imported jens patch from

[powerpc.git] / kernel / nsproxy.c

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 674aceb..1bc4b55 100644 (file)
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -17,8 +17,9 @@
 #include <linux/version.h>
 #include <linux/nsproxy.h>
 #include <linux/init_task.h>
-#include <linux/namespace.h>
+#include <linux/mnt_namespace.h>
 #include <linux/utsname.h>
+#include <linux/pid_namespace.h>
 
 struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
 
@@ -37,10 +38,8 @@ void get_task_namespaces(struct task_struct *tsk)
 
 /*
  * creates a copy of "orig" with refcount 1.
- * This does not grab references to the contained namespaces,
- * so that needs to be done by dup_namespaces.
  */
-static inline struct nsproxy *clone_namespaces(struct nsproxy *orig)
+static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
 {
        struct nsproxy *ns;
 
@@ -51,24 +50,49 @@ static inline struct nsproxy *clone_namespaces(struct nsproxy *orig)
 }
 
 /*
- * copies the nsproxy, setting refcount to 1, and grabbing a
- * reference to all contained namespaces.  Called from
- * sys_unshare()
+ * Create new nsproxy and all of its the associated namespaces.
+ * Return the newly created nsproxy.  Do not attach this to the task,
+ * leave it to the caller to do proper locking and attach it to task.
  */
-struct nsproxy *dup_namespaces(struct nsproxy *orig)
+static struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk,
+                       struct fs_struct *new_fs)
 {
-       struct nsproxy *ns = clone_namespaces(orig);
+       struct nsproxy *new_nsp;
 
-       if (ns) {
-               if (ns->namespace)
-                       get_namespace(ns->namespace);
-               if (ns->uts_ns)
-                       get_uts_ns(ns->uts_ns);
-               if (ns->ipc_ns)
-                       get_ipc_ns(ns->ipc_ns);
-       }
+       new_nsp = clone_nsproxy(tsk->nsproxy);
+       if (!new_nsp)
+               return ERR_PTR(-ENOMEM);
 
-       return ns;
+       new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
+       if (IS_ERR(new_nsp->mnt_ns))
+               goto out_ns;
+
+       new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
+       if (IS_ERR(new_nsp->uts_ns))
+               goto out_uts;
+
+       new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
+       if (IS_ERR(new_nsp->ipc_ns))
+               goto out_ipc;
+
+       new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
+       if (IS_ERR(new_nsp->pid_ns))
+               goto out_pid;
+
+       return new_nsp;
+
+out_pid:
+       if (new_nsp->ipc_ns)
+               put_ipc_ns(new_nsp->ipc_ns);
+out_ipc:
+       if (new_nsp->uts_ns)
+               put_uts_ns(new_nsp->uts_ns);
+out_uts:
+       if (new_nsp->mnt_ns)
+               put_mnt_ns(new_nsp->mnt_ns);
+out_ns:
+       kfree(new_nsp);
+       return ERR_PTR(-ENOMEM);
 }
 
 /*
@@ -89,49 +113,70 @@ int copy_namespaces(int flags, struct task_struct *tsk)
        if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
                return 0;
 
-       new_ns = clone_namespaces(old_ns);
-       if (!new_ns) {
-               err = -ENOMEM;
+       if (!capable(CAP_SYS_ADMIN)) {
+               err = -EPERM;
                goto out;
        }
 
-       tsk->nsproxy = new_ns;
-
-       err = copy_namespace(flags, tsk);
-       if (err)
-               goto out_ns;
-
-       err = copy_utsname(flags, tsk);
-       if (err)
-               goto out_uts;
-
-       err = copy_ipcs(flags, tsk);
-       if (err)
-               goto out_ipc;
+       new_ns = create_new_namespaces(flags, tsk, tsk->fs);
+       if (IS_ERR(new_ns)) {
+               err = PTR_ERR(new_ns);
+               goto out;
+       }
 
+       tsk->nsproxy = new_ns;
 out:
        put_nsproxy(old_ns);
        return err;
-
-out_ipc:
-       if (new_ns->uts_ns)
-               put_uts_ns(new_ns->uts_ns);
-out_uts:
-       if (new_ns->namespace)
-               put_namespace(new_ns->namespace);
-out_ns:
-       tsk->nsproxy = old_ns;
-       kfree(new_ns);
-       goto out;
 }
 
 void free_nsproxy(struct nsproxy *ns)
 {
-               if (ns->namespace)
-                       put_namespace(ns->namespace);
-               if (ns->uts_ns)
-                       put_uts_ns(ns->uts_ns);
-               if (ns->ipc_ns)
-                       put_ipc_ns(ns->ipc_ns);
-               kfree(ns);
+       if (ns->mnt_ns)
+               put_mnt_ns(ns->mnt_ns);
+       if (ns->uts_ns)
+               put_uts_ns(ns->uts_ns);
+       if (ns->ipc_ns)
+               put_ipc_ns(ns->ipc_ns);
+       if (ns->pid_ns)
+               put_pid_ns(ns->pid_ns);
+       kfree(ns);
+}
+
+/*
+ * Called from unshare. Unshare all the namespaces part of nsproxy.
+ * On sucess, returns the new nsproxy and a reference to old nsproxy
+ * to make sure it stays around.
+ */
+int unshare_nsproxy_namespaces(unsigned long unshare_flags,
+               struct nsproxy **new_nsp, struct fs_struct *new_fs)
+{
+       struct nsproxy *old_ns = current->nsproxy;
+       int err = 0;
+
+       if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
+               return 0;
+
+#ifndef CONFIG_IPC_NS
+       if (unshare_flags & CLONE_NEWIPC)
+               return -EINVAL;
+#endif
+
+#ifndef CONFIG_UTS_NS
+       if (unshare_flags & CLONE_NEWUTS)
+               return -EINVAL;
+#endif
+
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
+
+       get_nsproxy(old_ns);
+
+       *new_nsp = create_new_namespaces(unshare_flags, current,
+                               new_fs ? new_fs : current->fs);
+       if (IS_ERR(*new_nsp)) {
+               err = PTR_ERR(*new_nsp);
+               put_nsproxy(old_ns);
+       }
+       return err;
 }