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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>

WARNING: multiple messages have this Message-ID (diff)
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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  parent reply	other threads:[~2016-11-04 14:57 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-31 21:32 [PATCH] swapfile: fix memory corruption via malformed swapfile Jann Horn
2016-10-31 21:32 ` Jann Horn
2016-10-31 22:36 ` Kees Cook
2016-10-31 22:36   ` Kees Cook
2016-11-01  9:10 ` Jerome Marchand
2016-11-04 14:57 ` Johannes Weiner [this message]
2016-11-04 14:57   ` Johannes Weiner

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