[PATCH -stable,4.19 8/9] netfilter: nf_tables: validate NFTA_SET_ELEM_OBJREF based on NFT_SET_OBJECT flag

[Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>]

[ 5a2f3dc31811e93be15522d9eb13ed61460b76c8 ]

If the NFTA_SET_ELEM_OBJREF netlink attribute is present and
NFT_SET_OBJECT flag is set on, report EINVAL.

Move existing sanity check earlier to validate that NFT_SET_OBJECT
requires NFTA_SET_ELEM_OBJREF.

Fixes: 8aeff920dcc9 ("netfilter: nf_tables: add stateful object reference to set elements")
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
 net/netfilter/nf_tables_api.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 875ebdd8ddc8..9fe1c2e192e2 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4428,6 +4428,15 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 			return -EINVAL;
 	}
 
+	if (set->flags & NFT_SET_OBJECT) {
+		if (!nla[NFTA_SET_ELEM_OBJREF] &&
+		    !(flags & NFT_SET_ELEM_INTERVAL_END))
+			return -EINVAL;
+	} else {
+		if (nla[NFTA_SET_ELEM_OBJREF])
+			return -EINVAL;
+	}
+
 	if ((flags & NFT_SET_ELEM_INTERVAL_END) &&
 	     (nla[NFTA_SET_ELEM_DATA] ||
 	      nla[NFTA_SET_ELEM_OBJREF] ||
@@ -4462,10 +4471,6 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 	}
 
 	if (nla[NFTA_SET_ELEM_OBJREF] != NULL) {
-		if (!(set->flags & NFT_SET_OBJECT)) {
-			err = -EINVAL;
-			goto err2;
-		}
 		obj = nft_obj_lookup(ctx->table, nla[NFTA_SET_ELEM_OBJREF],
 				     set->objtype, genmask);
 		if (IS_ERR(obj)) {
-- 
2.30.2