* [PATCH] drm/fb-helper: Fix potential NULL pointer dereference
@ 2017-12-05 17:46 Gustavo A. R. Silva
2017-12-06 9:12 ` Daniel Vetter
0 siblings, 1 reply; 3+ messages in thread
From: Gustavo A. R. Silva @ 2017-12-05 17:46 UTC (permalink / raw)
To: Daniel Vetter, Jani Nikula, Gustavo Padovan, Sean Paul, David Airlie
Cc: dri-devel, linux-kernel, Gustavo A. R. Silva
fb_helper is being dereferenced before it is null checked,
hence there is a potential null pointer dereference.
Fix this by moving the pointer dereference after fb_helper
has been null checked.
This issue was detected with the help of Coccinelle.
Fixes: c777990fb45b ("drm/fb-helper: Handle function NULL argument")
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
drivers/gpu/drm/drm_fb_helper.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 6654f2f..04a3a5c 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -178,7 +178,7 @@ EXPORT_SYMBOL(drm_fb_helper_add_one_connector);
*/
int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
{
- struct drm_device *dev = fb_helper->dev;
+ struct drm_device *dev;
struct drm_connector *connector;
struct drm_connector_list_iter conn_iter;
int i, ret = 0;
@@ -186,6 +186,8 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
if (!drm_fbdev_emulation || !fb_helper)
return 0;
+ dev = fb_helper->dev;
+
mutex_lock(&fb_helper->lock);
drm_connector_list_iter_begin(dev, &conn_iter);
drm_for_each_connector_iter(connector, &conn_iter) {
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/fb-helper: Fix potential NULL pointer dereference
2017-12-05 17:46 [PATCH] drm/fb-helper: Fix potential NULL pointer dereference Gustavo A. R. Silva
@ 2017-12-06 9:12 ` Daniel Vetter
2017-12-06 17:07 ` Gustavo A. R. Silva
0 siblings, 1 reply; 3+ messages in thread
From: Daniel Vetter @ 2017-12-06 9:12 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Daniel Vetter, Jani Nikula, Gustavo Padovan, Sean Paul,
David Airlie, linux-kernel, dri-devel
On Tue, Dec 05, 2017 at 11:46:28AM -0600, Gustavo A. R. Silva wrote:
> fb_helper is being dereferenced before it is null checked,
> hence there is a potential null pointer dereference.
>
> Fix this by moving the pointer dereference after fb_helper
> has been null checked.
>
> This issue was detected with the help of Coccinelle.
>
> Fixes: c777990fb45b ("drm/fb-helper: Handle function NULL argument")
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Oops. Applied to drm-misc-next, thanks for your patch.
-Daniel
> ---
> drivers/gpu/drm/drm_fb_helper.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 6654f2f..04a3a5c 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -178,7 +178,7 @@ EXPORT_SYMBOL(drm_fb_helper_add_one_connector);
> */
> int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
> {
> - struct drm_device *dev = fb_helper->dev;
> + struct drm_device *dev;
> struct drm_connector *connector;
> struct drm_connector_list_iter conn_iter;
> int i, ret = 0;
> @@ -186,6 +186,8 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
> if (!drm_fbdev_emulation || !fb_helper)
> return 0;
>
> + dev = fb_helper->dev;
> +
> mutex_lock(&fb_helper->lock);
> drm_connector_list_iter_begin(dev, &conn_iter);
> drm_for_each_connector_iter(connector, &conn_iter) {
> --
> 2.7.4
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/fb-helper: Fix potential NULL pointer dereference
2017-12-06 9:12 ` Daniel Vetter
@ 2017-12-06 17:07 ` Gustavo A. R. Silva
0 siblings, 0 replies; 3+ messages in thread
From: Gustavo A. R. Silva @ 2017-12-06 17:07 UTC (permalink / raw)
To: Daniel Vetter
Cc: Daniel Vetter, Jani Nikula, Gustavo Padovan, Sean Paul,
David Airlie, linux-kernel, dri-devel
Quoting Daniel Vetter <daniel@ffwll.ch>:
> On Tue, Dec 05, 2017 at 11:46:28AM -0600, Gustavo A. R. Silva wrote:
>> fb_helper is being dereferenced before it is null checked,
>> hence there is a potential null pointer dereference.
>>
>> Fix this by moving the pointer dereference after fb_helper
>> has been null checked.
>>
>> This issue was detected with the help of Coccinelle.
>>
>> Fixes: c777990fb45b ("drm/fb-helper: Handle function NULL argument")
>> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
>
> Oops. Applied to drm-misc-next, thanks for your patch.
> -Daniel
>
Glad to help. :)
Thanks
--
Gustavo A. R. Silva
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-12-05 17:46 [PATCH] drm/fb-helper: Fix potential NULL pointer dereference Gustavo A. R. Silva
2017-12-06 9:12 ` Daniel Vetter
2017-12-06 17:07 ` Gustavo A. R. Silva
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