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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 BBA02ECDE47 for ; Thu, 8 Nov 2018 22:01:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 779AF208E3 for ; Thu, 8 Nov 2018 22:01:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="vZspvF/l" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 779AF208E3 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 S1730901AbeKIHjF (ORCPT ); Fri, 9 Nov 2018 02:39:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:58646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728090AbeKIHjE (ORCPT ); Fri, 9 Nov 2018 02:39:04 -0500 Received: from localhost (unknown [208.72.13.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8560C20892; Thu, 8 Nov 2018 22:01:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541714495; bh=VX3Dp+J9sbgHcEF8ms/W+ZtwfY3Tt5eilorz0gib4fs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vZspvF/lgqViOAUeKAOdBJsAE7xuwKeKS8q/0ynxAioKWN+SU5usoZPbTyp3AqINA LihbOHL85o5KpooN2oOi+O30O2sX0rvWoeq+JYEqGMLmm7V5GzKpdVm2OzciJQjohV MY/SQ3bOQ0AdgO5Zz5x6s6ZNV1LKf0qd3RTtjjkI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" , Felipe Balbi Subject: [PATCH 4.4 109/114] usb: gadget: storage: Fix Spectre v1 vulnerability Date: Thu, 8 Nov 2018 13:52:04 -0800 Message-Id: <20181108215110.618226295@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181108215059.051093652@linuxfoundation.org> References: <20181108215059.051093652@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 4.4-stable 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 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva Acked-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_mass_storage.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/usb/gadget/function/f_mass_storage.c +++ b/drivers/usb/gadget/function/f_mass_storage.c @@ -220,6 +220,8 @@ #include #include +#include + #include "configfs.h" @@ -3260,6 +3262,7 @@ 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]) {