From patchwork Mon Feb 20 10:19:00 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 9582439 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 6C3D960578 for ; Mon, 20 Feb 2017 10:27:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5D74128365 for ; Mon, 20 Feb 2017 10:27:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5236128851; Mon, 20 Feb 2017 10:27:39 +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 0558E28842 for ; Mon, 20 Feb 2017 10:27:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752826AbdBTKZC (ORCPT ); Mon, 20 Feb 2017 05:25:02 -0500 Received: from mga14.intel.com ([192.55.52.115]:44999 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752015AbdBTKZA (ORCPT ); Mon, 20 Feb 2017 05:25:00 -0500 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Feb 2017 02:24:55 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,186,1484035200"; d="scan'208";a="935966703" Received: from elena-thinkpad-x230.fi.intel.com ([10.237.72.69]) by orsmga003.jf.intel.com with ESMTP; 20 Feb 2017 02:24:49 -0800 From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: cgroups@vger.kernel.org, linux-audit@redhat.com, linux-fsdevel@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk, tj@kernel.org, mingo@redhat.com, hannes@cmpxchg.org, lizefan@huawei.com, acme@kernel.org, alexander.shishkin@linux.intel.com, paul@paul-moore.com, eparis@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, luto@kernel.org, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 11/19] kernel: convert cgroup_namespace.count from atomic_t to refcount_t Date: Mon, 20 Feb 2017 12:19:00 +0200 Message-Id: <1487585948-6401-12-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1487585948-6401-1-git-send-email-elena.reshetova@intel.com> References: <1487585948-6401-1-git-send-email-elena.reshetova@intel.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 refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor --- include/linux/cgroup.h | 7 ++++--- kernel/cgroup/cgroup.c | 2 +- kernel/cgroup/namespace.c | 2 +- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index f6b43fb..4412979 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -22,6 +22,7 @@ #include #include #include +#include #include @@ -640,7 +641,7 @@ static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} #endif /* CONFIG_CGROUP_DATA */ struct cgroup_namespace { - atomic_t count; + refcount_t count; struct ns_common ns; struct user_namespace *user_ns; struct ucounts *ucounts; @@ -675,12 +676,12 @@ copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns, static inline void get_cgroup_ns(struct cgroup_namespace *ns) { if (ns) - atomic_inc(&ns->count); + refcount_inc(&ns->count); } static inline void put_cgroup_ns(struct cgroup_namespace *ns) { - if (ns && atomic_dec_and_test(&ns->count)) + if (ns && refcount_dec_and_test(&ns->count)) free_cgroup_ns(ns); } diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index ffcb310..5b94c79 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -188,7 +188,7 @@ static u16 have_canfork_callback __read_mostly; /* cgroup namespace for init task */ struct cgroup_namespace init_cgroup_ns = { - .count = { .counter = 2, }, + .count = REFCOUNT_INIT(2), .user_ns = &init_user_ns, .ns.ops = &cgroupns_operations, .ns.inum = PROC_CGROUP_INIT_INO, diff --git a/kernel/cgroup/namespace.c b/kernel/cgroup/namespace.c index cff7ea6..86e9bbe 100644 --- a/kernel/cgroup/namespace.c +++ b/kernel/cgroup/namespace.c @@ -31,7 +31,7 @@ static struct cgroup_namespace *alloc_cgroup_ns(void) kfree(new_ns); return ERR_PTR(ret); } - atomic_set(&new_ns->count, 1); + refcount_set(&new_ns->count, 1); new_ns->ns.ops = &cgroupns_operations; return new_ns; }