kernel/net/wireless/lib80211_crypt_tkip.c

   1 /*
   2  * lib80211 crypt: host-based TKIP encryption implementation for lib80211
   3  *
   4  * Copyright (c) 2003-2004, Jouni Malinen <j@w1.fi>
   5  * Copyright (c) 2008, John W. Linville <linville@tuxdriver.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation. See README and COPYING for
  10  * more details.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/err.h>
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/random.h>
  20 #include <linux/scatterlist.h>
  21 #include <linux/skbuff.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/mm.h>
  24 #include <linux/if_ether.h>
  25 #include <linux/if_arp.h>
  26 #include <asm/string.h>
  27
  28 #include <linux/wireless.h>
  29 #include <linux/ieee80211.h>
  30 #include <net/iw_handler.h>
  31
  32 #include <linux/crypto.h>
  33 #include <linux/crc32.h>
  34
  35 #include <net/lib80211.h>
  36
  37 MODULE_AUTHOR("Jouni Malinen");
  38 MODULE_DESCRIPTION("lib80211 crypt: TKIP");
  39 MODULE_LICENSE("GPL");
  40
  41 #define TKIP_HDR_LEN 8
  42
  43 struct lib80211_tkip_data {
  44 #define TKIP_KEY_LEN 32
  45         u8 key[TKIP_KEY_LEN];
  46         int key_set;
  47
  48         u32 tx_iv32;
  49         u16 tx_iv16;
  50         u16 tx_ttak[5];
  51         int tx_phase1_done;
  52
  53         u32 rx_iv32;
  54         u16 rx_iv16;
  55         u16 rx_ttak[5];
  56         int rx_phase1_done;
  57         u32 rx_iv32_new;
  58         u16 rx_iv16_new;
  59
  60         u32 dot11RSNAStatsTKIPReplays;
  61         u32 dot11RSNAStatsTKIPICVErrors;
  62         u32 dot11RSNAStatsTKIPLocalMICFailures;
  63
  64         int key_idx;
  65
  66         struct crypto_blkcipher *rx_tfm_arc4;
  67         struct crypto_hash *rx_tfm_michael;
  68         struct crypto_blkcipher *tx_tfm_arc4;
  69         struct crypto_hash *tx_tfm_michael;
  70
  71         /* scratch buffers for virt_to_page() (crypto API) */
  72         u8 rx_hdr[16], tx_hdr[16];
  73
  74         unsigned long flags;
  75 };
  76
  77 static unsigned long lib80211_tkip_set_flags(unsigned long flags, void *priv)
  78 {
  79         struct lib80211_tkip_data *_priv = priv;
  80         unsigned long old_flags = _priv->flags;
  81         _priv->flags = flags;
  82         return old_flags;
  83 }
  84
  85 static unsigned long lib80211_tkip_get_flags(void *priv)
  86 {
  87         struct lib80211_tkip_data *_priv = priv;
  88         return _priv->flags;
  89 }
  90
  91 static void *lib80211_tkip_init(int key_idx)
  92 {
  93         struct lib80211_tkip_data *priv;
  94
  95         priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
  96         if (priv == NULL)
  97                 goto fail;
  98
  99         priv->key_idx = key_idx;
 100
 101         priv->tx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,
 102                                                 CRYPTO_ALG_ASYNC);
 103         if (IS_ERR(priv->tx_tfm_arc4)) {
 104                 priv->tx_tfm_arc4 = NULL;
 105                 goto fail;
 106         }
 107
 108         priv->tx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
 109                                                  CRYPTO_ALG_ASYNC);
 110         if (IS_ERR(priv->tx_tfm_michael)) {
 111                 priv->tx_tfm_michael = NULL;
 112                 goto fail;
 113         }
 114
 115         priv->rx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,
 116                                                 CRYPTO_ALG_ASYNC);
 117         if (IS_ERR(priv->rx_tfm_arc4)) {
 118                 priv->rx_tfm_arc4 = NULL;
 119                 goto fail;
 120         }
 121
 122         priv->rx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
 123                                                  CRYPTO_ALG_ASYNC);
 124         if (IS_ERR(priv->rx_tfm_michael)) {
 125                 priv->rx_tfm_michael = NULL;
 126                 goto fail;
 127         }
 128
 129         return priv;
 130
 131       fail:
 132         if (priv) {
 133                 if (priv->tx_tfm_michael)
 134                         crypto_free_hash(priv->tx_tfm_michael);
 135                 if (priv->tx_tfm_arc4)
 136                         crypto_free_blkcipher(priv->tx_tfm_arc4);
 137                 if (priv->rx_tfm_michael)
 138                         crypto_free_hash(priv->rx_tfm_michael);
 139                 if (priv->rx_tfm_arc4)
 140                         crypto_free_blkcipher(priv->rx_tfm_arc4);
 141                 kfree(priv);
 142         }
 143
 144         return NULL;
 145 }
 146
 147 static void lib80211_tkip_deinit(void *priv)
 148 {
 149         struct lib80211_tkip_data *_priv = priv;
 150         if (_priv) {
 151                 if (_priv->tx_tfm_michael)
 152                         crypto_free_hash(_priv->tx_tfm_michael);
 153                 if (_priv->tx_tfm_arc4)
 154                         crypto_free_blkcipher(_priv->tx_tfm_arc4);
 155                 if (_priv->rx_tfm_michael)
 156                         crypto_free_hash(_priv->rx_tfm_michael);
 157                 if (_priv->rx_tfm_arc4)
 158                         crypto_free_blkcipher(_priv->rx_tfm_arc4);
 159         }
 160         kfree(priv);
 161 }
 162
 163 static inline u16 RotR1(u16 val)
 164 {
 165         return (val >> 1) | (val << 15);
 166 }
 167
 168 static inline u8 Lo8(u16 val)
 169 {
 170         return val & 0xff;
 171 }
 172
 173 static inline u8 Hi8(u16 val)
 174 {
 175         return val >> 8;
 176 }
 177
 178 static inline u16 Lo16(u32 val)
 179 {
 180         return val & 0xffff;
 181 }
 182
 183 static inline u16 Hi16(u32 val)
 184 {
 185         return val >> 16;
 186 }
 187
 188 static inline u16 Mk16(u8 hi, u8 lo)
 189 {
 190         return lo | (((u16) hi) << 8);
 191 }
 192
 193 static inline u16 Mk16_le(__le16 * v)
 194 {
 195         return le16_to_cpu(*v);
 196 }
 197
 198 static const u16 Sbox[256] = {
 199         0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
 200         0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
 201         0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
 202         0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
 203         0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
 204         0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
 205         0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
 206         0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
 207         0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
 208         0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
 209         0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
 210         0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
 211         0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
 212         0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
 213         0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
 214         0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
 215         0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
 216         0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
 217         0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
 218         0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
 219         0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
 220         0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
 221         0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
 222         0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
 223         0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
 224         0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
 225         0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
 226         0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
 227         0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
 228         0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
 229         0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
 230         0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
 231 };
 232
 233 static inline u16 _S_(u16 v)
 234 {
 235         u16 t = Sbox[Hi8(v)];
 236         return Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8));
 237 }
 238
 239 #define PHASE1_LOOP_COUNT 8
 240
 241 static void tkip_mixing_phase1(u16 * TTAK, const u8 * TK, const u8 * TA,
 242                                u32 IV32)
 243 {
 244         int i, j;
 245
 246         /* Initialize the 80-bit TTAK from TSC (IV32) and TA[0..5] */
 247         TTAK[0] = Lo16(IV32);
 248         TTAK[1] = Hi16(IV32);
 249         TTAK[2] = Mk16(TA[1], TA[0]);
 250         TTAK[3] = Mk16(TA[3], TA[2]);
 251         TTAK[4] = Mk16(TA[5], TA[4]);
 252
 253         for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
 254                 j = 2 * (i & 1);
 255                 TTAK[0] += _S_(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]));
 256                 TTAK[1] += _S_(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]));
 257                 TTAK[2] += _S_(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]));
 258                 TTAK[3] += _S_(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]));
 259                 TTAK[4] += _S_(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j])) + i;
 260         }
 261 }
 262
 263 static void tkip_mixing_phase2(u8 * WEPSeed, const u8 * TK, const u16 * TTAK,
 264                                u16 IV16)
 265 {
 266         /* Make temporary area overlap WEP seed so that the final copy can be
 267          * avoided on little endian hosts. */
 268         u16 *PPK = (u16 *) & WEPSeed[4];
 269
 270         /* Step 1 - make copy of TTAK and bring in TSC */
 271         PPK[0] = TTAK[0];
 272         PPK[1] = TTAK[1];
 273         PPK[2] = TTAK[2];
 274         PPK[3] = TTAK[3];
 275         PPK[4] = TTAK[4];
 276         PPK[5] = TTAK[4] + IV16;
 277
 278         /* Step 2 - 96-bit bijective mixing using S-box */
 279         PPK[0] += _S_(PPK[5] ^ Mk16_le((__le16 *) & TK[0]));
 280         PPK[1] += _S_(PPK[0] ^ Mk16_le((__le16 *) & TK[2]));
 281         PPK[2] += _S_(PPK[1] ^ Mk16_le((__le16 *) & TK[4]));
 282         PPK[3] += _S_(PPK[2] ^ Mk16_le((__le16 *) & TK[6]));
 283         PPK[4] += _S_(PPK[3] ^ Mk16_le((__le16 *) & TK[8]));
 284         PPK[5] += _S_(PPK[4] ^ Mk16_le((__le16 *) & TK[10]));
 285
 286         PPK[0] += RotR1(PPK[5] ^ Mk16_le((__le16 *) & TK[12]));
 287         PPK[1] += RotR1(PPK[0] ^ Mk16_le((__le16 *) & TK[14]));
 288         PPK[2] += RotR1(PPK[1]);
 289         PPK[3] += RotR1(PPK[2]);
 290         PPK[4] += RotR1(PPK[3]);
 291         PPK[5] += RotR1(PPK[4]);
 292
 293         /* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
 294          * WEPSeed[0..2] is transmitted as WEP IV */
 295         WEPSeed[0] = Hi8(IV16);
 296         WEPSeed[1] = (Hi8(IV16) | 0x20) & 0x7F;
 297         WEPSeed[2] = Lo8(IV16);
 298         WEPSeed[3] = Lo8((PPK[5] ^ Mk16_le((__le16 *) & TK[0])) >> 1);
 299
 300 #ifdef __BIG_ENDIAN
 301         {
 302                 int i;
 303                 for (i = 0; i < 6; i++)
 304                         PPK[i] = (PPK[i] << 8) | (PPK[i] >> 8);
 305         }
 306 #endif
 307 }
 308
 309 static int lib80211_tkip_hdr(struct sk_buff *skb, int hdr_len,
 310                               u8 * rc4key, int keylen, void *priv)
 311 {
 312         struct lib80211_tkip_data *tkey = priv;
 313         u8 *pos;
 314         struct ieee80211_hdr *hdr;
 315
 316         hdr = (struct ieee80211_hdr *)skb->data;
 317
 318         if (skb_headroom(skb) < TKIP_HDR_LEN || skb->len < hdr_len)
 319                 return -1;
 320
 321         if (rc4key == NULL || keylen < 16)
 322                 return -1;
 323
 324         if (!tkey->tx_phase1_done) {
 325                 tkip_mixing_phase1(tkey->tx_ttak, tkey->key, hdr->addr2,
 326                                    tkey->tx_iv32);
 327                 tkey->tx_phase1_done = 1;
 328         }
 329         tkip_mixing_phase2(rc4key, tkey->key, tkey->tx_ttak, tkey->tx_iv16);
 330
 331         pos = skb_push(skb, TKIP_HDR_LEN);
 332         memmove(pos, pos + TKIP_HDR_LEN, hdr_len);
 333         pos += hdr_len;
 334
 335         *pos++ = *rc4key;
 336         *pos++ = *(rc4key + 1);
 337         *pos++ = *(rc4key + 2);
 338         *pos++ = (tkey->key_idx << 6) | (1 << 5) /* Ext IV included */ ;
 339         *pos++ = tkey->tx_iv32 & 0xff;
 340         *pos++ = (tkey->tx_iv32 >> 8) & 0xff;
 341         *pos++ = (tkey->tx_iv32 >> 16) & 0xff;
 342         *pos++ = (tkey->tx_iv32 >> 24) & 0xff;
 343
 344         tkey->tx_iv16++;
 345         if (tkey->tx_iv16 == 0) {
 346                 tkey->tx_phase1_done = 0;
 347                 tkey->tx_iv32++;
 348         }
 349
 350         return TKIP_HDR_LEN;
 351 }
 352
 353 static int lib80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 354 {
 355         struct lib80211_tkip_data *tkey = priv;
 356         struct blkcipher_desc desc = { .tfm = tkey->tx_tfm_arc4 };
 357         int len;
 358         u8 rc4key[16], *pos, *icv;
 359         u32 crc;
 360         struct scatterlist sg;
 361
 362         if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
 363                 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 364                 net_dbg_ratelimited("TKIP countermeasures: dropped TX packet to %pM\n",
 365                                     hdr->addr1);
 366                 return -1;
 367         }
 368
 369         if (skb_tailroom(skb) < 4 || skb->len < hdr_len)
 370                 return -1;
 371
 372         len = skb->len - hdr_len;
 373         pos = skb->data + hdr_len;
 374
 375         if ((lib80211_tkip_hdr(skb, hdr_len, rc4key, 16, priv)) < 0)
 376                 return -1;
 377
 378         crc = ~crc32_le(~0, pos, len);
 379         icv = skb_put(skb, 4);
 380         icv[0] = crc;
 381         icv[1] = crc >> 8;
 382         icv[2] = crc >> 16;
 383         icv[3] = crc >> 24;
 384
 385         crypto_blkcipher_setkey(tkey->tx_tfm_arc4, rc4key, 16);
 386         sg_init_one(&sg, pos, len + 4);
 387         return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
 388 }
 389
 390 /*
 391  * deal with seq counter wrapping correctly.
 392  * refer to timer_after() for jiffies wrapping handling
 393  */
 394 static inline int tkip_replay_check(u32 iv32_n, u16 iv16_n,
 395                                     u32 iv32_o, u16 iv16_o)
 396 {
 397         if ((s32)iv32_n - (s32)iv32_o < 0 ||
 398             (iv32_n == iv32_o && iv16_n <= iv16_o))
 399                 return 1;
 400         return 0;
 401 }
 402
 403 static int lib80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 404 {
 405         struct lib80211_tkip_data *tkey = priv;
 406         struct blkcipher_desc desc = { .tfm = tkey->rx_tfm_arc4 };
 407         u8 rc4key[16];
 408         u8 keyidx, *pos;
 409         u32 iv32;
 410         u16 iv16;
 411         struct ieee80211_hdr *hdr;
 412         u8 icv[4];
 413         u32 crc;
 414         struct scatterlist sg;
 415         int plen;
 416
 417         hdr = (struct ieee80211_hdr *)skb->data;
 418
 419         if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
 420                 net_dbg_ratelimited("TKIP countermeasures: dropped received packet from %pM\n",
 421                                     hdr->addr2);
 422                 return -1;
 423         }
 424
 425         if (skb->len < hdr_len + TKIP_HDR_LEN + 4)
 426                 return -1;
 427
 428         pos = skb->data + hdr_len;
 429         keyidx = pos[3];
 430         if (!(keyidx & (1 << 5))) {
 431                 net_dbg_ratelimited("TKIP: received packet without ExtIV flag from %pM\n",
 432                                     hdr->addr2);
 433                 return -2;
 434         }
 435         keyidx >>= 6;
 436         if (tkey->key_idx != keyidx) {
 437                 printk(KERN_DEBUG "TKIP: RX tkey->key_idx=%d frame "
 438                        "keyidx=%d priv=%p\n", tkey->key_idx, keyidx, priv);
 439                 return -6;
 440         }
 441         if (!tkey->key_set) {
 442                 net_dbg_ratelimited("TKIP: received packet from %pM with keyid=%d that does not have a configured key\n",
 443                                     hdr->addr2, keyidx);
 444                 return -3;
 445         }
 446         iv16 = (pos[0] << 8) | pos[2];
 447         iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24);
 448         pos += TKIP_HDR_LEN;
 449
 450         if (tkip_replay_check(iv32, iv16, tkey->rx_iv32, tkey->rx_iv16)) {
 451 #ifdef CONFIG_LIB80211_DEBUG
 452                 net_dbg_ratelimited("TKIP: replay detected: STA=%pM previous TSC %08x%04x received TSC %08x%04x\n",
 453                                     hdr->addr2, tkey->rx_iv32, tkey->rx_iv16,
 454                                     iv32, iv16);
 455 #endif
 456                 tkey->dot11RSNAStatsTKIPReplays++;
 457                 return -4;
 458         }
 459
 460         if (iv32 != tkey->rx_iv32 || !tkey->rx_phase1_done) {
 461                 tkip_mixing_phase1(tkey->rx_ttak, tkey->key, hdr->addr2, iv32);
 462                 tkey->rx_phase1_done = 1;
 463         }
 464         tkip_mixing_phase2(rc4key, tkey->key, tkey->rx_ttak, iv16);
 465
 466         plen = skb->len - hdr_len - 12;
 467
 468         crypto_blkcipher_setkey(tkey->rx_tfm_arc4, rc4key, 16);
 469         sg_init_one(&sg, pos, plen + 4);
 470         if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4)) {
 471                 net_dbg_ratelimited("TKIP: failed to decrypt received packet from %pM\n",
 472                                     hdr->addr2);
 473                 return -7;
 474         }
 475
 476         crc = ~crc32_le(~0, pos, plen);
 477         icv[0] = crc;
 478         icv[1] = crc >> 8;
 479         icv[2] = crc >> 16;
 480         icv[3] = crc >> 24;
 481         if (memcmp(icv, pos + plen, 4) != 0) {
 482                 if (iv32 != tkey->rx_iv32) {
 483                         /* Previously cached Phase1 result was already lost, so
 484                          * it needs to be recalculated for the next packet. */
 485                         tkey->rx_phase1_done = 0;
 486                 }
 487 #ifdef CONFIG_LIB80211_DEBUG
 488                 net_dbg_ratelimited("TKIP: ICV error detected: STA=%pM\n",
 489                                     hdr->addr2);
 490 #endif
 491                 tkey->dot11RSNAStatsTKIPICVErrors++;
 492                 return -5;
 493         }
 494
 495         /* Update real counters only after Michael MIC verification has
 496          * completed */
 497         tkey->rx_iv32_new = iv32;
 498         tkey->rx_iv16_new = iv16;
 499
 500         /* Remove IV and ICV */
 501         memmove(skb->data + TKIP_HDR_LEN, skb->data, hdr_len);
 502         skb_pull(skb, TKIP_HDR_LEN);
 503         skb_trim(skb, skb->len - 4);
 504
 505         return keyidx;
 506 }
 507
 508 static int michael_mic(struct crypto_hash *tfm_michael, u8 * key, u8 * hdr,
 509                        u8 * data, size_t data_len, u8 * mic)
 510 {
 511         struct hash_desc desc;
 512         struct scatterlist sg[2];
 513
 514         if (tfm_michael == NULL) {
 515                 pr_warn("%s(): tfm_michael == NULL\n", __func__);
 516                 return -1;
 517         }
 518         sg_init_table(sg, 2);
 519         sg_set_buf(&sg[0], hdr, 16);
 520         sg_set_buf(&sg[1], data, data_len);
 521
 522         if (crypto_hash_setkey(tfm_michael, key, 8))
 523                 return -1;
 524
 525         desc.tfm = tfm_michael;
 526         desc.flags = 0;
 527         return crypto_hash_digest(&desc, sg, data_len + 16, mic);
 528 }
 529
 530 static void michael_mic_hdr(struct sk_buff *skb, u8 * hdr)
 531 {
 532         struct ieee80211_hdr *hdr11;
 533
 534         hdr11 = (struct ieee80211_hdr *)skb->data;
 535
 536         switch (le16_to_cpu(hdr11->frame_control) &
 537                 (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
 538         case IEEE80211_FCTL_TODS:
 539                 memcpy(hdr, hdr11->addr3, ETH_ALEN);    /* DA */
 540                 memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
 541                 break;
 542         case IEEE80211_FCTL_FROMDS:
 543                 memcpy(hdr, hdr11->addr1, ETH_ALEN);    /* DA */
 544                 memcpy(hdr + ETH_ALEN, hdr11->addr3, ETH_ALEN); /* SA */
 545                 break;
 546         case IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS:
 547                 memcpy(hdr, hdr11->addr3, ETH_ALEN);    /* DA */
 548                 memcpy(hdr + ETH_ALEN, hdr11->addr4, ETH_ALEN); /* SA */
 549                 break;
 550         case 0:
 551                 memcpy(hdr, hdr11->addr1, ETH_ALEN);    /* DA */
 552                 memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
 553                 break;
 554         }
 555
 556         if (ieee80211_is_data_qos(hdr11->frame_control)) {
 557                 hdr[12] = le16_to_cpu(*((__le16 *)ieee80211_get_qos_ctl(hdr11)))
 558                         & IEEE80211_QOS_CTL_TID_MASK;
 559         } else
 560                 hdr[12] = 0;            /* priority */
 561
 562         hdr[13] = hdr[14] = hdr[15] = 0;        /* reserved */
 563 }
 564
 565 static int lib80211_michael_mic_add(struct sk_buff *skb, int hdr_len,
 566                                      void *priv)
 567 {
 568         struct lib80211_tkip_data *tkey = priv;
 569         u8 *pos;
 570
 571         if (skb_tailroom(skb) < 8 || skb->len < hdr_len) {
 572                 printk(KERN_DEBUG "Invalid packet for Michael MIC add "
 573                        "(tailroom=%d hdr_len=%d skb->len=%d)\n",
 574                        skb_tailroom(skb), hdr_len, skb->len);
 575                 return -1;
 576         }
 577
 578         michael_mic_hdr(skb, tkey->tx_hdr);
 579         pos = skb_put(skb, 8);
 580         if (michael_mic(tkey->tx_tfm_michael, &tkey->key[16], tkey->tx_hdr,
 581                         skb->data + hdr_len, skb->len - 8 - hdr_len, pos))
 582                 return -1;
 583
 584         return 0;
 585 }
 586
 587 static void lib80211_michael_mic_failure(struct net_device *dev,
 588                                           struct ieee80211_hdr *hdr,
 589                                           int keyidx)
 590 {
 591         union iwreq_data wrqu;
 592         struct iw_michaelmicfailure ev;
 593
 594         /* TODO: needed parameters: count, keyid, key type, TSC */
 595         memset(&ev, 0, sizeof(ev));
 596         ev.flags = keyidx & IW_MICFAILURE_KEY_ID;
 597         if (hdr->addr1[0] & 0x01)
 598                 ev.flags |= IW_MICFAILURE_GROUP;
 599         else
 600                 ev.flags |= IW_MICFAILURE_PAIRWISE;
 601         ev.src_addr.sa_family = ARPHRD_ETHER;
 602         memcpy(ev.src_addr.sa_data, hdr->addr2, ETH_ALEN);
 603         memset(&wrqu, 0, sizeof(wrqu));
 604         wrqu.data.length = sizeof(ev);
 605         wireless_send_event(dev, IWEVMICHAELMICFAILURE, &wrqu, (char *)&ev);
 606 }
 607
 608 static int lib80211_michael_mic_verify(struct sk_buff *skb, int keyidx,
 609                                         int hdr_len, void *priv)
 610 {
 611         struct lib80211_tkip_data *tkey = priv;
 612         u8 mic[8];
 613
 614         if (!tkey->key_set)
 615                 return -1;
 616
 617         michael_mic_hdr(skb, tkey->rx_hdr);
 618         if (michael_mic(tkey->rx_tfm_michael, &tkey->key[24], tkey->rx_hdr,
 619                         skb->data + hdr_len, skb->len - 8 - hdr_len, mic))
 620                 return -1;
 621         if (memcmp(mic, skb->data + skb->len - 8, 8) != 0) {
 622                 struct ieee80211_hdr *hdr;
 623                 hdr = (struct ieee80211_hdr *)skb->data;
 624                 printk(KERN_DEBUG "%s: Michael MIC verification failed for "
 625                        "MSDU from %pM keyidx=%d\n",
 626                        skb->dev ? skb->dev->name : "N/A", hdr->addr2,
 627                        keyidx);
 628                 if (skb->dev)
 629                         lib80211_michael_mic_failure(skb->dev, hdr, keyidx);
 630                 tkey->dot11RSNAStatsTKIPLocalMICFailures++;
 631                 return -1;
 632         }
 633
 634         /* Update TSC counters for RX now that the packet verification has
 635          * completed. */
 636         tkey->rx_iv32 = tkey->rx_iv32_new;
 637         tkey->rx_iv16 = tkey->rx_iv16_new;
 638
 639         skb_trim(skb, skb->len - 8);
 640
 641         return 0;
 642 }
 643
 644 static int lib80211_tkip_set_key(void *key, int len, u8 * seq, void *priv)
 645 {
 646         struct lib80211_tkip_data *tkey = priv;
 647         int keyidx;
 648         struct crypto_hash *tfm = tkey->tx_tfm_michael;
 649         struct crypto_blkcipher *tfm2 = tkey->tx_tfm_arc4;
 650         struct crypto_hash *tfm3 = tkey->rx_tfm_michael;
 651         struct crypto_blkcipher *tfm4 = tkey->rx_tfm_arc4;
 652
 653         keyidx = tkey->key_idx;
 654         memset(tkey, 0, sizeof(*tkey));
 655         tkey->key_idx = keyidx;
 656         tkey->tx_tfm_michael = tfm;
 657         tkey->tx_tfm_arc4 = tfm2;
 658         tkey->rx_tfm_michael = tfm3;
 659         tkey->rx_tfm_arc4 = tfm4;
 660         if (len == TKIP_KEY_LEN) {
 661                 memcpy(tkey->key, key, TKIP_KEY_LEN);
 662                 tkey->key_set = 1;
 663                 tkey->tx_iv16 = 1;      /* TSC is initialized to 1 */
 664                 if (seq) {
 665                         tkey->rx_iv32 = (seq[5] << 24) | (seq[4] << 16) |
 666                             (seq[3] << 8) | seq[2];
 667                         tkey->rx_iv16 = (seq[1] << 8) | seq[0];
 668                 }
 669         } else if (len == 0)
 670                 tkey->key_set = 0;
 671         else
 672                 return -1;
 673
 674         return 0;
 675 }
 676
 677 static int lib80211_tkip_get_key(void *key, int len, u8 * seq, void *priv)
 678 {
 679         struct lib80211_tkip_data *tkey = priv;
 680
 681         if (len < TKIP_KEY_LEN)
 682                 return -1;
 683
 684         if (!tkey->key_set)
 685                 return 0;
 686         memcpy(key, tkey->key, TKIP_KEY_LEN);
 687
 688         if (seq) {
 689                 /* Return the sequence number of the last transmitted frame. */
 690                 u16 iv16 = tkey->tx_iv16;
 691                 u32 iv32 = tkey->tx_iv32;
 692                 if (iv16 == 0)
 693                         iv32--;
 694                 iv16--;
 695                 seq[0] = tkey->tx_iv16;
 696                 seq[1] = tkey->tx_iv16 >> 8;
 697                 seq[2] = tkey->tx_iv32;
 698                 seq[3] = tkey->tx_iv32 >> 8;
 699                 seq[4] = tkey->tx_iv32 >> 16;
 700                 seq[5] = tkey->tx_iv32 >> 24;
 701         }
 702
 703         return TKIP_KEY_LEN;
 704 }
 705
 706 static void lib80211_tkip_print_stats(struct seq_file *m, void *priv)
 707 {
 708         struct lib80211_tkip_data *tkip = priv;
 709         seq_printf(m,
 710                    "key[%d] alg=TKIP key_set=%d "
 711                    "tx_pn=%02x%02x%02x%02x%02x%02x "
 712                    "rx_pn=%02x%02x%02x%02x%02x%02x "
 713                    "replays=%d icv_errors=%d local_mic_failures=%d\n",
 714                    tkip->key_idx, tkip->key_set,
 715                    (tkip->tx_iv32 >> 24) & 0xff,
 716                    (tkip->tx_iv32 >> 16) & 0xff,
 717                    (tkip->tx_iv32 >> 8) & 0xff,
 718                    tkip->tx_iv32 & 0xff,
 719                    (tkip->tx_iv16 >> 8) & 0xff,
 720                    tkip->tx_iv16 & 0xff,
 721                    (tkip->rx_iv32 >> 24) & 0xff,
 722                    (tkip->rx_iv32 >> 16) & 0xff,
 723                    (tkip->rx_iv32 >> 8) & 0xff,
 724                    tkip->rx_iv32 & 0xff,
 725                    (tkip->rx_iv16 >> 8) & 0xff,
 726                    tkip->rx_iv16 & 0xff,
 727                    tkip->dot11RSNAStatsTKIPReplays,
 728                    tkip->dot11RSNAStatsTKIPICVErrors,
 729                    tkip->dot11RSNAStatsTKIPLocalMICFailures);
 730 }
 731
 732 static struct lib80211_crypto_ops lib80211_crypt_tkip = {
 733         .name = "TKIP",
 734         .init = lib80211_tkip_init,
 735         .deinit = lib80211_tkip_deinit,
 736         .encrypt_mpdu = lib80211_tkip_encrypt,
 737         .decrypt_mpdu = lib80211_tkip_decrypt,
 738         .encrypt_msdu = lib80211_michael_mic_add,
 739         .decrypt_msdu = lib80211_michael_mic_verify,
 740         .set_key = lib80211_tkip_set_key,
 741         .get_key = lib80211_tkip_get_key,
 742         .print_stats = lib80211_tkip_print_stats,
 743         .extra_mpdu_prefix_len = 4 + 4, /* IV + ExtIV */
 744         .extra_mpdu_postfix_len = 4,    /* ICV */
 745         .extra_msdu_postfix_len = 8,    /* MIC */
 746         .get_flags = lib80211_tkip_get_flags,
 747         .set_flags = lib80211_tkip_set_flags,
 748         .owner = THIS_MODULE,
 749 };
 750
 751 static int __init lib80211_crypto_tkip_init(void)
 752 {
 753         return lib80211_register_crypto_ops(&lib80211_crypt_tkip);
 754 }
 755
 756 static void __exit lib80211_crypto_tkip_exit(void)
 757 {
 758         lib80211_unregister_crypto_ops(&lib80211_crypt_tkip);
 759 }
 760
 761 module_init(lib80211_crypto_tkip_init);
 762 module_exit(lib80211_crypto_tkip_exit);