Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Lv Yunlong <lyl2019@mail.ustc.edu.cn>
To:     kuba@kernel.org, simon.horman@netronome.com, davem@davemloft.net,
        ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
        kafai@fb.com, songliubraving@fb.com, yhs@fb.com,
        john.fastabend@gmail.com, kpsingh@kernel.org
Cc:     netdev@vger.kernel.org, bpf@vger.kernel.org,
        oss-drivers@netronome.com, linux-kernel@vger.kernel.org,
        Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Subject: [PATCH] ethernet/netronome/nfp: Fix a use after free in nfp_bpf_ctrl_msg_rx
Date:   Mon, 29 Mar 2021 04:50:02 -0700
Message-Id: <20210329115002.8557-1-lyl2019@mail.ustc.edu.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In nfp_bpf_ctrl_msg_rx, if
nfp_ccm_get_type(skb) == NFP_CCM_TYPE_BPF_BPF_EVENT is true, the skb
will be freed. But the skb is still used by nfp_ccm_rx(&bpf->ccm, skb).

My patch adds a return when the skb was freed.

Fixes: bcf0cafab44fd ("nfp: split out common control message handling code")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
 drivers/net/ethernet/netronome/nfp/bpf/cmsg.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/cmsg.c b/drivers/net/ethernet/netronome/nfp/bpf/cmsg.c
index 0e2db6ea79e9..2ec62c8d86e1 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/cmsg.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/cmsg.c
@@ -454,6 +454,7 @@ void nfp_bpf_ctrl_msg_rx(struct nfp_app *app, struct sk_buff *skb)
 			dev_consume_skb_any(skb);
 		else
 			dev_kfree_skb_any(skb);
+		return;
 	}
 
 	nfp_ccm_rx(&bpf->ccm, skb);
-- 
2.25.1