diff options
Diffstat (limited to 'kernel/nsproxy.c')
| -rw-r--r-- | kernel/nsproxy.c | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c new file mode 100644 index 0000000..1d3ef29 --- /dev/null +++ b/kernel/nsproxy.c @@ -0,0 +1,246 @@ +/* + * 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/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> + +static struct kmem_cache *nsproxy_cachep; + +struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy); + +/* + * creates a copy of "orig" with refcount 1. + */ +static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig) +{ + struct nsproxy *ns; + + ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL); + if (ns) { + memcpy(ns, orig, sizeof(struct nsproxy)); + atomic_set(&ns->count, 1); + } + return ns; +} + +/* + * 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 = clone_nsproxy(tsk->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->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, 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 = 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->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns); + if (IS_ERR(new_nsp->user_ns)) { + err = PTR_ERR(new_nsp->user_ns); + goto out_user; + } + + 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->user_ns) + put_user_ns(new_nsp->user_ns); +out_user: + 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_NEWUSER | 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); + if (ns->user_ns) + put_user_ns(ns->user_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_NEWUSER | 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; + } + + err = ns_cgroup_clone(current, task_pid(current)); + if (err) + put_nsproxy(*new_nsp); + +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); +} + +static int __init nsproxy_cache_init(void) +{ + nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); + return 0; +} + +module_init(nsproxy_cache_init); |
