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From: pageexec@freemail.hu
To: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Andy Lutomirski <luto@mit.edu>,
	x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org, Jesper Juhl <jj@chaosbits.net>,
	Borislav Petkov <bp@alien8.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Arjan van de Ven <arjan@infradead.org>,
	Jan Beulich <JBeulich@novell.com>,
	richard -rw- weinberger <richard.weinberger@gmail.com>,
	Mikael Pettersson <mikpe@it.uu.se>,
	Andi Kleen <andi@firstfloor.org>, Brian Gerst <brgerst@gmail.com>,
	Louis Rilling <Louis.Rilling@kerlabs.com>,
	Valdis.Kletnieks@vt.edu, Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] x86-64, vsyscalls: Rename UNSAFE_VSYSCALLS to COMPAT_VSYSCALLS
Date: Fri, 10 Jun 2011 01:33:29 +0200
Message-ID: <4DF15849.13114.243B8330@pageexec.freemail.hu> (raw)
In-Reply-To: <20110609070215.GD7734@elte.hu>

On 9 Jun 2011 at 9:02, Ingo Molnar wrote:

> * pageexec@freemail.hu <pageexec@freemail.hu> wrote:
> > so can i take it as your concession that the vsyscall feature is 
> > indeed a security problem and it's being randomized/(re)moved for 
> > security reasons?
> 
> Again, i made two statements:
> 
>   "That naming is borderline security FUD"
>   "It's only a security problem if there's a security hole elsewhere."
> 
> I stand by those statements and i reject your repeated attempts to 
> put words in my mouth that i did not say, such as:
> 
>    > you called this feature "borderline security FUD" [...]

it's no more putting words into your mouth than your own attempt:

> You generally seem to assume that security is an absolute goal 
> with no costs attached.

(for which i'm still waiting for an actual proof btw ;)

also, notice i didn't quote you ("..." or >... style), i simply paraphrased
what you said and explained why. i got no response to those arguments though
so i guess you conceded them. then why do you keep arguing the same nonsense?

> > how can the name be "borderline security FUD" but what the name 
> > refers to not be that? you see, we name things for a reason, mostly 
> > because we think the name has something to do with the thing it 
> > names, duh?
> 
> It's borderline security FUD because it suggests that keeping the 
> vsyscall around is in itself a security hole.

it's not a hole per se, rather it's an accessory to writing reliable
exploits (not only userland ones btw). that's the *only* reason this
patchset even exists. do you deny that? now, if you don't deny it then
you also agree that the current vsyscall page *is* a security problem
(problem != hole). therefore the suggested name for the config option
that removes it for good cannot be "borderline security FUD".

> As i outlined whether there's *another* bug that *can be exploited* is
> highly dependent on the usecase - while the Kconfig name made no such
> distinction. (For example a device maker might choose to keep the
> option enabled in some embedded usecase, those are pretty limited
> environments that have few vectors of attack.) 

but you see, your own argument defeats your point: if for another use
case the presence of the vsyscall page *is* a security hazard (like,
i don't know, every single server and desktop out there?) then *not*
making it clear in the option name *is* a problem. see how it cuts
both ways? what now? ;) prudent people err on the side of safety.

also if the above device maker disables it even if their devices would
never ever be exploited using the vsyscall page, they haven't lost anything.
heck, they'll have reduced their kernel image and gained some all too
important cycles ;).

> Anyway, repeating and explaining my arguments a dozen times

repeated - yes, explained - no, that's the problem. you didn't even address
what *i* said (how many questions of mine have you left unanswered?). i'm
guessing because you realized how wrong you were but you're not the kind of
person who'd admit it.

> did not make any difference to you, and there's a point where i have
> to stop wasting time on a person, so i've started filtering out your
> mails. If you want to send me any patches then please send it to any
> of my co-maintainers who will be able to review them. 

PS: thanks for the cycles^Wchuckles ;)


  reply index

Thread overview: 112+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-05 17:50 [PATCH v5 0/9] Remove syscall instructions at fixed addresses Andy Lutomirski
2011-06-05 17:50 ` [PATCH v5 1/9] x86-64: Fix alignment of jiffies variable Andy Lutomirski
2011-06-06  8:31   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2011-06-05 17:50 ` [PATCH v5 2/9] x86-64: Document some of entry_64.S Andy Lutomirski
2011-06-06  8:31   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2011-06-05 17:50 ` [PATCH v5 3/9] x86-64: Give vvars their own page Andy Lutomirski
2011-06-06  8:32   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2011-06-05 17:50 ` [PATCH v5 4/9] x86-64: Remove kernel.vsyscall64 sysctl Andy Lutomirski
2011-06-06  8:32   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2011-12-05 18:27   ` [PATCH v5 4/9] " Matthew Maurer
2011-06-05 17:50 ` [PATCH v5 5/9] x86-64: Map the HPET NX Andy Lutomirski
2011-06-06  8:33   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2011-06-05 17:50 ` [PATCH v5 6/9] x86-64: Remove vsyscall number 3 (venosys) Andy Lutomirski
2011-06-06  8:33   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2011-06-05 17:50 ` [PATCH v5 7/9] x86-64: Fill unused parts of the vsyscall page with 0xcc Andy Lutomirski
2011-06-06  8:34   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2011-06-05 17:50 ` [PATCH v5 8/9] x86-64: Emulate legacy vsyscalls Andy Lutomirski
2011-06-05 19:30   ` Ingo Molnar
2011-06-05 20:01     ` Andrew Lutomirski
2011-06-06  7:39       ` Ingo Molnar
2011-06-06  9:42       ` pageexec
2011-06-06 11:19         ` Andrew Lutomirski
2011-06-06 11:56           ` pageexec
2011-06-06 12:43             ` Andrew Lutomirski
2011-06-06 13:58               ` pageexec
2011-06-06 14:07                 ` Brian Gerst
2011-06-07 23:32                   ` pageexec
2011-06-07 23:49                     ` Andrew Lutomirski
2011-06-08  6:32                       ` pageexec
2011-06-06 15:26                 ` Ingo Molnar
2011-06-06 15:48                   ` pageexec
2011-06-06 15:59                     ` Ingo Molnar
2011-06-06 16:19                       ` pageexec
2011-06-06 16:47                         ` Ingo Molnar
2011-06-06 22:49                           ` pageexec
2011-06-06 22:57                             ` david
2011-06-07  9:07                               ` Ingo Molnar
2011-06-07  6:59                             ` Pekka Enberg
2011-06-07  8:30                             ` Ingo Molnar
2011-06-07 23:24                               ` pageexec
2011-06-08  5:55                                 ` Pekka Enberg
2011-06-08  6:19                                   ` pageexec
2011-06-08  6:48                                 ` Ingo Molnar
2011-06-08  9:02                                   ` pageexec
2011-06-08  9:11                                     ` Andi Kleen
2011-06-08  9:35                                       ` pageexec
2011-06-08 10:06                                         ` Andi Kleen
2011-06-08 10:26                                           ` pageexec
2011-06-08 10:39                                             ` Ingo Molnar
2011-06-08 10:35                                           ` Ingo Molnar
2011-06-08  9:15                                     ` Ingo Molnar
2011-06-08  7:16                                 ` Ingo Molnar
2011-06-08  9:29                                   ` pageexec
2011-06-06 14:01             ` Linus Torvalds
2011-06-06 14:55               ` pageexec
2011-06-06 15:33                 ` Ingo Molnar
2011-06-06 15:58                   ` pageexec
2011-06-06 15:41         ` Ingo Molnar
2011-06-06  8:34   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2011-06-06  8:35   ` [tip:x86/vdso] x86-64, vdso, seccomp: Fix !CONFIG_SECCOMP build tip-bot for Ingo Molnar
2011-06-07  7:49   ` [tip:x86/vdso] x86-64: Emulate legacy vsyscalls tip-bot for Andy Lutomirski
2011-06-07  8:03   ` tip-bot for Andy Lutomirski
2011-06-05 17:50 ` [PATCH v5 9/9] x86-64: Add CONFIG_UNSAFE_VSYSCALLS to feature-removal-schedule Andy Lutomirski
2011-06-06  8:34   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2011-06-06  8:46   ` [PATCH v5 9/9] " Linus Torvalds
2011-06-06  9:31     ` Andi Kleen
2011-06-06 10:39       ` pageexec
2011-06-06 13:56         ` Linus Torvalds
2011-06-06 18:46           ` pageexec
2011-06-06 20:40             ` Linus Torvalds
2011-06-06 20:51               ` Andrew Lutomirski
2011-06-06 21:54                 ` Ingo Molnar
2011-06-06 21:45               ` Ingo Molnar
2011-06-06 21:48                 ` Ingo Molnar
     [not found]                 ` <BANLkTi==uw_h78oaep1cCOCzwY0edLUU_Q@mail.gmail.com>
2011-06-07  8:03                   ` [PATCH, v6] x86-64: Emulate legacy vsyscalls Ingo Molnar
2011-06-06 21:53               ` [PATCH v5 9/9] x86-64: Add CONFIG_UNSAFE_VSYSCALLS to feature-removal-schedule pageexec
2011-06-06 14:44         ` Ingo Molnar
2011-06-06 15:01           ` pageexec
2011-06-06 15:15             ` Ingo Molnar
2011-06-06 15:29               ` pageexec
2011-06-06 16:54                 ` Ingo Molnar
2011-06-06 18:59           ` pageexec
2011-06-06 19:25             ` Ingo Molnar
2011-06-07  0:34               ` pageexec
2011-06-07  9:51                 ` Ingo Molnar
2011-06-07 23:24                   ` pageexec
2011-06-10 11:19                     ` Ingo Molnar
2011-06-14  0:48                       ` pageexec
2011-06-15 19:42                         ` Valdis.Kletnieks
2011-06-06 14:52         ` Ingo Molnar
2011-06-06 10:24     ` [PATCH] x86-64, vsyscalls: Rename UNSAFE_VSYSCALLS to COMPAT_VSYSCALLS Ingo Molnar
2011-06-06 11:20       ` pageexec
2011-06-06 12:47         ` Ingo Molnar
2011-06-06 12:48           ` Ingo Molnar
2011-06-06 18:04           ` pageexec
2011-06-06 19:12             ` Ingo Molnar
2011-06-07  0:02               ` pageexec
2011-06-07  9:56                 ` Ingo Molnar
2011-06-07 23:24                   ` pageexec
2011-06-09  6:48                     ` Ingo Molnar
2011-06-09 23:33                       ` pageexec
2011-06-07 10:05                 ` Ingo Molnar
2011-06-07 23:24                   ` pageexec
2011-06-09  7:02                     ` Ingo Molnar
2011-06-09 23:33                       ` pageexec [this message]
2011-06-07 10:13                 ` Ingo Molnar
2011-06-07 23:24                   ` pageexec
2011-06-06 12:19       ` Ted Ts'o
2011-06-06 12:33         ` Andrew Lutomirski
2011-06-06 12:37         ` Ingo Molnar
2011-06-06 14:34     ` [tip:x86/vdso] " tip-bot for Ingo Molnar
2011-06-05 20:05 ` [PATCH v5 0/9] Remove syscall instructions at fixed addresses Andrew Lutomirski

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