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kernel/nsproxy.c
5.26 KB
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/* * 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. |
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* * Jun 2006 - namespaces support * OpenVZ, SWsoft Inc. * Pavel Emelianov <xemul@openvz.org> |
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*/ |
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#include <linux/slab.h> |
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#include <linux/module.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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static struct kmem_cache *nsproxy_cachep; |
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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 }; |
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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); if (nsproxy) atomic_set(&nsproxy->count, 1); return nsproxy; |
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} /* |
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* 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. |
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*/ |
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static struct nsproxy *create_new_namespaces(unsigned long flags, struct task_struct *tsk, 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) return ERR_PTR(-ENOMEM); |
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new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs); |
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if (IS_ERR(new_nsp->mnt_ns)) { 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, tsk->nsproxy->uts_ns); |
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if (IS_ERR(new_nsp->uts_ns)) { 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, tsk->nsproxy->ipc_ns); |
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if (IS_ERR(new_nsp->ipc_ns)) { 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 = copy_pid_ns(flags, task_active_pid_ns(tsk)); |
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if (IS_ERR(new_nsp->pid_ns)) { err = PTR_ERR(new_nsp->pid_ns); |
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goto out_pid; |
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} |
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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); goto out_net; } |
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return new_nsp; |
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out_net: |
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if (new_nsp->pid_ns) put_pid_ns(new_nsp->pid_ns); |
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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: |
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kmem_cache_free(nsproxy_cachep, new_nsp); |
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return ERR_PTR(err); |
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} /* * called from clone. This now handles copy for nsproxy and all * namespaces therein. */ |
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int copy_namespaces(unsigned long flags, struct task_struct *tsk) |
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{ struct nsproxy *old_ns = tsk->nsproxy; |
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struct nsproxy *new_ns; int err = 0; |
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if (!old_ns) return 0; get_nsproxy(old_ns); |
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if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | |
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CLONE_NEWPID | CLONE_NEWNET))) |
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return 0; |
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if (!capable(CAP_SYS_ADMIN)) { err = -EPERM; |
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goto out; } |
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/* * 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; } |
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new_ns = create_new_namespaces(flags, tsk, tsk->fs); if (IS_ERR(new_ns)) { err = PTR_ERR(new_ns); goto out; } |
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tsk->nsproxy = new_ns; |
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out: |
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put_nsproxy(old_ns); |
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return err; |
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} void free_nsproxy(struct nsproxy *ns) { |
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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); |
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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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/* * Called from unshare. Unshare all the namespaces part of nsproxy. |
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* On success, returns the new nsproxy. |
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*/ int unshare_nsproxy_namespaces(unsigned long unshare_flags, struct nsproxy **new_nsp, struct fs_struct *new_fs) { |
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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))) |
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return 0; |
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if (!capable(CAP_SYS_ADMIN)) return -EPERM; |
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*new_nsp = create_new_namespaces(unshare_flags, current, 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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err = ns_cgroup_clone(current, task_pid(current)); |
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if (err) put_nsproxy(*new_nsp); out: |
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return err; } |
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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); } |
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static int __init nsproxy_cache_init(void) { |
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nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); |
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return 0; } module_init(nsproxy_cache_init); |