[PATCH 5.15.y 5.10.y 5.4.y] wifi: mac80211: fix potential key use-after-free

[Sherry Yang <sherry.yang@oracle.com>]

From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit 31db78a4923ef5e2008f2eed321811ca79e7f71b ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[Sherry: bp to fix CVE-2023-52530, resolved minor conflicts in 
net/mac80211/cfg.c because of context change due to missing commit
23a5f0af6ff4 ("wifi: mac80211: remove cipher scheme support")
ccdde7c74ffd ("wifi: mac80211: properly implement MLO key handling")]
Signed-off-by: Sherry Yang <sherry.yang@oracle.com>
---
 net/mac80211/cfg.c | 3 +++
 net/mac80211/key.c | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index f652982a106b..c54b3be62c0a 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -511,6 +511,9 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
 		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);
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index f695fc80088b..7b427e39831b 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -843,7 +843,7 @@ int ieee80211_key_link(struct ieee80211_key *key,
 	 */
 	if (ieee80211_key_identical(sdata, old_key, key)) {
 		ieee80211_key_free_unused(key);
-		ret = 0;
+		ret = -EALREADY;
 		goto out;
 	}
 
-- 
2.46.0