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From: Eric Sandeen <sandeen@sandeen.net>
To: Jeffrey Hundstad <jeffrey.hundstad@mnsu.edu>
Cc: Dan Rosenberg <drosenberg@vsecurity.com>,
	Eugene Teo <eugeneteo@kernel.org>,
	xfs@oss.sgi.com
Subject: [PATCH] xfs: zero proper structure size for geometry calls
Date: Mon, 28 Feb 2011 19:37:50 -0600	[thread overview]
Message-ID: <4D6C4DEE.6020902@sandeen.net> (raw)
In-Reply-To: <4D6C28A5.60905@mnsu.edu>

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));
 	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(xfs_fsop_geom_t));
 	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..de11e90 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(xfs_fsop_geom_t));
 	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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  parent reply	other threads:[~2011-03-01  1:35 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 ` Eric Sandeen [this message]
2011-03-01  2:59   ` [PATCH] xfs: zero proper structure size for geometry calls 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
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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