drivers/staging/rtl8192u/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     #include <linux/scatterlist.h>
  29
  30 MODULE_AUTHOR("Jouni Malinen");
  31 MODULE_DESCRIPTION("Host AP crypt: CCMP");
  32 MODULE_LICENSE("GPL");
  33
  34 #define AES_BLOCK_LEN 16
  35 #define CCMP_HDR_LEN 8
  36 #define CCMP_MIC_LEN 8
  37 #define CCMP_TK_LEN 16
  38 #define CCMP_PN_LEN 6
  39
  40 struct ieee80211_ccmp_data {
  41         u8 key[CCMP_TK_LEN];
  42         int key_set;
  43
  44         u8 tx_pn[CCMP_PN_LEN];
  45         u8 rx_pn[CCMP_PN_LEN];
  46
  47         u32 dot11RSNAStatsCCMPFormatErrors;
  48         u32 dot11RSNAStatsCCMPReplays;
  49         u32 dot11RSNAStatsCCMPDecryptErrors;
  50
  51         int key_idx;
  52
  53         struct crypto_tfm *tfm;
  54
  55         /* scratch buffers for virt_to_page() (crypto API) */
  56         u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
  57                 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
  58         u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
  59 };
  60
  61 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
  62                              const u8 pt[16], u8 ct[16])
  63 {
  64         crypto_cipher_encrypt_one((void*)tfm, ct, pt);
  65 }
  66
  67 static void * ieee80211_ccmp_init(int key_idx)
  68 {
  69         struct ieee80211_ccmp_data *priv;
  70
  71         priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
  72         if (priv == NULL)
  73                 goto fail;
  74         memset(priv, 0, sizeof(*priv));
  75         priv->key_idx = key_idx;
  76
  77        priv->tfm = (void*)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
  78         if (IS_ERR(priv->tfm)) {
  79                 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
  80                        "crypto API aes\n");
  81                 priv->tfm = NULL;
  82                 goto fail;
  83         }
  84
  85         return priv;
  86
  87 fail:
  88         if (priv) {
  89                 if (priv->tfm)
  90                         crypto_free_cipher((void*)priv->tfm);
  91                 kfree(priv);
  92         }
  93
  94         return NULL;
  95 }
  96
  97
  98 static void ieee80211_ccmp_deinit(void *priv)
  99 {
 100         struct ieee80211_ccmp_data *_priv = priv;
 101
 102         if (_priv && _priv->tfm)
 103                 crypto_free_cipher((void*)_priv->tfm);
 104         kfree(priv);
 105 }
 106
 107
 108 static inline void xor_block(u8 *b, u8 *a, size_t len)
 109 {
 110         int i;
 111         for (i = 0; i < len; i++)
 112                 b[i] ^= a[i];
 113 }
 114
 115
 116
 117 static void ccmp_init_blocks(struct crypto_tfm *tfm,
 118                              struct ieee80211_hdr_4addr *hdr,
 119                              u8 *pn, size_t dlen, u8 *b0, u8 *auth,
 120                              u8 *s0)
 121 {
 122         u8 *pos, qc = 0;
 123         size_t aad_len;
 124         u16 fc;
 125         int a4_included, qc_included;
 126         u8 aad[2 * AES_BLOCK_LEN];
 127
 128         fc = le16_to_cpu(hdr->frame_ctl);
 129         a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 130                        (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
 131         /*
 132         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 133                        (WLAN_FC_GET_STYPE(fc) & 0x08));
 134         */
 135         // fixed by David :2006.9.6
 136         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 137                        (WLAN_FC_GET_STYPE(fc) & 0x80));
 138         aad_len = 22;
 139         if (a4_included)
 140                 aad_len += 6;
 141         if (qc_included) {
 142                 pos = (u8 *) &hdr->addr4;
 143                 if (a4_included)
 144                         pos += 6;
 145                 qc = *pos & 0x0f;
 146                 aad_len += 2;
 147         }
 148         /* CCM Initial Block:
 149          * Flag (Include authentication header, M=3 (8-octet MIC),
 150          *       L=1 (2-octet Dlen))
 151          * Nonce: 0x00 | A2 | PN
 152          * Dlen */
 153         b0[0] = 0x59;
 154         b0[1] = qc;
 155         memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
 156         memcpy(b0 + 8, pn, CCMP_PN_LEN);
 157         b0[14] = (dlen >> 8) & 0xff;
 158         b0[15] = dlen & 0xff;
 159
 160         /* AAD:
 161          * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
 162          * A1 | A2 | A3
 163          * SC with bits 4..15 (seq#) masked to zero
 164          * A4 (if present)
 165          * QC (if present)
 166          */
 167         pos = (u8 *) hdr;
 168         aad[0] = 0; /* aad_len >> 8 */
 169         aad[1] = aad_len & 0xff;
 170         aad[2] = pos[0] & 0x8f;
 171         aad[3] = pos[1] & 0xc7;
 172         memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
 173         pos = (u8 *) &hdr->seq_ctl;
 174         aad[22] = pos[0] & 0x0f;
 175         aad[23] = 0; /* all bits masked */
 176         memset(aad + 24, 0, 8);
 177         if (a4_included)
 178                 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
 179         if (qc_included) {
 180                 aad[a4_included ? 30 : 24] = qc;
 181                 /* rest of QC masked */
 182         }
 183
 184         /* Start with the first block and AAD */
 185         ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
 186         xor_block(auth, aad, AES_BLOCK_LEN);
 187         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 188         xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
 189         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 190         b0[0] &= 0x07;
 191         b0[14] = b0[15] = 0;
 192         ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
 193 }
 194
 195
 196
 197 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 198 {
 199         struct ieee80211_ccmp_data *key = priv;
 200         int data_len, i;
 201         u8 *pos;
 202         struct ieee80211_hdr_4addr *hdr;
 203         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 204
 205         if (skb_headroom(skb) < CCMP_HDR_LEN ||
 206             skb_tailroom(skb) < CCMP_MIC_LEN ||
 207             skb->len < hdr_len)
 208                 return -1;
 209
 210         data_len = skb->len - hdr_len;
 211         pos = skb_push(skb, CCMP_HDR_LEN);
 212         memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
 213         pos += hdr_len;
 214 //      mic = skb_put(skb, CCMP_MIC_LEN);
 215
 216         i = CCMP_PN_LEN - 1;
 217         while (i >= 0) {
 218                 key->tx_pn[i]++;
 219                 if (key->tx_pn[i] != 0)
 220                         break;
 221                 i--;
 222         }
 223
 224         *pos++ = key->tx_pn[5];
 225         *pos++ = key->tx_pn[4];
 226         *pos++ = 0;
 227         *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
 228         *pos++ = key->tx_pn[3];
 229         *pos++ = key->tx_pn[2];
 230         *pos++ = key->tx_pn[1];
 231         *pos++ = key->tx_pn[0];
 232
 233
 234         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 235         if (!tcb_desc->bHwSec)
 236         {
 237                 int blocks, last, len;
 238                 u8 *mic;
 239                 u8 *b0 = key->tx_b0;
 240                 u8 *b = key->tx_b;
 241                 u8 *e = key->tx_e;
 242                 u8 *s0 = key->tx_s0;
 243
 244                 //mic is moved to here by john
 245                 mic = skb_put(skb, CCMP_MIC_LEN);
 246
 247                 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
 248
 249                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 250                 last = data_len % AES_BLOCK_LEN;
 251
 252                 for (i = 1; i <= blocks; i++) {
 253                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 254                         /* Authentication */
 255                         xor_block(b, pos, len);
 256                         ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
 257                         /* Encryption, with counter */
 258                         b0[14] = (i >> 8) & 0xff;
 259                         b0[15] = i & 0xff;
 260                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
 261                         xor_block(pos, e, len);
 262                         pos += len;
 263                 }
 264
 265                 for (i = 0; i < CCMP_MIC_LEN; i++)
 266                         mic[i] = b[i] ^ s0[i];
 267         }
 268         return 0;
 269 }
 270
 271
 272 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 273 {
 274         struct ieee80211_ccmp_data *key = priv;
 275         u8 keyidx, *pos;
 276         struct ieee80211_hdr_4addr *hdr;
 277         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 278         u8 pn[6];
 279
 280         if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
 281                 key->dot11RSNAStatsCCMPFormatErrors++;
 282                 return -1;
 283         }
 284
 285         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 286         pos = skb->data + hdr_len;
 287         keyidx = pos[3];
 288         if (!(keyidx & (1 << 5))) {
 289                 if (net_ratelimit()) {
 290                         printk(KERN_DEBUG "CCMP: received packet without ExtIV"
 291                                " flag from %pM\n", hdr->addr2);
 292                 }
 293                 key->dot11RSNAStatsCCMPFormatErrors++;
 294                 return -2;
 295         }
 296         keyidx >>= 6;
 297         if (key->key_idx != keyidx) {
 298                 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
 299                        "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
 300                 return -6;
 301         }
 302         if (!key->key_set) {
 303                 if (net_ratelimit()) {
 304                         printk(KERN_DEBUG "CCMP: received packet from %pM"
 305                                " with keyid=%d that does not have a configured"
 306                                " key\n", hdr->addr2, keyidx);
 307                 }
 308                 return -3;
 309         }
 310
 311         pn[0] = pos[7];
 312         pn[1] = pos[6];
 313         pn[2] = pos[5];
 314         pn[3] = pos[4];
 315         pn[4] = pos[1];
 316         pn[5] = pos[0];
 317         pos += 8;
 318
 319         if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
 320                 if (net_ratelimit()) {
 321                         printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
 322                                " previous PN %pm received PN %pm\n",
 323                                hdr->addr2, key->rx_pn, pn);
 324                 }
 325                 key->dot11RSNAStatsCCMPReplays++;
 326                 return -4;
 327         }
 328         if (!tcb_desc->bHwSec)
 329         {
 330                 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
 331                 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
 332                 u8 *b0 = key->rx_b0;
 333                 u8 *b = key->rx_b;
 334                 u8 *a = key->rx_a;
 335                 int i, blocks, last, len;
 336
 337
 338                 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
 339                 xor_block(mic, b, CCMP_MIC_LEN);
 340
 341                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 342                 last = data_len % AES_BLOCK_LEN;
 343
 344                 for (i = 1; i <= blocks; i++) {
 345                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 346                         /* Decrypt, with counter */
 347                         b0[14] = (i >> 8) & 0xff;
 348                         b0[15] = i & 0xff;
 349                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
 350                         xor_block(pos, b, len);
 351                         /* Authentication */
 352                         xor_block(a, pos, len);
 353                         ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
 354                         pos += len;
 355                 }
 356
 357                 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
 358                         if (net_ratelimit()) {
 359                                 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
 360                                 "%pM\n", hdr->addr2);
 361                         }
 362                         key->dot11RSNAStatsCCMPDecryptErrors++;
 363                         return -5;
 364                 }
 365
 366                 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
 367         }
 368         /* Remove hdr and MIC */
 369         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
 370         skb_pull(skb, CCMP_HDR_LEN);
 371         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 372
 373         return keyidx;
 374 }
 375
 376
 377 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
 378 {
 379         struct ieee80211_ccmp_data *data = priv;
 380         int keyidx;
 381         struct crypto_tfm *tfm = data->tfm;
 382
 383         keyidx = data->key_idx;
 384         memset(data, 0, sizeof(*data));
 385         data->key_idx = keyidx;
 386         data->tfm = tfm;
 387         if (len == CCMP_TK_LEN) {
 388                 memcpy(data->key, key, CCMP_TK_LEN);
 389                 data->key_set = 1;
 390                 if (seq) {
 391                         data->rx_pn[0] = seq[5];
 392                         data->rx_pn[1] = seq[4];
 393                         data->rx_pn[2] = seq[3];
 394                         data->rx_pn[3] = seq[2];
 395                         data->rx_pn[4] = seq[1];
 396                         data->rx_pn[5] = seq[0];
 397                 }
 398                 crypto_cipher_setkey((void*)data->tfm, data->key, CCMP_TK_LEN);
 399         } else if (len == 0)
 400                 data->key_set = 0;
 401         else
 402                 return -1;
 403
 404         return 0;
 405 }
 406
 407
 408 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
 409 {
 410         struct ieee80211_ccmp_data *data = priv;
 411
 412         if (len < CCMP_TK_LEN)
 413                 return -1;
 414
 415         if (!data->key_set)
 416                 return 0;
 417         memcpy(key, data->key, CCMP_TK_LEN);
 418
 419         if (seq) {
 420                 seq[0] = data->tx_pn[5];
 421                 seq[1] = data->tx_pn[4];
 422                 seq[2] = data->tx_pn[3];
 423                 seq[3] = data->tx_pn[2];
 424                 seq[4] = data->tx_pn[1];
 425                 seq[5] = data->tx_pn[0];
 426         }
 427
 428         return CCMP_TK_LEN;
 429 }
 430
 431
 432 static char * ieee80211_ccmp_print_stats(char *p, void *priv)
 433 {
 434         struct ieee80211_ccmp_data *ccmp = priv;
 435         p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
 436                      "tx_pn=%pm rx_pn=%pm "
 437                      "format_errors=%d replays=%d decrypt_errors=%d\n",
 438                      ccmp->key_idx, ccmp->key_set,
 439                      ccmp->tx_pn, ccmp->rx_pn,
 440                      ccmp->dot11RSNAStatsCCMPFormatErrors,
 441                      ccmp->dot11RSNAStatsCCMPReplays,
 442                      ccmp->dot11RSNAStatsCCMPDecryptErrors);
 443
 444         return p;
 445 }
 446
 447 void ieee80211_ccmp_null(void)
 448 {
 449 //    printk("============>%s()\n", __FUNCTION__);
 450         return;
 451 }
 452
 453 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
 454         .name                   = "CCMP",
 455         .init                   = ieee80211_ccmp_init,
 456         .deinit                 = ieee80211_ccmp_deinit,
 457         .encrypt_mpdu           = ieee80211_ccmp_encrypt,
 458         .decrypt_mpdu           = ieee80211_ccmp_decrypt,
 459         .encrypt_msdu           = NULL,
 460         .decrypt_msdu           = NULL,
 461         .set_key                = ieee80211_ccmp_set_key,
 462         .get_key                = ieee80211_ccmp_get_key,
 463         .print_stats            = ieee80211_ccmp_print_stats,
 464         .extra_prefix_len       = CCMP_HDR_LEN,
 465         .extra_postfix_len      = CCMP_MIC_LEN,
 466         .owner                  = THIS_MODULE,
 467 };
 468
 469 int __init ieee80211_crypto_ccmp_init(void)
 470 {
 471         return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
 472 }
 473
 474 void __exit ieee80211_crypto_ccmp_exit(void)
 475 {
 476         ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
 477 }