[PATCH AUTOSEL 4.19 044/167] drm/amdgpu: validate user pitch alignment

[Sasha Levin]

From: Yu Zhao <yuzhao at google.com>

[ Upstream commit 89f23b6efef554766177bf51aa754bce14c3e7da ]

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.

Cc: stable at vger.kernel.org # v4.2+
Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>
Signed-off-by: Yu Zhao <yuzhao at google.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
index 686a26de50f91..6e67814d33e29 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
@@ -527,6 +527,16 @@ 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 = mode_cmd->pitches[0] / cpp;
+
+	pitch = amdgpu_align_pitch(adev, pitch, cpp, false);
+	if (mode_cmd->pitches[0] != pitch) {
+		DRM_DEBUG_KMS("Invalid pitch: expecting %d but got %d\n",
+			      pitch, mode_cmd->pitches[0]);
+		return ERR_PTR(-EINVAL);
+	}
 
 	obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[0]);
 	if (obj ==  NULL) {
-- 
2.20.1