mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
Pull namespace changes from Eric Biederman: "This is an assorted mishmash of small cleanups, enhancements and bug fixes. The major theme is user namespace mount restrictions. nsown_capable is killed as it encourages not thinking about details that need to be considered. A very hard to hit pid namespace exiting bug was finally tracked and fixed. A couple of cleanups to the basic namespace infrastructure. Finally there is an enhancement that makes per user namespace capabilities usable as capabilities, and an enhancement that allows the per userns root to nice other processes in the user namespace" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: userns: Kill nsown_capable it makes the wrong thing easy capabilities: allow nice if we are privileged pidns: Don't have unshare(CLONE_NEWPID) imply CLONE_THREAD userns: Allow PR_CAPBSET_DROP in a user namespace. namespaces: Simplify copy_namespaces so it is clear what is going on. pidns: Fix hang in zap_pid_ns_processes by sending a potentially extra wakeup sysfs: Restrict mounting sysfs userns: Better restrictions on when proc and sysfs can be mounted vfs: Don't copy mount bind mounts of /proc/<pid>/ns/mnt between namespaces kernel/nsproxy.c: Improving a snippet of code. proc: Restrict mounting the proc filesystem vfs: Lock in place mounts from more privileged users
268 lines
6.3 KiB
C
268 lines
6.3 KiB
C
/*
|
|
* 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();
|
|
|
|
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_ns *ei;
|
|
struct file *file;
|
|
int err;
|
|
|
|
file = proc_ns_fget(fd);
|
|
if (IS_ERR(file))
|
|
return PTR_ERR(file);
|
|
|
|
err = -EINVAL;
|
|
ei = get_proc_ns(file_inode(file));
|
|
ops = ei->ns_ops;
|
|
if (nstype && (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 = 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;
|
|
}
|
|
|
|
int __init nsproxy_cache_init(void)
|
|
{
|
|
nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
|
|
return 0;
|
|
}
|