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                 hdr = (struct ieee80211_hdr *)skb->data;
 218
 219                 /* hwaccel - with preallocated room for IV */
 220                 ieee80211_tkip_add_iv(pos, key,
 221                                       (u8) (key->u.tkip.iv16 >> 8),
 222                                       (u8) (((key->u.tkip.iv16 >> 8) | 0x20) &
 223                                             0x7f),
 224                                       (u8) key->u.tkip.iv16);
 225
 226                 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
 227                 return 0;
 228         }
 229
 230         /* Add room for ICV */
 231         skb_put(skb, TKIP_ICV_LEN);
 232
 233         hdr = (struct ieee80211_hdr *) skb->data;
 234         ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
 235                                     key, pos, len, hdr->addr2);
 236         return 0;
 237 }
 238
 239
 240 ieee80211_txrx_result
 241 ieee80211_tx_h_tkip_encrypt(struct ieee80211_txrx_data *tx)
 242 {
 243         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 244         u16 fc;
 245         struct ieee80211_key *key = tx->key;
 246         struct sk_buff *skb = tx->skb;
 247         int wpa_test = 0, test = 0;
 248
 249         fc = le16_to_cpu(hdr->frame_control);
 250
 251         if (!key || key->conf.alg != ALG_TKIP || !WLAN_FC_DATA_PRESENT(fc))
 252                 return TXRX_CONTINUE;
 253
 254         tx->u.tx.control->icv_len = TKIP_ICV_LEN;
 255         tx->u.tx.control->iv_len = TKIP_IV_LEN;
 256         ieee80211_tx_set_iswep(tx);
 257
 258         if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 259             !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 260             !wpa_test) {
 261                 /* hwaccel - with no need for preallocated room for IV/ICV */
 262                 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
 263                 return TXRX_CONTINUE;
 264         }
 265
 266         if (tkip_encrypt_skb(tx, skb, test) < 0)
 267                 return TXRX_DROP;
 268
 269         if (tx->u.tx.extra_frag) {
 270                 int i;
 271                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 272                         if (tkip_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
 273                             < 0)
 274                                 return TXRX_DROP;
 275                 }
 276         }
 277
 278         return TXRX_CONTINUE;
 279 }
 280
 281
 282 ieee80211_txrx_result
 283 ieee80211_rx_h_tkip_decrypt(struct ieee80211_txrx_data *rx)
 284 {
 285         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 286         u16 fc;
 287         int hdrlen, res, hwaccel = 0, wpa_test = 0;
 288         struct ieee80211_key *key = rx->key;
 289         struct sk_buff *skb = rx->skb;
 290
 291         fc = le16_to_cpu(hdr->frame_control);
 292         hdrlen = ieee80211_get_hdrlen(fc);
 293
 294         if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
 295             !(rx->fc & IEEE80211_FCTL_PROTECTED) ||
 296             (rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
 297                 return TXRX_CONTINUE;
 298
 299         if (!rx->sta || skb->len - hdrlen < 12)
 300                 return TXRX_DROP;
 301
 302         if (rx->u.rx.status->flag & RX_FLAG_DECRYPTED) {
 303                 if (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED) {
 304                         /*
 305                          * Hardware took care of all processing, including
 306                          * replay protection, and stripped the ICV/IV so
 307                          * we cannot do any checks here.
 308                          */
 309                         return TXRX_CONTINUE;
 310                 }
 311
 312                 /* let TKIP code verify IV, but skip decryption */
 313                 hwaccel = 1;
 314         }
 315
 316         res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
 317                                           key, skb->data + hdrlen,
 318                                           skb->len - hdrlen, rx->sta->addr,
 319                                           hwaccel, rx->u.rx.queue);
 320         if (res != TKIP_DECRYPT_OK || wpa_test) {
 321                 printk(KERN_DEBUG "%s: TKIP decrypt failed for RX frame from "
 322                        MAC_FMT " (res=%d)\n",
 323                        rx->dev->name, MAC_ARG(rx->sta->addr), res);
 324                 return TXRX_DROP;
 325         }
 326
 327         /* Trim ICV */
 328         skb_trim(skb, skb->len - TKIP_ICV_LEN);
 329
 330         /* Remove IV */
 331         memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
 332         skb_pull(skb, TKIP_IV_LEN);
 333
 334         return TXRX_CONTINUE;
 335 }
 336
 337
 338 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
 339                                 int encrypted)
 340 {
 341         u16 fc;
 342         int a4_included, qos_included;
 343         u8 qos_tid, *fc_pos, *data, *sa, *da;
 344         int len_a;
 345         size_t data_len;
 346         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 347
 348         fc_pos = (u8 *) &hdr->frame_control;
 349         fc = fc_pos[0] ^ (fc_pos[1] << 8);
 350         a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 351                 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
 352
 353         ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len);
 354         data_len -= CCMP_HDR_LEN + (encrypted ? CCMP_MIC_LEN : 0);
 355         if (qos_tid & 0x80) {
 356                 qos_included = 1;
 357                 qos_tid &= 0x0f;
 358         } else
 359                 qos_included = 0;
 360         /* First block, b_0 */
 361
 362         b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
 363         /* Nonce: QoS Priority | A2 | PN */
 364         b_0[1] = qos_tid;
 365         memcpy(&b_0[2], hdr->addr2, 6);
 366         memcpy(&b_0[8], pn, CCMP_PN_LEN);
 367         /* l(m) */
 368         b_0[14] = (data_len >> 8) & 0xff;
 369         b_0[15] = data_len & 0xff;
 370
 371
 372         /* AAD (extra authenticate-only data) / masked 802.11 header
 373          * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
 374
 375         len_a = a4_included ? 28 : 22;
 376         if (qos_included)
 377                 len_a += 2;
 378
 379         aad[0] = 0; /* (len_a >> 8) & 0xff; */
 380         aad[1] = len_a & 0xff;
 381         /* Mask FC: zero subtype b4 b5 b6 */
 382         aad[2] = fc_pos[0] & ~(BIT(4) | BIT(5) | BIT(6));
 383         /* Retry, PwrMgt, MoreData; set Protected */
 384         aad[3] = (fc_pos[1] & ~(BIT(3) | BIT(4) | BIT(5))) | BIT(6);
 385         memcpy(&aad[4], &hdr->addr1, 18);
 386
 387         /* Mask Seq#, leave Frag# */
 388         aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
 389         aad[23] = 0;
 390         if (a4_included) {
 391                 memcpy(&aad[24], hdr->addr4, 6);
 392                 aad[30] = 0;
 393                 aad[31] = 0;
 394         } else
 395                 memset(&aad[24], 0, 8);
 396         if (qos_included) {
 397                 u8 *dpos = &aad[a4_included ? 30 : 24];
 398
 399                 /* Mask QoS Control field */
 400                 dpos[0] = qos_tid;
 401                 dpos[1] = 0;
 402         }
 403 }
 404
 405
 406 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
 407 {
 408         hdr[0] = pn[5];
 409         hdr[1] = pn[4];
 410         hdr[2] = 0;
 411         hdr[3] = 0x20 | (key_id << 6);
 412         hdr[4] = pn[3];
 413         hdr[5] = pn[2];
 414         hdr[6] = pn[1];
 415         hdr[7] = pn[0];
 416 }
 417
 418
 419 static inline int ccmp_hdr2pn(u8 *pn, u8 *hdr)
 420 {
 421         pn[0] = hdr[7];
 422         pn[1] = hdr[6];
 423         pn[2] = hdr[5];
 424         pn[3] = hdr[4];
 425         pn[4] = hdr[1];
 426         pn[5] = hdr[0];
 427         return (hdr[3] >> 6) & 0x03;
 428 }
 429
 430
 431 static int ccmp_encrypt_skb(struct ieee80211_txrx_data *tx,
 432                             struct sk_buff *skb, int test)
 433 {
 434         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 435         struct ieee80211_key *key = tx->key;
 436         int hdrlen, len, tailneed;
 437         u16 fc;
 438         u8 *pos, *pn, *b_0, *aad, *scratch;
 439         int i;
 440
 441         scratch = key->u.ccmp.tx_crypto_buf;
 442         b_0 = scratch + 3 * AES_BLOCK_LEN;
 443         aad = scratch + 4 * AES_BLOCK_LEN;
 444
 445         fc = le16_to_cpu(hdr->frame_control);
 446         hdrlen = ieee80211_get_hdrlen(fc);
 447         len = skb->len - hdrlen;
 448
 449         if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
 450                 tailneed = 0;
 451         else
 452                 tailneed = CCMP_MIC_LEN;
 453
 454         if ((skb_headroom(skb) < CCMP_HDR_LEN ||
 455              skb_tailroom(skb) < tailneed)) {
 456                 I802_DEBUG_INC(tx->local->tx_expand_skb_head);
 457                 if (unlikely(pskb_expand_head(skb, CCMP_HDR_LEN, tailneed,
 458                                               GFP_ATOMIC)))
 459                         return -1;
 460         }
 461
 462         pos = skb_push(skb, CCMP_HDR_LEN);
 463         memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
 464         hdr = (struct ieee80211_hdr *) pos;
 465         pos += hdrlen;
 466
 467         /* PN = PN + 1 */
 468         pn = key->u.ccmp.tx_pn;
 469
 470         for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
 471                 pn[i]++;
 472                 if (pn[i])
 473                         break;
 474         }
 475
 476         ccmp_pn2hdr(pos, pn, key->conf.keyidx);
 477
 478         if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
 479                 /* hwaccel - with preallocated room for CCMP header */
 480                 tx->u.tx.control->key_idx = key->conf.hw_key_idx;
 481                 return 0;
 482         }
 483
 484         pos += CCMP_HDR_LEN;
 485         ccmp_special_blocks(skb, pn, b_0, aad, 0);
 486         ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, b_0, aad, pos, len,
 487                                   pos, skb_put(skb, CCMP_MIC_LEN));
 488
 489         return 0;
 490 }
 491
 492
 493 ieee80211_txrx_result
 494 ieee80211_tx_h_ccmp_encrypt(struct ieee80211_txrx_data *tx)
 495 {
 496         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 497         struct ieee80211_key *key = tx->key;
 498         u16 fc;
 499         struct sk_buff *skb = tx->skb;
 500         int test = 0;
 501
 502         fc = le16_to_cpu(hdr->frame_control);
 503
 504         if (!key || key->conf.alg != ALG_CCMP || !WLAN_FC_DATA_PRESENT(fc))
 505                 return TXRX_CONTINUE;
 506
 507         tx->u.tx.control->icv_len = CCMP_MIC_LEN;
 508         tx->u.tx.control->iv_len = CCMP_HDR_LEN;
 509         ieee80211_tx_set_iswep(tx);
 510
 511         if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 512             !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
 513                 /* hwaccel - with no need for preallocated room for CCMP "
 514                  * header or MIC fields */
 515                 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
 516                 return TXRX_CONTINUE;
 517         }
 518
 519         if (ccmp_encrypt_skb(tx, skb, test) < 0)
 520                 return TXRX_DROP;
 521
 522         if (tx->u.tx.extra_frag) {
 523                 int i;
 524                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 525                         if (ccmp_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
 526                             < 0)
 527                                 return TXRX_DROP;
 528                 }
 529         }
 530
 531         return TXRX_CONTINUE;
 532 }
 533
 534
 535 ieee80211_txrx_result
 536 ieee80211_rx_h_ccmp_decrypt(struct ieee80211_txrx_data *rx)
 537 {
 538         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 539         u16 fc;
 540         int hdrlen;
 541         struct ieee80211_key *key = rx->key;
 542         struct sk_buff *skb = rx->skb;
 543         u8 pn[CCMP_PN_LEN];
 544         int data_len;
 545
 546         fc = le16_to_cpu(hdr->frame_control);
 547         hdrlen = ieee80211_get_hdrlen(fc);
 548
 549         if (!key || key->conf.alg != ALG_CCMP ||
 550             !(rx->fc & IEEE80211_FCTL_PROTECTED) ||
 551             (rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
 552                 return TXRX_CONTINUE;
 553
 554         data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
 555         if (!rx->sta || data_len < 0)
 556                 return TXRX_DROP;
 557
 558         if ((rx->u.rx.status->flag & RX_FLAG_DECRYPTED) &&
 559             (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED))
 560                 return TXRX_CONTINUE;
 561
 562         (void) ccmp_hdr2pn(pn, skb->data + hdrlen);
 563
 564         if (memcmp(pn, key->u.ccmp.rx_pn[rx->u.rx.queue], CCMP_PN_LEN) <= 0) {
 565 #ifdef CONFIG_MAC80211_DEBUG
 566                 u8 *ppn = key->u.ccmp.rx_pn[rx->u.rx.queue];
 567                 printk(KERN_DEBUG "%s: CCMP replay detected for RX frame from "
 568                        MAC_FMT " (RX PN %02x%02x%02x%02x%02x%02x <= prev. PN "
 569                        "%02x%02x%02x%02x%02x%02x)\n", rx->dev->name,
 570                        MAC_ARG(rx->sta->addr),
 571                        pn[0], pn[1], pn[2], pn[3], pn[4], pn[5],
 572                        ppn[0], ppn[1], ppn[2], ppn[3], ppn[4], ppn[5]);
 573 #endif /* CONFIG_MAC80211_DEBUG */
 574                 key->u.ccmp.replays++;
 575                 return TXRX_DROP;
 576         }
 577
 578         if (!(rx->u.rx.status->flag & RX_FLAG_DECRYPTED)) {
 579                 /* hardware didn't decrypt/verify MIC */
 580                 u8 *scratch, *b_0, *aad;
 581
 582                 scratch = key->u.ccmp.rx_crypto_buf;
 583                 b_0 = scratch + 3 * AES_BLOCK_LEN;
 584                 aad = scratch + 4 * AES_BLOCK_LEN;
 585
 586                 ccmp_special_blocks(skb, pn, b_0, aad, 1);
 587
 588                 if (ieee80211_aes_ccm_decrypt(
 589                             key->u.ccmp.tfm, scratch, b_0, aad,
 590                             skb->data + hdrlen + CCMP_HDR_LEN, data_len,
 591                             skb->data + skb->len - CCMP_MIC_LEN,
 592                             skb->data + hdrlen + CCMP_HDR_LEN)) {
 593                         printk(KERN_DEBUG "%s: CCMP decrypt failed for RX "
 594                                "frame from " MAC_FMT "\n", rx->dev->name,
 595                                MAC_ARG(rx->sta->addr));
 596                         return TXRX_DROP;
 597                 }
 598         }
 599
 600         memcpy(key->u.ccmp.rx_pn[rx->u.rx.queue], pn, CCMP_PN_LEN);
 601
 602         /* Remove CCMP header and MIC */
 603         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 604         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
 605         skb_pull(skb, CCMP_HDR_LEN);
 606
 607         return TXRX_CONTINUE;
 608 }
 609