From: Cong Wang cong.wang@bytedance.com
[ Upstream commit 085c7c4e1c0e50d90b7d90f61a12e12b317a91e2 ]
Both version 0 and version 1 use ETH_P_ERSPAN, but version 0 does not have an erspan header. So the check in gre_parse_header() is wrong, we have to distinguish version 1 from version 0.
We can just check the gre header length like is_erspan_type1().
Fixes: cb73ee40b1b3 ("net: ip_gre: use erspan key field for tunnel lookup") Reported-by: syzbot+f583ce3d4ddf9836b27a@syzkaller.appspotmail.com Cc: William Tu u9012063@gmail.com Cc: Lorenzo Bianconi lorenzo.bianconi@redhat.com Signed-off-by: Cong Wang cong.wang@bytedance.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/gre_demux.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv4/gre_demux.c +++ b/net/ipv4/gre_demux.c @@ -128,7 +128,7 @@ int gre_parse_header(struct sk_buff *skb * to 0 and sets the configured key in the * inner erspan header field */ - if (greh->protocol == htons(ETH_P_ERSPAN) || + if ((greh->protocol == htons(ETH_P_ERSPAN) && hdr_len != 4) || greh->protocol == htons(ETH_P_ERSPAN2)) { struct erspan_base_hdr *ershdr;