net/mac80211/wpa.c

   1 /*
   2  * Copyright 2002-2004, Instant802 Networks, Inc.
   3  * Copyright 2008, Jouni Malinen <j@w1.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/netdevice.h>
  11 #include <linux/types.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/compiler.h>
  14 #include <linux/ieee80211.h>
  15 #include <linux/gfp.h>
  16 #include <asm/unaligned.h>
  17 #include <net/mac80211.h>
  18 #include <crypto/aes.h>
  19
  20 #include "ieee80211_i.h"
  21 #include "michael.h"
  22 #include "tkip.h"
  23 #include "aes_ccm.h"
  24 #include "aes_cmac.h"
  25 #include "wpa.h"
  26
  27 ieee80211_tx_result
  28 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
  29 {
  30         u8 *data, *key, *mic;
  31         size_t data_len;
  32         unsigned int hdrlen;
  33         struct ieee80211_hdr *hdr;
  34         struct sk_buff *skb = tx->skb;
  35         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  36         int tail;
  37
  38         hdr = (struct ieee80211_hdr *)skb->data;
  39         if (!tx->key || tx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
  40             skb->len < 24 || !ieee80211_is_data_present(hdr->frame_control))
  41                 return TX_CONTINUE;
  42
  43         hdrlen = ieee80211_hdrlen(hdr->frame_control);
  44         if (skb->len < hdrlen)
  45                 return TX_DROP;
  46
  47         data = skb->data + hdrlen;
  48         data_len = skb->len - hdrlen;
  49
  50         if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) {
  51                 /* Need to use software crypto for the test */
  52                 info->control.hw_key = NULL;
  53         }
  54
  55         if (info->control.hw_key &&
  56             (info->flags & IEEE80211_TX_CTL_DONTFRAG ||
  57              tx->local->ops->set_frag_threshold) &&
  58             !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
  59                 /* hwaccel - with no need for SW-generated MMIC */
  60                 return TX_CONTINUE;
  61         }
  62
  63         tail = MICHAEL_MIC_LEN;
  64         if (!info->control.hw_key)
  65                 tail += TKIP_ICV_LEN;
  66
  67         if (WARN_ON(skb_tailroom(skb) < tail ||
  68                     skb_headroom(skb) < TKIP_IV_LEN))
  69                 return TX_DROP;
  70
  71         key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY];
  72         mic = skb_put(skb, MICHAEL_MIC_LEN);
  73         michael_mic(key, hdr, data, data_len, mic);
  74         if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE))
  75                 mic[0]++;
  76
  77         return TX_CONTINUE;
  78 }
  79
  80
  81 ieee80211_rx_result
  82 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
  83 {
  84         u8 *data, *key = NULL;
  85         size_t data_len;
  86         unsigned int hdrlen;
  87         u8 mic[MICHAEL_MIC_LEN];
  88         struct sk_buff *skb = rx->skb;
  89         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
  90         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
  91
  92         /*
  93          * it makes no sense to check for MIC errors on anything other
  94          * than data frames.
  95          */
  96         if (!ieee80211_is_data_present(hdr->frame_control))
  97                 return RX_CONTINUE;
  98
  99         /*
 100          * No way to verify the MIC if the hardware stripped it or
 101          * the IV with the key index. In this case we have solely rely
 102          * on the driver to set RX_FLAG_MMIC_ERROR in the event of a
 103          * MIC failure report.
 104          */
 105         if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) {
 106                 if (status->flag & RX_FLAG_MMIC_ERROR)
 107                         goto mic_fail;
 108
 109                 if (!(status->flag & RX_FLAG_IV_STRIPPED) && rx->key)
 110                         goto update_iv;
 111
 112                 return RX_CONTINUE;
 113         }
 114
 115         /*
 116          * Some hardware seems to generate Michael MIC failure reports; even
 117          * though, the frame was not encrypted with TKIP and therefore has no
 118          * MIC. Ignore the flag them to avoid triggering countermeasures.
 119          */
 120         if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
 121             !(status->flag & RX_FLAG_DECRYPTED))
 122                 return RX_CONTINUE;
 123
 124         if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) {
 125                 /*
 126                  * APs with pairwise keys should never receive Michael MIC
 127                  * errors for non-zero keyidx because these are reserved for
 128                  * group keys and only the AP is sending real multicast
 129                  * frames in the BSS. (
 130                  */
 131                 return RX_DROP_UNUSABLE;
 132         }
 133
 134         if (status->flag & RX_FLAG_MMIC_ERROR)
 135                 goto mic_fail;
 136
 137         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 138         if (skb->len < hdrlen + MICHAEL_MIC_LEN)
 139                 return RX_DROP_UNUSABLE;
 140
 141         if (skb_linearize(rx->skb))
 142                 return RX_DROP_UNUSABLE;
 143         hdr = (void *)skb->data;
 144
 145         data = skb->data + hdrlen;
 146         data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
 147         key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
 148         michael_mic(key, hdr, data, data_len, mic);
 149         if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
 150                 goto mic_fail;
 151
 152         /* remove Michael MIC from payload */
 153         skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
 154
 155 update_iv:
 156         /* update IV in key information to be able to detect replays */
 157         rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32;
 158         rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16;
 159
 160         return RX_CONTINUE;
 161
 162 mic_fail:
 163         /*
 164          * In some cases the key can be unset - e.g. a multicast packet, in
 165          * a driver that supports HW encryption. Send up the key idx only if
 166          * the key is set.
 167          */
 168         mac80211_ev_michael_mic_failure(rx->sdata,
 169                                         rx->key ? rx->key->conf.keyidx : -1,
 170                                         (void *) skb->data, NULL, GFP_ATOMIC);
 171         return RX_DROP_UNUSABLE;
 172 }
 173
 174
 175 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 176 {
 177         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 178         struct ieee80211_key *key = tx->key;
 179         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 180         unsigned long flags;
 181         unsigned int hdrlen;
 182         int len, tail;
 183         u8 *pos;
 184
 185         if (info->control.hw_key &&
 186             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
 187                 /* hwaccel - with no need for software-generated IV */
 188                 return 0;
 189         }
 190
 191         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 192         len = skb->len - hdrlen;
 193
 194         if (info->control.hw_key)
 195                 tail = 0;
 196         else
 197                 tail = TKIP_ICV_LEN;
 198
 199         if (WARN_ON(skb_tailroom(skb) < tail ||
 200                     skb_headroom(skb) < TKIP_IV_LEN))
 201                 return -1;
 202
 203         pos = skb_push(skb, TKIP_IV_LEN);
 204         memmove(pos, pos + TKIP_IV_LEN, hdrlen);
 205         pos += hdrlen;
 206
 207         /* Increase IV for the frame */
 208         spin_lock_irqsave(&key->u.tkip.txlock, flags);
 209         key->u.tkip.tx.iv16++;
 210         if (key->u.tkip.tx.iv16 == 0)
 211                 key->u.tkip.tx.iv32++;
 212         pos = ieee80211_tkip_add_iv(pos, key);
 213         spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
 214
 215         /* hwaccel - with software IV */
 216         if (info->control.hw_key)
 217                 return 0;
 218
 219         /* Add room for ICV */
 220         skb_put(skb, TKIP_ICV_LEN);
 221
 222         return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
 223                                            key, skb, pos, len);
 224 }
 225
 226
 227 ieee80211_tx_result
 228 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
 229 {
 230         struct sk_buff *skb;
 231
 232         ieee80211_tx_set_protected(tx);
 233
 234         skb_queue_walk(&tx->skbs, skb) {
 235                 if (tkip_encrypt_skb(tx, skb) < 0)
 236                         return TX_DROP;
 237         }
 238
 239         return TX_CONTINUE;
 240 }
 241
 242
 243 ieee80211_rx_result
 244 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
 245 {
 246         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 247         int hdrlen, res, hwaccel = 0;
 248         struct ieee80211_key *key = rx->key;
 249         struct sk_buff *skb = rx->skb;
 250         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 251
 252         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 253
 254         if (!ieee80211_is_data(hdr->frame_control))
 255                 return RX_CONTINUE;
 256
 257         if (!rx->sta || skb->len - hdrlen < 12)
 258                 return RX_DROP_UNUSABLE;
 259
 260         /* it may be possible to optimize this a bit more */
 261         if (skb_linearize(rx->skb))
 262                 return RX_DROP_UNUSABLE;
 263         hdr = (void *)skb->data;
 264
 265         /*
 266          * Let TKIP code verify IV, but skip decryption.
 267          * In the case where hardware checks the IV as well,
 268          * we don't even get here, see ieee80211_rx_h_decrypt()
 269          */
 270         if (status->flag & RX_FLAG_DECRYPTED)
 271                 hwaccel = 1;
 272
 273         res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
 274                                           key, skb->data + hdrlen,
 275                                           skb->len - hdrlen, rx->sta->sta.addr,
 276                                           hdr->addr1, hwaccel, rx->security_idx,
 277                                           &rx->tkip_iv32,
 278                                           &rx->tkip_iv16);
 279         if (res != TKIP_DECRYPT_OK)
 280                 return RX_DROP_UNUSABLE;
 281
 282         /* Trim ICV */
 283         skb_trim(skb, skb->len - TKIP_ICV_LEN);
 284
 285         /* Remove IV */
 286         memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
 287         skb_pull(skb, TKIP_IV_LEN);
 288
 289         return RX_CONTINUE;
 290 }
 291
 292
 293 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
 294                                 int encrypted)
 295 {
 296         __le16 mask_fc;
 297         int a4_included, mgmt;
 298         u8 qos_tid;
 299         u8 *b_0, *aad;
 300         u16 data_len, len_a;
 301         unsigned int hdrlen;
 302         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 303
 304         memset(scratch, 0, 6 * AES_BLOCK_SIZE);
 305
 306         b_0 = scratch + 3 * AES_BLOCK_SIZE;
 307         aad = scratch + 4 * AES_BLOCK_SIZE;
 308
 309         /*
 310          * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
 311          * Retry, PwrMgt, MoreData; set Protected
 312          */
 313         mgmt = ieee80211_is_mgmt(hdr->frame_control);
 314         mask_fc = hdr->frame_control;
 315         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
 316                                 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
 317         if (!mgmt)
 318                 mask_fc &= ~cpu_to_le16(0x0070);
 319         mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 320
 321         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 322         len_a = hdrlen - 2;
 323         a4_included = ieee80211_has_a4(hdr->frame_control);
 324
 325         if (ieee80211_is_data_qos(hdr->frame_control))
 326                 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 327         else
 328                 qos_tid = 0;
 329
 330         data_len = skb->len - hdrlen - CCMP_HDR_LEN;
 331         if (encrypted)
 332                 data_len -= CCMP_MIC_LEN;
 333
 334         /* First block, b_0 */
 335         b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
 336         /* Nonce: Nonce Flags | A2 | PN
 337          * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
 338          */
 339         b_0[1] = qos_tid | (mgmt << 4);
 340         memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
 341         memcpy(&b_0[8], pn, CCMP_PN_LEN);
 342         /* l(m) */
 343         put_unaligned_be16(data_len, &b_0[14]);
 344
 345         /* AAD (extra authenticate-only data) / masked 802.11 header
 346          * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
 347         put_unaligned_be16(len_a, &aad[0]);
 348         put_unaligned(mask_fc, (__le16 *)&aad[2]);
 349         memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
 350
 351         /* Mask Seq#, leave Frag# */
 352         aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
 353         aad[23] = 0;
 354
 355         if (a4_included) {
 356                 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
 357                 aad[30] = qos_tid;
 358                 aad[31] = 0;
 359         } else {
 360                 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
 361                 aad[24] = qos_tid;
 362         }
 363 }
 364
 365
 366 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
 367 {
 368         hdr[0] = pn[5];
 369         hdr[1] = pn[4];
 370         hdr[2] = 0;
 371         hdr[3] = 0x20 | (key_id << 6);
 372         hdr[4] = pn[3];
 373         hdr[5] = pn[2];
 374         hdr[6] = pn[1];
 375         hdr[7] = pn[0];
 376 }
 377
 378
 379 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
 380 {
 381         pn[0] = hdr[7];
 382         pn[1] = hdr[6];
 383         pn[2] = hdr[5];
 384         pn[3] = hdr[4];
 385         pn[4] = hdr[1];
 386         pn[5] = hdr[0];
 387 }
 388
 389
 390 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 391 {
 392         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 393         struct ieee80211_key *key = tx->key;
 394         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 395         int hdrlen, len, tail;
 396         u8 *pos;
 397         u8 pn[6];
 398         u64 pn64;
 399         u8 scratch[6 * AES_BLOCK_SIZE];
 400
 401         if (info->control.hw_key &&
 402             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 403             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 404                 /*
 405                  * hwaccel has no need for preallocated room for CCMP
 406                  * header or MIC fields
 407                  */
 408                 return 0;
 409         }
 410
 411         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 412         len = skb->len - hdrlen;
 413
 414         if (info->control.hw_key)
 415                 tail = 0;
 416         else
 417                 tail = CCMP_MIC_LEN;
 418
 419         if (WARN_ON(skb_tailroom(skb) < tail ||
 420                     skb_headroom(skb) < CCMP_HDR_LEN))
 421                 return -1;
 422
 423         pos = skb_push(skb, CCMP_HDR_LEN);
 424         memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
 425
 426         /* the HW only needs room for the IV, but not the actual IV */
 427         if (info->control.hw_key &&
 428             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 429                 return 0;
 430
 431         hdr = (struct ieee80211_hdr *) pos;
 432         pos += hdrlen;
 433
 434         pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
 435
 436         pn[5] = pn64;
 437         pn[4] = pn64 >> 8;
 438         pn[3] = pn64 >> 16;
 439         pn[2] = pn64 >> 24;
 440         pn[1] = pn64 >> 32;
 441         pn[0] = pn64 >> 40;
 442
 443         ccmp_pn2hdr(pos, pn, key->conf.keyidx);
 444
 445         /* hwaccel - with software CCMP header */
 446         if (info->control.hw_key)
 447                 return 0;
 448
 449         pos += CCMP_HDR_LEN;
 450         ccmp_special_blocks(skb, pn, scratch, 0);
 451         ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
 452                                   pos, skb_put(skb, CCMP_MIC_LEN));
 453
 454         return 0;
 455 }
 456
 457
 458 ieee80211_tx_result
 459 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
 460 {
 461         struct sk_buff *skb;
 462
 463         ieee80211_tx_set_protected(tx);
 464
 465         skb_queue_walk(&tx->skbs, skb) {
 466                 if (ccmp_encrypt_skb(tx, skb) < 0)
 467                         return TX_DROP;
 468         }
 469
 470         return TX_CONTINUE;
 471 }
 472
 473
 474 ieee80211_rx_result
 475 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
 476 {
 477         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 478         int hdrlen;
 479         struct ieee80211_key *key = rx->key;
 480         struct sk_buff *skb = rx->skb;
 481         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 482         u8 pn[CCMP_PN_LEN];
 483         int data_len;
 484         int queue;
 485
 486         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 487
 488         if (!ieee80211_is_data(hdr->frame_control) &&
 489             !ieee80211_is_robust_mgmt_frame(hdr))
 490                 return RX_CONTINUE;
 491
 492         data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
 493         if (!rx->sta || data_len < 0)
 494                 return RX_DROP_UNUSABLE;
 495
 496         if (status->flag & RX_FLAG_DECRYPTED) {
 497                 if (!pskb_may_pull(rx->skb, hdrlen + CCMP_HDR_LEN))
 498                         return RX_DROP_UNUSABLE;
 499         } else {
 500                 if (skb_linearize(rx->skb))
 501                         return RX_DROP_UNUSABLE;
 502         }
 503
 504         ccmp_hdr2pn(pn, skb->data + hdrlen);
 505
 506         queue = rx->security_idx;
 507
 508         if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
 509                 key->u.ccmp.replays++;
 510                 return RX_DROP_UNUSABLE;
 511         }
 512
 513         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 514                 u8 scratch[6 * AES_BLOCK_SIZE];
 515                 /* hardware didn't decrypt/verify MIC */
 516                 ccmp_special_blocks(skb, pn, scratch, 1);
 517
 518                 if (ieee80211_aes_ccm_decrypt(
 519                             key->u.ccmp.tfm, scratch,
 520                             skb->data + hdrlen + CCMP_HDR_LEN, data_len,
 521                             skb->data + skb->len - CCMP_MIC_LEN,
 522                             skb->data + hdrlen + CCMP_HDR_LEN))
 523                         return RX_DROP_UNUSABLE;
 524         }
 525
 526         memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
 527
 528         /* Remove CCMP header and MIC */
 529         if (pskb_trim(skb, skb->len - CCMP_MIC_LEN))
 530                 return RX_DROP_UNUSABLE;
 531         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
 532         skb_pull(skb, CCMP_HDR_LEN);
 533
 534         return RX_CONTINUE;
 535 }
 536
 537
 538 static void bip_aad(struct sk_buff *skb, u8 *aad)
 539 {
 540         /* BIP AAD: FC(masked) || A1 || A2 || A3 */
 541
 542         /* FC type/subtype */
 543         aad[0] = skb->data[0];
 544         /* Mask FC Retry, PwrMgt, MoreData flags to zero */
 545         aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6));
 546         /* A1 || A2 || A3 */
 547         memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN);
 548 }
 549
 550
 551 static inline void bip_ipn_set64(u8 *d, u64 pn)
 552 {
 553         *d++ = pn;
 554         *d++ = pn >> 8;
 555         *d++ = pn >> 16;
 556         *d++ = pn >> 24;
 557         *d++ = pn >> 32;
 558         *d = pn >> 40;
 559 }
 560
 561 static inline void bip_ipn_swap(u8 *d, const u8 *s)
 562 {
 563         *d++ = s[5];
 564         *d++ = s[4];
 565         *d++ = s[3];
 566         *d++ = s[2];
 567         *d++ = s[1];
 568         *d = s[0];
 569 }
 570
 571
 572 ieee80211_tx_result
 573 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 574 {
 575         struct sk_buff *skb;
 576         struct ieee80211_tx_info *info;
 577         struct ieee80211_key *key = tx->key;
 578         struct ieee80211_mmie *mmie;
 579         u8 aad[20];
 580         u64 pn64;
 581
 582         if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
 583                 return TX_DROP;
 584
 585         skb = skb_peek(&tx->skbs);
 586
 587         info = IEEE80211_SKB_CB(skb);
 588
 589         if (info->control.hw_key)
 590                 return TX_CONTINUE;
 591
 592         if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 593                 return TX_DROP;
 594
 595         mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
 596         mmie->element_id = WLAN_EID_MMIE;
 597         mmie->length = sizeof(*mmie) - 2;
 598         mmie->key_id = cpu_to_le16(key->conf.keyidx);
 599
 600         /* PN = PN + 1 */
 601         pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
 602
 603         bip_ipn_set64(mmie->sequence_number, pn64);
 604
 605         bip_aad(skb, aad);
 606
 607         /*
 608          * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
 609          */
 610         ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 611                            skb->data + 24, skb->len - 24, mmie->mic);
 612
 613         return TX_CONTINUE;
 614 }
 615
 616
 617 ieee80211_rx_result
 618 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 619 {
 620         struct sk_buff *skb = rx->skb;
 621         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 622         struct ieee80211_key *key = rx->key;
 623         struct ieee80211_mmie *mmie;
 624         u8 aad[20], mic[8], ipn[6];
 625         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 626
 627         if (!ieee80211_is_mgmt(hdr->frame_control))
 628                 return RX_CONTINUE;
 629
 630         /* management frames are already linear */
 631
 632         if (skb->len < 24 + sizeof(*mmie))
 633                 return RX_DROP_UNUSABLE;
 634
 635         mmie = (struct ieee80211_mmie *)
 636                 (skb->data + skb->len - sizeof(*mmie));
 637         if (mmie->element_id != WLAN_EID_MMIE ||
 638             mmie->length != sizeof(*mmie) - 2)
 639                 return RX_DROP_UNUSABLE; /* Invalid MMIE */
 640
 641         bip_ipn_swap(ipn, mmie->sequence_number);
 642
 643         if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
 644                 key->u.aes_cmac.replays++;
 645                 return RX_DROP_UNUSABLE;
 646         }
 647
 648         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 649                 /* hardware didn't decrypt/verify MIC */
 650                 bip_aad(skb, aad);
 651                 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 652                                    skb->data + 24, skb->len - 24, mic);
 653                 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
 654                         key->u.aes_cmac.icverrors++;
 655                         return RX_DROP_UNUSABLE;
 656                 }
 657         }
 658
 659         memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
 660
 661         /* Remove MMIE */
 662         skb_trim(skb, skb->len - sizeof(*mmie));
 663
 664         return RX_CONTINUE;
 665 }
 666
 667 ieee80211_tx_result
 668 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
 669 {
 670         struct sk_buff *skb;
 671         struct ieee80211_tx_info *info = NULL;
 672
 673         skb_queue_walk(&tx->skbs, skb) {
 674                 info  = IEEE80211_SKB_CB(skb);
 675
 676                 /* handle hw-only algorithm */
 677                 if (!info->control.hw_key)
 678                         return TX_DROP;
 679         }
 680
 681         ieee80211_tx_set_protected(tx);
 682
 683         return TX_CONTINUE;
 684 }