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_no_key;
 108
 109                 if (!(status->flag & RX_FLAG_IV_STRIPPED) && rx->key &&
 110                     rx->key->conf.cipher == WLAN_CIPHER_SUITE_TKIP)
 111                         goto update_iv;
 112
 113                 return RX_CONTINUE;
 114         }
 115
 116         /*
 117          * Some hardware seems to generate Michael MIC failure reports; even
 118          * though, the frame was not encrypted with TKIP and therefore has no
 119          * MIC. Ignore the flag them to avoid triggering countermeasures.
 120          */
 121         if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
 122             !(status->flag & RX_FLAG_DECRYPTED))
 123                 return RX_CONTINUE;
 124
 125         if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) {
 126                 /*
 127                  * APs with pairwise keys should never receive Michael MIC
 128                  * errors for non-zero keyidx because these are reserved for
 129                  * group keys and only the AP is sending real multicast
 130                  * frames in the BSS. (
 131                  */
 132                 return RX_DROP_UNUSABLE;
 133         }
 134
 135         if (status->flag & RX_FLAG_MMIC_ERROR)
 136                 goto mic_fail;
 137
 138         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 139         if (skb->len < hdrlen + MICHAEL_MIC_LEN)
 140                 return RX_DROP_UNUSABLE;
 141
 142         if (skb_linearize(rx->skb))
 143                 return RX_DROP_UNUSABLE;
 144         hdr = (void *)skb->data;
 145
 146         data = skb->data + hdrlen;
 147         data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
 148         key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
 149         michael_mic(key, hdr, data, data_len, mic);
 150         if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
 151                 goto mic_fail;
 152
 153         /* remove Michael MIC from payload */
 154         skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
 155
 156 update_iv:
 157         /* update IV in key information to be able to detect replays */
 158         rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32;
 159         rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16;
 160
 161         return RX_CONTINUE;
 162
 163 mic_fail:
 164         rx->key->u.tkip.mic_failures++;
 165
 166 mic_fail_no_key:
 167         /*
 168          * In some cases the key can be unset - e.g. a multicast packet, in
 169          * a driver that supports HW encryption. Send up the key idx only if
 170          * the key is set.
 171          */
 172         mac80211_ev_michael_mic_failure(rx->sdata,
 173                                         rx->key ? rx->key->conf.keyidx : -1,
 174                                         (void *) skb->data, NULL, GFP_ATOMIC);
 175         return RX_DROP_UNUSABLE;
 176 }
 177
 178
 179 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 180 {
 181         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 182         struct ieee80211_key *key = tx->key;
 183         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 184         unsigned int hdrlen;
 185         int len, tail;
 186         u8 *pos;
 187
 188         if (info->control.hw_key &&
 189             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 190             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 191                 /* hwaccel - with no need for software-generated IV */
 192                 return 0;
 193         }
 194
 195         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 196         len = skb->len - hdrlen;
 197
 198         if (info->control.hw_key)
 199                 tail = 0;
 200         else
 201                 tail = TKIP_ICV_LEN;
 202
 203         if (WARN_ON(skb_tailroom(skb) < tail ||
 204                     skb_headroom(skb) < TKIP_IV_LEN))
 205                 return -1;
 206
 207         pos = skb_push(skb, TKIP_IV_LEN);
 208         memmove(pos, pos + TKIP_IV_LEN, hdrlen);
 209         skb_set_network_header(skb, skb_network_offset(skb) + TKIP_IV_LEN);
 210         pos += hdrlen;
 211
 212         /* the HW only needs room for the IV, but not the actual IV */
 213         if (info->control.hw_key &&
 214             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 215                 return 0;
 216
 217         /* Increase IV for the frame */
 218         spin_lock(&key->u.tkip.txlock);
 219         key->u.tkip.tx.iv16++;
 220         if (key->u.tkip.tx.iv16 == 0)
 221                 key->u.tkip.tx.iv32++;
 222         pos = ieee80211_tkip_add_iv(pos, key);
 223         spin_unlock(&key->u.tkip.txlock);
 224
 225         /* hwaccel - with software IV */
 226         if (info->control.hw_key)
 227                 return 0;
 228
 229         /* Add room for ICV */
 230         skb_put(skb, TKIP_ICV_LEN);
 231
 232         return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
 233                                            key, skb, pos, len);
 234 }
 235
 236
 237 ieee80211_tx_result
 238 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
 239 {
 240         struct sk_buff *skb;
 241
 242         ieee80211_tx_set_protected(tx);
 243
 244         skb_queue_walk(&tx->skbs, skb) {
 245                 if (tkip_encrypt_skb(tx, skb) < 0)
 246                         return TX_DROP;
 247         }
 248
 249         return TX_CONTINUE;
 250 }
 251
 252
 253 ieee80211_rx_result
 254 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
 255 {
 256         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 257         int hdrlen, res, hwaccel = 0;
 258         struct ieee80211_key *key = rx->key;
 259         struct sk_buff *skb = rx->skb;
 260         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 261
 262         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 263
 264         if (!ieee80211_is_data(hdr->frame_control))
 265                 return RX_CONTINUE;
 266
 267         if (!rx->sta || skb->len - hdrlen < 12)
 268                 return RX_DROP_UNUSABLE;
 269
 270         /* it may be possible to optimize this a bit more */
 271         if (skb_linearize(rx->skb))
 272                 return RX_DROP_UNUSABLE;
 273         hdr = (void *)skb->data;
 274
 275         /*
 276          * Let TKIP code verify IV, but skip decryption.
 277          * In the case where hardware checks the IV as well,
 278          * we don't even get here, see ieee80211_rx_h_decrypt()
 279          */
 280         if (status->flag & RX_FLAG_DECRYPTED)
 281                 hwaccel = 1;
 282
 283         res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
 284                                           key, skb->data + hdrlen,
 285                                           skb->len - hdrlen, rx->sta->sta.addr,
 286                                           hdr->addr1, hwaccel, rx->security_idx,
 287                                           &rx->tkip_iv32,
 288                                           &rx->tkip_iv16);
 289         if (res != TKIP_DECRYPT_OK)
 290                 return RX_DROP_UNUSABLE;
 291
 292         /* Trim ICV */
 293         skb_trim(skb, skb->len - TKIP_ICV_LEN);
 294
 295         /* Remove IV */
 296         memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
 297         skb_pull(skb, TKIP_IV_LEN);
 298
 299         return RX_CONTINUE;
 300 }
 301
 302
 303 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
 304                                 int encrypted)
 305 {
 306         __le16 mask_fc;
 307         int a4_included, mgmt;
 308         u8 qos_tid;
 309         u8 *b_0, *aad;
 310         u16 data_len, len_a;
 311         unsigned int hdrlen;
 312         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 313
 314         memset(scratch, 0, 6 * AES_BLOCK_SIZE);
 315
 316         b_0 = scratch + 3 * AES_BLOCK_SIZE;
 317         aad = scratch + 4 * AES_BLOCK_SIZE;
 318
 319         /*
 320          * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
 321          * Retry, PwrMgt, MoreData; set Protected
 322          */
 323         mgmt = ieee80211_is_mgmt(hdr->frame_control);
 324         mask_fc = hdr->frame_control;
 325         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
 326                                 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
 327         if (!mgmt)
 328                 mask_fc &= ~cpu_to_le16(0x0070);
 329         mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 330
 331         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 332         len_a = hdrlen - 2;
 333         a4_included = ieee80211_has_a4(hdr->frame_control);
 334
 335         if (ieee80211_is_data_qos(hdr->frame_control))
 336                 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 337         else
 338                 qos_tid = 0;
 339
 340         data_len = skb->len - hdrlen - CCMP_HDR_LEN;
 341         if (encrypted)
 342                 data_len -= CCMP_MIC_LEN;
 343
 344         /* First block, b_0 */
 345         b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
 346         /* Nonce: Nonce Flags | A2 | PN
 347          * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
 348          */
 349         b_0[1] = qos_tid | (mgmt << 4);
 350         memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
 351         memcpy(&b_0[8], pn, CCMP_PN_LEN);
 352         /* l(m) */
 353         put_unaligned_be16(data_len, &b_0[14]);
 354
 355         /* AAD (extra authenticate-only data) / masked 802.11 header
 356          * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
 357         put_unaligned_be16(len_a, &aad[0]);
 358         put_unaligned(mask_fc, (__le16 *)&aad[2]);
 359         memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
 360
 361         /* Mask Seq#, leave Frag# */
 362         aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
 363         aad[23] = 0;
 364
 365         if (a4_included) {
 366                 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
 367                 aad[30] = qos_tid;
 368                 aad[31] = 0;
 369         } else {
 370                 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
 371                 aad[24] = qos_tid;
 372         }
 373 }
 374
 375
 376 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
 377 {
 378         hdr[0] = pn[5];
 379         hdr[1] = pn[4];
 380         hdr[2] = 0;
 381         hdr[3] = 0x20 | (key_id << 6);
 382         hdr[4] = pn[3];
 383         hdr[5] = pn[2];
 384         hdr[6] = pn[1];
 385         hdr[7] = pn[0];
 386 }
 387
 388
 389 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
 390 {
 391         pn[0] = hdr[7];
 392         pn[1] = hdr[6];
 393         pn[2] = hdr[5];
 394         pn[3] = hdr[4];
 395         pn[4] = hdr[1];
 396         pn[5] = hdr[0];
 397 }
 398
 399
 400 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 401 {
 402         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 403         struct ieee80211_key *key = tx->key;
 404         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 405         int hdrlen, len, tail;
 406         u8 *pos;
 407         u8 pn[6];
 408         u64 pn64;
 409         u8 scratch[6 * AES_BLOCK_SIZE];
 410
 411         if (info->control.hw_key &&
 412             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 413             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 414                 /*
 415                  * hwaccel has no need for preallocated room for CCMP
 416                  * header or MIC fields
 417                  */
 418                 return 0;
 419         }
 420
 421         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 422         len = skb->len - hdrlen;
 423
 424         if (info->control.hw_key)
 425                 tail = 0;
 426         else
 427                 tail = CCMP_MIC_LEN;
 428
 429         if (WARN_ON(skb_tailroom(skb) < tail ||
 430                     skb_headroom(skb) < CCMP_HDR_LEN))
 431                 return -1;
 432
 433         pos = skb_push(skb, CCMP_HDR_LEN);
 434         memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
 435         skb_set_network_header(skb, skb_network_offset(skb) + CCMP_HDR_LEN);
 436
 437         /* the HW only needs room for the IV, but not the actual IV */
 438         if (info->control.hw_key &&
 439             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 440                 return 0;
 441
 442         hdr = (struct ieee80211_hdr *) pos;
 443         pos += hdrlen;
 444
 445         pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
 446
 447         pn[5] = pn64;
 448         pn[4] = pn64 >> 8;
 449         pn[3] = pn64 >> 16;
 450         pn[2] = pn64 >> 24;
 451         pn[1] = pn64 >> 32;
 452         pn[0] = pn64 >> 40;
 453
 454         ccmp_pn2hdr(pos, pn, key->conf.keyidx);
 455
 456         /* hwaccel - with software CCMP header */
 457         if (info->control.hw_key)
 458                 return 0;
 459
 460         pos += CCMP_HDR_LEN;
 461         ccmp_special_blocks(skb, pn, scratch, 0);
 462         ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
 463                                   pos, skb_put(skb, CCMP_MIC_LEN));
 464
 465         return 0;
 466 }
 467
 468
 469 ieee80211_tx_result
 470 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
 471 {
 472         struct sk_buff *skb;
 473
 474         ieee80211_tx_set_protected(tx);
 475
 476         skb_queue_walk(&tx->skbs, skb) {
 477                 if (ccmp_encrypt_skb(tx, skb) < 0)
 478                         return TX_DROP;
 479         }
 480
 481         return TX_CONTINUE;
 482 }
 483
 484
 485 ieee80211_rx_result
 486 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
 487 {
 488         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 489         int hdrlen;
 490         struct ieee80211_key *key = rx->key;
 491         struct sk_buff *skb = rx->skb;
 492         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 493         u8 pn[CCMP_PN_LEN];
 494         int data_len;
 495         int queue;
 496
 497         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 498
 499         if (!ieee80211_is_data(hdr->frame_control) &&
 500             !ieee80211_is_robust_mgmt_frame(hdr))
 501                 return RX_CONTINUE;
 502
 503         data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
 504         if (!rx->sta || data_len < 0)
 505                 return RX_DROP_UNUSABLE;
 506
 507         if (status->flag & RX_FLAG_DECRYPTED) {
 508                 if (!pskb_may_pull(rx->skb, hdrlen + CCMP_HDR_LEN))
 509                         return RX_DROP_UNUSABLE;
 510         } else {
 511                 if (skb_linearize(rx->skb))
 512                         return RX_DROP_UNUSABLE;
 513         }
 514
 515         ccmp_hdr2pn(pn, skb->data + hdrlen);
 516
 517         queue = rx->security_idx;
 518
 519         if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
 520                 key->u.ccmp.replays++;
 521                 return RX_DROP_UNUSABLE;
 522         }
 523
 524         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 525                 u8 scratch[6 * AES_BLOCK_SIZE];
 526                 /* hardware didn't decrypt/verify MIC */
 527                 ccmp_special_blocks(skb, pn, scratch, 1);
 528
 529                 if (ieee80211_aes_ccm_decrypt(
 530                             key->u.ccmp.tfm, scratch,
 531                             skb->data + hdrlen + CCMP_HDR_LEN, data_len,
 532                             skb->data + skb->len - CCMP_MIC_LEN,
 533                             skb->data + hdrlen + CCMP_HDR_LEN))
 534                         return RX_DROP_UNUSABLE;
 535         }
 536
 537         memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
 538
 539         /* Remove CCMP header and MIC */
 540         if (pskb_trim(skb, skb->len - CCMP_MIC_LEN))
 541                 return RX_DROP_UNUSABLE;
 542         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
 543         skb_pull(skb, CCMP_HDR_LEN);
 544
 545         return RX_CONTINUE;
 546 }
 547
 548
 549 static void bip_aad(struct sk_buff *skb, u8 *aad)
 550 {
 551         __le16 mask_fc;
 552         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 553
 554         /* BIP AAD: FC(masked) || A1 || A2 || A3 */
 555
 556         /* FC type/subtype */
 557         /* Mask FC Retry, PwrMgt, MoreData flags to zero */
 558         mask_fc = hdr->frame_control;
 559         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM |
 560                                 IEEE80211_FCTL_MOREDATA);
 561         put_unaligned(mask_fc, (__le16 *) &aad[0]);
 562         /* A1 || A2 || A3 */
 563         memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN);
 564 }
 565
 566
 567 static inline void bip_ipn_set64(u8 *d, u64 pn)
 568 {
 569         *d++ = pn;
 570         *d++ = pn >> 8;
 571         *d++ = pn >> 16;
 572         *d++ = pn >> 24;
 573         *d++ = pn >> 32;
 574         *d = pn >> 40;
 575 }
 576
 577 static inline void bip_ipn_swap(u8 *d, const u8 *s)
 578 {
 579         *d++ = s[5];
 580         *d++ = s[4];
 581         *d++ = s[3];
 582         *d++ = s[2];
 583         *d++ = s[1];
 584         *d = s[0];
 585 }
 586
 587
 588 ieee80211_tx_result
 589 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 590 {
 591         struct sk_buff *skb;
 592         struct ieee80211_tx_info *info;
 593         struct ieee80211_key *key = tx->key;
 594         struct ieee80211_mmie *mmie;
 595         u8 aad[20];
 596         u64 pn64;
 597
 598         if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
 599                 return TX_DROP;
 600
 601         skb = skb_peek(&tx->skbs);
 602
 603         info = IEEE80211_SKB_CB(skb);
 604
 605         if (info->control.hw_key)
 606                 return TX_CONTINUE;
 607
 608         if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 609                 return TX_DROP;
 610
 611         mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
 612         mmie->element_id = WLAN_EID_MMIE;
 613         mmie->length = sizeof(*mmie) - 2;
 614         mmie->key_id = cpu_to_le16(key->conf.keyidx);
 615
 616         /* PN = PN + 1 */
 617         pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
 618
 619         bip_ipn_set64(mmie->sequence_number, pn64);
 620
 621         bip_aad(skb, aad);
 622
 623         /*
 624          * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
 625          */
 626         ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 627                            skb->data + 24, skb->len - 24, mmie->mic);
 628
 629         return TX_CONTINUE;
 630 }
 631
 632
 633 ieee80211_rx_result
 634 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 635 {
 636         struct sk_buff *skb = rx->skb;
 637         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 638         struct ieee80211_key *key = rx->key;
 639         struct ieee80211_mmie *mmie;
 640         u8 aad[20], mic[8], ipn[6];
 641         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 642
 643         if (!ieee80211_is_mgmt(hdr->frame_control))
 644                 return RX_CONTINUE;
 645
 646         /* management frames are already linear */
 647
 648         if (skb->len < 24 + sizeof(*mmie))
 649                 return RX_DROP_UNUSABLE;
 650
 651         mmie = (struct ieee80211_mmie *)
 652                 (skb->data + skb->len - sizeof(*mmie));
 653         if (mmie->element_id != WLAN_EID_MMIE ||
 654             mmie->length != sizeof(*mmie) - 2)
 655                 return RX_DROP_UNUSABLE; /* Invalid MMIE */
 656
 657         bip_ipn_swap(ipn, mmie->sequence_number);
 658
 659         if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
 660                 key->u.aes_cmac.replays++;
 661                 return RX_DROP_UNUSABLE;
 662         }
 663
 664         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 665                 /* hardware didn't decrypt/verify MIC */
 666                 bip_aad(skb, aad);
 667                 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 668                                    skb->data + 24, skb->len - 24, mic);
 669                 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
 670                         key->u.aes_cmac.icverrors++;
 671                         return RX_DROP_UNUSABLE;
 672                 }
 673         }
 674
 675         memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
 676
 677         /* Remove MMIE */
 678         skb_trim(skb, skb->len - sizeof(*mmie));
 679
 680         return RX_CONTINUE;
 681 }
 682
 683 ieee80211_tx_result
 684 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
 685 {
 686         struct sk_buff *skb;
 687         struct ieee80211_tx_info *info = NULL;
 688
 689         skb_queue_walk(&tx->skbs, skb) {
 690                 info  = IEEE80211_SKB_CB(skb);
 691
 692                 /* handle hw-only algorithm */
 693                 if (!info->control.hw_key)
 694                         return TX_DROP;
 695         }
 696
 697         ieee80211_tx_set_protected(tx);
 698
 699         return TX_CONTINUE;
 700 }