123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281 |
- /*
- * 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/module.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_fs.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 = &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 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, 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, tsk);
- if (IS_ERR(new_nsp->uts_ns)) {
- err = PTR_ERR(new_nsp->uts_ns);
- goto out_uts;
- }
- new_nsp->ipc_ns = copy_ipcs(flags, tsk);
- if (IS_ERR(new_nsp->ipc_ns)) {
- err = PTR_ERR(new_nsp->ipc_ns);
- goto out_ipc;
- }
- 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->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;
- }
- return new_nsp;
- out_net:
- if (new_nsp->pid_ns)
- put_pid_ns(new_nsp->pid_ns);
- 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 nsproxy *new_ns;
- int err = 0;
- if (!old_ns)
- return 0;
- get_nsproxy(old_ns);
- if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWPID | CLONE_NEWNET)))
- return 0;
- if (!capable(CAP_SYS_ADMIN)) {
- err = -EPERM;
- goto out;
- }
- /*
- * 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;
- }
- 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;
- }
- 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)
- put_pid_ns(ns->pid_ns);
- 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 fs_struct *new_fs)
- {
- int err = 0;
- if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWNET)))
- return 0;
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- *new_nsp = create_new_namespaces(unshare_flags, current,
- 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();
- 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);
- }
- SYSCALL_DEFINE2(setns, int, fd, int, nstype)
- {
- const struct proc_ns_operations *ops;
- struct task_struct *tsk = current;
- struct nsproxy *new_nsproxy;
- struct proc_inode *ei;
- struct file *file;
- int err;
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- file = proc_ns_fget(fd);
- if (IS_ERR(file))
- return PTR_ERR(file);
- err = -EINVAL;
- ei = PROC_I(file->f_dentry->d_inode);
- ops = ei->ns_ops;
- if (nstype && (ops->type != nstype))
- goto out;
- new_nsproxy = create_new_namespaces(0, tsk, tsk->fs);
- if (IS_ERR(new_nsproxy)) {
- err = PTR_ERR(new_nsproxy);
- goto out;
- }
- err = ops->install(new_nsproxy, ei->ns);
- if (err) {
- free_nsproxy(new_nsproxy);
- goto out;
- }
- switch_task_namespaces(tsk, new_nsproxy);
- out:
- fput(file);
- return err;
- }
- static int __init nsproxy_cache_init(void)
- {
- nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
- return 0;
- }
- module_init(nsproxy_cache_init);
|