Re: [PATCH] drm/edid: fix info leak when failing to get panel id

[Doug Anderson]

Hi,

On Wed, Mar 1, 2023 at 11:49 PM Johan Hovold  wrote:
>
> Make sure to clear the transfer buffer before fetching the EDID to
> avoid leaking slab data to the logs on errors that leave the buffer
> unchanged.
>
> Fixes: 69c7717c20cc ("drm/edid: Dump the EDID when drm_edid_get_panel_id() 
> has an error")
> Cc: sta...@vger.kernel.org  # 6.2
> Cc: Douglas Anderson 
> Signed-off-by: Johan Hovold 
> ---
>  drivers/gpu/drm/drm_edid.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 3841aba17abd..8707fe72a028 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2797,7 +2797,7 @@ u32 drm_edid_get_panel_id(struct i2c_adapter *adapter)
>  * the EDID then we'll just return 0.
>  */
>
> -   base_block = kmalloc(EDID_LENGTH, GFP_KERNEL);
> +   base_block = kzalloc(EDID_LENGTH, GFP_KERNEL);

Good catch! I'm landing this to drm-misc-fixes right away.

4d8457fe0eb9 drm/edid: fix info leak when failing to get panel id

I'm sure I copied the kmalloc() from _drm_do_get_edid(), but it looks
like in _that_ case if the read fails we never print the buffer so
that one is OK.

-Doug

Re: [PATCH] drm/edid: fix info leak when failing to get panel id

[Jani Nikula]

On Thu, 02 Mar 2023, Johan Hovold  wrote:
> Make sure to clear the transfer buffer before fetching the EDID to
> avoid leaking slab data to the logs on errors that leave the buffer
> unchanged.
>
> Fixes: 69c7717c20cc ("drm/edid: Dump the EDID when drm_edid_get_panel_id() 
> has an error")
> Cc: sta...@vger.kernel.org# 6.2
> Cc: Douglas Anderson 
> Signed-off-by: Johan Hovold 

Reviewed-by: Jani Nikula 

> ---
>  drivers/gpu/drm/drm_edid.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 3841aba17abd..8707fe72a028 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2797,7 +2797,7 @@ u32 drm_edid_get_panel_id(struct i2c_adapter *adapter)
>* the EDID then we'll just return 0.
>*/
>  
> - base_block = kmalloc(EDID_LENGTH, GFP_KERNEL);
> + base_block = kzalloc(EDID_LENGTH, GFP_KERNEL);
>   if (!base_block)
>   return 0;

-- 
Jani Nikula, Intel Open Source Graphics Center

[PATCH] drm/edid: fix info leak when failing to get panel id

[Johan Hovold]

Make sure to clear the transfer buffer before fetching the EDID to
avoid leaking slab data to the logs on errors that leave the buffer
unchanged.

Fixes: 69c7717c20cc ("drm/edid: Dump the EDID when drm_edid_get_panel_id() has 
an error")
Cc: sta...@vger.kernel.org  # 6.2
Cc: Douglas Anderson 
Signed-off-by: Johan Hovold 
---
 drivers/gpu/drm/drm_edid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 3841aba17abd..8707fe72a028 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2797,7 +2797,7 @@ u32 drm_edid_get_panel_id(struct i2c_adapter *adapter)
 * the EDID then we'll just return 0.
 */
 
-   base_block = kmalloc(EDID_LENGTH, GFP_KERNEL);
+   base_block = kzalloc(EDID_LENGTH, GFP_KERNEL);
if (!base_block)
return 0;
 
-- 
2.39.2