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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
        syzbot <syzkaller@googlegroups.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.19 08/48] net_sched: sch_skbprio: add message validation to skbprio_change()
Date:   Wed, 13 May 2020 11:44:34 +0200
Message-Id: <20200513094354.050443366@linuxfoundation.org>
In-Reply-To: <20200513094351.100352960@linuxfoundation.org>
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From: Eric Dumazet <edumazet@google.com>

[ 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(+)

--- a/net/sched/sch_skbprio.c
+++ b/net/sched/sch_skbprio.c
@@ -173,6 +173,9 @@ static int skbprio_change(struct Qdisc *
 {
 	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;
 }