From: Dave Chinner <david@fromorbit.com>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: Jeffrey Hundstad <jeffrey.hundstad@mnsu.edu>,
Dan Rosenberg <drosenberg@vsecurity.com>,
Eugene Teo <eugeneteo@kernel.org>,
xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: zero proper structure size for geometry calls
Date: Tue, 1 Mar 2011 13:59:44 +1100 [thread overview]
Message-ID: <20110301025944.GG3087@dastard> (raw)
In-Reply-To: <4D6C4DEE.6020902@sandeen.net>
On Mon, Feb 28, 2011 at 07:37:50PM -0600, Eric Sandeen wrote:
> commit 493f3358cb289ccf716c5a14fa5bb52ab75943e5 added:
>
> + memset(geo, 0, sizeof(*geo));
>
> but unfortunately we're dealing with a cast pointer here, and
> the caller may actually have a smaller structure on the stack.
> Zeroing out more leads to stack corruption traps:
>
> Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: f87aca93
>
> Pid: 262, comm: xfs_fsr Not tainted 2.6.38-rc6-493f3358cb2+ #1
> Call Trace:
>
> [<c12991ac>] ? panic+0x50/0x150
> [<c102ed71>] ? __stack_chk_fail+0x10/0x18
> [<f87aca93>] ? xfs_ioc_fsgeometry_v1+0x56/0x5d [xfs]
>
> Fix this by zeroing out the structure in the callers, where we know
> the actual size.
>
> Reported-by: Jeffrey Hundstad <jeffrey.hundstad@mnsu.edu>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
>
> diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
> index f5e2a19..34e401f 100644
> --- a/fs/xfs/linux-2.6/xfs_ioctl.c
> +++ b/fs/xfs/linux-2.6/xfs_ioctl.c
> @@ -698,6 +698,7 @@ xfs_ioc_fsgeometry_v1(
> xfs_fsop_geom_v1_t fsgeo;
> int error;
>
> + memset(&fsgeo, 0, sizeof(xfs_fsop_geom_v1_t));
I'd prefer that sizeof(fsgeo) is used here. That means if the type
is changed, then memset doesn't need to be. Same for all the rest
of the memset calls.
Otherwise,
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2011-03-01 2:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-28 22:58 kernel panic - stack-protector: kernel stack is corrupted in: f87aca93 Jeffrey Hundstad
2011-03-01 0:00 ` Eric Sandeen
2011-03-01 1:03 ` Jeffrey Hundstad
2011-03-01 1:32 ` Eric Sandeen
2011-03-01 2:57 ` Dave Chinner
2011-03-01 1:37 ` [PATCH] xfs: zero proper structure size for geometry calls Eric Sandeen
2011-03-01 2:59 ` Dave Chinner [this message]
2011-03-01 3:01 ` Eric Sandeen
2011-03-01 6:59 ` [PATCH V2] " Eric Sandeen
2011-03-01 12:55 ` Dan Rosenberg
2011-03-01 15:36 ` Jeffrey Hundstad
2011-03-01 15:49 ` Eric Sandeen
2011-03-01 17:50 ` [PATCH, V3 (sort of)] " Alex Elder
2011-03-01 18:18 ` Eric Sandeen
2011-03-01 21:40 ` Jeffrey Hundstad
2011-03-02 0:02 ` Dave Chinner
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