kernel/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/module.h>
  13 #include <linux/init.h>
  14 #include <linux/slab.h>
  15 #include <linux/random.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/netdevice.h>
  18 #include <linux/if_ether.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/string.h>
  21 #include <linux/wireless.h>
  22
  23 #include "ieee80211.h"
  24
  25 #include <linux/crypto.h>
  26     #include <linux/scatterlist.h>
  27
  28 MODULE_AUTHOR("Jouni Malinen");
  29 MODULE_DESCRIPTION("Host AP crypt: CCMP");
  30 MODULE_LICENSE("GPL");
  31
  32 #define AES_BLOCK_LEN 16
  33 #define CCMP_HDR_LEN 8
  34 #define CCMP_MIC_LEN 8
  35 #define CCMP_TK_LEN 16
  36 #define CCMP_PN_LEN 6
  37
  38 struct ieee80211_ccmp_data {
  39         u8 key[CCMP_TK_LEN];
  40         int key_set;
  41
  42         u8 tx_pn[CCMP_PN_LEN];
  43         u8 rx_pn[CCMP_PN_LEN];
  44
  45         u32 dot11RSNAStatsCCMPFormatErrors;
  46         u32 dot11RSNAStatsCCMPReplays;
  47         u32 dot11RSNAStatsCCMPDecryptErrors;
  48
  49         int key_idx;
  50
  51         struct crypto_tfm *tfm;
  52
  53         /* scratch buffers for virt_to_page() (crypto API) */
  54         u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
  55                 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
  56         u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
  57 };
  58
  59 static void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
  60                              const u8 pt[16], u8 ct[16])
  61 {
  62         crypto_cipher_encrypt_one((void *)tfm, ct, pt);
  63 }
  64
  65 static void *ieee80211_ccmp_init(int key_idx)
  66 {
  67         struct ieee80211_ccmp_data *priv;
  68
  69         priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
  70         if (priv == NULL)
  71                 goto fail;
  72         priv->key_idx = key_idx;
  73
  74        priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
  75         if (IS_ERR(priv->tfm)) {
  76                 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
  77                        "crypto API aes\n");
  78                 priv->tfm = NULL;
  79                 goto fail;
  80         }
  81
  82         return priv;
  83
  84 fail:
  85         if (priv) {
  86                 if (priv->tfm)
  87                         crypto_free_cipher((void *)priv->tfm);
  88                 kfree(priv);
  89         }
  90
  91         return NULL;
  92 }
  93
  94
  95 static void ieee80211_ccmp_deinit(void *priv)
  96 {
  97         struct ieee80211_ccmp_data *_priv = priv;
  98
  99         if (_priv && _priv->tfm)
 100                 crypto_free_cipher((void *)_priv->tfm);
 101         kfree(priv);
 102 }
 103
 104
 105 static inline void xor_block(u8 *b, u8 *a, size_t len)
 106 {
 107         int i;
 108         for (i = 0; i < len; i++)
 109                 b[i] ^= a[i];
 110 }
 111
 112
 113
 114 static void ccmp_init_blocks(struct crypto_tfm *tfm,
 115                              struct ieee80211_hdr_4addr *hdr,
 116                              u8 *pn, size_t dlen, u8 *b0, u8 *auth,
 117                              u8 *s0)
 118 {
 119         u8 *pos, qc = 0;
 120         size_t aad_len;
 121         u16 fc;
 122         int a4_included, qc_included;
 123         u8 aad[2 * AES_BLOCK_LEN];
 124
 125         fc = le16_to_cpu(hdr->frame_ctl);
 126         a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 127                        (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
 128         /*
 129         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 130                        (WLAN_FC_GET_STYPE(fc) & 0x08));
 131         */
 132         /* fixed by David :2006.9.6 */
 133         qc_included = (WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 134                        (WLAN_FC_GET_STYPE(fc) & 0x80);
 135         aad_len = 22;
 136         if (a4_included)
 137                 aad_len += 6;
 138         if (qc_included) {
 139                 pos = (u8 *) &hdr->addr4;
 140                 if (a4_included)
 141                         pos += 6;
 142                 qc = *pos & 0x0f;
 143                 aad_len += 2;
 144         }
 145         /* CCM Initial Block:
 146          * Flag (Include authentication header, M=3 (8-octet MIC),
 147          *       L=1 (2-octet Dlen))
 148          * Nonce: 0x00 | A2 | PN
 149          * Dlen */
 150         b0[0] = 0x59;
 151         b0[1] = qc;
 152         memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
 153         memcpy(b0 + 8, pn, CCMP_PN_LEN);
 154         b0[14] = (dlen >> 8) & 0xff;
 155         b0[15] = dlen & 0xff;
 156
 157         /* AAD:
 158          * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
 159          * A1 | A2 | A3
 160          * SC with bits 4..15 (seq#) masked to zero
 161          * A4 (if present)
 162          * QC (if present)
 163          */
 164         pos = (u8 *) hdr;
 165         aad[0] = 0; /* aad_len >> 8 */
 166         aad[1] = aad_len & 0xff;
 167         aad[2] = pos[0] & 0x8f;
 168         aad[3] = pos[1] & 0xc7;
 169         memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
 170         pos = (u8 *) &hdr->seq_ctl;
 171         aad[22] = pos[0] & 0x0f;
 172         aad[23] = 0; /* all bits masked */
 173         memset(aad + 24, 0, 8);
 174         if (a4_included)
 175                 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
 176         if (qc_included) {
 177                 aad[a4_included ? 30 : 24] = qc;
 178                 /* rest of QC masked */
 179         }
 180
 181         /* Start with the first block and AAD */
 182         ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
 183         xor_block(auth, aad, AES_BLOCK_LEN);
 184         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 185         xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
 186         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 187         b0[0] &= 0x07;
 188         b0[14] = b0[15] = 0;
 189         ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
 190 }
 191
 192
 193
 194 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 195 {
 196         struct ieee80211_ccmp_data *key = priv;
 197         int data_len, i;
 198         u8 *pos;
 199         struct ieee80211_hdr_4addr *hdr;
 200         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 201
 202         if (skb_headroom(skb) < CCMP_HDR_LEN ||
 203             skb_tailroom(skb) < CCMP_MIC_LEN ||
 204             skb->len < hdr_len)
 205                 return -1;
 206
 207         data_len = skb->len - hdr_len;
 208         pos = skb_push(skb, CCMP_HDR_LEN);
 209         memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
 210         pos += hdr_len;
 211         /* mic = skb_put(skb, CCMP_MIC_LEN); */
 212
 213         i = CCMP_PN_LEN - 1;
 214         while (i >= 0) {
 215                 key->tx_pn[i]++;
 216                 if (key->tx_pn[i] != 0)
 217                         break;
 218                 i--;
 219         }
 220
 221         *pos++ = key->tx_pn[5];
 222         *pos++ = key->tx_pn[4];
 223         *pos++ = 0;
 224         *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
 225         *pos++ = key->tx_pn[3];
 226         *pos++ = key->tx_pn[2];
 227         *pos++ = key->tx_pn[1];
 228         *pos++ = key->tx_pn[0];
 229
 230
 231         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 232         if (!tcb_desc->bHwSec)
 233         {
 234                 int blocks, last, len;
 235                 u8 *mic;
 236                 u8 *b0 = key->tx_b0;
 237                 u8 *b = key->tx_b;
 238                 u8 *e = key->tx_e;
 239                 u8 *s0 = key->tx_s0;
 240
 241                 /* mic is moved to here by john */
 242                 mic = skb_put(skb, CCMP_MIC_LEN);
 243
 244                 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
 245
 246                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 247                 last = data_len % AES_BLOCK_LEN;
 248
 249                 for (i = 1; i <= blocks; i++) {
 250                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 251                         /* Authentication */
 252                         xor_block(b, pos, len);
 253                         ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
 254                         /* Encryption, with counter */
 255                         b0[14] = (i >> 8) & 0xff;
 256                         b0[15] = i & 0xff;
 257                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
 258                         xor_block(pos, e, len);
 259                         pos += len;
 260                 }
 261
 262                 for (i = 0; i < CCMP_MIC_LEN; i++)
 263                         mic[i] = b[i] ^ s0[i];
 264         }
 265         return 0;
 266 }
 267
 268
 269 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 270 {
 271         struct ieee80211_ccmp_data *key = priv;
 272         u8 keyidx, *pos;
 273         struct ieee80211_hdr_4addr *hdr;
 274         cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 275         u8 pn[6];
 276
 277         if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
 278                 key->dot11RSNAStatsCCMPFormatErrors++;
 279                 return -1;
 280         }
 281
 282         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 283         pos = skb->data + hdr_len;
 284         keyidx = pos[3];
 285         if (!(keyidx & (1 << 5))) {
 286                 if (net_ratelimit()) {
 287                         printk(KERN_DEBUG "CCMP: received packet without ExtIV"
 288                                " flag from %pM\n", hdr->addr2);
 289                 }
 290                 key->dot11RSNAStatsCCMPFormatErrors++;
 291                 return -2;
 292         }
 293         keyidx >>= 6;
 294         if (key->key_idx != keyidx) {
 295                 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
 296                        "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
 297                 return -6;
 298         }
 299         if (!key->key_set) {
 300                 if (net_ratelimit()) {
 301                         printk(KERN_DEBUG "CCMP: received packet from %pM"
 302                                " with keyid=%d that does not have a configured"
 303                                " key\n", hdr->addr2, keyidx);
 304                 }
 305                 return -3;
 306         }
 307
 308         pn[0] = pos[7];
 309         pn[1] = pos[6];
 310         pn[2] = pos[5];
 311         pn[3] = pos[4];
 312         pn[4] = pos[1];
 313         pn[5] = pos[0];
 314         pos += 8;
 315
 316         if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
 317                 if (net_ratelimit()) {
 318                         printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
 319                                " previous PN %pm received PN %pm\n",
 320                                hdr->addr2, key->rx_pn, pn);
 321                 }
 322                 key->dot11RSNAStatsCCMPReplays++;
 323                 return -4;
 324         }
 325         if (!tcb_desc->bHwSec)
 326         {
 327                 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
 328                 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
 329                 u8 *b0 = key->rx_b0;
 330                 u8 *b = key->rx_b;
 331                 u8 *a = key->rx_a;
 332                 int i, blocks, last, len;
 333
 334
 335                 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
 336                 xor_block(mic, b, CCMP_MIC_LEN);
 337
 338                 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 339                 last = data_len % AES_BLOCK_LEN;
 340
 341                 for (i = 1; i <= blocks; i++) {
 342                         len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 343                         /* Decrypt, with counter */
 344                         b0[14] = (i >> 8) & 0xff;
 345                         b0[15] = i & 0xff;
 346                         ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
 347                         xor_block(pos, b, len);
 348                         /* Authentication */
 349                         xor_block(a, pos, len);
 350                         ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
 351                         pos += len;
 352                 }
 353
 354                 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
 355                         if (net_ratelimit()) {
 356                                 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
 357                                 "%pM\n", hdr->addr2);
 358                         }
 359                         key->dot11RSNAStatsCCMPDecryptErrors++;
 360                         return -5;
 361                 }
 362
 363                 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
 364         }
 365         /* Remove hdr and MIC */
 366         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
 367         skb_pull(skb, CCMP_HDR_LEN);
 368         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 369
 370         return keyidx;
 371 }
 372
 373
 374 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
 375 {
 376         struct ieee80211_ccmp_data *data = priv;
 377         int keyidx;
 378         struct crypto_tfm *tfm = data->tfm;
 379
 380         keyidx = data->key_idx;
 381         memset(data, 0, sizeof(*data));
 382         data->key_idx = keyidx;
 383         data->tfm = tfm;
 384         if (len == CCMP_TK_LEN) {
 385                 memcpy(data->key, key, CCMP_TK_LEN);
 386                 data->key_set = 1;
 387                 if (seq) {
 388                         data->rx_pn[0] = seq[5];
 389                         data->rx_pn[1] = seq[4];
 390                         data->rx_pn[2] = seq[3];
 391                         data->rx_pn[3] = seq[2];
 392                         data->rx_pn[4] = seq[1];
 393                         data->rx_pn[5] = seq[0];
 394                 }
 395                 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
 396         } else if (len == 0)
 397                 data->key_set = 0;
 398         else
 399                 return -1;
 400
 401         return 0;
 402 }
 403
 404
 405 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
 406 {
 407         struct ieee80211_ccmp_data *data = priv;
 408
 409         if (len < CCMP_TK_LEN)
 410                 return -1;
 411
 412         if (!data->key_set)
 413                 return 0;
 414         memcpy(key, data->key, CCMP_TK_LEN);
 415
 416         if (seq) {
 417                 seq[0] = data->tx_pn[5];
 418                 seq[1] = data->tx_pn[4];
 419                 seq[2] = data->tx_pn[3];
 420                 seq[3] = data->tx_pn[2];
 421                 seq[4] = data->tx_pn[1];
 422                 seq[5] = data->tx_pn[0];
 423         }
 424
 425         return CCMP_TK_LEN;
 426 }
 427
 428
 429 static char *ieee80211_ccmp_print_stats(char *p, void *priv)
 430 {
 431         struct ieee80211_ccmp_data *ccmp = priv;
 432         p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
 433                      "tx_pn=%pm rx_pn=%pm "
 434                      "format_errors=%d replays=%d decrypt_errors=%d\n",
 435                      ccmp->key_idx, ccmp->key_set,
 436                      ccmp->tx_pn, ccmp->rx_pn,
 437                      ccmp->dot11RSNAStatsCCMPFormatErrors,
 438                      ccmp->dot11RSNAStatsCCMPReplays,
 439                      ccmp->dot11RSNAStatsCCMPDecryptErrors);
 440
 441         return p;
 442 }
 443
 444 void ieee80211_ccmp_null(void)
 445 {
 446         /* printk("============>%s()\n", __func__); */
 447         return;
 448 }
 449
 450 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
 451         .name                   = "CCMP",
 452         .init                   = ieee80211_ccmp_init,
 453         .deinit                 = ieee80211_ccmp_deinit,
 454         .encrypt_mpdu           = ieee80211_ccmp_encrypt,
 455         .decrypt_mpdu           = ieee80211_ccmp_decrypt,
 456         .encrypt_msdu           = NULL,
 457         .decrypt_msdu           = NULL,
 458         .set_key                = ieee80211_ccmp_set_key,
 459         .get_key                = ieee80211_ccmp_get_key,
 460         .print_stats            = ieee80211_ccmp_print_stats,
 461         .extra_prefix_len       = CCMP_HDR_LEN,
 462         .extra_postfix_len      = CCMP_MIC_LEN,
 463         .owner                  = THIS_MODULE,
 464 };
 465
 466 int __init ieee80211_crypto_ccmp_init(void)
 467 {
 468         return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
 469 }
 470
 471 void __exit ieee80211_crypto_ccmp_exit(void)
 472 {
 473         ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
 474 }