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 1890DECDE4B for ; Thu, 8 Nov 2018 22:07:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D33F620989 for ; Thu, 8 Nov 2018 22:07:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="cIQ4+2X4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D33F620989 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 S1732195AbeKIHod (ORCPT ); Fri, 9 Nov 2018 02:44:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:37414 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732130AbeKIHob (ORCPT ); Fri, 9 Nov 2018 02:44:31 -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 F038720844; Thu, 8 Nov 2018 22:06:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541714820; bh=hlrIAPWlMAMNorBW3KMrH58gmVzRw0IGzZkf2D93QjI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cIQ4+2X4U6pJTPOvaK1vt+3vuo11YTIIIuXli/GReQo857LIy/JnhjKOzsVi//mb9 lWhUNhX1uc/fPYZjnCRr213AyC1JE2Xq4SyjxoNYF6xhhpupcIcNINGUcZLNfjYi5Q jgrbhXpNylmWS1EHaChLvVMhqhju3ww0c2aHm0Xk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wenwen Wang , Michal Kubecek , "David S. Miller" Subject: [PATCH 4.9 147/171] ethtool: fix a privilege escalation bug Date: Thu, 8 Nov 2018 13:51:57 -0800 Message-Id: <20181108215137.545721852@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181108215127.257643509@linuxfoundation.org> References: <20181108215127.257643509@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 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wenwen Wang [ Upstream commit 58f5bbe331c566f49c9559568f982202a278aa78 ] In dev_ethtool(), the eth command 'ethcmd' is firstly copied from the use-space buffer 'useraddr' and checked to see whether it is ETHTOOL_PERQUEUE. If yes, the sub-command 'sub_cmd' is further copied from the user space. Otherwise, 'sub_cmd' is the same as 'ethcmd'. Next, according to 'sub_cmd', a permission check is enforced through the function ns_capable(). For example, the permission check is required if 'sub_cmd' is ETHTOOL_SCOALESCE, but it is not necessary if 'sub_cmd' is ETHTOOL_GCOALESCE, as suggested in the comment "Allow some commands to be done by anyone". The following execution invokes different handlers according to 'ethcmd'. Specifically, if 'ethcmd' is ETHTOOL_PERQUEUE, ethtool_set_per_queue() is called. In ethtool_set_per_queue(), the kernel object 'per_queue_opt' is copied again from the user-space buffer 'useraddr' and 'per_queue_opt.sub_command' is used to determine which operation should be performed. Given that the buffer 'useraddr' is in the user space, a malicious user can race to change the sub-command between the two copies. In particular, the attacker can supply ETHTOOL_PERQUEUE and ETHTOOL_GCOALESCE to bypass the permission check in dev_ethtool(). Then before ethtool_set_per_queue() is called, the attacker changes ETHTOOL_GCOALESCE to ETHTOOL_SCOALESCE. In this way, the attacker can bypass the permission check and execute ETHTOOL_SCOALESCE. This patch enforces a check in ethtool_set_per_queue() after the second copy from 'useraddr'. If the sub-command is different from the one obtained in the first copy in dev_ethtool(), an error code EINVAL will be returned. Fixes: f38d138a7da6 ("net/ethtool: support set coalesce per queue") Signed-off-by: Wenwen Wang Reviewed-by: Michal Kubecek Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/ethtool.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -2397,13 +2397,17 @@ roll_back: return ret; } -static int ethtool_set_per_queue(struct net_device *dev, void __user *useraddr) +static int ethtool_set_per_queue(struct net_device *dev, + void __user *useraddr, u32 sub_cmd) { struct ethtool_per_queue_op per_queue_opt; if (copy_from_user(&per_queue_opt, useraddr, sizeof(per_queue_opt))) return -EFAULT; + if (per_queue_opt.sub_command != sub_cmd) + return -EINVAL; + switch (per_queue_opt.sub_command) { case ETHTOOL_GCOALESCE: return ethtool_get_per_queue_coalesce(dev, useraddr, &per_queue_opt); @@ -2669,7 +2673,7 @@ int dev_ethtool(struct net *net, struct rc = ethtool_get_phy_stats(dev, useraddr); break; case ETHTOOL_PERQUEUE: - rc = ethtool_set_per_queue(dev, useraddr); + rc = ethtool_set_per_queue(dev, useraddr, sub_cmd); break; case ETHTOOL_GLINKSETTINGS: rc = ethtool_get_link_ksettings(dev, useraddr);