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                                 int encrypted)
 306 {
 307         __le16 mask_fc;
 308         int a4_included, mgmt;
 309         u8 qos_tid;
 310         u16 len_a;
 311         unsigned int hdrlen;
 312         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 313
 314         /*
 315          * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
 316          * Retry, PwrMgt, MoreData; set Protected
 317          */
 318         mgmt = ieee80211_is_mgmt(hdr->frame_control);
 319         mask_fc = hdr->frame_control;
 320         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
 321                                 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
 322         if (!mgmt)
 323                 mask_fc &= ~cpu_to_le16(0x0070);
 324         mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 325
 326         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 327         len_a = hdrlen - 2;
 328         a4_included = ieee80211_has_a4(hdr->frame_control);
 329
 330         if (ieee80211_is_data_qos(hdr->frame_control))
 331                 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 332         else
 333                 qos_tid = 0;
 334
 335         /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
 336          * mode authentication are not allowed to collide, yet both are derived
 337          * from this vector b_0. We only set L := 1 here to indicate that the
 338          * data size can be represented in (L+1) bytes. The CCM layer will take
 339          * care of storing the data length in the top (L+1) bytes and setting
 340          * and clearing the other bits as is required to derive the two IVs.
 341          */
 342         b_0[0] = 0x1;
 343
 344         /* Nonce: Nonce Flags | A2 | PN
 345          * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
 346          */
 347         b_0[1] = qos_tid | (mgmt << 4);
 348         memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
 349         memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN);
 350
 351         /* AAD (extra authenticate-only data) / masked 802.11 header
 352          * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
 353         put_unaligned_be16(len_a, &aad[0]);
 354         put_unaligned(mask_fc, (__le16 *)&aad[2]);
 355         memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
 356
 357         /* Mask Seq#, leave Frag# */
 358         aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
 359         aad[23] = 0;
 360
 361         if (a4_included) {
 362                 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
 363                 aad[30] = qos_tid;
 364                 aad[31] = 0;
 365         } else {
 366                 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
 367                 aad[24] = qos_tid;
 368         }
 369 }
 370
 371
 372 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
 373 {
 374         hdr[0] = pn[5];
 375         hdr[1] = pn[4];
 376         hdr[2] = 0;
 377         hdr[3] = 0x20 | (key_id << 6);
 378         hdr[4] = pn[3];
 379         hdr[5] = pn[2];
 380         hdr[6] = pn[1];
 381         hdr[7] = pn[0];
 382 }
 383
 384
 385 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
 386 {
 387         pn[0] = hdr[7];
 388         pn[1] = hdr[6];
 389         pn[2] = hdr[5];
 390         pn[3] = hdr[4];
 391         pn[4] = hdr[1];
 392         pn[5] = hdr[0];
 393 }
 394
 395
 396 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 397 {
 398         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 399         struct ieee80211_key *key = tx->key;
 400         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 401         int hdrlen, len, tail;
 402         u8 *pos;
 403         u8 pn[6];
 404         u64 pn64;
 405         u8 aad[2 * AES_BLOCK_SIZE];
 406         u8 b_0[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 = IEEE80211_CCMP_MIC_LEN;
 425
 426         if (WARN_ON(skb_tailroom(skb) < tail ||
 427                     skb_headroom(skb) < IEEE80211_CCMP_HDR_LEN))
 428                 return -1;
 429
 430         pos = skb_push(skb, IEEE80211_CCMP_HDR_LEN);
 431         memmove(pos, pos + IEEE80211_CCMP_HDR_LEN, hdrlen);
 432         skb_set_network_header(skb, skb_network_offset(skb) +
 433                                     IEEE80211_CCMP_HDR_LEN);
 434
 435         /* the HW only needs room for the IV, but not the actual IV */
 436         if (info->control.hw_key &&
 437             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 438                 return 0;
 439
 440         hdr = (struct ieee80211_hdr *) pos;
 441         pos += hdrlen;
 442
 443         pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
 444
 445         pn[5] = pn64;
 446         pn[4] = pn64 >> 8;
 447         pn[3] = pn64 >> 16;
 448         pn[2] = pn64 >> 24;
 449         pn[1] = pn64 >> 32;
 450         pn[0] = pn64 >> 40;
 451
 452         ccmp_pn2hdr(pos, pn, key->conf.keyidx);
 453
 454         /* hwaccel - with software CCMP header */
 455         if (info->control.hw_key)
 456                 return 0;
 457
 458         pos += IEEE80211_CCMP_HDR_LEN;
 459         ccmp_special_blocks(skb, pn, b_0, aad, 0);
 460         ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len,
 461                                   skb_put(skb, IEEE80211_CCMP_MIC_LEN));
 462
 463         return 0;
 464 }
 465
 466
 467 ieee80211_tx_result
 468 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
 469 {
 470         struct sk_buff *skb;
 471
 472         ieee80211_tx_set_protected(tx);
 473
 474         skb_queue_walk(&tx->skbs, skb) {
 475                 if (ccmp_encrypt_skb(tx, skb) < 0)
 476                         return TX_DROP;
 477         }
 478
 479         return TX_CONTINUE;
 480 }
 481
 482
 483 ieee80211_rx_result
 484 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
 485 {
 486         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 487         int hdrlen;
 488         struct ieee80211_key *key = rx->key;
 489         struct sk_buff *skb = rx->skb;
 490         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 491         u8 pn[IEEE80211_CCMP_PN_LEN];
 492         int data_len;
 493         int queue;
 494
 495         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 496
 497         if (!ieee80211_is_data(hdr->frame_control) &&
 498             !ieee80211_is_robust_mgmt_frame(hdr))
 499                 return RX_CONTINUE;
 500
 501         data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN -
 502                    IEEE80211_CCMP_MIC_LEN;
 503         if (!rx->sta || data_len < 0)
 504                 return RX_DROP_UNUSABLE;
 505
 506         if (status->flag & RX_FLAG_DECRYPTED) {
 507                 if (!pskb_may_pull(rx->skb, hdrlen + IEEE80211_CCMP_HDR_LEN))
 508                         return RX_DROP_UNUSABLE;
 509         } else {
 510                 if (skb_linearize(rx->skb))
 511                         return RX_DROP_UNUSABLE;
 512         }
 513
 514         ccmp_hdr2pn(pn, skb->data + hdrlen);
 515
 516         queue = rx->security_idx;
 517
 518         if (memcmp(pn, key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN) <= 0) {
 519                 key->u.ccmp.replays++;
 520                 return RX_DROP_UNUSABLE;
 521         }
 522
 523         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 524                 u8 aad[2 * AES_BLOCK_SIZE];
 525                 u8 b_0[AES_BLOCK_SIZE];
 526                 /* hardware didn't decrypt/verify MIC */
 527                 ccmp_special_blocks(skb, pn, b_0, aad, 1);
 528
 529                 if (ieee80211_aes_ccm_decrypt(
 530                             key->u.ccmp.tfm, b_0, aad,
 531                             skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
 532                             data_len,
 533                             skb->data + skb->len - IEEE80211_CCMP_MIC_LEN))
 534                         return RX_DROP_UNUSABLE;
 535         }
 536
 537         memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
 538
 539         /* Remove CCMP header and MIC */
 540         if (pskb_trim(skb, skb->len - IEEE80211_CCMP_MIC_LEN))
 541                 return RX_DROP_UNUSABLE;
 542         memmove(skb->data + IEEE80211_CCMP_HDR_LEN, skb->data, hdrlen);
 543         skb_pull(skb, IEEE80211_CCMP_HDR_LEN);
 544
 545         return RX_CONTINUE;
 546 }
 547
 548 static ieee80211_tx_result
 549 ieee80211_crypto_cs_encrypt(struct ieee80211_tx_data *tx,
 550                             struct sk_buff *skb)
 551 {
 552         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 553         struct ieee80211_key *key = tx->key;
 554         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 555         const struct ieee80211_cipher_scheme *cs = key->sta->cipher_scheme;
 556         int hdrlen;
 557         u8 *pos;
 558
 559         if (info->control.hw_key &&
 560             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 561                 /* hwaccel has no need for preallocated head room */
 562                 return TX_CONTINUE;
 563         }
 564
 565         if (unlikely(skb_headroom(skb) < cs->hdr_len &&
 566                      pskb_expand_head(skb, cs->hdr_len, 0, GFP_ATOMIC)))
 567                 return TX_DROP;
 568
 569         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 570
 571         pos = skb_push(skb, cs->hdr_len);
 572         memmove(pos, pos + cs->hdr_len, hdrlen);
 573         skb_set_network_header(skb, skb_network_offset(skb) + cs->hdr_len);
 574
 575         return TX_CONTINUE;
 576 }
 577
 578 static inline int ieee80211_crypto_cs_pn_compare(u8 *pn1, u8 *pn2, int len)
 579 {
 580         int i;
 581
 582         /* pn is little endian */
 583         for (i = len - 1; i >= 0; i--) {
 584                 if (pn1[i] < pn2[i])
 585                         return -1;
 586                 else if (pn1[i] > pn2[i])
 587                         return 1;
 588         }
 589
 590         return 0;
 591 }
 592
 593 static ieee80211_rx_result
 594 ieee80211_crypto_cs_decrypt(struct ieee80211_rx_data *rx)
 595 {
 596         struct ieee80211_key *key = rx->key;
 597         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 598         const struct ieee80211_cipher_scheme *cs = NULL;
 599         int hdrlen = ieee80211_hdrlen(hdr->frame_control);
 600         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
 601         int data_len;
 602         u8 *rx_pn;
 603         u8 *skb_pn;
 604         u8 qos_tid;
 605
 606         if (!rx->sta || !rx->sta->cipher_scheme ||
 607             !(status->flag & RX_FLAG_DECRYPTED))
 608                 return RX_DROP_UNUSABLE;
 609
 610         if (!ieee80211_is_data(hdr->frame_control))
 611                 return RX_CONTINUE;
 612
 613         cs = rx->sta->cipher_scheme;
 614
 615         data_len = rx->skb->len - hdrlen - cs->hdr_len;
 616
 617         if (data_len < 0)
 618                 return RX_DROP_UNUSABLE;
 619
 620         if (ieee80211_is_data_qos(hdr->frame_control))
 621                 qos_tid = *ieee80211_get_qos_ctl(hdr) &
 622                                 IEEE80211_QOS_CTL_TID_MASK;
 623         else
 624                 qos_tid = 0;
 625
 626         if (skb_linearize(rx->skb))
 627                 return RX_DROP_UNUSABLE;
 628
 629         hdr = (struct ieee80211_hdr *)rx->skb->data;
 630
 631         rx_pn = key->u.gen.rx_pn[qos_tid];
 632         skb_pn = rx->skb->data + hdrlen + cs->pn_off;
 633
 634         if (ieee80211_crypto_cs_pn_compare(skb_pn, rx_pn, cs->pn_len) <= 0)
 635                 return RX_DROP_UNUSABLE;
 636
 637         memcpy(rx_pn, skb_pn, cs->pn_len);
 638
 639         /* remove security header and MIC */
 640         if (pskb_trim(rx->skb, rx->skb->len - cs->mic_len))
 641                 return RX_DROP_UNUSABLE;
 642
 643         memmove(rx->skb->data + cs->hdr_len, rx->skb->data, hdrlen);
 644         skb_pull(rx->skb, cs->hdr_len);
 645
 646         return RX_CONTINUE;
 647 }
 648
 649 static void bip_aad(struct sk_buff *skb, u8 *aad)
 650 {
 651         __le16 mask_fc;
 652         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 653
 654         /* BIP AAD: FC(masked) || A1 || A2 || A3 */
 655
 656         /* FC type/subtype */
 657         /* Mask FC Retry, PwrMgt, MoreData flags to zero */
 658         mask_fc = hdr->frame_control;
 659         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM |
 660                                 IEEE80211_FCTL_MOREDATA);
 661         put_unaligned(mask_fc, (__le16 *) &aad[0]);
 662         /* A1 || A2 || A3 */
 663         memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN);
 664 }
 665
 666
 667 static inline void bip_ipn_set64(u8 *d, u64 pn)
 668 {
 669         *d++ = pn;
 670         *d++ = pn >> 8;
 671         *d++ = pn >> 16;
 672         *d++ = pn >> 24;
 673         *d++ = pn >> 32;
 674         *d = pn >> 40;
 675 }
 676
 677 static inline void bip_ipn_swap(u8 *d, const u8 *s)
 678 {
 679         *d++ = s[5];
 680         *d++ = s[4];
 681         *d++ = s[3];
 682         *d++ = s[2];
 683         *d++ = s[1];
 684         *d = s[0];
 685 }
 686
 687
 688 ieee80211_tx_result
 689 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 690 {
 691         struct sk_buff *skb;
 692         struct ieee80211_tx_info *info;
 693         struct ieee80211_key *key = tx->key;
 694         struct ieee80211_mmie *mmie;
 695         u8 aad[20];
 696         u64 pn64;
 697
 698         if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
 699                 return TX_DROP;
 700
 701         skb = skb_peek(&tx->skbs);
 702
 703         info = IEEE80211_SKB_CB(skb);
 704
 705         if (info->control.hw_key)
 706                 return TX_CONTINUE;
 707
 708         if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 709                 return TX_DROP;
 710
 711         mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
 712         mmie->element_id = WLAN_EID_MMIE;
 713         mmie->length = sizeof(*mmie) - 2;
 714         mmie->key_id = cpu_to_le16(key->conf.keyidx);
 715
 716         /* PN = PN + 1 */
 717         pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
 718
 719         bip_ipn_set64(mmie->sequence_number, pn64);
 720
 721         bip_aad(skb, aad);
 722
 723         /*
 724          * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
 725          */
 726         ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 727                            skb->data + 24, skb->len - 24, mmie->mic);
 728
 729         return TX_CONTINUE;
 730 }
 731
 732
 733 ieee80211_rx_result
 734 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 735 {
 736         struct sk_buff *skb = rx->skb;
 737         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 738         struct ieee80211_key *key = rx->key;
 739         struct ieee80211_mmie *mmie;
 740         u8 aad[20], mic[8], ipn[6];
 741         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 742
 743         if (!ieee80211_is_mgmt(hdr->frame_control))
 744                 return RX_CONTINUE;
 745
 746         /* management frames are already linear */
 747
 748         if (skb->len < 24 + sizeof(*mmie))
 749                 return RX_DROP_UNUSABLE;
 750
 751         mmie = (struct ieee80211_mmie *)
 752                 (skb->data + skb->len - sizeof(*mmie));
 753         if (mmie->element_id != WLAN_EID_MMIE ||
 754             mmie->length != sizeof(*mmie) - 2)
 755                 return RX_DROP_UNUSABLE; /* Invalid MMIE */
 756
 757         bip_ipn_swap(ipn, mmie->sequence_number);
 758
 759         if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
 760                 key->u.aes_cmac.replays++;
 761                 return RX_DROP_UNUSABLE;
 762         }
 763
 764         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 765                 /* hardware didn't decrypt/verify MIC */
 766                 bip_aad(skb, aad);
 767                 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 768                                    skb->data + 24, skb->len - 24, mic);
 769                 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
 770                         key->u.aes_cmac.icverrors++;
 771                         return RX_DROP_UNUSABLE;
 772                 }
 773         }
 774
 775         memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
 776
 777         /* Remove MMIE */
 778         skb_trim(skb, skb->len - sizeof(*mmie));
 779
 780         return RX_CONTINUE;
 781 }
 782
 783 ieee80211_tx_result
 784 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
 785 {
 786         struct sk_buff *skb;
 787         struct ieee80211_tx_info *info = NULL;
 788         ieee80211_tx_result res;
 789
 790         skb_queue_walk(&tx->skbs, skb) {
 791                 info  = IEEE80211_SKB_CB(skb);
 792
 793                 /* handle hw-only algorithm */
 794                 if (!info->control.hw_key)
 795                         return TX_DROP;
 796
 797                 if (tx->key->sta->cipher_scheme) {
 798                         res = ieee80211_crypto_cs_encrypt(tx, skb);
 799                         if (res != TX_CONTINUE)
 800                                 return res;
 801                 }
 802         }
 803
 804         ieee80211_tx_set_protected(tx);
 805
 806         return TX_CONTINUE;
 807 }
 808
 809 ieee80211_rx_result
 810 ieee80211_crypto_hw_decrypt(struct ieee80211_rx_data *rx)
 811 {
 812         if (rx->sta->cipher_scheme)
 813                 return ieee80211_crypto_cs_decrypt(rx);
 814
 815         return RX_DROP_UNUSABLE;
 816 }