netfilter: ctnetlink: avoid null pointer dereference

Dan Carpenter points out that deref occurs after NULL check, we should
re-fetch the pointer and check that instead.

Fixes: 2c205dd398 ("netfilter: add struct nf_nat_hook and use it")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2018-06-11 22:22:19 +02:00 committed by Pablo Neira Ayuso
parent adc972c5b8
commit c05a45c086
1 changed files with 2 additions and 1 deletions

View File

@ -1446,7 +1446,8 @@ ctnetlink_parse_nat_setup(struct nf_conn *ct,
}
nfnl_lock(NFNL_SUBSYS_CTNETLINK);
rcu_read_lock();
if (nat_hook->parse_nat_setup)
nat_hook = rcu_dereference(nf_nat_hook);
if (nat_hook)
return -EAGAIN;
#endif
return -EOPNOTSUPP;