mac80211: config hw when going back on-channel
[linux-2.6.git] / net / 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 #include <linux/kernel.h>
10 #include <linux/bitops.h>
11 #include <linux/types.h>
12 #include <linux/netdevice.h>
13 #include <asm/unaligned.h>
14
15 #include <net/mac80211.h>
16 #include "driver-ops.h"
17 #include "key.h"
18 #include "tkip.h"
19 #include "wep.h"
20
21 #define PHASE1_LOOP_COUNT 8
22
23 /*
24  * 2-byte by 2-byte subset of the full AES S-box table; second part of this
25  * table is identical to first part but byte-swapped
26  */
27 static const u16 tkip_sbox[256] =
28 {
29         0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
30         0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
31         0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
32         0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
33         0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
34         0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
35         0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
36         0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
37         0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
38         0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
39         0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
40         0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
41         0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
42         0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
43         0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
44         0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
45         0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
46         0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
47         0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
48         0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
49         0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
50         0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
51         0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
52         0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
53         0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
54         0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
55         0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
56         0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
57         0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
58         0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
59         0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
60         0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
61 };
62
63 static u16 tkipS(u16 val)
64 {
65         return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]);
66 }
67
68 static u8 *write_tkip_iv(u8 *pos, u16 iv16)
69 {
70         *pos++ = iv16 >> 8;
71         *pos++ = ((iv16 >> 8) | 0x20) & 0x7f;
72         *pos++ = iv16 & 0xFF;
73         return pos;
74 }
75
76 /*
77  * P1K := Phase1(TA, TK, TSC)
78  * TA = transmitter address (48 bits)
79  * TK = dot11DefaultKeyValue or dot11KeyMappingValue (128 bits)
80  * TSC = TKIP sequence counter (48 bits, only 32 msb bits used)
81  * P1K: 80 bits
82  */
83 static void tkip_mixing_phase1(const u8 *tk, struct tkip_ctx *ctx,
84                                const u8 *ta, u32 tsc_IV32)
85 {
86         int i, j;
87         u16 *p1k = ctx->p1k;
88
89         p1k[0] = tsc_IV32 & 0xFFFF;
90         p1k[1] = tsc_IV32 >> 16;
91         p1k[2] = get_unaligned_le16(ta + 0);
92         p1k[3] = get_unaligned_le16(ta + 2);
93         p1k[4] = get_unaligned_le16(ta + 4);
94
95         for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
96                 j = 2 * (i & 1);
97                 p1k[0] += tkipS(p1k[4] ^ get_unaligned_le16(tk + 0 + j));
98                 p1k[1] += tkipS(p1k[0] ^ get_unaligned_le16(tk + 4 + j));
99                 p1k[2] += tkipS(p1k[1] ^ get_unaligned_le16(tk + 8 + j));
100                 p1k[3] += tkipS(p1k[2] ^ get_unaligned_le16(tk + 12 + j));
101                 p1k[4] += tkipS(p1k[3] ^ get_unaligned_le16(tk + 0 + j)) + i;
102         }
103         ctx->state = TKIP_STATE_PHASE1_DONE;
104         ctx->p1k_iv32 = tsc_IV32;
105 }
106
107 static void tkip_mixing_phase2(const u8 *tk, struct tkip_ctx *ctx,
108                                u16 tsc_IV16, u8 *rc4key)
109 {
110         u16 ppk[6];
111         const u16 *p1k = ctx->p1k;
112         int i;
113
114         ppk[0] = p1k[0];
115         ppk[1] = p1k[1];
116         ppk[2] = p1k[2];
117         ppk[3] = p1k[3];
118         ppk[4] = p1k[4];
119         ppk[5] = p1k[4] + tsc_IV16;
120
121         ppk[0] += tkipS(ppk[5] ^ get_unaligned_le16(tk + 0));
122         ppk[1] += tkipS(ppk[0] ^ get_unaligned_le16(tk + 2));
123         ppk[2] += tkipS(ppk[1] ^ get_unaligned_le16(tk + 4));
124         ppk[3] += tkipS(ppk[2] ^ get_unaligned_le16(tk + 6));
125         ppk[4] += tkipS(ppk[3] ^ get_unaligned_le16(tk + 8));
126         ppk[5] += tkipS(ppk[4] ^ get_unaligned_le16(tk + 10));
127         ppk[0] += ror16(ppk[5] ^ get_unaligned_le16(tk + 12), 1);
128         ppk[1] += ror16(ppk[0] ^ get_unaligned_le16(tk + 14), 1);
129         ppk[2] += ror16(ppk[1], 1);
130         ppk[3] += ror16(ppk[2], 1);
131         ppk[4] += ror16(ppk[3], 1);
132         ppk[5] += ror16(ppk[4], 1);
133
134         rc4key = write_tkip_iv(rc4key, tsc_IV16);
135         *rc4key++ = ((ppk[5] ^ get_unaligned_le16(tk)) >> 1) & 0xFF;
136
137         for (i = 0; i < 6; i++)
138                 put_unaligned_le16(ppk[i], rc4key + 2 * i);
139 }
140
141 /* Add TKIP IV and Ext. IV at @pos. @iv0, @iv1, and @iv2 are the first octets
142  * of the IV. Returns pointer to the octet following IVs (i.e., beginning of
143  * the packet payload). */
144 u8 *ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key)
145 {
146         lockdep_assert_held(&key->u.tkip.txlock);
147
148         pos = write_tkip_iv(pos, key->u.tkip.tx.iv16);
149         *pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */;
150         put_unaligned_le32(key->u.tkip.tx.iv32, pos);
151         return pos + 4;
152 }
153
154 static void ieee80211_compute_tkip_p1k(struct ieee80211_key *key, u32 iv32)
155 {
156         struct ieee80211_sub_if_data *sdata = key->sdata;
157         struct tkip_ctx *ctx = &key->u.tkip.tx;
158         const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
159
160         lockdep_assert_held(&key->u.tkip.txlock);
161
162         /*
163          * Update the P1K when the IV32 is different from the value it
164          * had when we last computed it (or when not initialised yet).
165          * This might flip-flop back and forth if packets are processed
166          * out-of-order due to the different ACs, but then we have to
167          * just compute the P1K more often.
168          */
169         if (ctx->p1k_iv32 != iv32 || ctx->state == TKIP_STATE_NOT_INIT)
170                 tkip_mixing_phase1(tk, ctx, sdata->vif.addr, iv32);
171 }
172
173 void ieee80211_get_tkip_p1k_iv(struct ieee80211_key_conf *keyconf,
174                                u32 iv32, u16 *p1k)
175 {
176         struct ieee80211_key *key = (struct ieee80211_key *)
177                         container_of(keyconf, struct ieee80211_key, conf);
178         struct tkip_ctx *ctx = &key->u.tkip.tx;
179         unsigned long flags;
180
181         spin_lock_irqsave(&key->u.tkip.txlock, flags);
182         ieee80211_compute_tkip_p1k(key, iv32);
183         memcpy(p1k, ctx->p1k, sizeof(ctx->p1k));
184         spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
185 }
186 EXPORT_SYMBOL(ieee80211_get_tkip_p1k_iv);
187
188 void ieee80211_get_tkip_rx_p1k(struct ieee80211_key_conf *keyconf,
189                                const u8 *ta, u32 iv32, u16 *p1k)
190 {
191         const u8 *tk = &keyconf->key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
192         struct tkip_ctx ctx;
193
194         tkip_mixing_phase1(tk, &ctx, ta, iv32);
195         memcpy(p1k, ctx.p1k, sizeof(ctx.p1k));
196 }
197 EXPORT_SYMBOL(ieee80211_get_tkip_rx_p1k);
198
199 void ieee80211_get_tkip_p2k(struct ieee80211_key_conf *keyconf,
200                             struct sk_buff *skb, u8 *p2k)
201 {
202         struct ieee80211_key *key = (struct ieee80211_key *)
203                         container_of(keyconf, struct ieee80211_key, conf);
204         const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
205         struct tkip_ctx *ctx = &key->u.tkip.tx;
206         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
207         const u8 *data = (u8 *)hdr + ieee80211_hdrlen(hdr->frame_control);
208         u32 iv32 = get_unaligned_le32(&data[4]);
209         u16 iv16 = data[2] | (data[0] << 8);
210         unsigned long flags;
211
212         spin_lock_irqsave(&key->u.tkip.txlock, flags);
213         ieee80211_compute_tkip_p1k(key, iv32);
214         tkip_mixing_phase2(tk, ctx, iv16, p2k);
215         spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
216 }
217 EXPORT_SYMBOL(ieee80211_get_tkip_p2k);
218
219 /*
220  * Encrypt packet payload with TKIP using @key. @pos is a pointer to the
221  * beginning of the buffer containing payload. This payload must include
222  * the IV/Ext.IV and space for (taildroom) four octets for ICV.
223  * @payload_len is the length of payload (_not_ including IV/ICV length).
224  * @ta is the transmitter addresses.
225  */
226 int ieee80211_tkip_encrypt_data(struct crypto_cipher *tfm,
227                                 struct ieee80211_key *key,
228                                 struct sk_buff *skb,
229                                 u8 *payload, size_t payload_len)
230 {
231         u8 rc4key[16];
232
233         ieee80211_get_tkip_p2k(&key->conf, skb, rc4key);
234
235         return ieee80211_wep_encrypt_data(tfm, rc4key, 16,
236                                           payload, payload_len);
237 }
238
239 /* Decrypt packet payload with TKIP using @key. @pos is a pointer to the
240  * beginning of the buffer containing IEEE 802.11 header payload, i.e.,
241  * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the
242  * length of payload, including IV, Ext. IV, MIC, ICV.  */
243 int ieee80211_tkip_decrypt_data(struct crypto_cipher *tfm,
244                                 struct ieee80211_key *key,
245                                 u8 *payload, size_t payload_len, u8 *ta,
246                                 u8 *ra, int only_iv, int queue,
247                                 u32 *out_iv32, u16 *out_iv16)
248 {
249         u32 iv32;
250         u32 iv16;
251         u8 rc4key[16], keyid, *pos = payload;
252         int res;
253         const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
254
255         if (payload_len < 12)
256                 return -1;
257
258         iv16 = (pos[0] << 8) | pos[2];
259         keyid = pos[3];
260         iv32 = get_unaligned_le32(pos + 4);
261         pos += 8;
262 #ifdef CONFIG_MAC80211_TKIP_DEBUG
263         {
264                 int i;
265                 printk(KERN_DEBUG "TKIP decrypt: data(len=%zd)", payload_len);
266                 for (i = 0; i < payload_len; i++)
267                         printk(" %02x", payload[i]);
268                 printk("\n");
269                 printk(KERN_DEBUG "TKIP decrypt: iv16=%04x iv32=%08x\n",
270                        iv16, iv32);
271         }
272 #endif
273
274         if (!(keyid & (1 << 5)))
275                 return TKIP_DECRYPT_NO_EXT_IV;
276
277         if ((keyid >> 6) != key->conf.keyidx)
278                 return TKIP_DECRYPT_INVALID_KEYIDX;
279
280         if (key->u.tkip.rx[queue].state != TKIP_STATE_NOT_INIT &&
281             (iv32 < key->u.tkip.rx[queue].iv32 ||
282              (iv32 == key->u.tkip.rx[queue].iv32 &&
283               iv16 <= key->u.tkip.rx[queue].iv16))) {
284 #ifdef CONFIG_MAC80211_TKIP_DEBUG
285                 printk(KERN_DEBUG "TKIP replay detected for RX frame from "
286                        "%pM (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n",
287                        ta,
288                        iv32, iv16, key->u.tkip.rx[queue].iv32,
289                        key->u.tkip.rx[queue].iv16);
290 #endif
291                 return TKIP_DECRYPT_REPLAY;
292         }
293
294         if (only_iv) {
295                 res = TKIP_DECRYPT_OK;
296                 key->u.tkip.rx[queue].state = TKIP_STATE_PHASE1_HW_UPLOADED;
297                 goto done;
298         }
299
300         if (key->u.tkip.rx[queue].state == TKIP_STATE_NOT_INIT ||
301             key->u.tkip.rx[queue].iv32 != iv32) {
302                 /* IV16 wrapped around - perform TKIP phase 1 */
303                 tkip_mixing_phase1(tk, &key->u.tkip.rx[queue], ta, iv32);
304 #ifdef CONFIG_MAC80211_TKIP_DEBUG
305                 {
306                         int i;
307                         u8 key_offset = NL80211_TKIP_DATA_OFFSET_ENCR_KEY;
308                         printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%pM"
309                                " TK=", ta);
310                         for (i = 0; i < 16; i++)
311                                 printk("%02x ",
312                                        key->conf.key[key_offset + i]);
313                         printk("\n");
314                         printk(KERN_DEBUG "TKIP decrypt: P1K=");
315                         for (i = 0; i < 5; i++)
316                                 printk("%04x ", key->u.tkip.rx[queue].p1k[i]);
317                         printk("\n");
318                 }
319 #endif
320         }
321         if (key->local->ops->update_tkip_key &&
322             key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE &&
323             key->u.tkip.rx[queue].state != TKIP_STATE_PHASE1_HW_UPLOADED) {
324                 struct ieee80211_sub_if_data *sdata = key->sdata;
325
326                 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
327                         sdata = container_of(key->sdata->bss,
328                                         struct ieee80211_sub_if_data, u.ap);
329                 drv_update_tkip_key(key->local, sdata, &key->conf, key->sta,
330                                 iv32, key->u.tkip.rx[queue].p1k);
331                 key->u.tkip.rx[queue].state = TKIP_STATE_PHASE1_HW_UPLOADED;
332         }
333
334         tkip_mixing_phase2(tk, &key->u.tkip.rx[queue], iv16, rc4key);
335 #ifdef CONFIG_MAC80211_TKIP_DEBUG
336         {
337                 int i;
338                 printk(KERN_DEBUG "TKIP decrypt: Phase2 rc4key=");
339                 for (i = 0; i < 16; i++)
340                         printk("%02x ", rc4key[i]);
341                 printk("\n");
342         }
343 #endif
344
345         res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12);
346  done:
347         if (res == TKIP_DECRYPT_OK) {
348                 /*
349                  * Record previously received IV, will be copied into the
350                  * key information after MIC verification. It is possible
351                  * that we don't catch replays of fragments but that's ok
352                  * because the Michael MIC verication will then fail.
353                  */
354                 *out_iv32 = iv32;
355                 *out_iv16 = iv16;
356         }
357
358         return res;
359 }