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From: Dan Rosenberg <drosenberg@vsecurity.com>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: Jeffrey Hundstad <jeffrey.hundstad@mnsu.edu>,
	Eugene Teo <eugeneteo@kernel.org>,
	xfs@oss.sgi.com
Subject: Re: [PATCH V2] xfs: zero proper structure size for geometry calls
Date: Tue, 01 Mar 2011 07:55:32 -0500	[thread overview]
Message-ID: <1298984132.32568.3.camel@dan> (raw)
In-Reply-To: <4D6C9958.2040607@sandeen.net>

On Tue, 2011-03-01 at 00:59 -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.

Thanks for catching this early, and sorry for the misstep.

Reviewed-by: Dan Rosenberg <drosenberg@vsecurity.com>

> 
> Reported-by: Jeffrey Hundstad <jeffrey.hundstad@mnsu.edu>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> V2: Use sizeof (variable) not sizeof (type)
> 
> diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
> index f5e2a19..871e5f0 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(fsgeo));
>  	error = xfs_fs_geometry(mp, (xfs_fsop_geom_t *)&fsgeo, 3);
>  	if (error)
>  		return -error;
> @@ -715,6 +716,7 @@ xfs_ioc_fsgeometry(
>  	xfs_fsop_geom_t		fsgeo;
>  	int			error;
>  
> +	memset(&fsgeo, 0, sizeof(fsgeo));
>  	error = xfs_fs_geometry(mp, &fsgeo, 4);
>  	if (error)
>  		return -error;
> diff --git a/fs/xfs/linux-2.6/xfs_ioctl32.c b/fs/xfs/linux-2.6/xfs_ioctl32.c
> index b3486df..f25d38e 100644
> --- a/fs/xfs/linux-2.6/xfs_ioctl32.c
> +++ b/fs/xfs/linux-2.6/xfs_ioctl32.c
> @@ -73,6 +73,7 @@ xfs_compat_ioc_fsgeometry_v1(
>  	xfs_fsop_geom_t		  fsgeo;
>  	int			  error;
>  
> +	memset(&fsgeo, 0, sizeof(fsgeo));
>  	error = xfs_fs_geometry(mp, &fsgeo, 3);
>  	if (error)
>  		return -error;
> diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> index 85668ef..cec89dd 100644
> --- a/fs/xfs/xfs_fsops.c
> +++ b/fs/xfs/xfs_fsops.c
> @@ -53,9 +53,6 @@ xfs_fs_geometry(
>  	xfs_fsop_geom_t		*geo,
>  	int			new_version)
>  {
> -
> -	memset(geo, 0, sizeof(*geo));
> -
>  	geo->blocksize = mp->m_sb.sb_blocksize;
>  	geo->rtextsize = mp->m_sb.sb_rextsize;
>  	geo->agblocks = mp->m_sb.sb_agblocks;


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  reply	other threads:[~2011-03-01 12:52 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
2011-03-01  3:01     ` Eric Sandeen
2011-03-01  6:59   ` [PATCH V2] " Eric Sandeen
2011-03-01 12:55     ` Dan Rosenberg [this message]
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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