X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fnsproxy.c;h=f74e6c00e26d1f50fb1c404b2a6e5505354882bf;hb=ab3c68ee5fd329ba48094d3417fd60e30ea14a87;hp=ac99837e7a04c53304a46f72ac57f13d4e3a855d;hpb=858d72ead4864da0fb0b89b919524125ce998e27;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ac99837..f74e6c0 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -13,45 +13,39 @@
  *             Pavel Emelianov <xemul@openvz.org>
  */
 
+#include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/version.h>
 #include <linux/nsproxy.h>
 #include <linux/init_task.h>
 #include <linux/mnt_namespace.h>
 #include <linux/utsname.h>
 #include <linux/pid_namespace.h>
 #include <net/net_namespace.h>
+#include <linux/ipc_namespace.h>
 
 static struct kmem_cache *nsproxy_cachep;
 
-struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
-
-static inline void get_nsproxy(struct nsproxy *ns)
-{
-	atomic_inc(&ns->count);
-}
-
-void get_task_namespaces(struct task_struct *tsk)
-{
-	struct nsproxy *ns = tsk->nsproxy;
-	if (ns) {
-		get_nsproxy(ns);
-	}
-}
-
-/*
- * creates a copy of "orig" with refcount 1.
- */
-static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
+struct nsproxy init_nsproxy = {
+	.count	= ATOMIC_INIT(1),
+	.uts_ns	= &init_uts_ns,
+#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
+	.ipc_ns	= &init_ipc_ns,
+#endif
+	.mnt_ns	= NULL,
+	.pid_ns	= &init_pid_ns,
+#ifdef CONFIG_NET
+	.net_ns	= &init_net,
+#endif
+};
+
+static inline struct nsproxy *create_nsproxy(void)
 {
-	struct nsproxy *ns;
+	struct nsproxy *nsproxy;
 
-	ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
-	if (ns) {
-		memcpy(ns, orig, sizeof(struct nsproxy));
-		atomic_set(&ns->count, 1);
-	}
-	return ns;
+	nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
+	if (nsproxy)
+		atomic_set(&nsproxy->count, 1);
+	return nsproxy;
 }
 
 /*
@@ -65,7 +59,7 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 	struct nsproxy *new_nsp;
 	int err;
 
-	new_nsp = clone_nsproxy(tsk->nsproxy);
+	new_nsp = create_nsproxy();
 	if (!new_nsp)
 		return ERR_PTR(-ENOMEM);
 
@@ -87,18 +81,12 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_ipc;
 	}
 
-	new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
+	new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
 	if (IS_ERR(new_nsp->pid_ns)) {
 		err = PTR_ERR(new_nsp->pid_ns);
 		goto out_pid;
 	}
 
-	new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns);
-	if (IS_ERR(new_nsp->user_ns)) {
-		err = PTR_ERR(new_nsp->user_ns);
-		goto out_user;
-	}
-
 	new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns);
 	if (IS_ERR(new_nsp->net_ns)) {
 		err = PTR_ERR(new_nsp->net_ns);
@@ -108,9 +96,6 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 	return new_nsp;
 
 out_net:
-	if (new_nsp->user_ns)
-		put_user_ns(new_nsp->user_ns);
-out_user:
 	if (new_nsp->pid_ns)
 		put_pid_ns(new_nsp->pid_ns);
 out_pid:
@@ -142,7 +127,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
 
 	get_nsproxy(old_ns);
 
-	if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWUSER | CLONE_NEWNET)))
+	if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+				CLONE_NEWPID | CLONE_NEWNET)))
 		return 0;
 
 	if (!capable(CAP_SYS_ADMIN)) {
@@ -150,15 +136,21 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
 		goto out;
 	}
 
-	new_ns = create_new_namespaces(flags, tsk, tsk->fs);
-	if (IS_ERR(new_ns)) {
-		err = PTR_ERR(new_ns);
+	/*
+	 * CLONE_NEWIPC must detach from the undolist: after switching
+	 * to a new ipc namespace, the semaphore arrays from the old
+	 * namespace are unreachable.  In clone parlance, CLONE_SYSVSEM
+	 * means share undolist with parent, so we must forbid using
+	 * it along with CLONE_NEWIPC.
+	 */
+	if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) {
+		err = -EINVAL;
 		goto out;
 	}
 
-	err = ns_cgroup_clone(tsk);
-	if (err) {
-		put_nsproxy(new_ns);
+	new_ns = create_new_namespaces(flags, tsk, tsk->fs);
+	if (IS_ERR(new_ns)) {
+		err = PTR_ERR(new_ns);
 		goto out;
 	}
 
@@ -179,8 +171,6 @@ void free_nsproxy(struct nsproxy *ns)
 		put_ipc_ns(ns->ipc_ns);
 	if (ns->pid_ns)
 		put_pid_ns(ns->pid_ns);
-	if (ns->user_ns)
-		put_user_ns(ns->user_ns);
 	put_net(ns->net_ns);
 	kmem_cache_free(nsproxy_cachep, ns);
 }
@@ -195,7 +185,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
 	int err = 0;
 
 	if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
-			       CLONE_NEWUSER | CLONE_NEWNET)))
+			       CLONE_NEWNET)))
 		return 0;
 
 	if (!capable(CAP_SYS_ADMIN))
@@ -208,7 +198,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
 		goto out;
 	}
 
-	err = ns_cgroup_clone(current);
+	err = ns_cgroup_clone(current, task_pid(current));
 	if (err)
 		put_nsproxy(*new_nsp);
 
@@ -216,6 +206,33 @@ out:
 	return err;
 }
 
+void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
+{
+	struct nsproxy *ns;
+
+	might_sleep();
+
+	ns = p->nsproxy;
+
+	rcu_assign_pointer(p->nsproxy, new);
+
+	if (ns && atomic_dec_and_test(&ns->count)) {
+		/*
+		 * wait for others to get what they want from this nsproxy.
+		 *
+		 * cannot release this nsproxy via the call_rcu() since
+		 * put_mnt_ns() will want to sleep
+		 */
+		synchronize_rcu();
+		free_nsproxy(ns);
+	}
+}
+
+void exit_task_namespaces(struct task_struct *p)
+{
+	switch_task_namespaces(p, NULL);
+}
+
 static int __init nsproxy_cache_init(void)
 {
 	nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);