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From a6ea665300919d6a3af22b1f4237203647fda93a Mon Sep 17 00:00:00 2001
From: Jouni Malinen <j@w1.fi>
Date: Tue, 17 Oct 2017 00:01:11 +0300
Subject: [PATCH] Additional consistentcy checks for PTK component lengths
Verify that TK, KCK, and KEK lengths are set to consistent values within
struct wpa_ptk before using them in supplicant. This is an additional
layer of protection against unexpected states.
Signed-off-by: Jouni Malinen <j@w1.fi>
---
src/common/wpa_common.c | 6 ++++++
src/rsn_supp/wpa.c | 26 ++++++++++++++++++++------
2 files changed, 26 insertions(+), 6 deletions(-)
--- a/src/common/wpa_common.c
+++ b/src/common/wpa_common.c
@@ -93,6 +93,12 @@ int wpa_eapol_key_mic(const u8 *key, siz
{
u8 hash[SHA384_MAC_LEN];
+ if (key_len == 0) {
+ wpa_printf(MSG_DEBUG,
+ "WPA: KCK not set - cannot calculate MIC");
+ return -1;
+ }
+
switch (ver) {
#ifndef CONFIG_FIPS
case WPA_KEY_INFO_TYPE_HMAC_MD5_RC4:
--- a/src/rsn_supp/wpa.c
+++ b/src/rsn_supp/wpa.c
@@ -710,6 +710,11 @@ static int wpa_supplicant_install_ptk(st
alg = wpa_cipher_to_alg(sm->pairwise_cipher);
keylen = wpa_cipher_key_len(sm->pairwise_cipher);
+ if (keylen <= 0 || (unsigned int) keylen != sm->ptk.tk_len) {
+ wpa_printf(MSG_DEBUG, "WPA: TK length mismatch: %d != %lu",
+ keylen, (long unsigned int) sm->ptk.tk_len);
+ return -1;
+ }
rsclen = wpa_cipher_rsc_len(sm->pairwise_cipher);
if (sm->proto == WPA_PROTO_RSN || sm->proto == WPA_PROTO_OSEN) {
@@ -730,6 +735,7 @@ static int wpa_supplicant_install_ptk(st
/* TK is not needed anymore in supplicant */
os_memset(sm->ptk.tk, 0, WPA_TK_MAX_LEN);
+ sm->ptk.tk_len = 0;
sm->ptk.installed = 1;
if (sm->wpa_ptk_rekey) {
@@ -1699,9 +1705,10 @@ static int wpa_supplicant_verify_eapol_k
os_memcpy(mic, key + 1, mic_len);
if (sm->tptk_set) {
os_memset(key + 1, 0, mic_len);
- wpa_eapol_key_mic(sm->tptk.kck, sm->tptk.kck_len, sm->key_mgmt,
- ver, buf, len, (u8 *) (key + 1));
- if (os_memcmp_const(mic, key + 1, mic_len) != 0) {
+ if (wpa_eapol_key_mic(sm->tptk.kck, sm->tptk.kck_len,
+ sm->key_mgmt,
+ ver, buf, len, (u8 *) (key + 1)) < 0 ||
+ os_memcmp_const(mic, key + 1, mic_len) != 0) {
wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
"WPA: Invalid EAPOL-Key MIC "
"when using TPTK - ignoring TPTK");
@@ -1724,9 +1731,10 @@ static int wpa_supplicant_verify_eapol_k
if (!ok && sm->ptk_set) {
os_memset(key + 1, 0, mic_len);
- wpa_eapol_key_mic(sm->ptk.kck, sm->ptk.kck_len, sm->key_mgmt,
- ver, buf, len, (u8 *) (key + 1));
- if (os_memcmp_const(mic, key + 1, mic_len) != 0) {
+ if (wpa_eapol_key_mic(sm->ptk.kck, sm->ptk.kck_len,
+ sm->key_mgmt,
+ ver, buf, len, (u8 *) (key + 1)) < 0 ||
+ os_memcmp_const(mic, key + 1, mic_len) != 0) {
wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
"WPA: Invalid EAPOL-Key MIC - "
"dropping packet");
@@ -3689,6 +3697,11 @@ int fils_process_assoc_resp(struct wpa_s
alg = wpa_cipher_to_alg(sm->pairwise_cipher);
keylen = wpa_cipher_key_len(sm->pairwise_cipher);
+ if (keylen <= 0 || (unsigned int) keylen != sm->ptk.tk_len) {
+ wpa_printf(MSG_DEBUG, "FILS: TK length mismatch: %u != %lu",
+ keylen, (long unsigned int) sm->ptk.tk_len);
+ goto fail;
+ }
rsclen = wpa_cipher_rsc_len(sm->pairwise_cipher);
wpa_hexdump_key(MSG_DEBUG, "FILS: Set TK to driver",
sm->ptk.tk, keylen);
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