// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2006 IBM Corporation
*
* Author: Serge Hallyn <[email protected]>
*
* Jun 2006 - namespaces support
* OpenVZ, SWsoft Inc.
* Pavel Emelianov <[email protected]>
*/
#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/time_namespace.h>
#include <linux/fs_struct.h>
#include <linux/proc_fs.h>
#include <linux/proc_ns.h>
#include <linux/file.h>
#include <linux/syscalls.h>
#include <linux/cgroup.h>
#include <linux/perf_event.h>
static struct kmem_cache *nsproxy_cachep;
struct nsproxy init_nsproxy = {
.count = REFCOUNT_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
#ifdef CONFIG_CGROUPS
.cgroup_ns = &init_cgroup_ns,
#endif
#ifdef CONFIG_TIME_NS
.time_ns = &init_time_ns,
.time_ns_for_children = &init_time_ns,
#endif
};
static inline struct nsproxy *create_nsproxy(void)
{
struct nsproxy *nsproxy;
nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
if (nsproxy)
refcount_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->cgroup_ns = copy_cgroup_ns(flags, user_ns,
tsk->nsproxy->cgroup_ns);
if (IS_ERR(new_nsp->cgroup_ns)) {
err = PTR_ERR(new_nsp->cgroup_ns);
goto out_cgroup;
}
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;
}
new_nsp->time_ns_for_children = copy_time_ns(flags, user_ns,
tsk->nsproxy->time_ns_for_children);
if (IS_ERR(new_nsp->time_ns_for_children)) {
err = PTR_ERR(new_nsp->time_ns_for_children);
goto out_time;
}
new_nsp->time_ns = get_time_ns(tsk->nsproxy->time_ns);
return new_nsp;
out_time:
put_net(new_nsp->net_ns);
out_net:
put_cgroup_ns(new_nsp->cgroup_ns);
out_cgroup:
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 |
CLONE_NEWCGROUP | CLONE_NEWTIME)))) {
if ((flags & CLONE_VM) ||
likely(old_ns->time_ns_for_children == old_ns->time_ns)) {
get_nsproxy(old_ns);
return 0;
}
} else 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);
if ((flags & CLONE_VM) == 0)
timens_on_fork(new_ns, tsk);
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);
if (ns->time_ns)
put_time_ns(ns->time_ns);
if (ns->time_ns_for_children)
put_time_ns(ns->time_ns_for_children);
put_cgroup_ns(ns->cgroup_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 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 | CLONE_NEWCGROUP |
CLONE_NEWTIME)))
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();
task_lock(p);
ns = p->nsproxy;
p->nsproxy = new;
task_unlock(p);
if (ns)
put_nsproxy(ns);
}
void exit_task_namespaces(struct task_struct *p)
{
switch_task_namespaces(p, NULL);
}
int exec_task_namespaces(void)
{
struct task_struct *tsk = current;
struct nsproxy *new;
if (tsk->nsproxy->time_ns_for_children == tsk->nsproxy->time_ns)
return 0;
new = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
if (IS_ERR(new))
return PTR_ERR(new);
timens_on_fork(new, tsk);
switch_task_namespaces(tsk, new);
return 0;
}
static int check_setns_flags(unsigned long flags)
{
if (!flags || (flags & ~(CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
CLONE_NEWNET | CLONE_NEWTIME | CLONE_NEWUSER |
CLONE_NEWPID | CLONE_NEWCGROUP)))
return -EINVAL;
#ifndef CONFIG_USER_NS
if (flags & CLONE_NEWUSER)
return -EINVAL;
#endif
#ifndef CONFIG_PID_NS
if (flags & CLONE_NEWPID)
return -EINVAL;
#endif
#ifndef CONFIG_UTS_NS
if (flags & CLONE_NEWUTS)
return -EINVAL;
#endif
#ifndef CONFIG_IPC_NS
if (flags & CLONE_NEWIPC)
return -EINVAL;
#endif
#ifndef CONFIG_CGROUPS
if (flags & CLONE_NEWCGROUP)
return -EINVAL;
#endif
#ifndef CONFIG_NET_NS
if (flags & CLONE_NEWNET)
return -EINVAL;
#endif
#ifndef CONFIG_TIME_NS
if (flags & CLONE_NEWTIME)
return -EINVAL;
#endif
return 0;
}
static void put_nsset(struct nsset *nsset)
{
unsigned flags = nsset->flags;
if (flags & CLONE_NEWUSER)
put_cred(nsset_cred(nsset));
/*
* We only created a temporary copy if we attached to more than just
* the mount namespace.
*/
if (nsset->fs && (flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS))
free_fs_struct(nsset->fs);
if (nsset->nsproxy)
free_nsproxy(nsset->nsproxy);
}
static int prepare_nsset(unsigned flags, struct nsset *nsset)
{
struct task_struct *me = current;
nsset->nsproxy = create_new_namespaces(0, me, current_user_ns(), me->fs);
if (IS_ERR(nsset->nsproxy))
return PTR_ERR(nsset->nsproxy);
if (flags & CLONE_NEWUSER)
nsset->cred = prepare_creds();
else
nsset->cred = current_cred();
if (!nsset->cred)
goto out;
/* Only create a temporary copy of fs_struct if we really need to. */
if (flags == CLONE_NEWNS) {
nsset->fs = me->fs;
} else if (flags & CLONE_NEWNS) {
nsset->fs = copy_fs_struct(me->fs);
if (!nsset->fs)
goto out;
}
nsset->flags = flags;
return 0;
out:
put_nsset(nsset);
return -ENOMEM;
}
static inline int validate_ns(struct nsset *nsset, struct ns_common *ns)
{
return ns->ops->install(nsset, ns);
}
/*
* This is the inverse operation to unshare().
* Ordering is equivalent to the standard ordering used everywhere else
* during unshare and process creation. The switch to the new set of
* namespaces occurs at the point of no return after installation of
* all requested namespaces was successful in commit_nsset().
*/
static int validate_nsset(struct nsset *nsset, struct pid *pid)
{
int ret = 0;
unsigned flags = nsset->flags;
struct user_namespace *user_ns = NULL;
struct pid_namespace *pid_ns = NULL;
struct nsproxy *nsp;
struct task_struct *tsk;
/* Take a "snapshot" of the target task's namespaces. */
rcu_read_lock();
tsk = pid_task(pid, PIDTYPE_PID);
if (!tsk) {
rcu_read_unlock();
return -ESRCH;
}
if (!ptrace_may_access(tsk, PTRACE_MODE_READ_REALCREDS)) {
rcu_read_unlock();
return -EPERM;
}
task_lock(tsk);
nsp = tsk->nsproxy;
if (nsp)
get_nsproxy(nsp);
task_unlock(tsk);
if (!nsp) {
rcu_read_unlock();
return -ESRCH;
}
#ifdef CONFIG_PID_NS
if (flags & CLONE_NEWPID) {
pid_ns = task_active_pid_ns(tsk);
if (unlikely(!pid_ns)) {
rcu_read_unlock();
ret = -ESRCH;
goto out;
}
get_pid_ns(pid_ns);
}
#endif
#ifdef CONFIG_USER_NS
if (flags & CLONE_NEWUSER)
user_ns = get_user_ns(__task_cred(tsk)->user_ns);
#endif
rcu_read_unlock();
/*
* Install requested namespaces. The caller will have
* verified earlier that the requested namespaces are
* supported on this kernel. We don't report errors here
* if a namespace is requested that isn't supported.
*/
#ifdef CONFIG_USER_NS
if (flags & CLONE_NEWUSER) {
ret = validate_ns(nsset, &user_ns->ns);
if (ret)
goto out;
}
#endif
if (flags & CLONE_NEWNS) {
ret = validate_ns(nsset, from_mnt_ns(nsp->mnt_ns));
if (ret)
goto out;
}
#ifdef CONFIG_UTS_NS
if (flags & CLONE_NEWUTS) {
ret = validate_ns(nsset, &nsp->uts_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_IPC_NS
if (flags & CLONE_NEWIPC) {
ret = validate_ns(nsset, &nsp->ipc_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_PID_NS
if (flags & CLONE_NEWPID) {
ret = validate_ns(nsset, &pid_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_CGROUPS
if (flags & CLONE_NEWCGROUP) {
ret = validate_ns(nsset, &nsp->cgroup_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_NET_NS
if (flags & CLONE_NEWNET) {
ret = validate_ns(nsset, &nsp->net_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_TIME_NS
if (flags & CLONE_NEWTIME) {
ret = validate_ns(nsset, &nsp->time_ns->ns);
if (ret)
goto out;
}
#endif
out:
if (pid_ns)
put_pid_ns(pid_ns);
if (nsp)
put_nsproxy(nsp);
put_user_ns(user_ns);
return ret;
}
/*
* This is the point of no return. There are just a few namespaces
* that do some actual work here and it's sufficiently minimal that
* a separate ns_common operation seems unnecessary for now.
* Unshare is doing the same thing. If we'll end up needing to do
* more in a given namespace or a helper here is ultimately not
* exported anymore a simple commit handler for each namespace
* should be added to ns_common.
*/
static void commit_nsset(struct nsset *nsset)
{
unsigned flags = nsset->flags;
struct task_struct *me = current;
#ifdef CONFIG_USER_NS
if (flags & CLONE_NEWUSER) {
/* transfer ownership */
commit_creds(nsset_cred(nsset));
nsset->cred = NULL;
}
#endif
/* We only need to commit if we have used a temporary fs_struct. */
if ((flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS)) {
set_fs_root(me->fs, &nsset->fs->root);
set_fs_pwd(me->fs, &nsset->fs->pwd);
}
#ifdef CONFIG_IPC_NS
if (flags & CLONE_NEWIPC)
exit_sem(me);
#endif
#ifdef CONFIG_TIME_NS
if (flags & CLONE_NEWTIME)
timens_commit(me, nsset->nsproxy->time_ns);
#endif
/* transfer ownership */
switch_task_namespaces(me, nsset->nsproxy);
nsset->nsproxy = NULL;
}
SYSCALL_DEFINE2(setns, int, fd, int, flags)
{
struct fd f = fdget(fd);
struct ns_common *ns = NULL;
struct nsset nsset = {};
int err = 0;
if (!fd_file(f))
return -EBADF;
if (proc_ns_file(fd_file(f))) {
ns = get_proc_ns(file_inode(fd_file(f)));
if (flags && (ns->ops->type != flags))
err = -EINVAL;
flags = ns->ops->type;
} else if (!IS_ERR(pidfd_pid(fd_file(f)))) {
err = check_setns_flags(flags);
} else {
err = -EINVAL;
}
if (err)
goto out;
err = prepare_nsset(flags, &nsset);
if (err)
goto out;
if (proc_ns_file(fd_file(f)))
err = validate_ns(&nsset, ns);
else
err = validate_nsset(&nsset, pidfd_pid(fd_file(f)));
if (!err) {
commit_nsset(&nsset);
perf_event_namespaces(current);
}
put_nsset(&nsset);
out:
fdput(f);
return err;
}
int __init nsproxy_cache_init(void)
{
nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC|SLAB_ACCOUNT);
return 0;
}
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