1 files changed, 92 insertions, 36 deletions

diff --git a/ipc/namespace.c b/ipc/namespace.c
index 4a5e752a927..59451c1e214 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -11,10 +11,13 @@
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/mount.h>
+#include <linux/user_namespace.h>
+#include <linux/proc_ns.h>
 
 #include "util.h"
 
-static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
+static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
+					   struct ipc_namespace *old_ns)
 {
 	struct ipc_namespace *ns;
 	int err;
@@ -23,9 +26,16 @@ static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
 	if (ns == NULL)
 		return ERR_PTR(-ENOMEM);
 
+	err = proc_alloc_inum(&ns->proc_inum);
+	if (err) {
+		kfree(ns);
+		return ERR_PTR(err);
+	}
+
 	atomic_set(&ns->count, 1);
 	err = mq_init_ns(ns);
 	if (err) {
+		proc_free_inum(ns->proc_inum);
 		kfree(ns);
 		return ERR_PTR(err);
 	}
@@ -43,23 +53,17 @@ static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
 	ipcns_notify(IPCNS_CREATED);
 	register_ipcns_notifier(ns);
 
+	ns->user_ns = get_user_ns(user_ns);
+
 	return ns;
 }
 
-struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
+struct ipc_namespace *copy_ipcs(unsigned long flags,
+	struct user_namespace *user_ns, struct ipc_namespace *ns)
 {
-	struct ipc_namespace *new_ns;
-
-	BUG_ON(!ns);
-	get_ipc_ns(ns);
-
 	if (!(flags & CLONE_NEWIPC))
-		return ns;
-
-	new_ns = clone_ipc_ns(ns);
-
-	put_ipc_ns(ns);
-	return new_ns;
+		return get_ipc_ns(ns);
+	return create_ipc_ns(user_ns, ns);
 }
 
 /*
@@ -77,7 +81,7 @@ void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
 	int next_id;
 	int total, in_use;
 
-	down_write(&ids->rw_mutex);
+	down_write(&ids->rwsem);
 
 	in_use = ids->in_use;
 
@@ -85,11 +89,38 @@ void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
 		perm = idr_find(&ids->ipcs_idr, next_id);
 		if (perm == NULL)
 			continue;
-		ipc_lock_by_ptr(perm);
+		rcu_read_lock();
+		ipc_lock_object(perm);
 		free(ns, perm);
 		total++;
 	}
-	up_write(&ids->rw_mutex);
+	up_write(&ids->rwsem);
+}
+
+static void free_ipc_ns(struct ipc_namespace *ns)
+{
+	/*
+	 * Unregistering the hotplug notifier at the beginning guarantees
+	 * that the ipc namespace won't be freed while we are inside the
+	 * callback routine. Since the blocking_notifier_chain_XXX routines
+	 * hold a rw lock on the notifier list, unregister_ipcns_notifier()
+	 * won't take the rw lock before blocking_notifier_call_chain() has
+	 * released the rd lock.
+	 */
+	unregister_ipcns_notifier(ns);
+	sem_exit_ns(ns);
+	msg_exit_ns(ns);
+	shm_exit_ns(ns);
+	atomic_dec(&nr_ipc_ns);
+
+	/*
+	 * Do the ipcns removal notification after decrementing nr_ipc_ns in
+	 * order to have a correct value when recomputing msgmni.
+	 */
+	ipcns_notify(IPCNS_REMOVED);
+	put_user_ns(ns->user_ns);
+	proc_free_inum(ns->proc_inum);
+	kfree(ns);
 }
 
 /*
@@ -118,26 +149,51 @@ void put_ipc_ns(struct ipc_namespace *ns)
 	}
 }
 
-void free_ipc_ns(struct ipc_namespace *ns)
+static void *ipcns_get(struct task_struct *task)
 {
-	/*
-	 * Unregistering the hotplug notifier at the beginning guarantees
-	 * that the ipc namespace won't be freed while we are inside the
-	 * callback routine. Since the blocking_notifier_chain_XXX routines
-	 * hold a rw lock on the notifier list, unregister_ipcns_notifier()
-	 * won't take the rw lock before blocking_notifier_call_chain() has
-	 * released the rd lock.
-	 */
-	unregister_ipcns_notifier(ns);
-	sem_exit_ns(ns);
-	msg_exit_ns(ns);
-	shm_exit_ns(ns);
-	kfree(ns);
-	atomic_dec(&nr_ipc_ns);
+	struct ipc_namespace *ns = NULL;
+	struct nsproxy *nsproxy;
 
-	/*
-	 * Do the ipcns removal notification after decrementing nr_ipc_ns in
-	 * order to have a correct value when recomputing msgmni.
-	 */
-	ipcns_notify(IPCNS_REMOVED);
+	rcu_read_lock();
+	nsproxy = task_nsproxy(task);
+	if (nsproxy)
+		ns = get_ipc_ns(nsproxy->ipc_ns);
+	rcu_read_unlock();
+
+	return ns;
+}
+
+static void ipcns_put(void *ns)
+{
+	return put_ipc_ns(ns);
 }
+
+static int ipcns_install(struct nsproxy *nsproxy, void *new)
+{
+	struct ipc_namespace *ns = new;
+	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
+	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
+		return -EPERM;
+
+	/* Ditch state from the old ipc namespace */
+	exit_sem(current);
+	put_ipc_ns(nsproxy->ipc_ns);
+	nsproxy->ipc_ns = get_ipc_ns(ns);
+	return 0;
+}
+
+static unsigned int ipcns_inum(void *vp)
+{
+	struct ipc_namespace *ns = vp;
+
+	return ns->proc_inum;
+}
+
+const struct proc_ns_operations ipcns_operations = {
+	.name		= "ipc",
+	.type		= CLONE_NEWIPC,
+	.get		= ipcns_get,
+	.put		= ipcns_put,
+	.install	= ipcns_install,
+	.inum		= ipcns_inum,
+};