In case of an unknown verdict or NF_STOP the packet leaks. Unknown verdicts can happen when userspace is buggy. Reinject the packet in case of NF_STOP, drop on unknown verdicts. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
316 lines
6.9 KiB
C
316 lines
6.9 KiB
C
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/netfilter.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <net/protocol.h>
|
|
|
|
#include "nf_internals.h"
|
|
|
|
/*
|
|
* A queue handler may be registered for each protocol. Each is protected by
|
|
* long term mutex. The handler must provide an an outfn() to accept packets
|
|
* for queueing and must reinject all packets it receives, no matter what.
|
|
*/
|
|
static struct nf_queue_handler *queue_handler[NPROTO];
|
|
|
|
static DEFINE_RWLOCK(queue_handler_lock);
|
|
|
|
/* return EBUSY when somebody else is registered, return EEXIST if the
|
|
* same handler is registered, return 0 in case of success. */
|
|
int nf_register_queue_handler(int pf, struct nf_queue_handler *qh)
|
|
{
|
|
int ret;
|
|
|
|
if (pf >= NPROTO)
|
|
return -EINVAL;
|
|
|
|
write_lock_bh(&queue_handler_lock);
|
|
if (queue_handler[pf] == qh)
|
|
ret = -EEXIST;
|
|
else if (queue_handler[pf])
|
|
ret = -EBUSY;
|
|
else {
|
|
queue_handler[pf] = qh;
|
|
ret = 0;
|
|
}
|
|
write_unlock_bh(&queue_handler_lock);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(nf_register_queue_handler);
|
|
|
|
/* The caller must flush their queue before this */
|
|
int nf_unregister_queue_handler(int pf)
|
|
{
|
|
if (pf >= NPROTO)
|
|
return -EINVAL;
|
|
|
|
write_lock_bh(&queue_handler_lock);
|
|
queue_handler[pf] = NULL;
|
|
write_unlock_bh(&queue_handler_lock);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(nf_unregister_queue_handler);
|
|
|
|
void nf_unregister_queue_handlers(struct nf_queue_handler *qh)
|
|
{
|
|
int pf;
|
|
|
|
write_lock_bh(&queue_handler_lock);
|
|
for (pf = 0; pf < NPROTO; pf++) {
|
|
if (queue_handler[pf] == qh)
|
|
queue_handler[pf] = NULL;
|
|
}
|
|
write_unlock_bh(&queue_handler_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers);
|
|
|
|
/*
|
|
* Any packet that leaves via this function must come back
|
|
* through nf_reinject().
|
|
*/
|
|
int nf_queue(struct sk_buff **skb,
|
|
struct list_head *elem,
|
|
int pf, unsigned int hook,
|
|
struct net_device *indev,
|
|
struct net_device *outdev,
|
|
int (*okfn)(struct sk_buff *),
|
|
unsigned int queuenum)
|
|
{
|
|
int status;
|
|
struct nf_info *info;
|
|
#ifdef CONFIG_BRIDGE_NETFILTER
|
|
struct net_device *physindev = NULL;
|
|
struct net_device *physoutdev = NULL;
|
|
#endif
|
|
struct nf_afinfo *afinfo;
|
|
|
|
/* QUEUE == DROP if noone is waiting, to be safe. */
|
|
read_lock(&queue_handler_lock);
|
|
if (!queue_handler[pf]) {
|
|
read_unlock(&queue_handler_lock);
|
|
kfree_skb(*skb);
|
|
return 1;
|
|
}
|
|
|
|
afinfo = nf_get_afinfo(pf);
|
|
if (!afinfo) {
|
|
read_unlock(&queue_handler_lock);
|
|
kfree_skb(*skb);
|
|
return 1;
|
|
}
|
|
|
|
info = kmalloc(sizeof(*info) + afinfo->route_key_size, GFP_ATOMIC);
|
|
if (!info) {
|
|
if (net_ratelimit())
|
|
printk(KERN_ERR "OOM queueing packet %p\n",
|
|
*skb);
|
|
read_unlock(&queue_handler_lock);
|
|
kfree_skb(*skb);
|
|
return 1;
|
|
}
|
|
|
|
*info = (struct nf_info) {
|
|
(struct nf_hook_ops *)elem, pf, hook, indev, outdev, okfn };
|
|
|
|
/* If it's going away, ignore hook. */
|
|
if (!try_module_get(info->elem->owner)) {
|
|
read_unlock(&queue_handler_lock);
|
|
kfree(info);
|
|
return 0;
|
|
}
|
|
|
|
/* Bump dev refs so they don't vanish while packet is out */
|
|
if (indev) dev_hold(indev);
|
|
if (outdev) dev_hold(outdev);
|
|
|
|
#ifdef CONFIG_BRIDGE_NETFILTER
|
|
if ((*skb)->nf_bridge) {
|
|
physindev = (*skb)->nf_bridge->physindev;
|
|
if (physindev) dev_hold(physindev);
|
|
physoutdev = (*skb)->nf_bridge->physoutdev;
|
|
if (physoutdev) dev_hold(physoutdev);
|
|
}
|
|
#endif
|
|
afinfo->saveroute(*skb, info);
|
|
status = queue_handler[pf]->outfn(*skb, info, queuenum,
|
|
queue_handler[pf]->data);
|
|
|
|
read_unlock(&queue_handler_lock);
|
|
|
|
if (status < 0) {
|
|
/* James M doesn't say fuck enough. */
|
|
if (indev) dev_put(indev);
|
|
if (outdev) dev_put(outdev);
|
|
#ifdef CONFIG_BRIDGE_NETFILTER
|
|
if (physindev) dev_put(physindev);
|
|
if (physoutdev) dev_put(physoutdev);
|
|
#endif
|
|
module_put(info->elem->owner);
|
|
kfree(info);
|
|
kfree_skb(*skb);
|
|
|
|
return 1;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
void nf_reinject(struct sk_buff *skb, struct nf_info *info,
|
|
unsigned int verdict)
|
|
{
|
|
struct list_head *elem = &info->elem->list;
|
|
struct list_head *i;
|
|
struct nf_afinfo *afinfo;
|
|
|
|
rcu_read_lock();
|
|
|
|
/* Release those devices we held, or Alexey will kill me. */
|
|
if (info->indev) dev_put(info->indev);
|
|
if (info->outdev) dev_put(info->outdev);
|
|
#ifdef CONFIG_BRIDGE_NETFILTER
|
|
if (skb->nf_bridge) {
|
|
if (skb->nf_bridge->physindev)
|
|
dev_put(skb->nf_bridge->physindev);
|
|
if (skb->nf_bridge->physoutdev)
|
|
dev_put(skb->nf_bridge->physoutdev);
|
|
}
|
|
#endif
|
|
|
|
/* Drop reference to owner of hook which queued us. */
|
|
module_put(info->elem->owner);
|
|
|
|
list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) {
|
|
if (i == elem)
|
|
break;
|
|
}
|
|
|
|
if (i == &nf_hooks[info->pf][info->hook]) {
|
|
/* The module which sent it to userspace is gone. */
|
|
NFDEBUG("%s: module disappeared, dropping packet.\n",
|
|
__FUNCTION__);
|
|
verdict = NF_DROP;
|
|
}
|
|
|
|
/* Continue traversal iff userspace said ok... */
|
|
if (verdict == NF_REPEAT) {
|
|
elem = elem->prev;
|
|
verdict = NF_ACCEPT;
|
|
}
|
|
|
|
if (verdict == NF_ACCEPT) {
|
|
afinfo = nf_get_afinfo(info->pf);
|
|
if (!afinfo || afinfo->reroute(&skb, info) < 0)
|
|
verdict = NF_DROP;
|
|
}
|
|
|
|
if (verdict == NF_ACCEPT) {
|
|
next_hook:
|
|
verdict = nf_iterate(&nf_hooks[info->pf][info->hook],
|
|
&skb, info->hook,
|
|
info->indev, info->outdev, &elem,
|
|
info->okfn, INT_MIN);
|
|
}
|
|
|
|
switch (verdict & NF_VERDICT_MASK) {
|
|
case NF_ACCEPT:
|
|
case NF_STOP:
|
|
info->okfn(skb);
|
|
case NF_STOLEN:
|
|
break;
|
|
case NF_QUEUE:
|
|
if (!nf_queue(&skb, elem, info->pf, info->hook,
|
|
info->indev, info->outdev, info->okfn,
|
|
verdict >> NF_VERDICT_BITS))
|
|
goto next_hook;
|
|
break;
|
|
default:
|
|
kfree_skb(skb);
|
|
}
|
|
rcu_read_unlock();
|
|
kfree(info);
|
|
return;
|
|
}
|
|
EXPORT_SYMBOL(nf_reinject);
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
static void *seq_start(struct seq_file *seq, loff_t *pos)
|
|
{
|
|
if (*pos >= NPROTO)
|
|
return NULL;
|
|
|
|
return pos;
|
|
}
|
|
|
|
static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
|
|
{
|
|
(*pos)++;
|
|
|
|
if (*pos >= NPROTO)
|
|
return NULL;
|
|
|
|
return pos;
|
|
}
|
|
|
|
static void seq_stop(struct seq_file *s, void *v)
|
|
{
|
|
|
|
}
|
|
|
|
static int seq_show(struct seq_file *s, void *v)
|
|
{
|
|
int ret;
|
|
loff_t *pos = v;
|
|
struct nf_queue_handler *qh;
|
|
|
|
read_lock_bh(&queue_handler_lock);
|
|
qh = queue_handler[*pos];
|
|
if (!qh)
|
|
ret = seq_printf(s, "%2lld NONE\n", *pos);
|
|
else
|
|
ret = seq_printf(s, "%2lld %s\n", *pos, qh->name);
|
|
read_unlock_bh(&queue_handler_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct seq_operations nfqueue_seq_ops = {
|
|
.start = seq_start,
|
|
.next = seq_next,
|
|
.stop = seq_stop,
|
|
.show = seq_show,
|
|
};
|
|
|
|
static int nfqueue_open(struct inode *inode, struct file *file)
|
|
{
|
|
return seq_open(file, &nfqueue_seq_ops);
|
|
}
|
|
|
|
static struct file_operations nfqueue_file_ops = {
|
|
.owner = THIS_MODULE,
|
|
.open = nfqueue_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release,
|
|
};
|
|
#endif /* PROC_FS */
|
|
|
|
|
|
int __init netfilter_queue_init(void)
|
|
{
|
|
#ifdef CONFIG_PROC_FS
|
|
struct proc_dir_entry *pde;
|
|
|
|
pde = create_proc_entry("nf_queue", S_IRUGO, proc_net_netfilter);
|
|
if (!pde)
|
|
return -1;
|
|
pde->proc_fops = &nfqueue_file_ops;
|
|
#endif
|
|
return 0;
|
|
}
|
|
|