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/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 static 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         // fixed by David :2006.9.6
 134         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 135                        (WLAN_FC_GET_STYPE(fc) & 0x80));
 136         aad_len = 22;
 137         if (a4_included)
 138                 aad_len += 6;
 139         if (qc_included) {
 140                 pos = (u8 *) &hdr->addr4;
 141                 if (a4_included)
 142                         pos += 6;
 143                 qc = *pos & 0x0f;
 144                 aad_len += 2;
 145         }
 146         /* CCM Initial Block:
 147          * Flag (Include authentication header, M=3 (8-octet MIC),
 148          *       L=1 (2-octet Dlen))
 149          * Nonce: 0x00 | A2 | PN
 150          * Dlen */
 151         b0[0] = 0x59;
 152         b0[1] = qc;
 153         memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
 154         memcpy(b0 + 8, pn, CCMP_PN_LEN);
 155         b0[14] = (dlen >> 8) & 0xff;
 156         b0[15] = dlen & 0xff;
 157
 158         /* AAD:
 159          * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
 160          * A1 | A2 | A3
 161          * SC with bits 4..15 (seq#) masked to zero
 162          * A4 (if present)
 163          * QC (if present)
 164          */
 165         pos = (u8 *) hdr;
 166         aad[0] = 0; /* aad_len >> 8 */
 167         aad[1] = aad_len & 0xff;
 168         aad[2] = pos[0] & 0x8f;
 169         aad[3] = pos[1] & 0xc7;
 170         memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
 171         pos = (u8 *) &hdr->seq_ctl;
 172         aad[22] = pos[0] & 0x0f;
 173         aad[23] = 0; /* all bits masked */
 174         memset(aad + 24, 0, 8);
 175         if (a4_included)
 176                 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
 177         if (qc_included) {
 178                 aad[a4_included ? 30 : 24] = qc;
 179                 /* rest of QC masked */
 180         }
 181
 182         /* Start with the first block and AAD */
 183         ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
 184         xor_block(auth, aad, AES_BLOCK_LEN);
 185         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 186         xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
 187         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 188         b0[0] &= 0x07;
 189         b0[14] = b0[15] = 0;
 190         ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
 191 }
 192
 193
 194
 195 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 196 {
 197         struct ieee80211_ccmp_data *key = priv;
 198         int data_len, i;
 199         u8 *pos;
 200         struct ieee80211_hdr_4addr *hdr;
 201         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 202
 203         if (skb_headroom(skb) < CCMP_HDR_LEN ||
 204             skb_tailroom(skb) < CCMP_MIC_LEN ||
 205             skb->len < hdr_len)
 206                 return -1;
 207
 208         data_len = skb->len - hdr_len;
 209         pos = skb_push(skb, CCMP_HDR_LEN);
 210         memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
 211         pos += hdr_len;
 212 //      mic = skb_put(skb, CCMP_MIC_LEN);
 213
 214         i = CCMP_PN_LEN - 1;
 215         while (i >= 0) {
 216                 key->tx_pn[i]++;
 217                 if (key->tx_pn[i] != 0)
 218                         break;
 219                 i--;
 220         }
 221
 222         *pos++ = key->tx_pn[5];
 223         *pos++ = key->tx_pn[4];
 224         *pos++ = 0;
 225         *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
 226         *pos++ = key->tx_pn[3];
 227         *pos++ = key->tx_pn[2];
 228         *pos++ = key->tx_pn[1];
 229         *pos++ = key->tx_pn[0];
 230
 231
 232         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 233         if (!tcb_desc->bHwSec)
 234         {
 235                 int blocks, last, len;
 236                 u8 *mic;
 237                 u8 *b0 = key->tx_b0;
 238                 u8 *b = key->tx_b;
 239                 u8 *e = key->tx_e;
 240                 u8 *s0 = key->tx_s0;
 241
 242                 //mic is moved to here by john
 243                 mic = skb_put(skb, CCMP_MIC_LEN);
 244
 245                 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
 246
 247                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 248                 last = data_len % AES_BLOCK_LEN;
 249
 250                 for (i = 1; i <= blocks; i++) {
 251                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 252                         /* Authentication */
 253                         xor_block(b, pos, len);
 254                         ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
 255                         /* Encryption, with counter */
 256                         b0[14] = (i >> 8) & 0xff;
 257                         b0[15] = i & 0xff;
 258                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
 259                         xor_block(pos, e, len);
 260                         pos += len;
 261                 }
 262
 263                 for (i = 0; i < CCMP_MIC_LEN; i++)
 264                         mic[i] = b[i] ^ s0[i];
 265         }
 266         return 0;
 267 }
 268
 269
 270 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 271 {
 272         struct ieee80211_ccmp_data *key = priv;
 273         u8 keyidx, *pos;
 274         struct ieee80211_hdr_4addr *hdr;
 275         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 276         u8 pn[6];
 277
 278         if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
 279                 key->dot11RSNAStatsCCMPFormatErrors++;
 280                 return -1;
 281         }
 282
 283         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 284         pos = skb->data + hdr_len;
 285         keyidx = pos[3];
 286         if (!(keyidx & (1 << 5))) {
 287                 if (net_ratelimit()) {
 288                         printk(KERN_DEBUG "CCMP: received packet without ExtIV"
 289                                " flag from %pM\n", hdr->addr2);
 290                 }
 291                 key->dot11RSNAStatsCCMPFormatErrors++;
 292                 return -2;
 293         }
 294         keyidx >>= 6;
 295         if (key->key_idx != keyidx) {
 296                 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
 297                        "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
 298                 return -6;
 299         }
 300         if (!key->key_set) {
 301                 if (net_ratelimit()) {
 302                         printk(KERN_DEBUG "CCMP: received packet from %pM"
 303                                " with keyid=%d that does not have a configured"
 304                                " key\n", hdr->addr2, keyidx);
 305                 }
 306                 return -3;
 307         }
 308
 309         pn[0] = pos[7];
 310         pn[1] = pos[6];
 311         pn[2] = pos[5];
 312         pn[3] = pos[4];
 313         pn[4] = pos[1];
 314         pn[5] = pos[0];
 315         pos += 8;
 316
 317         if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
 318                 if (net_ratelimit()) {
 319                         printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
 320                                " previous PN %pm received PN %pm\n",
 321                                hdr->addr2, key->rx_pn, pn);
 322                 }
 323                 key->dot11RSNAStatsCCMPReplays++;
 324                 return -4;
 325         }
 326         if (!tcb_desc->bHwSec)
 327         {
 328                 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
 329                 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
 330                 u8 *b0 = key->rx_b0;
 331                 u8 *b = key->rx_b;
 332                 u8 *a = key->rx_a;
 333                 int i, blocks, last, len;
 334
 335
 336                 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
 337                 xor_block(mic, b, CCMP_MIC_LEN);
 338
 339                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 340                 last = data_len % AES_BLOCK_LEN;
 341
 342                 for (i = 1; i <= blocks; i++) {
 343                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 344                         /* Decrypt, with counter */
 345                         b0[14] = (i >> 8) & 0xff;
 346                         b0[15] = i & 0xff;
 347                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
 348                         xor_block(pos, b, len);
 349                         /* Authentication */
 350                         xor_block(a, pos, len);
 351                         ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
 352                         pos += len;
 353                 }
 354
 355                 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
 356                         if (net_ratelimit()) {
 357                                 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
 358                                 "%pM\n", hdr->addr2);
 359                         }
 360                         key->dot11RSNAStatsCCMPDecryptErrors++;
 361                         return -5;
 362                 }
 363
 364                 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
 365         }
 366         /* Remove hdr and MIC */
 367         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
 368         skb_pull(skb, CCMP_HDR_LEN);
 369         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 370
 371         return keyidx;
 372 }
 373
 374
 375 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
 376 {
 377         struct ieee80211_ccmp_data *data = priv;
 378         int keyidx;
 379         struct crypto_tfm *tfm = data->tfm;
 380
 381         keyidx = data->key_idx;
 382         memset(data, 0, sizeof(*data));
 383         data->key_idx = keyidx;
 384         data->tfm = tfm;
 385         if (len == CCMP_TK_LEN) {
 386                 memcpy(data->key, key, CCMP_TK_LEN);
 387                 data->key_set = 1;
 388                 if (seq) {
 389                         data->rx_pn[0] = seq[5];
 390                         data->rx_pn[1] = seq[4];
 391                         data->rx_pn[2] = seq[3];
 392                         data->rx_pn[3] = seq[2];
 393                         data->rx_pn[4] = seq[1];
 394                         data->rx_pn[5] = seq[0];
 395                 }
 396                 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
 397         } else if (len == 0)
 398                 data->key_set = 0;
 399         else
 400                 return -1;
 401
 402         return 0;
 403 }
 404
 405
 406 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
 407 {
 408         struct ieee80211_ccmp_data *data = priv;
 409
 410         if (len < CCMP_TK_LEN)
 411                 return -1;
 412
 413         if (!data->key_set)
 414                 return 0;
 415         memcpy(key, data->key, CCMP_TK_LEN);
 416
 417         if (seq) {
 418                 seq[0] = data->tx_pn[5];
 419                 seq[1] = data->tx_pn[4];
 420                 seq[2] = data->tx_pn[3];
 421                 seq[3] = data->tx_pn[2];
 422                 seq[4] = data->tx_pn[1];
 423                 seq[5] = data->tx_pn[0];
 424         }
 425
 426         return CCMP_TK_LEN;
 427 }
 428
 429
 430 static char *ieee80211_ccmp_print_stats(char *p, void *priv)
 431 {
 432         struct ieee80211_ccmp_data *ccmp = priv;
 433         p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
 434                      "tx_pn=%pm rx_pn=%pm "
 435                      "format_errors=%d replays=%d decrypt_errors=%d\n",
 436                      ccmp->key_idx, ccmp->key_set,
 437                      ccmp->tx_pn, ccmp->rx_pn,
 438                      ccmp->dot11RSNAStatsCCMPFormatErrors,
 439                      ccmp->dot11RSNAStatsCCMPReplays,
 440                      ccmp->dot11RSNAStatsCCMPDecryptErrors);
 441
 442         return p;
 443 }
 444
 445 void ieee80211_ccmp_null(void)
 446 {
 447 //    printk("============>%s()\n", __func__);
 448         return;
 449 }
 450
 451 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
 452         .name                   = "CCMP",
 453         .init                   = ieee80211_ccmp_init,
 454         .deinit                 = ieee80211_ccmp_deinit,
 455         .encrypt_mpdu           = ieee80211_ccmp_encrypt,
 456         .decrypt_mpdu           = ieee80211_ccmp_decrypt,
 457         .encrypt_msdu           = NULL,
 458         .decrypt_msdu           = NULL,
 459         .set_key                = ieee80211_ccmp_set_key,
 460         .get_key                = ieee80211_ccmp_get_key,
 461         .print_stats            = ieee80211_ccmp_print_stats,
 462         .extra_prefix_len       = CCMP_HDR_LEN,
 463         .extra_postfix_len      = CCMP_MIC_LEN,
 464         .owner                  = THIS_MODULE,
 465 };
 466
 467 int __init ieee80211_crypto_ccmp_init(void)
 468 {
 469         return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
 470 }
 471
 472 void __exit ieee80211_crypto_ccmp_exit(void)
 473 {
 474         ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
 475 }