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 /* #define WEP_DEBUG */
57
58 #include "p80211hdr.h"
59 #include "p80211types.h"
60 #include "p80211msg.h"
61 #include "p80211conv.h"
62 #include "p80211netdev.h"
63
64 #define WEP_KEY(x) (((x) & 0xC0) >> 6)
65
66 static const u32 wep_crc32_table[256] = {
67 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
68 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
69 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
70 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
71 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
72 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
73 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
74 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
75 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
76 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
77 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
78 0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
79 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
80 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
81 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
82 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
83 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
84 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
85 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
86 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
87 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
88 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
89 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
90 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
91 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
92 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
93 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
94 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
95 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
96 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
97 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
98 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
99 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
100 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
101 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
102 0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
103 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
104 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
105 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
106 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
107 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
108 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
109 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
110 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
111 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
112 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
113 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
114 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
115 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
116 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
117 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
118 0x2d02ef8dL
119 };
120
121 /* keylen in bytes! */
122
wep_change_key(wlandevice_t * wlandev,int keynum,u8 * key,int keylen)123 int wep_change_key(wlandevice_t *wlandev, int keynum, u8 *key, int keylen)
124 {
125 if (keylen < 0)
126 return -1;
127 if (keylen >= MAX_KEYLEN)
128 return -1;
129 if (key == NULL)
130 return -1;
131 if (keynum < 0)
132 return -1;
133 if (keynum >= NUM_WEPKEYS)
134 return -1;
135
136 #ifdef WEP_DEBUG
137 printk(KERN_DEBUG "WEP key %d len %d = %*phC\n", keynum, keylen,
138 8, key);
139 #endif
140
141 wlandev->wep_keylens[keynum] = keylen;
142 memcpy(wlandev->wep_keys[keynum], key, keylen);
143
144 return 0;
145 }
146
147 /*
148 4-byte IV at start of buffer, 4-byte ICV at end of buffer.
149 if successful, buf start is payload begin, length -= 8;
150 */
wep_decrypt(wlandevice_t * wlandev,u8 * buf,u32 len,int key_override,u8 * iv,u8 * icv)151 int wep_decrypt(wlandevice_t *wlandev, u8 *buf, u32 len, int key_override,
152 u8 *iv, u8 *icv)
153 {
154 u32 i, j, k, crc, keylen;
155 u8 s[256], key[64], c_crc[4];
156 u8 keyidx;
157
158 /* Needs to be at least 8 bytes of payload */
159 if (len <= 0)
160 return -1;
161
162 /* initialize the first bytes of the key from the IV */
163 key[0] = iv[0];
164 key[1] = iv[1];
165 key[2] = iv[2];
166 keyidx = WEP_KEY(iv[3]);
167
168 if (key_override >= 0)
169 keyidx = key_override;
170
171 if (keyidx >= NUM_WEPKEYS)
172 return -2;
173
174 keylen = wlandev->wep_keylens[keyidx];
175
176 if (keylen == 0)
177 return -3;
178
179 /* copy the rest of the key over from the designated key */
180 memcpy(key + 3, wlandev->wep_keys[keyidx], keylen);
181
182 keylen += 3; /* add in IV bytes */
183
184 #ifdef WEP_DEBUG
185 printk(KERN_DEBUG "D %d: %*ph (%d %d) %*phC\n", len, 3, key,
186 keyidx, keylen, 5, key + 3);
187 #endif
188
189 /* set up the RC4 state */
190 for (i = 0; i < 256; i++)
191 s[i] = i;
192 j = 0;
193 for (i = 0; i < 256; i++) {
194 j = (j + s[i] + key[i % keylen]) & 0xff;
195 swap(i, j);
196 }
197
198 /* Apply the RC4 to the data, update the CRC32 */
199 crc = ~0;
200 i = j = 0;
201 for (k = 0; k < len; k++) {
202 i = (i + 1) & 0xff;
203 j = (j + s[i]) & 0xff;
204 swap(i, j);
205 buf[k] ^= s[(s[i] + s[j]) & 0xff];
206 crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8);
207 }
208 crc = ~crc;
209
210 /* now let's check the crc */
211 c_crc[0] = crc;
212 c_crc[1] = crc >> 8;
213 c_crc[2] = crc >> 16;
214 c_crc[3] = crc >> 24;
215
216 for (k = 0; k < 4; k++) {
217 i = (i + 1) & 0xff;
218 j = (j + s[i]) & 0xff;
219 swap(i, j);
220 if ((c_crc[k] ^ s[(s[i] + s[j]) & 0xff]) != icv[k])
221 return -(4 | (k << 4)); /* ICV mismatch */
222 }
223
224 return 0;
225 }
226
227 /* encrypts in-place. */
wep_encrypt(wlandevice_t * wlandev,u8 * buf,u8 * dst,u32 len,int keynum,u8 * iv,u8 * icv)228 int wep_encrypt(wlandevice_t *wlandev, u8 *buf, u8 *dst, u32 len, int keynum,
229 u8 *iv, u8 *icv)
230 {
231 u32 i, j, k, crc, keylen;
232 u8 s[256], key[64];
233
234 /* no point in WEPping an empty frame */
235 if (len <= 0)
236 return -1;
237
238 /* we need to have a real key.. */
239 if (keynum >= NUM_WEPKEYS)
240 return -2;
241 keylen = wlandev->wep_keylens[keynum];
242 if (keylen <= 0)
243 return -3;
244
245 /* use a random IV. And skip known weak ones. */
246 get_random_bytes(iv, 3);
247 while ((iv[1] == 0xff) && (iv[0] >= 3) && (iv[0] < keylen))
248 get_random_bytes(iv, 3);
249
250 iv[3] = (keynum & 0x03) << 6;
251
252 key[0] = iv[0];
253 key[1] = iv[1];
254 key[2] = iv[2];
255
256 /* copy the rest of the key over from the designated key */
257 memcpy(key + 3, wlandev->wep_keys[keynum], keylen);
258
259 keylen += 3; /* add in IV bytes */
260
261 #ifdef WEP_DEBUG
262 printk(KERN_DEBUG "E %d (%d/%d %d) %*ph %*phC\n", len,
263 iv[3], keynum, keylen, 3, key, 5, key + 3);
264 #endif
265
266 /* set up the RC4 state */
267 for (i = 0; i < 256; i++)
268 s[i] = i;
269 j = 0;
270 for (i = 0; i < 256; i++) {
271 j = (j + s[i] + key[i % keylen]) & 0xff;
272 swap(i, j);
273 }
274
275 /* Update CRC32 then apply RC4 to the data */
276 crc = ~0;
277 i = j = 0;
278 for (k = 0; k < len; k++) {
279 crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8);
280 i = (i + 1) & 0xff;
281 j = (j + s[i]) & 0xff;
282 swap(i, j);
283 dst[k] = buf[k] ^ s[(s[i] + s[j]) & 0xff];
284 }
285 crc = ~crc;
286
287 /* now let's encrypt the crc */
288 icv[0] = crc;
289 icv[1] = crc >> 8;
290 icv[2] = crc >> 16;
291 icv[3] = crc >> 24;
292
293 for (k = 0; k < 4; k++) {
294 i = (i + 1) & 0xff;
295 j = (j + s[i]) & 0xff;
296 swap(i, j);
297 icv[k] ^= s[(s[i] + s[j]) & 0xff];
298 }
299
300 return 0;
301 }
302