From:   Jiasheng Jiang <jiasheng@iscas.ac.cn>
To:     jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
        davem@davemloft.net, kuba@kernel.org
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jiasheng Jiang <jiasheng@iscas.ac.cn>
Subject: [PATCH] net: sched: gred: potential dereference of null pointer
Date:   Thu,  9 Dec 2021 10:13:46 +0800
Message-Id: <20211209021346.2004600-1-jiasheng@iscas.ac.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The return value of kzalloc() needs to be checked.
To avoid use of null pointer in gred_change_vq() in case
of the failure of alloc.

Fixes: 869aa41044b0 ("sch_gred: prefer GFP_KERNEL allocations")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
 net/sched/sch_gred.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
index f4132dc25ac0..c0d355281baf 100644
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -697,6 +697,8 @@ static int gred_change(struct Qdisc *sch, struct nlattr *opt,
 	}
 
 	prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
+	if (!prealloc)
+		return -ENOMEM;
 	sch_tree_lock(sch);
 
 	err = gred_change_vq(sch, ctl->DP, ctl, prio, stab, max_P, &prealloc,
-- 
2.25.1