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         DECLARE_MAC_BUF(mac);
 136
 137         fc = rx->fc;
 138
 139         /*
 140          * No way to verify the MIC if the hardware stripped it
 141          */
 142         if (rx->u.rx.status->flag & RX_FLAG_MMIC_STRIPPED)
 143                 return TXRX_CONTINUE;
 144
 145         if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
 146             !(rx->fc & IEEE80211_FCTL_PROTECTED) || !WLAN_FC_DATA_PRESENT(fc))
 147                 return TXRX_CONTINUE;
 148
 149         if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len)
 150             || data_len < MICHAEL_MIC_LEN)
 151                 return TXRX_DROP;
 152
 153         data_len -= MICHAEL_MIC_LEN;
 154
 155 #if 0
 156         authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
 157 #else
 158         authenticator = 1;
 159 #endif
 160         key = &rx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_RX_MIC_KEY :
 161                                  ALG_TKIP_TEMP_AUTH_TX_MIC_KEY];
 162         michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
 163         if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
 164                 if (!(rx->flags & IEEE80211_TXRXD_RXRA_MATCH))
 165                         return TXRX_DROP;
 166
 167                 printk(KERN_DEBUG "%s: invalid Michael MIC in data frame from "
 168                        "%s\n", rx->dev->name, print_mac(mac, sa));
 169
 170                 mac80211_ev_michael_mic_failure(rx->dev, rx->key->conf.keyidx,
 171                                                 (void *) skb->data);
 172                 return TXRX_DROP;
 173         }
 174
 175         /* remove Michael MIC from payload */
 176         skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
 177
 178         /* update IV in key information to be able to detect replays */
 179         rx->key->u.tkip.iv32_rx[rx->u.rx.queue] = rx->u.rx.tkip_iv32;
 180         rx->key->u.tkip.iv16_rx[rx->u.rx.queue] = rx->u.rx.tkip_iv16;
 181
 182         return TXRX_CONTINUE;
 183 }
 184
 185
 186 static int tkip_encrypt_skb(struct ieee80211_txrx_data *tx,
 187                             struct sk_buff *skb, int test)
 188 {
 189         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 190         struct ieee80211_key *key = tx->key;
 191         int hdrlen, len, tailneed;
 192         u16 fc;
 193         u8 *pos;
 194
 195         fc = le16_to_cpu(hdr->frame_control);
 196         hdrlen = ieee80211_get_hdrlen(fc);
 197         len = skb->len - hdrlen;
 198
 199         if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
 200                 tailneed = 0;
 201         else
 202                 tailneed = TKIP_ICV_LEN;
 203
 204         if ((skb_headroom(skb) < TKIP_IV_LEN ||
 205              skb_tailroom(skb) < tailneed)) {
 206                 I802_DEBUG_INC(tx->local->tx_expand_skb_head);
 207                 if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN, tailneed,
 208                                               GFP_ATOMIC)))
 209                         return -1;
 210         }
 211
 212         pos = skb_push(skb, TKIP_IV_LEN);
 213         memmove(pos, pos + TKIP_IV_LEN, hdrlen);
 214         pos += hdrlen;
 215
 216         /* Increase IV for the frame */
 217         key->u.tkip.iv16++;
 218         if (key->u.tkip.iv16 == 0)
 219                 key->u.tkip.iv32++;
 220
 221         if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
 222                 hdr = (struct ieee80211_hdr *)skb->data;
 223
 224                 /* hwaccel - with preallocated room for IV */
 225                 ieee80211_tkip_add_iv(pos, key,
 226                                       (u8) (key->u.tkip.iv16 >> 8),
 227                                       (u8) (((key->u.tkip.iv16 >> 8) | 0x20) &
 228                                             0x7f),
 229                                       (u8) key->u.tkip.iv16);
 230
 231                 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
 232                 return 0;
 233         }
 234
 235         /* Add room for ICV */
 236         skb_put(skb, TKIP_ICV_LEN);
 237
 238         hdr = (struct ieee80211_hdr *) skb->data;
 239         ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
 240                                     key, pos, len, hdr->addr2);
 241         return 0;
 242 }
 243
 244
 245 ieee80211_txrx_result
 246 ieee80211_crypto_tkip_encrypt(struct ieee80211_txrx_data *tx)
 247 {
 248         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 249         u16 fc;
 250         struct sk_buff *skb = tx->skb;
 251         int wpa_test = 0, test = 0;
 252
 253         fc = le16_to_cpu(hdr->frame_control);
 254
 255         if (!WLAN_FC_DATA_PRESENT(fc))
 256                 return TXRX_CONTINUE;
 257
 258         tx->u.tx.control->icv_len = TKIP_ICV_LEN;
 259         tx->u.tx.control->iv_len = TKIP_IV_LEN;
 260         ieee80211_tx_set_iswep(tx);
 261
 262         if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 263             !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 264             !wpa_test) {
 265                 /* hwaccel - with no need for preallocated room for IV/ICV */
 266                 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
 267                 return TXRX_CONTINUE;
 268         }
 269
 270         if (tkip_encrypt_skb(tx, skb, test) < 0)
 271                 return TXRX_DROP;
 272
 273         if (tx->u.tx.extra_frag) {
 274                 int i;
 275                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 276                         if (tkip_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
 277                             < 0)
 278                                 return TXRX_DROP;
 279                 }
 280         }
 281
 282         return TXRX_CONTINUE;
 283 }
 284
 285
 286 ieee80211_txrx_result
 287 ieee80211_crypto_tkip_decrypt(struct ieee80211_txrx_data *rx)
 288 {
 289         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 290         u16 fc;
 291         int hdrlen, res, hwaccel = 0, wpa_test = 0;
 292         struct ieee80211_key *key = rx->key;
 293         struct sk_buff *skb = rx->skb;
 294         DECLARE_MAC_BUF(mac);
 295
 296         fc = le16_to_cpu(hdr->frame_control);
 297         hdrlen = ieee80211_get_hdrlen(fc);
 298
 299         if ((rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
 300                 return TXRX_CONTINUE;
 301
 302         if (!rx->sta || skb->len - hdrlen < 12)
 303                 return TXRX_DROP;
 304
 305         if (rx->u.rx.status->flag & RX_FLAG_DECRYPTED) {
 306                 if (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED) {
 307                         /*
 308                          * Hardware took care of all processing, including
 309                          * replay protection, and stripped the ICV/IV so
 310                          * we cannot do any checks here.
 311                          */
 312                         return TXRX_CONTINUE;
 313                 }
 314
 315                 /* let TKIP code verify IV, but skip decryption */
 316                 hwaccel = 1;
 317         }
 318
 319         res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
 320                                           key, skb->data + hdrlen,
 321                                           skb->len - hdrlen, rx->sta->addr,
 322                                           hwaccel, rx->u.rx.queue,
 323                                           &rx->u.rx.tkip_iv32,
 324                                           &rx->u.rx.tkip_iv16);
 325         if (res != TKIP_DECRYPT_OK || wpa_test) {
 326 #ifdef CONFIG_MAC80211_DEBUG
 327                 if (net_ratelimit())
 328                         printk(KERN_DEBUG "%s: TKIP decrypt failed for RX "
 329                                "frame from %s (res=%d)\n", rx->dev->name,
 330                                print_mac(mac, rx->sta->addr), res);
 331 #endif /* CONFIG_MAC80211_DEBUG */
 332                 return TXRX_DROP;
 333         }
 334
 335         /* Trim ICV */
 336         skb_trim(skb, skb->len - TKIP_ICV_LEN);
 337
 338         /* Remove IV */
 339         memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
 340         skb_pull(skb, TKIP_IV_LEN);
 341
 342         return TXRX_CONTINUE;
 343 }
 344
 345
 346 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
 347                                 int encrypted)
 348 {
 349         u16 fc;
 350         int a4_included, qos_included;
 351         u8 qos_tid, *fc_pos, *data, *sa, *da;
 352         int len_a;
 353         size_t data_len;
 354         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 355
 356         fc_pos = (u8 *) &hdr->frame_control;
 357         fc = fc_pos[0] ^ (fc_pos[1] << 8);
 358         a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 359                 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
 360
 361         ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len);
 362         data_len -= CCMP_HDR_LEN + (encrypted ? CCMP_MIC_LEN : 0);
 363         if (qos_tid & 0x80) {
 364                 qos_included = 1;
 365                 qos_tid &= 0x0f;
 366         } else
 367                 qos_included = 0;
 368         /* First block, b_0 */
 369
 370         b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
 371         /* Nonce: QoS Priority | A2 | PN */
 372         b_0[1] = qos_tid;
 373         memcpy(&b_0[2], hdr->addr2, 6);
 374         memcpy(&b_0[8], pn, CCMP_PN_LEN);
 375         /* l(m) */
 376         b_0[14] = (data_len >> 8) & 0xff;
 377         b_0[15] = data_len & 0xff;
 378
 379
 380         /* AAD (extra authenticate-only data) / masked 802.11 header
 381          * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
 382
 383         len_a = a4_included ? 28 : 22;
 384         if (qos_included)
 385                 len_a += 2;
 386
 387         aad[0] = 0; /* (len_a >> 8) & 0xff; */
 388         aad[1] = len_a & 0xff;
 389         /* Mask FC: zero subtype b4 b5 b6 */
 390         aad[2] = fc_pos[0] & ~(BIT(4) | BIT(5) | BIT(6));
 391         /* Retry, PwrMgt, MoreData; set Protected */
 392         aad[3] = (fc_pos[1] & ~(BIT(3) | BIT(4) | BIT(5))) | BIT(6);
 393         memcpy(&aad[4], &hdr->addr1, 18);
 394
 395         /* Mask Seq#, leave Frag# */
 396         aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
 397         aad[23] = 0;
 398         if (a4_included) {
 399                 memcpy(&aad[24], hdr->addr4, 6);
 400                 aad[30] = 0;
 401                 aad[31] = 0;
 402         } else
 403                 memset(&aad[24], 0, 8);
 404         if (qos_included) {
 405                 u8 *dpos = &aad[a4_included ? 30 : 24];
 406
 407                 /* Mask QoS Control field */
 408                 dpos[0] = qos_tid;
 409                 dpos[1] = 0;
 410         }
 411 }
 412
 413
 414 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
 415 {
 416         hdr[0] = pn[5];
 417         hdr[1] = pn[4];
 418         hdr[2] = 0;
 419         hdr[3] = 0x20 | (key_id << 6);
 420         hdr[4] = pn[3];
 421         hdr[5] = pn[2];
 422         hdr[6] = pn[1];
 423         hdr[7] = pn[0];
 424 }
 425
 426
 427 static inline int ccmp_hdr2pn(u8 *pn, u8 *hdr)
 428 {
 429         pn[0] = hdr[7];
 430         pn[1] = hdr[6];
 431         pn[2] = hdr[5];
 432         pn[3] = hdr[4];
 433         pn[4] = hdr[1];
 434         pn[5] = hdr[0];
 435         return (hdr[3] >> 6) & 0x03;
 436 }
 437
 438
 439 static int ccmp_encrypt_skb(struct ieee80211_txrx_data *tx,
 440                             struct sk_buff *skb, int test)
 441 {
 442         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 443         struct ieee80211_key *key = tx->key;
 444         int hdrlen, len, tailneed;
 445         u16 fc;
 446         u8 *pos, *pn, *b_0, *aad, *scratch;
 447         int i;
 448
 449         scratch = key->u.ccmp.tx_crypto_buf;
 450         b_0 = scratch + 3 * AES_BLOCK_LEN;
 451         aad = scratch + 4 * AES_BLOCK_LEN;
 452
 453         fc = le16_to_cpu(hdr->frame_control);
 454         hdrlen = ieee80211_get_hdrlen(fc);
 455         len = skb->len - hdrlen;
 456
 457         if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
 458                 tailneed = 0;
 459         else
 460                 tailneed = CCMP_MIC_LEN;
 461
 462         if ((skb_headroom(skb) < CCMP_HDR_LEN ||
 463              skb_tailroom(skb) < tailneed)) {
 464                 I802_DEBUG_INC(tx->local->tx_expand_skb_head);
 465                 if (unlikely(pskb_expand_head(skb, CCMP_HDR_LEN, tailneed,
 466                                               GFP_ATOMIC)))
 467                         return -1;
 468         }
 469
 470         pos = skb_push(skb, CCMP_HDR_LEN);
 471         memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
 472         hdr = (struct ieee80211_hdr *) pos;
 473         pos += hdrlen;
 474
 475         /* PN = PN + 1 */
 476         pn = key->u.ccmp.tx_pn;
 477
 478         for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
 479                 pn[i]++;
 480                 if (pn[i])
 481                         break;
 482         }
 483
 484         ccmp_pn2hdr(pos, pn, key->conf.keyidx);
 485
 486         if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
 487                 /* hwaccel - with preallocated room for CCMP header */
 488                 tx->u.tx.control->key_idx = key->conf.hw_key_idx;
 489                 return 0;
 490         }
 491
 492         pos += CCMP_HDR_LEN;
 493         ccmp_special_blocks(skb, pn, b_0, aad, 0);
 494         ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, b_0, aad, pos, len,
 495                                   pos, skb_put(skb, CCMP_MIC_LEN));
 496
 497         return 0;
 498 }
 499
 500
 501 ieee80211_txrx_result
 502 ieee80211_crypto_ccmp_encrypt(struct ieee80211_txrx_data *tx)
 503 {
 504         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 505         u16 fc;
 506         struct sk_buff *skb = tx->skb;
 507         int test = 0;
 508
 509         fc = le16_to_cpu(hdr->frame_control);
 510
 511         if (!WLAN_FC_DATA_PRESENT(fc))
 512                 return TXRX_CONTINUE;
 513
 514         tx->u.tx.control->icv_len = CCMP_MIC_LEN;
 515         tx->u.tx.control->iv_len = CCMP_HDR_LEN;
 516         ieee80211_tx_set_iswep(tx);
 517
 518         if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 519             !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
 520                 /* hwaccel - with no need for preallocated room for CCMP "
 521                  * header or MIC fields */
 522                 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
 523                 return TXRX_CONTINUE;
 524         }
 525
 526         if (ccmp_encrypt_skb(tx, skb, test) < 0)
 527                 return TXRX_DROP;
 528
 529         if (tx->u.tx.extra_frag) {
 530                 int i;
 531                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 532                         if (ccmp_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
 533                             < 0)
 534                                 return TXRX_DROP;
 535                 }
 536         }
 537
 538         return TXRX_CONTINUE;
 539 }
 540
 541
 542 ieee80211_txrx_result
 543 ieee80211_crypto_ccmp_decrypt(struct ieee80211_txrx_data *rx)
 544 {
 545         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 546         u16 fc;
 547         int hdrlen;
 548         struct ieee80211_key *key = rx->key;
 549         struct sk_buff *skb = rx->skb;
 550         u8 pn[CCMP_PN_LEN];
 551         int data_len;
 552         DECLARE_MAC_BUF(mac);
 553
 554         fc = le16_to_cpu(hdr->frame_control);
 555         hdrlen = ieee80211_get_hdrlen(fc);
 556
 557         if ((rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
 558                 return TXRX_CONTINUE;
 559
 560         data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
 561         if (!rx->sta || data_len < 0)
 562                 return TXRX_DROP;
 563
 564         if ((rx->u.rx.status->flag & RX_FLAG_DECRYPTED) &&
 565             (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED))
 566                 return TXRX_CONTINUE;
 567
 568         (void) ccmp_hdr2pn(pn, skb->data + hdrlen);
 569
 570         if (memcmp(pn, key->u.ccmp.rx_pn[rx->u.rx.queue], CCMP_PN_LEN) <= 0) {
 571 #ifdef CONFIG_MAC80211_DEBUG
 572                 u8 *ppn = key->u.ccmp.rx_pn[rx->u.rx.queue];
 573
 574                 printk(KERN_DEBUG "%s: CCMP replay detected for RX frame from "
 575                        "%s (RX PN %02x%02x%02x%02x%02x%02x <= prev. PN "
 576                        "%02x%02x%02x%02x%02x%02x)\n", rx->dev->name,
 577                        print_mac(mac, rx->sta->addr),
 578                        pn[0], pn[1], pn[2], pn[3], pn[4], pn[5],
 579                        ppn[0], ppn[1], ppn[2], ppn[3], ppn[4], ppn[5]);
 580 #endif /* CONFIG_MAC80211_DEBUG */
 581                 key->u.ccmp.replays++;
 582                 return TXRX_DROP;
 583         }
 584
 585         if (!(rx->u.rx.status->flag & RX_FLAG_DECRYPTED)) {
 586                 /* hardware didn't decrypt/verify MIC */
 587                 u8 *scratch, *b_0, *aad;
 588
 589                 scratch = key->u.ccmp.rx_crypto_buf;
 590                 b_0 = scratch + 3 * AES_BLOCK_LEN;
 591                 aad = scratch + 4 * AES_BLOCK_LEN;
 592
 593                 ccmp_special_blocks(skb, pn, b_0, aad, 1);
 594
 595                 if (ieee80211_aes_ccm_decrypt(
 596                             key->u.ccmp.tfm, scratch, b_0, aad,
 597                             skb->data + hdrlen + CCMP_HDR_LEN, data_len,
 598                             skb->data + skb->len - CCMP_MIC_LEN,
 599                             skb->data + hdrlen + CCMP_HDR_LEN)) {
 600 #ifdef CONFIG_MAC80211_DEBUG
 601                         if (net_ratelimit())
 602                                 printk(KERN_DEBUG "%s: CCMP decrypt failed "
 603                                        "for RX frame from %s\n", rx->dev->name,
 604                                        print_mac(mac, rx->sta->addr));
 605 #endif /* CONFIG_MAC80211_DEBUG */
 606                         return TXRX_DROP;
 607                 }
 608         }
 609
 610         memcpy(key->u.ccmp.rx_pn[rx->u.rx.queue], pn, CCMP_PN_LEN);
 611
 612         /* Remove CCMP header and MIC */
 613         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 614         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
 615         skb_pull(skb, CCMP_HDR_LEN);
 616
 617         return TXRX_CONTINUE;
 618 }