release/5.2.35/cfg80211-fix-double-free-after-changing-network-name.patch

From 1f8fd7c44eb5be7adaa94db19cc4d48bf779f4bd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20B=C3=BChler?= <source@stbuehler.de>
Date: Tue, 26 Nov 2019 11:05:44 +0100
Subject: [PATCH] cfg80211: fix double-free after changing network namespace
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commit 56cb31e185adb61f930743a9b70e700a43625386 upstream.

If wdev->wext.keys was initialized it didn't get reset to NULL on
unregister (and it doesn't get set in cfg80211_init_wdev either), but
wdev is reused if unregister was triggered through
cfg80211_switch_netns.

The next unregister (for whatever reason) will try to free
wdev->wext.keys again.

Signed-off-by: Stefan Bühler <source@stbuehler.de>
Link: https://lore.kernel.org/r/20191126100543.782023-1-stefan.buehler@tik.uni-stuttgart.de
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/net/wireless/core.c b/net/wireless/core.c
index ed24a0b071c3..fa6353b9ca1e 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -1093,6 +1093,7 @@ static void __cfg80211_unregister_wdev(struct wireless_dev *wdev, bool sync)
 
 #ifdef CONFIG_CFG80211_WEXT
 	kzfree(wdev->wext.keys);
+	wdev->wext.keys = NULL;
 #endif
 	/* only initialized if we have a netdev */
 	if (wdev->netdev)
-- 
2.7.4