src/patches/wpa_supplicant/0004-Prevent-installation-of-an-all-zero-TK.patch

   1 From 327b6d780f2667e99e9b74d4c064531c0208b22b Mon Sep 17 00:00:00 2001
   2 From: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
   3 Date: Fri, 29 Sep 2017 04:22:51 +0200
   4 Subject: [PATCH 4/8] Prevent installation of an all-zero TK
   5
   6 Properly track whether a PTK has already been installed to the driver
   7 and the TK part cleared from memory. This prevents an attacker from
   8 trying to trick the client into installing an all-zero TK.
   9
  10 This fixes the earlier fix in commit
  11 ad00d64e7d8827b3cebd665a0ceb08adabf15e1e ('Fix TK configuration to the
  12 driver in EAPOL-Key 3/4 retry case') which did not take into account
  13 possibility of an extra message 1/4 showing up between retries of
  14 message 3/4.
  15
  16 Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
  17 ---
  18  src/common/wpa_common.h | 1 +
  19  src/rsn_supp/wpa.c      | 6 +++---
  20  src/rsn_supp/wpa_i.h    | 1 -
  21  3 files changed, 4 insertions(+), 4 deletions(-)
  22
  23 diff --git a/src/common/wpa_common.h b/src/common/wpa_common.h
  24 index 0872b12..8411686 100644
  25 --- a/src/common/wpa_common.h
  26 +++ b/src/common/wpa_common.h
  27 @@ -219,6 +219,7 @@ struct wpa_ptk {
  28         size_t kck_len;
  29         size_t kek_len;
  30         size_t tk_len;
  31 +       int installed; /* 1 if key has already been installed to driver */
  32  };
  33
  34  struct wpa_gtk {
  35 diff --git a/src/rsn_supp/wpa.c b/src/rsn_supp/wpa.c
  36 index 3c8871d..cf9bf1c 100644
  37 --- a/src/rsn_supp/wpa.c
  38 +++ b/src/rsn_supp/wpa.c
  39 @@ -594,7 +594,6 @@ static void wpa_supplicant_process_1_of_4(struct wpa_sm *sm,
  40                 os_memset(buf, 0, sizeof(buf));
  41         }
  42         sm->tptk_set = 1;
  43 -       sm->tk_to_set = 1;
  44
  45         kde = sm->assoc_wpa_ie;
  46         kde_len = sm->assoc_wpa_ie_len;
  47 @@ -701,7 +700,7 @@ static int wpa_supplicant_install_ptk(struct wpa_sm *sm,
  48         enum wpa_alg alg;
  49         const u8 *key_rsc;
  50
  51 -       if (!sm->tk_to_set) {
  52 +       if (sm->ptk.installed) {
  53                 wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG,
  54                         "WPA: Do not re-install same PTK to the driver");
  55                 return 0;
  56 @@ -745,7 +744,7 @@ static int wpa_supplicant_install_ptk(struct wpa_sm *sm,
  57
  58         /* TK is not needed anymore in supplicant */
  59         os_memset(sm->ptk.tk, 0, WPA_TK_MAX_LEN);
  60 -       sm->tk_to_set = 0;
  61 +       sm->ptk.installed = 1;
  62
  63         if (sm->wpa_ptk_rekey) {
  64                 eloop_cancel_timeout(wpa_sm_rekey_ptk, sm, NULL);
  65 @@ -4183,6 +4182,7 @@ int fils_process_assoc_resp(struct wpa_sm *sm, const u8 *resp, size_t len)
  66          * takes care of association frame encryption/decryption. */
  67         /* TK is not needed anymore in supplicant */
  68         os_memset(sm->ptk.tk, 0, WPA_TK_MAX_LEN);
  69 +       sm->ptk.installed = 1;
  70
  71         /* FILS HLP Container */
  72         fils_process_hlp_container(sm, ie_start, end - ie_start);
  73 diff --git a/src/rsn_supp/wpa_i.h b/src/rsn_supp/wpa_i.h
  74 index 156e6cb..3b42245 100644
  75 --- a/src/rsn_supp/wpa_i.h
  76 +++ b/src/rsn_supp/wpa_i.h
  77 @@ -24,7 +24,6 @@ struct wpa_sm {
  78         struct wpa_ptk ptk, tptk;
  79         int ptk_set, tptk_set;
  80         unsigned int msg_3_of_4_ok:1;
  81 -       unsigned int tk_to_set:1;
  82         u8 snonce[WPA_NONCE_LEN];
  83         u8 anonce[WPA_NONCE_LEN]; /* ANonce from the last 1/4 msg */
  84         int renew_snonce;
  85 --
  86 2.7.4
  87