From: Pavel Machek <pavel@ucw.cz>
To: Andy Lutomirski <luto@amacapital.net>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>,
"Joerg Roedel" <joro@8bytes.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@kernel.org>, "Peter Anvin" <hpa@zytor.com>,
"the arch/x86 maintainers" <x86@kernel.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
"Andrew Lutomirski" <luto@kernel.org>,
"Dave Hansen" <dave.hansen@intel.com>,
"Josh Poimboeuf" <jpoimboe@redhat.com>,
"Jürgen Groß" <jgross@suse.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Borislav Petkov" <bp@alien8.de>, "Jiri Kosina" <jkosina@suse.cz>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Brian Gerst" <brgerst@gmail.com>,
"David Laight" <David.Laight@aculab.com>,
"Denys Vlasenko" <dvlasenk@redhat.com>,
"Eduardo Valentin" <eduval@amazon.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Will Deacon" <will.deacon@arm.com>,
"Liguori, Anthony" <aliguori@amazon.com>,
"Daniel Gruss" <daniel.gruss@iaik.tugraz.at>,
"Hugh Dickins" <hughd@google.com>,
"Kees Cook" <keescook@google.com>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Waiman Long" <llong@redhat.com>,
"David H . Gutteridge" <dhgutteridge@sympatico.ca>,
"Joerg Roedel" <jroedel@suse.de>,
"Arnaldo Carvalho de Melo" <acme@kernel.org>,
"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
"Jiri Olsa" <jolsa@redhat.com>,
"Namhyung Kim" <namhyung@kernel.org>
Subject: Re: [PATCH 0/3] PTI for x86-32 Fixes and Updates
Date: Mon, 23 Jul 2018 23:55:57 +0200 [thread overview]
Message-ID: <20180723215557.GA3935@amd> (raw)
In-Reply-To: <39A1C149-DA03-46D1-801F-0205DCD69A36@amacapital.net>
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Hi!
> > What I want is "if A can ptrace B, and B has pti disabled, A can have
> > pti disabled as well". Now.. I see someone may want to have it
> > per-thread, because for stuff like javascript JIT, thread may have
> > rights to call ptrace, but is unable to call ptrace because JIT
> > removed that ability... hmm...
>
> No, you don’t want that. The problem is that Meltdown isn’t a problem that exists in isolation. It’s very plausible that JavaScript code could trigger a speculation attack that, with PTI off, could read kernel memory.
Yeah, the web browser threads that run javascript code should have PTI
on. But maybe I want the rest of web browser with PTI off.
So... yes, I see why someone may want it per-thread (and not
per-process).
I guess per-process would be good enough for me. Actually, maybe even
per-uid. I don't have any fancy security here, so anything running uid
0 and 1000 is close enough to trusted.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2018-07-23 21:55 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-20 16:22 [PATCH 0/3] PTI for x86-32 Fixes and Updates Joerg Roedel
2018-07-20 16:22 ` [PATCH 1/3] perf/core: Make sure the ring-buffer is mapped in all page-tables Joerg Roedel
2018-07-20 17:06 ` Andy Lutomirski
2018-07-20 17:48 ` Joerg Roedel
2018-07-20 19:32 ` Andy Lutomirski
2018-07-20 21:37 ` Joerg Roedel
2018-07-20 22:20 ` Andy Lutomirski
2018-07-21 21:06 ` Linus Torvalds
2018-07-20 19:27 ` Thomas Gleixner
2018-07-20 19:33 ` Andy Lutomirski
2018-07-20 19:43 ` Thomas Gleixner
2018-07-20 19:53 ` Thomas Gleixner
2018-07-20 19:37 ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-20 20:36 ` tip-bot for Joerg Roedel
2018-07-20 16:22 ` [PATCH 2/3] x86/entry/32: Check for VM86 mode in slow-path check Joerg Roedel
2018-07-20 19:37 ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-20 20:37 ` tip-bot for Joerg Roedel
2018-07-21 16:06 ` [PATCH 2/3] " Pavel Machek
2018-07-20 16:22 ` [PATCH 3/3] x86/entry/32: Copy only ptregs on paranoid entry/exit path Joerg Roedel
2018-07-20 17:09 ` Andy Lutomirski
2018-07-20 21:42 ` Joerg Roedel
2018-07-23 3:49 ` [PATCH 0/3] PTI for x86-32 Fixes and Updates David H. Gutteridge
2018-07-23 7:29 ` Joerg Roedel
2018-07-26 3:47 ` David H. Gutteridge
2018-07-23 14:09 ` Pavel Machek
2018-07-23 19:00 ` Linus Torvalds
2018-07-23 21:38 ` Pavel Machek
2018-07-23 21:50 ` Andy Lutomirski
2018-07-23 21:55 ` Pavel Machek [this message]
2018-07-24 21:18 ` Pavel Machek
2018-07-23 21:59 ` Josh Poimboeuf
2018-07-23 22:07 ` Dave Hansen
2018-07-24 13:39 ` Pavel Machek
2018-07-24 14:39 ` Andy Lutomirski
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