2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Alex Elder <[email protected]> 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 <[email protected]> Signed-off-by: Alex Elder <[email protected]> Signed-off-by: Andi Kleen <[email protected]> Reviewed-by: Eric Sandeen <[email protected]> Tested-by: Jeffrey Hundstad <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/xfs/linux-2.6/xfs_ioctl.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) Index: linux-2.6.35.y/fs/xfs/linux-2.6/xfs_ioctl.c =================================================================== --- linux-2.6.35.y.orig/fs/xfs/linux-2.6/xfs_ioctl.c +++ linux-2.6.35.y/fs/xfs/linux-2.6/xfs_ioctl.c @@ -703,14 +703,19 @@ 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; } _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
