From patchwork Thu Jul 21 16:40:09 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Eric W. Biederman" X-Patchwork-Id: 9242001 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2EFBF60574 for ; Thu, 21 Jul 2016 16:57:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 169A827F86 for ; Thu, 21 Jul 2016 16:57:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 06A3A1FF27; Thu, 21 Jul 2016 16:57:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 641671FF27 for ; Thu, 21 Jul 2016 16:57:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753663AbcGUQyC (ORCPT ); Thu, 21 Jul 2016 12:54:02 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:49750 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753483AbcGUQxz (ORCPT ); Thu, 21 Jul 2016 12:53:55 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1bQHEP-00060c-FP; Thu, 21 Jul 2016 10:53:53 -0600 Received: from 67-3-204-119.omah.qwest.net ([67.3.204.119] helo=x220.int.ebiederm.org) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1bQHEO-0000M2-Eb; Thu, 21 Jul 2016 10:53:53 -0600 From: "Eric W. Biederman" To: Linux Containers Cc: Andy Lutomirski , Jann Horn , Kees Cook , Nikolay Borisov , "Serge E. Hallyn" , Seth Forshee , linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, "Eric W. Biederman" Date: Thu, 21 Jul 2016 11:40:09 -0500 Message-Id: <20160721164014.17534-5-ebiederm@xmission.com> X-Mailer: git-send-email 2.8.3 In-Reply-To: <20160721164014.17534-1-ebiederm@xmission.com> References: <87d1m754jc.fsf@x220.int.ebiederm.org> <20160721164014.17534-1-ebiederm@xmission.com> X-XM-SPF: eid=1bQHEO-0000M2-Eb; ; ; mid=<20160721164014.17534-5-ebiederm@xmission.com>; ; ; hst=in02.mta.xmission.com; ; ; ip=67.3.204.119; ; ; frm=ebiederm@xmission.com; ; ; spf=neutral X-XM-AID: U2FsdGVkX19bzy8sybx1pk4Er5j5f0sg1a+hMYoBgaE= X-SA-Exim-Connect-IP: 67.3.204.119 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH v2 05/10] pidns: Add a limit on the number of pid namespaces X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Signed-off-by: "Eric W. Biederman" Acked-by: Serge Hallyn --- include/linux/user_namespace.h | 1 + kernel/pid_namespace.c | 22 ++++++++++++++++++---- kernel/user_namespace.c | 1 + 3 files changed, 20 insertions(+), 4 deletions(-) diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index f74a0facc696..47733637741a 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -24,6 +24,7 @@ struct uid_gid_map { /* 64 bytes -- 1 cache line */ enum ucounts { UCOUNT_USER_NAMESPACES, + UCOUNT_PID_NAMESPACES, UCOUNT_COUNTS, }; diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index a65ba137fd15..049cc14ae37a 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -79,6 +79,16 @@ static void proc_cleanup_work(struct work_struct *work) /* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */ #define MAX_PID_NS_LEVEL 32 +static bool inc_pid_namespaces(struct user_namespace *ns) +{ + return inc_ucount(ns, UCOUNT_PID_NAMESPACES); +} + +static void dec_pid_namespaces(struct user_namespace *ns) +{ + dec_ucount(ns, UCOUNT_PID_NAMESPACES); +} + static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns, struct pid_namespace *parent_pid_ns) { @@ -87,15 +97,16 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns int i; int err; - if (level > MAX_PID_NS_LEVEL) { - err = -EINVAL; + err = -EINVAL; + if (level > MAX_PID_NS_LEVEL) + goto out; + if (!inc_pid_namespaces(user_ns)) goto out; - } err = -ENOMEM; ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL); if (ns == NULL) - goto out; + goto out_dec; ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL); if (!ns->pidmap[0].page) @@ -129,6 +140,8 @@ out_free_map: kfree(ns->pidmap[0].page); out_free: kmem_cache_free(pid_ns_cachep, ns); +out_dec: + dec_pid_namespaces(user_ns); out: return ERR_PTR(err); } @@ -146,6 +159,7 @@ static void destroy_pid_namespace(struct pid_namespace *ns) ns_free_inum(&ns->ns); for (i = 0; i < PIDMAP_ENTRIES; i++) kfree(ns->pidmap[i].page); + dec_pid_namespaces(ns->user_ns); put_user_ns(ns->user_ns); call_rcu(&ns->rcu, delayed_free_pidns); } diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 728d7e4995ff..02a03ead7afc 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -77,6 +77,7 @@ static int count_max = COUNT_MAX; } static struct ctl_table userns_table[] = { UCOUNT_ENTRY("max_user_namespaces"), + UCOUNT_ENTRY("max_pid_namespaces"), { } }; #endif /* CONFIG_SYSCTL */