release/5.2.35/rfkill-Fix-incorrect-check-to-avoid-NULL-pointer-der.patch

From 31715fd79c9ed129665b3e455516d0f8fb5390af Mon Sep 17 00:00:00 2001
From: Aditya Pakki <pakki001@umn.edu>
Date: Sun, 15 Dec 2019 09:34:08 -0600
Subject: [PATCH] rfkill: Fix incorrect check to avoid NULL pointer dereference

commit 6fc232db9e8cd50b9b83534de9cd91ace711b2d7 upstream.

In rfkill_register, the struct rfkill pointer is first derefernced
and then checked for NULL. This patch removes the BUG_ON and returns
an error to the caller in case rfkill is NULL.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Link: https://lore.kernel.org/r/20191215153409.21696-1-pakki001@umn.edu
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index f9b08a6d8dbe..d1a955c79219 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c
@@ -1002,10 +1002,13 @@ static void rfkill_sync_work(struct work_struct *work)
 int __must_check rfkill_register(struct rfkill *rfkill)
 {
 	static unsigned long rfkill_no;
-	struct device *dev = &rfkill->dev;
+	struct device *dev;
 	int error;
 
-	BUG_ON(!rfkill);
+	if (!rfkill)
+		return -EINVAL;
+
+	dev = &rfkill->dev;
 
 	mutex_lock(&rfkill_global_mutex);
 
-- 
2.7.4