From: Andi Kleen <ak@linux.intel.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Andi Kleen <andi@firstfloor.org>,
tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, dwmw@amazon.co.uk, pjt@google.com,
luto@kernel.org, peterz@infradead.org, thomas.lendacky@amd.com,
tim.c.chen@linux.intel.com, gregkh@linux-foundation.org,
dave.hansen@intel.com, jikos@kernel.org
Subject: Re: [PATCH v1 6/8] x86/entry/clearregs: Add number of arguments to syscall tables
Date: Tue, 9 Jan 2018 20:37:51 -0800 [thread overview]
Message-ID: <20180110043751.GK6718@tassilo.jf.intel.com> (raw)
In-Reply-To: <CEE66310-5B09-4375-8B9F-23D9798C8295@amacapital.net>
On Tue, Jan 09, 2018 at 05:26:43PM -0800, Andy Lutomirski wrote:
>
>
> > On Jan 9, 2018, at 5:03 PM, Andi Kleen <andi@firstfloor.org> wrote:
> >
> > From: Andi Kleen <ak@linux.intel.com>
> >
> > In order to sanitize the system call arguments properly
> > we need to know the number of syscall arguments for each
> > syscall. Add a new column to the 32bit and 64bit syscall
> > tables to list the number of arguments.
> >
>
> Surely we can do this in the SYSCALL_DEFINE macros. Or at least statically check it.
Possibly. The assembler would be much uglier as inline assembler though.
And adding the number shouldn't be a big burden when adding a system call.
I don't know how to check statically.
>
> Also, what attack are we protecting against anyway?
There's no specific attack here.
But the idea is to make it harder to inject values into the kernel to abuse
with speculation.
-Andi
next prev parent reply other threads:[~2018-01-10 4:38 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-10 1:03 x86/clearregs: Register sanitizing at kernel entry for speculation hygiene Andi Kleen
2018-01-10 1:03 ` [PATCH v1 1/8] x86/entry/clearregs: Remove partial stack frame in fast system call Andi Kleen
2018-01-10 2:46 ` Brian Gerst
2018-01-11 0:16 ` Andi Kleen
2018-01-11 0:54 ` Brian Gerst
2018-01-11 1:02 ` Andi Kleen
2018-01-11 0:55 ` Andy Lutomirski
2018-01-11 1:01 ` Andi Kleen
2018-01-11 1:01 ` Brian Gerst
2018-01-11 1:22 ` Andy Lutomirski
2018-01-11 1:47 ` Andi Kleen
2018-01-11 18:44 ` Andi Kleen
2018-01-11 2:09 ` Josh Poimboeuf
2018-01-12 3:22 ` Josh Poimboeuf
2018-01-10 1:03 ` [PATCH v1 2/8] x86/entry/clearregs: Add infrastructure to clear registers Andi Kleen
2018-01-11 19:58 ` Konrad Rzeszutek Wilk
2018-01-11 20:10 ` Andi Kleen
2018-01-10 1:03 ` [PATCH v1 3/8] x86/entry/clearregs: Clear registers for 64bit SYSCALL Andi Kleen
2018-01-11 3:35 ` Brian Gerst
2018-01-11 18:47 ` Andi Kleen
2018-01-12 3:45 ` Josh Poimboeuf
2018-01-10 1:03 ` [PATCH v1 4/8] x86/entry/retpoline: Clear extra registers for compat syscalls Andi Kleen
2018-01-10 1:03 ` [PATCH v1 5/8] x86/entry/clearregs: Clear registers for 64bit exceptions/interrupts Andi Kleen
2018-01-10 1:23 ` Andy Lutomirski
2018-01-10 1:03 ` [PATCH v1 6/8] x86/entry/clearregs: Add number of arguments to syscall tables Andi Kleen
2018-01-10 1:26 ` Andy Lutomirski
2018-01-10 4:37 ` Andi Kleen [this message]
2018-01-10 20:05 ` Andy Lutomirski
2018-01-10 1:03 ` [PATCH v1 7/8] x86/entry/clearregs: Add 64bit stubs to clear unused arguments regs Andi Kleen
2018-01-10 1:03 ` [PATCH v1 8/8] x86/entry/clearregs: Clear registers for 32bit kernel Andi Kleen
2018-01-10 1:24 ` Andy Lutomirski
2018-01-10 1:16 ` x86/clearregs: Register sanitizing at kernel entry for speculation hygiene Andy Lutomirski
2018-01-10 1:34 ` Andi Kleen
2018-01-10 1:39 ` Andy Lutomirski
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