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 <asm/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 */
26static 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
62static u16 tkipS(u16 val)
63{
64	return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]);
65}
66
67static 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 */
82static 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
106static 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). */
143u8 *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}
150EXPORT_SYMBOL_GPL(ieee80211_tkip_add_iv);
151
152static 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
171void 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}
183EXPORT_SYMBOL(ieee80211_get_tkip_p1k_iv);
184
185void 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}
194EXPORT_SYMBOL(ieee80211_get_tkip_rx_p1k);
195
196void 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}
213EXPORT_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 */
222int 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.  */
239int 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