staging: rtl8192e: Convert typedef cb_desc to struct cb_desc
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / staging / rtl8192e / rtllib_crypt_wep.c
blob05aa2e2a90e24c6a569de0271f24debb124b2916
1 /*
2 * Host AP crypt: host-based WEP encryption implementation for Host AP driver
4 * Copyright (c) 2002-2004, Jouni Malinen <jkmaline@cc.hut.fi>
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.
12 #include <linux/version.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/random.h>
17 #include <linux/skbuff.h>
18 #include <asm/string.h>
19 #include "rtllib.h"
21 #include <linux/crypto.h>
23 #include <linux/scatterlist.h>
24 #include <linux/crc32.h>
26 struct prism2_wep_data {
27 u32 iv;
28 #define WEP_KEY_LEN 13
29 u8 key[WEP_KEY_LEN + 1];
30 u8 key_len;
31 u8 key_idx;
32 struct crypto_blkcipher *tx_tfm;
33 struct crypto_blkcipher *rx_tfm;
37 static void * prism2_wep_init(int keyidx)
39 struct prism2_wep_data *priv;
41 priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
42 if (priv == NULL)
43 goto fail;
44 memset(priv, 0, sizeof(*priv));
45 priv->key_idx = keyidx;
47 priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
48 if (IS_ERR(priv->tx_tfm)) {
49 printk(KERN_DEBUG "rtllib_crypt_wep: could not allocate "
50 "crypto API arc4\n");
51 priv->tx_tfm = NULL;
52 goto fail;
54 priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
55 if (IS_ERR(priv->rx_tfm)) {
56 printk(KERN_DEBUG "rtllib_crypt_wep: could not allocate "
57 "crypto API arc4\n");
58 priv->rx_tfm = NULL;
59 goto fail;
62 /* start WEP IV from a random value */
63 get_random_bytes(&priv->iv, 4);
65 return priv;
67 fail:
68 if (priv) {
69 if (priv->tx_tfm)
70 crypto_free_blkcipher(priv->tx_tfm);
71 if (priv->rx_tfm)
72 crypto_free_blkcipher(priv->rx_tfm);
73 kfree(priv);
75 return NULL;
79 static void prism2_wep_deinit(void *priv)
81 struct prism2_wep_data *_priv = priv;
83 if (_priv) {
84 if (_priv->tx_tfm)
85 crypto_free_blkcipher(_priv->tx_tfm);
86 if (_priv->rx_tfm)
87 crypto_free_blkcipher(_priv->rx_tfm);
89 kfree(priv);
92 /* Perform WEP encryption on given skb that has at least 4 bytes of headroom
93 * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
94 * so the payload length increases with 8 bytes.
96 * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
98 static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
100 struct prism2_wep_data *wep = priv;
101 u32 klen, len;
102 u8 key[WEP_KEY_LEN + 3];
103 u8 *pos;
104 struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
105 struct blkcipher_desc desc = {.tfm = wep->tx_tfm};
106 u32 crc;
107 u8 *icv;
108 struct scatterlist sg;
109 if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
110 skb->len < hdr_len){
111 printk("Error!!!headroom=%d tailroom=%d skblen=%d hdr_len=%d\n",skb_headroom(skb),skb_tailroom(skb),skb->len,hdr_len);
112 return -1;
114 len = skb->len - hdr_len;
115 pos = skb_push(skb, 4);
116 memmove(pos, pos + 4, hdr_len);
117 pos += hdr_len;
119 klen = 3 + wep->key_len;
121 wep->iv++;
123 /* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
124 * scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
125 * can be used to speedup attacks, so avoid using them. */
126 if ((wep->iv & 0xff00) == 0xff00) {
127 u8 B = (wep->iv >> 16) & 0xff;
128 if (B >= 3 && B < klen)
129 wep->iv += 0x0100;
132 /* Prepend 24-bit IV to RC4 key and TX frame */
133 *pos++ = key[0] = (wep->iv >> 16) & 0xff;
134 *pos++ = key[1] = (wep->iv >> 8) & 0xff;
135 *pos++ = key[2] = wep->iv & 0xff;
136 *pos++ = wep->key_idx << 6;
138 /* Copy rest of the WEP key (the secret part) */
139 memcpy(key + 3, wep->key, wep->key_len);
141 if (!tcb_desc->bHwSec) {
143 /* Append little-endian CRC32 and encrypt it to produce ICV */
144 crc = ~crc32_le(~0, pos, len);
145 icv = skb_put(skb, 4);
146 icv[0] = crc;
147 icv[1] = crc >> 8;
148 icv[2] = crc >> 16;
149 icv[3] = crc >> 24;
151 sg_init_one(&sg, pos, len+4);
152 crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
153 return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
156 return 0;
160 /* Perform WEP decryption on given buffer. Buffer includes whole WEP part of
161 * the frame: IV (4 bytes), encrypted payload (including SNAP header),
162 * ICV (4 bytes). len includes both IV and ICV.
164 * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
165 * failure. If frame is OK, IV and ICV will be removed.
167 static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
169 struct prism2_wep_data *wep = priv;
170 u32 klen, plen;
171 u8 key[WEP_KEY_LEN + 3];
172 u8 keyidx, *pos;
173 struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
174 struct blkcipher_desc desc = {.tfm = wep->rx_tfm};
175 u32 crc;
176 u8 icv[4];
177 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 if (!tcb_desc->bHwSec) {
198 sg_init_one(&sg, pos, plen+4);
199 crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
200 if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
201 return -7;
202 crc = ~crc32_le(~0, pos, plen);
203 icv[0] = crc;
204 icv[1] = crc >> 8;
205 icv[2] = crc >> 16;
206 icv[3] = crc >> 24;
207 if (memcmp(icv, pos + plen, 4) != 0) {
208 /* ICV mismatch - drop frame */
209 return -2;
212 /* Remove IV and ICV */
213 memmove(skb->data + 4, skb->data, hdr_len);
214 skb_pull(skb, 4);
215 skb_trim(skb, skb->len - 4);
217 return 0;
221 static int prism2_wep_set_key(void *key, int len, u8 *seq, void *priv)
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;
235 static int prism2_wep_get_key(void *key, int len, u8 *seq, void *priv)
237 struct prism2_wep_data *wep = priv;
239 if (len < wep->key_len)
240 return -1;
242 memcpy(key, wep->key, wep->key_len);
244 return wep->key_len;
248 static char * prism2_wep_print_stats(char *p, void *priv)
250 struct prism2_wep_data *wep = priv;
251 p += sprintf(p, "key[%d] alg=WEP len=%d\n",
252 wep->key_idx, wep->key_len);
253 return p;
257 static struct rtllib_crypto_ops rtllib_crypt_wep = {
258 .name = "WEP",
259 .init = prism2_wep_init,
260 .deinit = prism2_wep_deinit,
261 .encrypt_mpdu = prism2_wep_encrypt,
262 .decrypt_mpdu = prism2_wep_decrypt,
263 .encrypt_msdu = NULL,
264 .decrypt_msdu = NULL,
265 .set_key = prism2_wep_set_key,
266 .get_key = prism2_wep_get_key,
267 .print_stats = prism2_wep_print_stats,
268 .extra_prefix_len = 4, /* IV */
269 .extra_postfix_len = 4, /* ICV */
270 .owner = THIS_MODULE,
274 int __init rtllib_crypto_wep_init(void)
276 return rtllib_register_crypto_ops(&rtllib_crypt_wep);
280 void __exit rtllib_crypto_wep_exit(void)
282 rtllib_unregister_crypto_ops(&rtllib_crypt_wep);
285 void rtllib_wep_null(void)
287 return;