From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> [ Upstream commit 6f03bf43ee05b31d3822def2a80f11b3591c55b3 ] Kernel sends an empty NFTA_SET_USERDATA attribute with no value if userspace adds a set with no NFTA_SET_USERDATA attribute. Fixes: e6d8ecac9e68 ("netfilter: nf_tables: Add new attributes into nft_set to store user data.") Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/netfilter/nf_tables_api.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 1b8a53081632f..159ec1533c980 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -3204,7 +3204,8 @@ static int nf_tables_fill_set(struct sk_buff *skb, const struct nft_ctx *ctx, goto nla_put_failure; } - if (nla_put(skb, NFTA_SET_USERDATA, set->udlen, set->udata)) + if (set->udata && + nla_put(skb, NFTA_SET_USERDATA, set->udlen, set->udata)) goto nla_put_failure; desc = nla_nest_start(skb, NFTA_SET_DESC); -- 2.25.1