From 31db78a4923ef5e2008f2eed321811ca79e7f71b Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Tue, 19 Sep 2023 08:34:15 +0200
Subject: [PATCH] wifi: mac80211: fix potential key use-after-free
Git-commit: 31db78a4923ef5e2008f2eed321811ca79e7f71b
Patch-mainline: v6.6-rc5
References: CVE-2023-52530 bsc#1220930
When ieee80211_key_link() is called by ieee80211_gtk_rekey_add()
but returns 0 due to KRACK protection (identical key reinstall),
ieee80211_gtk_rekey_add() will still return a pointer into the
key, in a potential use-after-free. This normally doesn't happen
since it's only called by iwlwifi in case of WoWLAN rekey offload
which has its own KRACK protection, but still better to fix, do
that by returning an error code and converting that to success on
the cfg80211 boundary only, leaving the error for bad callers of
ieee80211_gtk_rekey_add().
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: fdf7cb4185b6 ("mac80211: accept key reinstall without changing anything")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
net/mac80211/cfg.c | 3 +++
net/mac80211/key.c | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -456,6 +456,9 @@ static int ieee80211_add_key(struct wiph
sta->cipher_scheme = cs;
err = ieee80211_key_link(key, sdata, sta);
+ /* KRACK protection, shouldn't happen but just silently accept key */
+ if (err == -EALREADY)
+ err = 0;
out_unlock:
mutex_unlock(&local->sta_mtx);
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -675,7 +675,7 @@ int ieee80211_key_link(struct ieee80211_
*/
if (ieee80211_key_identical(sdata, old_key, key)) {
ieee80211_key_free_unused(key);
- ret = 0;
+ ret = -EALREADY;
goto out;
}