linux/net/mac80211/wpa.c
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   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
  27ieee80211_tx_result
  28ieee80211_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 += TKIP_ICV_LEN;
  66
  67        if (WARN_ON(skb_tailroom(skb) < tail ||
  68                    skb_headroom(skb) < 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
  81ieee80211_rx_result
  82ieee80211_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;
 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
 156update_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
 163mic_fail:
 164        /*
 165         * In some cases the key can be unset - e.g. a multicast packet, in
 166         * a driver that supports HW encryption. Send up the key idx only if
 167         * the key is set.
 168         */
 169        mac80211_ev_michael_mic_failure(rx->sdata,
 170                                        rx->key ? rx->key->conf.keyidx : -1,
 171                                        (void *) skb->data, NULL, GFP_ATOMIC);
 172        return RX_DROP_UNUSABLE;
 173}
 174
 175
 176static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 177{
 178        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 179        struct ieee80211_key *key = tx->key;
 180        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 181        unsigned long flags;
 182        unsigned int hdrlen;
 183        int len, tail;
 184        u8 *pos;
 185
 186        if (info->control.hw_key &&
 187            !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 188            !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 189                /* hwaccel - with no need for software-generated IV */
 190                return 0;
 191        }
 192
 193        hdrlen = ieee80211_hdrlen(hdr->frame_control);
 194        len = skb->len - hdrlen;
 195
 196        if (info->control.hw_key)
 197                tail = 0;
 198        else
 199                tail = TKIP_ICV_LEN;
 200
 201        if (WARN_ON(skb_tailroom(skb) < tail ||
 202                    skb_headroom(skb) < TKIP_IV_LEN))
 203                return -1;
 204
 205        pos = skb_push(skb, TKIP_IV_LEN);
 206        memmove(pos, pos + TKIP_IV_LEN, hdrlen);
 207        skb_set_network_header(skb, skb_network_offset(skb) + TKIP_IV_LEN);
 208        pos += hdrlen;
 209
 210        /* the HW only needs room for the IV, but not the actual IV */
 211        if (info->control.hw_key &&
 212            (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
 213                return 0;
 214
 215        /* Increase IV for the frame */
 216        spin_lock_irqsave(&key->u.tkip.txlock, flags);
 217        key->u.tkip.tx.iv16++;
 218        if (key->u.tkip.tx.iv16 == 0)
 219                key->u.tkip.tx.iv32++;
 220        pos = ieee80211_tkip_add_iv(pos, key);
 221        spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
 222
 223        /* hwaccel - with software IV */
 224        if (info->control.hw_key)
 225                return 0;
 226
 227        /* Add room for ICV */
 228        skb_put(skb, TKIP_ICV_LEN);
 229
 230        return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
 231                                           key, skb, pos, len);
 232}
 233
 234
 235ieee80211_tx_result
 236ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
 237{
 238        struct sk_buff *skb;
 239
 240        ieee80211_tx_set_protected(tx);
 241
 242        skb_queue_walk(&tx->skbs, skb) {
 243                if (tkip_encrypt_skb(tx, skb) < 0)
 244                        return TX_DROP;
 245        }
 246
 247        return TX_CONTINUE;
 248}
 249
 250
 251ieee80211_rx_result
 252ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
 253{
 254        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
 255        int hdrlen, res, hwaccel = 0;
 256        struct ieee80211_key *key = rx->key;
 257        struct sk_buff *skb = rx->skb;
 258        struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 259
 260        hdrlen = ieee80211_hdrlen(hdr->frame_control);
 261
 262        if (!ieee80211_is_data(hdr->frame_control))
 263                return RX_CONTINUE;
 264
 265        if (!rx->sta || skb->len - hdrlen < 12)
 266                return RX_DROP_UNUSABLE;
 267
 268        /* it may be possible to optimize this a bit more */
 269        if (skb_linearize(rx->skb))
 270                return RX_DROP_UNUSABLE;
 271        hdr = (void *)skb->data;
 272
 273        /*
 274         * Let TKIP code verify IV, but skip decryption.
 275         * In the case where hardware checks the IV as well,
 276         * we don't even get here, see ieee80211_rx_h_decrypt()
 277         */
 278        if (status->flag & RX_FLAG_DECRYPTED)
 279                hwaccel = 1;
 280
 281        res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
 282                                          key, skb->data + hdrlen,
 283                                          skb->len - hdrlen, rx->sta->sta.addr,
 284                                          hdr->addr1, hwaccel, rx->security_idx,
 285                                          &rx->tkip_iv32,
 286                                          &rx->tkip_iv16);
 287        if (res != TKIP_DECRYPT_OK)
 288                return RX_DROP_UNUSABLE;
 289
 290        /* Trim ICV */
 291        skb_trim(skb, skb->len - TKIP_ICV_LEN);
 292
 293        /* Remove IV */
 294        memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
 295        skb_pull(skb, TKIP_IV_LEN);
 296
 297        return RX_CONTINUE;
 298}
 299
 300
 301static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
 302                                int encrypted)
 303{
 304        __le16 mask_fc;
 305        int a4_included, mgmt;
 306        u8 qos_tid;
 307        u8 *b_0, *aad;
 308        u16 data_len, len_a;
 309        unsigned int hdrlen;
 310        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 311
 312        memset(scratch, 0, 6 * AES_BLOCK_SIZE);
 313
 314        b_0 = scratch + 3 * AES_BLOCK_SIZE;
 315        aad = scratch + 4 * AES_BLOCK_SIZE;
 316
 317        /*
 318         * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
 319         * Retry, PwrMgt, MoreData; set Protected
 320         */
 321        mgmt = ieee80211_is_mgmt(hdr->frame_control);
 322        mask_fc = hdr->frame_control;
 323        mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
 324                                IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
 325        if (!mgmt)
 326                mask_fc &= ~cpu_to_le16(0x0070);
 327        mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 328
 329        hdrlen = ieee80211_hdrlen(hdr->frame_control);
 330        len_a = hdrlen - 2;
 331        a4_included = ieee80211_has_a4(hdr->frame_control);
 332
 333        if (ieee80211_is_data_qos(hdr->frame_control))
 334                qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 335        else
 336                qos_tid = 0;
 337
 338        data_len = skb->len - hdrlen - CCMP_HDR_LEN;
 339        if (encrypted)
 340                data_len -= CCMP_MIC_LEN;
 341
 342        /* First block, b_0 */
 343        b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
 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, CCMP_PN_LEN);
 350        /* l(m) */
 351        put_unaligned_be16(data_len, &b_0[14]);
 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
 374static 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
 387static 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
 398static 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 scratch[6 * AES_BLOCK_SIZE];
 408
 409        if (info->control.hw_key &&
 410            !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
 411            !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
 412                /*
 413                 * hwaccel has no need for preallocated room for CCMP
 414                 * header or MIC fields
 415                 */
 416                return 0;
 417        }
 418
 419        hdrlen = ieee80211_hdrlen(hdr->frame_control);
 420        len = skb->len - hdrlen;
 421
 422        if (info->control.hw_key)
 423                tail = 0;
 424        else
 425                tail = CCMP_MIC_LEN;
 426
 427        if (WARN_ON(skb_tailroom(skb) < tail ||
 428                    skb_headroom(skb) < CCMP_HDR_LEN))
 429                return -1;
 430
 431        pos = skb_push(skb, CCMP_HDR_LEN);
 432        memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
 433        skb_set_network_header(skb, skb_network_offset(skb) + 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 += CCMP_HDR_LEN;
 459        ccmp_special_blocks(skb, pn, scratch, 0);
 460        ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
 461                                  pos, skb_put(skb, CCMP_MIC_LEN));
 462
 463        return 0;
 464}
 465
 466
 467ieee80211_tx_result
 468ieee80211_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
 483ieee80211_rx_result
 484ieee80211_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[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 - CCMP_HDR_LEN - CCMP_MIC_LEN;
 502        if (!rx->sta || data_len < 0)
 503                return RX_DROP_UNUSABLE;
 504
 505        if (status->flag & RX_FLAG_DECRYPTED) {
 506                if (!pskb_may_pull(rx->skb, hdrlen + CCMP_HDR_LEN))
 507                        return RX_DROP_UNUSABLE;
 508        } else {
 509                if (skb_linearize(rx->skb))
 510                        return RX_DROP_UNUSABLE;
 511        }
 512
 513        ccmp_hdr2pn(pn, skb->data + hdrlen);
 514
 515        queue = rx->security_idx;
 516
 517        if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
 518                key->u.ccmp.replays++;
 519                return RX_DROP_UNUSABLE;
 520        }
 521
 522        if (!(status->flag & RX_FLAG_DECRYPTED)) {
 523                u8 scratch[6 * AES_BLOCK_SIZE];
 524                /* hardware didn't decrypt/verify MIC */
 525                ccmp_special_blocks(skb, pn, scratch, 1);
 526
 527                if (ieee80211_aes_ccm_decrypt(
 528                            key->u.ccmp.tfm, scratch,
 529                            skb->data + hdrlen + CCMP_HDR_LEN, data_len,
 530                            skb->data + skb->len - CCMP_MIC_LEN,
 531                            skb->data + hdrlen + CCMP_HDR_LEN))
 532                        return RX_DROP_UNUSABLE;
 533        }
 534
 535        memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
 536
 537        /* Remove CCMP header and MIC */
 538        if (pskb_trim(skb, skb->len - CCMP_MIC_LEN))
 539                return RX_DROP_UNUSABLE;
 540        memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
 541        skb_pull(skb, CCMP_HDR_LEN);
 542
 543        return RX_CONTINUE;
 544}
 545
 546
 547static void bip_aad(struct sk_buff *skb, u8 *aad)
 548{
 549        __le16 mask_fc;
 550        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 551
 552        /* BIP AAD: FC(masked) || A1 || A2 || A3 */
 553
 554        /* FC type/subtype */
 555        /* Mask FC Retry, PwrMgt, MoreData flags to zero */
 556        mask_fc = hdr->frame_control;
 557        mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM |
 558                                IEEE80211_FCTL_MOREDATA);
 559        put_unaligned(mask_fc, (__le16 *) &aad[0]);
 560        /* A1 || A2 || A3 */
 561        memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN);
 562}
 563
 564
 565static inline void bip_ipn_set64(u8 *d, u64 pn)
 566{
 567        *d++ = pn;
 568        *d++ = pn >> 8;
 569        *d++ = pn >> 16;
 570        *d++ = pn >> 24;
 571        *d++ = pn >> 32;
 572        *d = pn >> 40;
 573}
 574
 575static inline void bip_ipn_swap(u8 *d, const u8 *s)
 576{
 577        *d++ = s[5];
 578        *d++ = s[4];
 579        *d++ = s[3];
 580        *d++ = s[2];
 581        *d++ = s[1];
 582        *d = s[0];
 583}
 584
 585
 586ieee80211_tx_result
 587ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 588{
 589        struct sk_buff *skb;
 590        struct ieee80211_tx_info *info;
 591        struct ieee80211_key *key = tx->key;
 592        struct ieee80211_mmie *mmie;
 593        u8 aad[20];
 594        u64 pn64;
 595
 596        if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
 597                return TX_DROP;
 598
 599        skb = skb_peek(&tx->skbs);
 600
 601        info = IEEE80211_SKB_CB(skb);
 602
 603        if (info->control.hw_key)
 604                return TX_CONTINUE;
 605
 606        if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 607                return TX_DROP;
 608
 609        mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
 610        mmie->element_id = WLAN_EID_MMIE;
 611        mmie->length = sizeof(*mmie) - 2;
 612        mmie->key_id = cpu_to_le16(key->conf.keyidx);
 613
 614        /* PN = PN + 1 */
 615        pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
 616
 617        bip_ipn_set64(mmie->sequence_number, pn64);
 618
 619        bip_aad(skb, aad);
 620
 621        /*
 622         * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
 623         */
 624        ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 625                           skb->data + 24, skb->len - 24, mmie->mic);
 626
 627        return TX_CONTINUE;
 628}
 629
 630
 631ieee80211_rx_result
 632ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 633{
 634        struct sk_buff *skb = rx->skb;
 635        struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 636        struct ieee80211_key *key = rx->key;
 637        struct ieee80211_mmie *mmie;
 638        u8 aad[20], mic[8], ipn[6];
 639        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 640
 641        if (!ieee80211_is_mgmt(hdr->frame_control))
 642                return RX_CONTINUE;
 643
 644        /* management frames are already linear */
 645
 646        if (skb->len < 24 + sizeof(*mmie))
 647                return RX_DROP_UNUSABLE;
 648
 649        mmie = (struct ieee80211_mmie *)
 650                (skb->data + skb->len - sizeof(*mmie));
 651        if (mmie->element_id != WLAN_EID_MMIE ||
 652            mmie->length != sizeof(*mmie) - 2)
 653                return RX_DROP_UNUSABLE; /* Invalid MMIE */
 654
 655        bip_ipn_swap(ipn, mmie->sequence_number);
 656
 657        if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
 658                key->u.aes_cmac.replays++;
 659                return RX_DROP_UNUSABLE;
 660        }
 661
 662        if (!(status->flag & RX_FLAG_DECRYPTED)) {
 663                /* hardware didn't decrypt/verify MIC */
 664                bip_aad(skb, aad);
 665                ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 666                                   skb->data + 24, skb->len - 24, mic);
 667                if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
 668                        key->u.aes_cmac.icverrors++;
 669                        return RX_DROP_UNUSABLE;
 670                }
 671        }
 672
 673        memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
 674
 675        /* Remove MMIE */
 676        skb_trim(skb, skb->len - sizeof(*mmie));
 677
 678        return RX_CONTINUE;
 679}
 680
 681ieee80211_tx_result
 682ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
 683{
 684        struct sk_buff *skb;
 685        struct ieee80211_tx_info *info = NULL;
 686
 687        skb_queue_walk(&tx->skbs, skb) {
 688                info  = IEEE80211_SKB_CB(skb);
 689
 690                /* handle hw-only algorithm */
 691                if (!info->control.hw_key)
 692                        return TX_DROP;
 693        }
 694
 695        ieee80211_tx_set_protected(tx);
 696
 697        return TX_CONTINUE;
 698}
 699
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