[PATCH 2/3] drm/amd: validate user pitch alignment
Michel Dänzer
michel at daenzer.net
Fri Dec 21 09:07:26 UTC 2018
On 2018-12-21 4:10 a.m., Yu Zhao wrote:
> Userspace may request pitch alignment that is not supported by GPU.
> Some requests 32, but GPU ignores it and uses default 64 when cpp is
> 4. If GEM object is allocated based on the smaller alignment, GPU
> DMA will go out of bound.
>
> For GPU that does frame buffer compression, DMA writing out of bound
> memory will cause memory corruption.
>
> Signed-off-by: Yu Zhao <yuzhao at google.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> index e309d26170db..755daa332f8a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> @@ -527,6 +527,15 @@ amdgpu_display_user_framebuffer_create(struct drm_device *dev,
> struct drm_gem_object *obj;
> struct amdgpu_framebuffer *amdgpu_fb;
> int ret;
> + struct amdgpu_device *adev = dev->dev_private;
> + int cpp = drm_format_plane_cpp(mode_cmd->pixel_format, 0);
> + int pitch = amdgpu_align_pitch(adev, mode_cmd->width, cpp, false);
Also, this needs to use mode_cmd->pitches[0] instead of mode_cmd->width,
otherwise it'll spuriously fail for larger but well-aligned pitches.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
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