |
10 | #include <linux/random.h> | |
11 | #include <linux/compiler.h> | |
12 | #include <linux/crc32.h> | |
13 | #include <linux/crypto.h> | |
14 | #include <linux/err.h> | |
15 | #include <linux/mm.h> | |
11763609 | 16 | #include <linux/scatterlist.h> |
5a0e3ad6 | 17 | #include <linux/slab.h> |
860c6e6a | 18 | #include <asm/unaligned.h> |
f0706e82 JB |
19 | |
20 | #include <net/mac80211.h> | |
21 | #include "ieee80211_i.h" | |
22 | #include "wep.h" | |
23 | ||
24 | ||
25 | int ieee80211_wep_init(struct ieee80211_local *local) | |
26 | { | |
27 | /* start WEP IV from a random value */ | |
4325f6ca | 28 | get_random_bytes(&local->wep_iv, IEEE80211_WEP_IV_LEN); |
f0706e82 | 29 | |
f0706e82 JB |
30 | return 0; |
31 | } | |
32 | ||
c6a1fa12 | 33 | static inline bool ieee80211_wep_weak_iv(u32 iv, int keylen) |
f0706e82 | 34 | { |
c6a1fa12 JB |
35 | /* |
36 | * Fluhrer, Mantin, and Shamir have reported weaknesses in the | |
f0706e82 | 37 | * key scheduling algorithm of RC4. At least IVs (KeyByte + 3, |
c6a1fa12 JB |
38 | * 0xff, N) can be used to speedup attacks, so avoid using them. |
39 | */ | |
f0706e82 JB |
40 | if ((iv & 0xff00) == 0xff00) { |
41 | u8 B = (iv >> 16) & 0xff; | |
42 | if (B >= 3 && B < 3 + keylen) | |
c6a1fa12 | 43 | return true; |
f0706e82 | 44 | } |
c6a1fa12 | 45 | return false; |
f0706e82 JB |
46 | } |
47 | ||
48 | ||
4f0d18e2 | 49 | static void ieee80211_wep_get_iv(struct ieee80211_local *local, |
c9cf0122 | 50 | int keylen, int keyidx, u8 *iv) |
f0706e82 JB |
51 | { |
52 | local->wep_iv++; | |
c9cf0122 | 53 | if (ieee80211_wep_weak_iv(local->wep_iv, keylen)) |
f0706e82 JB |
54 | local->wep_iv += 0x0100; |
55 | ||
56 | if (!iv) | |
57 | return; | |
58 | ||
59 | *iv++ = (local->wep_iv >> 16) & 0xff; | |
60 | *iv++ = (local->wep_iv >> 8) & 0xff; | |
61 | *iv++ = local->wep_iv & 0xff; | |
c9cf0122 | 62 | *iv++ = keyidx << 6; |
f0706e82 JB |
63 | } |
64 | ||
65 | ||
6a22a59d JB |
66 | static u8 *ieee80211_wep_add_iv(struct ieee80211_local *local, |
67 | struct sk_buff *skb, | |
c9cf0122 | 68 | int keylen, int keyidx) |
f0706e82 | 69 | { |
70217d7f | 70 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; |
ee70108f | 71 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); |
70217d7f | 72 | unsigned int hdrlen; |
f0706e82 JB |
73 | u8 *newhdr; |
74 | ||
70217d7f | 75 | hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED); |
f0706e82 | 76 | |
47b4e1fc | 77 | if (WARN_ON(skb_headroom(skb) < IEEE80211_WEP_IV_LEN)) |
23c0752a | 78 | return NULL; |
f0706e82 | 79 | |
70217d7f | 80 | hdrlen = ieee80211_hdrlen(hdr->frame_control); |
4325f6ca JB |
81 | newhdr = skb_push(skb, IEEE80211_WEP_IV_LEN); |
82 | memmove(newhdr, newhdr + IEEE80211_WEP_IV_LEN, hdrlen); | |
ee70108f JD |
83 | |
84 | /* the HW only needs room for the IV, but not the actual IV */ | |
85 | if (info->control.hw_key && | |
86 | (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) | |
87 | return newhdr + hdrlen; | |
88 | ||
c9cf0122 | 89 | ieee80211_wep_get_iv(local, keylen, keyidx, newhdr + hdrlen); |
f0706e82 JB |
90 | return newhdr + hdrlen; |
91 | } | |
92 | ||
93 | ||
4f0d18e2 JB |
94 | static void ieee80211_wep_remove_iv(struct ieee80211_local *local, |
95 | struct sk_buff *skb, | |
96 | struct ieee80211_key *key) | |
f0706e82 | 97 | { |
70217d7f HH |
98 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; |
99 | unsigned int hdrlen; | |
f0706e82 | 100 | |
70217d7f | 101 | hdrlen = ieee80211_hdrlen(hdr->frame_control); |
4325f6ca JB |
102 | memmove(skb->data + IEEE80211_WEP_IV_LEN, skb->data, hdrlen); |
103 | skb_pull(skb, IEEE80211_WEP_IV_LEN); | |
f0706e82 JB |
104 | } |
105 | ||
106 | ||
107 | /* Perform WEP encryption using given key. data buffer must have tailroom | |
108 | * for 4-byte ICV. data_len must not include this ICV. Note: this function | |
109 | * does _not_ add IV. data = RC4(data | CRC32(data)) */ | |
5fdb3735 | 110 | int ieee80211_wep_encrypt_data(struct arc4_ctx *ctx, u8 *rc4key, |
3473187d | 111 | size_t klen, u8 *data, size_t data_len) |
f0706e82 | 112 | { |
860c6e6a | 113 | __le32 icv; |
3473187d | 114 | |
860c6e6a IK |
115 | icv = cpu_to_le32(~crc32_le(~0, data, data_len)); |
116 | put_unaligned(icv, (__le32 *)(data + data_len)); | |
f0706e82 | 117 | |
5fdb3735 AB |
118 | arc4_setkey(ctx, rc4key, klen); |
119 | arc4_crypt(ctx, data, data, data_len + IEEE80211_WEP_ICV_LEN); | |
120 | memzero_explicit(ctx, sizeof(*ctx)); | |
3473187d JL |
121 | |
122 | return 0; | |
f0706e82 JB |
123 | } |
124 | ||
125 | ||
126 | /* Perform WEP encryption on given skb. 4 bytes of extra space (IV) in the | |
127 | * beginning of the buffer 4 bytes of extra space (ICV) in the end of the | |
128 | * buffer will be added. Both IV and ICV will be transmitted, so the | |
129 | * payload length increases with 8 bytes. | |
130 | * | |
131 | * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data)) | |
132 | */ | |
fffd0934 JB |
133 | int ieee80211_wep_encrypt(struct ieee80211_local *local, |
134 | struct sk_buff *skb, | |
135 | const u8 *key, int keylen, int keyidx) | |
f0706e82 | 136 | { |
c9cf0122 | 137 | u8 *iv; |
f0706e82 | 138 | size_t len; |
c9cf0122 | 139 | u8 rc4key[3 + WLAN_KEY_LEN_WEP104]; |
f0706e82 | 140 | |
47b4e1fc JD |
141 | if (WARN_ON(skb_tailroom(skb) < IEEE80211_WEP_ICV_LEN)) |
142 | return -1; | |
143 | ||
c9cf0122 JB |
144 | iv = ieee80211_wep_add_iv(local, skb, keylen, keyidx); |
145 | if (!iv) | |
f0706e82 | 146 | return -1; |
f0706e82 | 147 | |
4325f6ca | 148 | len = skb->len - (iv + IEEE80211_WEP_IV_LEN - skb->data); |
f0706e82 JB |
149 | |
150 | /* Prepend 24-bit IV to RC4 key */ | |
151 | memcpy(rc4key, iv, 3); | |
152 | ||
153 | /* Copy rest of the WEP key (the secret part) */ | |
c9cf0122 | 154 | memcpy(rc4key + 3, key, keylen); |
f0706e82 JB |
155 | |
156 | /* Add room for ICV */ | |
4325f6ca | 157 | skb_put(skb, IEEE80211_WEP_ICV_LEN); |
f0706e82 | 158 | |
5fdb3735 | 159 | return ieee80211_wep_encrypt_data(&local->wep_tx_ctx, rc4key, keylen + 3, |
4325f6ca | 160 | iv + IEEE80211_WEP_IV_LEN, len); |
f0706e82 JB |
161 | } |
162 | ||
163 | ||
164 | /* Perform WEP decryption using given key. data buffer includes encrypted | |
165 | * payload, including 4-byte ICV, but _not_ IV. data_len must not include ICV. | |
166 | * Return 0 on success and -1 on ICV mismatch. */ | |
5fdb3735 | 167 | int ieee80211_wep_decrypt_data(struct arc4_ctx *ctx, u8 *rc4key, |
f0706e82 JB |
168 | size_t klen, u8 *data, size_t data_len) |
169 | { | |
f0706e82 | 170 | __le32 crc; |
3473187d | 171 | |
5fdb3735 AB |
172 | arc4_setkey(ctx, rc4key, klen); |
173 | arc4_crypt(ctx, data, data, data_len + IEEE80211_WEP_ICV_LEN); | |
174 | memzero_explicit(ctx, sizeof(*ctx)); | |
f0706e82 JB |
175 | |
176 | crc = cpu_to_le32(~crc32_le(~0, data, data_len)); | |
4325f6ca | 177 | if (memcmp(&crc, data + data_len, IEEE80211_WEP_ICV_LEN) != 0) |
f0706e82 JB |
178 | /* ICV mismatch */ |
179 | return -1; | |
180 | ||
181 | return 0; | |
182 | } | |
183 | ||
184 | ||
185 | /* Perform WEP decryption on given skb. Buffer includes whole WEP part of | |
186 | * the frame: IV (4 bytes), encrypted payload (including SNAP header), | |
187 | * ICV (4 bytes). skb->len includes both IV and ICV. | |
188 | * | |
189 | * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on | |
190 | * failure. If frame is OK, IV and ICV will be removed, i.e., decrypted payload | |
191 | * is moved to the beginning of the skb and skb length will be reduced. | |
192 | */ | |
c9cf0122 JB |
193 | static int ieee80211_wep_decrypt(struct ieee80211_local *local, |
194 | struct sk_buff *skb, | |
195 | struct ieee80211_key *key) | |
f0706e82 JB |
196 | { |
197 | u32 klen; | |
730bd83b | 198 | u8 rc4key[3 + WLAN_KEY_LEN_WEP104]; |
f0706e82 | 199 | u8 keyidx; |
70217d7f HH |
200 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; |
201 | unsigned int hdrlen; | |
f0706e82 JB |
202 | size_t len; |
203 | int ret = 0; | |
204 | ||
70217d7f | 205 | if (!ieee80211_has_protected(hdr->frame_control)) |
f0706e82 JB |
206 | return -1; |
207 | ||
70217d7f | 208 | hdrlen = ieee80211_hdrlen(hdr->frame_control); |
4325f6ca | 209 | if (skb->len < hdrlen + IEEE80211_WEP_IV_LEN + IEEE80211_WEP_ICV_LEN) |
f0706e82 JB |
210 | return -1; |
211 | ||
4325f6ca | 212 | len = skb->len - hdrlen - IEEE80211_WEP_IV_LEN - IEEE80211_WEP_ICV_LEN; |
f0706e82 JB |
213 | |
214 | keyidx = skb->data[hdrlen + 3] >> 6; | |
215 | ||
97359d12 | 216 | if (!key || keyidx != key->conf.keyidx) |
f0706e82 JB |
217 | return -1; |
218 | ||
8f20fc24 | 219 | klen = 3 + key->conf.keylen; |
f0706e82 | 220 | |
f0706e82 JB |
221 | /* Prepend 24-bit IV to RC4 key */ |
222 | memcpy(rc4key, skb->data + hdrlen, 3); | |
223 | ||
224 | /* Copy rest of the WEP key (the secret part) */ | |
8f20fc24 | 225 | memcpy(rc4key + 3, key->conf.key, key->conf.keylen); |
f0706e82 | 226 | |
5fdb3735 | 227 | if (ieee80211_wep_decrypt_data(&local->wep_rx_ctx, rc4key, klen, |
4325f6ca JB |
228 | skb->data + hdrlen + |
229 | IEEE80211_WEP_IV_LEN, len)) | |
f0706e82 | 230 | ret = -1; |
f0706e82 | 231 | |
f0706e82 | 232 | /* Trim ICV */ |
4325f6ca | 233 | skb_trim(skb, skb->len - IEEE80211_WEP_ICV_LEN); |
f0706e82 JB |
234 | |
235 | /* Remove IV */ | |
4325f6ca JB |
236 | memmove(skb->data + IEEE80211_WEP_IV_LEN, skb->data, hdrlen); |
237 | skb_pull(skb, IEEE80211_WEP_IV_LEN); | |
f0706e82 JB |
238 | |
239 | return ret; | |
240 | } | |
241 | ||
9ae54c84 | 242 | ieee80211_rx_result |
5cf121c3 | 243 | ieee80211_crypto_wep_decrypt(struct ieee80211_rx_data *rx) |
4f0d18e2 | 244 | { |
eb9fb5b8 JB |
245 | struct sk_buff *skb = rx->skb; |
246 | struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); | |
247 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; | |
a8286911 | 248 | __le16 fc = hdr->frame_control; |
358c8d9d | 249 | |
a8286911 | 250 | if (!ieee80211_is_data(fc) && !ieee80211_is_auth(fc)) |
9ae54c84 | 251 | return RX_CONTINUE; |
4f0d18e2 | 252 | |
eb9fb5b8 | 253 | if (!(status->flag & RX_FLAG_DECRYPTED)) { |
a8286911 JB |
254 | if (skb_linearize(rx->skb)) |
255 | return RX_DROP_UNUSABLE; | |
f4ea83dd | 256 | if (ieee80211_wep_decrypt(rx->local, rx->skb, rx->key)) |
e4c26add | 257 | return RX_DROP_UNUSABLE; |
eb9fb5b8 | 258 | } else if (!(status->flag & RX_FLAG_IV_STRIPPED)) { |
4325f6ca JB |
259 | if (!pskb_may_pull(rx->skb, ieee80211_hdrlen(fc) + |
260 | IEEE80211_WEP_IV_LEN)) | |
a8286911 | 261 | return RX_DROP_UNUSABLE; |
4f0d18e2 JB |
262 | ieee80211_wep_remove_iv(rx->local, rx->skb, rx->key); |
263 | /* remove ICV */ | |
cef0acd4 DS |
264 | if (!(status->flag & RX_FLAG_ICV_STRIPPED) && |
265 | pskb_trim(rx->skb, rx->skb->len - IEEE80211_WEP_ICV_LEN)) | |
a8286911 | 266 | return RX_DROP_UNUSABLE; |
4f0d18e2 JB |
267 | } |
268 | ||
9ae54c84 | 269 | return RX_CONTINUE; |
4f0d18e2 | 270 | } |
6a22a59d | 271 | |
5cf121c3 | 272 | static int wep_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) |
6a22a59d | 273 | { |
e039fa4a | 274 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); |
ee70108f | 275 | struct ieee80211_key_conf *hw_key = info->control.hw_key; |
e039fa4a | 276 | |
ee70108f | 277 | if (!hw_key) { |
c9cf0122 JB |
278 | if (ieee80211_wep_encrypt(tx->local, skb, tx->key->conf.key, |
279 | tx->key->conf.keylen, | |
280 | tx->key->conf.keyidx)) | |
6a22a59d | 281 | return -1; |
ee70108f JD |
282 | } else if ((hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) || |
283 | (hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { | |
813d7669 JB |
284 | if (!ieee80211_wep_add_iv(tx->local, skb, |
285 | tx->key->conf.keylen, | |
286 | tx->key->conf.keyidx)) | |
287 | return -1; | |
288 | } | |
289 | ||
6a22a59d JB |
290 | return 0; |
291 | } | |
292 | ||
9ae54c84 | 293 | ieee80211_tx_result |
5cf121c3 | 294 | ieee80211_crypto_wep_encrypt(struct ieee80211_tx_data *tx) |
6a22a59d | 295 | { |
2de8e0d9 | 296 | struct sk_buff *skb; |
c6a1fa12 | 297 | |
5cf121c3 | 298 | ieee80211_tx_set_protected(tx); |
6a22a59d | 299 | |
252b86c4 | 300 | skb_queue_walk(&tx->skbs, skb) { |
2de8e0d9 JB |
301 | if (wep_encrypt_skb(tx, skb) < 0) { |
302 | I802_DEBUG_INC(tx->local->tx_handlers_drop_wep); | |
303 | return TX_DROP; | |
6a22a59d | 304 | } |
252b86c4 | 305 | } |
6a22a59d | 306 | |
9ae54c84 | 307 | return TX_CONTINUE; |
6a22a59d | 308 | } |