From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Darrick J. Wong" , Christoph Hellwig Subject: [PATCH 3.18 27/33] xfs: fix over-copying of getbmap parameters from userspace Date: Mon, 5 Jun 2017 18:17:20 +0200 Message-Id: <20170605153021.997256379@linuxfoundation.org> In-Reply-To: <20170605153020.953645204@linuxfoundation.org> References: <20170605153020.953645204@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Darrick J. Wong commit be6324c00c4d1e0e665f03ed1fc18863a88da119 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_ioctl.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/xfs/xfs_ioctl.c +++ b/fs/xfs/xfs_ioctl.c @@ -1378,10 +1378,11 @@ 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)