Re: [PATCH] media: renesas-ceu: fix a potential NULL pointer dereference

2019-03-09 Thread Jacopo Mondi
Hi Kangjie,
   thanks for the patch.

On Sat, Mar 09, 2019 at 01:14:24AM -0600, Kangjie Lu wrote:
> In case of_match_device cannot find a match, the check returns
> -EINVAL to avoid a potential NULL pointer dereference
>
> Signed-off-by: Kangjie Lu 
> ---
>  drivers/media/platform/renesas-ceu.c | 5 -
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/renesas-ceu.c 
> b/drivers/media/platform/renesas-ceu.c
> index 150196f7cf96..4aa807c0b6c7 100644
> --- a/drivers/media/platform/renesas-ceu.c
> +++ b/drivers/media/platform/renesas-ceu.c
> @@ -1682,7 +1682,10 @@ static int ceu_probe(struct platform_device *pdev)
>
>   if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
>   ceu_data = of_match_device(ceu_of_match, dev)->data;
> - num_subdevs = ceu_parse_dt(ceudev);
> + if (unlikely(!ceu_data))
> + num_subdevs = -EINVAL;
> + else
> + num_subdevs = ceu_parse_dt(ceudev);

I don't think this fix is required to be honest.

If we call of_match_device() here we're sure CONFIG_OF is enabled, and
if the driver probed, so a matching compatible string has proved to
exist.

Furthermore, if you want to protect against of_match_device()
returning a NULL pointer, you should change this line first, as it
would dereference an invalid pointer:

ceu_data = of_match_device(ceu_of_match, dev)->data;

but again, I don't think this might happen.

Thanks
   j

>   } else if (dev->platform_data) {
>   /* Assume SH4 if booting with platform data. */
>   ceu_data = _data_sh4;
> --
> 2.17.1
>


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[PATCH] media: renesas-ceu: fix a potential NULL pointer dereference

2019-03-08 Thread Kangjie Lu
In case of_match_device cannot find a match, the check returns
-EINVAL to avoid a potential NULL pointer dereference

Signed-off-by: Kangjie Lu 
---
 drivers/media/platform/renesas-ceu.c | 5 -
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/renesas-ceu.c 
b/drivers/media/platform/renesas-ceu.c
index 150196f7cf96..4aa807c0b6c7 100644
--- a/drivers/media/platform/renesas-ceu.c
+++ b/drivers/media/platform/renesas-ceu.c
@@ -1682,7 +1682,10 @@ static int ceu_probe(struct platform_device *pdev)
 
if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
ceu_data = of_match_device(ceu_of_match, dev)->data;
-   num_subdevs = ceu_parse_dt(ceudev);
+   if (unlikely(!ceu_data))
+   num_subdevs = -EINVAL;
+   else
+   num_subdevs = ceu_parse_dt(ceudev);
} else if (dev->platform_data) {
/* Assume SH4 if booting with platform data. */
ceu_data = _data_sh4;
-- 
2.17.1