From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755255Ab2AXAMA (ORCPT ); Mon, 23 Jan 2012 19:12:00 -0500 Received: from cantor2.suse.de ([195.135.220.15]:41991 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754924Ab2AWXpq (ORCPT ); Mon, 23 Jan 2012 18:45:46 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Mon Jan 23 15:42:02 2012 Message-Id: <20120123234202.200082801@clark.kroah.org> User-Agent: quilt/0.50-11.1 Date: Mon, 23 Jan 2012 15:40:52 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Artem Bityutskiy Subject: [06/27] UBI: fix use-after-free on error path In-Reply-To: <20120123234224.GA19510@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Artem Bityutskiy commit e57e0d8e818512047fe379157c3f77f1b9fabffb upstream. When we fail to erase a PEB, we free the corresponding erase entry object, but then re-schedule this object if the error code was something like -EAGAIN. Obviously, it is a bug to use the object after we have freed it. Reported-by: Emese Revfy Signed-off-by: Artem Bityutskiy Signed-off-by: Greg Kroah-Hartman --- drivers/mtd/ubi/wl.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -1036,7 +1036,6 @@ static int erase_worker(struct ubi_devic ubi_err("failed to erase PEB %d, error %d", pnum, err); kfree(wl_wrk); - kmem_cache_free(ubi_wl_entry_slab, e); if (err == -EINTR || err == -ENOMEM || err == -EAGAIN || err == -EBUSY) { @@ -1049,14 +1048,16 @@ static int erase_worker(struct ubi_devic goto out_ro; } return err; - } else if (err != -EIO) { + } + + kmem_cache_free(ubi_wl_entry_slab, e); + if (err != -EIO) /* * If this is not %-EIO, we have no idea what to do. Scheduling * this physical eraseblock for erasure again would cause * errors again and again. Well, lets switch to R/O mode. */ goto out_ro; - } /* It is %-EIO, the PEB went bad */