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