From be6324c00c4d1e0e665f03ed1fc18863a88da119 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 3 Apr 2017 15:17:57 -0700 Subject: xfs: fix over-copying of getbmap parameters from userspace In xfs_ioc_getbmap, we should only copy the fields of struct getbmap from userspace, or else we end up copying random stack contents into the kernel. struct getbmap is a strict subset of getbmapx, so a partial structure copy should work fine. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/xfs_ioctl.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'fs/xfs/xfs_ioctl.c') diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c index 2fd7fdf5438f..6d30b06e79bc 100644 --- a/fs/xfs/xfs_ioctl.c +++ b/fs/xfs/xfs_ioctl.c @@ -1543,10 +1543,11 @@ xfs_ioc_getbmap( unsigned int cmd, void __user *arg) { - struct getbmapx bmx; + struct getbmapx bmx = { 0 }; int error; - if (copy_from_user(&bmx, arg, sizeof(struct getbmapx))) + /* struct getbmap is a strict subset of struct getbmapx. */ + if (copy_from_user(&bmx, arg, offsetof(struct getbmapx, bmv_iflags))) return -EFAULT; if (bmx.bmv_count < 2) -- cgit v1.2.3