ia64/linux-2.6.18-xen.hg

view net/ieee80211/ieee80211_crypt_wep.c @ 673:3161879fdf22

[IA64] xencomm: support XENMEM_add_to_physmap and XENMEM_remove_from_phsymap

support XENMEM_add_to_physmap and XENMEM_remove_from_phsymap.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
author Isaku Yamahata <yamahata@valinux.co.jp>
date Tue Sep 16 21:26:15 2008 +0900 (2008-09-16)
parents 831230e53067
children
line source
1 /*
2 * Host AP crypt: host-based WEP encryption implementation for Host AP driver
3 *
4 * Copyright (c) 2002-2004, Jouni Malinen <jkmaline@cc.hut.fi>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation. See README and COPYING for
9 * more details.
10 */
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/slab.h>
15 #include <linux/random.h>
16 #include <linux/skbuff.h>
17 #include <asm/string.h>
19 #include <net/ieee80211.h>
21 #include <linux/crypto.h>
22 #include <asm/scatterlist.h>
23 #include <linux/crc32.h>
25 MODULE_AUTHOR("Jouni Malinen");
26 MODULE_DESCRIPTION("Host AP crypt: WEP");
27 MODULE_LICENSE("GPL");
29 struct prism2_wep_data {
30 u32 iv;
31 #define WEP_KEY_LEN 13
32 u8 key[WEP_KEY_LEN + 1];
33 u8 key_len;
34 u8 key_idx;
35 struct crypto_tfm *tfm;
36 };
38 static void *prism2_wep_init(int keyidx)
39 {
40 struct prism2_wep_data *priv;
42 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
43 if (priv == NULL)
44 goto fail;
45 priv->key_idx = keyidx;
47 priv->tfm = crypto_alloc_tfm("arc4", 0);
48 if (priv->tfm == NULL) {
49 printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
50 "crypto API arc4\n");
51 goto fail;
52 }
54 /* start WEP IV from a random value */
55 get_random_bytes(&priv->iv, 4);
57 return priv;
59 fail:
60 if (priv) {
61 if (priv->tfm)
62 crypto_free_tfm(priv->tfm);
63 kfree(priv);
64 }
65 return NULL;
66 }
68 static void prism2_wep_deinit(void *priv)
69 {
70 struct prism2_wep_data *_priv = priv;
71 if (_priv && _priv->tfm)
72 crypto_free_tfm(_priv->tfm);
73 kfree(priv);
74 }
76 /* Add WEP IV/key info to a frame that has at least 4 bytes of headroom */
77 static int prism2_wep_build_iv(struct sk_buff *skb, int hdr_len,
78 u8 *key, int keylen, void *priv)
79 {
80 struct prism2_wep_data *wep = priv;
81 u32 klen, len;
82 u8 *pos;
84 if (skb_headroom(skb) < 4 || skb->len < hdr_len)
85 return -1;
87 len = skb->len - hdr_len;
88 pos = skb_push(skb, 4);
89 memmove(pos, pos + 4, hdr_len);
90 pos += hdr_len;
92 klen = 3 + wep->key_len;
94 wep->iv++;
96 /* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
97 * scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
98 * can be used to speedup attacks, so avoid using them. */
99 if ((wep->iv & 0xff00) == 0xff00) {
100 u8 B = (wep->iv >> 16) & 0xff;
101 if (B >= 3 && B < klen)
102 wep->iv += 0x0100;
103 }
105 /* Prepend 24-bit IV to RC4 key and TX frame */
106 *pos++ = (wep->iv >> 16) & 0xff;
107 *pos++ = (wep->iv >> 8) & 0xff;
108 *pos++ = wep->iv & 0xff;
109 *pos++ = wep->key_idx << 6;
111 return 0;
112 }
114 /* Perform WEP encryption on given skb that has at least 4 bytes of headroom
115 * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
116 * so the payload length increases with 8 bytes.
117 *
118 * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
119 */
120 static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
121 {
122 struct prism2_wep_data *wep = priv;
123 u32 crc, klen, len;
124 u8 *pos, *icv;
125 struct scatterlist sg;
126 u8 key[WEP_KEY_LEN + 3];
128 /* other checks are in prism2_wep_build_iv */
129 if (skb_tailroom(skb) < 4)
130 return -1;
132 /* add the IV to the frame */
133 if (prism2_wep_build_iv(skb, hdr_len, NULL, 0, priv))
134 return -1;
136 /* Copy the IV into the first 3 bytes of the key */
137 memcpy(key, skb->data + hdr_len, 3);
139 /* Copy rest of the WEP key (the secret part) */
140 memcpy(key + 3, wep->key, wep->key_len);
142 len = skb->len - hdr_len - 4;
143 pos = skb->data + hdr_len + 4;
144 klen = 3 + wep->key_len;
146 /* Append little-endian CRC32 over only the data and encrypt it to produce ICV */
147 crc = ~crc32_le(~0, pos, len);
148 icv = skb_put(skb, 4);
149 icv[0] = crc;
150 icv[1] = crc >> 8;
151 icv[2] = crc >> 16;
152 icv[3] = crc >> 24;
154 crypto_cipher_setkey(wep->tfm, key, klen);
155 sg.page = virt_to_page(pos);
156 sg.offset = offset_in_page(pos);
157 sg.length = len + 4;
158 crypto_cipher_encrypt(wep->tfm, &sg, &sg, len + 4);
160 return 0;
161 }
163 /* Perform WEP decryption on given buffer. Buffer includes whole WEP part of
164 * the frame: IV (4 bytes), encrypted payload (including SNAP header),
165 * ICV (4 bytes). len includes both IV and ICV.
166 *
167 * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
168 * failure. If frame is OK, IV and ICV will be removed.
169 */
170 static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
171 {
172 struct prism2_wep_data *wep = priv;
173 u32 crc, klen, plen;
174 u8 key[WEP_KEY_LEN + 3];
175 u8 keyidx, *pos, icv[4];
176 struct scatterlist sg;
178 if (skb->len < hdr_len + 8)
179 return -1;
181 pos = skb->data + hdr_len;
182 key[0] = *pos++;
183 key[1] = *pos++;
184 key[2] = *pos++;
185 keyidx = *pos++ >> 6;
186 if (keyidx != wep->key_idx)
187 return -1;
189 klen = 3 + wep->key_len;
191 /* Copy rest of the WEP key (the secret part) */
192 memcpy(key + 3, wep->key, wep->key_len);
194 /* Apply RC4 to data and compute CRC32 over decrypted data */
195 plen = skb->len - hdr_len - 8;
197 crypto_cipher_setkey(wep->tfm, key, klen);
198 sg.page = virt_to_page(pos);
199 sg.offset = offset_in_page(pos);
200 sg.length = plen + 4;
201 crypto_cipher_decrypt(wep->tfm, &sg, &sg, plen + 4);
203 crc = ~crc32_le(~0, pos, plen);
204 icv[0] = crc;
205 icv[1] = crc >> 8;
206 icv[2] = crc >> 16;
207 icv[3] = crc >> 24;
208 if (memcmp(icv, pos + plen, 4) != 0) {
209 /* ICV mismatch - drop frame */
210 return -2;
211 }
213 /* Remove IV and ICV */
214 memmove(skb->data + 4, skb->data, hdr_len);
215 skb_pull(skb, 4);
216 skb_trim(skb, skb->len - 4);
218 return 0;
219 }
221 static int prism2_wep_set_key(void *key, int len, u8 * seq, void *priv)
222 {
223 struct prism2_wep_data *wep = priv;
225 if (len < 0 || len > WEP_KEY_LEN)
226 return -1;
228 memcpy(wep->key, key, len);
229 wep->key_len = len;
231 return 0;
232 }
234 static int prism2_wep_get_key(void *key, int len, u8 * seq, void *priv)
235 {
236 struct prism2_wep_data *wep = priv;
238 if (len < wep->key_len)
239 return -1;
241 memcpy(key, wep->key, wep->key_len);
243 return wep->key_len;
244 }
246 static char *prism2_wep_print_stats(char *p, void *priv)
247 {
248 struct prism2_wep_data *wep = priv;
249 p += sprintf(p, "key[%d] alg=WEP len=%d\n", wep->key_idx, wep->key_len);
250 return p;
251 }
253 static struct ieee80211_crypto_ops ieee80211_crypt_wep = {
254 .name = "WEP",
255 .init = prism2_wep_init,
256 .deinit = prism2_wep_deinit,
257 .build_iv = prism2_wep_build_iv,
258 .encrypt_mpdu = prism2_wep_encrypt,
259 .decrypt_mpdu = prism2_wep_decrypt,
260 .encrypt_msdu = NULL,
261 .decrypt_msdu = NULL,
262 .set_key = prism2_wep_set_key,
263 .get_key = prism2_wep_get_key,
264 .print_stats = prism2_wep_print_stats,
265 .extra_mpdu_prefix_len = 4, /* IV */
266 .extra_mpdu_postfix_len = 4, /* ICV */
267 .owner = THIS_MODULE,
268 };
270 static int __init ieee80211_crypto_wep_init(void)
271 {
272 return ieee80211_register_crypto_ops(&ieee80211_crypt_wep);
273 }
275 static void __exit ieee80211_crypto_wep_exit(void)
276 {
277 ieee80211_unregister_crypto_ops(&ieee80211_crypt_wep);
278 }
280 module_init(ieee80211_crypto_wep_init);
281 module_exit(ieee80211_crypto_wep_exit);