From: Raymond Jennings <shentino-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>,
Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
X86 ML <x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Brian Gerst <brgerst-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>,
Jann Horn <jann-XZ1E9jl8jIdeoWH0uzbU5w@public.gmane.org>,
Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
Tycho Andersen
<tycho.andersen-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
Subject: Re: [PATCH 0/3] ABI CHANGE!!! Remove questionable remote SP reads
Date: Tue, 04 Oct 2016 00:06:58 -0700 [thread overview]
Message-ID: <1475564818.7361.12@smtp.gmail.com> (raw)
In-Reply-To: <CA+55aFzo0xpbxbajpgcfyYoLyKihCiyMfgc+yCJ+b9ohw6wycQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
My personal opinion is that even looking at esp/rsp is asking for
trouble. The only reliable information is VM_STACK or another VM flag
that makes the area expand in response to stack growth.
Besides, userspace could always play funky trampoline games with the
stack pointer, or even dynamically expand the stack by doing a malloc
if a stack overflow draws near, which would put the stack in the data
section temporarily.
As long as esp is in the bounds of a valid VMA, my vote is that we
should consider it undefined how the task uses it.
On Mon, Oct 3, 2016 at 4:17 PM, Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> wrote:
> On Mon, Oct 3, 2016 at 4:08 PM, Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
> wrote:
>>
>> Ping!
>>
>> We need to decide fairly soon whether to apply these (or perhaps
>> just
>> patch 1 or just patches 2 and 3) for 4.9. For any parts that aren't
>> applied, I'll send quick fixups to pin the stack in the offending
>> code.
>
> I think we should apply it. Hopefully nothing uses it, and nobody will
> notice. And if somebody *does* notice, the sooner we find out, the
> better.
>
> Linus
next prev parent reply other threads:[~2016-10-04 7:06 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-30 17:58 [PATCH 0/3] ABI CHANGE!!! Remove questionable remote SP reads Andy Lutomirski
2016-09-30 17:58 ` [PATCH 2/3] proc: Stop trying to report thread stacks Andy Lutomirski
2016-10-20 11:13 ` [tip:mm/urgent] fs/proc: " tip-bot for Andy Lutomirski
[not found] ` <cover.1475257877.git.luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2016-09-30 17:58 ` [PATCH 1/3] proc: Stop reporting eip and esp in /proc/PID/stat Andy Lutomirski
[not found] ` <a5fed4c3f4e33ed25d4bb03567e329bc5a712bcc.1475257877.git.luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2016-09-30 18:56 ` Jann Horn
[not found] ` <20160930185642.GH14666-J1fxOzX/cBvk1uMJSBkQmQ@public.gmane.org>
2016-10-01 2:01 ` Andy Lutomirski
[not found] ` <CALCETrUBmsoUK5Shkjwo6n=BGaHFtZhhUZ=2uOcAzWUend-BXg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-10-01 4:22 ` Linus Torvalds
2016-10-01 10:37 ` Jann Horn
[not found] ` <20161001103728.GM14666-J1fxOzX/cBvk1uMJSBkQmQ@public.gmane.org>
2016-10-14 18:25 ` Andy Lutomirski
2016-10-14 20:01 ` Tycho Andersen
2016-10-20 11:13 ` [tip:mm/urgent] fs/proc: " tip-bot for Andy Lutomirski
2016-11-01 14:36 ` [4.9-rc3] BUG: unable to handle kernel paging request at ffffc900144dfc60 Tetsuo Handa
2016-11-01 23:47 ` Linus Torvalds
2016-11-02 10:50 ` Tetsuo Handa
[not found] ` <201611021950.FEJ34368.HFFJOOMLtQOVSF-JPay3/Yim36HaxMnTkn67Xf5DAMn2ifp@public.gmane.org>
2016-11-02 14:05 ` Andy Lutomirski
2016-11-02 14:54 ` Linus Torvalds
2016-11-03 6:32 ` Ingo Molnar
2016-09-30 17:58 ` [PATCH 3/3] mm: Change vm_is_stack_for_task() to vm_is_stack_for_current() Andy Lutomirski
2016-10-20 11:14 ` [tip:mm/urgent] " tip-bot for Andy Lutomirski
2016-10-03 23:08 ` [PATCH 0/3] ABI CHANGE!!! Remove questionable remote SP reads Andy Lutomirski
[not found] ` <CALCETrULWhzph=kpbQUQSEkmsm6ZaRtp_bV9j5LFaFjLkawwMw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-10-03 23:17 ` Linus Torvalds
[not found] ` <CA+55aFzo0xpbxbajpgcfyYoLyKihCiyMfgc+yCJ+b9ohw6wycQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-10-04 7:06 ` Raymond Jennings [this message]
2016-10-14 18:26 ` Andy Lutomirski
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