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 += IEEE80211_TKIP_ICV_LEN;
  66
  67         if (WARN_ON(skb_tailroom(skb) < tail ||
  68                     skb_headroom(skb) < IEEE80211_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 = IEEE80211_TKIP_ICV_LEN;
 202
 203         if (WARN_ON(skb_tailroom(skb) < tail ||
 204                     skb_headroom(skb) < IEEE80211_TKIP_IV_LEN))
 205                 return -1;
 206
 207         pos = skb_push(skb, IEEE80211_TKIP_IV_LEN);
 208         memmove(pos, pos + IEEE80211_TKIP_IV_LEN, hdrlen);
 209         skb_set_network_header(skb, skb_network_offset(skb) +
 210                                     IEEE80211_TKIP_IV_LEN);
 211         pos += hdrlen;
 212
 213         /* the HW only needs room for the IV, but not the actual IV */
 214         if (info->control.hw_key &&
 215             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 216                 return 0;
 217
 218         /* Increase IV for the frame */
 219         spin_lock(&key->u.tkip.txlock);
 220         key->u.tkip.tx.iv16++;
 221         if (key->u.tkip.tx.iv16 == 0)
 222                 key->u.tkip.tx.iv32++;
 223         pos = ieee80211_tkip_add_iv(pos, key);
 224         spin_unlock(&key->u.tkip.txlock);
 225
 226         /* hwaccel - with software IV */
 227         if (info->control.hw_key)
 228                 return 0;
 229
 230         /* Add room for ICV */
 231         skb_put(skb, IEEE80211_TKIP_ICV_LEN);
 232
 233         return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
 234                                            key, skb, pos, len);
 235 }
 236
 237
 238 ieee80211_tx_result
 239 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
 240 {
 241         struct sk_buff *skb;
 242
 243         ieee80211_tx_set_protected(tx);
 244
 245         skb_queue_walk(&tx->skbs, skb) {
 246                 if (tkip_encrypt_skb(tx, skb) < 0)
 247                         return TX_DROP;
 248         }
 249
 250         return TX_CONTINUE;
 251 }
 252
 253
 254 ieee80211_rx_result
 255 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
 256 {
 257         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 258         int hdrlen, res, hwaccel = 0;
 259         struct ieee80211_key *key = rx->key;
 260         struct sk_buff *skb = rx->skb;
 261         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 262
 263         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 264
 265         if (!ieee80211_is_data(hdr->frame_control))
 266                 return RX_CONTINUE;
 267
 268         if (!rx->sta || skb->len - hdrlen < 12)
 269                 return RX_DROP_UNUSABLE;
 270
 271         /* it may be possible to optimize this a bit more */
 272         if (skb_linearize(rx->skb))
 273                 return RX_DROP_UNUSABLE;
 274         hdr = (void *)skb->data;
 275
 276         /*
 277          * Let TKIP code verify IV, but skip decryption.
 278          * In the case where hardware checks the IV as well,
 279          * we don't even get here, see ieee80211_rx_h_decrypt()
 280          */
 281         if (status->flag & RX_FLAG_DECRYPTED)
 282                 hwaccel = 1;
 283
 284         res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
 285                                           key, skb->data + hdrlen,
 286                                           skb->len - hdrlen, rx->sta->sta.addr,
 287                                           hdr->addr1, hwaccel, rx->security_idx,
 288                                           &rx->tkip_iv32,
 289                                           &rx->tkip_iv16);
 290         if (res != TKIP_DECRYPT_OK)
 291                 return RX_DROP_UNUSABLE;
 292
 293         /* Trim ICV */
 294         skb_trim(skb, skb->len - IEEE80211_TKIP_ICV_LEN);
 295
 296         /* Remove IV */
 297         memmove(skb->data + IEEE80211_TKIP_IV_LEN, skb->data, hdrlen);
 298         skb_pull(skb, IEEE80211_TKIP_IV_LEN);
 299
 300         return RX_CONTINUE;
 301 }
 302
 303
 304 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad)
 305 {
 306         __le16 mask_fc;
 307         int a4_included, mgmt;
 308         u8 qos_tid;
 309         u16 len_a;
 310         unsigned int hdrlen;
 311         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 312
 313         /*
 314          * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
 315          * Retry, PwrMgt, MoreData; set Protected
 316          */
 317         mgmt = ieee80211_is_mgmt(hdr->frame_control);
 318         mask_fc = hdr->frame_control;
 319         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
 320                                 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
 321         if (!mgmt)
 322                 mask_fc &= ~cpu_to_le16(0x0070);
 323         mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 324
 325         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 326         len_a = hdrlen - 2;
 327         a4_included = ieee80211_has_a4(hdr->frame_control);
 328
 329         if (ieee80211_is_data_qos(hdr->frame_control))
 330                 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 331         else
 332                 qos_tid = 0;
 333
 334         /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
 335          * mode authentication are not allowed to collide, yet both are derived
 336          * from this vector b_0. We only set L := 1 here to indicate that the
 337          * data size can be represented in (L+1) bytes. The CCM layer will take
 338          * care of storing the data length in the top (L+1) bytes and setting
 339          * and clearing the other bits as is required to derive the two IVs.
 340          */
 341         b_0[0] = 0x1;
 342
 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, IEEE80211_CCMP_PN_LEN);
 349
 350         /* AAD (extra authenticate-only data) / masked 802.11 header
 351          * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
 352         put_unaligned_be16(len_a, &aad[0]);
 353         put_unaligned(mask_fc, (__le16 *)&aad[2]);
 354         memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
 355
 356         /* Mask Seq#, leave Frag# */
 357         aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
 358         aad[23] = 0;
 359
 360         if (a4_included) {
 361                 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
 362                 aad[30] = qos_tid;
 363                 aad[31] = 0;
 364         } else {
 365                 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
 366                 aad[24] = qos_tid;
 367         }
 368 }
 369
 370
 371 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
 372 {
 373         hdr[0] = pn[5];
 374         hdr[1] = pn[4];
 375         hdr[2] = 0;
 376         hdr[3] = 0x20 | (key_id << 6);
 377         hdr[4] = pn[3];
 378         hdr[5] = pn[2];
 379         hdr[6] = pn[1];
 380         hdr[7] = pn[0];
 381 }
 382
 383
 384 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
 385 {
 386         pn[0] = hdr[7];
 387         pn[1] = hdr[6];
 388         pn[2] = hdr[5];
 389         pn[3] = hdr[4];
 390         pn[4] = hdr[1];
 391         pn[5] = hdr[0];
 392 }
 393
 394
 395 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 396 {
 397         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 398         struct ieee80211_key *key = tx->key;
 399         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 400         int hdrlen, len, tail;
 401         u8 *pos;
 402         u8 pn[6];
 403         u64 pn64;
 404         u8 aad[2 * AES_BLOCK_SIZE];
 405         u8 b_0[AES_BLOCK_SIZE];
 406
 407         if (info->control.hw_key &&
 408             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 409             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) &&
 410             !((info->control.hw_key->flags &
 411                IEEE80211_KEY_FLAG_GENERATE_IV_MGMT) &&
 412               ieee80211_is_mgmt(hdr->frame_control))) {
 413                 /*
 414                  * hwaccel has no need for preallocated room for CCMP
 415                  * header or MIC fields
 416                  */
 417                 return 0;
 418         }
 419
 420         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 421         len = skb->len - hdrlen;
 422
 423         if (info->control.hw_key)
 424                 tail = 0;
 425         else
 426                 tail = IEEE80211_CCMP_MIC_LEN;
 427
 428         if (WARN_ON(skb_tailroom(skb) < tail ||
 429                     skb_headroom(skb) < IEEE80211_CCMP_HDR_LEN))
 430                 return -1;
 431
 432         pos = skb_push(skb, IEEE80211_CCMP_HDR_LEN);
 433         memmove(pos, pos + IEEE80211_CCMP_HDR_LEN, hdrlen);
 434         skb_set_network_header(skb, skb_network_offset(skb) +
 435                                     IEEE80211_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 += IEEE80211_CCMP_HDR_LEN;
 461         ccmp_special_blocks(skb, pn, b_0, aad);
 462         ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len,
 463                                   skb_put(skb, IEEE80211_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[IEEE80211_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(skb))
 501                 return RX_CONTINUE;
 502
 503         data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN -
 504                    IEEE80211_CCMP_MIC_LEN;
 505         if (!rx->sta || data_len < 0)
 506                 return RX_DROP_UNUSABLE;
 507
 508         if (status->flag & RX_FLAG_DECRYPTED) {
 509                 if (!pskb_may_pull(rx->skb, hdrlen + IEEE80211_CCMP_HDR_LEN))
 510                         return RX_DROP_UNUSABLE;
 511         } else {
 512                 if (skb_linearize(rx->skb))
 513                         return RX_DROP_UNUSABLE;
 514         }
 515
 516         ccmp_hdr2pn(pn, skb->data + hdrlen);
 517
 518         queue = rx->security_idx;
 519
 520         if (memcmp(pn, key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN) <= 0) {
 521                 key->u.ccmp.replays++;
 522                 return RX_DROP_UNUSABLE;
 523         }
 524
 525         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 526                 u8 aad[2 * AES_BLOCK_SIZE];
 527                 u8 b_0[AES_BLOCK_SIZE];
 528                 /* hardware didn't decrypt/verify MIC */
 529                 ccmp_special_blocks(skb, pn, b_0, aad);
 530
 531                 if (ieee80211_aes_ccm_decrypt(
 532                             key->u.ccmp.tfm, b_0, aad,
 533                             skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
 534                             data_len,
 535                             skb->data + skb->len - IEEE80211_CCMP_MIC_LEN))
 536                         return RX_DROP_UNUSABLE;
 537         }
 538
 539         memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
 540
 541         /* Remove CCMP header and MIC */
 542         if (pskb_trim(skb, skb->len - IEEE80211_CCMP_MIC_LEN))
 543                 return RX_DROP_UNUSABLE;
 544         memmove(skb->data + IEEE80211_CCMP_HDR_LEN, skb->data, hdrlen);
 545         skb_pull(skb, IEEE80211_CCMP_HDR_LEN);
 546
 547         return RX_CONTINUE;
 548 }
 549
 550 static ieee80211_tx_result
 551 ieee80211_crypto_cs_encrypt(struct ieee80211_tx_data *tx,
 552                             struct sk_buff *skb)
 553 {
 554         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 555         struct ieee80211_key *key = tx->key;
 556         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 557         const struct ieee80211_cipher_scheme *cs = key->sta->cipher_scheme;
 558         int hdrlen;
 559         u8 *pos;
 560
 561         if (info->control.hw_key &&
 562             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 563                 /* hwaccel has no need for preallocated head room */
 564                 return TX_CONTINUE;
 565         }
 566
 567         if (unlikely(skb_headroom(skb) < cs->hdr_len &&
 568                      pskb_expand_head(skb, cs->hdr_len, 0, GFP_ATOMIC)))
 569                 return TX_DROP;
 570
 571         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 572
 573         pos = skb_push(skb, cs->hdr_len);
 574         memmove(pos, pos + cs->hdr_len, hdrlen);
 575         skb_set_network_header(skb, skb_network_offset(skb) + cs->hdr_len);
 576
 577         return TX_CONTINUE;
 578 }
 579
 580 static inline int ieee80211_crypto_cs_pn_compare(u8 *pn1, u8 *pn2, int len)
 581 {
 582         int i;
 583
 584         /* pn is little endian */
 585         for (i = len - 1; i >= 0; i--) {
 586                 if (pn1[i] < pn2[i])
 587                         return -1;
 588                 else if (pn1[i] > pn2[i])
 589                         return 1;
 590         }
 591
 592         return 0;
 593 }
 594
 595 static ieee80211_rx_result
 596 ieee80211_crypto_cs_decrypt(struct ieee80211_rx_data *rx)
 597 {
 598         struct ieee80211_key *key = rx->key;
 599         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 600         const struct ieee80211_cipher_scheme *cs = NULL;
 601         int hdrlen = ieee80211_hdrlen(hdr->frame_control);
 602         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
 603         int data_len;
 604         u8 *rx_pn;
 605         u8 *skb_pn;
 606         u8 qos_tid;
 607
 608         if (!rx->sta || !rx->sta->cipher_scheme ||
 609             !(status->flag & RX_FLAG_DECRYPTED))
 610                 return RX_DROP_UNUSABLE;
 611
 612         if (!ieee80211_is_data(hdr->frame_control))
 613                 return RX_CONTINUE;
 614
 615         cs = rx->sta->cipher_scheme;
 616
 617         data_len = rx->skb->len - hdrlen - cs->hdr_len;
 618
 619         if (data_len < 0)
 620                 return RX_DROP_UNUSABLE;
 621
 622         if (ieee80211_is_data_qos(hdr->frame_control))
 623                 qos_tid = *ieee80211_get_qos_ctl(hdr) &
 624                                 IEEE80211_QOS_CTL_TID_MASK;
 625         else
 626                 qos_tid = 0;
 627
 628         if (skb_linearize(rx->skb))
 629                 return RX_DROP_UNUSABLE;
 630
 631         hdr = (struct ieee80211_hdr *)rx->skb->data;
 632
 633         rx_pn = key->u.gen.rx_pn[qos_tid];
 634         skb_pn = rx->skb->data + hdrlen + cs->pn_off;
 635
 636         if (ieee80211_crypto_cs_pn_compare(skb_pn, rx_pn, cs->pn_len) <= 0)
 637                 return RX_DROP_UNUSABLE;
 638
 639         memcpy(rx_pn, skb_pn, cs->pn_len);
 640
 641         /* remove security header and MIC */
 642         if (pskb_trim(rx->skb, rx->skb->len - cs->mic_len))
 643                 return RX_DROP_UNUSABLE;
 644
 645         memmove(rx->skb->data + cs->hdr_len, rx->skb->data, hdrlen);
 646         skb_pull(rx->skb, cs->hdr_len);
 647
 648         return RX_CONTINUE;
 649 }
 650
 651 static void bip_aad(struct sk_buff *skb, u8 *aad)
 652 {
 653         __le16 mask_fc;
 654         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 655
 656         /* BIP AAD: FC(masked) || A1 || A2 || A3 */
 657
 658         /* FC type/subtype */
 659         /* Mask FC Retry, PwrMgt, MoreData flags to zero */
 660         mask_fc = hdr->frame_control;
 661         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM |
 662                                 IEEE80211_FCTL_MOREDATA);
 663         put_unaligned(mask_fc, (__le16 *) &aad[0]);
 664         /* A1 || A2 || A3 */
 665         memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN);
 666 }
 667
 668
 669 static inline void bip_ipn_set64(u8 *d, u64 pn)
 670 {
 671         *d++ = pn;
 672         *d++ = pn >> 8;
 673         *d++ = pn >> 16;
 674         *d++ = pn >> 24;
 675         *d++ = pn >> 32;
 676         *d = pn >> 40;
 677 }
 678
 679 static inline void bip_ipn_swap(u8 *d, const u8 *s)
 680 {
 681         *d++ = s[5];
 682         *d++ = s[4];
 683         *d++ = s[3];
 684         *d++ = s[2];
 685         *d++ = s[1];
 686         *d = s[0];
 687 }
 688
 689
 690 ieee80211_tx_result
 691 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 692 {
 693         struct sk_buff *skb;
 694         struct ieee80211_tx_info *info;
 695         struct ieee80211_key *key = tx->key;
 696         struct ieee80211_mmie *mmie;
 697         u8 aad[20];
 698         u64 pn64;
 699
 700         if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
 701                 return TX_DROP;
 702
 703         skb = skb_peek(&tx->skbs);
 704
 705         info = IEEE80211_SKB_CB(skb);
 706
 707         if (info->control.hw_key)
 708                 return TX_CONTINUE;
 709
 710         if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 711                 return TX_DROP;
 712
 713         mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
 714         mmie->element_id = WLAN_EID_MMIE;
 715         mmie->length = sizeof(*mmie) - 2;
 716         mmie->key_id = cpu_to_le16(key->conf.keyidx);
 717
 718         /* PN = PN + 1 */
 719         pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
 720
 721         bip_ipn_set64(mmie->sequence_number, pn64);
 722
 723         bip_aad(skb, aad);
 724
 725         /*
 726          * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
 727          */
 728         ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 729                            skb->data + 24, skb->len - 24, mmie->mic);
 730
 731         return TX_CONTINUE;
 732 }
 733
 734
 735 ieee80211_rx_result
 736 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 737 {
 738         struct sk_buff *skb = rx->skb;
 739         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 740         struct ieee80211_key *key = rx->key;
 741         struct ieee80211_mmie *mmie;
 742         u8 aad[20], mic[8], ipn[6];
 743         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 744
 745         if (!ieee80211_is_mgmt(hdr->frame_control))
 746                 return RX_CONTINUE;
 747
 748         /* management frames are already linear */
 749
 750         if (skb->len < 24 + sizeof(*mmie))
 751                 return RX_DROP_UNUSABLE;
 752
 753         mmie = (struct ieee80211_mmie *)
 754                 (skb->data + skb->len - sizeof(*mmie));
 755         if (mmie->element_id != WLAN_EID_MMIE ||
 756             mmie->length != sizeof(*mmie) - 2)
 757                 return RX_DROP_UNUSABLE; /* Invalid MMIE */
 758
 759         bip_ipn_swap(ipn, mmie->sequence_number);
 760
 761         if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
 762                 key->u.aes_cmac.replays++;
 763                 return RX_DROP_UNUSABLE;
 764         }
 765
 766         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 767                 /* hardware didn't decrypt/verify MIC */
 768                 bip_aad(skb, aad);
 769                 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 770                                    skb->data + 24, skb->len - 24, mic);
 771                 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
 772                         key->u.aes_cmac.icverrors++;
 773                         return RX_DROP_UNUSABLE;
 774                 }
 775         }
 776
 777         memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
 778
 779         /* Remove MMIE */
 780         skb_trim(skb, skb->len - sizeof(*mmie));
 781
 782         return RX_CONTINUE;
 783 }
 784
 785 ieee80211_tx_result
 786 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
 787 {
 788         struct sk_buff *skb;
 789         struct ieee80211_tx_info *info = NULL;
 790         ieee80211_tx_result res;
 791
 792         skb_queue_walk(&tx->skbs, skb) {
 793                 info  = IEEE80211_SKB_CB(skb);
 794
 795                 /* handle hw-only algorithm */
 796                 if (!info->control.hw_key)
 797                         return TX_DROP;
 798
 799                 if (tx->key->sta->cipher_scheme) {
 800                         res = ieee80211_crypto_cs_encrypt(tx, skb);
 801                         if (res != TX_CONTINUE)
 802                                 return res;
 803                 }
 804         }
 805
 806         ieee80211_tx_set_protected(tx);
 807
 808         return TX_CONTINUE;
 809 }
 810
 811 ieee80211_rx_result
 812 ieee80211_crypto_hw_decrypt(struct ieee80211_rx_data *rx)
 813 {
 814         if (rx->sta && rx->sta->cipher_scheme)
 815                 return ieee80211_crypto_cs_decrypt(rx);
 816
 817         return RX_DROP_UNUSABLE;
 818 }