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authorAlex Elder <aelder@sgi.com>2011-03-01 12:50:00 -0500
committerAlex Elder <aelder@sgi.com>2011-03-01 22:19:59 -0500
commiteeb2036b8a148629b762ae6d85cff0be8106f081 (patch)
treec5fca77c46f9493ed02621a1dcd3bb89367b3807
parent20ad9ea9becd34a3c16252ca9d815f2c74f8f30f (diff)
xfs: zero proper structure size for geometry calls
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>
-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 f5e2a19e0f8e..0ca0e3c024d7 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl.c
@@ -695,14 +695,19 @@ xfs_ioc_fsgeometry_v1(
695 xfs_mount_t *mp, 695 xfs_mount_t *mp,
696 void __user *arg) 696 void __user *arg)
697{ 697{
698 xfs_fsop_geom_v1_t fsgeo; 698 xfs_fsop_geom_t fsgeo;
699 int error; 699 int error;
700 700
701 error = xfs_fs_geometry(mp, (xfs_fsop_geom_t *)&fsgeo, 3); 701 error = xfs_fs_geometry(mp, &fsgeo, 3);
702 if (error) 702 if (error)
703 return -error; 703 return -error;
704 704
705 if (copy_to_user(arg, &fsgeo, sizeof(fsgeo))) 705 /*
706 * Caller should have passed an argument of type
707 * xfs_fsop_geom_v1_t. This is a proper subset of the
708 * xfs_fsop_geom_t that xfs_fs_geometry() fills in.
709 */
710 if (copy_to_user(arg, &fsgeo, sizeof(xfs_fsop_geom_v1_t)))
706 return -XFS_ERROR(EFAULT); 711 return -XFS_ERROR(EFAULT);
707 return 0; 712 return 0;
708} 713}