wlantest/bip.c

   1 /*
   2  * BIP
   3  * Copyright (c) 2010-2012, Jouni Malinen <j@w1.fi>
   4  *
   5  * This software may be distributed under the terms of the BSD license.
   6  * See README for more details.
   7  */
   8
   9 #include "utils/includes.h"
  10
  11 #include "utils/common.h"
  12 #include "common/ieee802_11_defs.h"
  13 #include "crypto/aes_wrap.h"
  14 #include "wlantest.h"
  15
  16
  17 u8 * bip_protect(const u8 *igtk, u8 *frame, size_t len, u8 *ipn, int keyid,
  18                  size_t *prot_len)
  19 {
  20         u8 *prot, *pos, *buf;
  21         u8 mic[16];
  22         u16 fc;
  23         struct ieee80211_hdr *hdr;
  24         size_t plen;
  25
  26         plen = len + 18;
  27         prot = os_malloc(plen);
  28         if (prot == NULL)
  29                 return NULL;
  30         os_memcpy(prot, frame, len);
  31         pos = prot + len;
  32         *pos++ = WLAN_EID_MMIE;
  33         *pos++ = 16;
  34         WPA_PUT_LE16(pos, keyid);
  35         pos += 2;
  36         os_memcpy(pos, ipn, 6);
  37         pos += 6;
  38         os_memset(pos, 0, 8); /* MIC */
  39
  40         buf = os_malloc(plen + 20 - 24);
  41         if (buf == NULL) {
  42                 os_free(prot);
  43                 return NULL;
  44         }
  45
  46         /* BIP AAD: FC(masked) A1 A2 A3 */
  47         hdr = (struct ieee80211_hdr *) frame;
  48         fc = le_to_host16(hdr->frame_control);
  49         fc &= ~(WLAN_FC_RETRY | WLAN_FC_PWRMGT | WLAN_FC_MOREDATA);
  50         WPA_PUT_LE16(buf, fc);
  51         os_memcpy(buf + 2, hdr->addr1, 3 * ETH_ALEN);
  52         os_memcpy(buf + 20, prot + 24, plen - 24);
  53         wpa_hexdump(MSG_MSGDUMP, "BIP: AAD|Body(masked)", buf, plen + 20 - 24);
  54         /* MIC = L(AES-128-CMAC(AAD || Frame Body(masked)), 0, 64) */
  55         if (omac1_aes_128(igtk, buf, plen + 20 - 24, mic) < 0) {
  56                 os_free(prot);
  57                 os_free(buf);
  58                 return NULL;
  59         }
  60         os_free(buf);
  61
  62         os_memcpy(pos, mic, 8);
  63         wpa_hexdump(MSG_DEBUG, "BIP MMIE MIC", pos, 8);
  64
  65         *prot_len = plen;
  66         return prot;
  67 }