[License-discuss] Source code availability after end of life
Bradley M. Kuhn
bkuhn at ebb.org
Thu Aug 16 22:51:29 UTC 2018
Sorry for reopening a thread from last week; I don't follow this list
closely and only happened to discover while skimming today that a GPL
compliance issue was under discussion here.
I do have a few comments on the thread that are hopefully useful:
Scott Peterson wrote on Wednesday, 8 August:
> There is no reason that a distributor of a product that includes software
> licensed under the GPL cannot use an upstream supplier's written offer as
> a part of compliance with the source availability requirement of the
> GPL. ...
> That written offer is real; requests sent in response to that written
> offer are fulfilled. That downstream distributor has not failed to comply
> with the GPL merely because it did not write its own written offer and did
> not not implement its own separate fulfillment process for receiving
> requests and sending source code responses.
Scott's analysis is of course correct as to the requirements of GPL, but I'm
glad we're discussing this in detail publicly, as there are some nuances
worth exploring. (Transparency and public discourse about these topics will
surely benefit the whole community.)
Most of my comments below aren't about the minimum requirements per the
license text, but rather discussing about best practices around this issue.
I generally find that seeking to meet the bare minimum requirements of the
license has limited utility in copyleft compliance discussions; it's better
to seek the best practice that will yield compliance practices that are
Thus, as a best practice, I urge all redistributors to avoid the written
offer entirely (more on that below). Moreover, certainly in the case of a
commercial actor, in most real-world scenarios, the written offer from
upstream is likely to be inadequate in practice even though it might be
adequate in theory (as Scott pointed out).
In my experience, only white-box repackagers of products ever use the binary
build precisely as upstream provided in a manner that would mean the
required "scripts used to control compilation and installation of the
executable" remain absolutely identical for upstream and downstream. I've
never seen a scenario in GPL enforcement where the upstream CCS complied,
because invariably the downstream vendor's engineers made changes and the
legal staff hadn't realized it. Most often, this is around the build and
installation. Too often, the build scripts requirement is (sadly)
forgotten, so it's easy for even well-intentioned downstreams to err
(because they don't read GPLv3§3/GPLv3§6 carefully), and then realize only
later the source offered by upstream is incorrect source (per "Complete,
Correspond Source" (CCS) definitions in the various GPL versions).
Furthermore, note that Scott's analysis assumes that the upstream source,
when shipped, will actually comply with other requirements (e.g., GPLv2§3)
of the GPL. In my experience, most upstreams have GPLv3§3/GPLv3§6
compliance problems. In other words, if you don't verify yourself
(regularly) that your upstream's offer, when exercised, puts GPL-compliant
CCS in the requestor's hands, you'll find out your upstream failed to comply
at the latest possible moment -- when someone tests what is now *your* offer
for source. You're then left scrambling and have set yourself up to fail.
BTW, as a copyleft drafting matter, the entire "offer for source" idea is
an annoying necessity. It assures that full source code provisioning at
point-of-sale doesn't cost-prohibit commercial incorporation of GPL'd
software in inexpensive devices. However, the only advisable time to use
offer for source is when it's truly financially unviable to distribute
physical-media source at time of physical distribution.
Relatedly, it's important to note that the companies who nefariously violate
the GPL have used the offer for source for more than a decade as a way to
cover up their intentional violations (more on that below). Contrary to
popular belief, there *are* many bad actor GPL violators who simply publish
an offer for source with no intention of fulfilling it properly if asked.
They hope that no one asks during the (usually short) sales lifecycle of the
product, and while the offer is indeed valid for three years after
distribution (GPLv2) or EOL (GPLv3), it's relatively rare that someone
requests source on an EOL'd product. Such companies play the odds and get
away with violations over and over again.
More reading on this issue can be found in the Comprehensive Copyleft Guide.
This issue is discussed in various sections (search for "offer" in the whole
text of the book available at https://copyleft.org/guide/monolithic/ to find
them all), but the section directly linked via
deals with the issue directly.
On Bruce's point:
Bruce Perens wrote on Wednesday, 8 August:
>> It's also possible for a company, including the upstream manufacturer, to
>> formally contract to perform another entity's GPL source code
This was quite a trend a few years ago, and a few companies in the
compliance industrial complex even attempted to offer such contracts as a
fee-for-service business. I don't get the impression this was successful,
because contracting out CD/DVD printing fulfillment is a commodity service,
and if you need any services beyond that, you're basically asking for GPL
compliance help anyway -- so you might as well train your staff in house how
to comply correctly as that expertise will pay dividends going forward for
I thus really don't recommend outsourcing any of your GPL requirements. I
do, however, recommend a public-accessible website with all source releases
for every product. While this does fail to comply with the offer provisions
for GPLv2-only, it *does* usually mean the number of people who will request
physical media goes down to zero or near-zero, as the only ones who need it
are those who lack speedy Internet connections. A sample offer that works
in this particular way is given in the second Copyleft Guide URL I mentioned
Scott wrote further:
> If what matters is the name on the offer (not whether the offer is
> effective), then that would be a GPL that serves the interests of
> troll-oriented "compliance enforcement", not the interests that the GPL
> seeks to serve. I do not believe that that is what is intended in the GPL.
While I do generally agree with this point, I think it might be overstated
for these two reasons:
First, I don't think there is *any* serious threat from troll-like
enforcement in any event; that risk has been unreasonably exaggerated.
Second, and relatedly, the violators who attempt to play games around the
offer clause behave much worse, such that it easily drowns out any concern
of bad enforcement behavior. In my experience, many violators (both the
nefarious and lazy varieties) have a tendency toward "hide the ball"
activity around the offer clauses. This is easier explained by giving a few
examples of why violators have told me they ignored offer requests:
* "You didn't have the address on the envelope character-for-character as
it appeared on the offer page, therefore, we weren't required to honor
* "You're not our customer."
* "You can't provide an address in the USA for delivery of your source CD,
so we aren't required to provide the source to you."
* "You sent your request via services with tracking, and we only accept
source requests with a plain, regular stamped envelope with no tracking
or signature required."
The GPL of course doesn't allow for any of these excuses, or the dozens of
others of the "but the dog ate your source request" variety that I've heard
from violators over the years. In most of these cases, compliance was
achieved in the usual way by following the Principles of Community-Oriented
GPL Enforcement, and thus I'm not bringing this up to admonish those who
behaved this way, but rather to point out that for every one of the times I
(or someone bothered to report a violation) have been told something like
this when requesting source, I'd suspect there are hundreds of people out
there are getting specious answers to their source requests -- who just give
up entirely. That pandemic problem (and the other pandemic problems of
non-compliance), so much outweigh any threat from one bad-actor-enforcer who
"once-upon-a-time made an argument not supported by the license text", that
the latter seems risible to me as a concern. I think we should continue to
read copyleft licenses with an eye toward assuring its requirements advance
software freedom, and include any requirements that succeed in that regard,
even if they are on rare occasions abused. IMO, the place for worrying
about what bad-actor-copyright-holders is in meta-documents like the
Principles of Community-Oriented GPL Enforcement, not the license itself.
Bradley M. Kuhn
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