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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 3579EC5CFC0 for ; Mon, 18 Jun 2018 08:31:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F060B20864 for ; Mon, 18 Jun 2018 08:31:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F060B20864 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 S967056AbeFRIbE (ORCPT ); Mon, 18 Jun 2018 04:31:04 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33872 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966813AbeFRIbB (ORCPT ); Mon, 18 Jun 2018 04:31:01 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id CEFE6C87; Mon, 18 Jun 2018 08:31:00 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexey Dobriyan , "Eric W. Biederman" , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 4.14 046/189] proc: revalidate kernel thread inodes to root:root Date: Mon, 18 Jun 2018 10:12:22 +0200 Message-Id: <20180618081211.193806618@linuxfoundation.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180618081209.254234434@linuxfoundation.org> References: <20180618081209.254234434@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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: Alexey Dobriyan [ Upstream commit 2e0ad552f5f8cd0fda02bc45fcd2b89821c62fd1 ] task_dump_owner() has the following code: mm = task->mm; if (mm) { if (get_dumpable(mm) != SUID_DUMP_USER) { uid = ... } } Check for ->mm is buggy -- kernel thread might be borrowing mm and inode will go to some random uid:gid pair. Link: http://lkml.kernel.org/r/20180412220109.GA20978@avx2 Signed-off-by: Alexey Dobriyan Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/proc/base.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1694,6 +1694,12 @@ void task_dump_owner(struct task_struct kuid_t uid; kgid_t gid; + if (unlikely(task->flags & PF_KTHREAD)) { + *ruid = GLOBAL_ROOT_UID; + *rgid = GLOBAL_ROOT_GID; + return; + } + /* Default to the tasks effective ownership */ rcu_read_lock(); cred = __task_cred(task);