269 lines
6.3 KiB
C
269 lines
6.3 KiB
C
/*
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* Copyright (C) 2006 IBM Corporation
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*
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* Author: Serge Hallyn <serue@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*
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* Jun 2006 - namespaces support
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* OpenVZ, SWsoft Inc.
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* Pavel Emelianov <xemul@openvz.org>
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*/
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <linux/nsproxy.h>
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#include <linux/init_task.h>
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#include <linux/mnt_namespace.h>
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#include <linux/utsname.h>
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#include <linux/pid_namespace.h>
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#include <net/net_namespace.h>
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#include <linux/ipc_namespace.h>
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#include <linux/proc_ns.h>
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#include <linux/file.h>
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#include <linux/syscalls.h>
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static struct kmem_cache *nsproxy_cachep;
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struct nsproxy init_nsproxy = {
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.count = ATOMIC_INIT(1),
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.uts_ns = &init_uts_ns,
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#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
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.ipc_ns = &init_ipc_ns,
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#endif
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.mnt_ns = NULL,
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.pid_ns_for_children = &init_pid_ns,
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#ifdef CONFIG_NET
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.net_ns = &init_net,
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#endif
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};
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static inline struct nsproxy *create_nsproxy(void)
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{
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struct nsproxy *nsproxy;
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nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
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if (nsproxy)
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atomic_set(&nsproxy->count, 1);
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return nsproxy;
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}
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/*
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* Create new nsproxy and all of its the associated namespaces.
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* Return the newly created nsproxy. Do not attach this to the task,
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* leave it to the caller to do proper locking and attach it to task.
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*/
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static struct nsproxy *create_new_namespaces(unsigned long flags,
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struct task_struct *tsk, struct user_namespace *user_ns,
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struct fs_struct *new_fs)
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{
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struct nsproxy *new_nsp;
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int err;
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new_nsp = create_nsproxy();
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if (!new_nsp)
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return ERR_PTR(-ENOMEM);
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new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
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if (IS_ERR(new_nsp->mnt_ns)) {
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err = PTR_ERR(new_nsp->mnt_ns);
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goto out_ns;
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}
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new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
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if (IS_ERR(new_nsp->uts_ns)) {
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err = PTR_ERR(new_nsp->uts_ns);
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goto out_uts;
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}
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new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
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if (IS_ERR(new_nsp->ipc_ns)) {
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err = PTR_ERR(new_nsp->ipc_ns);
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goto out_ipc;
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}
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new_nsp->pid_ns_for_children =
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copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
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if (IS_ERR(new_nsp->pid_ns_for_children)) {
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err = PTR_ERR(new_nsp->pid_ns_for_children);
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goto out_pid;
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}
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new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
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if (IS_ERR(new_nsp->net_ns)) {
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err = PTR_ERR(new_nsp->net_ns);
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goto out_net;
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}
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return new_nsp;
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out_net:
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if (new_nsp->pid_ns_for_children)
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put_pid_ns(new_nsp->pid_ns_for_children);
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out_pid:
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if (new_nsp->ipc_ns)
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put_ipc_ns(new_nsp->ipc_ns);
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out_ipc:
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if (new_nsp->uts_ns)
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put_uts_ns(new_nsp->uts_ns);
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out_uts:
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if (new_nsp->mnt_ns)
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put_mnt_ns(new_nsp->mnt_ns);
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out_ns:
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kmem_cache_free(nsproxy_cachep, new_nsp);
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return ERR_PTR(err);
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}
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/*
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* called from clone. This now handles copy for nsproxy and all
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* namespaces therein.
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*/
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int copy_namespaces(unsigned long flags, struct task_struct *tsk)
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{
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struct nsproxy *old_ns = tsk->nsproxy;
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struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
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struct nsproxy *new_ns;
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if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
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CLONE_NEWPID | CLONE_NEWNET)))) {
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get_nsproxy(old_ns);
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return 0;
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}
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if (!ns_capable(user_ns, CAP_SYS_ADMIN))
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return -EPERM;
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/*
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* CLONE_NEWIPC must detach from the undolist: after switching
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* to a new ipc namespace, the semaphore arrays from the old
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* namespace are unreachable. In clone parlance, CLONE_SYSVSEM
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* means share undolist with parent, so we must forbid using
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* it along with CLONE_NEWIPC.
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*/
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if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
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(CLONE_NEWIPC | CLONE_SYSVSEM))
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return -EINVAL;
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new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
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if (IS_ERR(new_ns))
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return PTR_ERR(new_ns);
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tsk->nsproxy = new_ns;
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return 0;
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}
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void free_nsproxy(struct nsproxy *ns)
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{
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if (ns->mnt_ns)
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put_mnt_ns(ns->mnt_ns);
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if (ns->uts_ns)
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put_uts_ns(ns->uts_ns);
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if (ns->ipc_ns)
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put_ipc_ns(ns->ipc_ns);
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if (ns->pid_ns_for_children)
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put_pid_ns(ns->pid_ns_for_children);
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put_net(ns->net_ns);
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kmem_cache_free(nsproxy_cachep, ns);
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}
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/*
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* Called from unshare. Unshare all the namespaces part of nsproxy.
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* On success, returns the new nsproxy.
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*/
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int unshare_nsproxy_namespaces(unsigned long unshare_flags,
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struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
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{
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struct user_namespace *user_ns;
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int err = 0;
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if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
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CLONE_NEWNET | CLONE_NEWPID)))
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return 0;
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user_ns = new_cred ? new_cred->user_ns : current_user_ns();
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if (!ns_capable(user_ns, CAP_SYS_ADMIN))
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return -EPERM;
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*new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
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new_fs ? new_fs : current->fs);
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if (IS_ERR(*new_nsp)) {
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err = PTR_ERR(*new_nsp);
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goto out;
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}
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out:
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return err;
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}
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void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
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{
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struct nsproxy *ns;
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might_sleep();
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ns = p->nsproxy;
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rcu_assign_pointer(p->nsproxy, new);
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if (ns && atomic_dec_and_test(&ns->count)) {
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/*
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* wait for others to get what they want from this nsproxy.
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*
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* cannot release this nsproxy via the call_rcu() since
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* put_mnt_ns() will want to sleep
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*/
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synchronize_rcu();
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free_nsproxy(ns);
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}
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}
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void exit_task_namespaces(struct task_struct *p)
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{
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switch_task_namespaces(p, NULL);
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}
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SYSCALL_DEFINE2(setns, int, fd, int, nstype)
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{
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const struct proc_ns_operations *ops;
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struct task_struct *tsk = current;
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struct nsproxy *new_nsproxy;
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struct proc_ns *ei;
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struct file *file;
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int err;
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file = proc_ns_fget(fd);
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if (IS_ERR(file))
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return PTR_ERR(file);
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err = -EINVAL;
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ei = get_proc_ns(file_inode(file));
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ops = ei->ns_ops;
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if (nstype && (ops->type != nstype))
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goto out;
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new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
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if (IS_ERR(new_nsproxy)) {
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err = PTR_ERR(new_nsproxy);
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goto out;
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}
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err = ops->install(new_nsproxy, ei->ns);
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if (err) {
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free_nsproxy(new_nsproxy);
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goto out;
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}
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switch_task_namespaces(tsk, new_nsproxy);
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out:
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fput(file);
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return err;
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}
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int __init nsproxy_cache_init(void)
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{
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nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
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return 0;
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}
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