From: Andi Kleen <ak@linux.intel.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@redhat.com>,
luto@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
torvalds@linux-foundation.org
Subject: Re: [PATCH v2 1/3] x86/entry: Clear extra registers beyond syscall arguments for 64bit kernels
Date: Mon, 5 Feb 2018 07:58:37 -0800 [thread overview]
Message-ID: <20180205155837.GK30338@tassilo.jf.intel.com> (raw)
In-Reply-To: <20180205114250.zd3nbe5yl2mnd54m@gmail.com>
> - There's various conditional pieces of entry code that run before any
> RBP-clobbering C function is called. While none of them has an exploitable
> Spectre 'gadget' at the moment, we'd have to consider this for every future
> change.
The Frame Pointer is always set up in assembler too, just in another macro.
There should be only a few pushes between this clear and the set up,
which are not exploitable.
But yes in the end it doesn't matter much either way so the ifdef
could be removed for slightly nicer looking code.
-Andi
next prev parent reply other threads:[~2018-02-05 15:58 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-04 17:43 [PATCH v2 0/3] x86/entry: Clear registers to sanitize speculative usages Dan Williams
2018-02-04 17:44 ` [PATCH v2 1/3] x86/entry: Clear extra registers beyond syscall arguments for 64bit kernels Dan Williams
2018-02-05 11:42 ` Ingo Molnar
2018-02-05 15:37 ` Andy Lutomirski
2018-02-05 16:30 ` Ingo Molnar
2018-02-05 16:37 ` Andy Lutomirski
2018-02-05 17:26 ` Josh Poimboeuf
2018-02-05 17:31 ` Andy Lutomirski
2018-02-05 17:48 ` Josh Poimboeuf
2018-02-05 15:58 ` Andi Kleen [this message]
2018-02-06 7:19 ` Ingo Molnar
2018-02-05 11:58 ` Ingo Molnar
2018-02-05 21:33 ` Dan Williams
2018-02-05 21:58 ` Linus Torvalds
2018-02-05 22:10 ` Andy Lutomirski
2018-02-05 22:19 ` Dan Williams
2018-02-05 22:22 ` Linus Torvalds
2018-02-05 22:25 ` Linus Torvalds
2018-02-04 17:44 ` [PATCH v2 2/3] x86/entry: Clear registers for 64bit exceptions/interrupts Dan Williams
2018-02-04 17:44 ` [PATCH v2 3/3] x86/entry: Clear registers for compat syscalls Dan Williams
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