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