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@vger.kernel.org # v4.2+ Signed-off-by: Yu Zhao yuzhao@google.com --- 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);