[PATCH 4.14 18/65] netfilter: nf_tables: add NFTA_SET_USERDATA if not null

[Greg Kroah-Hartman]

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 5b8d5bfeb7ac5..7c95314f0b7de 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2882,7 +2882,8 @@ 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