From: Borislav Petkov <bp@suse.de>
To: "Chang S. Bae" <chang.seok.bae@intel.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, jannh@google.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
Subject: Re: [PATCH v3 3/4] x86/signal: Prevent an alternate stack overflow before a signal delivery
Date: Fri, 8 Jan 2021 19:09:35 +0100 [thread overview]
Message-ID: <20210108180935.GB12995@zn.tnic> (raw)
In-Reply-To: <20201223015312.4882-4-chang.seok.bae@intel.com>
On Tue, Dec 22, 2020 at 05:53:11PM -0800, Chang S. Bae wrote:
> The kernel pushes data on the userspace stack when entering a signal. If
> using a sigaltstack(), the kernel precisely knows the user stack size.
^^^^^^^^^^^^^^^^^^^^^^^
Formulate properly.
>
> When the kernel knows that the user stack is too small, avoid the overflow
> and do an immediate SIGSEGV instead.
^^^^^^^^^^^^^^^^^^^^^^^
Ditto.
> This overflow is known to occur on systems with large XSAVE state. The
> effort to increase the size typically used for altstacks reduces the
^^^^^^^^^^
"alternate signal stacks"
--
Regards/Gruss,
Boris.
SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg
next prev parent reply other threads:[~2021-01-08 18:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-23 1:53 [PATCH v3 0/4] x86: Improve Minimum Alternate Stack Size Chang S. Bae
2020-12-23 1:53 ` [PATCH v3 1/4] x86/signal: Introduce helpers to get the maximum signal frame size Chang S. Bae
2020-12-23 1:53 ` [PATCH v3 2/4] x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ Chang S. Bae
2020-12-23 1:53 ` [PATCH v3 3/4] x86/signal: Prevent an alternate stack overflow before a signal delivery Chang S. Bae
2020-12-23 6:55 ` Jann Horn
2021-01-08 18:09 ` Borislav Petkov [this message]
2020-12-23 1:53 ` [PATCH v3 4/4] selftest/x86/signal: Include test cases for validating sigaltstack Chang S. Bae
2021-01-08 18:07 ` Borislav Petkov
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