UPSTREAM: netfilter: nf_tables: bail out on mismatching dynset and set expressions

[ Upstream commit 3701cd390fd731ee7ae8b8006246c8db82c72bea ]

If dynset expressions provided by userspace is larger than the declared
set expressions, then bail out.

Bug: 316085841
Fixes: 48b0ae046ee9 ("netfilter: nftables: netlink support for several set element expressions")
Reported-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit cf5f113c41eb2c7dbe19d849a0883f7a429fa54b)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I4bd3f7e9148d4bc12bbc67ecdd605c2957eb8010

net/netfilter/nft_dynset.c

diff --git a/net/netfilter/nft_dynset.c b/net/netfilter/nft_dynset.c
index cf9a1ae..a470e5f 100644
--- a/net/netfilter/nft_dynset.c
+++ b/net/netfilter/nft_dynset.c
@@ -279,10 +279,15 @@ static int nft_dynset_init(const struct nft_ctx *ctx,
 			priv->expr_array[i] = dynset_expr;
 			priv->num_exprs++;
 
-			if (set->num_exprs &&
-			    dynset_expr->ops != set->exprs[i]->ops) {
-				err = -EOPNOTSUPP;
-				goto err_expr_free;
+			if (set->num_exprs) {
+				if (i >= set->num_exprs) {
+					err = -EINVAL;
+					goto err_expr_free;
+				}
+				if (dynset_expr->ops != set->exprs[i]->ops) {
+					err = -EOPNOTSUPP;
+					goto err_expr_free;
+				}
 			}
 			i++;
 		}