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