add git checkout support
[openwrt/openwrt.git] / package / mac80211 / src / mac80211 / tkip.c
1 /*
2 * Copyright 2002-2004, Instant802 Networks, Inc.
3 * Copyright 2005, Devicescape Software, Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/types.h>
12 #include <linux/netdevice.h>
13
14 #include <net/mac80211.h>
15 #include "ieee80211_key.h"
16 #include "tkip.h"
17 #include "wep.h"
18
19
20 /* TKIP key mixing functions */
21
22
23 #define PHASE1_LOOP_COUNT 8
24
25
26 /* 2-byte by 2-byte subset of the full AES S-box table; second part of this
27 * table is identical to first part but byte-swapped */
28 static const u16 tkip_sbox[256] =
29 {
30 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
31 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
32 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
33 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
34 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
35 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
36 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
37 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
38 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
39 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
40 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
41 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
42 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
43 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
44 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
45 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
46 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
47 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
48 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
49 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
50 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
51 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
52 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
53 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
54 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
55 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
56 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
57 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
58 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
59 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
60 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
61 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
62 };
63
64
65 static inline u16 Mk16(u8 x, u8 y)
66 {
67 return ((u16) x << 8) | (u16) y;
68 }
69
70
71 static inline u8 Hi8(u16 v)
72 {
73 return v >> 8;
74 }
75
76
77 static inline u8 Lo8(u16 v)
78 {
79 return v & 0xff;
80 }
81
82
83 static inline u16 Hi16(u32 v)
84 {
85 return v >> 16;
86 }
87
88
89 static inline u16 Lo16(u32 v)
90 {
91 return v & 0xffff;
92 }
93
94
95 static inline u16 RotR1(u16 v)
96 {
97 return (v >> 1) | ((v & 0x0001) << 15);
98 }
99
100
101 static inline u16 tkip_S(u16 val)
102 {
103 u16 a = tkip_sbox[Hi8(val)];
104
105 return tkip_sbox[Lo8(val)] ^ Hi8(a) ^ (Lo8(a) << 8);
106 }
107
108
109
110 /* P1K := Phase1(TA, TK, TSC)
111 * TA = transmitter address (48 bits)
112 * TK = dot11DefaultKeyValue or dot11KeyMappingValue (128 bits)
113 * TSC = TKIP sequence counter (48 bits, only 32 msb bits used)
114 * P1K: 80 bits
115 */
116 static void tkip_mixing_phase1(const u8 *ta, const u8 *tk, u32 tsc_IV32,
117 u16 *p1k)
118 {
119 int i, j;
120
121 p1k[0] = Lo16(tsc_IV32);
122 p1k[1] = Hi16(tsc_IV32);
123 p1k[2] = Mk16(ta[1], ta[0]);
124 p1k[3] = Mk16(ta[3], ta[2]);
125 p1k[4] = Mk16(ta[5], ta[4]);
126
127 for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
128 j = 2 * (i & 1);
129 p1k[0] += tkip_S(p1k[4] ^ Mk16(tk[ 1 + j], tk[ 0 + j]));
130 p1k[1] += tkip_S(p1k[0] ^ Mk16(tk[ 5 + j], tk[ 4 + j]));
131 p1k[2] += tkip_S(p1k[1] ^ Mk16(tk[ 9 + j], tk[ 8 + j]));
132 p1k[3] += tkip_S(p1k[2] ^ Mk16(tk[13 + j], tk[12 + j]));
133 p1k[4] += tkip_S(p1k[3] ^ Mk16(tk[ 1 + j], tk[ 0 + j])) + i;
134 }
135 }
136
137
138 static void tkip_mixing_phase2(const u16 *p1k, const u8 *tk, u16 tsc_IV16,
139 u8 *rc4key)
140 {
141 u16 ppk[6];
142 int i;
143
144 ppk[0] = p1k[0];
145 ppk[1] = p1k[1];
146 ppk[2] = p1k[2];
147 ppk[3] = p1k[3];
148 ppk[4] = p1k[4];
149 ppk[5] = p1k[4] + tsc_IV16;
150
151 ppk[0] += tkip_S(ppk[5] ^ Mk16(tk[ 1], tk[ 0]));
152 ppk[1] += tkip_S(ppk[0] ^ Mk16(tk[ 3], tk[ 2]));
153 ppk[2] += tkip_S(ppk[1] ^ Mk16(tk[ 5], tk[ 4]));
154 ppk[3] += tkip_S(ppk[2] ^ Mk16(tk[ 7], tk[ 6]));
155 ppk[4] += tkip_S(ppk[3] ^ Mk16(tk[ 9], tk[ 8]));
156 ppk[5] += tkip_S(ppk[4] ^ Mk16(tk[11], tk[10]));
157 ppk[0] += RotR1(ppk[5] ^ Mk16(tk[13], tk[12]));
158 ppk[1] += RotR1(ppk[0] ^ Mk16(tk[15], tk[14]));
159 ppk[2] += RotR1(ppk[1]);
160 ppk[3] += RotR1(ppk[2]);
161 ppk[4] += RotR1(ppk[3]);
162 ppk[5] += RotR1(ppk[4]);
163
164 rc4key[0] = Hi8(tsc_IV16);
165 rc4key[1] = (Hi8(tsc_IV16) | 0x20) & 0x7f;
166 rc4key[2] = Lo8(tsc_IV16);
167 rc4key[3] = Lo8((ppk[5] ^ Mk16(tk[1], tk[0])) >> 1);
168
169 for (i = 0; i < 6; i++) {
170 rc4key[4 + 2 * i] = Lo8(ppk[i]);
171 rc4key[5 + 2 * i] = Hi8(ppk[i]);
172 }
173 }
174
175
176 /* Add TKIP IV and Ext. IV at @pos. @iv0, @iv1, and @iv2 are the first octets
177 * of the IV. Returns pointer to the octet following IVs (i.e., beginning of
178 * the packet payload). */
179 u8 * ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key,
180 u8 iv0, u8 iv1, u8 iv2)
181 {
182 *pos++ = iv0;
183 *pos++ = iv1;
184 *pos++ = iv2;
185 *pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */;
186 *pos++ = key->u.tkip.iv32 & 0xff;
187 *pos++ = (key->u.tkip.iv32 >> 8) & 0xff;
188 *pos++ = (key->u.tkip.iv32 >> 16) & 0xff;
189 *pos++ = (key->u.tkip.iv32 >> 24) & 0xff;
190 return pos;
191 }
192
193
194 void ieee80211_tkip_gen_phase1key(struct ieee80211_key *key, u8 *ta,
195 u16 *phase1key)
196 {
197 tkip_mixing_phase1(ta, &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY],
198 key->u.tkip.iv32, phase1key);
199 }
200
201 void ieee80211_tkip_gen_rc4key(struct ieee80211_key *key, u8 *ta,
202 u8 *rc4key)
203 {
204 /* Calculate per-packet key */
205 if (key->u.tkip.iv16 == 0 || !key->u.tkip.tx_initialized) {
206 /* IV16 wrapped around - perform TKIP phase 1 */
207 tkip_mixing_phase1(ta, &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY],
208 key->u.tkip.iv32, key->u.tkip.p1k);
209 key->u.tkip.tx_initialized = 1;
210 }
211
212 tkip_mixing_phase2(key->u.tkip.p1k,
213 &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY],
214 key->u.tkip.iv16, rc4key);
215 }
216
217 /* Encrypt packet payload with TKIP using @key. @pos is a pointer to the
218 * beginning of the buffer containing payload. This payload must include
219 * headroom of eight octets for IV and Ext. IV and taildroom of four octets
220 * for ICV. @payload_len is the length of payload (_not_ including extra
221 * headroom and tailroom). @ta is the transmitter addresses. */
222 void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm,
223 struct ieee80211_key *key,
224 u8 *pos, size_t payload_len, u8 *ta)
225 {
226 u8 rc4key[16];
227
228 ieee80211_tkip_gen_rc4key(key, ta, rc4key);
229 pos = ieee80211_tkip_add_iv(pos, key, rc4key[0], rc4key[1], rc4key[2]);
230 ieee80211_wep_encrypt_data(tfm, rc4key, 16, pos, payload_len);
231 }
232
233
234 /* Decrypt packet payload with TKIP using @key. @pos is a pointer to the
235 * beginning of the buffer containing IEEE 802.11 header payload, i.e.,
236 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the
237 * length of payload, including IV, Ext. IV, MIC, ICV. */
238 int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,
239 struct ieee80211_key *key,
240 u8 *payload, size_t payload_len, u8 *ta,
241 int only_iv, int queue,
242 u32 *out_iv32, u16 *out_iv16)
243 {
244 u32 iv32;
245 u32 iv16;
246 u8 rc4key[16], keyid, *pos = payload;
247 int res;
248
249 if (payload_len < 12)
250 return -1;
251
252 iv16 = (pos[0] << 8) | pos[2];
253 keyid = pos[3];
254 iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24);
255 pos += 8;
256 #ifdef CONFIG_TKIP_DEBUG
257 {
258 int i;
259 printk(KERN_DEBUG "TKIP decrypt: data(len=%zd)", payload_len);
260 for (i = 0; i < payload_len; i++)
261 printk(" %02x", payload[i]);
262 printk("\n");
263 printk(KERN_DEBUG "TKIP decrypt: iv16=%04x iv32=%08x\n",
264 iv16, iv32);
265 }
266 #endif /* CONFIG_TKIP_DEBUG */
267
268 if (!(keyid & (1 << 5)))
269 return TKIP_DECRYPT_NO_EXT_IV;
270
271 if ((keyid >> 6) != key->conf.keyidx)
272 return TKIP_DECRYPT_INVALID_KEYIDX;
273
274 if (key->u.tkip.rx_initialized[queue] &&
275 (iv32 < key->u.tkip.iv32_rx[queue] ||
276 (iv32 == key->u.tkip.iv32_rx[queue] &&
277 iv16 <= key->u.tkip.iv16_rx[queue]))) {
278 #ifdef CONFIG_TKIP_DEBUG
279 printk(KERN_DEBUG "TKIP replay detected for RX frame from "
280 MAC_FMT " (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n",
281 MAC_ARG(ta),
282 iv32, iv16, key->u.tkip.iv32_rx[queue],
283 key->u.tkip.iv16_rx[queue]);
284 #endif /* CONFIG_TKIP_DEBUG */
285 return TKIP_DECRYPT_REPLAY;
286 }
287
288 if (only_iv) {
289 res = TKIP_DECRYPT_OK;
290 key->u.tkip.rx_initialized[queue] = 1;
291 goto done;
292 }
293
294 if (!key->u.tkip.rx_initialized[queue] ||
295 key->u.tkip.iv32_rx[queue] != iv32) {
296 key->u.tkip.rx_initialized[queue] = 1;
297 /* IV16 wrapped around - perform TKIP phase 1 */
298 tkip_mixing_phase1(ta, &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY],
299 iv32, key->u.tkip.p1k_rx[queue]);
300 #ifdef CONFIG_TKIP_DEBUG
301 {
302 int i;
303 printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=" MAC_FMT
304 " TK=", MAC_ARG(ta));
305 for (i = 0; i < 16; i++)
306 printk("%02x ",
307 key->conf.key[
308 ALG_TKIP_TEMP_ENCR_KEY + i]);
309 printk("\n");
310 printk(KERN_DEBUG "TKIP decrypt: P1K=");
311 for (i = 0; i < 5; i++)
312 printk("%04x ", key->u.tkip.p1k_rx[queue][i]);
313 printk("\n");
314 }
315 #endif /* CONFIG_TKIP_DEBUG */
316 }
317
318 tkip_mixing_phase2(key->u.tkip.p1k_rx[queue],
319 &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY],
320 iv16, rc4key);
321 #ifdef CONFIG_TKIP_DEBUG
322 {
323 int i;
324 printk(KERN_DEBUG "TKIP decrypt: Phase2 rc4key=");
325 for (i = 0; i < 16; i++)
326 printk("%02x ", rc4key[i]);
327 printk("\n");
328 }
329 #endif /* CONFIG_TKIP_DEBUG */
330
331 res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12);
332 done:
333 if (res == TKIP_DECRYPT_OK) {
334 /*
335 * Record previously received IV, will be copied into the
336 * key information after MIC verification. It is possible
337 * that we don't catch replays of fragments but that's ok
338 * because the Michael MIC verication will then fail.
339 */
340 *out_iv32 = iv32;
341 *out_iv16 = iv16;
342 }
343
344 return res;
345 }
346
347