aboutsummaryrefslogtreecommitdiff
path: root/drivers/staging/wlan-ng/p80211wep.c
blob: c4fabadf5d74c081c70741ce793bc28392851829 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
/* src/p80211/p80211wep.c
*
* WEP encode/decode for P80211.
*
* Copyright (C) 2002 AbsoluteValue Systems, Inc.  All Rights Reserved.
* --------------------------------------------------------------------
*
* linux-wlan
*
*   The contents of this file are subject to the Mozilla Public
*   License Version 1.1 (the "License"); you may not use this file
*   except in compliance with the License. You may obtain a copy of
*   the License at http://www.mozilla.org/MPL/
*
*   Software distributed under the License is distributed on an "AS
*   IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
*   implied. See the License for the specific language governing
*   rights and limitations under the License.
*
*   Alternatively, the contents of this file may be used under the
*   terms of the GNU Public License version 2 (the "GPL"), in which
*   case the provisions of the GPL are applicable instead of the
*   above.  If you wish to allow the use of your version of this file
*   only under the terms of the GPL and not to allow others to use
*   your version of this file under the MPL, indicate your decision
*   by deleting the provisions above and replace them with the notice
*   and other provisions required by the GPL.  If you do not delete
*   the provisions above, a recipient may use your version of this
*   file under either the MPL or the GPL.
*
* --------------------------------------------------------------------
*
* Inquiries regarding the linux-wlan Open Source project can be
* made directly to:
*
* AbsoluteValue Systems Inc.
* info@linux-wlan.com
* http://www.linux-wlan.com
*
* --------------------------------------------------------------------
*
* Portions of the development of this software were funded by
* Intersil Corporation as part of PRISM(R) chipset product development.
*
* --------------------------------------------------------------------
*/

/*================================================================*/
/* System Includes */

#include <linux/netdevice.h>
#include <linux/wireless.h>
#include <linux/random.h>
#include <linux/kernel.h>

/* #define WEP_DEBUG	*/

#include "p80211hdr.h"
#include "p80211types.h"
#include "p80211msg.h"
#include "p80211conv.h"
#include "p80211netdev.h"

#define WEP_KEY(x)       (((x) & 0xC0) >> 6)

static const u32 wep_crc32_table[256] = {
	0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
	0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
	0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
	0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
	0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
	0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
	0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
	0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
	0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
	0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
	0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
	0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
	0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
	0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
	0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
	0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
	0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
	0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
	0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
	0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
	0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
	0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
	0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
	0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
	0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
	0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
	0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
	0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
	0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
	0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
	0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
	0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
	0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
	0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
	0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
	0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
	0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
	0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
	0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
	0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
	0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
	0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
	0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
	0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
	0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
	0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
	0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
	0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
	0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
	0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
	0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
	0x2d02ef8dL
};

/* keylen in bytes! */

int wep_change_key(wlandevice_t *wlandev, int keynum, u8 *key, int keylen)
{
	if (keylen < 0)
		return -1;
	if (keylen >= MAX_KEYLEN)
		return -1;
	if (key == NULL)
		return -1;
	if (keynum < 0)
		return -1;
	if (keynum >= NUM_WEPKEYS)
		return -1;

#ifdef WEP_DEBUG
	pr_debug("WEP key %d len %d = %*phC\n", keynum, keylen,
			  8, key);
#endif

	wlandev->wep_keylens[keynum] = keylen;
	memcpy(wlandev->wep_keys[keynum], key, keylen);

	return 0;
}

/*
  4-byte IV at start of buffer, 4-byte ICV at end of buffer.
  if successful, buf start is payload begin, length -= 8;
 */
int wep_decrypt(wlandevice_t *wlandev, u8 *buf, u32 len, int key_override,
		u8 *iv, u8 *icv)
{
	u32 i, j, k, crc, keylen;
	u8 s[256], key[64], c_crc[4];
	u8 keyidx;

	/* Needs to be at least 8 bytes of payload */
	if (len <= 0)
		return -1;

	/* initialize the first bytes of the key from the IV */
	key[0] = iv[0];
	key[1] = iv[1];
	key[2] = iv[2];
	keyidx = WEP_KEY(iv[3]);

	if (key_override >= 0)
		keyidx = key_override;

	if (keyidx >= NUM_WEPKEYS)
		return -2;

	keylen = wlandev->wep_keylens[keyidx];

	if (keylen == 0)
		return -3;

	/* copy the rest of the key over from the designated key */
	memcpy(key + 3, wlandev->wep_keys[keyidx], keylen);

	keylen += 3;		/* add in IV bytes */

#ifdef WEP_DEBUG
	pr_debug("D %d: %*ph (%d %d) %*phC\n", len, 3, key,
			  keyidx, keylen, 5, key + 3);
#endif

	/* set up the RC4 state */
	for (i = 0; i < 256; i++)
		s[i] = i;
	j = 0;
	for (i = 0; i < 256; i++) {
		j = (j + s[i] + key[i % keylen]) & 0xff;
		swap(i, j);
	}

	/* Apply the RC4 to the data, update the CRC32 */
	crc = ~0;
	i = j = 0;
	for (k = 0; k < len; k++) {
		i = (i + 1) & 0xff;
		j = (j + s[i]) & 0xff;
		swap(i, j);
		buf[k] ^= s[(s[i] + s[j]) & 0xff];
		crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8);
	}
	crc = ~crc;

	/* now let's check the crc */
	c_crc[0] = crc;
	c_crc[1] = crc >> 8;
	c_crc[2] = crc >> 16;
	c_crc[3] = crc >> 24;

	for (k = 0; k < 4; k++) {
		i = (i + 1) & 0xff;
		j = (j + s[i]) & 0xff;
		swap(i, j);
		if ((c_crc[k] ^ s[(s[i] + s[j]) & 0xff]) != icv[k])
			return -(4 | (k << 4));	/* ICV mismatch */
	}

	return 0;
}

/* encrypts in-place. */
int wep_encrypt(wlandevice_t *wlandev, u8 *buf, u8 *dst, u32 len, int keynum,
		u8 *iv, u8 *icv)
{
	u32 i, j, k, crc, keylen;
	u8 s[256], key[64];

	/* no point in WEPping an empty frame */
	if (len <= 0)
		return -1;

	/* we need to have a real key.. */
	if (keynum >= NUM_WEPKEYS)
		return -2;
	keylen = wlandev->wep_keylens[keynum];
	if (keylen <= 0)
		return -3;

	/* use a random IV.  And skip known weak ones. */
	get_random_bytes(iv, 3);
	while ((iv[1] == 0xff) && (iv[0] >= 3) && (iv[0] < keylen))
		get_random_bytes(iv, 3);

	iv[3] = (keynum & 0x03) << 6;

	key[0] = iv[0];
	key[1] = iv[1];
	key[2] = iv[2];

	/* copy the rest of the key over from the designated key */
	memcpy(key + 3, wlandev->wep_keys[keynum], keylen);

	keylen += 3;		/* add in IV bytes */

#ifdef WEP_DEBUG
	pr_debug("E %d (%d/%d %d) %*ph %*phC\n", len,
			  iv[3], keynum, keylen, 3, key, 5, key + 3);
#endif

	/* set up the RC4 state */
	for (i = 0; i < 256; i++)
		s[i] = i;
	j = 0;
	for (i = 0; i < 256; i++) {
		j = (j + s[i] + key[i % keylen]) & 0xff;
		swap(i, j);
	}

	/* Update CRC32 then apply RC4 to the data */
	crc = ~0;
	i = j = 0;
	for (k = 0; k < len; k++) {
		crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8);
		i = (i + 1) & 0xff;
		j = (j + s[i]) & 0xff;
		swap(i, j);
		dst[k] = buf[k] ^ s[(s[i] + s[j]) & 0xff];
	}
	crc = ~crc;

	/* now let's encrypt the crc */
	icv[0] = crc;
	icv[1] = crc >> 8;
	icv[2] = crc >> 16;
	icv[3] = crc >> 24;

	for (k = 0; k < 4; k++) {
		i = (i + 1) & 0xff;
		j = (j + s[i]) & 0xff;
		swap(i, j);
		icv[k] ^= s[(s[i] + s[j]) & 0xff];
	}

	return 0;
}