drivers/staging/rtl8192e/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/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 <linux/netdevice.h>
  20 #include <linux/if_ether.h>
  21 #include <linux/if_arp.h>
  22 #include <asm/string.h>
  23 #include <linux/wireless.h>
  24
  25 #include "ieee80211.h"
  26
  27 #include <linux/crypto.h>
  28
  29     #include <linux/scatterlist.h>
  30
  31 MODULE_AUTHOR("Jouni Malinen");
  32 MODULE_DESCRIPTION("Host AP crypt: CCMP");
  33 MODULE_LICENSE("GPL");
  34
  35 #ifndef OPENSUSE_SLED
  36 #define OPENSUSE_SLED 0
  37 #endif
  38
  39 #define AES_BLOCK_LEN 16
  40 #define CCMP_HDR_LEN 8
  41 #define CCMP_MIC_LEN 8
  42 #define CCMP_TK_LEN 16
  43 #define CCMP_PN_LEN 6
  44
  45 struct ieee80211_ccmp_data {
  46         u8 key[CCMP_TK_LEN];
  47         int key_set;
  48
  49         u8 tx_pn[CCMP_PN_LEN];
  50         u8 rx_pn[CCMP_PN_LEN];
  51
  52         u32 dot11RSNAStatsCCMPFormatErrors;
  53         u32 dot11RSNAStatsCCMPReplays;
  54         u32 dot11RSNAStatsCCMPDecryptErrors;
  55
  56         int key_idx;
  57
  58         struct crypto_tfm *tfm;
  59
  60         /* scratch buffers for virt_to_page() (crypto API) */
  61         u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
  62                 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
  63         u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
  64 };
  65
  66 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
  67                              const u8 pt[16], u8 ct[16])
  68 {
  69         crypto_cipher_encrypt_one((void*)tfm, ct, pt);
  70 }
  71
  72 static void * ieee80211_ccmp_init(int key_idx)
  73 {
  74         struct ieee80211_ccmp_data *priv;
  75
  76         priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
  77         if (priv == NULL)
  78                 goto fail;
  79         priv->key_idx = key_idx;
  80
  81        priv->tfm = (void*)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
  82         if (IS_ERR(priv->tfm)) {
  83                 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
  84                        "crypto API aes\n");
  85                 priv->tfm = NULL;
  86                 goto fail;
  87         }
  88         return priv;
  89
  90 fail:
  91         if (priv) {
  92                 if (priv->tfm)
  93                         crypto_free_cipher((void*)priv->tfm);
  94                 kfree(priv);
  95         }
  96
  97         return NULL;
  98 }
  99
 100
 101 static void ieee80211_ccmp_deinit(void *priv)
 102 {
 103         struct ieee80211_ccmp_data *_priv = priv;
 104         if (_priv && _priv->tfm)
 105                 crypto_free_cipher((void*)_priv->tfm);
 106         kfree(priv);
 107 }
 108
 109
 110 static inline void xor_block(u8 *b, u8 *a, size_t len)
 111 {
 112         int i;
 113         for (i = 0; i < len; i++)
 114                 b[i] ^= a[i];
 115 }
 116
 117
 118
 119 static void ccmp_init_blocks(struct crypto_tfm *tfm,
 120                              struct ieee80211_hdr_4addr *hdr,
 121                              u8 *pn, size_t dlen, u8 *b0, u8 *auth,
 122                              u8 *s0)
 123 {
 124         u8 *pos, qc = 0;
 125         size_t aad_len;
 126         u16 fc;
 127         int a4_included, qc_included;
 128         u8 aad[2 * AES_BLOCK_LEN];
 129
 130         fc = le16_to_cpu(hdr->frame_ctl);
 131         a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 132                        (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
 133         /*
 134         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 135                        (WLAN_FC_GET_STYPE(fc) & 0x08));
 136         */
 137         // fixed by David :2006.9.6
 138         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 139                        (WLAN_FC_GET_STYPE(fc) & 0x80));
 140         aad_len = 22;
 141         if (a4_included)
 142                 aad_len += 6;
 143         if (qc_included) {
 144                 pos = (u8 *) &hdr->addr4;
 145                 if (a4_included)
 146                         pos += 6;
 147                 qc = *pos & 0x0f;
 148                 aad_len += 2;
 149         }
 150         /* CCM Initial Block:
 151          * Flag (Include authentication header, M=3 (8-octet MIC),
 152          *       L=1 (2-octet Dlen))
 153          * Nonce: 0x00 | A2 | PN
 154          * Dlen */
 155         b0[0] = 0x59;
 156         b0[1] = qc;
 157         memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
 158         memcpy(b0 + 8, pn, CCMP_PN_LEN);
 159         b0[14] = (dlen >> 8) & 0xff;
 160         b0[15] = dlen & 0xff;
 161
 162         /* AAD:
 163          * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
 164          * A1 | A2 | A3
 165          * SC with bits 4..15 (seq#) masked to zero
 166          * A4 (if present)
 167          * QC (if present)
 168          */
 169         pos = (u8 *) hdr;
 170         aad[0] = 0; /* aad_len >> 8 */
 171         aad[1] = aad_len & 0xff;
 172         aad[2] = pos[0] & 0x8f;
 173         aad[3] = pos[1] & 0xc7;
 174         memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
 175         pos = (u8 *) &hdr->seq_ctl;
 176         aad[22] = pos[0] & 0x0f;
 177         aad[23] = 0; /* all bits masked */
 178         memset(aad + 24, 0, 8);
 179         if (a4_included)
 180                 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
 181         if (qc_included) {
 182                 aad[a4_included ? 30 : 24] = qc;
 183                 /* rest of QC masked */
 184         }
 185
 186         /* Start with the first block and AAD */
 187         ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
 188         xor_block(auth, aad, AES_BLOCK_LEN);
 189         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 190         xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
 191         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 192         b0[0] &= 0x07;
 193         b0[14] = b0[15] = 0;
 194         ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
 195 }
 196
 197
 198
 199 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 200 {
 201         struct ieee80211_ccmp_data *key = priv;
 202         int data_len, i;
 203         u8 *pos;
 204         struct ieee80211_hdr_4addr *hdr;
 205         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 206
 207         if (skb_headroom(skb) < CCMP_HDR_LEN ||
 208             skb_tailroom(skb) < CCMP_MIC_LEN ||
 209             skb->len < hdr_len)
 210                 return -1;
 211
 212         data_len = skb->len - hdr_len;
 213         pos = skb_push(skb, CCMP_HDR_LEN);
 214         memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
 215         pos += hdr_len;
 216 //      mic = skb_put(skb, CCMP_MIC_LEN);
 217
 218         i = CCMP_PN_LEN - 1;
 219         while (i >= 0) {
 220                 key->tx_pn[i]++;
 221                 if (key->tx_pn[i] != 0)
 222                         break;
 223                 i--;
 224         }
 225
 226         *pos++ = key->tx_pn[5];
 227         *pos++ = key->tx_pn[4];
 228         *pos++ = 0;
 229         *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
 230         *pos++ = key->tx_pn[3];
 231         *pos++ = key->tx_pn[2];
 232         *pos++ = key->tx_pn[1];
 233         *pos++ = key->tx_pn[0];
 234
 235
 236         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 237         if (!tcb_desc->bHwSec)
 238         {
 239                 int blocks, last, len;
 240                 u8 *mic;
 241                 u8 *b0 = key->tx_b0;
 242                 u8 *b = key->tx_b;
 243                 u8 *e = key->tx_e;
 244                 u8 *s0 = key->tx_s0;
 245
 246                 //mic is moved to here by john
 247                 mic = skb_put(skb, CCMP_MIC_LEN);
 248
 249                 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
 250
 251                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 252                 last = data_len % AES_BLOCK_LEN;
 253
 254                 for (i = 1; i <= blocks; i++) {
 255                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 256                         /* Authentication */
 257                         xor_block(b, pos, len);
 258                         ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
 259                         /* Encryption, with counter */
 260                         b0[14] = (i >> 8) & 0xff;
 261                         b0[15] = i & 0xff;
 262                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
 263                         xor_block(pos, e, len);
 264                         pos += len;
 265                 }
 266
 267                 for (i = 0; i < CCMP_MIC_LEN; i++)
 268                         mic[i] = b[i] ^ s0[i];
 269         }
 270         return 0;
 271 }
 272
 273
 274 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 275 {
 276         struct ieee80211_ccmp_data *key = priv;
 277         u8 keyidx, *pos;
 278         struct ieee80211_hdr_4addr *hdr;
 279         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 280         u8 pn[6];
 281
 282         if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
 283                 key->dot11RSNAStatsCCMPFormatErrors++;
 284                 return -1;
 285         }
 286
 287         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 288         pos = skb->data + hdr_len;
 289         keyidx = pos[3];
 290         if (!(keyidx & (1 << 5))) {
 291                 if (net_ratelimit()) {
 292                         printk(KERN_DEBUG "CCMP: received packet without ExtIV"
 293                                " flag from %pM\n", hdr->addr2);
 294                 }
 295                 key->dot11RSNAStatsCCMPFormatErrors++;
 296                 return -2;
 297         }
 298         keyidx >>= 6;
 299         if (key->key_idx != keyidx) {
 300                 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
 301                        "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
 302                 return -6;
 303         }
 304         if (!key->key_set) {
 305                 if (net_ratelimit()) {
 306                         printk(KERN_DEBUG "CCMP: received packet from %pM"
 307                                " with keyid=%d that does not have a configured"
 308                                " key\n", hdr->addr2, keyidx);
 309                 }
 310                 return -3;
 311         }
 312
 313         pn[0] = pos[7];
 314         pn[1] = pos[6];
 315         pn[2] = pos[5];
 316         pn[3] = pos[4];
 317         pn[4] = pos[1];
 318         pn[5] = pos[0];
 319         pos += 8;
 320
 321         if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
 322                 if (net_ratelimit()) {
 323                         //printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
 324                         //       " previous PN %pm received PN %pm\n",
 325                         //       hdr->addr2, key->rx_pn, pn);
 326                 }
 327                 key->dot11RSNAStatsCCMPReplays++;
 328                 return -4;
 329         }
 330         if (!tcb_desc->bHwSec)
 331         {
 332                 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
 333                 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
 334                 u8 *b0 = key->rx_b0;
 335                 u8 *b = key->rx_b;
 336                 u8 *a = key->rx_a;
 337                 int i, blocks, last, len;
 338
 339
 340                 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
 341                 xor_block(mic, b, CCMP_MIC_LEN);
 342
 343                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 344                 last = data_len % AES_BLOCK_LEN;
 345
 346                 for (i = 1; i <= blocks; i++) {
 347                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 348                         /* Decrypt, with counter */
 349                         b0[14] = (i >> 8) & 0xff;
 350                         b0[15] = i & 0xff;
 351                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
 352                         xor_block(pos, b, len);
 353                         /* Authentication */
 354                         xor_block(a, pos, len);
 355                         ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
 356                         pos += len;
 357                 }
 358
 359                 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
 360                         if (net_ratelimit()) {
 361                                 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
 362                                 "%pM\n", hdr->addr2);
 363                         }
 364                         key->dot11RSNAStatsCCMPDecryptErrors++;
 365                         return -5;
 366                 }
 367
 368                 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
 369         }
 370         /* Remove hdr and MIC */
 371         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
 372         skb_pull(skb, CCMP_HDR_LEN);
 373         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 374
 375         return keyidx;
 376 }
 377
 378
 379 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
 380 {
 381         struct ieee80211_ccmp_data *data = priv;
 382         int keyidx;
 383         struct crypto_tfm *tfm = data->tfm;
 384
 385         keyidx = data->key_idx;
 386         memset(data, 0, sizeof(*data));
 387         data->key_idx = keyidx;
 388         data->tfm = tfm;
 389         if (len == CCMP_TK_LEN) {
 390                 memcpy(data->key, key, CCMP_TK_LEN);
 391                 data->key_set = 1;
 392                 if (seq) {
 393                         data->rx_pn[0] = seq[5];
 394                         data->rx_pn[1] = seq[4];
 395                         data->rx_pn[2] = seq[3];
 396                         data->rx_pn[3] = seq[2];
 397                         data->rx_pn[4] = seq[1];
 398                         data->rx_pn[5] = seq[0];
 399                 }
 400                 crypto_cipher_setkey((void*)data->tfm, data->key, CCMP_TK_LEN);
 401         } else if (len == 0)
 402                 data->key_set = 0;
 403         else
 404                 return -1;
 405
 406         return 0;
 407 }
 408
 409
 410 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
 411 {
 412         struct ieee80211_ccmp_data *data = priv;
 413
 414         if (len < CCMP_TK_LEN)
 415                 return -1;
 416
 417         if (!data->key_set)
 418                 return 0;
 419         memcpy(key, data->key, CCMP_TK_LEN);
 420
 421         if (seq) {
 422                 seq[0] = data->tx_pn[5];
 423                 seq[1] = data->tx_pn[4];
 424                 seq[2] = data->tx_pn[3];
 425                 seq[3] = data->tx_pn[2];
 426                 seq[4] = data->tx_pn[1];
 427                 seq[5] = data->tx_pn[0];
 428         }
 429
 430         return CCMP_TK_LEN;
 431 }
 432
 433
 434 static char * ieee80211_ccmp_print_stats(char *p, void *priv)
 435 {
 436         struct ieee80211_ccmp_data *ccmp = priv;
 437         int i;
 438
 439         p += sprintf(p, "key[%d] alg=CCMP key_set=%d tx_pn=",
 440                      ccmp->key_idx, ccmp->key_set);
 441
 442         for (i = 0; i < ARRAY_SIZE(ccmp->tx_pn); i++)
 443                 p += sprintf(p, "%02x", ccmp->tx_pn[i]);
 444
 445         sprintf(p, " rx_pn=");
 446         for (i = 0; i < ARRAY_SIZE(ccmp->rx_pn); i++)
 447                 p += sprintf(p, "%02x", ccmp->tx_pn[i]);
 448
 449         p += sprintf(p, " format_errors=%d replays=%d decrypt_errors=%d\n",
 450                      ccmp->dot11RSNAStatsCCMPFormatErrors,
 451                      ccmp->dot11RSNAStatsCCMPReplays,
 452                      ccmp->dot11RSNAStatsCCMPDecryptErrors);
 453
 454         return p;
 455 }
 456
 457 void ieee80211_ccmp_null(void)
 458 {
 459 //    printk("============>%s()\n", __FUNCTION__);
 460         return;
 461 }
 462
 463 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
 464         .name                   = "CCMP",
 465         .init                   = ieee80211_ccmp_init,
 466         .deinit                 = ieee80211_ccmp_deinit,
 467         .encrypt_mpdu           = ieee80211_ccmp_encrypt,
 468         .decrypt_mpdu           = ieee80211_ccmp_decrypt,
 469         .encrypt_msdu           = NULL,
 470         .decrypt_msdu           = NULL,
 471         .set_key                = ieee80211_ccmp_set_key,
 472         .get_key                = ieee80211_ccmp_get_key,
 473         .print_stats            = ieee80211_ccmp_print_stats,
 474         .extra_prefix_len       = CCMP_HDR_LEN,
 475         .extra_postfix_len      = CCMP_MIC_LEN,
 476         .owner                  = THIS_MODULE,
 477 };
 478
 479
 480 int __init ieee80211_crypto_ccmp_init(void)
 481 {
 482         return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
 483 }
 484
 485
 486 void ieee80211_crypto_ccmp_exit(void)
 487 {
 488         ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
 489 }
 490