linux/kernel/nsproxy.c
Pavel 5d124e99c2 [PATCH] nsproxy cloning error path fix
This patch fixes copy_namespaces()'s error path.

when new nsproxy (new_ns) is created pointers to namespaces (ipc, uts) are
copied from the old nsproxy.  Later in copy_utsname, copy_ipcs, etc.
according namespaces are get-ed.  On error path needed namespaces are
put-ed, so there's no need to put new nsproxy itelf as it woud cause
putting namespaces for the second time.

Found when incorporating namespaces into OpenVZ kernel.

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02 07:57:22 -07:00

139 lines
2.7 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/module.h>
#include <linux/version.h>
#include <linux/nsproxy.h>
#include <linux/init_task.h>
#include <linux/namespace.h>
#include <linux/utsname.h>
struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
static inline void get_nsproxy(struct nsproxy *ns)
{
atomic_inc(&ns->count);
}
void get_task_namespaces(struct task_struct *tsk)
{
struct nsproxy *ns = tsk->nsproxy;
if (ns) {
get_nsproxy(ns);
}
}
/*
* creates a copy of "orig" with refcount 1.
* This does not grab references to the contained namespaces,
* so that needs to be done by dup_namespaces.
*/
static inline struct nsproxy *clone_namespaces(struct nsproxy *orig)
{
struct nsproxy *ns;
ns = kmalloc(sizeof(struct nsproxy), GFP_KERNEL);
if (ns) {
memcpy(ns, orig, sizeof(struct nsproxy));
atomic_set(&ns->count, 1);
}
return ns;
}
/*
* copies the nsproxy, setting refcount to 1, and grabbing a
* reference to all contained namespaces. Called from
* sys_unshare()
*/
struct nsproxy *dup_namespaces(struct nsproxy *orig)
{
struct nsproxy *ns = clone_namespaces(orig);
if (ns) {
if (ns->namespace)
get_namespace(ns->namespace);
if (ns->uts_ns)
get_uts_ns(ns->uts_ns);
if (ns->ipc_ns)
get_ipc_ns(ns->ipc_ns);
}
return ns;
}
/*
* called from clone. This now handles copy for nsproxy and all
* namespaces therein.
*/
int copy_namespaces(int 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)))
return 0;
new_ns = clone_namespaces(old_ns);
if (!new_ns) {
err = -ENOMEM;
goto out;
}
tsk->nsproxy = new_ns;
err = copy_namespace(flags, tsk);
if (err)
goto out_ns;
err = copy_utsname(flags, tsk);
if (err)
goto out_uts;
err = copy_ipcs(flags, tsk);
if (err)
goto out_ipc;
out:
put_nsproxy(old_ns);
return err;
out_ipc:
if (new_ns->uts_ns)
put_uts_ns(new_ns->uts_ns);
out_uts:
if (new_ns->namespace)
put_namespace(new_ns->namespace);
out_ns:
tsk->nsproxy = old_ns;
kfree(new_ns);
goto out;
}
void free_nsproxy(struct nsproxy *ns)
{
if (ns->namespace)
put_namespace(ns->namespace);
if (ns->uts_ns)
put_uts_ns(ns->uts_ns);
if (ns->ipc_ns)
put_ipc_ns(ns->ipc_ns);
kfree(ns);
}