From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Eric W. Biederman" Subject: [PATCH 07/10] ipcns: Add a limit on the number of ipc namespaces Date: Tue, 19 Jul 2016 20:21:35 -0500 Message-ID: <20160720012138.7894-7-ebiederm@xmission.com> References: <8737n5dscy.fsf@x220.int.ebiederm.org> <20160720012138.7894-1-ebiederm@xmission.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160720012138.7894-1-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: Linux Containers Cc: Kees Cook , Andy Lutomirski , Seth Forshee , Nikolay Borisov , "Eric W. Biederman" , Jann Horn List-Id: containers.vger.kernel.org Signed-off-by: "Eric W. Biederman" --- include/linux/user_namespace.h | 1 + ipc/namespace.c | 42 +++++++++++++++++++++++++++++++----------- kernel/user_namespace.c | 1 + 3 files changed, 33 insertions(+), 11 deletions(-) diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 10bb012a71d7..19f9ee590062 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -26,6 +26,7 @@ enum ucounts { UCOUNT_USER_NAMESPACES, UCOUNT_PID_NAMESPACES, UCOUNT_UTS_NAMESPACES, + UCOUNT_IPC_NAMESPACES, UCOUNT_MAX, }; diff --git a/ipc/namespace.c b/ipc/namespace.c index 04cb07eb81f1..3996a1e41a1d 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -16,33 +16,42 @@ #include "util.h" +static bool inc_ipc_namespaces(struct user_namespace *ns) +{ + return inc_ucount(ns, UCOUNT_IPC_NAMESPACES); +} + +static void dec_ipc_namespaces(struct user_namespace *ns) +{ + dec_ucount(ns, UCOUNT_IPC_NAMESPACES); +} + static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, struct ipc_namespace *old_ns) { struct ipc_namespace *ns; int err; + err = -ENFILE; + if (!inc_ipc_namespaces(user_ns)) + goto fail; + + err = -ENOMEM; ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); if (ns == NULL) - 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 = &ipcns_operations; atomic_set(&ns->count, 1); ns->user_ns = get_user_ns(user_ns); err = mq_init_ns(ns); - if (err) { - put_user_ns(ns->user_ns); - ns_free_inum(&ns->ns); - kfree(ns); - return ERR_PTR(err); - } + if (err) + goto fail_put; atomic_inc(&nr_ipc_ns); sem_init_ns(ns); @@ -50,6 +59,16 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, shm_init_ns(ns); return ns; + +fail_put: + put_user_ns(ns->user_ns); + ns_free_inum(&ns->ns); +fail_free: + kfree(ns); +fail_dec: + dec_ipc_namespaces(user_ns); +fail: + return ERR_PTR(err); } struct ipc_namespace *copy_ipcs(unsigned long flags, @@ -98,6 +117,7 @@ static void free_ipc_ns(struct ipc_namespace *ns) shm_exit_ns(ns); atomic_dec(&nr_ipc_ns); + dec_ipc_namespaces(ns->user_ns); put_user_ns(ns->user_ns); ns_free_inum(&ns->ns); kfree(ns); diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 4e019620f297..8c3a6e351b3e 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -79,6 +79,7 @@ static struct ctl_table userns_table[] = { UCOUNT_ENTRY("max_user_namespaces"), UCOUNT_ENTRY("max_pid_namespaces"), UCOUNT_ENTRY("max_uts_namespaces"), + UCOUNT_ENTRY("max_ipc_namespaces"), { } }; #endif /* CONFIG_SYSCTL */ -- 2.8.3