netfilter: nf_tables: Add null check for nla_nest_start_noflag() in nft_dump_basechain_hook()

The nla_nest_start_noflag() function may fail and return NULL;
the return value needs to be checked.

Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with SVACE.

Fixes: d54725c ("netfilter: nf_tables: support for multiple devices per netdev hook")
Signed-off-by: Gavrilov Ilia <[email protected]>
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>

Author: Gavrilov Ilia

net/netfilter/nf_tables_api.c

@@ -1600,6 +1600,8 @@ static int nft_dump_basechain_hook(struct sk_buff *skb, int family,
 
 	if (nft_base_chain_netdev(family, ops->hooknum)) {
 		nest_devs = nla_nest_start_noflag(skb, NFTA_HOOK_DEVS);
+		if (!nest_devs)
+			goto nla_put_failure;
 
 		if (!hook_list)
 			hook_list = &basechain->hook_list;