Hírolvasó
[$] Ruff: a fast Python linter
Valgrind-3.21.0 released
The Guix (almost) full-source bootstrap
If you run guix pull today, you get a package graph of more than 22,000 nodes rooted in a 357-byte program—something that had never been achieved, to our knowledge, since the birth of Unix.
This is an interesting exercise, but should also be a defense against "trusting trust" attacks. (Thanks to Ludovic Courtès and Andy Tai).
Security updates for Tuesday
Újabb három aktívan kihasznált sérülékenységre figyelmeztet a CISA
Az Egyesült Államok Kiberbiztonsági és Infrastruktúra-biztonsági Ügynöksége (CISA) három új aktívan kihasznált sérülékenységgel bővítette az ismert módon kihasznált sérülékenységeket tartalmazó (KEV) listáját.
The post Újabb három aktívan kihasznált sérülékenységre figyelmeztet a CISA first appeared on Nemzeti Kibervédelmi Intézet.
Hatékonynak bizonyultak a Google tavalyi biztonsági törekvései
A Google nemrég közzétett jelentésében arról számol be, hogy közel 1,4 millió rosszindulatú alkalmazás közzétételét akadályozták meg és mintegy 173 ezer fejlesztői fiókot tiltottak ki a Play Store alkalmazásboltból 2022-ben. A Google szerint a megújuló irányelvek, a gépi tanuláson alapuló rendszerek és a folyamatos fejlesztés alatt álló alkalmazás-ellenőrzési folyamatok sokat segítettek a Play Store szabályzatát […]
The post Hatékonynak bizonyultak a Google tavalyi biztonsági törekvései first appeared on Nemzeti Kibervédelmi Intézet.
Nem jók az első tapasztalatok az Apple villám biztonsági frissítéseivel
Az Apple kiadta első soron kívüli villám biztonsági frissítést az iOS 16.4.1 és macOS 13.3.1 rendszerekhez, azonban egyes iPhone felhasználók arról számoltak be, hogy problémák adódtak a frissítések telepítése során.
The post Nem jók az első tapasztalatok az Apple villám biztonsági frissítéseivel first appeared on Nemzeti Kibervédelmi Intézet.
[$] A kernel without buffer heads
Four new stable kernels
Security updates for Monday
Game of Trees 0.88 released!
Version 0.88 of Game of Trees has been released (and the port updated): * got 0.88; 2023-04-29 see git repository history for per-change authorship information - tog: always use alternate charset for vertical/horizontal line - several tog regression test suite improvements - run the tog tests as part of the default regress set - tog: resize log view if toggling fullscreen from child view - when finding changed paths iterate tree entries in on-disk order for speed - cache fulltext data in delta cache to improve speed with long delta chains - gotwebd: fix logic error in gotweb_render_index
VM owners can now override the boot kernel
Dave Voutila (dv@) has added another feature to virtualisation on OpenBSD. Thanks to the following commit, it is now possible for the owners of virtual machines to override the boot kernel:
vmd(8) moves to a multi-process model
Dave Voutila (dv@) committed a change which brings a multi-process model to vmd(8), enhancing both security and performance:
CVSROOT: /cvs Module name: src Changes by: dv@cvs.openbsd.org 2023/04/27 16:47:27 Modified files: usr.sbin/vmd : Makefile dhcp.c vioqcow2.c vioraw.c virtio.c virtio.h vm.c vmd.c vmd.h vmm.c Added files: usr.sbin/vmd : vioblk.c vionet.c Log message: vmd(8): introduce multi-process model for virtio devices. Isolate virtio network and block device emulation in dedicated processes, forked and exec'd from the vm process. This allows for tightening pledge promises to just "stdio". Communication between the vcpu's and these devices now occurs via imsg channels, which adds the benefit of not always blocking the vcpu thread while emulating the device.SystemTap 4.9 released
[$] 6.4 Merge window, part 1
Debian "bookworm" release on June 10
Security updates for Friday
James Bottomley: Fixing our Self Defeating Licence Compatibility Problems in Open Source
Much angst (and discussion ink) is wasted in open source over whether pulling in code from one project with a different licence into another is allowable based on the compatibility of the two licences. I call this problem self defeating because it creates sequestered islands of incompatibly licensed but otherwise fully open source code that can never ever meet in combination. Everyone from the most permissive open source person to the most ardent free software one would agree this is a problem that should be solved, but most of the islands would only agree to it being solved on their terms. Practically, we have got around this problem by judicious use of dual licensing but that requires permission from the copyright holders, which can sometimes be hard to achieve; so dual licensing is more a band aid than a solution.
In this blog post, I’m going to walk you through the reasons behind cone the most intractable compatibility disputes in open source: Apache-2 vs GPLv2. However, before we get there, I’m first going to walk through several legal issues in general contract and licensing law and then get on to the law and politics of open source licensing.
The Law of Contracts and LicencesContracts and Licences come from very similar branches of the law and concepts that apply to one often apply to the other. For this legal tour we’ll begin with materiality in contracts followed by licences then look at repairable and irreparable legal harms and finally the conditions necessary to take court action.
Materiality in ContractsThis is actually a well studied and taught bit of the law. The essence is that every contract has a “heart” or core set of clauses which really represent what the parties want from each other and often has a set of peripheral clauses which don’t really affect the “heart” of the contract if they’re not fulfilled. Not fulfilling the latter are said to cause non-material breaches of the contract (i.e. breaches which don’t terminate the contract if they happen, although a party may still have an additional legal claim for the breach if it caused some sort of harm). A classic illustration, often used in law schools, is a contract for electrical the electrical wiring of a house that specifies yellow insulation. The contractor can’t find yellow, so wires the house with blue insulation. The contract doesn’t suffer a material breach because the wires are in the wall (where no-one can see) and there’s no safety issue with the colour and the heart of the contract was about wiring the house not about wire colour.
Materiality in LicensingThis is actually much less often discussed, but it’s still believed that licences are subject to the same materiality constraints as contracts and for this reason, licences often contain “materiality clauses” to describe what the licensor considers to be material to it. So for the licensing example, consider a publisher wishing to publish a book written by a famous author known as the “Red Writer”. A licence to publish for per copy royalties of 25% of the purchase price of the book is agreed but the author inserts a clause specifying by exact pantone number the red that must be the predominant colour of the binding (it’s why they’re known as the “Red Writer”) and also throws in a termination of copyright licence for breaches clause. The publisher does the first batch of 10,000 copies, but only after they’ve been produced discovers that the red is actually one pantone shade lighter than that specified in the licence. Since the cost of destroying the batch and reprinting is huge, the publisher offers the copies for sale knowing they’re out of spec. Some time later the “Red Writer” comes to know of the problem, decides the licence is breached and therefore terminated, so the publisher owes statutory damages (yes, they’ve registered their copyright) per copy on 10,000 books (about $300 million maximum), would the author win?
The answer of course is that no court is going to award the author $300 million. Most courts would take the view that the heart of the contract was about money and if the author got their royalties per book, there was no material breach and the licence continues in force for the publisher. The “Red Writer” may have a separate tort claim for reputational damage if any was caused by the mis-colouring of the book, but that’s it.
Open Source Enforcement and HarmLooking at the examples above, you can see that most commercial applications of the law eventually boil down to money: you go to court alleging a harm, the court must agree and then assess the monetary compensation for the harm which becomes damages. Long ago in community open source, we agreed that money could never compensate for a continuing licence violation because if it could we’d have set a price for buying yourself out of the terms of the licence (and some Silicon Valley Rich Companies would actually be willing to pay it, since it became the dual licence business model of companies like MySQL)1. The principle that mostly applies in open source enforcement actions is that the harm is to the open source ecosystem and is caused by non-compliance with the licence. Since such harm can only be repaired by compliance that’s the essence of the demand. Most enforcement cases have been about egregious breaches: lack of any source code rather than deficiencies in the offer to provide source code, so there’s actually very little in court records with regard to materiality of licence breaches.
One final thing to note about enforcement cases is there must always be an allegation of material harm to someone or something because you can’t go into court and argue on abstract legal principles (as we seem to like to do in various community mailing lists), you must show actual consequences as well. In addition to consequences, you must propose a viable remedy for the harm that a court could impose. As I said above in open source cases it’s often about harms to the open source ecosystem caused by licence breaches, which is often accepted unchallenged by the defence because the case is about something obviously harmful to open source, like failure to provide source code (and the remedy is correspondingly give us the source code). However, when considering about the examples below it’s instructive to think about how an allegation of harm around a combination of incompatible open source licences would play out. Since the source code is available, there would be much more argument over what the actual harm to the ecosystem, if any, was and even if some theoretical harm could be demonstrated, what would the remedy be?
Applying this to Apache-2 vs GPLv2The divide between the Apache Software Foundation (ASF) and the Free Software Foundation (FSF) is old and partly rooted in politics. For proof of this notice the FSF says that the two licences (GPLv2 and Apache-2) are legally incompatible and in response the ASF says no-one should use any GPL licences anyway. The purpose of this section is to guide you through the technicalities of the incompatibility and then apply the materiality lessons from above to see if they actually matter.
Why GPLv2 is Incompatible with Apache-2The argument is that Apache-2 contains two incompatible clauses: the patent termination clause (section 3) which says that if you launch an action against anyone alleging the licensed code infringes your patent then all your rights to patents in the code under the Apache-2 licence terminate; and the Indemnity clause (Section 9) which says that if you want to offer an a warranty you must indemnify every contributor against any liability that warranty might incur. By contrast, GPLv2 contains an implied patent licence (Section 7) and a No Warranty clause (Section 11). Licence scholars mostly agree that the patent and indemnity terms in GPLv2 are weaker than those in Apache-2.
The incompatibility now occurs because GPLv2 says in Section 2 that the entire work after the combination must be shipped under GPLv2, which is possible: Apache is mostly permissive except for the stronger patent and indemnity clauses. However, it is arguable that without keeping those stronger clauses on the Apache-2 code, you’ve violated the Apache-2 licence and the GPLv2 no additional restrictions clause (Section 6) prevents you from keeping the stronger licensing and indemnity clauses even on the Apache-2 portions of the code. Thus Apache-2 and GPLv2 are incompatible.
Materiality and IncompatibilityIt should be obvious from the above that it’s hard to make a materiality argument for dropping the stronger apache2 provisions because someone, somewhere might one day get into a situation where they would have helped. However, we can look at the materiality of the no additional restrictions clause in GPLv2. The FSF has always taken the absolutist position on this, which is why they think practically every other licence is GPLv2 incompatible: when you dig at least one clause in every other open source licence can be regarded as an additional restriction. We also can’t take the view that the whole clause is not material: there are obviously some restrictions (like you must pay me for every additional distribution of the code) that would destroy the open source nature of the licence. This is the whole point of the no additional restrictions clause: to prevent the downstream addition of clauses incompatible with the free software goal of the licence.
I mentioned in the section on Materiality in Licences that some licences have materiality clauses that try to describe what’s important to the licensor. It turns out that GPLv2 actually does have a materiality clause: the preamble. We all tend to skip the preamble when analysing the licence, but there’s no denying it’s 7 paragraphs of justification for why the licence looks like it does and what its goals are.
So, to take the easiest analysis first, does the additional indemnity Apache-2 requires represent a material additional restriction. The preamble actually says “for each author’s protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors’ reputations.” Even on a plain reading an additional strengthening of that by providing an indemnity to the original authors has to be consistent with the purpose as described, so the indemnity clause can’t be regarded as a material additional restriction (a restriction which would harm the aims of the licence) when read in combination with the preamble.
Now the patent termination clause. The preamble has this to say about patents “Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone’s free use or not licensed at all.” So giving licensees the ability to terminate the patent rights for patent aggressors would appear to be an additional method of fulfilling the last sentence. And, again, the patent termination clause seems to be consistent with the licence purpose and thus must also not be a material additional restriction.
Thus the final conclusion is that while the patent and indemnity clauses of Apache-2 do represent additional restrictions, they’re not material additional restrictions according to the purpose of the licence as outlined by its materiality clause and thus the combination is permitted. This doesn’t mean the combination is free of consequences: the added code still carries the additional restrictions and you must call that out to the downstream via some mechanism like licensing tags, but it can be done.
Proving ItThe only way to prove the above argument is to win in court on it. However, here lies the another good reason why combining Apache-2 and GPLv2 is allowed: there’s no real way to demonstrate harm to anything (either the copyright holder who agreed to GPLv2 or the Community) and without a theory of actual Harm, no-one would have standing to get to court to test the argument. This may look like a catch-22, but it’s another solid reason why, even in the absence of the materiality arguments, this would ultimately be allowed (if you can’t prevent it, it must be allowable, right …).
Community Problems with the Materiality ApproachThe biggest worry about the loosening of the “no additional restrictions” clause of the GPL is opening the door to further abuse of the licence by unscrupulous actors. While I agree that this should be a concern, I think it is adequately addressed by rooting the materiality of the licence in the preamble or in provable harm to the open source community. There is also the flip side of this: licences are first and foremost meant to serve the needs of their development community rather than become inflexible implements for a group of enforcers, so even if there were some putative additional abuse in this approach, I suspect it would be outweighed by the licence compatibility benefit to the development communities in general.
ConclusionThe first thing to note is that Open Source incompatible licence combination isn’t as easy as simply combining the code under a single licence: You have to preserve the essential elements of both licences in the code which is combined (although not necessarily the whole project), so for an Apache-2/GPLv2 combination, you’ll need a note on the files saying they follow the stronger Apache patent termination and indemnity even if they’re otherwise GPLv2. However, as long as you’re careful the combination works for either of two reasons: because the Apache-2 restrictions aren’t material additional restrictions under the GPLv2 preamble or because no-one was actually harmed in the making of the combination (or both).
One can see from the above that similar arguments can be applied to various other supposedly incompatible licence combinations (exercise for the reader: try it with BSD-4-Clause and GPLv2). One final point that should be made is that licences and contracts are also all about what was in the minds of the parties, so for open source licences on community code, the norms and practices of the community matter in addition to what the licence actually says and what courts have made of it. In the final analysis, if the community norm of, say, a GPLv2 project is to accept Apache-2 code allowing for the stronger patent and indemnity clauses, then that will become the understood basis for interpreting the GPLv2 licence in that community.
For completeness, I should point out I’ve used the no harm no foul reasoning before when arguing that CDDL and GPLv2 are compatible.