[V3] clk: vc5: Add memory check to prevent oops

Commit Message

Adam Ford July 16, 2020, 12:26 p.m. UTC

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 -ENOMEM error instead of blindly moving on.

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

Suggested-by: Dan Carpenter <[e-mail]>
Signed-off-by: Adam Ford <[e-mail]>
Reviewed-by: Luca Ceresoli <[e-mail]>
---
V3:   Fix spelling error, and use the style of checking (!variable) instead of
      (variable == NULL)

V2:   Fix an issue where a goto was going to use an unitialized variable.

Comments

Stephen Boyd July 21, 2020, 9:19 a.m. UTC | #1

Quoting Adam Ford (2020-07-16 05:26:20)
> 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 -ENOMEM error instead of blindly moving on.
> 
> Fixes: 260249f929e8 ("clk: vc5: Enable addition output configurations of the Versaclock")
> 
> Suggested-by: Dan Carpenter <[e-mail]>
> Signed-off-by: Adam Ford <[e-mail]>
> Reviewed-by: Luca Ceresoli <[e-mail]>
> ---
> V3:   Fix spelling error, and use the style of checking (!variable) instead of
>       (variable == NULL)
> 
> V2:   Fix an issue where a goto was going to use an unitialized variable.

Is the patch from Colin also needed?
https://lore.kernel.org/r/[e-mail]

Luca Ceresoli July 21, 2020, 10:10 a.m. UTC | #2

Hi Stephen,

On 21/07/20 11:19, Stephen Boyd wrote:
> Quoting Adam Ford (2020-07-16 05:26:20)
>> 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 -ENOMEM error instead of blindly moving on.
>>
>> Fixes: 260249f929e8 ("clk: vc5: Enable addition output configurations of the Versaclock")
>>
>> Suggested-by: Dan Carpenter <[e-mail]>
>> Signed-off-by: Adam Ford <[e-mail]>
>> Reviewed-by: Luca Ceresoli <[e-mail]>
>> ---
>> V3:   Fix spelling error, and use the style of checking (!variable) instead of
>>       (variable == NULL)
>>
>> V2:   Fix an issue where a goto was going to use an unitialized variable.
> 
> Is the patch from Colin also needed?
> https://lore.kernel.org/r/[e-mail]

The two patches look completely orthogonal.

Stephen Boyd July 23, 2020, 1:46 a.m. UTC | #3

Quoting Adam Ford (2020-07-16 05:26:20)
> 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 -ENOMEM error instead of blindly moving on.
> 
> Fixes: 260249f929e8 ("clk: vc5: Enable addition output configurations of the Versaclock")
> 
> Suggested-by: Dan Carpenter <[e-mail]>
> Signed-off-by: Adam Ford <[e-mail]>
> Reviewed-by: Luca Ceresoli <[e-mail]>
> ---

Applied to clk-next

Patch

diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
index 9a5fb3834b9a..9a37168c4afc 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)
+		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;
 }
 
@@ -828,7 +830,7 @@  static int vc5_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	int ret;
 
 	vc5 = devm_kzalloc(&client->dev, sizeof(*vc5), GFP_KERNEL);
-	if (vc5 == NULL)
+	if (!vc5)
 		return -ENOMEM;
 
 	i2c_set_clientdata(client, vc5);