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authorAlex Elder <aelder@sgi.com>2011-03-01 17:50:00 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-14 16:53:56 -0700
commiteebefbf469324489da006b9e5f8a1418bd4dc77f (patch)
treefad56e42e6c825959168fe41ba02cadcf9940a24
parentbd378dd6df5ca43021a49f72441a6c14d9784bed (diff)
xfs: zero proper structure size for geometry calls
commit af24ee9ea8d532e16883251a6684dfa1be8eec29 upstream. Commit 493f3358cb289ccf716c5a14fa5bb52ab75943e5 added this call to xfs_fs_geometry() in order to avoid passing kernel stack data back to user space: + memset(geo, 0, sizeof(*geo)); Unfortunately, one of the callers of that function passes the address of a smaller data type, cast to fit the type that xfs_fs_geometry() requires. As a result, this can happen: 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 fixing that one caller to pass the right type and then copy out the subset it is interested in. Note: This patch is an alternative to one originally proposed by Eric Sandeen. Reported-by: Jeffrey Hundstad <jeffrey.hundstad@mnsu.edu> Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Tested-by: Jeffrey Hundstad <jeffrey.hundstad@mnsu.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/xfs/linux-2.6/xfs_ioctl.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
index 61496c61f063..942362fa9c7a 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl.c
@@ -697,14 +697,19 @@ xfs_ioc_fsgeometry_v1(
xfs_mount_t *mp,
void __user *arg)
{
- xfs_fsop_geom_v1_t fsgeo;
+ xfs_fsop_geom_t fsgeo;
int error;
- error = xfs_fs_geometry(mp, (xfs_fsop_geom_t *)&fsgeo, 3);
+ error = xfs_fs_geometry(mp, &fsgeo, 3);
if (error)
return -error;
- if (copy_to_user(arg, &fsgeo, sizeof(fsgeo)))
+ /*
+ * Caller should have passed an argument of type
+ * xfs_fsop_geom_v1_t. This is a proper subset of the
+ * xfs_fsop_geom_t that xfs_fs_geometry() fills in.
+ */
+ if (copy_to_user(arg, &fsgeo, sizeof(xfs_fsop_geom_v1_t)))
return -XFS_ERROR(EFAULT);
return 0;
}