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=-7.1 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=unavailable 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 49552C433DF for ; Sat, 27 Jun 2020 13:23:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22D48208B6 for ; Sat, 27 Jun 2020 13:23:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Z1+JGGet" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726937AbgF0NXp (ORCPT ); Sat, 27 Jun 2020 09:23:45 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:35938 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726916AbgF0NXh (ORCPT ); Sat, 27 Jun 2020 09:23:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593264215; 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=k1ut6WkTgl4dIR6Pt+/0ewyvawbqPYzltO79GX8YVNI=; b=Z1+JGGetd0GVmefPiioE1H/5dnnX41I3qhURfAcLV5B5fdkMNxEG7DOOvjQ3/215Tt8BAS iJZFaJkTVqfhYicNZTDYKibFtRczC3jvI5APUr/PaE5YOJ9vKnMZ7lbKq+KBoEHw4++OPq gw74Ifa6fvDRLbl6BboOduEUAqV3VBw= 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-167-mnILldnlMISyoZ0KY_i4pg-1; Sat, 27 Jun 2020 09:23:31 -0400 X-MC-Unique: mnILldnlMISyoZ0KY_i4pg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9793618A0724; Sat, 27 Jun 2020 13:23:29 +0000 (UTC) Received: from madcap2.tricolour.ca (unknown [10.10.110.28]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8AE2C71662; Sat, 27 Jun 2020 13:23:19 +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 V9 11/13] audit: contid check descendancy and nesting Date: Sat, 27 Jun 2020 09:20:44 -0400 Message-Id: <01229b93733d9baf6ac9bb0cc243eeb08ad579cd.1593198710.git.rgb@redhat.com> In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@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 | 23 +++++++++++++++++++++-- kernel/sched/core.c | 33 +++++++++++++++++++++++++++++++++ security/yama/yama_lsm.c | 33 --------------------------------- 4 files changed, 57 insertions(+), 35 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 2213ac670386..06938d0b9e0c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2047,4 +2047,7 @@ 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 a862721dfd9b..efa65ec01239 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -2713,6 +2713,20 @@ int audit_signal_info(int sig, struct task_struct *t) return audit_signal_info_syscall(t); } +static bool audit_contid_isnesting(struct task_struct *tsk) +{ + bool isowner = false; + bool ownerisparent = false; + + rcu_read_lock(); + if (tsk->audit && tsk->audit->cont) { + isowner = current == tsk->audit->cont->owner; + ownerisparent = task_is_descendant(tsk->audit->cont->owner, current); + } + rcu_read_unlock(); + return !isowner && ownerisparent; +} + /* * audit_set_contid - set current task's audit contid * @task: target task @@ -2755,8 +2769,13 @@ int audit_set_contid(struct task_struct *task, u64 contid) rc = -EBUSY; goto unlock; } - /* if contid is already set, deny */ - if (audit_contid_set(task)) + /* if task is not descendant, block */ + if (task == current || !task_is_descendant(current, task)) { + rc = -EXDEV; + goto unlock; + } + /* only allow contid setting again if nesting */ + if (audit_contid_set(task) && !audit_contid_isnesting(task)) rc = -EEXIST; unlock: read_unlock(&tasklist_lock); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8f360326861e..e6b24c52b3c3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8012,6 +8012,39 @@ 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 536c99646f6a..24939f765df5 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