* [PATCH 3.7-rc8] drm: Fix possible EDID memory allocation oops
@ 2012-12-05 19:00 Tim Gardner
2012-12-06 15:41 ` Alex Deucher
0 siblings, 1 reply; 2+ messages in thread
From: Tim Gardner @ 2012-12-05 19:00 UTC (permalink / raw)
To: linux-kernel; +Cc: Tim Gardner, David Airlie, dri-devel
The result of drm_property_create_blob() is not checked for success
which could lead to a NULL pointer dereference.
I was led to this by a smatch warning:
drivers/gpu/drm/drm_crtc.c:3186 drm_mode_connector_update_edid_property() error: potential null dereference 'connector->edid_blob_ptr'. (drm_property_create_blob returns null)
drm_property_create_blob() calls kzalloc() which can return NULL.
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Cc: stable@vger.kernel.org # 3.0+
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
This bug actually exists in the original commit f453ba0460742ad027ae0c4c7d61e62817b3e7ef
(2.6.29), but I only checked as far back as 3.0 for stable.
drivers/gpu/drm/drm_crtc.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index ef1b221..31872ba 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3180,6 +3180,10 @@ int drm_mode_connector_update_edid_property(struct drm_connector *connector,
size = EDID_LENGTH * (1 + edid->extensions);
connector->edid_blob_ptr = drm_property_create_blob(connector->dev,
size, edid);
+ if (!connector->edid_blob_ptr) {
+ pr_err("drm: Could not allocate %d edid blob bytes.\n", size);
+ return -ENOMEM;
+ }
ret = drm_connector_property_set_value(connector,
dev->mode_config.edid_property,
--
1.7.9.5
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH 3.7-rc8] drm: Fix possible EDID memory allocation oops
2012-12-05 19:00 [PATCH 3.7-rc8] drm: Fix possible EDID memory allocation oops Tim Gardner
@ 2012-12-06 15:41 ` Alex Deucher
0 siblings, 0 replies; 2+ messages in thread
From: Alex Deucher @ 2012-12-06 15:41 UTC (permalink / raw)
To: Tim Gardner; +Cc: linux-kernel, dri-devel
On Wed, Dec 5, 2012 at 2:00 PM, Tim Gardner <tim.gardner@canonical.com> wrote:
> The result of drm_property_create_blob() is not checked for success
> which could lead to a NULL pointer dereference.
>
> I was led to this by a smatch warning:
>
> drivers/gpu/drm/drm_crtc.c:3186 drm_mode_connector_update_edid_property() error: potential null dereference 'connector->edid_blob_ptr'. (drm_property_create_blob returns null)
>
> drm_property_create_blob() calls kzalloc() which can return NULL.
>
> Cc: David Airlie <airlied@linux.ie>
> Cc: dri-devel@lists.freedesktop.org
> Cc: stable@vger.kernel.org # 3.0+
> Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
> ---
>
> This bug actually exists in the original commit f453ba0460742ad027ae0c4c7d61e62817b3e7ef
> (2.6.29), but I only checked as far back as 3.0 for stable.
>
> drivers/gpu/drm/drm_crtc.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index ef1b221..31872ba 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -3180,6 +3180,10 @@ int drm_mode_connector_update_edid_property(struct drm_connector *connector,
> size = EDID_LENGTH * (1 + edid->extensions);
> connector->edid_blob_ptr = drm_property_create_blob(connector->dev,
> size, edid);
> + if (!connector->edid_blob_ptr) {
> + pr_err("drm: Could not allocate %d edid blob bytes.\n", size);
> + return -ENOMEM;
> + }
>
> ret = drm_connector_property_set_value(connector,
> dev->mode_config.edid_property,
> --
> 1.7.9.5
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
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