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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 47816C65BAF for ; Sun, 9 Dec 2018 22:20:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0EB5D2081F for ; Sun, 9 Dec 2018 22:20:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0EB5D2081F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk 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 S1727998AbeLIWUF (ORCPT ); Sun, 9 Dec 2018 17:20:05 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35424 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726553AbeLIVzZ (ORCPT ); Sun, 9 Dec 2018 16:55:25 -0500 Received: from pub.yeoldevic.com ([81.174.156.145] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gW72o-0002iq-29; Sun, 09 Dec 2018 21:55:22 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gW72l-0003gt-EG; Sun, 09 Dec 2018 21:55:19 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Gustavo A. R. Silva" , "Greg Kroah-Hartman" , "Felipe Balbi" Date: Sun, 09 Dec 2018 21:50:33 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 315/328] usb: gadget: storage: Fix Spectre v1 vulnerability In-Reply-To: X-SA-Exim-Connect-IP: 81.174.156.145 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.62-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "Gustavo A. R. Silva" commit 9ae24af3669111d418242caec8dd4ebd9ba26860 upstream. num can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/usb/gadget/function/f_mass_storage.c:3177 fsg_lun_make() warn: potential spectre issue 'fsg_opts->common->luns' [r] (local cap) Fix this by sanitizing num before using it to index fsg_opts->common->luns Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Signed-off-by: Gustavo A. R. Silva Acked-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/usb/gadget/f_mass_storage.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/usb/gadget/f_mass_storage.c +++ b/drivers/usb/gadget/f_mass_storage.c @@ -219,6 +219,8 @@ #include #include +#include + #include "gadget_chips.h" #include "configfs.h" @@ -3344,6 +3346,7 @@ static struct config_group *fsg_lun_make fsg_opts = to_fsg_opts(&group->cg_item); if (num >= FSG_MAX_LUNS) return ERR_PTR(-ERANGE); + num = array_index_nospec(num, FSG_MAX_LUNS); mutex_lock(&fsg_opts->lock); if (fsg_opts->refcnt || fsg_opts->common->luns[num]) {