net/ieee80211/ieee80211_crypt_tkip.c

   1 /*
   2  * Host AP crypt: host-based TKIP encryption implementation for Host AP driver
   3  *
   4  * Copyright (c) 2003-2004, Jouni Malinen <j@w1.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/err.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 <linux/netdevice.h>
  19 #include <linux/mm.h>
  20 #include <linux/if_ether.h>
  21 #include <linux/if_arp.h>
  22 #include <asm/string.h>
  23
  24 #include <net/ieee80211.h>
  25
  26 #include <linux/crypto.h>
  27 #include <asm/scatterlist.h>
  28 #include <linux/crc32.h>
  29
  30 MODULE_AUTHOR("Jouni Malinen");
  31 MODULE_DESCRIPTION("Host AP crypt: TKIP");
  32 MODULE_LICENSE("GPL");
  33
  34 struct ieee80211_tkip_data {
  35 #define TKIP_KEY_LEN 32
  36         u8 key[TKIP_KEY_LEN];
  37         int key_set;
  38
  39         u32 tx_iv32;
  40         u16 tx_iv16;
  41         u16 tx_ttak[5];
  42         int tx_phase1_done;
  43
  44         u32 rx_iv32;
  45         u16 rx_iv16;
  46         u16 rx_ttak[5];
  47         int rx_phase1_done;
  48         u32 rx_iv32_new;
  49         u16 rx_iv16_new;
  50
  51         u32 dot11RSNAStatsTKIPReplays;
  52         u32 dot11RSNAStatsTKIPICVErrors;
  53         u32 dot11RSNAStatsTKIPLocalMICFailures;
  54
  55         int key_idx;
  56
  57         struct crypto_blkcipher *rx_tfm_arc4;
  58         struct crypto_hash *rx_tfm_michael;
  59         struct crypto_blkcipher *tx_tfm_arc4;
  60         struct crypto_hash *tx_tfm_michael;
  61
  62         /* scratch buffers for virt_to_page() (crypto API) */
  63         u8 rx_hdr[16], tx_hdr[16];
  64
  65         unsigned long flags;
  66 };
  67
  68 static unsigned long ieee80211_tkip_set_flags(unsigned long flags, void *priv)
  69 {
  70         struct ieee80211_tkip_data *_priv = priv;
  71         unsigned long old_flags = _priv->flags;
  72         _priv->flags = flags;
  73         return old_flags;
  74 }
  75
  76 static unsigned long ieee80211_tkip_get_flags(void *priv)
  77 {
  78         struct ieee80211_tkip_data *_priv = priv;
  79         return _priv->flags;
  80 }
  81
  82 static void *ieee80211_tkip_init(int key_idx)
  83 {
  84         struct ieee80211_tkip_data *priv;
  85
  86         priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
  87         if (priv == NULL)
  88                 goto fail;
  89
  90         priv->key_idx = key_idx;
  91
  92         priv->tx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,
  93                                                 CRYPTO_ALG_ASYNC);
  94         if (IS_ERR(priv->tx_tfm_arc4)) {
  95                 printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
  96                        "crypto API arc4\n");
  97                 priv->tx_tfm_arc4 = NULL;
  98                 goto fail;
  99         }
 100
 101         priv->tx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
 102                                                  CRYPTO_ALG_ASYNC);
 103         if (IS_ERR(priv->tx_tfm_michael)) {
 104                 printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
 105                        "crypto API michael_mic\n");
 106                 priv->tx_tfm_michael = NULL;
 107                 goto fail;
 108         }
 109
 110         priv->rx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,
 111                                                 CRYPTO_ALG_ASYNC);
 112         if (IS_ERR(priv->rx_tfm_arc4)) {
 113                 printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
 114                        "crypto API arc4\n");
 115                 priv->rx_tfm_arc4 = NULL;
 116                 goto fail;
 117         }
 118
 119         priv->rx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
 120                                                  CRYPTO_ALG_ASYNC);
 121         if (IS_ERR(priv->rx_tfm_michael)) {
 122                 printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
 123                        "crypto API michael_mic\n");
 124                 priv->rx_tfm_michael = NULL;
 125                 goto fail;
 126         }
 127
 128         return priv;
 129
 130       fail:
 131         if (priv) {
 132                 if (priv->tx_tfm_michael)
 133                         crypto_free_hash(priv->tx_tfm_michael);
 134                 if (priv->tx_tfm_arc4)
 135                         crypto_free_blkcipher(priv->tx_tfm_arc4);
 136                 if (priv->rx_tfm_michael)
 137                         crypto_free_hash(priv->rx_tfm_michael);
 138                 if (priv->rx_tfm_arc4)
 139                         crypto_free_blkcipher(priv->rx_tfm_arc4);
 140                 kfree(priv);
 141         }
 142
 143         return NULL;
 144 }
 145
 146 static void ieee80211_tkip_deinit(void *priv)
 147 {
 148         struct ieee80211_tkip_data *_priv = priv;
 149         if (_priv) {
 150                 if (_priv->tx_tfm_michael)
 151                         crypto_free_hash(_priv->tx_tfm_michael);
 152                 if (_priv->tx_tfm_arc4)
 153                         crypto_free_blkcipher(_priv->tx_tfm_arc4);
 154                 if (_priv->rx_tfm_michael)
 155                         crypto_free_hash(_priv->rx_tfm_michael);
 156                 if (_priv->rx_tfm_arc4)
 157                         crypto_free_blkcipher(_priv->rx_tfm_arc4);
 158         }
 159         kfree(priv);
 160 }
 161
 162 static inline u16 RotR1(u16 val)
 163 {
 164         return (val >> 1) | (val << 15);
 165 }
 166
 167 static inline u8 Lo8(u16 val)
 168 {
 169         return val & 0xff;
 170 }
 171
 172 static inline u8 Hi8(u16 val)
 173 {
 174         return val >> 8;
 175 }
 176
 177 static inline u16 Lo16(u32 val)
 178 {
 179         return val & 0xffff;
 180 }
 181
 182 static inline u16 Hi16(u32 val)
 183 {
 184         return val >> 16;
 185 }
 186
 187 static inline u16 Mk16(u8 hi, u8 lo)
 188 {
 189         return lo | (((u16) hi) << 8);
 190 }
 191
 192 static inline u16 Mk16_le(u16 * v)
 193 {
 194         return le16_to_cpu(*v);
 195 }
 196
 197 static const u16 Sbox[256] = {
 198         0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
 199         0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
 200         0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
 201         0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
 202         0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
 203         0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
 204         0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
 205         0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
 206         0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
 207         0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
 208         0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
 209         0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
 210         0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
 211         0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
 212         0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
 213         0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
 214         0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
 215         0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
 216         0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
 217         0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
 218         0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
 219         0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
 220         0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
 221         0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
 222         0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
 223         0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
 224         0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
 225         0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
 226         0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
 227         0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
 228         0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
 229         0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
 230 };
 231
 232 static inline u16 _S_(u16 v)
 233 {
 234         u16 t = Sbox[Hi8(v)];
 235         return Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8));
 236 }
 237
 238 #define PHASE1_LOOP_COUNT 8
 239
 240 static void tkip_mixing_phase1(u16 * TTAK, const u8 * TK, const u8 * TA,
 241                                u32 IV32)
 242 {
 243         int i, j;
 244
 245         /* Initialize the 80-bit TTAK from TSC (IV32) and TA[0..5] */
 246         TTAK[0] = Lo16(IV32);
 247         TTAK[1] = Hi16(IV32);
 248         TTAK[2] = Mk16(TA[1], TA[0]);
 249         TTAK[3] = Mk16(TA[3], TA[2]);
 250         TTAK[4] = Mk16(TA[5], TA[4]);
 251
 252         for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
 253                 j = 2 * (i & 1);
 254                 TTAK[0] += _S_(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]));
 255                 TTAK[1] += _S_(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]));
 256                 TTAK[2] += _S_(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]));
 257                 TTAK[3] += _S_(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]));
 258                 TTAK[4] += _S_(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j])) + i;
 259         }
 260 }
 261
 262 static void tkip_mixing_phase2(u8 * WEPSeed, const u8 * TK, const u16 * TTAK,
 263                                u16 IV16)
 264 {
 265         /* Make temporary area overlap WEP seed so that the final copy can be
 266          * avoided on little endian hosts. */
 267         u16 *PPK = (u16 *) & WEPSeed[4];
 268
 269         /* Step 1 - make copy of TTAK and bring in TSC */
 270         PPK[0] = TTAK[0];
 271         PPK[1] = TTAK[1];
 272         PPK[2] = TTAK[2];
 273         PPK[3] = TTAK[3];
 274         PPK[4] = TTAK[4];
 275         PPK[5] = TTAK[4] + IV16;
 276
 277         /* Step 2 - 96-bit bijective mixing using S-box */
 278         PPK[0] += _S_(PPK[5] ^ Mk16_le((u16 *) & TK[0]));
 279         PPK[1] += _S_(PPK[0] ^ Mk16_le((u16 *) & TK[2]));
 280         PPK[2] += _S_(PPK[1] ^ Mk16_le((u16 *) & TK[4]));
 281         PPK[3] += _S_(PPK[2] ^ Mk16_le((u16 *) & TK[6]));
 282         PPK[4] += _S_(PPK[3] ^ Mk16_le((u16 *) & TK[8]));
 283         PPK[5] += _S_(PPK[4] ^ Mk16_le((u16 *) & TK[10]));
 284
 285         PPK[0] += RotR1(PPK[5] ^ Mk16_le((u16 *) & TK[12]));
 286         PPK[1] += RotR1(PPK[0] ^ Mk16_le((u16 *) & TK[14]));
 287         PPK[2] += RotR1(PPK[1]);
 288         PPK[3] += RotR1(PPK[2]);
 289         PPK[4] += RotR1(PPK[3]);
 290         PPK[5] += RotR1(PPK[4]);
 291
 292         /* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
 293          * WEPSeed[0..2] is transmitted as WEP IV */
 294         WEPSeed[0] = Hi8(IV16);
 295         WEPSeed[1] = (Hi8(IV16) | 0x20) & 0x7F;
 296         WEPSeed[2] = Lo8(IV16);
 297         WEPSeed[3] = Lo8((PPK[5] ^ Mk16_le((u16 *) & TK[0])) >> 1);
 298
 299 #ifdef __BIG_ENDIAN
 300         {
 301                 int i;
 302                 for (i = 0; i < 6; i++)
 303                         PPK[i] = (PPK[i] << 8) | (PPK[i] >> 8);
 304         }
 305 #endif
 306 }
 307
 308 static int ieee80211_tkip_hdr(struct sk_buff *skb, int hdr_len,
 309                               u8 * rc4key, int keylen, void *priv)
 310 {
 311         struct ieee80211_tkip_data *tkey = priv;
 312         int len;
 313         u8 *pos;
 314         struct ieee80211_hdr_4addr *hdr;
 315
 316         hdr = (struct ieee80211_hdr_4addr *)skb->data;
 317
 318         if (skb_headroom(skb) < 8 || 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         len = skb->len - hdr_len;
 332         pos = skb_push(skb, 8);
 333         memmove(pos, pos + 8, hdr_len);
 334         pos += hdr_len;
 335
 336         *pos++ = *rc4key;
 337         *pos++ = *(rc4key + 1);
 338         *pos++ = *(rc4key + 2);
 339         *pos++ = (tkey->key_idx << 6) | (1 << 5) /* Ext IV included */ ;
 340         *pos++ = tkey->tx_iv32 & 0xff;
 341         *pos++ = (tkey->tx_iv32 >> 8) & 0xff;
 342         *pos++ = (tkey->tx_iv32 >> 16) & 0xff;
 343         *pos++ = (tkey->tx_iv32 >> 24) & 0xff;
 344
 345         tkey->tx_iv16++;
 346         if (tkey->tx_iv16 == 0) {
 347                 tkey->tx_phase1_done = 0;
 348                 tkey->tx_iv32++;
 349         }
 350
 351         return 8;
 352 }
 353
 354 static int ieee80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 355 {
 356         struct ieee80211_tkip_data *tkey = priv;
 357         struct blkcipher_desc desc = { .tfm = tkey->tx_tfm_arc4 };
 358         int len;
 359         u8 rc4key[16], *pos, *icv;
 360         u32 crc;
 361         struct scatterlist sg;
 362
 363         if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
 364                 if (net_ratelimit()) {
 365                         struct ieee80211_hdr_4addr *hdr =
 366                             (struct ieee80211_hdr_4addr *)skb->data;
 367                         printk(KERN_DEBUG ": TKIP countermeasures: dropped "
 368                                "TX packet to " MAC_FMT "\n",
 369                                MAC_ARG(hdr->addr1));
 370                 }
 371                 return -1;
 372         }
 373
 374         if (skb_tailroom(skb) < 4 || skb->len < hdr_len)
 375                 return -1;
 376
 377         len = skb->len - hdr_len;
 378         pos = skb->data + hdr_len;
 379
 380         if ((ieee80211_tkip_hdr(skb, hdr_len, rc4key, 16, priv)) < 0)
 381                 return -1;
 382
 383         icv = skb_put(skb, 4);
 384
 385         crc = ~crc32_le(~0, pos, len);
 386         icv[0] = crc;
 387         icv[1] = crc >> 8;
 388         icv[2] = crc >> 16;
 389         icv[3] = crc >> 24;
 390
 391         crypto_blkcipher_setkey(tkey->tx_tfm_arc4, rc4key, 16);
 392         sg.page = virt_to_page(pos);
 393         sg.offset = offset_in_page(pos);
 394         sg.length = len + 4;
 395         return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
 396 }
 397
 398 /*
 399  * deal with seq counter wrapping correctly.
 400  * refer to timer_after() for jiffies wrapping handling
 401  */
 402 static inline int tkip_replay_check(u32 iv32_n, u16 iv16_n,
 403                                     u32 iv32_o, u16 iv16_o)
 404 {
 405         if ((s32)iv32_n - (s32)iv32_o < 0 ||
 406             (iv32_n == iv32_o && iv16_n <= iv16_o))
 407                 return 1;
 408         return 0;
 409 }
 410
 411 static int ieee80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 412 {
 413         struct ieee80211_tkip_data *tkey = priv;
 414         struct blkcipher_desc desc = { .tfm = tkey->rx_tfm_arc4 };
 415         u8 rc4key[16];
 416         u8 keyidx, *pos;
 417         u32 iv32;
 418         u16 iv16;
 419         struct ieee80211_hdr_4addr *hdr;
 420         u8 icv[4];
 421         u32 crc;
 422         struct scatterlist sg;
 423         int plen;
 424
 425         hdr = (struct ieee80211_hdr_4addr *)skb->data;
 426
 427         if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
 428                 if (net_ratelimit()) {
 429                         printk(KERN_DEBUG ": TKIP countermeasures: dropped "
 430                                "received packet from " MAC_FMT "\n",
 431                                MAC_ARG(hdr->addr2));
 432                 }
 433                 return -1;
 434         }
 435
 436         if (skb->len < hdr_len + 8 + 4)
 437                 return -1;
 438
 439         pos = skb->data + hdr_len;
 440         keyidx = pos[3];
 441         if (!(keyidx & (1 << 5))) {
 442                 if (net_ratelimit()) {
 443                         printk(KERN_DEBUG "TKIP: received packet without ExtIV"
 444                                " flag from " MAC_FMT "\n", MAC_ARG(hdr->addr2));
 445                 }
 446                 return -2;
 447         }
 448         keyidx >>= 6;
 449         if (tkey->key_idx != keyidx) {
 450                 printk(KERN_DEBUG "TKIP: RX tkey->key_idx=%d frame "
 451                        "keyidx=%d priv=%p\n", tkey->key_idx, keyidx, priv);
 452                 return -6;
 453         }
 454         if (!tkey->key_set) {
 455                 if (net_ratelimit()) {
 456                         printk(KERN_DEBUG "TKIP: received packet from " MAC_FMT
 457                                " with keyid=%d that does not have a configured"
 458                                " key\n", MAC_ARG(hdr->addr2), keyidx);
 459                 }
 460                 return -3;
 461         }
 462         iv16 = (pos[0] << 8) | pos[2];
 463         iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24);
 464         pos += 8;
 465
 466         if (tkip_replay_check(iv32, iv16, tkey->rx_iv32, tkey->rx_iv16)) {
 467                 if (net_ratelimit()) {
 468                         IEEE80211_DEBUG_DROP("TKIP: replay detected: STA=" MAC_FMT
 469                                " previous TSC %08x%04x received TSC "
 470                                "%08x%04x\n", MAC_ARG(hdr->addr2),
 471                                tkey->rx_iv32, tkey->rx_iv16, iv32, iv16);
 472                 }
 473                 tkey->dot11RSNAStatsTKIPReplays++;
 474                 return -4;
 475         }
 476
 477         if (iv32 != tkey->rx_iv32 || !tkey->rx_phase1_done) {
 478                 tkip_mixing_phase1(tkey->rx_ttak, tkey->key, hdr->addr2, iv32);
 479                 tkey->rx_phase1_done = 1;
 480         }
 481         tkip_mixing_phase2(rc4key, tkey->key, tkey->rx_ttak, iv16);
 482
 483         plen = skb->len - hdr_len - 12;
 484
 485         crypto_blkcipher_setkey(tkey->rx_tfm_arc4, rc4key, 16);
 486         sg.page = virt_to_page(pos);
 487         sg.offset = offset_in_page(pos);
 488         sg.length = plen + 4;
 489         if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4)) {
 490                 if (net_ratelimit()) {
 491                         printk(KERN_DEBUG ": TKIP: failed to decrypt "
 492                                "received packet from " MAC_FMT "\n",
 493                                MAC_ARG(hdr->addr2));
 494                 }
 495                 return -7;
 496         }
 497
 498         crc = ~crc32_le(~0, pos, plen);
 499         icv[0] = crc;
 500         icv[1] = crc >> 8;
 501         icv[2] = crc >> 16;
 502         icv[3] = crc >> 24;
 503         if (memcmp(icv, pos + plen, 4) != 0) {
 504                 if (iv32 != tkey->rx_iv32) {
 505                         /* Previously cached Phase1 result was already lost, so
 506                          * it needs to be recalculated for the next packet. */
 507                         tkey->rx_phase1_done = 0;
 508                 }
 509                 if (net_ratelimit()) {
 510                         IEEE80211_DEBUG_DROP("TKIP: ICV error detected: STA="
 511                                MAC_FMT "\n", MAC_ARG(hdr->addr2));
 512                 }
 513                 tkey->dot11RSNAStatsTKIPICVErrors++;
 514                 return -5;
 515         }
 516
 517         /* Update real counters only after Michael MIC verification has
 518          * completed */
 519         tkey->rx_iv32_new = iv32;
 520         tkey->rx_iv16_new = iv16;
 521
 522         /* Remove IV and ICV */
 523         memmove(skb->data + 8, skb->data, hdr_len);
 524         skb_pull(skb, 8);
 525         skb_trim(skb, skb->len - 4);
 526
 527         return keyidx;
 528 }
 529
 530 static int michael_mic(struct crypto_hash *tfm_michael, u8 * key, u8 * hdr,
 531                        u8 * data, size_t data_len, u8 * mic)
 532 {
 533         struct hash_desc desc;
 534         struct scatterlist sg[2];
 535
 536         if (tfm_michael == NULL) {
 537                 printk(KERN_WARNING "michael_mic: tfm_michael == NULL\n");
 538                 return -1;
 539         }
 540         sg[0].page = virt_to_page(hdr);
 541         sg[0].offset = offset_in_page(hdr);
 542         sg[0].length = 16;
 543
 544         sg[1].page = virt_to_page(data);
 545         sg[1].offset = offset_in_page(data);
 546         sg[1].length = data_len;
 547
 548         if (crypto_hash_setkey(tfm_michael, key, 8))
 549                 return -1;
 550
 551         desc.tfm = tfm_michael;
 552         desc.flags = 0;
 553         return crypto_hash_digest(&desc, sg, data_len + 16, mic);
 554 }
 555
 556 static void michael_mic_hdr(struct sk_buff *skb, u8 * hdr)
 557 {
 558         struct ieee80211_hdr_4addr *hdr11;
 559         u16 stype;
 560
 561         hdr11 = (struct ieee80211_hdr_4addr *)skb->data;
 562         stype  = WLAN_FC_GET_STYPE(le16_to_cpu(hdr11->frame_ctl));
 563
 564         switch (le16_to_cpu(hdr11->frame_ctl) &
 565                 (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
 566         case IEEE80211_FCTL_TODS:
 567                 memcpy(hdr, hdr11->addr3, ETH_ALEN);    /* DA */
 568                 memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
 569                 break;
 570         case IEEE80211_FCTL_FROMDS:
 571                 memcpy(hdr, hdr11->addr1, ETH_ALEN);    /* DA */
 572                 memcpy(hdr + ETH_ALEN, hdr11->addr3, ETH_ALEN); /* SA */
 573                 break;
 574         case IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS:
 575                 memcpy(hdr, hdr11->addr3, ETH_ALEN);    /* DA */
 576                 memcpy(hdr + ETH_ALEN, hdr11->addr4, ETH_ALEN); /* SA */
 577                 break;
 578         case 0:
 579                 memcpy(hdr, hdr11->addr1, ETH_ALEN);    /* DA */
 580                 memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
 581                 break;
 582         }
 583
 584         if (stype & IEEE80211_STYPE_QOS_DATA) {
 585                 const struct ieee80211_hdr_3addrqos *qoshdr =
 586                         (struct ieee80211_hdr_3addrqos *)skb->data;
 587                 hdr[12] = qoshdr->qos_ctl & cpu_to_le16(IEEE80211_QCTL_TID);
 588         } else
 589                 hdr[12] = 0;            /* priority */
 590
 591         hdr[13] = hdr[14] = hdr[15] = 0;        /* reserved */
 592 }
 593
 594 static int ieee80211_michael_mic_add(struct sk_buff *skb, int hdr_len,
 595                                      void *priv)
 596 {
 597         struct ieee80211_tkip_data *tkey = priv;
 598         u8 *pos;
 599
 600         if (skb_tailroom(skb) < 8 || skb->len < hdr_len) {
 601                 printk(KERN_DEBUG "Invalid packet for Michael MIC add "
 602                        "(tailroom=%d hdr_len=%d skb->len=%d)\n",
 603                        skb_tailroom(skb), hdr_len, skb->len);
 604                 return -1;
 605         }
 606
 607         michael_mic_hdr(skb, tkey->tx_hdr);
 608         pos = skb_put(skb, 8);
 609         if (michael_mic(tkey->tx_tfm_michael, &tkey->key[16], tkey->tx_hdr,
 610                         skb->data + hdr_len, skb->len - 8 - hdr_len, pos))
 611                 return -1;
 612
 613         return 0;
 614 }
 615
 616 static void ieee80211_michael_mic_failure(struct net_device *dev,
 617                                           struct ieee80211_hdr_4addr *hdr,
 618                                           int keyidx)
 619 {
 620         union iwreq_data wrqu;
 621         struct iw_michaelmicfailure ev;
 622
 623         /* TODO: needed parameters: count, keyid, key type, TSC */
 624         memset(&ev, 0, sizeof(ev));
 625         ev.flags = keyidx & IW_MICFAILURE_KEY_ID;
 626         if (hdr->addr1[0] & 0x01)
 627                 ev.flags |= IW_MICFAILURE_GROUP;
 628         else
 629                 ev.flags |= IW_MICFAILURE_PAIRWISE;
 630         ev.src_addr.sa_family = ARPHRD_ETHER;
 631         memcpy(ev.src_addr.sa_data, hdr->addr2, ETH_ALEN);
 632         memset(&wrqu, 0, sizeof(wrqu));
 633         wrqu.data.length = sizeof(ev);
 634         wireless_send_event(dev, IWEVMICHAELMICFAILURE, &wrqu, (char *)&ev);
 635 }
 636
 637 static int ieee80211_michael_mic_verify(struct sk_buff *skb, int keyidx,
 638                                         int hdr_len, void *priv)
 639 {
 640         struct ieee80211_tkip_data *tkey = priv;
 641         u8 mic[8];
 642
 643         if (!tkey->key_set)
 644                 return -1;
 645
 646         michael_mic_hdr(skb, tkey->rx_hdr);
 647         if (michael_mic(tkey->rx_tfm_michael, &tkey->key[24], tkey->rx_hdr,
 648                         skb->data + hdr_len, skb->len - 8 - hdr_len, mic))
 649                 return -1;
 650         if (memcmp(mic, skb->data + skb->len - 8, 8) != 0) {
 651                 struct ieee80211_hdr_4addr *hdr;
 652                 hdr = (struct ieee80211_hdr_4addr *)skb->data;
 653                 printk(KERN_DEBUG "%s: Michael MIC verification failed for "
 654                        "MSDU from " MAC_FMT " keyidx=%d\n",
 655                        skb->dev ? skb->dev->name : "N/A", MAC_ARG(hdr->addr2),
 656                        keyidx);
 657                 if (skb->dev)
 658                         ieee80211_michael_mic_failure(skb->dev, hdr, keyidx);
 659                 tkey->dot11RSNAStatsTKIPLocalMICFailures++;
 660                 return -1;
 661         }
 662
 663         /* Update TSC counters for RX now that the packet verification has
 664          * completed. */
 665         tkey->rx_iv32 = tkey->rx_iv32_new;
 666         tkey->rx_iv16 = tkey->rx_iv16_new;
 667
 668         skb_trim(skb, skb->len - 8);
 669
 670         return 0;
 671 }
 672
 673 static int ieee80211_tkip_set_key(void *key, int len, u8 * seq, void *priv)
 674 {
 675         struct ieee80211_tkip_data *tkey = priv;
 676         int keyidx;
 677         struct crypto_hash *tfm = tkey->tx_tfm_michael;
 678         struct crypto_blkcipher *tfm2 = tkey->tx_tfm_arc4;
 679         struct crypto_hash *tfm3 = tkey->rx_tfm_michael;
 680         struct crypto_blkcipher *tfm4 = tkey->rx_tfm_arc4;
 681
 682         keyidx = tkey->key_idx;
 683         memset(tkey, 0, sizeof(*tkey));
 684         tkey->key_idx = keyidx;
 685         tkey->tx_tfm_michael = tfm;
 686         tkey->tx_tfm_arc4 = tfm2;
 687         tkey->rx_tfm_michael = tfm3;
 688         tkey->rx_tfm_arc4 = tfm4;
 689         if (len == TKIP_KEY_LEN) {
 690                 memcpy(tkey->key, key, TKIP_KEY_LEN);
 691                 tkey->key_set = 1;
 692                 tkey->tx_iv16 = 1;      /* TSC is initialized to 1 */
 693                 if (seq) {
 694                         tkey->rx_iv32 = (seq[5] << 24) | (seq[4] << 16) |
 695                             (seq[3] << 8) | seq[2];
 696                         tkey->rx_iv16 = (seq[1] << 8) | seq[0];
 697                 }
 698         } else if (len == 0)
 699                 tkey->key_set = 0;
 700         else
 701                 return -1;
 702
 703         return 0;
 704 }
 705
 706 static int ieee80211_tkip_get_key(void *key, int len, u8 * seq, void *priv)
 707 {
 708         struct ieee80211_tkip_data *tkey = priv;
 709
 710         if (len < TKIP_KEY_LEN)
 711                 return -1;
 712
 713         if (!tkey->key_set)
 714                 return 0;
 715         memcpy(key, tkey->key, TKIP_KEY_LEN);
 716
 717         if (seq) {
 718                 /* Return the sequence number of the last transmitted frame. */
 719                 u16 iv16 = tkey->tx_iv16;
 720                 u32 iv32 = tkey->tx_iv32;
 721                 if (iv16 == 0)
 722                         iv32--;
 723                 iv16--;
 724                 seq[0] = tkey->tx_iv16;
 725                 seq[1] = tkey->tx_iv16 >> 8;
 726                 seq[2] = tkey->tx_iv32;
 727                 seq[3] = tkey->tx_iv32 >> 8;
 728                 seq[4] = tkey->tx_iv32 >> 16;
 729                 seq[5] = tkey->tx_iv32 >> 24;
 730         }
 731
 732         return TKIP_KEY_LEN;
 733 }
 734
 735 static char *ieee80211_tkip_print_stats(char *p, void *priv)
 736 {
 737         struct ieee80211_tkip_data *tkip = priv;
 738         p += sprintf(p, "key[%d] alg=TKIP key_set=%d "
 739                      "tx_pn=%02x%02x%02x%02x%02x%02x "
 740                      "rx_pn=%02x%02x%02x%02x%02x%02x "
 741                      "replays=%d icv_errors=%d local_mic_failures=%d\n",
 742                      tkip->key_idx, tkip->key_set,
 743                      (tkip->tx_iv32 >> 24) & 0xff,
 744                      (tkip->tx_iv32 >> 16) & 0xff,
 745                      (tkip->tx_iv32 >> 8) & 0xff,
 746                      tkip->tx_iv32 & 0xff,
 747                      (tkip->tx_iv16 >> 8) & 0xff,
 748                      tkip->tx_iv16 & 0xff,
 749                      (tkip->rx_iv32 >> 24) & 0xff,
 750                      (tkip->rx_iv32 >> 16) & 0xff,
 751                      (tkip->rx_iv32 >> 8) & 0xff,
 752                      tkip->rx_iv32 & 0xff,
 753                      (tkip->rx_iv16 >> 8) & 0xff,
 754                      tkip->rx_iv16 & 0xff,
 755                      tkip->dot11RSNAStatsTKIPReplays,
 756                      tkip->dot11RSNAStatsTKIPICVErrors,
 757                      tkip->dot11RSNAStatsTKIPLocalMICFailures);
 758         return p;
 759 }
 760
 761 static struct ieee80211_crypto_ops ieee80211_crypt_tkip = {
 762         .name = "TKIP",
 763         .init = ieee80211_tkip_init,
 764         .deinit = ieee80211_tkip_deinit,
 765         .build_iv = ieee80211_tkip_hdr,
 766         .encrypt_mpdu = ieee80211_tkip_encrypt,
 767         .decrypt_mpdu = ieee80211_tkip_decrypt,
 768         .encrypt_msdu = ieee80211_michael_mic_add,
 769         .decrypt_msdu = ieee80211_michael_mic_verify,
 770         .set_key = ieee80211_tkip_set_key,
 771         .get_key = ieee80211_tkip_get_key,
 772         .print_stats = ieee80211_tkip_print_stats,
 773         .extra_mpdu_prefix_len = 4 + 4, /* IV + ExtIV */
 774         .extra_mpdu_postfix_len = 4,    /* ICV */
 775         .extra_msdu_postfix_len = 8,    /* MIC */
 776         .get_flags = ieee80211_tkip_get_flags,
 777         .set_flags = ieee80211_tkip_set_flags,
 778         .owner = THIS_MODULE,
 779 };
 780
 781 static int __init ieee80211_crypto_tkip_init(void)
 782 {
 783         return ieee80211_register_crypto_ops(&ieee80211_crypt_tkip);
 784 }
 785
 786 static void __exit ieee80211_crypto_tkip_exit(void)
 787 {
 788         ieee80211_unregister_crypto_ops(&ieee80211_crypt_tkip);
 789 }
 790
 791 module_init(ieee80211_crypto_tkip_init);
 792 module_exit(ieee80211_crypto_tkip_exit);