DRM_IOCTL_MODE_CREATEPROPBLOB allows userspace to allocate arbitrary-sized property blobs backed by kernel memory.
Currently, the blob data allocation is not accounted to the allocating process's memory cgroup, allowing unprivileged users to trigger unbounded kernel memory consumption and potentially cause system-wide OOM. Mark the property blob data allocation with GFP_ACCOUNT so that the memory is properly charged to the caller's memcg. This ensures existing cgroup memory limits apply and prevents uncontrolled kernel memory growth without introducing additional policy or per-file limits. Changes since v1: - Drop the per-drm_file blob count limit. - Account blob data allocations to memcg via GFP_KERNEL_ACCOUNT instead. Signed-off-by: Xiao Kan <[email protected]> Signed-off-by: Xiao Kan <[email protected]> --- drivers/gpu/drm/drm_property.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_property.c b/drivers/gpu/drm/drm_property.c index 596272149..a34758712 100755 --- a/drivers/gpu/drm/drm_property.c +++ b/drivers/gpu/drm/drm_property.c @@ -562,7 +562,7 @@ drm_property_create_blob(struct drm_device *dev, size_t length, if (!length || length > INT_MAX - sizeof(struct drm_property_blob)) return ERR_PTR(-EINVAL); - blob = kvzalloc(sizeof(struct drm_property_blob)+length, GFP_KERNEL); + blob = kvzalloc(sizeof(struct drm_property_blob)+length, GFP_KERNEL_ACCOUNT); if (!blob) return ERR_PTR(-ENOMEM); -- 2.51.0
