From: Borislav Petkov <bp@suse.de>
To: "Chang S. Bae" <chang.seok.bae@intel.com>,
Michael Kerrisk <mtk.manpages@gmail.com>
Cc: tglx@linutronix.de, mingo@kernel.org, luto@kernel.org,
x86@kernel.org, len.brown@intel.com, dave.hansen@intel.com,
hjl.tools@gmail.com, Dave.Martin@arm.com, mpe@ellerman.id.au,
tony.luck@intel.com, ravi.v.shankar@intel.com,
libc-alpha@sourceware.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
Fenghua Yu <fenghua.yu@intel.com>
Subject: Re: [PATCH v2 2/4] x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ
Date: Thu, 26 Nov 2020 18:44:18 +0100 [thread overview]
Message-ID: <20201126174418.GA29770@zn.tnic> (raw)
In-Reply-To: <20201119190237.626-3-chang.seok.bae@intel.com>
On Thu, Nov 19, 2020 at 11:02:35AM -0800, Chang S. Bae wrote:
> Historically, signal.h defines MINSIGSTKSZ (2KB) and SIGSTKSZ (8KB), for
> use by all architectures with sigaltstack(2). Over time, the hardware state
> size grew, but these constants did not evolve. Today, literal use of these
> constants on several architectures may result in signal stack overflow, and
> thus user data corruption.
>
> A few years ago, the ARM team addressed this issue by establishing
> getauxval(AT_MINSIGSTKSZ), such that the kernel can supply at runtime value
> that is an appropriate replacement on the current and future hardware.
>
> Add getauxval(AT_MINSIGSTKSZ) support to x86, analogous to the support
> added for ARM in commit 94b07c1f8c39 ("arm64: signal: Report signal frame
> size to userspace via auxv").
I don't see it documented here:
https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/man3/getauxval.3
Dunno, now that two architectures will have it, maybe that is good
enough reason to document it.
Adding Michael.
--
Regards/Gruss,
Boris.
SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg
next prev parent reply other threads:[~2020-11-26 17:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-19 19:02 [PATCH v2 0/4] x86: Improve Minimum Alternate Stack Size Chang S. Bae
2020-11-19 19:02 ` [PATCH v2 1/4] x86/signal: Introduce helpers to get the maximum signal frame size Chang S. Bae
2020-11-25 11:17 ` Borislav Petkov
2020-11-30 20:40 ` Bae, Chang Seok
2020-12-01 14:27 ` Borislav Petkov
2020-11-19 19:02 ` [PATCH v2 2/4] x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ Chang S. Bae
2020-11-26 17:44 ` Borislav Petkov [this message]
2020-11-27 9:30 ` Michael Kerrisk (man-pages)
2020-11-19 19:02 ` [PATCH v2 3/4] x86/signal: Prevent an alternate stack overflow before a signal delivery Chang S. Bae
2020-11-20 23:04 ` Jann Horn
2020-11-24 18:22 ` Bae, Chang Seok
2020-11-24 18:41 ` Jann Horn
2020-11-24 20:43 ` Bae, Chang Seok
2020-11-24 20:47 ` Jann Horn
2020-11-24 20:55 ` Bae, Chang Seok
2021-02-08 20:29 ` Bae, Chang Seok
2020-11-19 19:02 ` [PATCH v2 4/4] selftest/x86/signal: Include test cases for validating sigaltstack Chang S. Bae
2020-11-27 17:32 ` Borislav Petkov
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