netfilter: x_tables: fix possible ZERO_SIZE_PTR pointer dereferencing error.
Since we cannot make sure that the 'hook_mask' will always be none
zero here. If it equals to zero, the num_hooks will be zero too,
and then kmalloc() will return ZERO_SIZE_PTR, which is (void *)16.
Then the following error check will fails:
ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL);
if (ops == NULL)
return ERR_PTR(-ENOMEM);
So this patch will fix this with just doing the zero check before
kmalloc() is called.
Maybe the case above will never happen here, but in theory.
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index c69c892..8aff34e 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1460,6 +1460,9 @@
uint8_t hooknum;
struct nf_hook_ops *ops;
+ if (!num_hooks)
+ return ERR_PTR(-EINVAL);
+
ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL);
if (ops == NULL)
return ERR_PTR(-ENOMEM);