From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Serge E. Hallyn" Subject: Re: [PATCH v2 06/10] utsns: Add a limit on the number of uts namespaces Date: Mon, 25 Jul 2016 18:09:28 -0500 Message-ID: <20160725230927.GD26841@mail.hallyn.com> References: <87d1m754jc.fsf@x220.int.ebiederm.org> <20160721164014.17534-1-ebiederm@xmission.com> <20160721164014.17534-6-ebiederm@xmission.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20160721164014.17534-6-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: "Eric W. Biederman" Cc: Kees Cook , netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux Containers , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andy Lutomirski , Seth Forshee , Nikolay Borisov , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jann Horn List-Id: containers.vger.kernel.org Quoting Eric W. Biederman (ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org): > Signed-off-by: "Eric W. Biederman" Acked-by: Serge Hallyn > --- > include/linux/user_namespace.h | 1 + > kernel/user_namespace.c | 1 + > kernel/utsname.c | 31 ++++++++++++++++++++++++++----- > 3 files changed, 28 insertions(+), 5 deletions(-) > > diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h > index 47733637741a..bed2506081fe 100644 > --- a/include/linux/user_namespace.h > +++ b/include/linux/user_namespace.h > @@ -25,6 +25,7 @@ struct uid_gid_map { /* 64 bytes -- 1 cache line */ > enum ucounts { > UCOUNT_USER_NAMESPACES, > UCOUNT_PID_NAMESPACES, > + UCOUNT_UTS_NAMESPACES, > UCOUNT_COUNTS, > }; > > diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c > index 02a03ead7afc..6b205c24e888 100644 > --- a/kernel/user_namespace.c > +++ b/kernel/user_namespace.c > @@ -78,6 +78,7 @@ static int count_max = COUNT_MAX; > static struct ctl_table userns_table[] = { > UCOUNT_ENTRY("max_user_namespaces"), > UCOUNT_ENTRY("max_pid_namespaces"), > + UCOUNT_ENTRY("max_uts_namespaces"), > { } > }; > #endif /* CONFIG_SYSCTL */ > diff --git a/kernel/utsname.c b/kernel/utsname.c > index 831ea7108232..4f13c0419d64 100644 > --- a/kernel/utsname.c > +++ b/kernel/utsname.c > @@ -17,6 +17,16 @@ > #include > #include > > +static bool inc_uts_namespaces(struct user_namespace *ns) > +{ > + return inc_ucount(ns, UCOUNT_UTS_NAMESPACES); > +} > + > +static void dec_uts_namespaces(struct user_namespace *ns) > +{ > + dec_ucount(ns, UCOUNT_UTS_NAMESPACES); > +} > + > static struct uts_namespace *create_uts_ns(void) > { > struct uts_namespace *uts_ns; > @@ -38,15 +48,18 @@ static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, > struct uts_namespace *ns; > int err; > > + err = -ENFILE; > + if (!inc_uts_namespaces(user_ns)) > + goto fail; > + > + err = -ENOMEM; > ns = create_uts_ns(); > if (!ns) > - return ERR_PTR(-ENOMEM); > + goto fail_dec; > > err = ns_alloc_inum(&ns->ns); > - if (err) { > - kfree(ns); > - return ERR_PTR(err); > - } > + if (err) > + goto fail_free; > > ns->ns.ops = &utsns_operations; > > @@ -55,6 +68,13 @@ static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, > ns->user_ns = get_user_ns(user_ns); > up_read(&uts_sem); > return ns; > + > +fail_free: > + kfree(ns); > +fail_dec: > + dec_uts_namespaces(user_ns); > +fail: > + return ERR_PTR(err); > } > > /* > @@ -85,6 +105,7 @@ void free_uts_ns(struct kref *kref) > struct uts_namespace *ns; > > ns = container_of(kref, struct uts_namespace, kref); > + dec_uts_namespaces(ns->user_ns); > put_user_ns(ns->user_ns); > ns_free_inum(&ns->ns); > kfree(ns); > -- > 2.8.3 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753520AbcGYXJp (ORCPT ); Mon, 25 Jul 2016 19:09:45 -0400 Received: from h2.hallyn.com ([78.46.35.8]:54366 "EHLO h2.hallyn.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753373AbcGYXJk (ORCPT ); Mon, 25 Jul 2016 19:09:40 -0400 Date: Mon, 25 Jul 2016 18:09:28 -0500 From: "Serge E. Hallyn" To: "Eric W. Biederman" Cc: Linux Containers , 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 Subject: Re: [PATCH v2 06/10] utsns: Add a limit on the number of uts namespaces Message-ID: <20160725230927.GD26841@mail.hallyn.com> References: <87d1m754jc.fsf@x220.int.ebiederm.org> <20160721164014.17534-1-ebiederm@xmission.com> <20160721164014.17534-6-ebiederm@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160721164014.17534-6-ebiederm@xmission.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Quoting Eric W. Biederman (ebiederm@xmission.com): > Signed-off-by: "Eric W. Biederman" Acked-by: Serge Hallyn > --- > include/linux/user_namespace.h | 1 + > kernel/user_namespace.c | 1 + > kernel/utsname.c | 31 ++++++++++++++++++++++++++----- > 3 files changed, 28 insertions(+), 5 deletions(-) > > diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h > index 47733637741a..bed2506081fe 100644 > --- a/include/linux/user_namespace.h > +++ b/include/linux/user_namespace.h > @@ -25,6 +25,7 @@ struct uid_gid_map { /* 64 bytes -- 1 cache line */ > enum ucounts { > UCOUNT_USER_NAMESPACES, > UCOUNT_PID_NAMESPACES, > + UCOUNT_UTS_NAMESPACES, > UCOUNT_COUNTS, > }; > > diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c > index 02a03ead7afc..6b205c24e888 100644 > --- a/kernel/user_namespace.c > +++ b/kernel/user_namespace.c > @@ -78,6 +78,7 @@ static int count_max = COUNT_MAX; > static struct ctl_table userns_table[] = { > UCOUNT_ENTRY("max_user_namespaces"), > UCOUNT_ENTRY("max_pid_namespaces"), > + UCOUNT_ENTRY("max_uts_namespaces"), > { } > }; > #endif /* CONFIG_SYSCTL */ > diff --git a/kernel/utsname.c b/kernel/utsname.c > index 831ea7108232..4f13c0419d64 100644 > --- a/kernel/utsname.c > +++ b/kernel/utsname.c > @@ -17,6 +17,16 @@ > #include > #include > > +static bool inc_uts_namespaces(struct user_namespace *ns) > +{ > + return inc_ucount(ns, UCOUNT_UTS_NAMESPACES); > +} > + > +static void dec_uts_namespaces(struct user_namespace *ns) > +{ > + dec_ucount(ns, UCOUNT_UTS_NAMESPACES); > +} > + > static struct uts_namespace *create_uts_ns(void) > { > struct uts_namespace *uts_ns; > @@ -38,15 +48,18 @@ static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, > struct uts_namespace *ns; > int err; > > + err = -ENFILE; > + if (!inc_uts_namespaces(user_ns)) > + goto fail; > + > + err = -ENOMEM; > ns = create_uts_ns(); > if (!ns) > - return ERR_PTR(-ENOMEM); > + goto fail_dec; > > err = ns_alloc_inum(&ns->ns); > - if (err) { > - kfree(ns); > - return ERR_PTR(err); > - } > + if (err) > + goto fail_free; > > ns->ns.ops = &utsns_operations; > > @@ -55,6 +68,13 @@ static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, > ns->user_ns = get_user_ns(user_ns); > up_read(&uts_sem); > return ns; > + > +fail_free: > + kfree(ns); > +fail_dec: > + dec_uts_namespaces(user_ns); > +fail: > + return ERR_PTR(err); > } > > /* > @@ -85,6 +105,7 @@ void free_uts_ns(struct kref *kref) > struct uts_namespace *ns; > > ns = container_of(kref, struct uts_namespace, kref); > + dec_uts_namespaces(ns->user_ns); > put_user_ns(ns->user_ns); > ns_free_inum(&ns->ns); > kfree(ns); > -- > 2.8.3