It's an amicus brief filed by DoJ with the Solicitor General's name of it - a man directly appointed by Obama in 2011. In more ways than even other DoJ briefs [1], there is a straight line from this to Obama, and surely if he wished to intervene to alter or prevent the submission of this brief he would have been able to.

To answer your question yes, in general, actions taken with direct authority or direction from high-level appointees of the President are described by the media as "White House" actions, with good reason.

[1] http://www.justice.gov/crt/about/app/briefs/fisher_appellee_...