diff mbox

[nf-next,1/2] netfilter: Fix potential null pointer dereference

Message ID 1474907071-13591-2-git-send-email-aconole@bytheb.org
State Awaiting Upstream, archived
Delegated to: David Miller
Headers show

Commit Message

Aaron Conole Sept. 26, 2016, 4:24 p.m. UTC
It's possible for nf_hook_entry_head to return NULL if two
nf_unregister_net_hook calls happen simultaneously with a single hook
entry in the list.  This fix ensures that no null pointer dereference
could occur when such a race happens.

Signed-off-by: Aaron Conole <aconole@bytheb.org>
---
 net/netfilter/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox

Patch

diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index 360c63d..e58e420 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -160,7 +160,7 @@  void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
 
 	mutex_lock(&nf_hook_mutex);
 	hooks_entry = nf_hook_entry_head(net, reg);
-	if (hooks_entry->orig_ops == reg) {
+	if (hooks_entry && hooks_entry->orig_ops == reg) {
 		nf_set_hooks_head(net, reg,
 				  nf_entry_dereference(hooks_entry->next));
 		goto unlock;