linux_dsm_epyc7002/fs/proc/proc_net.c
Eric W. Biederman 2b1e300a9d [NETNS]: Fix /proc/net breakage
Well I clearly goofed when I added the initial network namespace support
for /proc/net.  Currently things work but there are odd details visible to
user space, even when we have a single network namespace.

Since we do not cache proc_dir_entry dentries at the moment we can just
modify ->lookup to return a different directory inode depending on the
network namespace of the process looking at /proc/net, replacing the
current technique of using a magic and fragile follow_link method.

To accomplish that this patch:
- introduces a shadow_proc method to allow different dentries to
  be returned from proc_lookup.
- Removes the old /proc/net follow_link magic
- Fixes a weakness in our not caching of proc generic dentries.

As shadow_proc uses a task struct to decided which dentry to return we can
go back later and fix the proc generic caching without modifying any code
that uses the shadow_proc method.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-12-02 00:33:17 +11:00

118 lines
2.3 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 "internal.h"
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;
}
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_mkdir("net", root);
if (!netd)
goto free_root;
err = -EEXIST;
net_statd = proc_mkdir("stat", netd);
if (!net_statd)
goto free_net;
root->data = net;
netd->data = net;
net_statd->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);
}