From: Peter Zijlstra <peterz@infradead.org>
To: Kangjie Lu <kjlu@umn.edu>
Cc: pakki001@umn.edu, Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched: fix a potential double-fetch bug in sched_copy_attr
Date: Mon, 7 Jan 2019 18:11:01 +0100 [thread overview]
Message-ID: <20190107171101.GI14122@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20181225221648.70069-1-kjlu@umn.edu>
On Tue, Dec 25, 2018 at 04:16:47PM -0600, Kangjie Lu wrote:
> "uattr->size" is copied in from user space and checked. However, it is
> copied in again after the security check. A malicious user may race to
> change it. The fix checks if uattr->size is ever changed after the
> check.
>
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
> + /* Sanity check if size was changed in user space */
> + if (attr->size != size)
> + return -EINVAL;
> +
What perf_copy_attr() does (from whence we copied this code) is:
attr->size = size;
Would that not also fix things?
next prev parent reply other threads:[~2019-01-07 17:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-25 22:16 Kangjie Lu
2019-01-07 17:11 ` Peter Zijlstra [this message]
2019-01-09 7:45 ` [PATCH v2] " Kangjie Lu
2019-01-21 11:32 ` [tip:sched/core] sched/core: Fix a potential double-fetch bug in sched_copy_attr() tip-bot for Kangjie Lu
2019-01-27 11:04 ` Thomas Gleixner
2019-01-27 11:28 ` Ingo Molnar
2019-01-28 7:58 ` Peter Zijlstra
2019-01-28 13:15 ` Thomas Gleixner
2019-03-10 10:09 ` Thomas Gleixner
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