From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9DB6C282DA for ; Mon, 15 Apr 2019 11:12:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E31620848 for ; Mon, 15 Apr 2019 11:12:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727327AbfDOLMk (ORCPT ); Mon, 15 Apr 2019 07:12:40 -0400 Received: from mx2.suse.de ([195.135.220.15]:42172 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726298AbfDOLMj (ORCPT ); Mon, 15 Apr 2019 07:12:39 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 00DD0B05E; Mon, 15 Apr 2019 11:12:37 +0000 (UTC) Message-ID: <1555326745.13626.10.camel@suse.com> Subject: Re: KASAN: use-after-free Read in dvb_usb_device_exit From: Oliver Neukum To: syzbot , andreyknvl@google.com, syzkaller-bugs@googlegroups.com, mchehab@kernel.org, corbet@lwn.net, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-usb@vger.kernel.org Date: Mon, 15 Apr 2019 13:12:25 +0200 In-Reply-To: <000000000000789d3d058653d9bb@google.com> References: <000000000000789d3d058653d9bb@google.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fr, 2019-04-12 at 04:46 -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 9a33b369 usb-fuzzer: main usb gadget fuzzer driver > git tree: https://github.com/google/kasan/tree/usb-fuzzer > console output: https://syzkaller.appspot.com/x/log.txt?x=1643974b200000 > kernel config: https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15 > dashboard link: https://syzkaller.appspot.com/bug?extid=26ec41e9f788b3eba396 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12f5efa7200000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1395a0f3200000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+26ec41e9f788b3eba396@syzkaller.appspotmail.com > > dvb-usb: schedule remote query interval to 150 msecs. > dw2102: su3000_power_ctrl: 0, initialized 1 > dvb-usb: TeVii S421 PCI successfully initialized and connected. > usb 1-1: USB disconnect, device number 2 Hi, proposed fix. If nobody objects, I will submit it. Regards Oliver >From d6097d205ac61745334b79639d3b8b910ae66c71 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Mon, 15 Apr 2019 13:06:01 +0200 Subject: [PATCH] dvb: usb: fix use after free in dvb_usb_device_exit dvb_usb_device_exit() frees and uses teh device name in that order Fix by storing the name in a buffer before freeing it Signed-off-by: Oliver Neukum Reported-by: syzbot+26ec41e9f788b3eba396@syzkaller.appspotmail.com --- drivers/media/usb/dvb-usb/dvb-usb-init.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c index 99951e02a880..2e1670cc3903 100644 --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c @@ -288,13 +288,18 @@ void dvb_usb_device_exit(struct usb_interface *intf) { struct dvb_usb_device *d = usb_get_intfdata(intf); const char *name = "generic DVB-USB module"; + char identifier[40]; usb_set_intfdata(intf, NULL); if (d != NULL && d->desc != NULL) { name = d->desc->name; + memcpy(identifier, name, 39); + identifier[39] = NULL; dvb_usb_exit(d); + } else { + memcpy(identifier, name, 39); } - info("%s successfully deinitialized and disconnected.", name); + info("%s successfully deinitialized and disconnected.", identifier); } EXPORT_SYMBOL(dvb_usb_device_exit); -- 2.16.4