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mac80211: Fix TKIP replay protection immediately after key setup
[mirror_ubuntu-bionic-kernel.git] / net / mac80211 / tkip.c
CommitLineData
f0706e82
JB
1/*
2 * Copyright 2002-2004, Instant802 Networks, Inc.
3 * Copyright 2005, Devicescape Software, Inc.
f8079d43 4 * Copyright (C) 2016 Intel Deutschland GmbH
f0706e82
JB
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 */
f0706e82 10#include <linux/kernel.h>
8c046c8c 11#include <linux/bitops.h>
f0706e82
JB
12#include <linux/types.h>
13#include <linux/netdevice.h>
bc3b2d7f 14#include <linux/export.h>
8c046c8c 15#include <asm/unaligned.h>
f0706e82
JB
16
17#include <net/mac80211.h>
24487981 18#include "driver-ops.h"
2c8dccc7 19#include "key.h"
f0706e82
JB
20#include "tkip.h"
21#include "wep.h"
22
f0706e82
JB
23#define PHASE1_LOOP_COUNT 8
24
8c046c8c
HH
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 */
f0706e82
JB
29static const u16 tkip_sbox[256] =
30{
31 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
32 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
33 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
34 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
35 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
36 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
37 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
38 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
39 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
40 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
41 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
42 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
43 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
44 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
45 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
46 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
47 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
48 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
49 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
50 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
51 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
52 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
53 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
54 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
55 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
56 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
57 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
58 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
59 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
60 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
61 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
62 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
63};
64
8c046c8c 65static u16 tkipS(u16 val)
f0706e82 66{
8c046c8c 67 return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]);
f0706e82
JB
68}
69
c801242c
HH
70static u8 *write_tkip_iv(u8 *pos, u16 iv16)
71{
72 *pos++ = iv16 >> 8;
73 *pos++ = ((iv16 >> 8) | 0x20) & 0x7f;
74 *pos++ = iv16 & 0xFF;
75 return pos;
76}
77
8c046c8c
HH
78/*
79 * P1K := Phase1(TA, TK, TSC)
f0706e82
JB
80 * TA = transmitter address (48 bits)
81 * TK = dot11DefaultKeyValue or dot11KeyMappingValue (128 bits)
82 * TSC = TKIP sequence counter (48 bits, only 32 msb bits used)
83 * P1K: 80 bits
84 */
7c70537f
HH
85static void tkip_mixing_phase1(const u8 *tk, struct tkip_ctx *ctx,
86 const u8 *ta, u32 tsc_IV32)
f0706e82
JB
87{
88 int i, j;
82a57447 89 u16 *p1k = ctx->p1k;
f0706e82 90
8c046c8c
HH
91 p1k[0] = tsc_IV32 & 0xFFFF;
92 p1k[1] = tsc_IV32 >> 16;
93 p1k[2] = get_unaligned_le16(ta + 0);
94 p1k[3] = get_unaligned_le16(ta + 2);
95 p1k[4] = get_unaligned_le16(ta + 4);
f0706e82
JB
96
97 for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
98 j = 2 * (i & 1);
8c046c8c
HH
99 p1k[0] += tkipS(p1k[4] ^ get_unaligned_le16(tk + 0 + j));
100 p1k[1] += tkipS(p1k[0] ^ get_unaligned_le16(tk + 4 + j));
101 p1k[2] += tkipS(p1k[1] ^ get_unaligned_le16(tk + 8 + j));
102 p1k[3] += tkipS(p1k[2] ^ get_unaligned_le16(tk + 12 + j));
103 p1k[4] += tkipS(p1k[3] ^ get_unaligned_le16(tk + 0 + j)) + i;
f0706e82 104 }
ca99861d 105 ctx->state = TKIP_STATE_PHASE1_DONE;
523b02ea 106 ctx->p1k_iv32 = tsc_IV32;
f0706e82
JB
107}
108
7c70537f 109static void tkip_mixing_phase2(const u8 *tk, struct tkip_ctx *ctx,
3c838099 110 u16 tsc_IV16, u8 *rc4key)
f0706e82
JB
111{
112 u16 ppk[6];
3c838099 113 const u16 *p1k = ctx->p1k;
f0706e82
JB
114 int i;
115
116 ppk[0] = p1k[0];
117 ppk[1] = p1k[1];
118 ppk[2] = p1k[2];
119 ppk[3] = p1k[3];
120 ppk[4] = p1k[4];
121 ppk[5] = p1k[4] + tsc_IV16;
122
8c046c8c
HH
123 ppk[0] += tkipS(ppk[5] ^ get_unaligned_le16(tk + 0));
124 ppk[1] += tkipS(ppk[0] ^ get_unaligned_le16(tk + 2));
125 ppk[2] += tkipS(ppk[1] ^ get_unaligned_le16(tk + 4));
126 ppk[3] += tkipS(ppk[2] ^ get_unaligned_le16(tk + 6));
127 ppk[4] += tkipS(ppk[3] ^ get_unaligned_le16(tk + 8));
128 ppk[5] += tkipS(ppk[4] ^ get_unaligned_le16(tk + 10));
129 ppk[0] += ror16(ppk[5] ^ get_unaligned_le16(tk + 12), 1);
130 ppk[1] += ror16(ppk[0] ^ get_unaligned_le16(tk + 14), 1);
131 ppk[2] += ror16(ppk[1], 1);
132 ppk[3] += ror16(ppk[2], 1);
133 ppk[4] += ror16(ppk[3], 1);
134 ppk[5] += ror16(ppk[4], 1);
135
c801242c
HH
136 rc4key = write_tkip_iv(rc4key, tsc_IV16);
137 *rc4key++ = ((ppk[5] ^ get_unaligned_le16(tk)) >> 1) & 0xFF;
8c046c8c 138
8c046c8c
HH
139 for (i = 0; i < 6; i++)
140 put_unaligned_le16(ppk[i], rc4key + 2 * i);
f0706e82
JB
141}
142
f0706e82
JB
143/* Add TKIP IV and Ext. IV at @pos. @iv0, @iv1, and @iv2 are the first octets
144 * of the IV. Returns pointer to the octet following IVs (i.e., beginning of
145 * the packet payload). */
f8079d43 146u8 *ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key_conf *keyconf, u64 pn)
f0706e82 147{
f8079d43
EP
148 pos = write_tkip_iv(pos, TKIP_PN_TO_IV16(pn));
149 *pos++ = (keyconf->keyidx << 6) | (1 << 5) /* Ext IV */;
150 put_unaligned_le32(TKIP_PN_TO_IV32(pn), pos);
8c046c8c 151 return pos + 4;
f0706e82 152}
f8079d43 153EXPORT_SYMBOL_GPL(ieee80211_tkip_add_iv);
f0706e82 154
523b02ea
JB
155static void ieee80211_compute_tkip_p1k(struct ieee80211_key *key, u32 iv32)
156{
157 struct ieee80211_sub_if_data *sdata = key->sdata;
158 struct tkip_ctx *ctx = &key->u.tkip.tx;
159 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
160
161 lockdep_assert_held(&key->u.tkip.txlock);
162
163 /*
164 * Update the P1K when the IV32 is different from the value it
165 * had when we last computed it (or when not initialised yet).
166 * This might flip-flop back and forth if packets are processed
167 * out-of-order due to the different ACs, but then we have to
168 * just compute the P1K more often.
169 */
170 if (ctx->p1k_iv32 != iv32 || ctx->state == TKIP_STATE_NOT_INIT)
171 tkip_mixing_phase1(tk, ctx, sdata->vif.addr, iv32);
172}
173
42d98795
JB
174void ieee80211_get_tkip_p1k_iv(struct ieee80211_key_conf *keyconf,
175 u32 iv32, u16 *p1k)
5d2cdcd4
EG
176{
177 struct ieee80211_key *key = (struct ieee80211_key *)
178 container_of(keyconf, struct ieee80211_key, conf);
523b02ea 179 struct tkip_ctx *ctx = &key->u.tkip.tx;
523b02ea 180
03395003 181 spin_lock_bh(&key->u.tkip.txlock);
523b02ea
JB
182 ieee80211_compute_tkip_p1k(key, iv32);
183 memcpy(p1k, ctx->p1k, sizeof(ctx->p1k));
03395003 184 spin_unlock_bh(&key->u.tkip.txlock);
523b02ea 185}
42d98795 186EXPORT_SYMBOL(ieee80211_get_tkip_p1k_iv);
5d2cdcd4 187
8bca5d81 188void ieee80211_get_tkip_rx_p1k(struct ieee80211_key_conf *keyconf,
f359d3fe 189 const u8 *ta, u32 iv32, u16 *p1k)
8bca5d81
JB
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}
197EXPORT_SYMBOL(ieee80211_get_tkip_rx_p1k);
198
523b02ea
JB
199void 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);
523b02ea 210
655914ab 211 spin_lock(&key->u.tkip.txlock);
523b02ea
JB
212 ieee80211_compute_tkip_p1k(key, iv32);
213 tkip_mixing_phase2(tk, ctx, iv16, p2k);
655914ab 214 spin_unlock(&key->u.tkip.txlock);
5d2cdcd4 215}
523b02ea 216EXPORT_SYMBOL(ieee80211_get_tkip_p2k);
5d2cdcd4 217
813d7669
JB
218/*
219 * Encrypt packet payload with TKIP using @key. @pos is a pointer to the
f0706e82 220 * beginning of the buffer containing payload. This payload must include
813d7669
JB
221 * the IV/Ext.IV and space for (taildroom) four octets for ICV.
222 * @payload_len is the length of payload (_not_ including IV/ICV length).
223 * @ta is the transmitter addresses.
224 */
5f9f1812 225int ieee80211_tkip_encrypt_data(struct crypto_cipher *tfm,
3473187d 226 struct ieee80211_key *key,
523b02ea
JB
227 struct sk_buff *skb,
228 u8 *payload, size_t payload_len)
f0706e82
JB
229{
230 u8 rc4key[16];
7c70537f 231
523b02ea 232 ieee80211_get_tkip_p2k(&key->conf, skb, rc4key);
f0706e82 233
523b02ea
JB
234 return ieee80211_wep_encrypt_data(tfm, rc4key, 16,
235 payload, payload_len);
f0706e82
JB
236}
237
f0706e82
JB
238/* Decrypt packet payload with TKIP using @key. @pos is a pointer to the
239 * beginning of the buffer containing IEEE 802.11 header payload, i.e.,
240 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the
241 * length of payload, including IV, Ext. IV, MIC, ICV. */
5f9f1812 242int ieee80211_tkip_decrypt_data(struct crypto_cipher *tfm,
f0706e82
JB
243 struct ieee80211_key *key,
244 u8 *payload, size_t payload_len, u8 *ta,
9ae4fda3 245 u8 *ra, int only_iv, int queue,
50741ae0 246 u32 *out_iv32, u16 *out_iv16)
f0706e82
JB
247{
248 u32 iv32;
249 u32 iv16;
250 u8 rc4key[16], keyid, *pos = payload;
251 int res;
ffd7891d 252 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
f8079d43 253 struct tkip_ctx_rx *rx_ctx = &key->u.tkip.rx[queue];
f0706e82
JB
254
255 if (payload_len < 12)
256 return -1;
257
258 iv16 = (pos[0] << 8) | pos[2];
259 keyid = pos[3];
8c046c8c 260 iv32 = get_unaligned_le32(pos + 4);
f0706e82 261 pos += 8;
f0706e82
JB
262
263 if (!(keyid & (1 << 5)))
264 return TKIP_DECRYPT_NO_EXT_IV;
265
8f20fc24 266 if ((keyid >> 6) != key->conf.keyidx)
f0706e82
JB
267 return TKIP_DECRYPT_INVALID_KEYIDX;
268
0e44fd1d
JM
269 /* Reject replays if the received TSC is smaller than or equal to the
270 * last received value in a valid message, but with an exception for
271 * the case where a new key has been set and no valid frame using that
272 * key has yet received and the local RSC was initialized to 0. This
273 * exception allows the very first frame sent by the transmitter to be
274 * accepted even if that transmitter were to use TSC 0 (IEEE 802.11
275 * described TSC to be initialized to 1 whenever a new key is taken into
276 * use).
277 */
278 if (iv32 < rx_ctx->iv32 ||
279 (iv32 == rx_ctx->iv32 &&
280 (iv16 < rx_ctx->iv16 ||
281 (iv16 == rx_ctx->iv16 &&
282 (rx_ctx->iv32 || rx_ctx->iv16 ||
283 rx_ctx->ctx.state != TKIP_STATE_NOT_INIT)))))
f0706e82 284 return TKIP_DECRYPT_REPLAY;
f0706e82
JB
285
286 if (only_iv) {
287 res = TKIP_DECRYPT_OK;
f8079d43 288 rx_ctx->ctx.state = TKIP_STATE_PHASE1_HW_UPLOADED;
f0706e82
JB
289 goto done;
290 }
291
f8079d43
EP
292 if (rx_ctx->ctx.state == TKIP_STATE_NOT_INIT ||
293 rx_ctx->iv32 != iv32) {
f0706e82 294 /* IV16 wrapped around - perform TKIP phase 1 */
f8079d43 295 tkip_mixing_phase1(tk, &rx_ctx->ctx, ta, iv32);
ca99861d 296 }
297 if (key->local->ops->update_tkip_key &&
298 key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE &&
f8079d43 299 rx_ctx->ctx.state != TKIP_STATE_PHASE1_HW_UPLOADED) {
b3fbdcf4 300 struct ieee80211_sub_if_data *sdata = key->sdata;
ca99861d 301
b3fbdcf4
JB
302 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
303 sdata = container_of(key->sdata->bss,
304 struct ieee80211_sub_if_data, u.ap);
305 drv_update_tkip_key(key->local, sdata, &key->conf, key->sta,
f8079d43
EP
306 iv32, rx_ctx->ctx.p1k);
307 rx_ctx->ctx.state = TKIP_STATE_PHASE1_HW_UPLOADED;
f0706e82
JB
308 }
309
f8079d43 310 tkip_mixing_phase2(tk, &rx_ctx->ctx, iv16, rc4key);
f0706e82
JB
311
312 res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12);
313 done:
314 if (res == TKIP_DECRYPT_OK) {
50741ae0
JB
315 /*
316 * Record previously received IV, will be copied into the
317 * key information after MIC verification. It is possible
318 * that we don't catch replays of fragments but that's ok
319 * because the Michael MIC verication will then fail.
320 */
321 *out_iv32 = iv32;
322 *out_iv16 = iv16;
f0706e82
JB
323 }
324
325 return res;
326}