Subject: [PATCH AUTOSEL 4.19 58/84] rfkill: Fix incorrect check to avoid NULL pointer dereference

From: Sasha Levin <[email-masked]>
Date: Fri, 27 Dec 2019 12:43:26 -0500

From: Aditya Pakki <[email-masked]>

[ Upstream commit 6fc232db9e8cd50b9b83534de9cd91ace711b2d7 ]

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 <[email-masked]>
Link: https://lore.kernel.org/r/[email-masked]
Signed-off-by: Johannes Berg <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 net/rfkill/core.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 1355f5ca8d22..2c0ac44741a0 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c
@@ -1014,10 +1014,13 @@ 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);
 
-- 
2.20.1