[PATCH] netfilter: nf_tables: prevent shift wrap in nft_chain_parse_hook()

[Dan Carpenter]

I believe that "hook->num" can be up to UINT_MAX so the shift has to
be unsigned or shifting more than 31 is undefined.  It's possible that
this leads to array overflow in nf_tables_addchain():

        ops->hook       = hook.type->hooks[ops->hooknum];

Fixes: fe19c04ca137 ("netfilter: nf_tables: remove nhooks field from struct 
nft_af_info")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
---
 net/netfilter/nf_tables_api.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ef7772e976cc..b6e48fe7c776 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1545,7 +1545,7 @@ static int nft_chain_parse_hook(struct net *net,
                if (IS_ERR(type))
                        return PTR_ERR(type);
        }
-       if (!(type->hook_mask & (1 << hook->num)))
+       if (!(type->hook_mask & (1U << hook->num)))
                return -EOPNOTSUPP;
 
        if (type->type == NFT_CHAIN_T_NAT &&
-- 
2.17.1