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 "aes_gcm.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 (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
 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         pos += hdrlen;
 214
 215         /* the HW only needs room for the IV, but not the actual IV */
 216         if (info->control.hw_key &&
 217             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 218                 return 0;
 219
 220         /* Increase IV for the frame */
 221         spin_lock(&key->u.tkip.txlock);
 222         key->u.tkip.tx.iv16++;
 223         if (key->u.tkip.tx.iv16 == 0)
 224                 key->u.tkip.tx.iv32++;
 225         pos = ieee80211_tkip_add_iv(pos, key);
 226         spin_unlock(&key->u.tkip.txlock);
 227
 228         /* hwaccel - with software IV */
 229         if (info->control.hw_key)
 230                 return 0;
 231
 232         /* Add room for ICV */
 233         skb_put(skb, IEEE80211_TKIP_ICV_LEN);
 234
 235         return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
 236                                            key, skb, pos, len);
 237 }
 238
 239
 240 ieee80211_tx_result
 241 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
 242 {
 243         struct sk_buff *skb;
 244
 245         ieee80211_tx_set_protected(tx);
 246
 247         skb_queue_walk(&tx->skbs, skb) {
 248                 if (tkip_encrypt_skb(tx, skb) < 0)
 249                         return TX_DROP;
 250         }
 251
 252         return TX_CONTINUE;
 253 }
 254
 255
 256 ieee80211_rx_result
 257 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
 258 {
 259         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 260         int hdrlen, res, hwaccel = 0;
 261         struct ieee80211_key *key = rx->key;
 262         struct sk_buff *skb = rx->skb;
 263         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 264
 265         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 266
 267         if (!ieee80211_is_data(hdr->frame_control))
 268                 return RX_CONTINUE;
 269
 270         if (!rx->sta || skb->len - hdrlen < 12)
 271                 return RX_DROP_UNUSABLE;
 272
 273         /* it may be possible to optimize this a bit more */
 274         if (skb_linearize(rx->skb))
 275                 return RX_DROP_UNUSABLE;
 276         hdr = (void *)skb->data;
 277
 278         /*
 279          * Let TKIP code verify IV, but skip decryption.
 280          * In the case where hardware checks the IV as well,
 281          * we don't even get here, see ieee80211_rx_h_decrypt()
 282          */
 283         if (status->flag & RX_FLAG_DECRYPTED)
 284                 hwaccel = 1;
 285
 286         res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
 287                                           key, skb->data + hdrlen,
 288                                           skb->len - hdrlen, rx->sta->sta.addr,
 289                                           hdr->addr1, hwaccel, rx->security_idx,
 290                                           &rx->tkip_iv32,
 291                                           &rx->tkip_iv16);
 292         if (res != TKIP_DECRYPT_OK)
 293                 return RX_DROP_UNUSABLE;
 294
 295         /* Trim ICV */
 296         skb_trim(skb, skb->len - IEEE80211_TKIP_ICV_LEN);
 297
 298         /* Remove IV */
 299         memmove(skb->data + IEEE80211_TKIP_IV_LEN, skb->data, hdrlen);
 300         skb_pull(skb, IEEE80211_TKIP_IV_LEN);
 301
 302         return RX_CONTINUE;
 303 }
 304
 305
 306 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad)
 307 {
 308         __le16 mask_fc;
 309         int a4_included, mgmt;
 310         u8 qos_tid;
 311         u16 len_a;
 312         unsigned int hdrlen;
 313         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 314
 315         /*
 316          * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
 317          * Retry, PwrMgt, MoreData; set Protected
 318          */
 319         mgmt = ieee80211_is_mgmt(hdr->frame_control);
 320         mask_fc = hdr->frame_control;
 321         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
 322                                 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
 323         if (!mgmt)
 324                 mask_fc &= ~cpu_to_le16(0x0070);
 325         mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 326
 327         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 328         len_a = hdrlen - 2;
 329         a4_included = ieee80211_has_a4(hdr->frame_control);
 330
 331         if (ieee80211_is_data_qos(hdr->frame_control))
 332                 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 333         else
 334                 qos_tid = 0;
 335
 336         /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
 337          * mode authentication are not allowed to collide, yet both are derived
 338          * from this vector b_0. We only set L := 1 here to indicate that the
 339          * data size can be represented in (L+1) bytes. The CCM layer will take
 340          * care of storing the data length in the top (L+1) bytes and setting
 341          * and clearing the other bits as is required to derive the two IVs.
 342          */
 343         b_0[0] = 0x1;
 344
 345         /* Nonce: Nonce Flags | A2 | PN
 346          * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
 347          */
 348         b_0[1] = qos_tid | (mgmt << 4);
 349         memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
 350         memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN);
 351
 352         /* AAD (extra authenticate-only data) / masked 802.11 header
 353          * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
 354         put_unaligned_be16(len_a, &aad[0]);
 355         put_unaligned(mask_fc, (__le16 *)&aad[2]);
 356         memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
 357
 358         /* Mask Seq#, leave Frag# */
 359         aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
 360         aad[23] = 0;
 361
 362         if (a4_included) {
 363                 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
 364                 aad[30] = qos_tid;
 365                 aad[31] = 0;
 366         } else {
 367                 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
 368                 aad[24] = qos_tid;
 369         }
 370 }
 371
 372
 373 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
 374 {
 375         hdr[0] = pn[5];
 376         hdr[1] = pn[4];
 377         hdr[2] = 0;
 378         hdr[3] = 0x20 | (key_id << 6);
 379         hdr[4] = pn[3];
 380         hdr[5] = pn[2];
 381         hdr[6] = pn[1];
 382         hdr[7] = pn[0];
 383 }
 384
 385
 386 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
 387 {
 388         pn[0] = hdr[7];
 389         pn[1] = hdr[6];
 390         pn[2] = hdr[5];
 391         pn[3] = hdr[4];
 392         pn[4] = hdr[1];
 393         pn[5] = hdr[0];
 394 }
 395
 396
 397 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb,
 398                             unsigned int mic_len)
 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 = 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
 438         /* the HW only needs room for the IV, but not the actual IV */
 439         if (info->control.hw_key &&
 440             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 441                 return 0;
 442
 443         hdr = (struct ieee80211_hdr *) pos;
 444         pos += hdrlen;
 445
 446         pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
 447
 448         pn[5] = pn64;
 449         pn[4] = pn64 >> 8;
 450         pn[3] = pn64 >> 16;
 451         pn[2] = pn64 >> 24;
 452         pn[1] = pn64 >> 32;
 453         pn[0] = pn64 >> 40;
 454
 455         ccmp_pn2hdr(pos, pn, key->conf.keyidx);
 456
 457         /* hwaccel - with software CCMP header */
 458         if (info->control.hw_key)
 459                 return 0;
 460
 461         pos += IEEE80211_CCMP_HDR_LEN;
 462         ccmp_special_blocks(skb, pn, b_0, aad);
 463         ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len,
 464                                   skb_put(skb, mic_len), mic_len);
 465
 466         return 0;
 467 }
 468
 469
 470 ieee80211_tx_result
 471 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx,
 472                               unsigned int mic_len)
 473 {
 474         struct sk_buff *skb;
 475
 476         ieee80211_tx_set_protected(tx);
 477
 478         skb_queue_walk(&tx->skbs, skb) {
 479                 if (ccmp_encrypt_skb(tx, skb, mic_len) < 0)
 480                         return TX_DROP;
 481         }
 482
 483         return TX_CONTINUE;
 484 }
 485
 486
 487 ieee80211_rx_result
 488 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx,
 489                               unsigned int mic_len)
 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 - mic_len;
 507         if (!rx->sta || data_len < 0)
 508                 return RX_DROP_UNUSABLE;
 509
 510         if (status->flag & RX_FLAG_DECRYPTED) {
 511                 if (!pskb_may_pull(rx->skb, hdrlen + IEEE80211_CCMP_HDR_LEN))
 512                         return RX_DROP_UNUSABLE;
 513         } else {
 514                 if (skb_linearize(rx->skb))
 515                         return RX_DROP_UNUSABLE;
 516         }
 517
 518         ccmp_hdr2pn(pn, skb->data + hdrlen);
 519
 520         queue = rx->security_idx;
 521
 522         if (memcmp(pn, key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN) <= 0) {
 523                 key->u.ccmp.replays++;
 524                 return RX_DROP_UNUSABLE;
 525         }
 526
 527         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 528                 u8 aad[2 * AES_BLOCK_SIZE];
 529                 u8 b_0[AES_BLOCK_SIZE];
 530                 /* hardware didn't decrypt/verify MIC */
 531                 ccmp_special_blocks(skb, pn, b_0, aad);
 532
 533                 if (ieee80211_aes_ccm_decrypt(
 534                             key->u.ccmp.tfm, b_0, aad,
 535                             skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
 536                             data_len,
 537                             skb->data + skb->len - mic_len, mic_len))
 538                         return RX_DROP_UNUSABLE;
 539         }
 540
 541         memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
 542
 543         /* Remove CCMP header and MIC */
 544         if (pskb_trim(skb, skb->len - mic_len))
 545                 return RX_DROP_UNUSABLE;
 546         memmove(skb->data + IEEE80211_CCMP_HDR_LEN, skb->data, hdrlen);
 547         skb_pull(skb, IEEE80211_CCMP_HDR_LEN);
 548
 549         return RX_CONTINUE;
 550 }
 551
 552 static void gcmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *j_0, u8 *aad)
 553 {
 554         __le16 mask_fc;
 555         u8 qos_tid;
 556         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 557
 558         memcpy(j_0, hdr->addr2, ETH_ALEN);
 559         memcpy(&j_0[ETH_ALEN], pn, IEEE80211_GCMP_PN_LEN);
 560         j_0[13] = 0;
 561         j_0[14] = 0;
 562         j_0[AES_BLOCK_SIZE - 1] = 0x01;
 563
 564         /* AAD (extra authenticate-only data) / masked 802.11 header
 565          * FC | A1 | A2 | A3 | SC | [A4] | [QC]
 566          */
 567         put_unaligned_be16(ieee80211_hdrlen(hdr->frame_control) - 2, &aad[0]);
 568         /* Mask FC: zero subtype b4 b5 b6 (if not mgmt)
 569          * Retry, PwrMgt, MoreData; set Protected
 570          */
 571         mask_fc = hdr->frame_control;
 572         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
 573                                 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
 574         if (!ieee80211_is_mgmt(hdr->frame_control))
 575                 mask_fc &= ~cpu_to_le16(0x0070);
 576         mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 577
 578         put_unaligned(mask_fc, (__le16 *)&aad[2]);
 579         memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
 580
 581         /* Mask Seq#, leave Frag# */
 582         aad[22] = *((u8 *)&hdr->seq_ctrl) & 0x0f;
 583         aad[23] = 0;
 584
 585         if (ieee80211_is_data_qos(hdr->frame_control))
 586                 qos_tid = *ieee80211_get_qos_ctl(hdr) &
 587                         IEEE80211_QOS_CTL_TID_MASK;
 588         else
 589                 qos_tid = 0;
 590
 591         if (ieee80211_has_a4(hdr->frame_control)) {
 592                 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
 593                 aad[30] = qos_tid;
 594                 aad[31] = 0;
 595         } else {
 596                 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
 597                 aad[24] = qos_tid;
 598         }
 599 }
 600
 601 static inline void gcmp_pn2hdr(u8 *hdr, const u8 *pn, int key_id)
 602 {
 603         hdr[0] = pn[5];
 604         hdr[1] = pn[4];
 605         hdr[2] = 0;
 606         hdr[3] = 0x20 | (key_id << 6);
 607         hdr[4] = pn[3];
 608         hdr[5] = pn[2];
 609         hdr[6] = pn[1];
 610         hdr[7] = pn[0];
 611 }
 612
 613 static inline void gcmp_hdr2pn(u8 *pn, const u8 *hdr)
 614 {
 615         pn[0] = hdr[7];
 616         pn[1] = hdr[6];
 617         pn[2] = hdr[5];
 618         pn[3] = hdr[4];
 619         pn[4] = hdr[1];
 620         pn[5] = hdr[0];
 621 }
 622
 623 static int gcmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 624 {
 625         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 626         struct ieee80211_key *key = tx->key;
 627         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 628         int hdrlen, len, tail;
 629         u8 *pos;
 630         u8 pn[6];
 631         u64 pn64;
 632         u8 aad[2 * AES_BLOCK_SIZE];
 633         u8 j_0[AES_BLOCK_SIZE];
 634
 635         if (info->control.hw_key &&
 636             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 637             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) &&
 638             !((info->control.hw_key->flags &
 639                IEEE80211_KEY_FLAG_GENERATE_IV_MGMT) &&
 640               ieee80211_is_mgmt(hdr->frame_control))) {
 641                 /* hwaccel has no need for preallocated room for GCMP
 642                  * header or MIC fields
 643                  */
 644                 return 0;
 645         }
 646
 647         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 648         len = skb->len - hdrlen;
 649
 650         if (info->control.hw_key)
 651                 tail = 0;
 652         else
 653                 tail = IEEE80211_GCMP_MIC_LEN;
 654
 655         if (WARN_ON(skb_tailroom(skb) < tail ||
 656                     skb_headroom(skb) < IEEE80211_GCMP_HDR_LEN))
 657                 return -1;
 658
 659         pos = skb_push(skb, IEEE80211_GCMP_HDR_LEN);
 660         memmove(pos, pos + IEEE80211_GCMP_HDR_LEN, hdrlen);
 661         skb_set_network_header(skb, skb_network_offset(skb) +
 662                                     IEEE80211_GCMP_HDR_LEN);
 663
 664         /* the HW only needs room for the IV, but not the actual IV */
 665         if (info->control.hw_key &&
 666             (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 667                 return 0;
 668
 669         hdr = (struct ieee80211_hdr *)pos;
 670         pos += hdrlen;
 671
 672         pn64 = atomic64_inc_return(&key->u.gcmp.tx_pn);
 673
 674         pn[5] = pn64;
 675         pn[4] = pn64 >> 8;
 676         pn[3] = pn64 >> 16;
 677         pn[2] = pn64 >> 24;
 678         pn[1] = pn64 >> 32;
 679         pn[0] = pn64 >> 40;
 680
 681         gcmp_pn2hdr(pos, pn, key->conf.keyidx);
 682
 683         /* hwaccel - with software GCMP header */
 684         if (info->control.hw_key)
 685                 return 0;
 686
 687         pos += IEEE80211_GCMP_HDR_LEN;
 688         gcmp_special_blocks(skb, pn, j_0, aad);
 689         ieee80211_aes_gcm_encrypt(key->u.gcmp.tfm, j_0, aad, pos, len,
 690                                   skb_put(skb, IEEE80211_GCMP_MIC_LEN));
 691
 692         return 0;
 693 }
 694
 695 ieee80211_tx_result
 696 ieee80211_crypto_gcmp_encrypt(struct ieee80211_tx_data *tx)
 697 {
 698         struct sk_buff *skb;
 699
 700         ieee80211_tx_set_protected(tx);
 701
 702         skb_queue_walk(&tx->skbs, skb) {
 703                 if (gcmp_encrypt_skb(tx, skb) < 0)
 704                         return TX_DROP;
 705         }
 706
 707         return TX_CONTINUE;
 708 }
 709
 710 ieee80211_rx_result
 711 ieee80211_crypto_gcmp_decrypt(struct ieee80211_rx_data *rx)
 712 {
 713         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 714         int hdrlen;
 715         struct ieee80211_key *key = rx->key;
 716         struct sk_buff *skb = rx->skb;
 717         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 718         u8 pn[IEEE80211_GCMP_PN_LEN];
 719         int data_len;
 720         int queue;
 721
 722         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 723
 724         if (!ieee80211_is_data(hdr->frame_control) &&
 725             !ieee80211_is_robust_mgmt_frame(skb))
 726                 return RX_CONTINUE;
 727
 728         data_len = skb->len - hdrlen - IEEE80211_GCMP_HDR_LEN -
 729                    IEEE80211_GCMP_MIC_LEN;
 730         if (!rx->sta || data_len < 0)
 731                 return RX_DROP_UNUSABLE;
 732
 733         if (status->flag & RX_FLAG_DECRYPTED) {
 734                 if (!pskb_may_pull(rx->skb, hdrlen + IEEE80211_GCMP_HDR_LEN))
 735                         return RX_DROP_UNUSABLE;
 736         } else {
 737                 if (skb_linearize(rx->skb))
 738                         return RX_DROP_UNUSABLE;
 739         }
 740
 741         gcmp_hdr2pn(pn, skb->data + hdrlen);
 742
 743         queue = rx->security_idx;
 744
 745         if (memcmp(pn, key->u.gcmp.rx_pn[queue], IEEE80211_GCMP_PN_LEN) <= 0) {
 746                 key->u.gcmp.replays++;
 747                 return RX_DROP_UNUSABLE;
 748         }
 749
 750         if (!(status->flag & RX_FLAG_DECRYPTED)) {
 751                 u8 aad[2 * AES_BLOCK_SIZE];
 752                 u8 j_0[AES_BLOCK_SIZE];
 753                 /* hardware didn't decrypt/verify MIC */
 754                 gcmp_special_blocks(skb, pn, j_0, aad);
 755
 756                 if (ieee80211_aes_gcm_decrypt(
 757                             key->u.gcmp.tfm, j_0, aad,
 758                             skb->data + hdrlen + IEEE80211_GCMP_HDR_LEN,
 759                             data_len,
 760                             skb->data + skb->len - IEEE80211_GCMP_MIC_LEN))
 761                         return RX_DROP_UNUSABLE;
 762         }
 763
 764         memcpy(key->u.gcmp.rx_pn[queue], pn, IEEE80211_GCMP_PN_LEN);
 765
 766         /* Remove GCMP header and MIC */
 767         if (pskb_trim(skb, skb->len - IEEE80211_GCMP_MIC_LEN))
 768                 return RX_DROP_UNUSABLE;
 769         memmove(skb->data + IEEE80211_GCMP_HDR_LEN, skb->data, hdrlen);
 770         skb_pull(skb, IEEE80211_GCMP_HDR_LEN);
 771
 772         return RX_CONTINUE;
 773 }
 774
 775 static ieee80211_tx_result
 776 ieee80211_crypto_cs_encrypt(struct ieee80211_tx_data *tx,
 777                             struct sk_buff *skb)
 778 {
 779         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 780         struct ieee80211_key *key = tx->key;
 781         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 782         const struct ieee80211_cipher_scheme *cs = key->sta->cipher_scheme;
 783         int hdrlen;
 784         u8 *pos;
 785
 786         if (info->control.hw_key &&
 787             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 788                 /* hwaccel has no need for preallocated head room */
 789                 return TX_CONTINUE;
 790         }
 791
 792         if (unlikely(skb_headroom(skb) < cs->hdr_len &&
 793                      pskb_expand_head(skb, cs->hdr_len, 0, GFP_ATOMIC)))
 794                 return TX_DROP;
 795
 796         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 797
 798         pos = skb_push(skb, cs->hdr_len);
 799         memmove(pos, pos + cs->hdr_len, hdrlen);
 800
 801         return TX_CONTINUE;
 802 }
 803
 804 static inline int ieee80211_crypto_cs_pn_compare(u8 *pn1, u8 *pn2, int len)
 805 {
 806         int i;
 807
 808         /* pn is little endian */
 809         for (i = len - 1; i >= 0; i--) {
 810                 if (pn1[i] < pn2[i])
 811                         return -1;
 812                 else if (pn1[i] > pn2[i])
 813                         return 1;
 814         }
 815
 816         return 0;
 817 }
 818
 819 static ieee80211_rx_result
 820 ieee80211_crypto_cs_decrypt(struct ieee80211_rx_data *rx)
 821 {
 822         struct ieee80211_key *key = rx->key;
 823         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 824         const struct ieee80211_cipher_scheme *cs = NULL;
 825         int hdrlen = ieee80211_hdrlen(hdr->frame_control);
 826         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
 827         int data_len;
 828         u8 *rx_pn;
 829         u8 *skb_pn;
 830         u8 qos_tid;
 831
 832         if (!rx->sta || !rx->sta->cipher_scheme ||
 833             !(status->flag & RX_FLAG_DECRYPTED))
 834                 return RX_DROP_UNUSABLE;
 835
 836         if (!ieee80211_is_data(hdr->frame_control))
 837                 return RX_CONTINUE;
 838
 839         cs = rx->sta->cipher_scheme;
 840
 841         data_len = rx->skb->len - hdrlen - cs->hdr_len;
 842
 843         if (data_len < 0)
 844                 return RX_DROP_UNUSABLE;
 845
 846         if (ieee80211_is_data_qos(hdr->frame_control))
 847                 qos_tid = *ieee80211_get_qos_ctl(hdr) &
 848                                 IEEE80211_QOS_CTL_TID_MASK;
 849         else
 850                 qos_tid = 0;
 851
 852         if (skb_linearize(rx->skb))
 853                 return RX_DROP_UNUSABLE;
 854
 855         hdr = (struct ieee80211_hdr *)rx->skb->data;
 856
 857         rx_pn = key->u.gen.rx_pn[qos_tid];
 858         skb_pn = rx->skb->data + hdrlen + cs->pn_off;
 859
 860         if (ieee80211_crypto_cs_pn_compare(skb_pn, rx_pn, cs->pn_len) <= 0)
 861                 return RX_DROP_UNUSABLE;
 862
 863         memcpy(rx_pn, skb_pn, cs->pn_len);
 864
 865         /* remove security header and MIC */
 866         if (pskb_trim(rx->skb, rx->skb->len - cs->mic_len))
 867                 return RX_DROP_UNUSABLE;
 868
 869         memmove(rx->skb->data + cs->hdr_len, rx->skb->data, hdrlen);
 870         skb_pull(rx->skb, cs->hdr_len);
 871
 872         return RX_CONTINUE;
 873 }
 874
 875 static void bip_aad(struct sk_buff *skb, u8 *aad)
 876 {
 877         __le16 mask_fc;
 878         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 879
 880         /* BIP AAD: FC(masked) || A1 || A2 || A3 */
 881
 882         /* FC type/subtype */
 883         /* Mask FC Retry, PwrMgt, MoreData flags to zero */
 884         mask_fc = hdr->frame_control;
 885         mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM |
 886                                 IEEE80211_FCTL_MOREDATA);
 887         put_unaligned(mask_fc, (__le16 *) &aad[0]);
 888         /* A1 || A2 || A3 */
 889         memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN);
 890 }
 891
 892
 893 static inline void bip_ipn_set64(u8 *d, u64 pn)
 894 {
 895         *d++ = pn;
 896         *d++ = pn >> 8;
 897         *d++ = pn >> 16;
 898         *d++ = pn >> 24;
 899         *d++ = pn >> 32;
 900         *d = pn >> 40;
 901 }
 902
 903 static inline void bip_ipn_swap(u8 *d, const u8 *s)
 904 {
 905         *d++ = s[5];
 906         *d++ = s[4];
 907         *d++ = s[3];
 908         *d++ = s[2];
 909         *d++ = s[1];
 910         *d = s[0];
 911 }
 912
 913
 914 ieee80211_tx_result
 915 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 916 {
 917         struct sk_buff *skb;
 918         struct ieee80211_tx_info *info;
 919         struct ieee80211_key *key = tx->key;
 920         struct ieee80211_mmie *mmie;
 921         u8 aad[20];
 922         u64 pn64;
 923
 924         if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
 925                 return TX_DROP;
 926
 927         skb = skb_peek(&tx->skbs);
 928
 929         info = IEEE80211_SKB_CB(skb);
 930
 931         if (info->control.hw_key)
 932                 return TX_CONTINUE;
 933
 934         if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 935                 return TX_DROP;
 936
 937         mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
 938         mmie->element_id = WLAN_EID_MMIE;
 939         mmie->length = sizeof(*mmie) - 2;
 940         mmie->key_id = cpu_to_le16(key->conf.keyidx);
 941
 942         /* PN = PN + 1 */
 943         pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
 944
 945         bip_ipn_set64(mmie->sequence_number, pn64);
 946
 947         bip_aad(skb, aad);
 948
 949         /*
 950          * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
 951          */
 952         ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 953                            skb->data + 24, skb->len - 24, mmie->mic);
 954
 955         return TX_CONTINUE;
 956 }
 957
 958 ieee80211_tx_result
 959 ieee80211_crypto_aes_cmac_256_encrypt(struct ieee80211_tx_data *tx)
 960 {
 961         struct sk_buff *skb;
 962         struct ieee80211_tx_info *info;
 963         struct ieee80211_key *key = tx->key;
 964         struct ieee80211_mmie_16 *mmie;
 965         u8 aad[20];
 966         u64 pn64;
 967
 968         if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
 969                 return TX_DROP;
 970
 971         skb = skb_peek(&tx->skbs);
 972
 973         info = IEEE80211_SKB_CB(skb);
 974
 975         if (info->control.hw_key)
 976                 return TX_CONTINUE;
 977
 978         if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 979                 return TX_DROP;
 980
 981         mmie = (struct ieee80211_mmie_16 *)skb_put(skb, sizeof(*mmie));
 982         mmie->element_id = WLAN_EID_MMIE;
 983         mmie->length = sizeof(*mmie) - 2;
 984         mmie->key_id = cpu_to_le16(key->conf.keyidx);
 985
 986         /* PN = PN + 1 */
 987         pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
 988
 989         bip_ipn_set64(mmie->sequence_number, pn64);
 990
 991         bip_aad(skb, aad);
 992
 993         /* MIC = AES-256-CMAC(IGTK, AAD || Management Frame Body || MMIE, 128)
 994          */
 995         ieee80211_aes_cmac_256(key->u.aes_cmac.tfm, aad,
 996                                skb->data + 24, skb->len - 24, mmie->mic);
 997
 998         return TX_CONTINUE;
 999 }
1000
1001 ieee80211_rx_result
1002 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
1003 {
1004         struct sk_buff *skb = rx->skb;
1005         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
1006         struct ieee80211_key *key = rx->key;
1007         struct ieee80211_mmie *mmie;
1008         u8 aad[20], mic[8], ipn[6];
1009         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1010
1011         if (!ieee80211_is_mgmt(hdr->frame_control))
1012                 return RX_CONTINUE;
1013
1014         /* management frames are already linear */
1015
1016         if (skb->len < 24 + sizeof(*mmie))
1017                 return RX_DROP_UNUSABLE;
1018
1019         mmie = (struct ieee80211_mmie *)
1020                 (skb->data + skb->len - sizeof(*mmie));
1021         if (mmie->element_id != WLAN_EID_MMIE ||
1022             mmie->length != sizeof(*mmie) - 2)
1023                 return RX_DROP_UNUSABLE; /* Invalid MMIE */
1024
1025         bip_ipn_swap(ipn, mmie->sequence_number);
1026
1027         if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
1028                 key->u.aes_cmac.replays++;
1029                 return RX_DROP_UNUSABLE;
1030         }
1031
1032         if (!(status->flag & RX_FLAG_DECRYPTED)) {
1033                 /* hardware didn't decrypt/verify MIC */
1034                 bip_aad(skb, aad);
1035                 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
1036                                    skb->data + 24, skb->len - 24, mic);
1037                 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
1038                         key->u.aes_cmac.icverrors++;
1039                         return RX_DROP_UNUSABLE;
1040                 }
1041         }
1042
1043         memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
1044
1045         /* Remove MMIE */
1046         skb_trim(skb, skb->len - sizeof(*mmie));
1047
1048         return RX_CONTINUE;
1049 }
1050
1051 ieee80211_rx_result
1052 ieee80211_crypto_aes_cmac_256_decrypt(struct ieee80211_rx_data *rx)
1053 {
1054         struct sk_buff *skb = rx->skb;
1055         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
1056         struct ieee80211_key *key = rx->key;
1057         struct ieee80211_mmie_16 *mmie;
1058         u8 aad[20], mic[16], ipn[6];
1059         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1060
1061         if (!ieee80211_is_mgmt(hdr->frame_control))
1062                 return RX_CONTINUE;
1063
1064         /* management frames are already linear */
1065
1066         if (skb->len < 24 + sizeof(*mmie))
1067                 return RX_DROP_UNUSABLE;
1068
1069         mmie = (struct ieee80211_mmie_16 *)
1070                 (skb->data + skb->len - sizeof(*mmie));
1071         if (mmie->element_id != WLAN_EID_MMIE ||
1072             mmie->length != sizeof(*mmie) - 2)
1073                 return RX_DROP_UNUSABLE; /* Invalid MMIE */
1074
1075         bip_ipn_swap(ipn, mmie->sequence_number);
1076
1077         if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
1078                 key->u.aes_cmac.replays++;
1079                 return RX_DROP_UNUSABLE;
1080         }
1081
1082         if (!(status->flag & RX_FLAG_DECRYPTED)) {
1083                 /* hardware didn't decrypt/verify MIC */
1084                 bip_aad(skb, aad);
1085                 ieee80211_aes_cmac_256(key->u.aes_cmac.tfm, aad,
1086                                        skb->data + 24, skb->len - 24, mic);
1087                 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
1088                         key->u.aes_cmac.icverrors++;
1089                         return RX_DROP_UNUSABLE;
1090                 }
1091         }
1092
1093         memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
1094
1095         /* Remove MMIE */
1096         skb_trim(skb, skb->len - sizeof(*mmie));
1097
1098         return RX_CONTINUE;
1099 }
1100
1101 ieee80211_tx_result
1102 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
1103 {
1104         struct sk_buff *skb;
1105         struct ieee80211_tx_info *info = NULL;
1106         ieee80211_tx_result res;
1107
1108         skb_queue_walk(&tx->skbs, skb) {
1109                 info  = IEEE80211_SKB_CB(skb);
1110
1111                 /* handle hw-only algorithm */
1112                 if (!info->control.hw_key)
1113                         return TX_DROP;
1114
1115                 if (tx->key->sta->cipher_scheme) {
1116                         res = ieee80211_crypto_cs_encrypt(tx, skb);
1117                         if (res != TX_CONTINUE)
1118                                 return res;
1119                 }
1120         }
1121
1122         ieee80211_tx_set_protected(tx);
1123
1124         return TX_CONTINUE;
1125 }
1126
1127 ieee80211_rx_result
1128 ieee80211_crypto_hw_decrypt(struct ieee80211_rx_data *rx)
1129 {
1130         if (rx->sta && rx->sta->cipher_scheme)
1131                 return ieee80211_crypto_cs_decrypt(rx);
1132
1133         return RX_DROP_UNUSABLE;
1134 }