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@xxxxxxxxxx>
---
net/netfilter/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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;
--
2.7.4
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