Merge tag 'for-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/pateldipen19...
[linux-block.git] / net / mac80211 / wep.c
CommitLineData
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.
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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>
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19
20#include <net/mac80211.h>
21#include "ieee80211_i.h"
22#include "wep.h"
23
24
4a65cc24 25void ieee80211_wep_init(struct ieee80211_local *local)
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26{
27 /* start WEP IV from a random value */
4325f6ca 28 get_random_bytes(&local->wep_iv, IEEE80211_WEP_IV_LEN);
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29}
30
c6a1fa12 31static inline bool ieee80211_wep_weak_iv(u32 iv, int keylen)
f0706e82 32{
c6a1fa12
JB
33 /*
34 * Fluhrer, Mantin, and Shamir have reported weaknesses in the
f0706e82 35 * key scheduling algorithm of RC4. At least IVs (KeyByte + 3,
c6a1fa12
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36 * 0xff, N) can be used to speedup attacks, so avoid using them.
37 */
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JB
38 if ((iv & 0xff00) == 0xff00) {
39 u8 B = (iv >> 16) & 0xff;
40 if (B >= 3 && B < 3 + keylen)
c6a1fa12 41 return true;
f0706e82 42 }
c6a1fa12 43 return false;
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44}
45
46
4f0d18e2 47static void ieee80211_wep_get_iv(struct ieee80211_local *local,
c9cf0122 48 int keylen, int keyidx, u8 *iv)
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49{
50 local->wep_iv++;
c9cf0122 51 if (ieee80211_wep_weak_iv(local->wep_iv, keylen))
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52 local->wep_iv += 0x0100;
53
54 if (!iv)
55 return;
56
57 *iv++ = (local->wep_iv >> 16) & 0xff;
58 *iv++ = (local->wep_iv >> 8) & 0xff;
59 *iv++ = local->wep_iv & 0xff;
c9cf0122 60 *iv++ = keyidx << 6;
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61}
62
63
6a22a59d
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64static u8 *ieee80211_wep_add_iv(struct ieee80211_local *local,
65 struct sk_buff *skb,
c9cf0122 66 int keylen, int keyidx)
f0706e82 67{
70217d7f 68 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
ee70108f 69 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
70217d7f 70 unsigned int hdrlen;
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71 u8 *newhdr;
72
70217d7f 73 hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
f0706e82 74
47b4e1fc 75 if (WARN_ON(skb_headroom(skb) < IEEE80211_WEP_IV_LEN))
23c0752a 76 return NULL;
f0706e82 77
70217d7f 78 hdrlen = ieee80211_hdrlen(hdr->frame_control);
4325f6ca
JB
79 newhdr = skb_push(skb, IEEE80211_WEP_IV_LEN);
80 memmove(newhdr, newhdr + IEEE80211_WEP_IV_LEN, hdrlen);
ee70108f
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81
82 /* the HW only needs room for the IV, but not the actual IV */
83 if (info->control.hw_key &&
84 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
85 return newhdr + hdrlen;
86
c9cf0122 87 ieee80211_wep_get_iv(local, keylen, keyidx, newhdr + hdrlen);
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88 return newhdr + hdrlen;
89}
90
91
4f0d18e2
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92static void ieee80211_wep_remove_iv(struct ieee80211_local *local,
93 struct sk_buff *skb,
94 struct ieee80211_key *key)
f0706e82 95{
70217d7f
HH
96 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
97 unsigned int hdrlen;
f0706e82 98
70217d7f 99 hdrlen = ieee80211_hdrlen(hdr->frame_control);
4325f6ca
JB
100 memmove(skb->data + IEEE80211_WEP_IV_LEN, skb->data, hdrlen);
101 skb_pull(skb, IEEE80211_WEP_IV_LEN);
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102}
103
104
105/* Perform WEP encryption using given key. data buffer must have tailroom
106 * for 4-byte ICV. data_len must not include this ICV. Note: this function
107 * does _not_ add IV. data = RC4(data | CRC32(data)) */
5fdb3735 108int ieee80211_wep_encrypt_data(struct arc4_ctx *ctx, u8 *rc4key,
3473187d 109 size_t klen, u8 *data, size_t data_len)
f0706e82 110{
860c6e6a 111 __le32 icv;
3473187d 112
860c6e6a
IK
113 icv = cpu_to_le32(~crc32_le(~0, data, data_len));
114 put_unaligned(icv, (__le32 *)(data + data_len));
f0706e82 115
5fdb3735
AB
116 arc4_setkey(ctx, rc4key, klen);
117 arc4_crypt(ctx, data, data, data_len + IEEE80211_WEP_ICV_LEN);
118 memzero_explicit(ctx, sizeof(*ctx));
3473187d
JL
119
120 return 0;
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121}
122
123
124/* Perform WEP encryption on given skb. 4 bytes of extra space (IV) in the
125 * beginning of the buffer 4 bytes of extra space (ICV) in the end of the
126 * buffer will be added. Both IV and ICV will be transmitted, so the
127 * payload length increases with 8 bytes.
128 *
129 * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
130 */
fffd0934
JB
131int ieee80211_wep_encrypt(struct ieee80211_local *local,
132 struct sk_buff *skb,
133 const u8 *key, int keylen, int keyidx)
f0706e82 134{
c9cf0122 135 u8 *iv;
f0706e82 136 size_t len;
c9cf0122 137 u8 rc4key[3 + WLAN_KEY_LEN_WEP104];
f0706e82 138
47b4e1fc
JD
139 if (WARN_ON(skb_tailroom(skb) < IEEE80211_WEP_ICV_LEN))
140 return -1;
141
c9cf0122
JB
142 iv = ieee80211_wep_add_iv(local, skb, keylen, keyidx);
143 if (!iv)
f0706e82 144 return -1;
f0706e82 145
4325f6ca 146 len = skb->len - (iv + IEEE80211_WEP_IV_LEN - skb->data);
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147
148 /* Prepend 24-bit IV to RC4 key */
149 memcpy(rc4key, iv, 3);
150
151 /* Copy rest of the WEP key (the secret part) */
c9cf0122 152 memcpy(rc4key + 3, key, keylen);
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153
154 /* Add room for ICV */
4325f6ca 155 skb_put(skb, IEEE80211_WEP_ICV_LEN);
f0706e82 156
5fdb3735 157 return ieee80211_wep_encrypt_data(&local->wep_tx_ctx, rc4key, keylen + 3,
4325f6ca 158 iv + IEEE80211_WEP_IV_LEN, len);
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159}
160
161
162/* Perform WEP decryption using given key. data buffer includes encrypted
163 * payload, including 4-byte ICV, but _not_ IV. data_len must not include ICV.
164 * Return 0 on success and -1 on ICV mismatch. */
5fdb3735 165int ieee80211_wep_decrypt_data(struct arc4_ctx *ctx, u8 *rc4key,
f0706e82
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166 size_t klen, u8 *data, size_t data_len)
167{
f0706e82 168 __le32 crc;
3473187d 169
5fdb3735
AB
170 arc4_setkey(ctx, rc4key, klen);
171 arc4_crypt(ctx, data, data, data_len + IEEE80211_WEP_ICV_LEN);
172 memzero_explicit(ctx, sizeof(*ctx));
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173
174 crc = cpu_to_le32(~crc32_le(~0, data, data_len));
4325f6ca 175 if (memcmp(&crc, data + data_len, IEEE80211_WEP_ICV_LEN) != 0)
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176 /* ICV mismatch */
177 return -1;
178
179 return 0;
180}
181
182
183/* Perform WEP decryption on given skb. Buffer includes whole WEP part of
184 * the frame: IV (4 bytes), encrypted payload (including SNAP header),
185 * ICV (4 bytes). skb->len includes both IV and ICV.
186 *
187 * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
188 * failure. If frame is OK, IV and ICV will be removed, i.e., decrypted payload
189 * is moved to the beginning of the skb and skb length will be reduced.
190 */
c9cf0122
JB
191static int ieee80211_wep_decrypt(struct ieee80211_local *local,
192 struct sk_buff *skb,
193 struct ieee80211_key *key)
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194{
195 u32 klen;
730bd83b 196 u8 rc4key[3 + WLAN_KEY_LEN_WEP104];
f0706e82 197 u8 keyidx;
70217d7f
HH
198 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
199 unsigned int hdrlen;
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200 size_t len;
201 int ret = 0;
202
70217d7f 203 if (!ieee80211_has_protected(hdr->frame_control))
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204 return -1;
205
70217d7f 206 hdrlen = ieee80211_hdrlen(hdr->frame_control);
4325f6ca 207 if (skb->len < hdrlen + IEEE80211_WEP_IV_LEN + IEEE80211_WEP_ICV_LEN)
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208 return -1;
209
4325f6ca 210 len = skb->len - hdrlen - IEEE80211_WEP_IV_LEN - IEEE80211_WEP_ICV_LEN;
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211
212 keyidx = skb->data[hdrlen + 3] >> 6;
213
97359d12 214 if (!key || keyidx != key->conf.keyidx)
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215 return -1;
216
8f20fc24 217 klen = 3 + key->conf.keylen;
f0706e82 218
f0706e82
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219 /* Prepend 24-bit IV to RC4 key */
220 memcpy(rc4key, skb->data + hdrlen, 3);
221
222 /* Copy rest of the WEP key (the secret part) */
8f20fc24 223 memcpy(rc4key + 3, key->conf.key, key->conf.keylen);
f0706e82 224
5fdb3735 225 if (ieee80211_wep_decrypt_data(&local->wep_rx_ctx, rc4key, klen,
4325f6ca
JB
226 skb->data + hdrlen +
227 IEEE80211_WEP_IV_LEN, len))
f0706e82 228 ret = -1;
f0706e82 229
f0706e82 230 /* Trim ICV */
4325f6ca 231 skb_trim(skb, skb->len - IEEE80211_WEP_ICV_LEN);
f0706e82
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232
233 /* Remove IV */
4325f6ca
JB
234 memmove(skb->data + IEEE80211_WEP_IV_LEN, skb->data, hdrlen);
235 skb_pull(skb, IEEE80211_WEP_IV_LEN);
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236
237 return ret;
238}
239
9ae54c84 240ieee80211_rx_result
5cf121c3 241ieee80211_crypto_wep_decrypt(struct ieee80211_rx_data *rx)
4f0d18e2 242{
eb9fb5b8
JB
243 struct sk_buff *skb = rx->skb;
244 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
245 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
a8286911 246 __le16 fc = hdr->frame_control;
358c8d9d 247
a8286911 248 if (!ieee80211_is_data(fc) && !ieee80211_is_auth(fc))
9ae54c84 249 return RX_CONTINUE;
4f0d18e2 250
eb9fb5b8 251 if (!(status->flag & RX_FLAG_DECRYPTED)) {
a8286911
JB
252 if (skb_linearize(rx->skb))
253 return RX_DROP_UNUSABLE;
f4ea83dd 254 if (ieee80211_wep_decrypt(rx->local, rx->skb, rx->key))
e4c26add 255 return RX_DROP_UNUSABLE;
eb9fb5b8 256 } else if (!(status->flag & RX_FLAG_IV_STRIPPED)) {
4325f6ca
JB
257 if (!pskb_may_pull(rx->skb, ieee80211_hdrlen(fc) +
258 IEEE80211_WEP_IV_LEN))
a8286911 259 return RX_DROP_UNUSABLE;
4f0d18e2
JB
260 ieee80211_wep_remove_iv(rx->local, rx->skb, rx->key);
261 /* remove ICV */
cef0acd4
DS
262 if (!(status->flag & RX_FLAG_ICV_STRIPPED) &&
263 pskb_trim(rx->skb, rx->skb->len - IEEE80211_WEP_ICV_LEN))
a8286911 264 return RX_DROP_UNUSABLE;
4f0d18e2
JB
265 }
266
9ae54c84 267 return RX_CONTINUE;
4f0d18e2 268}
6a22a59d 269
5cf121c3 270static int wep_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
6a22a59d 271{
e039fa4a 272 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
ee70108f 273 struct ieee80211_key_conf *hw_key = info->control.hw_key;
e039fa4a 274
ee70108f 275 if (!hw_key) {
c9cf0122
JB
276 if (ieee80211_wep_encrypt(tx->local, skb, tx->key->conf.key,
277 tx->key->conf.keylen,
278 tx->key->conf.keyidx))
6a22a59d 279 return -1;
ee70108f
JD
280 } else if ((hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
281 (hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
813d7669
JB
282 if (!ieee80211_wep_add_iv(tx->local, skb,
283 tx->key->conf.keylen,
284 tx->key->conf.keyidx))
285 return -1;
286 }
287
6a22a59d
JB
288 return 0;
289}
290
9ae54c84 291ieee80211_tx_result
5cf121c3 292ieee80211_crypto_wep_encrypt(struct ieee80211_tx_data *tx)
6a22a59d 293{
2de8e0d9 294 struct sk_buff *skb;
c6a1fa12 295
5cf121c3 296 ieee80211_tx_set_protected(tx);
6a22a59d 297
252b86c4 298 skb_queue_walk(&tx->skbs, skb) {
2de8e0d9
JB
299 if (wep_encrypt_skb(tx, skb) < 0) {
300 I802_DEBUG_INC(tx->local->tx_handlers_drop_wep);
301 return TX_DROP;
6a22a59d 302 }
252b86c4 303 }
6a22a59d 304
9ae54c84 305 return TX_CONTINUE;
6a22a59d 306}