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Message-ID: <87r3v350io.fsf@tassilo.jf.intel.com>
Date: Fri, 09 Jan 2015 09:25:51 -0800
From: Andi Kleen <andi@...stfloor.org>
To: "Michael Kerrisk \(man-pages\)" <mtk.manpages@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
"linux-mm\@kvack.org" <linux-mm@...ck.org>,
Dave Hansen <dave.hansen@...el.com>,
Qiaowei Ren <qiaowei.ren@...el.com>,
lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86, mpx: Ensure unused arguments of prctl() MPX requests are 0
"Michael Kerrisk (man-pages)" <mtk.manpages@...il.com> writes:
> From: Michael Kerrisk <mtk.manpages@...il.com>
>
> commit fe8c7f5cbf91124987106faa3bdf0c8b955c4cf7 added two new prctl()
> operations, PR_MPX_ENABLE_MANAGEMENT and PR_MPX_DISABLE_MANAGEMENT.
> However, no checks were included to ensure that unused arguments
> are zero, as is done in many existing prctl()s and as should be
> done for all new prctl()s. This patch adds the required checks.
This will break the existing gcc run time, which doesn't zero these
arguments.
-ANdi
>
> Signed-off-by: Michael Kerrisk <mtk.manpages@...il.com>
> ---
> kernel/sys.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/kernel/sys.c b/kernel/sys.c
> index a8c9f5a..ea9c881 100644
> --- a/kernel/sys.c
> +++ b/kernel/sys.c
> @@ -2210,9 +2210,13 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
> up_write(&me->mm->mmap_sem);
> break;
> case PR_MPX_ENABLE_MANAGEMENT:
> + if (arg2 || arg3 || arg4 || arg5)
> + return -EINVAL;
> error = MPX_ENABLE_MANAGEMENT(me);
> break;
> case PR_MPX_DISABLE_MANAGEMENT:
> + if (arg2 || arg3 || arg4 || arg5)
> + return -EINVAL;
> error = MPX_DISABLE_MANAGEMENT(me);
> break;
> default:
> --
> 1.9.3
--
ak@...ux.intel.com -- Speaking for myself only
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