What if I don't receive a copy of the GPL license?

Question

I've downloaded the source for Linux device driver from the manufacturer's website. The source was included in a zip file, so no source control was involved. Unfortunately, the driver source was grossly out of date, so I have been working on porting it to more modern kernel versions.

The source files all seem to include a header at the top denoting a GPLv2 license as follows:

/******************************************************************************
 *
 * Copyright(c) 2007 - 2012 ACME Corporation. All rights reserved.
 *                                        
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
 *
 *
 ******************************************************************************/

I cannot, find anywhere in the files I downloaded, a copy of any sort of license. Could there be any issue, with me redistributing my modified version of this source code because of the lack of a license? There are other files, firmware binaries, etc. that I am unsure of the licensing terms for and don't know if those can be distributed either. Do I need to write said address in header?

Answer 1

There are two issues here:

1. ACME Corporation may have violated the GPL, if their files are a derivative work of somebody else's GPL'd code. They are supposed to supply you with a copy of the license, and they did not do that. But they cannot violate their own copyright, so if there is nobody upstream of them and if they do not accept non-CLA'd outside contributions, then there may be no violation at all. However, at a minimum, the Linux kernel is probably upstream of them in this sense. Regardless, their problem is not your problem - their violation of their license will not invalidate your license. If you want to pursue this violation, you might talk to the Software Freedom Conservancy, who tend to be very interested in this sort of thing but are not (usually) directly legally empowered to take action (the Linux kernel is a special case as some Linux developers have assigned their copyrights to the SFC). Nevertheless, they have a lot of practice at contacting violators and getting them into compliance.
2. It might be unclear which "GPL" they actually mean (for example, Brazil has a "General Public License", but it's non-free and not widely used). But I think this is very unlikely, given that they supply the mailing address of the Free Software Foundation. If you really want to, you can write to the FSF as it suggests to get a copy of the license, but the FSF will almost surely send you a word-for-word identical copy of the license on their website, so you may as well save the time and postage unless your lawyers advise you otherwise.