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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 B8B1CC2D0DE for ; Tue, 31 Dec 2019 19:51:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 883BF206E0 for ; Tue, 31 Dec 2019 19:51:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NOyl7Pju" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727473AbfLaTvU (ORCPT ); Tue, 31 Dec 2019 14:51:20 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:56113 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727467AbfLaTvT (ORCPT ); Tue, 31 Dec 2019 14:51:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1577821878; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:in-reply-to: references:references:references; bh=gaH4dd8Z+XL1O+VprrUW8qEQbUr1BMF6sh27hxR0C7U=; b=NOyl7PjuSZAAF0xemPN6iS6/r6ZSyyx/t42Ks9sMai1VgARqqU17lZVsx8KEyVAlaNtpnk fHU63eRU01kimsXdKfIbOXpCL/GTjruI/y6ELw0tpG/wpa68xqE8JVwO0aSXfaG5XHIbRI t59gnHHqFDrMYqpvi8dG7g7s4tEYlGI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-300-yrJK3mD1OvezzYVY8b7Lqw-1; Tue, 31 Dec 2019 14:51:16 -0500 X-MC-Unique: yrJK3mD1OvezzYVY8b7Lqw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 32AF510054E3; Tue, 31 Dec 2019 19:51:13 +0000 (UTC) Received: from madcap2.tricolour.ca (ovpn-112-15.phx2.redhat.com [10.3.112.15]) by smtp.corp.redhat.com (Postfix) with ESMTP id A15B18208E; Tue, 31 Dec 2019 19:51:08 +0000 (UTC) From: Richard Guy Briggs To: containers@lists.linux-foundation.org, linux-api@vger.kernel.org, Linux-Audit Mailing List , linux-fsdevel@vger.kernel.org, LKML , netdev@vger.kernel.org, netfilter-devel@vger.kernel.org Cc: Paul Moore , sgrubb@redhat.com, omosnace@redhat.com, dhowells@redhat.com, simo@redhat.com, eparis@parisplace.org, serge@hallyn.com, ebiederm@xmission.com, nhorman@tuxdriver.com, dwalsh@redhat.com, mpatel@redhat.com, Richard Guy Briggs Subject: [PATCH ghak90 V8 12/16] audit: contid check descendancy and nesting Date: Tue, 31 Dec 2019 14:48:25 -0500 Message-Id: In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Require the target task to be a descendant of the container orchestrator/engine. You would only change the audit container ID from one set or inherited value to another if you were nesting containers. If changing the contid, the container orchestrator/engine must be a descendant and not same orchestrator as the one that set it so it is not possible to change the contid of another orchestrator's container. Since the task_is_descendant() function is used in YAMA and in audit, remove the duplication and pull the function into kernel/core/sched.c Signed-off-by: Richard Guy Briggs --- include/linux/sched.h | 3 +++ kernel/audit.c | 44 ++++++++++++++++++++++++++++++++++++-------- kernel/sched/core.c | 33 +++++++++++++++++++++++++++++++++ security/yama/yama_lsm.c | 33 --------------------------------- 4 files changed, 72 insertions(+), 41 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index aebe24192b23..009d2cb2e2bf 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2006,4 +2006,7 @@ static inline void rseq_syscall(struct pt_regs *regs) const struct cpumask *sched_trace_rd_span(struct root_domain *rd); +extern int task_is_descendant(struct task_struct *parent, + struct task_struct *child); + #endif diff --git a/kernel/audit.c b/kernel/audit.c index f7a8d3288ca0..ef8e07524c46 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -2575,6 +2575,13 @@ int audit_signal_info(int sig, struct task_struct *t) return audit_signal_info_syscall(t); } +static bool audit_contid_isowner(struct task_struct *tsk) +{ + if (tsk->audit && tsk->audit->cont) + return current == tsk->audit->cont->owner; + return false; +} + /* * audit_set_contid - set current task's audit contid * @task: target task @@ -2603,22 +2610,43 @@ int audit_set_contid(struct task_struct *task, u64 contid) oldcontid = audit_get_contid(task); read_lock(&tasklist_lock); /* Don't allow the contid to be unset */ - if (!audit_contid_valid(contid)) + if (!audit_contid_valid(contid)) { rc = -EINVAL; + goto unlock; + } /* Don't allow the contid to be set to the same value again */ - else if (contid == oldcontid) { + if (contid == oldcontid) { rc = -EADDRINUSE; + goto unlock; + } /* if we don't have caps, reject */ - else if (!capable(CAP_AUDIT_CONTROL)) + if (!capable(CAP_AUDIT_CONTROL)) { rc = -EPERM; - /* if task has children or is not single-threaded, deny */ - else if (!list_empty(&task->children)) + goto unlock; + } + /* if task has children, deny */ + if (!list_empty(&task->children)) { rc = -EBUSY; - else if (!(thread_group_leader(task) && thread_group_empty(task))) + goto unlock; + } + /* if task is not single-threaded, deny */ + if (!(thread_group_leader(task) && thread_group_empty(task))) { rc = -EALREADY; - /* if contid is already set, deny */ - else if (audit_contid_set(task)) + goto unlock; + } + /* if task is not descendant, block */ + if (task == current) { + rc = -EBADSLT; + goto unlock; + } + if (!task_is_descendant(current, task)) { + rc = -EXDEV; + goto unlock; + } + /* only allow contid setting again if nesting */ + if (audit_contid_set(task) && audit_contid_isowner(task)) rc = -ECHILD; +unlock: read_unlock(&tasklist_lock); if (!rc) { struct audit_contobj *oldcont = _audit_contobj(task); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 90e4b00ace89..7d8145285eb9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7916,6 +7916,39 @@ void dump_cpu_task(int cpu) } /* + * task_is_descendant - walk up a process family tree looking for a match + * @parent: the process to compare against while walking up from child + * @child: the process to start from while looking upwards for parent + * + * Returns 1 if child is a descendant of parent, 0 if not. + */ +int task_is_descendant(struct task_struct *parent, + struct task_struct *child) +{ + int rc = 0; + struct task_struct *walker = child; + + if (!parent || !child) + return 0; + + rcu_read_lock(); + if (!thread_group_leader(parent)) + parent = rcu_dereference(parent->group_leader); + while (walker->pid > 0) { + if (!thread_group_leader(walker)) + walker = rcu_dereference(walker->group_leader); + if (walker == parent) { + rc = 1; + break; + } + walker = rcu_dereference(walker->real_parent); + } + rcu_read_unlock(); + + return rc; +} + +/* * Nice levels are multiplicative, with a gentle 10% change for every * nice level changed. I.e. when a CPU-bound task goes from nice 0 to * nice 1, it will get ~10% less CPU time than another CPU-bound task diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c index 94dc346370b1..25eae205eae8 100644 --- a/security/yama/yama_lsm.c +++ b/security/yama/yama_lsm.c @@ -263,39 +263,6 @@ static int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3, } /** - * task_is_descendant - walk up a process family tree looking for a match - * @parent: the process to compare against while walking up from child - * @child: the process to start from while looking upwards for parent - * - * Returns 1 if child is a descendant of parent, 0 if not. - */ -static int task_is_descendant(struct task_struct *parent, - struct task_struct *child) -{ - int rc = 0; - struct task_struct *walker = child; - - if (!parent || !child) - return 0; - - rcu_read_lock(); - if (!thread_group_leader(parent)) - parent = rcu_dereference(parent->group_leader); - while (walker->pid > 0) { - if (!thread_group_leader(walker)) - walker = rcu_dereference(walker->group_leader); - if (walker == parent) { - rc = 1; - break; - } - walker = rcu_dereference(walker->real_parent); - } - rcu_read_unlock(); - - return rc; -} - -/** * ptracer_exception_found - tracer registered as exception for this tracee * @tracer: the task_struct of the process attempting ptrace * @tracee: the task_struct of the process to be ptraced -- 1.8.3.1