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how do you know i don't have cause? when you see how
https://bugzilla.redhat.com/show_bug.cgi?id=194215#c2 turns into this
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-... commit, there is cause.
"Stable" kernel 22.214.171.124
Posted Jun 11, 2008 2:51 UTC (Wed) by tialaramex (subscriber, #21167)
As spooky as it undoubtedly seems to you, the commit messages aren't addressed to PaXTeam (are
you actually an individual or a corporate entity?). Unless stated elsewhere they aren't
intended as a functional description of the changes (read the source for that), a summary of
the security consequences, an entry into a poetry contest, a running commentary on the
developer's lunch plans or a source of entropy for a random number generator. On occasion they
may serve as one or more of those things, but generally, they're a memo to the developers
working on that code. So if they fix a line which incorrectly sets foozle to NULL, don't be
surprised if the commit message is "don't touch foozle in baz" rather than "Potential security
flaw fixed, NULL dereference PaXTeam take note".
If you would like to provide blow-by-blow security commentary for every merge, I suspect at
least some people on LKML would welcome it, perhaps to a different list.
The general situation is that most bugs involving privileged code will have security
consequences. Since any large system, including all the popular general purpose operating
systems, will have such bugs, this is not very helpful information.
Posted Jun 11, 2008 8:49 UTC (Wed) by PaXTeam (subscriber, #24616)
you *still* don't understand what i was saying. for the Nth time: i am *not* talking about
commits lacking security impact information when it is *not* known at the time of the commit
(although one would think that in this age at least a few exploitable bug classes should be
known to kernel developers and be recognized and thus documented as such in the commit).
what i *am* talking about is commits where the security impact is already *known* yet the
commit very deliberately does *not* mention it or tries to downplay it as much as possible.
you want proof? the last one i mentioned, look at
https://bugzilla.redhat.com/show_bug.cgi?id=194215#c0 in the Red Hat bugzilla. the actual
author of that one was not Marcel Holtmann but Paul Mackerras himself. the problem? Marcel did
not quote the full email, he omitted one of the last paragraphs, as you will see below, for a
good reason (good for him and other kernel devs trying to evade full disclosure, something
they supposedly support, at least when it's for PR purposes, that is):
I'd appreciate advice about the best way forward here, and to what
degree we should be candid about the reason for the patch in the
commit message when it gets committed to Linus' git repository.
and candid it became indeed. if you want more juicy stuff, go ask your supposedly honest
kernel devs for the kernel security list archives.
PS: i hope you're not a kernel contributor, you certainly haven't got a clue about what
belongs into a commit message. you also don't have a clue about what bugs have a security
impact, it's most certainly not *most bugs*. but i understand, what i've been saying sounds
unbelievable to you, so it's easier to attack the messenger, instead of actually checking out
the situation for yourself.
"Candid" doesn't mean hidden
Posted Jun 11, 2008 9:48 UTC (Wed) by tialaramex (subscriber, #21167)
What you're talking about is commits which lack security impact information.
I explained that commit messages aren't specifically called out as a medium for security
impact information. So it doesn't matter if they don't have security impact information, any
more than it matters if they don't rhyme.
And you've responded to inform me that I "still don't understand" by which, so far as I've
been able to discover you mean simply that I didn't agree with you about how terrible this is.
Candid means frank and open. You may be confused by seeing it used in the context "candid
camera" or "candid photographs" which refer to the fact that the subject isn't aware that
they're being watched and so they act candidly. The developers involved decided /not/ to be
candid about the bug in your example. You're cross about that, we get it. But you still
haven't given me a reason to care.
I've encountered this claim that only a handful of bugs have security impact before. It's
disappointing, particularly when it comes from someone who claims to actually care about
security. I just picked at random a harmless sounding item from the latest stable tree commit
"eCryptfs: remove unnecessary page decrypt call"
... sounds like it's probably a performance fix? Let's take a look. Oh, the bug overwrites
mmap() changes, undoing them. The kernel promises not to do that to you, breaking the promise
converts to a security impact because userspace programs that rely on this promise are now
broken and their security assumptions are violated.
Posted Jun 11, 2008 13:04 UTC (Wed) by PaXTeam (subscriber, #24616)
> "Candid" doesn't mean hidden
i never said it did. what Paul was asking the kernel devs was about how honest he should be in
the commit. the mind boggles at that very moment as this was on a list whose declared
disclosure policy is full-disclosure (see Documentation/SecurityBugs if in doubt). then what
do we get in the commit? complete omission of the more serious security impact (arbitrary
kernel memory read). you call that whatever you want, i call it dishonesty. it's not terrible
per se, it's just it's in direct contradiction to what was communicated to the public before
and what this supposedly superiour development model is so proud of among others. as they say,
you can't have it both ways.
also, this one at least got a CVE that, as far as i know, you can't say about that ptrace bug
i posted somewhere above (not even the corresponding -stable commit mentions anything at least
yet the -stable guys were fully aware of its impact - this by the way directly contradicts
Chris Wright's claim in http://marc.info/?l=linux-kernel&m=121312896523183&... ).
> I explained that commit messages aren't specifically called out as a medium for security
says who? 'tialaramex' or is it the agreed-upon (read: documented for the public) commit
policy of kernel developers?
as for what percentage of kernel bugs have a security impact (or did you mean something other
than 'kernel code' by 'privileged code'?), i stand by my claim that it's not *most* of them (i
never said 'only a handful' either, nice strawman though). this is based on my personal
PS: congratulations on finding yet another silently fixed potential security bug.
Posted Jun 11, 2008 17:33 UTC (Wed) by tialaramex (subscriber, #21167)
If you use words in the opposite sense to their correct meaning without any trace of irony
then people certainly are entitled to assume that's because you don't actually know what they
mean. I see that a dose of your own medicine doesn't suit you.
You've several times provided links which actually don't say what you claim they do. This time
you suggested that the Linux security list has a policy of full disclosure, when in fact the
document you mentioned uses weasel words to declare that disclosure should happen "as soon as
possible" which means nothing at all.
No congratulations are necessary. I did not find a bug, I just read a randomly chosen commit
log. Anyone can do it. Maybe more people should.
Posted Jun 11, 2008 21:11 UTC (Wed) by PaXTeam (subscriber, #24616)
i see you're getting sidetracked into various things which is a good sign that i raised valid
points you don't contest.
> You've several times provided links which actually don't say what you
> claim they do.
this is a blanket statement without any proof/explanation. elaborate please.
> This time you suggested that the Linux security list has
> a policy of full disclosure, when in fact the document you mentioned
> uses weasel words to declare that disclosure should happen "as soon as
> possible" which means nothing at all.
said document talks about 'full disclosure', not mere 'disclosure' (nice attempt but you got
caught). second, if you cared to read the comment at the bottom of this thread, you'd realize
that said document doesn't at all raise the issue of the amount of disclosure, only its
potential timing. so we're in agreement that the disclosure policy is 'full disclosure' (and
which is what wasn't observed in several cases i cited). i've said nothing else and you
haven't contradicted it either. and frankly, if you're not an active party in all this
non-or-half-assed-disclosure process, you have zero idea about what you're talking.
Posted Jun 12, 2008 2:47 UTC (Thu) by tialaramex (subscriber, #21167)
Sorry everyone, I should not have fed the troll.
Posted Jun 12, 2008 3:14 UTC (Thu) by spender (subscriber, #23067)
Clever: when your lies are uncovered (see above post re: "full-disclosure"), you sneak out
while claiming the moral high ground.
If you're looking for a troll, you need only look in the mirror.
Posted Jun 12, 2008 19:03 UTC (Thu) by nix (subscriber, #2304)
This thread really is a confluence of the pointlessly combative, isn't it?
There's not an instant's consideration given to the possibility that any
disliked event might *not* be due to malice, `lies', `suppression'...
Posted Jun 12, 2008 20:49 UTC (Thu) by spender (subscriber, #23067)
One of us is privy to certain insider information, and one of us is not. I'm quite sure you
don't know what goes on in the private kernel security mailing lists (I'll include vendorsec
in on this as well). After a certain period of time, there's no reason to keep the
discussions of these lists private unless the members are embarrassed of the information that
would be found.
Go ask Linus if he didn't intentionally decide to cover up that ptrace bug mentioned in this
thread. I have proof that he did, and that as a result of the coverup no CVE was assigned and
the fix was not backported to distro kernels.
Go ask the members of the vendorsec list if they haven't been covering up a DoS on the Itanium
architecture reported by Intel over a year ago, for which two fixes were provided. The flaw
is in hardware so all kernels are vulnerable, and the worst part in this situation is that the
vendorsec members collectively agreed not to provide either of the two software fixes for the
You claim there's been no proof, but yet I've already pointed out in my previous exploit a
clear coverup of what was at least known to the committer to be a local DoS (I demonstrated
that it was trivial arbitrary code execution), but the commit message said only "fix
sys_tee()" and no CVE was created.
So many of those you blindly trust are involved in coverups like these. They erroneously
think they can get away with it because they don't think anyone's watching the watchers. So
people like Chris Wright will claim in public that there are no coverups, but he knows as we
know that he's taken part in it out of the public eye.
So I seriously encourage you or anyone else to go ask the people I've mentioned about the
specific events I've mentioned. Send this to LKML if you wish. I'll give them the
opportunity to give their side of the events in question. It should be clear to from the
details I've already released here that this is not a frivolous accusation, and that I'm aware
of things they hoped the public would never be aware of. If they choose not to, or continue
to lie about what happens behind the scenes, I'll release what information I have. I think
they'll be surprised by what is known among certain individuals about what they're doing.
I'm probably making enemies from all sides by even mentioning the details above, but in the
end a more honest security leadership will only help users of Linux. I'd also like to
reiterate the importance of making the discussions of the private kernel security lists public
after an agreed upon acceptable amount of time, so that this culture of coverups cannot be
allowed to grow any more.
Posted Jun 12, 2008 22:02 UTC (Thu) by nix (subscriber, #2304)
OK, you're resorting to argument from authority. There's absolutely no
point talking to you at all, is there?
(And no, I'm not going to go around randomly accusing kernel hackers of
coverups and conspiracies. You're the one arguing that point and referring
to secret evidence to 'support' your claim, not me.)
(I'd agree that the various private security lists should have delayed
public archives. Transparency is good, and the only reason to keep those
lists private is to prevent the bad guys from responding before the
distros do, so after they've responded there's no point keeping the
traffic secret anymore.)
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