From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Topi Miettinen <toiwoton@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>,
Topi Miettinen via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [RFC PATCH 0/3] Improved ALSR
Date: Tue, 24 Nov 2020 09:47:46 +0000 [thread overview]
Message-ID: <20201124094745.GJ20578@arm.com> (raw)
In-Reply-To: <82a5ab37-521a-fc9e-7b24-3f1a93991e8d@gmail.com>
The 11/23/2020 20:16, Topi Miettinen via Libc-alpha wrote:
> On 23.11.2020 18.44, Florian Weimer wrote:
> > And the series only changes the TCB allocation for the main thread.
> > Fixing thread TCB/stack collocation is a completely different matter
> > (and probably the more significant issue than lack of ASLR).
>
> I thought I covered all uses of sbrk(), perhaps I missed that one. Does the
> thread TCB/stack allocation use sbrk()?
the point is that thread stack and tls is allocated
as one block (with mmap, but that does not matter).
you want at least a guard page in between, so stack
corruption does not clobber tcb/tls data.
but this has costs (kernel side vma) and significant
work in glibc (separate tls and stack size accounting).
prev parent reply other threads:[~2020-11-24 9:48 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-04 13:09 Topi Miettinen
2020-10-04 13:09 ` [RFC PATCH 1/3] csu: randomize location of TCB Topi Miettinen
2020-11-24 18:44 ` Adhemerval Zanella
2020-10-04 13:09 ` [RFC PATCH 2/3] malloc: always use mmap() to improve ASLR Topi Miettinen
2020-10-04 13:09 ` [RFC PATCH 3/3] dl-sysdep: disable remaining calls to sbrk() Topi Miettinen
2020-11-23 16:06 ` [RFC PATCH 0/3] Improved ALSR Topi Miettinen
2020-11-23 16:41 ` Szabolcs Nagy
2020-11-23 17:55 ` Topi Miettinen
2020-11-23 21:45 ` Florian Weimer
2020-11-23 22:28 ` Topi Miettinen
2020-11-24 11:24 ` Florian Weimer
2020-11-24 11:59 ` Topi Miettinen
2020-11-24 14:29 ` Adhemerval Zanella
2020-11-30 10:28 ` Florian Weimer
2020-11-30 11:39 ` Topi Miettinen
2020-11-23 16:44 ` Florian Weimer
2020-11-23 18:16 ` Topi Miettinen
2020-11-24 9:47 ` Szabolcs Nagy [this message]
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