linux/fs/proc/proc_net.c
Denis V. Lunev e5d69b9f4a [ATM]: Oops reading net/atm/arp
cat /proc/net/atm/arp causes the NULL pointer dereference in the
get_proc_net+0xc/0x3a. This happens as proc_get_net believes that the
parent proc dir entry contains struct net.

Fix this assumption for "net/atm" case.

The problem is introduced by the commit c0097b07abf5f92ab135d024dd41bd2aada1512f
from Eric W. Biederman/Daniel Lezcano.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 15:01:36 -08:00

165 lines
3.3 KiB
C

/*
* linux/fs/proc/net.c
*
* Copyright (C) 2007
*
* Author: Eric Biederman <ebiederm@xmission.com>
*
* proc net directory handling functions
*/
#include <asm/uaccess.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/smp_lock.h>
#include <linux/mount.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include <linux/seq_file.h>
#include "internal.h"
int seq_open_net(struct inode *ino, struct file *f,
const struct seq_operations *ops, int size)
{
struct net *net;
struct seq_net_private *p;
BUG_ON(size < sizeof(*p));
net = get_proc_net(ino);
if (net == NULL)
return -ENXIO;
p = __seq_open_private(f, ops, size);
if (p == NULL) {
put_net(net);
return -ENOMEM;
}
p->net = net;
return 0;
}
EXPORT_SYMBOL_GPL(seq_open_net);
int seq_release_net(struct inode *ino, struct file *f)
{
struct seq_file *seq;
struct seq_net_private *p;
seq = f->private_data;
p = seq->private;
put_net(p->net);
seq_release_private(ino, f);
return 0;
}
EXPORT_SYMBOL_GPL(seq_release_net);
struct proc_dir_entry *proc_net_fops_create(struct net *net,
const char *name, mode_t mode, const struct file_operations *fops)
{
struct proc_dir_entry *res;
res = create_proc_entry(name, mode, net->proc_net);
if (res)
res->proc_fops = fops;
return res;
}
EXPORT_SYMBOL_GPL(proc_net_fops_create);
void proc_net_remove(struct net *net, const char *name)
{
remove_proc_entry(name, net->proc_net);
}
EXPORT_SYMBOL_GPL(proc_net_remove);
struct net *get_proc_net(const struct inode *inode)
{
return maybe_get_net(PDE_NET(PDE(inode)));
}
EXPORT_SYMBOL_GPL(get_proc_net);
static struct proc_dir_entry *shadow_pde;
static struct proc_dir_entry *proc_net_shadow(struct task_struct *task,
struct proc_dir_entry *de)
{
return task->nsproxy->net_ns->proc_net;
}
struct proc_dir_entry *proc_net_mkdir(struct net *net, const char *name,
struct proc_dir_entry *parent)
{
struct proc_dir_entry *pde;
pde = proc_mkdir_mode(name, S_IRUGO | S_IXUGO, parent);
if (pde != NULL)
pde->data = net;
return pde;
}
EXPORT_SYMBOL_GPL(proc_net_mkdir);
static __net_init int proc_net_ns_init(struct net *net)
{
struct proc_dir_entry *root, *netd, *net_statd;
int err;
err = -ENOMEM;
root = kzalloc(sizeof(*root), GFP_KERNEL);
if (!root)
goto out;
err = -EEXIST;
netd = proc_net_mkdir(net, "net", root);
if (!netd)
goto free_root;
err = -EEXIST;
net_statd = proc_net_mkdir(net, "stat", netd);
if (!net_statd)
goto free_net;
root->data = net;
net->proc_net_root = root;
net->proc_net = netd;
net->proc_net_stat = net_statd;
err = 0;
out:
return err;
free_net:
remove_proc_entry("net", root);
free_root:
kfree(root);
goto out;
}
static __net_exit void proc_net_ns_exit(struct net *net)
{
remove_proc_entry("stat", net->proc_net);
remove_proc_entry("net", net->proc_net_root);
kfree(net->proc_net_root);
}
static struct pernet_operations __net_initdata proc_net_ns_ops = {
.init = proc_net_ns_init,
.exit = proc_net_ns_exit,
};
int __init proc_net_init(void)
{
shadow_pde = proc_mkdir("net", NULL);
shadow_pde->shadow_proc = proc_net_shadow;
return register_pernet_subsys(&proc_net_ns_ops);
}