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=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 A0294ECE563 for ; Mon, 17 Sep 2018 23:03:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 63B862146F for ; Mon, 17 Sep 2018 23:03:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 63B862146F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730592AbeIREcs (ORCPT ); Tue, 18 Sep 2018 00:32:48 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48810 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727202AbeIREcr (ORCPT ); Tue, 18 Sep 2018 00:32:47 -0400 Received: from localhost (li1825-44.members.linode.com [172.104.248.44]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 6F1DFC03; Mon, 17 Sep 2018 23:03:18 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jinbum Park , Jens Axboe , Sasha Levin Subject: [PATCH 4.14 069/126] pktcdvd: Fix possible Spectre-v1 for pkt_devs Date: Tue, 18 Sep 2018 00:41:57 +0200 Message-Id: <20180917211708.811442655@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180917211703.481236999@linuxfoundation.org> References: <20180917211703.481236999@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jinbum Park [ Upstream commit 55690c07b44a82cc3359ce0c233f4ba7d80ba145 ] User controls @dev_minor which to be used as index of pkt_devs. So, It can be exploited via Spectre-like attack. (speculative execution) This kind of attack leaks address of pkt_devs, [1] It leads an attacker to bypass security mechanism such as KASLR. So sanitize @dev_minor before using it to prevent attack. [1] https://github.com/jinb-park/linux-exploit/ tree/master/exploit-remaining-spectre-gadget/leak_pkt_devs.c Signed-off-by: Jinbum Park Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/block/pktcdvd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/block/pktcdvd.c +++ b/drivers/block/pktcdvd.c @@ -67,7 +67,7 @@ #include #include #include - +#include #include #define DRIVER_NAME "pktcdvd" @@ -2231,6 +2231,8 @@ static struct pktcdvd_device *pkt_find_d { if (dev_minor >= MAX_WRITERS) return NULL; + + dev_minor = array_index_nospec(dev_minor, MAX_WRITERS); return pkt_devs[dev_minor]; }