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