When creating frame buffer, userspace may request to attach to a
previously allocated GEM object that is smaller than what GPU
requires. Validation must be done to prevent out-of-bound DMA,
otherwise it could be exploited to reveal sensitive data.
This fix is not done in a common code path because individual
driver might have different requirement.
Cc: stable@xxxxxxxxxxxxxxx # v4.2+
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
index 16af80ccd0a0..61c075a78ee1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
@@ -527,6 +527,7 @@ amdgpu_display_user_framebuffer_create(struct drm_device *dev,
struct drm_gem_object *obj;
struct amdgpu_framebuffer *amdgpu_fb;
int ret;
+ int height;
struct amdgpu_device *adev = dev->dev_private;
int cpp = drm_format_plane_cpp(mode_cmd->pixel_format, 0);
int pitch = mode_cmd->pitches[0] / cpp;
@@ -557,6 +558,13 @@ amdgpu_display_user_framebuffer_create(struct drm_device *dev,
return ERR_PTR(-EINVAL);
}
+ height = ALIGN(mode_cmd->height, 8);
+ if (obj->size < pitch * height) {
+ DRM_DEBUG_KMS("Invalid GEM size: expecting >= %d but got %zu\n",
+ pitch * height, obj->size);
+ return ERR_PTR(-EINVAL);
+ }
+
amdgpu_fb = kzalloc(sizeof(*amdgpu_fb), GFP_KERNEL);
if (amdgpu_fb == NULL) {
drm_gem_object_put_unlocked(obj);
--
2.20.1.415.g653613c723-goog
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