From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53066 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S939545AbdAFVxO (ORCPT ); Fri, 6 Jan 2017 16:53:14 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro Subject: [PATCH 4.8 90/96] sg_write()/bsg_write() is not fit to be called under KERNEL_DS Date: Fri, 6 Jan 2017 22:44:18 +0100 Message-Id: <20170106214231.396133510@linuxfoundation.org> In-Reply-To: <20170106214227.601120243@linuxfoundation.org> References: <20170106214227.601120243@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 128394eff343fc6d2f32172f03e24829539c5835 upstream. Both damn things interpret userland pointers embedded into the payload; worse, they are actually traversing those. Leaving aside the bad API design, this is very much _not_ safe to call with KERNEL_DS. Bail out early if that happens. Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- block/bsg.c | 3 +++ drivers/scsi/sg.c | 3 +++ 2 files changed, 6 insertions(+) --- a/block/bsg.c +++ b/block/bsg.c @@ -655,6 +655,9 @@ bsg_write(struct file *file, const char dprintk("%s: write %Zd bytes\n", bd->name, count); + if (unlikely(segment_eq(get_fs(), KERNEL_DS))) + return -EINVAL; + bsg_set_block(bd, file); bytes_written = 0; --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -592,6 +592,9 @@ sg_write(struct file *filp, const char _ sg_io_hdr_t *hp; unsigned char cmnd[SG_MAX_CDB_SIZE]; + if (unlikely(segment_eq(get_fs(), KERNEL_DS))) + return -EINVAL; + if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))) return -ENXIO; SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,