release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/staging/rtl8192su/ieee80211/ieee80211_crypt_ccmp.c

   1 /*
   2  * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
   3  *
   4  * Copyright (c) 2003-2004, 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/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 <linux/netdevice.h>
  19 #include <linux/if_ether.h>
  20 #include <linux/if_arp.h>
  21 #include <asm/string.h>
  22 #include <linux/wireless.h>
  23
  24 #include "ieee80211.h"
  25
  26 #include <linux/crypto.h>
  27 #include <linux/scatterlist.h>
  28
  29 MODULE_AUTHOR("Jouni Malinen");
  30 MODULE_DESCRIPTION("Host AP crypt: CCMP");
  31 MODULE_LICENSE("GPL");
  32
  33 #define AES_BLOCK_LEN 16
  34 #define CCMP_HDR_LEN 8
  35 #define CCMP_MIC_LEN 8
  36 #define CCMP_TK_LEN 16
  37 #define CCMP_PN_LEN 6
  38
  39 struct ieee80211_ccmp_data {
  40         u8 key[CCMP_TK_LEN];
  41         int key_set;
  42
  43         u8 tx_pn[CCMP_PN_LEN];
  44         u8 rx_pn[CCMP_PN_LEN];
  45
  46         u32 dot11RSNAStatsCCMPFormatErrors;
  47         u32 dot11RSNAStatsCCMPReplays;
  48         u32 dot11RSNAStatsCCMPDecryptErrors;
  49
  50         int key_idx;
  51
  52         struct crypto_tfm *tfm;
  53
  54         /* scratch buffers for virt_to_page() (crypto API) */
  55         u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
  56                 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
  57         u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
  58 };
  59
  60 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
  61                              const u8 pt[16], u8 ct[16])
  62 {
  63         crypto_cipher_encrypt_one((void*)tfm, ct, pt);
  64 }
  65
  66 static void * ieee80211_ccmp_init(int key_idx)
  67 {
  68         struct ieee80211_ccmp_data *priv;
  69
  70         priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
  71         if (priv == NULL)
  72                 goto fail;
  73         priv->key_idx = key_idx;
  74
  75         priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
  76         if (IS_ERR(priv->tfm)) {
  77                 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
  78                        "crypto API aes\n");
  79                 priv->tfm = NULL;
  80                 goto fail;
  81         }
  82
  83         return priv;
  84
  85 fail:
  86         if (priv) {
  87                 if (priv->tfm)
  88                         crypto_free_cipher((void*)priv->tfm);
  89                 kfree(priv);
  90         }
  91
  92         return NULL;
  93 }
  94
  95
  96 static void ieee80211_ccmp_deinit(void *priv)
  97 {
  98         struct ieee80211_ccmp_data *_priv = priv;
  99
 100         if (_priv && _priv->tfm)
 101                 crypto_free_cipher((void*)_priv->tfm);
 102         kfree(priv);
 103 }
 104
 105
 106 static inline void xor_block(u8 *b, u8 *a, size_t len)
 107 {
 108         int i;
 109         for (i = 0; i < len; i++)
 110                 b[i] ^= a[i];
 111 }
 112
 113
 114
 115 static void ccmp_init_blocks(struct crypto_tfm *tfm,
 116                              struct ieee80211_hdr_4addr *hdr,
 117                              u8 *pn, size_t dlen, u8 *b0, u8 *auth,
 118                              u8 *s0)
 119 {
 120         u8 *pos, qc = 0;
 121         size_t aad_len;
 122         u16 fc;
 123         int a4_included, qc_included;
 124         u8 aad[2 * AES_BLOCK_LEN];
 125
 126         fc = le16_to_cpu(hdr->frame_ctl);
 127         a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 128                        (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
 129         /*
 130         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 131                        (WLAN_FC_GET_STYPE(fc) & 0x08));
 132         */
 133         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 134                        (WLAN_FC_GET_STYPE(fc) & 0x80));
 135         aad_len = 22;
 136         if (a4_included)
 137                 aad_len += 6;
 138         if (qc_included) {
 139                 pos = (u8 *) &hdr->addr4;
 140                 if (a4_included)
 141                         pos += 6;
 142                 qc = *pos & 0x0f;
 143                 aad_len += 2;
 144         }
 145         /* CCM Initial Block:
 146          * Flag (Include authentication header, M=3 (8-octet MIC),
 147          *       L=1 (2-octet Dlen))
 148          * Nonce: 0x00 | A2 | PN
 149          * Dlen */
 150         b0[0] = 0x59;
 151         b0[1] = qc;
 152         memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
 153         memcpy(b0 + 8, pn, CCMP_PN_LEN);
 154         b0[14] = (dlen >> 8) & 0xff;
 155         b0[15] = dlen & 0xff;
 156
 157         /* AAD:
 158          * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
 159          * A1 | A2 | A3
 160          * SC with bits 4..15 (seq#) masked to zero
 161          * A4 (if present)
 162          * QC (if present)
 163          */
 164         pos = (u8 *) hdr;
 165         aad[0] = 0; /* aad_len >> 8 */
 166         aad[1] = aad_len & 0xff;
 167         aad[2] = pos[0] & 0x8f;
 168         aad[3] = pos[1] & 0xc7;
 169         memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
 170         pos = (u8 *) &hdr->seq_ctl;
 171         aad[22] = pos[0] & 0x0f;
 172         aad[23] = 0; /* all bits masked */
 173         memset(aad + 24, 0, 8);
 174         if (a4_included)
 175                 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
 176         if (qc_included) {
 177                 aad[a4_included ? 30 : 24] = qc;
 178                 /* rest of QC masked */
 179         }
 180
 181         /* Start with the first block and AAD */
 182         ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
 183         xor_block(auth, aad, AES_BLOCK_LEN);
 184         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 185         xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
 186         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 187         b0[0] &= 0x07;
 188         b0[14] = b0[15] = 0;
 189         ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
 190 }
 191
 192
 193
 194 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 195 {
 196         struct ieee80211_ccmp_data *key = priv;
 197         int data_len, i;
 198         u8 *pos;
 199         struct ieee80211_hdr_4addr *hdr;
 200         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 201
 202         if (skb_headroom(skb) < CCMP_HDR_LEN ||
 203             skb_tailroom(skb) < CCMP_MIC_LEN ||
 204             skb->len < hdr_len)
 205                 return -1;
 206
 207         data_len = skb->len - hdr_len;
 208         pos = skb_push(skb, CCMP_HDR_LEN);
 209         memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
 210         pos += hdr_len;
 211
 212         i = CCMP_PN_LEN - 1;
 213         while (i >= 0) {
 214                 key->tx_pn[i]++;
 215                 if (key->tx_pn[i] != 0)
 216                         break;
 217                 i--;
 218         }
 219
 220         *pos++ = key->tx_pn[5];
 221         *pos++ = key->tx_pn[4];
 222         *pos++ = 0;
 223         *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
 224         *pos++ = key->tx_pn[3];
 225         *pos++ = key->tx_pn[2];
 226         *pos++ = key->tx_pn[1];
 227         *pos++ = key->tx_pn[0];
 228
 229
 230         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 231         if (!tcb_desc->bHwSec)
 232         {
 233                 int blocks, last, len;
 234                 u8 *mic;
 235                 u8 *b0 = key->tx_b0;
 236                 u8 *b = key->tx_b;
 237                 u8 *e = key->tx_e;
 238                 u8 *s0 = key->tx_s0;
 239
 240                 mic = skb_put(skb, CCMP_MIC_LEN);
 241
 242                 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
 243
 244                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 245                 last = data_len % AES_BLOCK_LEN;
 246
 247                 for (i = 1; i <= blocks; i++) {
 248                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 249                         /* Authentication */
 250                         xor_block(b, pos, len);
 251                         ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
 252                         /* Encryption, with counter */
 253                         b0[14] = (i >> 8) & 0xff;
 254                         b0[15] = i & 0xff;
 255                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
 256                         xor_block(pos, e, len);
 257                         pos += len;
 258                 }
 259
 260                 for (i = 0; i < CCMP_MIC_LEN; i++)
 261                         mic[i] = b[i] ^ s0[i];
 262         }
 263         return 0;
 264 }
 265
 266
 267 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 268 {
 269         struct ieee80211_ccmp_data *key = priv;
 270         u8 keyidx, *pos;
 271         struct ieee80211_hdr_4addr *hdr;
 272         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 273         u8 pn[6];
 274
 275         if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
 276                 key->dot11RSNAStatsCCMPFormatErrors++;
 277                 return -1;
 278         }
 279
 280         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 281         pos = skb->data + hdr_len;
 282         keyidx = pos[3];
 283         if (!(keyidx & (1 << 5))) {
 284                 if (net_ratelimit()) {
 285                         printk(KERN_DEBUG "CCMP: received packet without ExtIV"
 286                                " flag from %pM\n", hdr->addr2);
 287                 }
 288                 key->dot11RSNAStatsCCMPFormatErrors++;
 289                 return -2;
 290         }
 291         keyidx >>= 6;
 292         if (key->key_idx != keyidx) {
 293                 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
 294                        "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
 295                 return -6;
 296         }
 297         if (!key->key_set) {
 298                 if (net_ratelimit()) {
 299                         printk(KERN_DEBUG "CCMP: received packet from %pM"
 300                                " with keyid=%d that does not have a configured"
 301                                " key\n", hdr->addr2, keyidx);
 302                 }
 303                 return -3;
 304         }
 305
 306         pn[0] = pos[7];
 307         pn[1] = pos[6];
 308         pn[2] = pos[5];
 309         pn[3] = pos[4];
 310         pn[4] = pos[1];
 311         pn[5] = pos[0];
 312         pos += 8;
 313
 314         if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
 315                 if (net_ratelimit()) {
 316                         printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
 317                                " previous PN %pm received PN %pm\n",
 318                                hdr->addr2, key->rx_pn, pn);
 319                 }
 320                 key->dot11RSNAStatsCCMPReplays++;
 321                 return -4;
 322         }
 323         if (!tcb_desc->bHwSec)
 324         {
 325                 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
 326                 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
 327                 u8 *b0 = key->rx_b0;
 328                 u8 *b = key->rx_b;
 329                 u8 *a = key->rx_a;
 330                 int i, blocks, last, len;
 331
 332
 333                 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
 334                 xor_block(mic, b, CCMP_MIC_LEN);
 335
 336                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 337                 last = data_len % AES_BLOCK_LEN;
 338
 339                 for (i = 1; i <= blocks; i++) {
 340                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 341                         /* Decrypt, with counter */
 342                         b0[14] = (i >> 8) & 0xff;
 343                         b0[15] = i & 0xff;
 344                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
 345                         xor_block(pos, b, len);
 346                         /* Authentication */
 347                         xor_block(a, pos, len);
 348                         ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
 349                         pos += len;
 350                 }
 351
 352                 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
 353                         if (net_ratelimit()) {
 354                                 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
 355                                 "%pM\n", hdr->addr2);
 356                         }
 357                         key->dot11RSNAStatsCCMPDecryptErrors++;
 358                         return -5;
 359                 }
 360
 361                 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
 362         }
 363         /* Remove hdr and MIC */
 364         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
 365         skb_pull(skb, CCMP_HDR_LEN);
 366         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 367
 368         return keyidx;
 369 }
 370
 371
 372 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
 373 {
 374         struct ieee80211_ccmp_data *data = priv;
 375         int keyidx;
 376         struct crypto_tfm *tfm = data->tfm;
 377
 378         keyidx = data->key_idx;
 379         memset(data, 0, sizeof(*data));
 380         data->key_idx = keyidx;
 381         data->tfm = tfm;
 382         if (len == CCMP_TK_LEN) {
 383                 memcpy(data->key, key, CCMP_TK_LEN);
 384                 data->key_set = 1;
 385                 if (seq) {
 386                         data->rx_pn[0] = seq[5];
 387                         data->rx_pn[1] = seq[4];
 388                         data->rx_pn[2] = seq[3];
 389                         data->rx_pn[3] = seq[2];
 390                         data->rx_pn[4] = seq[1];
 391                         data->rx_pn[5] = seq[0];
 392                 }
 393                 crypto_cipher_setkey((void*)data->tfm, data->key, CCMP_TK_LEN);
 394         } else if (len == 0)
 395                 data->key_set = 0;
 396         else
 397                 return -1;
 398
 399         return 0;
 400 }
 401
 402
 403 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
 404 {
 405         struct ieee80211_ccmp_data *data = priv;
 406
 407         if (len < CCMP_TK_LEN)
 408                 return -1;
 409
 410         if (!data->key_set)
 411                 return 0;
 412         memcpy(key, data->key, CCMP_TK_LEN);
 413
 414         if (seq) {
 415                 seq[0] = data->tx_pn[5];
 416                 seq[1] = data->tx_pn[4];
 417                 seq[2] = data->tx_pn[3];
 418                 seq[3] = data->tx_pn[2];
 419                 seq[4] = data->tx_pn[1];
 420                 seq[5] = data->tx_pn[0];
 421         }
 422
 423         return CCMP_TK_LEN;
 424 }
 425
 426
 427 static char * ieee80211_ccmp_print_stats(char *p, void *priv)
 428 {
 429         struct ieee80211_ccmp_data *ccmp = priv;
 430         p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
 431                      "tx_pn=%pm rx_pn=%pm "
 432                      "format_errors=%d replays=%d decrypt_errors=%d\n",
 433                      ccmp->key_idx, ccmp->key_set,
 434                      ccmp->tx_pn, ccmp->rx_pn,
 435                      ccmp->dot11RSNAStatsCCMPFormatErrors,
 436                      ccmp->dot11RSNAStatsCCMPReplays,
 437                      ccmp->dot11RSNAStatsCCMPDecryptErrors);
 438
 439         return p;
 440 }
 441
 442 void ieee80211_ccmp_null(void)
 443 {
 444         return;
 445 }
 446
 447 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
 448         .name                   = "CCMP",
 449         .init                   = ieee80211_ccmp_init,
 450         .deinit                 = ieee80211_ccmp_deinit,
 451         .encrypt_mpdu           = ieee80211_ccmp_encrypt,
 452         .decrypt_mpdu           = ieee80211_ccmp_decrypt,
 453         .encrypt_msdu           = NULL,
 454         .decrypt_msdu           = NULL,
 455         .set_key                = ieee80211_ccmp_set_key,
 456         .get_key                = ieee80211_ccmp_get_key,
 457         .print_stats            = ieee80211_ccmp_print_stats,
 458         .extra_prefix_len       = CCMP_HDR_LEN,
 459         .extra_postfix_len      = CCMP_MIC_LEN,
 460         .owner                  = THIS_MODULE,
 461 };
 462
 463 int __init ieee80211_crypto_ccmp_init(void)
 464 {
 465         return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
 466 }
 467
 468 void ieee80211_crypto_ccmp_exit(void)
 469 {
 470         ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
 471 }