netdev - [PATCH AUTOSEL 5.4 122/187] rfkill: Fix incorrect check to avoid NULL pointer dereference

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Message-Id: <20191227174055.4923-122-sashal@kernel.org>
Date:   Fri, 27 Dec 2019 12:39:50 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Aditya Pakki <pakki001@....edu>,
        Johannes Berg <johannes.berg@...el.com>,
        Sasha Levin <sashal@...nel.org>,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 5.4 122/187] rfkill: Fix incorrect check to avoid NULL pointer dereference

From: Aditya Pakki <pakki001@....edu>

[ 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 <pakki001@....edu>
Link: https://lore.kernel.org/r/20191215153409.21696-1-pakki001@umn.edu
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 0bf9bf1ceb8f..6c089320ae4f 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);
 
-- 
2.20.1