1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2002-2004, Instant802 Networks, Inc.
4 * Copyright 2005, Devicescape Software, Inc.
5 * Copyright (C) 2016 Intel Deutschland GmbH
6 */
7 #include <linux/kernel.h>
8 #include <linux/bitops.h>
9 #include <linux/types.h>
10 #include <linux/netdevice.h>
11 #include <linux/export.h>
12 #include <linux/unaligned.h>
13
14 #include <net/mac80211.h>
15 #include "driver-ops.h"
16 #include "key.h"
17 #include "tkip.h"
18 #include "wep.h"
19
20 #define PHASE1_LOOP_COUNT 8
21
22 /*
23 * 2-byte by 2-byte subset of the full AES S-box table; second part of this
24 * table is identical to first part but byte-swapped
25 */
26 static const u16 tkip_sbox[256] =
27 {
28 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
29 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
30 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
31 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
32 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
33 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
34 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
35 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
36 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
37 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
38 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
39 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
40 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
41 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
42 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
43 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
44 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
45 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
46 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
47 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
48 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
49 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
50 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
51 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
52 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
53 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
54 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
55 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
56 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
57 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
58 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
59 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
60 };
61
tkipS(u16 val)62 static u16 tkipS(u16 val)
63 {
64 return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]);
65 }
66
write_tkip_iv(u8 * pos,u16 iv16)67 static u8 *write_tkip_iv(u8 *pos, u16 iv16)
68 {
69 *pos++ = iv16 >> 8;
70 *pos++ = ((iv16 >> 8) | 0x20) & 0x7f;
71 *pos++ = iv16 & 0xFF;
72 return pos;
73 }
74
75 /*
76 * P1K := Phase1(TA, TK, TSC)
77 * TA = transmitter address (48 bits)
78 * TK = dot11DefaultKeyValue or dot11KeyMappingValue (128 bits)
79 * TSC = TKIP sequence counter (48 bits, only 32 msb bits used)
80 * P1K: 80 bits
81 */
tkip_mixing_phase1(const u8 * tk,struct tkip_ctx * ctx,const u8 * ta,u32 tsc_IV32)82 static void tkip_mixing_phase1(const u8 *tk, struct tkip_ctx *ctx,
83 const u8 *ta, u32 tsc_IV32)
84 {
85 int i, j;
86 u16 *p1k = ctx->p1k;
87
88 p1k[0] = tsc_IV32 & 0xFFFF;
89 p1k[1] = tsc_IV32 >> 16;
90 p1k[2] = get_unaligned_le16(ta + 0);
91 p1k[3] = get_unaligned_le16(ta + 2);
92 p1k[4] = get_unaligned_le16(ta + 4);
93
94 for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
95 j = 2 * (i & 1);
96 p1k[0] += tkipS(p1k[4] ^ get_unaligned_le16(tk + 0 + j));
97 p1k[1] += tkipS(p1k[0] ^ get_unaligned_le16(tk + 4 + j));
98 p1k[2] += tkipS(p1k[1] ^ get_unaligned_le16(tk + 8 + j));
99 p1k[3] += tkipS(p1k[2] ^ get_unaligned_le16(tk + 12 + j));
100 p1k[4] += tkipS(p1k[3] ^ get_unaligned_le16(tk + 0 + j)) + i;
101 }
102 ctx->state = TKIP_STATE_PHASE1_DONE;
103 ctx->p1k_iv32 = tsc_IV32;
104 }
105
tkip_mixing_phase2(const u8 * tk,struct tkip_ctx * ctx,u16 tsc_IV16,u8 * rc4key)106 static void tkip_mixing_phase2(const u8 *tk, struct tkip_ctx *ctx,
107 u16 tsc_IV16, u8 *rc4key)
108 {
109 u16 ppk[6];
110 const u16 *p1k = ctx->p1k;
111 int i;
112
113 ppk[0] = p1k[0];
114 ppk[1] = p1k[1];
115 ppk[2] = p1k[2];
116 ppk[3] = p1k[3];
117 ppk[4] = p1k[4];
118 ppk[5] = p1k[4] + tsc_IV16;
119
120 ppk[0] += tkipS(ppk[5] ^ get_unaligned_le16(tk + 0));
121 ppk[1] += tkipS(ppk[0] ^ get_unaligned_le16(tk + 2));
122 ppk[2] += tkipS(ppk[1] ^ get_unaligned_le16(tk + 4));
123 ppk[3] += tkipS(ppk[2] ^ get_unaligned_le16(tk + 6));
124 ppk[4] += tkipS(ppk[3] ^ get_unaligned_le16(tk + 8));
125 ppk[5] += tkipS(ppk[4] ^ get_unaligned_le16(tk + 10));
126 ppk[0] += ror16(ppk[5] ^ get_unaligned_le16(tk + 12), 1);
127 ppk[1] += ror16(ppk[0] ^ get_unaligned_le16(tk + 14), 1);
128 ppk[2] += ror16(ppk[1], 1);
129 ppk[3] += ror16(ppk[2], 1);
130 ppk[4] += ror16(ppk[3], 1);
131 ppk[5] += ror16(ppk[4], 1);
132
133 rc4key = write_tkip_iv(rc4key, tsc_IV16);
134 *rc4key++ = ((ppk[5] ^ get_unaligned_le16(tk)) >> 1) & 0xFF;
135
136 for (i = 0; i < 6; i++)
137 put_unaligned_le16(ppk[i], rc4key + 2 * i);
138 }
139
140 /* Add TKIP IV and Ext. IV at @pos. @iv0, @iv1, and @iv2 are the first octets
141 * of the IV. Returns pointer to the octet following IVs (i.e., beginning of
142 * the packet payload). */
ieee80211_tkip_add_iv(u8 * pos,struct ieee80211_key_conf * keyconf,u64 pn)143 u8 *ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key_conf *keyconf, u64 pn)
144 {
145 pos = write_tkip_iv(pos, TKIP_PN_TO_IV16(pn));
146 *pos++ = (keyconf->keyidx << 6) | (1 << 5) /* Ext IV */;
147 put_unaligned_le32(TKIP_PN_TO_IV32(pn), pos);
148 return pos + 4;
149 }
150 EXPORT_SYMBOL_GPL(ieee80211_tkip_add_iv);
151
ieee80211_compute_tkip_p1k(struct ieee80211_key * key,u32 iv32)152 static void ieee80211_compute_tkip_p1k(struct ieee80211_key *key, u32 iv32)
153 {
154 struct ieee80211_sub_if_data *sdata = key->sdata;
155 struct tkip_ctx *ctx = &key->u.tkip.tx;
156 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
157
158 lockdep_assert_held(&key->u.tkip.txlock);
159
160 /*
161 * Update the P1K when the IV32 is different from the value it
162 * had when we last computed it (or when not initialised yet).
163 * This might flip-flop back and forth if packets are processed
164 * out-of-order due to the different ACs, but then we have to
165 * just compute the P1K more often.
166 */
167 if (ctx->p1k_iv32 != iv32 || ctx->state == TKIP_STATE_NOT_INIT)
168 tkip_mixing_phase1(tk, ctx, sdata->vif.addr, iv32);
169 }
170
ieee80211_get_tkip_p1k_iv(struct ieee80211_key_conf * keyconf,u32 iv32,u16 * p1k)171 void ieee80211_get_tkip_p1k_iv(struct ieee80211_key_conf *keyconf,
172 u32 iv32, u16 *p1k)
173 {
174 struct ieee80211_key *key = (struct ieee80211_key *)
175 container_of(keyconf, struct ieee80211_key, conf);
176 struct tkip_ctx *ctx = &key->u.tkip.tx;
177
178 spin_lock_bh(&key->u.tkip.txlock);
179 ieee80211_compute_tkip_p1k(key, iv32);
180 memcpy(p1k, ctx->p1k, sizeof(ctx->p1k));
181 spin_unlock_bh(&key->u.tkip.txlock);
182 }
183 EXPORT_SYMBOL(ieee80211_get_tkip_p1k_iv);
184
ieee80211_get_tkip_rx_p1k(struct ieee80211_key_conf * keyconf,const u8 * ta,u32 iv32,u16 * p1k)185 void ieee80211_get_tkip_rx_p1k(struct ieee80211_key_conf *keyconf,
186 const u8 *ta, u32 iv32, u16 *p1k)
187 {
188 const u8 *tk = &keyconf->key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
189 struct tkip_ctx ctx;
190
191 tkip_mixing_phase1(tk, &ctx, ta, iv32);
192 memcpy(p1k, ctx.p1k, sizeof(ctx.p1k));
193 }
194 EXPORT_SYMBOL(ieee80211_get_tkip_rx_p1k);
195
ieee80211_get_tkip_p2k(struct ieee80211_key_conf * keyconf,struct sk_buff * skb,u8 * p2k)196 void ieee80211_get_tkip_p2k(struct ieee80211_key_conf *keyconf,
197 struct sk_buff *skb, u8 *p2k)
198 {
199 struct ieee80211_key *key = (struct ieee80211_key *)
200 container_of(keyconf, struct ieee80211_key, conf);
201 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
202 struct tkip_ctx *ctx = &key->u.tkip.tx;
203 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
204 const u8 *data = (u8 *)hdr + ieee80211_hdrlen(hdr->frame_control);
205 u32 iv32 = get_unaligned_le32(&data[4]);
206 u16 iv16 = data[2] | (data[0] << 8);
207
208 spin_lock(&key->u.tkip.txlock);
209 ieee80211_compute_tkip_p1k(key, iv32);
210 tkip_mixing_phase2(tk, ctx, iv16, p2k);
211 spin_unlock(&key->u.tkip.txlock);
212 }
213 EXPORT_SYMBOL(ieee80211_get_tkip_p2k);
214
215 /*
216 * Encrypt packet payload with TKIP using @key. @pos is a pointer to the
217 * beginning of the buffer containing payload. This payload must include
218 * the IV/Ext.IV and space for (taildroom) four octets for ICV.
219 * @payload_len is the length of payload (_not_ including IV/ICV length).
220 * @ta is the transmitter addresses.
221 */
ieee80211_tkip_encrypt_data(struct arc4_ctx * ctx,struct ieee80211_key * key,struct sk_buff * skb,u8 * payload,size_t payload_len)222 int ieee80211_tkip_encrypt_data(struct arc4_ctx *ctx,
223 struct ieee80211_key *key,
224 struct sk_buff *skb,
225 u8 *payload, size_t payload_len)
226 {
227 u8 rc4key[16];
228
229 ieee80211_get_tkip_p2k(&key->conf, skb, rc4key);
230
231 return ieee80211_wep_encrypt_data(ctx, rc4key, 16,
232 payload, payload_len);
233 }
234
235 /* Decrypt packet payload with TKIP using @key. @pos is a pointer to the
236 * beginning of the buffer containing IEEE 802.11 header payload, i.e.,
237 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the
238 * length of payload, including IV, Ext. IV, MIC, ICV. */
ieee80211_tkip_decrypt_data(struct arc4_ctx * ctx,struct ieee80211_key * key,u8 * payload,size_t payload_len,u8 * ta,u8 * ra,int only_iv,int queue,u32 * out_iv32,u16 * out_iv16)239 int ieee80211_tkip_decrypt_data(struct arc4_ctx *ctx,
240 struct ieee80211_key *key,
241 u8 *payload, size_t payload_len, u8 *ta,
242 u8 *ra, int only_iv, int queue,
243 u32 *out_iv32, u16 *out_iv16)
244 {
245 u32 iv32;
246 u32 iv16;
247 u8 rc4key[16], keyid, *pos = payload;
248 int res;
249 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
250 struct tkip_ctx_rx *rx_ctx = &key->u.tkip.rx[queue];
251
252 if (payload_len < 12)
253 return -1;
254
255 iv16 = (pos[0] << 8) | pos[2];
256 keyid = pos[3];
257 iv32 = get_unaligned_le32(pos + 4);
258 pos += 8;
259
260 if (!(keyid & (1 << 5)))
261 return TKIP_DECRYPT_NO_EXT_IV;
262
263 if ((keyid >> 6) != key->conf.keyidx)
264 return TKIP_DECRYPT_INVALID_KEYIDX;
265
266 /* Reject replays if the received TSC is smaller than or equal to the
267 * last received value in a valid message, but with an exception for
268 * the case where a new key has been set and no valid frame using that
269 * key has yet received and the local RSC was initialized to 0. This
270 * exception allows the very first frame sent by the transmitter to be
271 * accepted even if that transmitter were to use TSC 0 (IEEE 802.11
272 * described TSC to be initialized to 1 whenever a new key is taken into
273 * use).
274 */
275 if (iv32 < rx_ctx->iv32 ||
276 (iv32 == rx_ctx->iv32 &&
277 (iv16 < rx_ctx->iv16 ||
278 (iv16 == rx_ctx->iv16 &&
279 (rx_ctx->iv32 || rx_ctx->iv16 ||
280 rx_ctx->ctx.state != TKIP_STATE_NOT_INIT)))))
281 return TKIP_DECRYPT_REPLAY;
282
283 if (only_iv) {
284 res = TKIP_DECRYPT_OK;
285 rx_ctx->ctx.state = TKIP_STATE_PHASE1_HW_UPLOADED;
286 goto done;
287 }
288
289 if (rx_ctx->ctx.state == TKIP_STATE_NOT_INIT ||
290 rx_ctx->iv32 != iv32) {
291 /* IV16 wrapped around - perform TKIP phase 1 */
292 tkip_mixing_phase1(tk, &rx_ctx->ctx, ta, iv32);
293 }
294 if (key->local->ops->update_tkip_key &&
295 key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE &&
296 rx_ctx->ctx.state != TKIP_STATE_PHASE1_HW_UPLOADED) {
297 struct ieee80211_sub_if_data *sdata = key->sdata;
298
299 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
300 sdata = container_of(key->sdata->bss,
301 struct ieee80211_sub_if_data, u.ap);
302 drv_update_tkip_key(key->local, sdata, &key->conf, key->sta,
303 iv32, rx_ctx->ctx.p1k);
304 rx_ctx->ctx.state = TKIP_STATE_PHASE1_HW_UPLOADED;
305 }
306
307 tkip_mixing_phase2(tk, &rx_ctx->ctx, iv16, rc4key);
308
309 res = ieee80211_wep_decrypt_data(ctx, rc4key, 16, pos, payload_len - 12);
310 done:
311 if (res == TKIP_DECRYPT_OK) {
312 /*
313 * Record previously received IV, will be copied into the
314 * key information after MIC verification. It is possible
315 * that we don't catch replays of fragments but that's ok
316 * because the Michael MIC verication will then fail.
317 */
318 *out_iv32 = iv32;
319 *out_iv16 = iv16;
320 }
321
322 return res;
323 }
324