[PATCH 5.4 026/111] ethernet/netronome/nfp: Fix a use after free in nfp_bpf_ctrl_msg_rx

[Greg Kroah-Hartman]

From: Lv Yunlong <lyl2...@mail.ustc.edu.cn>

commit 6e5a03bcba44e080a6bf300194a68ce9bb1e5184 upstream.

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 <lyl2...@mail.ustc.edu.cn>
Reviewed-by: Jakub Kicinski <k...@kernel.org>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/ethernet/netronome/nfp/bpf/cmsg.c |    1 +
 1 file changed, 1 insertion(+)

--- 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
                        dev_consume_skb_any(skb);
                else
                        dev_kfree_skb_any(skb);
+               return;
        }
 
        nfp_ccm_rx(&bpf->ccm, skb);