nsproxy: remove INIT_NSPROXY()

[safe/jmp/linux-2.6] / kernel / nsproxy.c

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ac99837..2ab6723 100644 (file)
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -14,44 +14,37 @@
  */
 
 #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 +58,7 @@ 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 +80,12 @@ 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 +95,6 @@ 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 +126,8 @@ 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 +135,21 @@ 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 +170,6 @@ 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 +184,7 @@ 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 +197,7 @@ 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 +205,33 @@ 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);