LXR linux/drivers/staging/rtl8192e/ieee80211/ieee80211_crypt

   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 */
  11
  12//#include <linux/config.h>
  13#include <linux/version.h>
  14#include <linux/module.h>
  15#include <linux/init.h>
  16#include <linux/slab.h>
  17#include <linux/random.h>
  18#include <linux/skbuff.h>
  19#include <asm/string.h>
  20
  21#include "ieee80211.h"
  22
  23
  24#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
  25#include "rtl_crypto.h"
  26#else
  27#include <linux/crypto.h>
  28#endif
  29
  30#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
  31    #include <asm/scatterlist.h>
  32#else
  33    #include <linux/scatterlist.h>
  34#endif
  35//#include <asm/scatterlist.h>
  36#include <linux/crc32.h>
  37//
  38/*
  39#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
  40#include "rtl_crypto.h"
  41#else
  42#include <linux/crypto.h>
  43#endif
  44
  45#include <asm/scatterlist.h>
  46#include <linux/crc32.h>
  47*/
  48MODULE_AUTHOR("Jouni Malinen");
  49MODULE_DESCRIPTION("Host AP crypt: WEP");
  50MODULE_LICENSE("GPL");
  51#ifndef OPENSUSE_SLED
  52#define OPENSUSE_SLED 0
  53#endif
  54
  55struct prism2_wep_data {
  56        u32 iv;
  57#define WEP_KEY_LEN 13
  58        u8 key[WEP_KEY_LEN + 1];
  59        u8 key_len;
  60        u8 key_idx;
  61#if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
  62        struct crypto_tfm *tfm;
  63        #else
  64        struct crypto_blkcipher *tx_tfm;
  65        struct crypto_blkcipher *rx_tfm;
  66        #endif
  67};
  68
  69
  70static void * prism2_wep_init(int keyidx)
  71{
  72        struct prism2_wep_data *priv;
  73
  74        priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
  75        if (priv == NULL)
  76                goto fail;
  77        memset(priv, 0, sizeof(*priv));
  78        priv->key_idx = keyidx;
  79
  80#if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
  81        priv->tfm = crypto_alloc_tfm("arc4", 0);
  82        if (priv->tfm == NULL) {
  83                printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
  84                       "crypto API arc4\n");
  85                goto fail;
  86        }
  87        #else
  88        priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
  89        if (IS_ERR(priv->tx_tfm)) {
  90                printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
  91                       "crypto API arc4\n");
  92                priv->tx_tfm = NULL;
  93                goto fail;
  94        }
  95        priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
  96        if (IS_ERR(priv->rx_tfm)) {
  97                printk(KERN_DEBUG "ieee80211_crypt_wep: could not allocate "
  98                       "crypto API arc4\n");
  99                priv->rx_tfm = NULL;
 100                goto fail;
 101        }
 102        #endif
 103
 104        /* start WEP IV from a random value */
 105        get_random_bytes(&priv->iv, 4);
 106
 107        return priv;
 108
 109fail:
 110#if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
 111        if (priv) {
 112                if (priv->tfm)
 113                        crypto_free_tfm(priv->tfm);
 114                kfree(priv);
 115        }
 116        #else
 117        if (priv) {
 118                if (priv->tx_tfm)
 119                        crypto_free_blkcipher(priv->tx_tfm);
 120                if (priv->rx_tfm)
 121                        crypto_free_blkcipher(priv->rx_tfm);
 122                kfree(priv);
 123        }
 124        #endif
 125        return NULL;
 126}
 127
 128
 129static void prism2_wep_deinit(void *priv)
 130{
 131        struct prism2_wep_data *_priv = priv;
 132#if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
 133        if (_priv && _priv->tfm)
 134                crypto_free_tfm(_priv->tfm);
 135        #else
 136        if (_priv) {
 137                if (_priv->tx_tfm)
 138                        crypto_free_blkcipher(_priv->tx_tfm);
 139                if (_priv->rx_tfm)
 140                        crypto_free_blkcipher(_priv->rx_tfm);
 141        }
 142        #endif
 143        kfree(priv);
 144}
 145
 146/* Perform WEP encryption on given skb that has at least 4 bytes of headroom
 147 * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted,
 148 * so the payload length increases with 8 bytes.
 149 *
 150 * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
 151 */
 152static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 153{
 154        struct prism2_wep_data *wep = priv;
 155        u32 klen, len;
 156        u8 key[WEP_KEY_LEN + 3];
 157        u8 *pos;
 158        cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 159        #if((LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)) || (OPENSUSE_SLED))
 160        struct blkcipher_desc desc = {.tfm = wep->tx_tfm};
 161        #endif
 162        u32 crc;
 163        u8 *icv;
 164        struct scatterlist sg;
 165        if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
 166            skb->len < hdr_len)
 167                return -1;
 168
 169        len = skb->len - hdr_len;
 170        pos = skb_push(skb, 4);
 171        memmove(pos, pos + 4, hdr_len);
 172        pos += hdr_len;
 173
 174        klen = 3 + wep->key_len;
 175
 176        wep->iv++;
 177
 178        /* Fluhrer, Mantin, and Shamir have reported weaknesses in the key
 179         * scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N)
 180         * can be used to speedup attacks, so avoid using them. */
 181        if ((wep->iv & 0xff00) == 0xff00) {
 182                u8 B = (wep->iv >> 16) & 0xff;
 183                if (B >= 3 && B < klen)
 184                        wep->iv += 0x0100;
 185        }
 186
 187        /* Prepend 24-bit IV to RC4 key and TX frame */
 188        *pos++ = key[0] = (wep->iv >> 16) & 0xff;
 189        *pos++ = key[1] = (wep->iv >> 8) & 0xff;
 190        *pos++ = key[2] = wep->iv & 0xff;
 191        *pos++ = wep->key_idx << 6;
 192
 193        /* Copy rest of the WEP key (the secret part) */
 194        memcpy(key + 3, wep->key, wep->key_len);
 195
 196        if (!tcb_desc->bHwSec)
 197        {
 198
 199                /* Append little-endian CRC32 and encrypt it to produce ICV */
 200        #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
 201                crc = ~crc32_le(~0, pos, len);
 202        #else
 203                crc = ~ether_crc_le(len, pos);
 204        #endif
 205                icv = skb_put(skb, 4);
 206                icv[0] = crc;
 207                icv[1] = crc >> 8;
 208                icv[2] = crc >> 16;
 209                icv[3] = crc >> 24;
 210
 211#if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
 212                crypto_cipher_setkey(wep->tfm, key, klen);
 213                sg.page = virt_to_page(pos);
 214                sg.offset = offset_in_page(pos);
 215                sg.length = len + 4;
 216                crypto_cipher_encrypt(wep->tfm, &sg, &sg, len + 4);
 217                return 0;
 218        #else
 219                crypto_blkcipher_setkey(wep->tx_tfm, key, klen);
 220        #if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24))
 221                sg.page = virt_to_page(pos);
 222                sg.offset = offset_in_page(pos);
 223                sg.length = len + 4;
 224        #else
 225                sg_init_one(&sg, pos, len+4);
 226        #endif
 227                return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
 228        #endif
 229        }
 230
 231        return 0;
 232}
 233
 234
 235/* Perform WEP decryption on given buffer. Buffer includes whole WEP part of
 236 * the frame: IV (4 bytes), encrypted payload (including SNAP header),
 237 * ICV (4 bytes). len includes both IV and ICV.
 238 *
 239 * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
 240 * failure. If frame is OK, IV and ICV will be removed.
 241 */
 242static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 243{
 244        struct prism2_wep_data *wep = priv;
 245        u32  klen, plen;
 246        u8 key[WEP_KEY_LEN + 3];
 247        u8 keyidx, *pos;
 248        cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 249        #if((LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)) || (OPENSUSE_SLED))
 250        struct blkcipher_desc desc = {.tfm = wep->rx_tfm};
 251        #endif
 252        u32 crc;
 253        u8 icv[4];
 254        struct scatterlist sg;
 255        if (skb->len < hdr_len + 8)
 256                return -1;
 257
 258        pos = skb->data + hdr_len;
 259        key[0] = *pos++;
 260        key[1] = *pos++;
 261        key[2] = *pos++;
 262        keyidx = *pos++ >> 6;
 263        if (keyidx != wep->key_idx)
 264                return -1;
 265
 266        klen = 3 + wep->key_len;
 267
 268        /* Copy rest of the WEP key (the secret part) */
 269        memcpy(key + 3, wep->key, wep->key_len);
 270
 271        /* Apply RC4 to data and compute CRC32 over decrypted data */
 272        plen = skb->len - hdr_len - 8;
 273
 274        if (!tcb_desc->bHwSec)
 275        {
 276#if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
 277                crypto_cipher_setkey(wep->tfm, key, klen);
 278                sg.page = virt_to_page(pos);
 279                sg.offset = offset_in_page(pos);
 280                sg.length = plen + 4;
 281                crypto_cipher_decrypt(wep->tfm, &sg, &sg, plen + 4);
 282        #else
 283                crypto_blkcipher_setkey(wep->rx_tfm, key, klen);
 284        #if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24))
 285                sg.page = virt_to_page(pos);
 286                sg.offset = offset_in_page(pos);
 287                sg.length = plen + 4;
 288        #else
 289                sg_init_one(&sg, pos, plen+4);
 290        #endif
 291                if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4))
 292                        return -7;
 293        #endif
 294        #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
 295                crc = ~crc32_le(~0, pos, plen);
 296        #else
 297                crc = ~ether_crc_le(plen, pos);
 298        #endif
 299                icv[0] = crc;
 300                icv[1] = crc >> 8;
 301                icv[2] = crc >> 16;
 302                icv[3] = crc >> 24;
 303                if (memcmp(icv, pos + plen, 4) != 0) {
 304                        /* ICV mismatch - drop frame */
 305                        return -2;
 306                }
 307        }
 308        /* Remove IV and ICV */
 309        memmove(skb->data + 4, skb->data, hdr_len);
 310        skb_pull(skb, 4);
 311        skb_trim(skb, skb->len - 4);
 312
 313        return 0;
 314}
 315
 316
 317static int prism2_wep_set_key(void *key, int len, u8 *seq, void *priv)
 318{
 319        struct prism2_wep_data *wep = priv;
 320
 321        if (len < 0 || len > WEP_KEY_LEN)
 322                return -1;
 323
 324        memcpy(wep->key, key, len);
 325        wep->key_len = len;
 326
 327        return 0;
 328}
 329
 330
 331static int prism2_wep_get_key(void *key, int len, u8 *seq, void *priv)
 332{
 333        struct prism2_wep_data *wep = priv;
 334
 335        if (len < wep->key_len)
 336                return -1;
 337
 338        memcpy(key, wep->key, wep->key_len);
 339
 340        return wep->key_len;
 341}
 342
 343
 344static char * prism2_wep_print_stats(char *p, void *priv)
 345{
 346        struct prism2_wep_data *wep = priv;
 347        p += sprintf(p, "key[%d] alg=WEP len=%d\n",
 348                     wep->key_idx, wep->key_len);
 349        return p;
 350}
 351
 352
 353static struct ieee80211_crypto_ops ieee80211_crypt_wep = {
 354        .name                   = "WEP",
 355        .init                   = prism2_wep_init,
 356        .deinit                 = prism2_wep_deinit,
 357        .encrypt_mpdu           = prism2_wep_encrypt,
 358        .decrypt_mpdu           = prism2_wep_decrypt,
 359        .encrypt_msdu           = NULL,
 360        .decrypt_msdu           = NULL,
 361        .set_key                = prism2_wep_set_key,
 362        .get_key                = prism2_wep_get_key,
 363        .print_stats            = prism2_wep_print_stats,
 364        .extra_prefix_len       = 4, /* IV */
 365        .extra_postfix_len      = 4, /* ICV */
 366        .owner                  = THIS_MODULE,
 367};
 368
 369
 370int __init ieee80211_crypto_wep_init(void)
 371{
 372        return ieee80211_register_crypto_ops(&ieee80211_crypt_wep);
 373}
 374
 375
 376void __exit ieee80211_crypto_wep_exit(void)
 377{
 378        ieee80211_unregister_crypto_ops(&ieee80211_crypt_wep);
 379}
 380
 381void ieee80211_wep_null(void)
 382{
 383//      printk("============>%s()\n", __FUNCTION__);
 384        return;
 385}
 386#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
 387//EXPORT_SYMBOL(ieee80211_wep_null);
 388#else
 389EXPORT_SYMBOL_NOVERS(ieee80211_wep_null);
 390#endif
 391
 392//module_init(ieee80211_crypto_wep_init);
 393//module_exit(ieee80211_crypto_wep_exit);
 394