The provision is part of H.R.4310 – National Defense Authorization Act for Fiscal Year 2013 passed by the 112th Congress (2011-2012).
Sources:
https://www.congress.gov/bill/112th-congress/house-bill/4310.
Government.
https://obamawhitehouse.archives.gov/the-press-office/2013/01/03/statement-president-hr-4310.
Government.
https://www.buzzfeednews.com/article/mhastings/congressmen-seek-to-lift-propaganda-ban.
News.
https://www.businessinsider.com/ndaa-legalizes-propaganda-2012-5.
Magazine.
https://foreignpolicy.com/2013/07/14/u-s-repeals-propaganda-ban-spreads-government-made-news-to-americans/.
Blog.
https://www.investmentwatchblog.com/the-controversy-surrounding-bill-hr-4310-does-it-give-the-news-media-freedom-to-disseminate-propaganda-to-the-american-people/.
Blog.
Related:
https://www.congress.gov/bill/114th-congress/senate-bill/2692.
Government.
https://www.congress.gov/bill/114th-congress/house-bill/6393.
Government.
https://www.congress.gov/bill/114th-congress/senate-bill/2943.
Government.
https://obamawhitehouse.archives.gov/the-press-office/2016/12/23/statement-president-signing-national-defense-authorization-act-fiscal.
Government.
https://www.zerohedge.com/news/2016-12-24/obama-signs-countering-disinformation-and-propaganda-act-law.
News.
https://www.congress.gov/bill/112th-congress/house-bill/5736.
Government.
This one did not become law.
https://www.usagm.gov/who-we-are/oversight/legislation/smith-mundt-faqs/.
Government.
http://www.smithmundt.com/about/.
General Website Link.
https://www.c-span.org/video/?519625-1/president-obama-warns-threat-disinformation-democracy.
Government, News, Video.
This speech was a keynote address to Stanford’s Cyber Policy Center. See the label on the lectern.
https://fsi.stanford.edu/news/securing-american-elections-report-offers-policy-road-map.
University.
I suppose we were too smart to pass the Smith-Mundt Modernization Act of 2012 but not smart enough to block it as part of the National Defense Authorization Act for Fiscal Year 2013.