netfilter: nf_tables: underflow in nft_parse_u32_check()

We don't want to allow negatives here.

Fixes: 36b701fae12a ('netfilter: nf_tables: validate maximum value of u32 netlink attributes')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index b70d3ea..24db222 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4423,7 +4423,7 @@ static int nf_tables_check_loops(const struct nft_ctx *ctx,
  */
 unsigned int nft_parse_u32_check(const struct nlattr *attr, int max, u32 *dest)
 {
-       int val;
+       u32 val;
 
        val = ntohl(nla_get_be32(attr));
        if (val > max)