From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933358AbdA0LBV (ORCPT ); Fri, 27 Jan 2017 06:01:21 -0500 Received: from mx2.suse.de ([195.135.220.15]:33407 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933336AbdA0LBR (ORCPT ); Fri, 27 Jan 2017 06:01:17 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Al Viro , Jiri Slaby Subject: [PATCH 3.12 066/235] sg_write()/bsg_write() is not fit to be called under KERNEL_DS Date: Fri, 27 Jan 2017 11:53:19 +0100 Message-Id: <7eb9e6472cbdd8e2df774ae91531c8959e21dbbc.1485514374.git.jslaby@suse.cz> X-Mailer: git-send-email 2.11.0 In-Reply-To: <5b46dc789ca2be4046e4e40a131858d386cac741.1485514374.git.jslaby@suse.cz> References: <5b46dc789ca2be4046e4e40a131858d386cac741.1485514374.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Al Viro 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- block/bsg.c | 3 +++ drivers/scsi/sg.c | 3 +++ 2 files changed, 6 insertions(+) diff --git a/block/bsg.c b/block/bsg.c index 420a5a9f1b23..76801e57f556 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -675,6 +675,9 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 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; diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 1f65e32db285..291791a9be8b 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -568,6 +568,9 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos) sg_io_hdr_t *hp; unsigned char cmnd[MAX_COMMAND_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, printk("sg_write: %s, count=%d\n", -- 2.11.0