--- /dev/null
+/*
+ * Copyright (C) 2006 IBM Corporation
+ *
+ * Author: Serge Hallyn <serue@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * Jun 2006 - namespaces support
+ * OpenVZ, SWsoft Inc.
+ * Pavel Emelianov <xemul@openvz.org>
+ */
+
+#include <linux/slab.h>
+#include <linux/export.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>
+#include <linux/proc_ns.h>
+#include <linux/file.h>
+#include <linux/syscalls.h>
+
+static struct kmem_cache *nsproxy_cachep;
+
+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_for_children = &init_pid_ns,
+#ifdef CONFIG_NET
+ .net_ns = &init_net,
+#endif
+};
+
+static inline struct nsproxy *create_nsproxy(void)
+{
+ struct nsproxy *nsproxy;
+
+ nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
+ if (nsproxy)
+ atomic_set(&nsproxy->count, 1);
+ return nsproxy;
+}
+
+/*
+ * 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.
+ */
+static struct nsproxy *create_new_namespaces(unsigned long flags,
+ struct task_struct *tsk, struct user_namespace *user_ns,
+ struct fs_struct *new_fs)
+{
+ struct nsproxy *new_nsp;
+ int err;
+
+ new_nsp = create_nsproxy();
+ if (!new_nsp)
+ return ERR_PTR(-ENOMEM);
+
+ new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
+ if (IS_ERR(new_nsp->mnt_ns)) {
+ err = PTR_ERR(new_nsp->mnt_ns);
+ goto out_ns;
+ }
+
+ new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
+ if (IS_ERR(new_nsp->uts_ns)) {
+ err = PTR_ERR(new_nsp->uts_ns);
+ goto out_uts;
+ }
+
+ new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
+ if (IS_ERR(new_nsp->ipc_ns)) {
+ err = PTR_ERR(new_nsp->ipc_ns);
+ goto out_ipc;
+ }
+
+ new_nsp->pid_ns_for_children =
+ copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
+ if (IS_ERR(new_nsp->pid_ns_for_children)) {
+ err = PTR_ERR(new_nsp->pid_ns_for_children);
+ goto out_pid;
+ }
+
+ new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
+ if (IS_ERR(new_nsp->net_ns)) {
+ err = PTR_ERR(new_nsp->net_ns);
+ goto out_net;
+ }
+
+ return new_nsp;
+
+out_net:
+ if (new_nsp->pid_ns_for_children)
+ put_pid_ns(new_nsp->pid_ns_for_children);
+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:
+ kmem_cache_free(nsproxy_cachep, new_nsp);
+ return ERR_PTR(err);
+}
+
+/*
+ * called from clone. This now handles copy for nsproxy and all
+ * namespaces therein.
+ */
+int copy_namespaces(unsigned long flags, struct task_struct *tsk)
+{
+ struct nsproxy *old_ns = tsk->nsproxy;
+ struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
+ struct nsproxy *new_ns;
+
+ if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+ CLONE_NEWPID | CLONE_NEWNET)))) {
+ get_nsproxy(old_ns);
+ return 0;
+ }
+
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /*
+ * 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 | CLONE_SYSVSEM)) ==
+ (CLONE_NEWIPC | CLONE_SYSVSEM))
+ return -EINVAL;
+
+ new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
+ if (IS_ERR(new_ns))
+ return PTR_ERR(new_ns);
+
+ tsk->nsproxy = new_ns;
+ return 0;
+}
+
+void free_nsproxy(struct nsproxy *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_for_children)
+ put_pid_ns(ns->pid_ns_for_children);
+ put_net(ns->net_ns);
+ kmem_cache_free(nsproxy_cachep, ns);
+}
+
+/*
+ * Called from unshare. Unshare all the namespaces part of nsproxy.
+ * On success, returns the new nsproxy.
+ */
+int unshare_nsproxy_namespaces(unsigned long unshare_flags,
+ struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
+{
+ struct user_namespace *user_ns;
+ int err = 0;
+
+ if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+ CLONE_NEWNET | CLONE_NEWPID)))
+ return 0;
+
+ user_ns = new_cred ? new_cred->user_ns : current_user_ns();
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ *new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
+ new_fs ? new_fs : current->fs);
+ if (IS_ERR(*new_nsp)) {
+ err = PTR_ERR(*new_nsp);
+ goto out;
+ }
+
+out:
+ return err;
+}
+
+void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
+{
+ struct nsproxy *ns;
+
+ might_sleep();
+
+ task_lock(p);
+ ns = p->nsproxy;
+ p->nsproxy = new;
+ task_unlock(p);
+
+ if (ns && atomic_dec_and_test(&ns->count))
+ free_nsproxy(ns);
+}
+
+void exit_task_namespaces(struct task_struct *p)
+{
+ switch_task_namespaces(p, NULL);
+}
+
+SYSCALL_DEFINE2(setns, int, fd, int, nstype)
+{
+ struct task_struct *tsk = current;
+ struct nsproxy *new_nsproxy;
+ struct file *file;
+ struct ns_common *ns;
+ int err;
+
+ file = proc_ns_fget(fd);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+
+ err = -EINVAL;
+ ns = get_proc_ns(file_inode(file));
+ if (nstype && (ns->ops->type != nstype))
+ goto out;
+
+ new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
+ if (IS_ERR(new_nsproxy)) {
+ err = PTR_ERR(new_nsproxy);
+ goto out;
+ }
+
+ err = ns->ops->install(new_nsproxy, ns);
+ if (err) {
+ free_nsproxy(new_nsproxy);
+ goto out;
+ }
+ switch_task_namespaces(tsk, new_nsproxy);
+out:
+ fput(file);
+ return err;
+}
+
+int __init nsproxy_cache_init(void)
+{
+ nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff