From patchwork Tue Oct 16 10:16:45 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 10643417 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E157814E2 for ; Tue, 16 Oct 2018 10:52:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CDDB72984A for ; Tue, 16 Oct 2018 10:52:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BF0982984D; Tue, 16 Oct 2018 10:52:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B00F72984A for ; Tue, 16 Oct 2018 10:52:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727013AbeJPSlv (ORCPT ); Tue, 16 Oct 2018 14:41:51 -0400 Received: from gateway22.websitewelcome.com ([192.185.46.194]:40251 "EHLO gateway22.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726581AbeJPSlv (ORCPT ); Tue, 16 Oct 2018 14:41:51 -0400 X-Greylist: delayed 1490 seconds by postgrey-1.27 at vger.kernel.org; Tue, 16 Oct 2018 14:41:50 EDT Received: from cm15.websitewelcome.com (cm15.websitewelcome.com [100.42.49.9]) by gateway22.websitewelcome.com (Postfix) with ESMTP id 909FA1BCDD for ; Tue, 16 Oct 2018 05:17:34 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id CMPCgDIEMtz4jCMPbgL4cL; Tue, 16 Oct 2018 05:17:33 -0500 X-Authority-Reason: nr=8 Received: from lfbn-1-466-13.w86-245.abo.wanadoo.fr ([86.245.173.13]:35640 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1gCMPA-000TlY-NM; Tue, 16 Oct 2018 05:16:49 -0500 Date: Tue, 16 Oct 2018 12:16:45 +0200 From: "Gustavo A. R. Silva" To: Felipe Balbi , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] usb: gadget: storage: Fix Spectre v1 vulnerability Message-ID: <20181016101645.GA24870@embeddedor.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 86.245.173.13 X-Source-L: No X-Exim-ID: 1gCMPA-000TlY-NM X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: lfbn-1-466-13.w86-245.abo.wanadoo.fr (embeddedor) [86.245.173.13]:35640 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 3 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva Acked-by: Felipe Balbi --- drivers/usb/gadget/function/f_mass_storage.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c index cb402e7a..043f97a 100644 --- a/drivers/usb/gadget/function/f_mass_storage.c +++ b/drivers/usb/gadget/function/f_mass_storage.c @@ -221,6 +221,8 @@ #include #include +#include + #include "configfs.h" @@ -3152,6 +3154,7 @@ static struct config_group *fsg_lun_make(struct config_group *group, 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]) {