From b51b394f4ab10af7feccdfb5dd85cb55f02ffc2a Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Sat, 2 May 2020 20:09:25 -0700
Subject: [PATCH] net_sched: sch_skbprio: add message validation to
 skbprio_change()

[ Upstream commit 2761121af87de45951989a0adada917837d8fa82 ]

Do not assume the attribute has the right size.

Fixes: aea5f654e6b7 ("net/sched: add skbprio scheduler")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sched/sch_skbprio.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/sched/sch_skbprio.c b/net/sched/sch_skbprio.c
index 0fb10abf7579..7a5e4c454715 100644
--- a/net/sched/sch_skbprio.c
+++ b/net/sched/sch_skbprio.c
@@ -169,6 +169,9 @@ static int skbprio_change(struct Qdisc *sch, struct nlattr *opt,
 {
 	struct tc_skbprio_qopt *ctl = nla_data(opt);
 
+	if (opt->nla_len != nla_attr_size(sizeof(*ctl)))
+		return -EINVAL;
+
 	sch->limit = ctl->limit;
 	return 0;
 }