package/network/services/hostapd/patches/008-Prevent-installation-of-an-all-zero-TK.patch

   1 From: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
   2 Date: Fri, 29 Sep 2017 04:22:51 +0200
   3 Subject: [PATCH] Prevent installation of an all-zero TK
   4
   5 Properly track whether a PTK has already been installed to the driver
   6 and the TK part cleared from memory. This prevents an attacker from
   7 trying to trick the client into installing an all-zero TK.
   8
   9 This fixes the earlier fix in commit
  10 ad00d64e7d8827b3cebd665a0ceb08adabf15e1e ('Fix TK configuration to the
  11 driver in EAPOL-Key 3/4 retry case') which did not take into account
  12 possibility of an extra message 1/4 showing up between retries of
  13 message 3/4.
  14
  15 Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
  16 ---
  17
  18 --- a/src/common/wpa_common.h
  19 +++ b/src/common/wpa_common.h
  20 @@ -205,6 +205,7 @@ struct wpa_ptk {
  21         size_t kck_len;
  22         size_t kek_len;
  23         size_t tk_len;
  24 +       int installed; /* 1 if key has already been installed to driver */
  25  };
  26
  27  struct wpa_gtk {
  28 --- a/src/rsn_supp/wpa.c
  29 +++ b/src/rsn_supp/wpa.c
  30 @@ -581,7 +581,6 @@ static void wpa_supplicant_process_1_of_
  31                 os_memset(buf, 0, sizeof(buf));
  32         }
  33         sm->tptk_set = 1;
  34 -       sm->tk_to_set = 1;
  35
  36         kde = sm->assoc_wpa_ie;
  37         kde_len = sm->assoc_wpa_ie_len;
  38 @@ -686,7 +685,7 @@ static int wpa_supplicant_install_ptk(st
  39         enum wpa_alg alg;
  40         const u8 *key_rsc;
  41
  42 -       if (!sm->tk_to_set) {
  43 +       if (sm->ptk.installed) {
  44                 wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG,
  45                         "WPA: Do not re-install same PTK to the driver");
  46                 return 0;
  47 @@ -730,7 +729,7 @@ static int wpa_supplicant_install_ptk(st
  48
  49         /* TK is not needed anymore in supplicant */
  50         os_memset(sm->ptk.tk, 0, WPA_TK_MAX_LEN);
  51 -       sm->tk_to_set = 0;
  52 +       sm->ptk.installed = 1;
  53
  54         if (sm->wpa_ptk_rekey) {
  55                 eloop_cancel_timeout(wpa_sm_rekey_ptk, sm, NULL);
  56 --- a/src/rsn_supp/wpa_i.h
  57 +++ b/src/rsn_supp/wpa_i.h
  58 @@ -24,7 +24,6 @@ struct wpa_sm {
  59         struct wpa_ptk ptk, tptk;
  60         int ptk_set, tptk_set;
  61         unsigned int msg_3_of_4_ok:1;
  62 -       unsigned int tk_to_set:1;
  63         u8 snonce[WPA_NONCE_LEN];
  64         u8 anonce[WPA_NONCE_LEN]; /* ANonce from the last 1/4 msg */
  65         int renew_snonce;