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