5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: William Tu <u9012063@xxxxxxxxx> commit 51fa960d3b5163b1af22efdebcabfccc5d615ad6 upstream. Add a check to make sure the IFLA_GRE_ERSPAN_VER is provided by users. Fixes: f989d546a2d5 ("erspan: Add type I version 0 support.") Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx> Signed-off-by: William Tu <u9012063@xxxxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/ip_gre.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -1106,7 +1106,8 @@ static int erspan_validate(struct nlattr if (ret) return ret; - if (nla_get_u8(data[IFLA_GRE_ERSPAN_VER]) == 0) + if (data[IFLA_GRE_ERSPAN_VER] && + nla_get_u8(data[IFLA_GRE_ERSPAN_VER]) == 0) return 0; /* ERSPAN type II/III should only have GRE sequence and key flag */