package/network/services/hostapd/patches/009-Clear-PMK-length-and-check-for-this-when-deriving-PT.patch

   1 From b488a12948751f57871f09baa345e59b23959a41 Mon Sep 17 00:00:00 2001
   2 From: Jouni Malinen <j@w1.fi>
   3 Date: Sun, 8 Oct 2017 13:18:02 +0300
   4 Subject: [PATCH] Clear PMK length and check for this when deriving PTK
   5
   6 Instead of setting the default PMK length for the cleared PMK, set the
   7 length to 0 and explicitly check for this when deriving PTK to avoid
   8 unexpected key derivation with an all-zeroes key should it be possible
   9 to somehow trigger PTK derivation to happen before PMK derivation.
  10
  11 Signed-off-by: Jouni Malinen <j@w1.fi>
  12 ---
  13  src/common/wpa_common.c | 5 +++++
  14  src/rsn_supp/wpa.c      | 7 ++++---
  15  2 files changed, 9 insertions(+), 3 deletions(-)
  16
  17 --- a/src/common/wpa_common.c
  18 +++ b/src/common/wpa_common.c
  19 @@ -225,6 +225,11 @@ int wpa_pmk_to_ptk(const u8 *pmk, size_t
  20         u8 tmp[WPA_KCK_MAX_LEN + WPA_KEK_MAX_LEN + WPA_TK_MAX_LEN];
  21         size_t ptk_len;
  22
  23 +       if (pmk_len == 0) {
  24 +               wpa_printf(MSG_ERROR, "WPA: No PMK set for PT derivation");
  25 +               return -1;
  26 +       }
  27 +
  28         if (os_memcmp(addr1, addr2, ETH_ALEN) < 0) {
  29                 os_memcpy(data, addr1, ETH_ALEN);
  30                 os_memcpy(data + ETH_ALEN, addr2, ETH_ALEN);
  31 --- a/src/rsn_supp/wpa.c
  32 +++ b/src/rsn_supp/wpa.c
  33 @@ -584,7 +584,8 @@ static void wpa_supplicant_process_1_of_
  34         /* Calculate PTK which will be stored as a temporary PTK until it has
  35          * been verified when processing message 3/4. */
  36         ptk = &sm->tptk;
  37 -       wpa_derive_ptk(sm, src_addr, key, ptk);
  38 +       if (wpa_derive_ptk(sm, src_addr, key, ptk) < 0)
  39 +               goto failed;
  40         if (sm->pairwise_cipher == WPA_CIPHER_TKIP) {
  41                 u8 buf[8];
  42                 /* Supplicant: swap tx/rx Mic keys */
  43 @@ -2705,8 +2706,8 @@ void wpa_sm_set_pmk_from_pmksa(struct wp
  44                 sm->pmk_len = sm->cur_pmksa->pmk_len;
  45                 os_memcpy(sm->pmk, sm->cur_pmksa->pmk, sm->pmk_len);
  46         } else {
  47 -               sm->pmk_len = PMK_LEN;
  48 -               os_memset(sm->pmk, 0, PMK_LEN);
  49 +               sm->pmk_len = 0;
  50 +               os_memset(sm->pmk, 0, PMK_LEN_MAX);
  51         }
  52  }
  53