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 #include <crypto/algapi.h>
  20
  21 #include "ieee80211_i.h"
  22 #include "michael.h"
  23 #include "tkip.h"
  24 #include "aes_ccm.h"
  25 #include "aes_cmac.h"
  26 #include "wpa.h"
  27
  28 ieee80211_tx_result
  29 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
  30 {
  31         u8 *data, *key, *mic;
  32         size_t data_len;
  33         unsigned int hdrlen;
  34         struct ieee80211_hdr *hdr;
  35         struct sk_buff *skb = tx->skb;
  36         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  37         int tail;
  38
  39         hdr = (struct ieee80211_hdr *)skb->data;
  40         if (!tx->key || tx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
  41             skb->len < 24 || !ieee80211_is_data_present(hdr->frame_control))
  42                 return TX_CONTINUE;
  43
  44         hdrlen = ieee80211_hdrlen(hdr->frame_control);
  45         if (skb->len < hdrlen)
  46                 return TX_DROP;
  47
  48         data = skb->data + hdrlen;
  49         data_len = skb->len - hdrlen;
  50
  51         if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) {
  52                 /* Need to use software crypto for the test */
  53                 info->control.hw_key = NULL;
  54         }
  55
  56         if (info->control.hw_key &&
  57             (info->flags & IEEE80211_TX_CTL_DONTFRAG ||
  58              tx->local->ops->set_frag_threshold) &&
  59             !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
  60                 /* hwaccel - with no need for SW-generated MMIC */
  61                 return TX_CONTINUE;
  62         }
  63
  64         tail = MICHAEL_MIC_LEN;
  65         if (!info->control.hw_key)
  66                 tail += IEEE80211_TKIP_ICV_LEN;
  67
  68         if (WARN(skb_tailroom(skb) < tail ||
  69                  skb_headroom(skb) < IEEE80211_TKIP_IV_LEN,
  70                  "mmic: not enough head/tail (%d/%d,%d/%d)\n",
  71                  skb_headroom(skb), IEEE80211_TKIP_IV_LEN,
  72                  skb_tailroom(skb), tail))
  73                 return TX_DROP;
  74
  75         key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY];
  76         mic = skb_put(skb, MICHAEL_MIC_LEN);
  77         michael_mic(key, hdr, data, data_len, mic);
  78         if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE))
  79                 mic[0]++;
  80
  81         return TX_CONTINUE;
  82 }
  83
  84
  85 ieee80211_rx_result
  86 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
  87 {
  88         u8 *data, *key = NULL;
  89         size_t data_len;
  90         unsigned int hdrlen;
  91         u8 mic[MICHAEL_MIC_LEN];
  92         struct sk_buff *skb = rx->skb;
  93         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
  94         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
  95
  96         /*
  97          * it makes no sense to check for MIC errors on anything other
  98          * than data frames.
  99          */
 100         if (!ieee80211_is_data_present(hdr->frame_control))
 101                 return RX_CONTINUE;
 102
 103         /*
 104          * No way to verify the MIC if the hardware stripped it or
 105          * the IV with the key index. In this case we have solely rely
 106          * on the driver to set RX_FLAG_MMIC_ERROR in the event of a
 107          * MIC failure report.
 108          */
 109         if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) {
 110                 if (status->flag & RX_FLAG_MMIC_ERROR)
 111                         goto mic_fail_no_key;
 112
 113                 if (!(status->flag & RX_FLAG_IV_STRIPPED) && rx->key &&
 114                     rx->key->conf.cipher == WLAN_CIPHER_SUITE_TKIP)
 115                         goto update_iv;
 116
 117                 return RX_CONTINUE;
 118         }
 119
 120         /*
 121          * Some hardware seems to generate Michael MIC failure reports; even
 122          * though, the frame was not encrypted with TKIP and therefore has no
 123          * MIC. Ignore the flag them to avoid triggering countermeasures.
 124          */
 125         if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
 126             !(status->flag & RX_FLAG_DECRYPTED))
 127                 return RX_CONTINUE;
 128
 129         if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) {
 130                 /*
 131                  * APs with pairwise keys should never receive Michael MIC
 132                  * errors for non-zero keyidx because these are reserved for
 133                  * group keys and only the AP is sending real multicast
 134                  * frames in the BSS.
 135                  */
 136                 return RX_DROP_UNUSABLE;
 137         }
 138
 139         if (status->flag & RX_FLAG_MMIC_ERROR)
 140                 goto mic_fail;
 141
 142         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 143         if (skb->len < hdrlen + MICHAEL_MIC_LEN)
 144                 return RX_DROP_UNUSABLE;
 145
 146         if (skb_linearize(rx->skb))
 147                 return RX_DROP_UNUSABLE;
 148         hdr = (void *)skb->data;
 149
 150         data = skb->data + hdrlen;
 151         data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
 152         key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
 153         michael_mic(key, hdr, data, data_len, mic);
 154         if (crypto_memneq(mic, data + data_len, MICHAEL_MIC_LEN))
 155                 goto mic_fail;
 156
 157         /* remove Michael MIC from payload */
 158         skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
 159
 160 update_iv:
 161         /* update IV in key information to be able to detect replays */
 162         rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32;
 163         rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16;
 164
 165         return RX_CONTINUE;
 166
 167 mic_fail:
 168         rx->key->u.tkip.mic_failures++;
 169
 170 mic_fail_no_key:
 171         /*
 172          * In some cases the key can be unset - e.g. a multicast packet, in
 173          * a driver that supports HW encryption. Send up the key idx only if
 174          * the key is set.
 175          */
 176         mac80211_ev_michael_mic_failure(rx->sdata,
 177                                         rx->key ? rx->key->conf.keyidx : -1,
 178                                         (void *) skb->data, NULL, GFP_ATOMIC);
 179         return RX_DROP_UNUSABLE;
 180 }
 181
 182
 183 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 184 {
 185         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 186         struct ieee80211_key *key = tx->key;
 187         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 188         unsigned int hdrlen;
 189         int len, tail;
 190         u8 *pos;
 191
 192         if (info->control.hw_key &&
 193             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 194             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 195                 /* hwaccel - with no need for software-generated IV */
 196                 return 0;
 197         }
 198
 199         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 200         len = skb->len - hdrlen;
 201
 202         if (info->control.hw_key)
 203                 tail = 0;
 204         else
 205                 tail = IEEE80211_TKIP_ICV_LEN;
 206
 207         if (WARN_ON(skb_tailroom(skb) < tail ||
 208                     skb_headroom(skb) < IEEE80211_TKIP_IV_LEN))
 209                 return -1;
 210
 211         pos = skb_push(skb, IEEE80211_TKIP_IV_LEN);
 212         memmove(pos, pos + IEEE80211_TKIP_IV_LEN, hdrlen);
 213         skb_set_network_header(skb, skb_network_offset(skb) +
 214                                     IEEE80211_TKIP_IV_LEN);
 215         pos += hdrlen;
 216
 217         /* the HW only needs room for the IV, but not the actual IV */
 218         if (info->control.hw_key &&
 219             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 220                 return 0;
 221
 222         /* Increase IV for the frame */
 223         spin_lock(&key->u.tkip.txlock);
 224         key->u.tkip.tx.iv16++;
 225         if (key->u.tkip.tx.iv16 == 0)
 226                 key->u.tkip.tx.iv32++;
 227         pos = ieee80211_tkip_add_iv(pos, key);
 228         spin_unlock(&key->u.tkip.txlock);
 229
 230         /* hwaccel - with software IV */
 231         if (info->control.hw_key)
 232                 return 0;
 233
 234         /* Add room for ICV */
 235         skb_put(skb, IEEE80211_TKIP_ICV_LEN);
 236
 237         return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
 238                                            key, skb, pos, len);
 239 }
 240
 241
 242 ieee80211_tx_result
 243 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
 244 {
 245         struct sk_buff *skb;
 246
 247         ieee80211_tx_set_protected(tx);
 248
 249         skb_queue_walk(&tx->skbs, skb) {
 250                 if (tkip_encrypt_skb(tx, skb) < 0)
 251                         return TX_DROP;
 252         }
 253
 254         return TX_CONTINUE;
 255 }
 256
 257
 258 ieee80211_rx_result
 259 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
 260 {
 261         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 262         int hdrlen, res, hwaccel = 0;
 263         struct ieee80211_key *key = rx->key;
 264         struct sk_buff *skb = rx->skb;
 265         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 266
 267         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 268
 269         if (!ieee80211_is_data(hdr->frame_control))
 270                 return RX_CONTINUE;
 271
 272         if (!rx->sta || skb->len - hdrlen < 12)
 273                 return RX_DROP_UNUSABLE;
 274
 275         /* it may be possible to optimize this a bit more */
 276         if (skb_linearize(rx->skb))
 277                 return RX_DROP_UNUSABLE;
 278         hdr = (void *)skb->data;
 279
 280         /*
 281          * Let TKIP code verify IV, but skip decryption.
 282          * In the case where hardware checks the IV as well,
 283          * we don't even get here, see ieee80211_rx_h_decrypt()
 284          */
 285         if (status->flag & RX_FLAG_DECRYPTED)
 286                 hwaccel = 1;
 287
 288         res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
 289                                           key, skb->data + hdrlen,
 290                                           skb->len - hdrlen, rx->sta->sta.addr,
 291                                           hdr->addr1, hwaccel, rx->security_idx,
 292                                           &rx->tkip_iv32,
 293                                           &rx->tkip_iv16);
 294         if (res != TKIP_DECRYPT_OK)
 295                 return RX_DROP_UNUSABLE;
 296
 297         /* Trim ICV */
 298         skb_trim(skb, skb->len - IEEE80211_TKIP_ICV_LEN);
 299
 300         /* Remove IV */
 301         memmove(skb->data + IEEE80211_TKIP_IV_LEN, skb->data, hdrlen);
 302         skb_pull(skb, IEEE80211_TKIP_IV_LEN);
 303
 304         return RX_CONTINUE;
 305 }
 306
 307
 308 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad)
 309 {
 310         __le16 mask_fc;
 311         int a4_included, mgmt;
 312         u8 qos_tid;
 313         u16 len_a;
 314         unsigned int hdrlen;
 315         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 316
 317         /*
 318          * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
 319          * Retry, PwrMgt, MoreData; set Protected
 320          */
 321         mgmt = ieee80211_is_mgmt(hdr->frame_control);
 322         mask_fc = hdr->frame_control;
 323         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
 324                                 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
 325         if (!mgmt)
 326                 mask_fc &= ~cpu_to_le16(0x0070);
 327         mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 328
 329         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 330         len_a = hdrlen - 2;
 331         a4_included = ieee80211_has_a4(hdr->frame_control);
 332
 333         if (ieee80211_is_data_qos(hdr->frame_control))
 334                 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 335         else
 336                 qos_tid = 0;
 337
 338         /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
 339          * mode authentication are not allowed to collide, yet both are derived
 340          * from this vector b_0. We only set L := 1 here to indicate that the
 341          * data size can be represented in (L+1) bytes. The CCM layer will take
 342          * care of storing the data length in the top (L+1) bytes and setting
 343          * and clearing the other bits as is required to derive the two IVs.
 344          */
 345         b_0[0] = 0x1;
 346
 347         /* Nonce: Nonce Flags | A2 | PN
 348          * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
 349          */
 350         b_0[1] = qos_tid | (mgmt << 4);
 351         memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
 352         memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN);
 353
 354         /* AAD (extra authenticate-only data) / masked 802.11 header
 355          * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
 356         put_unaligned_be16(len_a, &aad[0]);
 357         put_unaligned(mask_fc, (__le16 *)&aad[2]);
 358         memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
 359
 360         /* Mask Seq#, leave Frag# */
 361         aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
 362         aad[23] = 0;
 363
 364         if (a4_included) {
 365                 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
 366                 aad[30] = qos_tid;
 367                 aad[31] = 0;
 368         } else {
 369                 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
 370                 aad[24] = qos_tid;
 371         }
 372 }
 373
 374
 375 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
 376 {
 377         hdr[0] = pn[5];
 378         hdr[1] = pn[4];
 379         hdr[2] = 0;
 380         hdr[3] = 0x20 | (key_id << 6);
 381         hdr[4] = pn[3];
 382         hdr[5] = pn[2];
 383         hdr[6] = pn[1];
 384         hdr[7] = pn[0];
 385 }
 386
 387
 388 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
 389 {
 390         pn[0] = hdr[7];
 391         pn[1] = hdr[6];
 392         pn[2] = hdr[5];
 393         pn[3] = hdr[4];
 394         pn[4] = hdr[1];
 395         pn[5] = hdr[0];
 396 }
 397
 398
 399 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 400 {
 401         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 402         struct ieee80211_key *key = tx->key;
 403         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 404         int hdrlen, len, tail;
 405         u8 *pos;
 406         u8 pn[6];
 407         u64 pn64;
 408         u8 aad[2 * AES_BLOCK_SIZE];
 409         u8 b_0[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             !((info->control.hw_key->flags &
 415                IEEE80211_KEY_FLAG_GENERATE_IV_MGMT) &&
 416               ieee80211_is_mgmt(hdr->frame_control))) {
 417                 /*
 418                  * hwaccel has no need for preallocated room for CCMP
 419                  * header or MIC fields
 420                  */
 421                 return 0;
 422         }
 423
 424         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 425         len = skb->len - hdrlen;
 426
 427         if (info->control.hw_key)
 428                 tail = 0;
 429         else
 430                 tail = IEEE80211_CCMP_MIC_LEN;
 431
 432         if (WARN_ON(skb_tailroom(skb) < tail ||
 433                     skb_headroom(skb) < IEEE80211_CCMP_HDR_LEN))
 434                 return -1;
 435
 436         pos = skb_push(skb, IEEE80211_CCMP_HDR_LEN);
 437         memmove(pos, pos + IEEE80211_CCMP_HDR_LEN, hdrlen);
 438         skb_set_network_header(skb, skb_network_offset(skb) +
 439                                     IEEE80211_CCMP_HDR_LEN);
 440
 441         /* the HW only needs room for the IV, but not the actual IV */
 442         if (info->control.hw_key &&
 443             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 444                 return 0;
 445
 446         hdr = (struct ieee80211_hdr *) pos;
 447         pos += hdrlen;
 448
 449         pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
 450
 451         pn[5] = pn64;
 452         pn[4] = pn64 >> 8;
 453         pn[3] = pn64 >> 16;
 454         pn[2] = pn64 >> 24;
 455         pn[1] = pn64 >> 32;
 456         pn[0] = pn64 >> 40;
 457
 458         ccmp_pn2hdr(pos, pn, key->conf.keyidx);
 459
 460         /* hwaccel - with software CCMP header */
 461         if (info->control.hw_key)
 462                 return 0;
 463
 464         pos += IEEE80211_CCMP_HDR_LEN;
 465         ccmp_special_blocks(skb, pn, b_0, aad);
 466         ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len,
 467                                   skb_put(skb, IEEE80211_CCMP_MIC_LEN));
 468
 469         return 0;
 470 }
 471
 472
 473 ieee80211_tx_result
 474 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
 475 {
 476         struct sk_buff *skb;
 477
 478         ieee80211_tx_set_protected(tx);
 479
 480         skb_queue_walk(&tx->skbs, skb) {
 481                 if (ccmp_encrypt_skb(tx, skb) < 0)
 482                         return TX_DROP;
 483         }
 484
 485         return TX_CONTINUE;
 486 }
 487
 488
 489 ieee80211_rx_result
 490 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
 491 {
 492         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 493         int hdrlen;
 494         struct ieee80211_key *key = rx->key;
 495         struct sk_buff *skb = rx->skb;
 496         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 497         u8 pn[IEEE80211_CCMP_PN_LEN];
 498         int data_len;
 499         int queue;
 500
 501         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 502
 503         if (!ieee80211_is_data(hdr->frame_control) &&
 504             !ieee80211_is_robust_mgmt_frame(skb))
 505                 return RX_CONTINUE;
 506
 507         data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN -
 508                    IEEE80211_CCMP_MIC_LEN;
 509         if (!rx->sta || data_len < 0)
 510                 return RX_DROP_UNUSABLE;
 511
 512         if (status->flag & RX_FLAG_DECRYPTED) {
 513                 if (!pskb_may_pull(rx->skb, hdrlen + IEEE80211_CCMP_HDR_LEN))
 514                         return RX_DROP_UNUSABLE;
 515         } else {
 516                 if (skb_linearize(rx->skb))
 517                         return RX_DROP_UNUSABLE;
 518         }
 519
 520         ccmp_hdr2pn(pn, skb->data + hdrlen);
 521
 522         queue = rx->security_idx;
 523
 524         if (memcmp(pn, key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN) <= 0) {
 525                 key->u.ccmp.replays++;
 526                 return RX_DROP_UNUSABLE;
 527         }
 528
 529         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 530                 u8 aad[2 * AES_BLOCK_SIZE];
 531                 u8 b_0[AES_BLOCK_SIZE];
 532                 /* hardware didn't decrypt/verify MIC */
 533                 ccmp_special_blocks(skb, pn, b_0, aad);
 534
 535                 if (ieee80211_aes_ccm_decrypt(
 536                             key->u.ccmp.tfm, b_0, aad,
 537                             skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
 538                             data_len,
 539                             skb->data + skb->len - IEEE80211_CCMP_MIC_LEN))
 540                         return RX_DROP_UNUSABLE;
 541         }
 542
 543         memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
 544
 545         /* Remove CCMP header and MIC */
 546         if (pskb_trim(skb, skb->len - IEEE80211_CCMP_MIC_LEN))
 547                 return RX_DROP_UNUSABLE;
 548         memmove(skb->data + IEEE80211_CCMP_HDR_LEN, skb->data, hdrlen);
 549         skb_pull(skb, IEEE80211_CCMP_HDR_LEN);
 550
 551         return RX_CONTINUE;
 552 }
 553
 554 static ieee80211_tx_result
 555 ieee80211_crypto_cs_encrypt(struct ieee80211_tx_data *tx,
 556                             struct sk_buff *skb)
 557 {
 558         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 559         struct ieee80211_key *key = tx->key;
 560         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 561         const struct ieee80211_cipher_scheme *cs = key->sta->cipher_scheme;
 562         int hdrlen;
 563         u8 *pos;
 564
 565         if (info->control.hw_key &&
 566             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 567                 /* hwaccel has no need for preallocated head room */
 568                 return TX_CONTINUE;
 569         }
 570
 571         if (unlikely(skb_headroom(skb) < cs->hdr_len &&
 572                      pskb_expand_head(skb, cs->hdr_len, 0, GFP_ATOMIC)))
 573                 return TX_DROP;
 574
 575         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 576
 577         pos = skb_push(skb, cs->hdr_len);
 578         memmove(pos, pos + cs->hdr_len, hdrlen);
 579         skb_set_network_header(skb, skb_network_offset(skb) + cs->hdr_len);
 580
 581         return TX_CONTINUE;
 582 }
 583
 584 static inline int ieee80211_crypto_cs_pn_compare(u8 *pn1, u8 *pn2, int len)
 585 {
 586         int i;
 587
 588         /* pn is little endian */
 589         for (i = len - 1; i >= 0; i--) {
 590                 if (pn1[i] < pn2[i])
 591                         return -1;
 592                 else if (pn1[i] > pn2[i])
 593                         return 1;
 594         }
 595
 596         return 0;
 597 }
 598
 599 static ieee80211_rx_result
 600 ieee80211_crypto_cs_decrypt(struct ieee80211_rx_data *rx)
 601 {
 602         struct ieee80211_key *key = rx->key;
 603         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 604         const struct ieee80211_cipher_scheme *cs = NULL;
 605         int hdrlen = ieee80211_hdrlen(hdr->frame_control);
 606         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
 607         int data_len;
 608         u8 *rx_pn;
 609         u8 *skb_pn;
 610         u8 qos_tid;
 611
 612         if (!rx->sta || !rx->sta->cipher_scheme ||
 613             !(status->flag & RX_FLAG_DECRYPTED))
 614                 return RX_DROP_UNUSABLE;
 615
 616         if (!ieee80211_is_data(hdr->frame_control))
 617                 return RX_CONTINUE;
 618
 619         cs = rx->sta->cipher_scheme;
 620
 621         data_len = rx->skb->len - hdrlen - cs->hdr_len;
 622
 623         if (data_len < 0)
 624                 return RX_DROP_UNUSABLE;
 625
 626         if (ieee80211_is_data_qos(hdr->frame_control))
 627                 qos_tid = *ieee80211_get_qos_ctl(hdr) &
 628                                 IEEE80211_QOS_CTL_TID_MASK;
 629         else
 630                 qos_tid = 0;
 631
 632         if (skb_linearize(rx->skb))
 633                 return RX_DROP_UNUSABLE;
 634
 635         hdr = (struct ieee80211_hdr *)rx->skb->data;
 636
 637         rx_pn = key->u.gen.rx_pn[qos_tid];
 638         skb_pn = rx->skb->data + hdrlen + cs->pn_off;
 639
 640         if (ieee80211_crypto_cs_pn_compare(skb_pn, rx_pn, cs->pn_len) <= 0)
 641                 return RX_DROP_UNUSABLE;
 642
 643         memcpy(rx_pn, skb_pn, cs->pn_len);
 644
 645         /* remove security header and MIC */
 646         if (pskb_trim(rx->skb, rx->skb->len - cs->mic_len))
 647                 return RX_DROP_UNUSABLE;
 648
 649         memmove(rx->skb->data + cs->hdr_len, rx->skb->data, hdrlen);
 650         skb_pull(rx->skb, cs->hdr_len);
 651
 652         return RX_CONTINUE;
 653 }
 654
 655 static void bip_aad(struct sk_buff *skb, u8 *aad)
 656 {
 657         __le16 mask_fc;
 658         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 659
 660         /* BIP AAD: FC(masked) || A1 || A2 || A3 */
 661
 662         /* FC type/subtype */
 663         /* Mask FC Retry, PwrMgt, MoreData flags to zero */
 664         mask_fc = hdr->frame_control;
 665         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM |
 666                                 IEEE80211_FCTL_MOREDATA);
 667         put_unaligned(mask_fc, (__le16 *) &aad[0]);
 668         /* A1 || A2 || A3 */
 669         memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN);
 670 }
 671
 672
 673 static inline void bip_ipn_set64(u8 *d, u64 pn)
 674 {
 675         *d++ = pn;
 676         *d++ = pn >> 8;
 677         *d++ = pn >> 16;
 678         *d++ = pn >> 24;
 679         *d++ = pn >> 32;
 680         *d = pn >> 40;
 681 }
 682
 683 static inline void bip_ipn_swap(u8 *d, const u8 *s)
 684 {
 685         *d++ = s[5];
 686         *d++ = s[4];
 687         *d++ = s[3];
 688         *d++ = s[2];
 689         *d++ = s[1];
 690         *d = s[0];
 691 }
 692
 693
 694 ieee80211_tx_result
 695 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 696 {
 697         struct sk_buff *skb;
 698         struct ieee80211_tx_info *info;
 699         struct ieee80211_key *key = tx->key;
 700         struct ieee80211_mmie *mmie;
 701         u8 aad[20];
 702         u64 pn64;
 703
 704         if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
 705                 return TX_DROP;
 706
 707         skb = skb_peek(&tx->skbs);
 708
 709         info = IEEE80211_SKB_CB(skb);
 710
 711         if (info->control.hw_key)
 712                 return TX_CONTINUE;
 713
 714         if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 715                 return TX_DROP;
 716
 717         mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
 718         mmie->element_id = WLAN_EID_MMIE;
 719         mmie->length = sizeof(*mmie) - 2;
 720         mmie->key_id = cpu_to_le16(key->conf.keyidx);
 721
 722         /* PN = PN + 1 */
 723         pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
 724
 725         bip_ipn_set64(mmie->sequence_number, pn64);
 726
 727         bip_aad(skb, aad);
 728
 729         /*
 730          * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
 731          */
 732         ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 733                            skb->data + 24, skb->len - 24, mmie->mic);
 734
 735         return TX_CONTINUE;
 736 }
 737
 738
 739 ieee80211_rx_result
 740 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 741 {
 742         struct sk_buff *skb = rx->skb;
 743         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 744         struct ieee80211_key *key = rx->key;
 745         struct ieee80211_mmie *mmie;
 746         u8 aad[20], mic[8], ipn[6];
 747         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 748
 749         if (!ieee80211_is_mgmt(hdr->frame_control))
 750                 return RX_CONTINUE;
 751
 752         /* management frames are already linear */
 753
 754         if (skb->len < 24 + sizeof(*mmie))
 755                 return RX_DROP_UNUSABLE;
 756
 757         mmie = (struct ieee80211_mmie *)
 758                 (skb->data + skb->len - sizeof(*mmie));
 759         if (mmie->element_id != WLAN_EID_MMIE ||
 760             mmie->length != sizeof(*mmie) - 2)
 761                 return RX_DROP_UNUSABLE; /* Invalid MMIE */
 762
 763         bip_ipn_swap(ipn, mmie->sequence_number);
 764
 765         if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
 766                 key->u.aes_cmac.replays++;
 767                 return RX_DROP_UNUSABLE;
 768         }
 769
 770         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 771                 /* hardware didn't decrypt/verify MIC */
 772                 bip_aad(skb, aad);
 773                 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 774                                    skb->data + 24, skb->len - 24, mic);
 775                 if (crypto_memneq(mic, mmie->mic, sizeof(mmie->mic))) {
 776                         key->u.aes_cmac.icverrors++;
 777                         return RX_DROP_UNUSABLE;
 778                 }
 779         }
 780
 781         memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
 782
 783         /* Remove MMIE */
 784         skb_trim(skb, skb->len - sizeof(*mmie));
 785
 786         return RX_CONTINUE;
 787 }
 788
 789 ieee80211_tx_result
 790 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
 791 {
 792         struct sk_buff *skb;
 793         struct ieee80211_tx_info *info = NULL;
 794         ieee80211_tx_result res;
 795
 796         skb_queue_walk(&tx->skbs, skb) {
 797                 info  = IEEE80211_SKB_CB(skb);
 798
 799                 /* handle hw-only algorithm */
 800                 if (!info->control.hw_key)
 801                         return TX_DROP;
 802
 803                 if (tx->key->sta->cipher_scheme) {
 804                         res = ieee80211_crypto_cs_encrypt(tx, skb);
 805                         if (res != TX_CONTINUE)
 806                                 return res;
 807                 }
 808         }
 809
 810         ieee80211_tx_set_protected(tx);
 811
 812         return TX_CONTINUE;
 813 }
 814
 815 ieee80211_rx_result
 816 ieee80211_crypto_hw_decrypt(struct ieee80211_rx_data *rx)
 817 {
 818         if (rx->sta && rx->sta->cipher_scheme)
 819                 return ieee80211_crypto_cs_decrypt(rx);
 820
 821         return RX_DROP_UNUSABLE;
 822 }