aboutsummaryrefslogblamecommitdiffstats
path: root/kernel/nsproxy.c
blob: 2ab67233ee8f71bf43fd7f746438c652c891419f (plain) (tree)
1
2
3
4
5
6
7
8
9







                                                                  


                                                 

                         
                          
                            
                                
                          
                                
                              
                                
 
                                         










                                                           
 
                                                  
 
                                
 


                                                               

  

                                                                     
   
                                                                          
 
                                
                
 
                                   
                                        
 
                                                                           
                                               
                            
         
                                                                    
                                               
                             
         
                                                                 
                                               
                             
         
 
                                                                      
                                               
                             
         
 




                                                                   
                       
        
                                            








                                            
                                                 
                            




                                                                
                                                                 
                                              
                               




                            
                                                                  
                                                              
                         
                                      

                         










                                                                       



                                                            
 
                              
 
    
                            
                   


                                     






                                       
                            
                                            
 

                                                                   
                                       


                                                                   
                    
                                                                          
                                              
                         

                                    
                                                                
                               
                                        

                         
                                                          


                                      
                   
 

























                                                                           
                                          
                                                         


                                
/*
 *  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 = {
	.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->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->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;
	}

	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);