[PATCH V2] clk: vc5: Add memory check to prevent oops

[PATCH V2] clk: vc5: Add memory check to prevent oops

[Adam Ford]

When getting the names of the child nodes, kasprintf is used to
allocate memory which is used to create the string for the node
name.  Unfortunately, there is no memory check to determine
if this allocation fails, it may cause an error when trying
to get child node name.

This patch will check if the memory allocation fails, and returns
and -NOMEM error instead of blindly moving on.

Fixes: 260249f929e8 ("clk: vc5: Enable addition output configurations of the Versaclock")

Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Adam Ford <aford173@gmail.com>

diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
index 9a5fb3834b9a..926a370a0eda 100644
--- a/drivers/clk/clk-versaclock5.c
+++ b/drivers/clk/clk-versaclock5.c
@@ -789,10 +789,13 @@ static int vc5_get_output_config(struct i2c_client *client,
 	int ret = 0;
 
 	child_name = kasprintf(GFP_KERNEL, "OUT%d", clk_out->num + 1);
+	if (child_name == NULL)
+		return -ENOMEM;
+
 	np_output = of_get_child_by_name(client->dev.of_node, child_name);
 	kfree(child_name);
 	if (!np_output)
-		goto output_done;
+		return 0;
 
 	ret = vc5_update_mode(np_output, clk_out);
 	if (ret)
@@ -813,7 +816,6 @@ static int vc5_get_output_config(struct i2c_client *client,
 
 	of_node_put(np_output);
 
-output_done:
 	return ret;
 }
 
-- 
2.17.1

Re: [PATCH V2] clk: vc5: Add memory check to prevent oops

[Luca Ceresoli]

Hi Adam,

On 06/07/20 22:37, Adam Ford wrote:
> When getting the names of the child nodes, kasprintf is used to
> allocate memory which is used to create the string for the node
> name.  Unfortunately, there is no memory check to determine
> if this allocation fails, it may cause an error when trying
> to get child node name.
> 
> This patch will check if the memory allocation fails, and returns
> and -NOMEM error instead of blindly moving on.

s/-NOMEM/-ENOMEM/

With this possibly fixed:
Reviewed-by: Luca Ceresoli <luca@lucaceresoli.net>

-- 
Luca