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From:   xiakaixu1987@gmail.com
To:     ast@kernel.org, daniel@iogearbox.net, kafai@fb.com,
        songliubraving@fb.com, yhs@fb.com, andrii@kernel.org,
        john.fastabend@gmail.com, kpsingh@chromium.org
Cc:     netdev@vger.kernel.org, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org, Kaixu Xia <kaixuxia@tencent.com>
Subject: [PATCH] bpf: Check the return value of dev_get_by_index_rcu()
Date:   Thu, 19 Nov 2020 15:04:28 +0800
Message-Id: <1605769468-2078-1-git-send-email-kaixuxia@tencent.com>
Precedence: bulk

From: Kaixu Xia <kaixuxia@tencent.com>

The return value of dev_get_by_index_rcu() can be NULL, so here it
is need to check the return value and return error code if it is NULL.

Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
---
 net/core/filter.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index 2ca5eecebacf..1263fe07170a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5573,6 +5573,8 @@ BPF_CALL_4(bpf_skb_fib_lookup, struct sk_buff *, skb,
 		struct net_device *dev;
 
 		dev = dev_get_by_index_rcu(net, params->ifindex);
+		if (unlikely(!dev))
+			return -EINVAL;
 		if (!is_skb_forwardable(dev, skb))
 			rc = BPF_FIB_LKUP_RET_FRAG_NEEDED;
 	}
-- 
2.20.0