Since we cannot make sure 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 fix this with just doing the zero check before calling
kmalloc() is called.
Maybe the case above will never happen here, but in theory.
Signed-off-by: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
---
net/netfilter/x_tables.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index c8a0b7d..4df8e38 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1185,6 +1185,9 @@ struct nf_hook_ops *xt_hook_link(const struct xt_table *table, nf_hookfn *fn)
struct nf_hook_ops *ops;
int ret;
+ if (!num_hooks)
+ return ERR_PTR(-EINVAL);
+
ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL);
if (ops == NULL)
return ERR_PTR(-ENOMEM);
--
1.8.3.1
--
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