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   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 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
  28 #include "rtl_crypto.h"
  29 #else
  30 #include <linux/crypto.h>
  31 #endif
  32
  33 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
  34     #include <asm/scatterlist.h>
  35 #else
  36     #include <linux/scatterlist.h>
  37 #endif
  38 //#include <asm/scatterlist.h>
  39
  40 MODULE_AUTHOR("Jouni Malinen");
  41 MODULE_DESCRIPTION("Host AP crypt: CCMP");
  42 MODULE_LICENSE("GPL");
  43
  44 #ifndef OPENSUSE_SLED
  45 #define OPENSUSE_SLED 0
  46 #endif
  47
  48 #define AES_BLOCK_LEN 16
  49 #define CCMP_HDR_LEN 8
  50 #define CCMP_MIC_LEN 8
  51 #define CCMP_TK_LEN 16
  52 #define CCMP_PN_LEN 6
  53
  54 struct ieee80211_ccmp_data {
  55         u8 key[CCMP_TK_LEN];
  56         int key_set;
  57
  58         u8 tx_pn[CCMP_PN_LEN];
  59         u8 rx_pn[CCMP_PN_LEN];
  60
  61         u32 dot11RSNAStatsCCMPFormatErrors;
  62         u32 dot11RSNAStatsCCMPReplays;
  63         u32 dot11RSNAStatsCCMPDecryptErrors;
  64
  65         int key_idx;
  66
  67         struct crypto_tfm *tfm;
  68
  69         /* scratch buffers for virt_to_page() (crypto API) */
  70         u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
  71                 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
  72         u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
  73 };
  74
  75 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
  76                              const u8 pt[16], u8 ct[16])
  77 {
  78 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
  79         struct scatterlist src, dst;
  80
  81         src.page = virt_to_page(pt);
  82         src.offset = offset_in_page(pt);
  83         src.length = AES_BLOCK_LEN;
  84
  85         dst.page = virt_to_page(ct);
  86         dst.offset = offset_in_page(ct);
  87         dst.length = AES_BLOCK_LEN;
  88
  89         crypto_cipher_encrypt(tfm, &dst, &src, AES_BLOCK_LEN);
  90 #else
  91         crypto_cipher_encrypt_one((void*)tfm, ct, pt);
  92 #endif
  93 }
  94
  95 static void * ieee80211_ccmp_init(int key_idx)
  96 {
  97         struct ieee80211_ccmp_data *priv;
  98
  99         priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
 100         if (priv == NULL)
 101                 goto fail;
 102         memset(priv, 0, sizeof(*priv));
 103         priv->key_idx = key_idx;
 104
 105 #if((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)) && (!OPENSUSE_SLED))
 106         priv->tfm = crypto_alloc_tfm("aes", 0);
 107         if (priv->tfm == NULL) {
 108                 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
 109                        "crypto API aes\n");
 110                 goto fail;
 111         }
 112        #else
 113        priv->tfm = (void*)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
 114         if (IS_ERR(priv->tfm)) {
 115                 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
 116                        "crypto API aes\n");
 117                 priv->tfm = NULL;
 118                 goto fail;
 119         }
 120         #endif
 121         return priv;
 122
 123 fail:
 124         if (priv) {
 125                 if (priv->tfm)
 126                         #if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))
 127                         crypto_free_tfm(priv->tfm);
 128                     #else
 129                         crypto_free_cipher((void*)priv->tfm);
 130                       #endif
 131                 kfree(priv);
 132         }
 133
 134         return NULL;
 135 }
 136
 137
 138 static void ieee80211_ccmp_deinit(void *priv)
 139 {
 140         struct ieee80211_ccmp_data *_priv = priv;
 141         if (_priv && _priv->tfm)
 142 #if(LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21))
 143                 crypto_free_tfm(_priv->tfm);
 144 #else
 145                 crypto_free_cipher((void*)_priv->tfm);
 146 #endif
 147         kfree(priv);
 148 }
 149
 150
 151 static inline void xor_block(u8 *b, u8 *a, size_t len)
 152 {
 153         int i;
 154         for (i = 0; i < len; i++)
 155                 b[i] ^= a[i];
 156 }
 157
 158
 159
 160 static void ccmp_init_blocks(struct crypto_tfm *tfm,
 161                              struct ieee80211_hdr_4addr *hdr,
 162                              u8 *pn, size_t dlen, u8 *b0, u8 *auth,
 163                              u8 *s0)
 164 {
 165         u8 *pos, qc = 0;
 166         size_t aad_len;
 167         u16 fc;
 168         int a4_included, qc_included;
 169         u8 aad[2 * AES_BLOCK_LEN];
 170
 171         fc = le16_to_cpu(hdr->frame_ctl);
 172         a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 173                        (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
 174         /*
 175         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 176                        (WLAN_FC_GET_STYPE(fc) & 0x08));
 177         */
 178         // fixed by David :2006.9.6
 179         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 180                        (WLAN_FC_GET_STYPE(fc) & 0x80));
 181         aad_len = 22;
 182         if (a4_included)
 183                 aad_len += 6;
 184         if (qc_included) {
 185                 pos = (u8 *) &hdr->addr4;
 186                 if (a4_included)
 187                         pos += 6;
 188                 qc = *pos & 0x0f;
 189                 aad_len += 2;
 190         }
 191         /* CCM Initial Block:
 192          * Flag (Include authentication header, M=3 (8-octet MIC),
 193          *       L=1 (2-octet Dlen))
 194          * Nonce: 0x00 | A2 | PN
 195          * Dlen */
 196         b0[0] = 0x59;
 197         b0[1] = qc;
 198         memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
 199         memcpy(b0 + 8, pn, CCMP_PN_LEN);
 200         b0[14] = (dlen >> 8) & 0xff;
 201         b0[15] = dlen & 0xff;
 202
 203         /* AAD:
 204          * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
 205          * A1 | A2 | A3
 206          * SC with bits 4..15 (seq#) masked to zero
 207          * A4 (if present)
 208          * QC (if present)
 209          */
 210         pos = (u8 *) hdr;
 211         aad[0] = 0; /* aad_len >> 8 */
 212         aad[1] = aad_len & 0xff;
 213         aad[2] = pos[0] & 0x8f;
 214         aad[3] = pos[1] & 0xc7;
 215         memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
 216         pos = (u8 *) &hdr->seq_ctl;
 217         aad[22] = pos[0] & 0x0f;
 218         aad[23] = 0; /* all bits masked */
 219         memset(aad + 24, 0, 8);
 220         if (a4_included)
 221                 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
 222         if (qc_included) {
 223                 aad[a4_included ? 30 : 24] = qc;
 224                 /* rest of QC masked */
 225         }
 226
 227         /* Start with the first block and AAD */
 228         ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
 229         xor_block(auth, aad, AES_BLOCK_LEN);
 230         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 231         xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
 232         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 233         b0[0] &= 0x07;
 234         b0[14] = b0[15] = 0;
 235         ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
 236 }
 237
 238
 239
 240 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 241 {
 242         struct ieee80211_ccmp_data *key = priv;
 243         int data_len, i;
 244         u8 *pos;
 245         struct ieee80211_hdr_4addr *hdr;
 246         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 247
 248         if (skb_headroom(skb) < CCMP_HDR_LEN ||
 249             skb_tailroom(skb) < CCMP_MIC_LEN ||
 250             skb->len < hdr_len)
 251                 return -1;
 252
 253         data_len = skb->len - hdr_len;
 254         pos = skb_push(skb, CCMP_HDR_LEN);
 255         memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
 256         pos += hdr_len;
 257 //      mic = skb_put(skb, CCMP_MIC_LEN);
 258
 259         i = CCMP_PN_LEN - 1;
 260         while (i >= 0) {
 261                 key->tx_pn[i]++;
 262                 if (key->tx_pn[i] != 0)
 263                         break;
 264                 i--;
 265         }
 266
 267         *pos++ = key->tx_pn[5];
 268         *pos++ = key->tx_pn[4];
 269         *pos++ = 0;
 270         *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
 271         *pos++ = key->tx_pn[3];
 272         *pos++ = key->tx_pn[2];
 273         *pos++ = key->tx_pn[1];
 274         *pos++ = key->tx_pn[0];
 275
 276
 277         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 278         if (!tcb_desc->bHwSec)
 279         {
 280                 int blocks, last, len;
 281                 u8 *mic;
 282                 u8 *b0 = key->tx_b0;
 283                 u8 *b = key->tx_b;
 284                 u8 *e = key->tx_e;
 285                 u8 *s0 = key->tx_s0;
 286
 287                 //mic is moved to here by john
 288                 mic = skb_put(skb, CCMP_MIC_LEN);
 289
 290                 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
 291
 292                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 293                 last = data_len % AES_BLOCK_LEN;
 294
 295                 for (i = 1; i <= blocks; i++) {
 296                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 297                         /* Authentication */
 298                         xor_block(b, pos, len);
 299                         ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
 300                         /* Encryption, with counter */
 301                         b0[14] = (i >> 8) & 0xff;
 302                         b0[15] = i & 0xff;
 303                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
 304                         xor_block(pos, e, len);
 305                         pos += len;
 306                 }
 307
 308                 for (i = 0; i < CCMP_MIC_LEN; i++)
 309                         mic[i] = b[i] ^ s0[i];
 310         }
 311         return 0;
 312 }
 313
 314
 315 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 316 {
 317         struct ieee80211_ccmp_data *key = priv;
 318         u8 keyidx, *pos;
 319         struct ieee80211_hdr_4addr *hdr;
 320         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 321         u8 pn[6];
 322
 323         if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
 324                 key->dot11RSNAStatsCCMPFormatErrors++;
 325                 return -1;
 326         }
 327
 328         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 329         pos = skb->data + hdr_len;
 330         keyidx = pos[3];
 331         if (!(keyidx & (1 << 5))) {
 332                 if (net_ratelimit()) {
 333                         printk(KERN_DEBUG "CCMP: received packet without ExtIV"
 334                                " flag from %pM\n", hdr->addr2);
 335                 }
 336                 key->dot11RSNAStatsCCMPFormatErrors++;
 337                 return -2;
 338         }
 339         keyidx >>= 6;
 340         if (key->key_idx != keyidx) {
 341                 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
 342                        "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
 343                 return -6;
 344         }
 345         if (!key->key_set) {
 346                 if (net_ratelimit()) {
 347                         printk(KERN_DEBUG "CCMP: received packet from %pM"
 348                                " with keyid=%d that does not have a configured"
 349                                " key\n", hdr->addr2, keyidx);
 350                 }
 351                 return -3;
 352         }
 353
 354         pn[0] = pos[7];
 355         pn[1] = pos[6];
 356         pn[2] = pos[5];
 357         pn[3] = pos[4];
 358         pn[4] = pos[1];
 359         pn[5] = pos[0];
 360         pos += 8;
 361
 362         if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
 363                 if (net_ratelimit()) {
 364                         //printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
 365                         //       " previous PN %pm received PN %pm\n",
 366                         //       hdr->addr2, key->rx_pn, pn);
 367                 }
 368                 key->dot11RSNAStatsCCMPReplays++;
 369                 return -4;
 370         }
 371         if (!tcb_desc->bHwSec)
 372         {
 373                 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
 374                 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
 375                 u8 *b0 = key->rx_b0;
 376                 u8 *b = key->rx_b;
 377                 u8 *a = key->rx_a;
 378                 int i, blocks, last, len;
 379
 380
 381                 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
 382                 xor_block(mic, b, CCMP_MIC_LEN);
 383
 384                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 385                 last = data_len % AES_BLOCK_LEN;
 386
 387                 for (i = 1; i <= blocks; i++) {
 388                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 389                         /* Decrypt, with counter */
 390                         b0[14] = (i >> 8) & 0xff;
 391                         b0[15] = i & 0xff;
 392                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
 393                         xor_block(pos, b, len);
 394                         /* Authentication */
 395                         xor_block(a, pos, len);
 396                         ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
 397                         pos += len;
 398                 }
 399
 400                 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
 401                         if (net_ratelimit()) {
 402                                 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
 403                                 "%pM\n", hdr->addr2);
 404                         }
 405                         key->dot11RSNAStatsCCMPDecryptErrors++;
 406                         return -5;
 407                 }
 408
 409                 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
 410         }
 411         /* Remove hdr and MIC */
 412         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
 413         skb_pull(skb, CCMP_HDR_LEN);
 414         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 415
 416         return keyidx;
 417 }
 418
 419
 420 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
 421 {
 422         struct ieee80211_ccmp_data *data = priv;
 423         int keyidx;
 424         struct crypto_tfm *tfm = data->tfm;
 425
 426         keyidx = data->key_idx;
 427         memset(data, 0, sizeof(*data));
 428         data->key_idx = keyidx;
 429         data->tfm = tfm;
 430         if (len == CCMP_TK_LEN) {
 431                 memcpy(data->key, key, CCMP_TK_LEN);
 432                 data->key_set = 1;
 433                 if (seq) {
 434                         data->rx_pn[0] = seq[5];
 435                         data->rx_pn[1] = seq[4];
 436                         data->rx_pn[2] = seq[3];
 437                         data->rx_pn[3] = seq[2];
 438                         data->rx_pn[4] = seq[1];
 439                         data->rx_pn[5] = seq[0];
 440                 }
 441                 crypto_cipher_setkey((void*)data->tfm, data->key, CCMP_TK_LEN);
 442         } else if (len == 0)
 443                 data->key_set = 0;
 444         else
 445                 return -1;
 446
 447         return 0;
 448 }
 449
 450
 451 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
 452 {
 453         struct ieee80211_ccmp_data *data = priv;
 454
 455         if (len < CCMP_TK_LEN)
 456                 return -1;
 457
 458         if (!data->key_set)
 459                 return 0;
 460         memcpy(key, data->key, CCMP_TK_LEN);
 461
 462         if (seq) {
 463                 seq[0] = data->tx_pn[5];
 464                 seq[1] = data->tx_pn[4];
 465                 seq[2] = data->tx_pn[3];
 466                 seq[3] = data->tx_pn[2];
 467                 seq[4] = data->tx_pn[1];
 468                 seq[5] = data->tx_pn[0];
 469         }
 470
 471         return CCMP_TK_LEN;
 472 }
 473
 474
 475 static char * ieee80211_ccmp_print_stats(char *p, void *priv)
 476 {
 477         struct ieee80211_ccmp_data *ccmp = priv;
 478         int i;
 479
 480         p += sprintf(p, "key[%d] alg=CCMP key_set=%d tx_pn=",
 481                      ccmp->key_idx, ccmp->key_set);
 482
 483         for (i = 0; i < ARRAY_SIZE(ccmp->tx_pn); i++)
 484                 p += sprintf(p, "%02x", ccmp->tx_pn[i]);
 485
 486         sprintf(p, " rx_pn=");
 487         for (i = 0; i < ARRAY_SIZE(ccmp->rx_pn); i++)
 488                 p += sprintf(p, "%02x", ccmp->tx_pn[i]);
 489
 490         p += sprintf(p, " format_errors=%d replays=%d decrypt_errors=%d\n",
 491                      ccmp->dot11RSNAStatsCCMPFormatErrors,
 492                      ccmp->dot11RSNAStatsCCMPReplays,
 493                      ccmp->dot11RSNAStatsCCMPDecryptErrors);
 494
 495         return p;
 496 }
 497
 498 void ieee80211_ccmp_null(void)
 499 {
 500 //    printk("============>%s()\n", __FUNCTION__);
 501         return;
 502 }
 503
 504 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
 505         .name                   = "CCMP",
 506         .init                   = ieee80211_ccmp_init,
 507         .deinit                 = ieee80211_ccmp_deinit,
 508         .encrypt_mpdu           = ieee80211_ccmp_encrypt,
 509         .decrypt_mpdu           = ieee80211_ccmp_decrypt,
 510         .encrypt_msdu           = NULL,
 511         .decrypt_msdu           = NULL,
 512         .set_key                = ieee80211_ccmp_set_key,
 513         .get_key                = ieee80211_ccmp_get_key,
 514         .print_stats            = ieee80211_ccmp_print_stats,
 515         .extra_prefix_len       = CCMP_HDR_LEN,
 516         .extra_postfix_len      = CCMP_MIC_LEN,
 517         .owner                  = THIS_MODULE,
 518 };
 519
 520
 521 int __init ieee80211_crypto_ccmp_init(void)
 522 {
 523         return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
 524 }
 525
 526
 527 void ieee80211_crypto_ccmp_exit(void)
 528 {
 529         ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
 530 }
 531
 532 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
 533 //EXPORT_SYMBOL(ieee80211_ccmp_null);
 534 #else
 535 EXPORT_SYMBOL_NOVERS(ieee80211_ccmp_null);
 536 #endif
 537
 538 //module_init(ieee80211_crypto_ccmp_init);
 539 //module_exit(ieee80211_crypto_ccmp_exit);