From: Johannes Weiner <hannes@cmpxchg.org>
To: Jann Horn <jann@thejh.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Vlastimil Babka <vbabka@suse.cz>,
Jerome Marchand <jmarchan@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] swapfile: fix memory corruption via malformed swapfile
Date: Fri, 4 Nov 2016 10:57:04 -0400 [thread overview]
Message-ID: <20161104145704.GB8825@cmpxchg.org> (raw)
In-Reply-To: <1477949533-2509-1-git-send-email-jann@thejh.net>
On Mon, Oct 31, 2016 at 10:32:13PM +0100, Jann Horn wrote:
> When root activates a swap partition whose header has the wrong endianness,
> nr_badpages elements of badpages are swabbed before nr_badpages has been
> checked, leading to a buffer overrun of up to 8GB.
>
> This normally is not a security issue because it can only be exploited by
> root (more specifically, a process with CAP_SYS_ADMIN or the ability to
> modify a swap file/partition), and such a process can already e.g. modify
> swapped-out memory of any other userspace process on the system.
>
> Testcase for reproducing the bug (must be run as root, should crash your
> kernel):
[...]
> Cc: stable@vger.kernel.org
> Signed-off-by: Jann Horn <jann@thejh.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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prev parent reply other threads:[~2016-11-04 14:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-31 21:32 Jann Horn
2016-10-31 22:36 ` Kees Cook
2016-11-01 9:10 ` Jerome Marchand
2016-11-04 14:57 ` Johannes Weiner [this message]
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