Hello.
On 07/06/2016 05:23 PM, Pablo Neira Ayuso wrote:
From: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
Since we cannot make sure that the 'hook_mask' will always be none
zero here.
Non-zero, you mean?
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@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
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 c69c892..8aff34e 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1460,6 +1460,9 @@ xt_hook_ops_alloc(const struct xt_table *table, nf_hookfn *fn)
uint8_t hooknum;
struct nf_hook_ops *ops;
+ if (!num_hooks)
+ return ERR_PTR(-EINVAL);
+
ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL);
BTW, asking to be kcalloc() instead?
[...]
MBR, Sergei
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