1 /* src/p80211/p80211wep.c
2 *
3 * WEP encode/decode for P80211.
4 *
5 * Copyright (C) 2002 AbsoluteValue Systems, Inc. All Rights Reserved.
6 * --------------------------------------------------------------------
7 *
8 * linux-wlan
9 *
10 * The contents of this file are subject to the Mozilla Public
11 * License Version 1.1 (the "License"); you may not use this file
12 * except in compliance with the License. You may obtain a copy of
13 * the License at http://www.mozilla.org/MPL/
14 *
15 * Software distributed under the License is distributed on an "AS
16 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
17 * implied. See the License for the specific language governing
18 * rights and limitations under the License.
19 *
20 * Alternatively, the contents of this file may be used under the
21 * terms of the GNU Public License version 2 (the "GPL"), in which
22 * case the provisions of the GPL are applicable instead of the
23 * above. If you wish to allow the use of your version of this file
24 * only under the terms of the GPL and not to allow others to use
25 * your version of this file under the MPL, indicate your decision
26 * by deleting the provisions above and replace them with the notice
27 * and other provisions required by the GPL. If you do not delete
28 * the provisions above, a recipient may use your version of this
29 * file under either the MPL or the GPL.
30 *
31 * --------------------------------------------------------------------
32 *
33 * Inquiries regarding the linux-wlan Open Source project can be
34 * made directly to:
35 *
36 * AbsoluteValue Systems Inc.
37 * info@linux-wlan.com
38 * http://www.linux-wlan.com
39 *
40 * --------------------------------------------------------------------
41 *
42 * Portions of the development of this software were funded by
43 * Intersil Corporation as part of PRISM(R) chipset product development.
44 *
45 * --------------------------------------------------------------------
46 */
47
48 /*================================================================*/
49 /* System Includes */
50
51 #include <linux/netdevice.h>
52 #include <linux/wireless.h>
53 #include <linux/random.h>
54 #include <linux/kernel.h>
55
56
57 #include "p80211hdr.h"
58 #include "p80211types.h"
59 #include "p80211msg.h"
60 #include "p80211conv.h"
61 #include "p80211netdev.h"
62
63 #define WEP_KEY(x) (((x) & 0xC0) >> 6)
64
65 static const u32 wep_crc32_table[256] = {
66 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
67 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
68 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
69 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
70 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
71 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
72 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
73 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
74 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
75 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
76 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
77 0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
78 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
79 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
80 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
81 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
82 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
83 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
84 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
85 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
86 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
87 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
88 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
89 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
90 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
91 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
92 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
93 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
94 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
95 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
96 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
97 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
98 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
99 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
100 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
101 0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
102 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
103 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
104 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
105 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
106 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
107 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
108 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
109 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
110 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
111 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
112 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
113 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
114 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
115 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
116 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
117 0x2d02ef8dL
118 };
119
120 /* keylen in bytes! */
121
wep_change_key(wlandevice_t * wlandev,int keynum,u8 * key,int keylen)122 int wep_change_key(wlandevice_t *wlandev, int keynum, u8 *key, int keylen)
123 {
124 if (keylen < 0)
125 return -1;
126 if (keylen >= MAX_KEYLEN)
127 return -1;
128 if (key == NULL)
129 return -1;
130 if (keynum < 0)
131 return -1;
132 if (keynum >= NUM_WEPKEYS)
133 return -1;
134
135
136 wlandev->wep_keylens[keynum] = keylen;
137 memcpy(wlandev->wep_keys[keynum], key, keylen);
138
139 return 0;
140 }
141
142 /*
143 4-byte IV at start of buffer, 4-byte ICV at end of buffer.
144 if successful, buf start is payload begin, length -= 8;
145 */
wep_decrypt(wlandevice_t * wlandev,u8 * buf,u32 len,int key_override,u8 * iv,u8 * icv)146 int wep_decrypt(wlandevice_t *wlandev, u8 *buf, u32 len, int key_override,
147 u8 *iv, u8 *icv)
148 {
149 u32 i, j, k, crc, keylen;
150 u8 s[256], key[64], c_crc[4];
151 u8 keyidx;
152
153 /* Needs to be at least 8 bytes of payload */
154 if (len <= 0)
155 return -1;
156
157 /* initialize the first bytes of the key from the IV */
158 key[0] = iv[0];
159 key[1] = iv[1];
160 key[2] = iv[2];
161 keyidx = WEP_KEY(iv[3]);
162
163 if (key_override >= 0)
164 keyidx = key_override;
165
166 if (keyidx >= NUM_WEPKEYS)
167 return -2;
168
169 keylen = wlandev->wep_keylens[keyidx];
170
171 if (keylen == 0)
172 return -3;
173
174 /* copy the rest of the key over from the designated key */
175 memcpy(key + 3, wlandev->wep_keys[keyidx], keylen);
176
177 keylen += 3; /* add in IV bytes */
178
179
180 /* set up the RC4 state */
181 for (i = 0; i < 256; i++)
182 s[i] = i;
183 j = 0;
184 for (i = 0; i < 256; i++) {
185 j = (j + s[i] + key[i % keylen]) & 0xff;
186 swap(i, j);
187 }
188
189 /* Apply the RC4 to the data, update the CRC32 */
190 crc = ~0;
191 i = j = 0;
192 for (k = 0; k < len; k++) {
193 i = (i + 1) & 0xff;
194 j = (j + s[i]) & 0xff;
195 swap(i, j);
196 buf[k] ^= s[(s[i] + s[j]) & 0xff];
197 crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8);
198 }
199 crc = ~crc;
200
201 /* now let's check the crc */
202 c_crc[0] = crc;
203 c_crc[1] = crc >> 8;
204 c_crc[2] = crc >> 16;
205 c_crc[3] = crc >> 24;
206
207 for (k = 0; k < 4; k++) {
208 i = (i + 1) & 0xff;
209 j = (j + s[i]) & 0xff;
210 swap(i, j);
211 if ((c_crc[k] ^ s[(s[i] + s[j]) & 0xff]) != icv[k])
212 return -(4 | (k << 4)); /* ICV mismatch */
213 }
214
215 return 0;
216 }
217
218 /* encrypts in-place. */
wep_encrypt(wlandevice_t * wlandev,u8 * buf,u8 * dst,u32 len,int keynum,u8 * iv,u8 * icv)219 int wep_encrypt(wlandevice_t *wlandev, u8 *buf, u8 *dst, u32 len, int keynum,
220 u8 *iv, u8 *icv)
221 {
222 u32 i, j, k, crc, keylen;
223 u8 s[256], key[64];
224
225 /* no point in WEPping an empty frame */
226 if (len <= 0)
227 return -1;
228
229 /* we need to have a real key.. */
230 if (keynum >= NUM_WEPKEYS)
231 return -2;
232 keylen = wlandev->wep_keylens[keynum];
233 if (keylen <= 0)
234 return -3;
235
236 /* use a random IV. And skip known weak ones. */
237 get_random_bytes(iv, 3);
238 while ((iv[1] == 0xff) && (iv[0] >= 3) && (iv[0] < keylen))
239 get_random_bytes(iv, 3);
240
241 iv[3] = (keynum & 0x03) << 6;
242
243 key[0] = iv[0];
244 key[1] = iv[1];
245 key[2] = iv[2];
246
247 /* copy the rest of the key over from the designated key */
248 memcpy(key + 3, wlandev->wep_keys[keynum], keylen);
249
250 keylen += 3; /* add in IV bytes */
251
252 /* set up the RC4 state */
253 for (i = 0; i < 256; i++)
254 s[i] = i;
255 j = 0;
256 for (i = 0; i < 256; i++) {
257 j = (j + s[i] + key[i % keylen]) & 0xff;
258 swap(i, j);
259 }
260
261 /* Update CRC32 then apply RC4 to the data */
262 crc = ~0;
263 i = j = 0;
264 for (k = 0; k < len; k++) {
265 crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8);
266 i = (i + 1) & 0xff;
267 j = (j + s[i]) & 0xff;
268 swap(i, j);
269 dst[k] = buf[k] ^ s[(s[i] + s[j]) & 0xff];
270 }
271 crc = ~crc;
272
273 /* now let's encrypt the crc */
274 icv[0] = crc;
275 icv[1] = crc >> 8;
276 icv[2] = crc >> 16;
277 icv[3] = crc >> 24;
278
279 for (k = 0; k < 4; k++) {
280 i = (i + 1) & 0xff;
281 j = (j + s[i]) & 0xff;
282 swap(i, j);
283 icv[k] ^= s[(s[i] + s[j]) & 0xff];
284 }
285
286 return 0;
287 }
288