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/* Kernel module to match various things tied to sockets associated with
locally generated outgoing packets.
Copyright (C) 2000 Marc Boucher
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/file.h>
#include <net/sock.h>
#include <linux/netfilter_ipv4/ipt_owner.h>
#include <linux/netfilter_ipv4/ip_tables.h>
static int
match_pid(const struct sk_buff *skb, pid_t pid)
{
struct task_struct *p;
int i;
read_lock(&tasklist_lock);
p = find_task_by_pid(pid);
if(p && p->files) {
for (i=0; i < p->files->max_fds; i++) {
if (fcheck_files(p->files, i) == skb->sk->socket->file) {
read_unlock(&tasklist_lock);
return 1;
}
}
}
read_unlock(&tasklist_lock);
return 0;
}
static int
match_sid(const struct sk_buff *skb, pid_t sid)
{
struct task_struct *p;
int i, found=0;
read_lock(&tasklist_lock);
for_each_task(p) {
if ((p->session != sid) || !p->files)
continue;
for (i=0; i < p->files->max_fds; i++) {
if (fcheck_files(p->files, i) == skb->sk->socket->file) {
found = 1;
break;
}
}
if(found)
break;
}
read_unlock(&tasklist_lock);
return found;
}
static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_owner_info *info = matchinfo;
if (!skb->sk || !skb->sk->socket || !skb->sk->socket->file)
return 0;
if(info->match & IPT_OWNER_UID) {
if((skb->sk->socket->file->f_uid != info->uid) ^
!!(info->invert & IPT_OWNER_UID))
return 0;
}
if(info->match & IPT_OWNER_GID) {
if((skb->sk->socket->file->f_gid != info->gid) ^
!!(info->invert & IPT_OWNER_GID))
return 0;
}
if(info->match & IPT_OWNER_PID) {
if (!match_pid(skb, info->pid) ^
!!(info->invert & IPT_OWNER_PID))
return 0;
}
if(info->match & IPT_OWNER_SID) {
if (!match_sid(skb, info->sid) ^
!!(info->invert & IPT_OWNER_SID))
return 0;
}
return 1;
}
static int
checkentry(const char *tablename,
const struct ipt_ip *ip,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
if (hook_mask
& ~((1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_POST_ROUTING))) {
printk("ipt_owner: only valid for LOCAL_OUT or POST_ROUTING.\n");
return 0;
}
if (matchsize != IPT_ALIGN(sizeof(struct ipt_owner_info)))
return 0;
return 1;
}
static struct ipt_match owner_match
= { { NULL, NULL }, "owner", &match, &checkentry, NULL, THIS_MODULE };
static int __init init(void)
{
return ipt_register_match(&owner_match);
}
static void __exit fini(void)
{
ipt_unregister_match(&owner_match);
}
module_init(init);
module_exit(fini);
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