xfs: Fix bulkstat compat ioctls on x32 userspace.
authorNick Bowler <nbowler@draconx.ca>
Mon, 17 Dec 2018 17:35:27 +0000 (09:35 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 5 Dec 2019 14:37:33 +0000 (15:37 +0100)
commit1cc7f4c628d92275572683219ea5e34580bd83bd
tree6b353e8fd498c919742f2968ddb92ed309ec4297
parent05ec56052bb9f14986b3ff0b05518f2a91874c0f
xfs: Fix bulkstat compat ioctls on x32 userspace.

[ Upstream commit 7ca860e3c1a74ad6bd8949364073ef1044cad758 ]

The bulkstat family of ioctls are problematic on x32, because there is
a mixup of native 32-bit and 64-bit conventions.  The xfs_fsop_bulkreq
struct contains pointers and 32-bit integers so that matches the native
32-bit layout, and that means the ioctl implementation goes into the
regular compat path on x32.

However, the 'ubuffer' member of that struct in turn refers to either
struct xfs_inogrp or xfs_bstat (or an array of these).  On x32, those
structures match the native 64-bit layout.  The compat implementation
writes out the 32-bit version of these structures.  This is not the
expected format for x32 userspace, causing problems.

Fortunately the functions which actually output these xfs_inogrp and
xfs_bstat structures have an easy way to select which output format
is required, so we just need a little tweak to select the right format
on x32.

Signed-off-by: Nick Bowler <nbowler@draconx.ca>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
fs/xfs/xfs_ioctl32.c