SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/mac80211/wpa.c

   1 /*
   2  * Copyright 2002-2004, Instant802 Networks, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/netdevice.h>
  10 #include <linux/types.h>
  11 #include <linux/slab.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/compiler.h>
  14 #include <net/mac80211.h>
  15
  16 #include "ieee80211_i.h"
  17 #include "michael.h"
  18 #include "tkip.h"
  19 #include "aes_ccm.h"
  20 #include "wpa.h"
  21
  22 static int ieee80211_get_hdr_info(const struct sk_buff *skb, u8 **sa, u8 **da,
  23                                   u8 *qos_tid, u8 **data, size_t *data_len)
  24 {
  25         struct ieee80211_hdr *hdr;
  26         size_t hdrlen;
  27         u16 fc;
  28         int a4_included;
  29         u8 *pos;
  30
  31         hdr = (struct ieee80211_hdr *) skb->data;
  32         fc = le16_to_cpu(hdr->frame_control);
  33
  34         hdrlen = 24;
  35         if ((fc & (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) ==
  36             (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
  37                 hdrlen += ETH_ALEN;
  38                 *sa = hdr->addr4;
  39                 *da = hdr->addr3;
  40         } else if (fc & IEEE80211_FCTL_FROMDS) {
  41                 *sa = hdr->addr3;
  42                 *da = hdr->addr1;
  43         } else if (fc & IEEE80211_FCTL_TODS) {
  44                 *sa = hdr->addr2;
  45                 *da = hdr->addr3;
  46         } else {
  47                 *sa = hdr->addr2;
  48                 *da = hdr->addr1;
  49         }
  50
  51         if (fc & 0x80)
  52                 hdrlen += 2;
  53
  54         *data = skb->data + hdrlen;
  55         *data_len = skb->len - hdrlen;
  56
  57         a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
  58                 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
  59         if ((fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA &&
  60             fc & IEEE80211_STYPE_QOS_DATA) {
  61                 pos = (u8 *) &hdr->addr4;
  62                 if (a4_included)
  63                         pos += 6;
  64                 *qos_tid = pos[0] & 0x0f;
  65                 *qos_tid |= 0x80; /* qos_included flag */
  66         } else
  67                 *qos_tid = 0;
  68
  69         return skb->len < hdrlen ? -1 : 0;
  70 }
  71
  72
  73 ieee80211_txrx_result
  74 ieee80211_tx_h_michael_mic_add(struct ieee80211_txrx_data *tx)
  75 {
  76         u8 *data, *sa, *da, *key, *mic, qos_tid;
  77         size_t data_len;
  78         u16 fc;
  79         struct sk_buff *skb = tx->skb;
  80         int authenticator;
  81         int wpa_test = 0;
  82
  83         fc = tx->fc;
  84
  85         if (!tx->key || tx->key->conf.alg != ALG_TKIP || skb->len < 24 ||
  86             !WLAN_FC_DATA_PRESENT(fc))
  87                 return TXRX_CONTINUE;
  88
  89         if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len))
  90                 return TXRX_DROP;
  91
  92         if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
  93             !(tx->flags & IEEE80211_TXRXD_FRAGMENTED) &&
  94             !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) &&
  95             !wpa_test) {
  96                 /* hwaccel - with no need for preallocated room for Michael MIC
  97                  */
  98                 return TXRX_CONTINUE;
  99         }
 100
 101         if (skb_tailroom(skb) < MICHAEL_MIC_LEN) {
 102                 I802_DEBUG_INC(tx->local->tx_expand_skb_head);
 103                 if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN,
 104                                               MICHAEL_MIC_LEN + TKIP_ICV_LEN,
 105                                               GFP_ATOMIC))) {
 106                         printk(KERN_DEBUG "%s: failed to allocate more memory "
 107                                "for Michael MIC\n", tx->dev->name);
 108                         return TXRX_DROP;
 109                 }
 110         }
 111
 112 #if 0
 113         authenticator = fc & IEEE80211_FCTL_FROMDS; /* FIX */
 114 #else
 115         authenticator = 1;
 116 #endif
 117         key = &tx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_TX_MIC_KEY :
 118                                  ALG_TKIP_TEMP_AUTH_RX_MIC_KEY];
 119         mic = skb_put(skb, MICHAEL_MIC_LEN);
 120         michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
 121
 122         return TXRX_CONTINUE;
 123 }
 124
 125
 126 ieee80211_txrx_result
 127 ieee80211_rx_h_michael_mic_verify(struct ieee80211_txrx_data *rx)
 128 {
 129         u8 *data, *sa, *da, *key = NULL, qos_tid;
 130         size_t data_len;
 131         u16 fc;
 132         u8 mic[MICHAEL_MIC_LEN];
 133         struct sk_buff *skb = rx->skb;
 134         int authenticator = 1, wpa_test = 0;
 135
 136         fc = rx->fc;
 137
 138         /*
 139          * No way to verify the MIC if the hardware stripped it
 140          */
 141         if (rx->u.rx.status->flag & RX_FLAG_MMIC_STRIPPED)
 142                 return TXRX_CONTINUE;
 143
 144         if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
 145             !(rx->fc & IEEE80211_FCTL_PROTECTED) || !WLAN_FC_DATA_PRESENT(fc))
 146                 return TXRX_CONTINUE;
 147
 148         if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len)
 149             || data_len < MICHAEL_MIC_LEN)
 150                 return TXRX_DROP;
 151
 152         data_len -= MICHAEL_MIC_LEN;
 153
 154 #if 0
 155         authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
 156 #else
 157         authenticator = 1;
 158 #endif
 159         key = &rx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_RX_MIC_KEY :
 160                                  ALG_TKIP_TEMP_AUTH_TX_MIC_KEY];
 161         michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
 162         if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
 163                 if (!(rx->flags & IEEE80211_TXRXD_RXRA_MATCH))
 164                         return TXRX_DROP;
 165
 166                 printk(KERN_DEBUG "%s: invalid Michael MIC in data frame from "
 167                        MAC_FMT "\n", rx->dev->name, MAC_ARG(sa));
 168
 169                 mac80211_ev_michael_mic_failure(rx->dev, rx->key->conf.keyidx,
 170                                                 (void *) skb->data);
 171                 return TXRX_DROP;
 172         }
 173
 174         /* remove Michael MIC from payload */
 175         skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
 176
 177         return TXRX_CONTINUE;
 178 }
 179
 180
 181 static int tkip_encrypt_skb(struct ieee80211_txrx_data *tx,
 182                             struct sk_buff *skb, int test)
 183 {
 184         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 185         struct ieee80211_key *key = tx->key;
 186         int hdrlen, len, tailneed;
 187         u16 fc;
 188         u8 *pos;
 189
 190         fc = le16_to_cpu(hdr->frame_control);
 191         hdrlen = ieee80211_get_hdrlen(fc);
 192         len = skb->len - hdrlen;
 193
 194         if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
 195                 tailneed = 0;
 196         else
 197                 tailneed = TKIP_ICV_LEN;
 198
 199         if ((skb_headroom(skb) < TKIP_IV_LEN ||
 200              skb_tailroom(skb) < tailneed)) {
 201                 I802_DEBUG_INC(tx->local->tx_expand_skb_head);
 202                 if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN, tailneed,
 203                                               GFP_ATOMIC)))
 204                         return -1;
 205         }
 206
 207         pos = skb_push(skb, TKIP_IV_LEN);
 208         memmove(pos, pos + TKIP_IV_LEN, hdrlen);
 209         pos += hdrlen;
 210
 211         /* Increase IV for the frame */
 212         key->u.tkip.iv16++;
 213         if (key->u.tkip.iv16 == 0)
 214                 key->u.tkip.iv32++;
 215
 216         if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
 217                 u32 flags = tx->local->hw.flags;
 218                 hdr = (struct ieee80211_hdr *)skb->data;
 219
 220                 /* hwaccel - with preallocated room for IV */
 221                 ieee80211_tkip_add_iv(pos, key,
 222                                       (u8) (key->u.tkip.iv16 >> 8),
 223                                       (u8) (((key->u.tkip.iv16 >> 8) | 0x20) &
 224                                             0x7f),
 225                                       (u8) key->u.tkip.iv16);
 226
 227                 if (flags & IEEE80211_HW_TKIP_REQ_PHASE2_KEY)
 228                         ieee80211_tkip_gen_rc4key(key, hdr->addr2,
 229                                                   tx->u.tx.control->tkip_key);
 230                 else if (flags & IEEE80211_HW_TKIP_REQ_PHASE1_KEY) {
 231                         if (key->u.tkip.iv16 == 0 ||
 232                             !key->u.tkip.tx_initialized) {
 233                                 ieee80211_tkip_gen_phase1key(key, hdr->addr2,
 234                                             (u16 *)tx->u.tx.control->tkip_key);
 235                                 key->u.tkip.tx_initialized = 1;
 236                                 tx->u.tx.control->flags |=
 237                                             IEEE80211_TXCTL_TKIP_NEW_PHASE1_KEY;
 238                         } else
 239                                 tx->u.tx.control->flags &=
 240                                             ~IEEE80211_TXCTL_TKIP_NEW_PHASE1_KEY;
 241                 }
 242
 243                 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
 244                 return 0;
 245         }
 246
 247         /* Add room for ICV */
 248         skb_put(skb, TKIP_ICV_LEN);
 249
 250         hdr = (struct ieee80211_hdr *) skb->data;
 251         ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
 252                                     key, pos, len, hdr->addr2);
 253         return 0;
 254 }
 255
 256
 257 ieee80211_txrx_result
 258 ieee80211_tx_h_tkip_encrypt(struct ieee80211_txrx_data *tx)
 259 {
 260         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 261         u16 fc;
 262         struct ieee80211_key *key = tx->key;
 263         struct sk_buff *skb = tx->skb;
 264         int wpa_test = 0, test = 0;
 265
 266         fc = le16_to_cpu(hdr->frame_control);
 267
 268         if (!key || key->conf.alg != ALG_TKIP || !WLAN_FC_DATA_PRESENT(fc))
 269                 return TXRX_CONTINUE;
 270
 271         tx->u.tx.control->icv_len = TKIP_ICV_LEN;
 272         tx->u.tx.control->iv_len = TKIP_IV_LEN;
 273         ieee80211_tx_set_iswep(tx);
 274
 275         if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 276             !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 277             !wpa_test) {
 278                 /* hwaccel - with no need for preallocated room for IV/ICV */
 279                 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
 280                 return TXRX_CONTINUE;
 281         }
 282
 283         if (tkip_encrypt_skb(tx, skb, test) < 0)
 284                 return TXRX_DROP;
 285
 286         if (tx->u.tx.extra_frag) {
 287                 int i;
 288                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 289                         if (tkip_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
 290                             < 0)
 291                                 return TXRX_DROP;
 292                 }
 293         }
 294
 295         return TXRX_CONTINUE;
 296 }
 297
 298
 299 ieee80211_txrx_result
 300 ieee80211_rx_h_tkip_decrypt(struct ieee80211_txrx_data *rx)
 301 {
 302         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 303         u16 fc;
 304         int hdrlen, res, hwaccel = 0, wpa_test = 0;
 305         struct ieee80211_key *key = rx->key;
 306         struct sk_buff *skb = rx->skb;
 307
 308         fc = le16_to_cpu(hdr->frame_control);
 309         hdrlen = ieee80211_get_hdrlen(fc);
 310
 311         if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
 312             !(rx->fc & IEEE80211_FCTL_PROTECTED) ||
 313             (rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
 314                 return TXRX_CONTINUE;
 315
 316         if (!rx->sta || skb->len - hdrlen < 12)
 317                 return TXRX_DROP;
 318
 319         if (rx->u.rx.status->flag & RX_FLAG_DECRYPTED) {
 320                 if (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED) {
 321                         /*
 322                          * Hardware took care of all processing, including
 323                          * replay protection, and stripped the ICV/IV so
 324                          * we cannot do any checks here.
 325                          */
 326                         return TXRX_CONTINUE;
 327                 }
 328
 329                 /* let TKIP code verify IV, but skip decryption */
 330                 hwaccel = 1;
 331         }
 332
 333         res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
 334                                           key, skb->data + hdrlen,
 335                                           skb->len - hdrlen, rx->sta->addr,
 336                                           hwaccel, rx->u.rx.queue);
 337         if (res != TKIP_DECRYPT_OK || wpa_test) {
 338                 printk(KERN_DEBUG "%s: TKIP decrypt failed for RX frame from "
 339                        MAC_FMT " (res=%d)\n",
 340                        rx->dev->name, MAC_ARG(rx->sta->addr), res);
 341                 return TXRX_DROP;
 342         }
 343
 344         /* Trim ICV */
 345         skb_trim(skb, skb->len - TKIP_ICV_LEN);
 346
 347         /* Remove IV */
 348         memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
 349         skb_pull(skb, TKIP_IV_LEN);
 350
 351         return TXRX_CONTINUE;
 352 }
 353
 354
 355 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
 356                                 int encrypted)
 357 {
 358         u16 fc;
 359         int a4_included, qos_included;
 360         u8 qos_tid, *fc_pos, *data, *sa, *da;
 361         int len_a;
 362         size_t data_len;
 363         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 364
 365         fc_pos = (u8 *) &hdr->frame_control;
 366         fc = fc_pos[0] ^ (fc_pos[1] << 8);
 367         a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 368                 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
 369
 370         ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len);
 371         data_len -= CCMP_HDR_LEN + (encrypted ? CCMP_MIC_LEN : 0);
 372         if (qos_tid & 0x80) {
 373                 qos_included = 1;
 374                 qos_tid &= 0x0f;
 375         } else
 376                 qos_included = 0;
 377         /* First block, b_0 */
 378
 379         b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
 380         /* Nonce: QoS Priority | A2 | PN */
 381         b_0[1] = qos_tid;
 382         memcpy(&b_0[2], hdr->addr2, 6);
 383         memcpy(&b_0[8], pn, CCMP_PN_LEN);
 384         /* l(m) */
 385         b_0[14] = (data_len >> 8) & 0xff;
 386         b_0[15] = data_len & 0xff;
 387
 388
 389         /* AAD (extra authenticate-only data) / masked 802.11 header
 390          * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
 391
 392         len_a = a4_included ? 28 : 22;
 393         if (qos_included)
 394                 len_a += 2;
 395
 396         aad[0] = 0; /* (len_a >> 8) & 0xff; */
 397         aad[1] = len_a & 0xff;
 398         /* Mask FC: zero subtype b4 b5 b6 */
 399         aad[2] = fc_pos[0] & ~(BIT(4) | BIT(5) | BIT(6));
 400         /* Retry, PwrMgt, MoreData; set Protected */
 401         aad[3] = (fc_pos[1] & ~(BIT(3) | BIT(4) | BIT(5))) | BIT(6);
 402         memcpy(&aad[4], &hdr->addr1, 18);
 403
 404         /* Mask Seq#, leave Frag# */
 405         aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
 406         aad[23] = 0;
 407         if (a4_included) {
 408                 memcpy(&aad[24], hdr->addr4, 6);
 409                 aad[30] = 0;
 410                 aad[31] = 0;
 411         } else
 412                 memset(&aad[24], 0, 8);
 413         if (qos_included) {
 414                 u8 *dpos = &aad[a4_included ? 30 : 24];
 415
 416                 /* Mask QoS Control field */
 417                 dpos[0] = qos_tid;
 418                 dpos[1] = 0;
 419         }
 420 }
 421
 422
 423 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
 424 {
 425         hdr[0] = pn[5];
 426         hdr[1] = pn[4];
 427         hdr[2] = 0;
 428         hdr[3] = 0x20 | (key_id << 6);
 429         hdr[4] = pn[3];
 430         hdr[5] = pn[2];
 431         hdr[6] = pn[1];
 432         hdr[7] = pn[0];
 433 }
 434
 435
 436 static inline int ccmp_hdr2pn(u8 *pn, u8 *hdr)
 437 {
 438         pn[0] = hdr[7];
 439         pn[1] = hdr[6];
 440         pn[2] = hdr[5];
 441         pn[3] = hdr[4];
 442         pn[4] = hdr[1];
 443         pn[5] = hdr[0];
 444         return (hdr[3] >> 6) & 0x03;
 445 }
 446
 447
 448 static int ccmp_encrypt_skb(struct ieee80211_txrx_data *tx,
 449                             struct sk_buff *skb, int test)
 450 {
 451         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 452         struct ieee80211_key *key = tx->key;
 453         int hdrlen, len, tailneed;
 454         u16 fc;
 455         u8 *pos, *pn, *b_0, *aad, *scratch;
 456         int i;
 457
 458         scratch = key->u.ccmp.tx_crypto_buf;
 459         b_0 = scratch + 3 * AES_BLOCK_LEN;
 460         aad = scratch + 4 * AES_BLOCK_LEN;
 461
 462         fc = le16_to_cpu(hdr->frame_control);
 463         hdrlen = ieee80211_get_hdrlen(fc);
 464         len = skb->len - hdrlen;
 465
 466         if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
 467                 tailneed = 0;
 468         else
 469                 tailneed = CCMP_MIC_LEN;
 470
 471         if ((skb_headroom(skb) < CCMP_HDR_LEN ||
 472              skb_tailroom(skb) < tailneed)) {
 473                 I802_DEBUG_INC(tx->local->tx_expand_skb_head);
 474                 if (unlikely(pskb_expand_head(skb, CCMP_HDR_LEN, tailneed,
 475                                               GFP_ATOMIC)))
 476                         return -1;
 477         }
 478
 479         pos = skb_push(skb, CCMP_HDR_LEN);
 480         memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
 481         hdr = (struct ieee80211_hdr *) pos;
 482         pos += hdrlen;
 483
 484         /* PN = PN + 1 */
 485         pn = key->u.ccmp.tx_pn;
 486
 487         for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
 488                 pn[i]++;
 489                 if (pn[i])
 490                         break;
 491         }
 492
 493         ccmp_pn2hdr(pos, pn, key->conf.keyidx);
 494
 495         if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
 496                 /* hwaccel - with preallocated room for CCMP header */
 497                 tx->u.tx.control->key_idx = key->conf.hw_key_idx;
 498                 return 0;
 499         }
 500
 501         pos += CCMP_HDR_LEN;
 502         ccmp_special_blocks(skb, pn, b_0, aad, 0);
 503         ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, b_0, aad, pos, len,
 504                                   pos, skb_put(skb, CCMP_MIC_LEN));
 505
 506         return 0;
 507 }
 508
 509
 510 ieee80211_txrx_result
 511 ieee80211_tx_h_ccmp_encrypt(struct ieee80211_txrx_data *tx)
 512 {
 513         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 514         struct ieee80211_key *key = tx->key;
 515         u16 fc;
 516         struct sk_buff *skb = tx->skb;
 517         int test = 0;
 518
 519         fc = le16_to_cpu(hdr->frame_control);
 520
 521         if (!key || key->conf.alg != ALG_CCMP || !WLAN_FC_DATA_PRESENT(fc))
 522                 return TXRX_CONTINUE;
 523
 524         tx->u.tx.control->icv_len = CCMP_MIC_LEN;
 525         tx->u.tx.control->iv_len = CCMP_HDR_LEN;
 526         ieee80211_tx_set_iswep(tx);
 527
 528         if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 529             !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
 530                 /* hwaccel - with no need for preallocated room for CCMP "
 531                  * header or MIC fields */
 532                 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
 533                 return TXRX_CONTINUE;
 534         }
 535
 536         if (ccmp_encrypt_skb(tx, skb, test) < 0)
 537                 return TXRX_DROP;
 538
 539         if (tx->u.tx.extra_frag) {
 540                 int i;
 541                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 542                         if (ccmp_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
 543                             < 0)
 544                                 return TXRX_DROP;
 545                 }
 546         }
 547
 548         return TXRX_CONTINUE;
 549 }
 550
 551
 552 ieee80211_txrx_result
 553 ieee80211_rx_h_ccmp_decrypt(struct ieee80211_txrx_data *rx)
 554 {
 555         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 556         u16 fc;
 557         int hdrlen;
 558         struct ieee80211_key *key = rx->key;
 559         struct sk_buff *skb = rx->skb;
 560         u8 pn[CCMP_PN_LEN];
 561         int data_len;
 562
 563         fc = le16_to_cpu(hdr->frame_control);
 564         hdrlen = ieee80211_get_hdrlen(fc);
 565
 566         if (!key || key->conf.alg != ALG_CCMP ||
 567             !(rx->fc & IEEE80211_FCTL_PROTECTED) ||
 568             (rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
 569                 return TXRX_CONTINUE;
 570
 571         data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
 572         if (!rx->sta || data_len < 0)
 573                 return TXRX_DROP;
 574
 575         if ((rx->u.rx.status->flag & RX_FLAG_DECRYPTED) &&
 576             (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED))
 577                 return TXRX_CONTINUE;
 578
 579         (void) ccmp_hdr2pn(pn, skb->data + hdrlen);
 580
 581         if (memcmp(pn, key->u.ccmp.rx_pn[rx->u.rx.queue], CCMP_PN_LEN) <= 0) {
 582 #ifdef CONFIG_MAC80211_DEBUG
 583                 u8 *ppn = key->u.ccmp.rx_pn[rx->u.rx.queue];
 584                 printk(KERN_DEBUG "%s: CCMP replay detected for RX frame from "
 585                        MAC_FMT " (RX PN %02x%02x%02x%02x%02x%02x <= prev. PN "
 586                        "%02x%02x%02x%02x%02x%02x)\n", rx->dev->name,
 587                        MAC_ARG(rx->sta->addr),
 588                        pn[0], pn[1], pn[2], pn[3], pn[4], pn[5],
 589                        ppn[0], ppn[1], ppn[2], ppn[3], ppn[4], ppn[5]);
 590 #endif /* CONFIG_MAC80211_DEBUG */
 591                 key->u.ccmp.replays++;
 592                 return TXRX_DROP;
 593         }
 594
 595         if (!(rx->u.rx.status->flag & RX_FLAG_DECRYPTED)) {
 596                 /* hardware didn't decrypt/verify MIC */
 597                 u8 *scratch, *b_0, *aad;
 598
 599                 scratch = key->u.ccmp.rx_crypto_buf;
 600                 b_0 = scratch + 3 * AES_BLOCK_LEN;
 601                 aad = scratch + 4 * AES_BLOCK_LEN;
 602
 603                 ccmp_special_blocks(skb, pn, b_0, aad, 1);
 604
 605                 if (ieee80211_aes_ccm_decrypt(
 606                             key->u.ccmp.tfm, scratch, b_0, aad,
 607                             skb->data + hdrlen + CCMP_HDR_LEN, data_len,
 608                             skb->data + skb->len - CCMP_MIC_LEN,
 609                             skb->data + hdrlen + CCMP_HDR_LEN)) {
 610                         printk(KERN_DEBUG "%s: CCMP decrypt failed for RX "
 611                                "frame from " MAC_FMT "\n", rx->dev->name,
 612                                MAC_ARG(rx->sta->addr));
 613                         return TXRX_DROP;
 614                 }
 615         }
 616
 617         memcpy(key->u.ccmp.rx_pn[rx->u.rx.queue], pn, CCMP_PN_LEN);
 618
 619         /* Remove CCMP header and MIC */
 620         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 621         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
 622         skb_pull(skb, CCMP_HDR_LEN);
 623
 624         return TXRX_CONTINUE;
 625 }
 626