175 lines
3.8 KiB
C
175 lines
3.8 KiB
C
/* Kernel module to match various things tied to sockets associated with
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locally generated outgoing packets. */
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/* (C) 2000-2001 Marc Boucher <marc@mbsi.ca>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/file.h>
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#include <net/sock.h>
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#include <linux/netfilter_ipv6/ip6t_owner.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
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MODULE_DESCRIPTION("IP6 tables owner matching module");
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MODULE_LICENSE("GPL");
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static int
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match_pid(const struct sk_buff *skb, pid_t pid)
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{
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struct task_struct *p;
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struct files_struct *files;
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int i;
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read_lock(&tasklist_lock);
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p = find_task_by_pid(pid);
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if (!p)
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goto out;
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task_lock(p);
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files = p->files;
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if(files) {
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spin_lock(&files->file_lock);
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for (i=0; i < files->max_fds; i++) {
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if (fcheck_files(files, i) == skb->sk->sk_socket->file) {
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spin_unlock(&files->file_lock);
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task_unlock(p);
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read_unlock(&tasklist_lock);
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return 1;
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}
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}
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spin_unlock(&files->file_lock);
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}
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task_unlock(p);
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out:
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read_unlock(&tasklist_lock);
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return 0;
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}
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static int
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match_sid(const struct sk_buff *skb, pid_t sid)
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{
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struct task_struct *g, *p;
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struct file *file = skb->sk->sk_socket->file;
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int i, found=0;
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read_lock(&tasklist_lock);
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do_each_thread(g, p) {
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struct files_struct *files;
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if (p->signal->session != sid)
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continue;
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task_lock(p);
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files = p->files;
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if (files) {
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spin_lock(&files->file_lock);
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for (i=0; i < files->max_fds; i++) {
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if (fcheck_files(files, i) == file) {
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found = 1;
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break;
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}
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}
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spin_unlock(&files->file_lock);
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}
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task_unlock(p);
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if (found)
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goto out;
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} while_each_thread(g, p);
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out:
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read_unlock(&tasklist_lock);
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return found;
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}
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static int
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match(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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const void *matchinfo,
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int offset,
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unsigned int protoff,
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int *hotdrop)
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{
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const struct ip6t_owner_info *info = matchinfo;
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if (!skb->sk || !skb->sk->sk_socket || !skb->sk->sk_socket->file)
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return 0;
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if(info->match & IP6T_OWNER_UID) {
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if((skb->sk->sk_socket->file->f_uid != info->uid) ^
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!!(info->invert & IP6T_OWNER_UID))
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return 0;
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}
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if(info->match & IP6T_OWNER_GID) {
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if((skb->sk->sk_socket->file->f_gid != info->gid) ^
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!!(info->invert & IP6T_OWNER_GID))
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return 0;
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}
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if(info->match & IP6T_OWNER_PID) {
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if (!match_pid(skb, info->pid) ^
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!!(info->invert & IP6T_OWNER_PID))
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return 0;
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}
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if(info->match & IP6T_OWNER_SID) {
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if (!match_sid(skb, info->sid) ^
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!!(info->invert & IP6T_OWNER_SID))
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return 0;
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}
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return 1;
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}
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static int
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checkentry(const char *tablename,
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const struct ip6t_ip6 *ip,
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void *matchinfo,
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unsigned int matchsize,
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unsigned int hook_mask)
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{
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if (hook_mask
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& ~((1 << NF_IP6_LOCAL_OUT) | (1 << NF_IP6_POST_ROUTING))) {
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printk("ip6t_owner: only valid for LOCAL_OUT or POST_ROUTING.\n");
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return 0;
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}
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if (matchsize != IP6T_ALIGN(sizeof(struct ip6t_owner_info)))
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return 0;
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#ifdef CONFIG_SMP
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/* files->file_lock can not be used in a BH */
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if (((struct ip6t_owner_info *)matchinfo)->match
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& (IP6T_OWNER_PID|IP6T_OWNER_SID)) {
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printk("ip6t_owner: pid and sid matching is broken on SMP.\n");
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return 0;
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}
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#endif
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return 1;
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}
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static struct ip6t_match owner_match = {
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.name = "owner",
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.match = &match,
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.checkentry = &checkentry,
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.me = THIS_MODULE,
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};
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static int __init init(void)
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{
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return ip6t_register_match(&owner_match);
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}
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static void __exit fini(void)
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{
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ip6t_unregister_match(&owner_match);
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}
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module_init(init);
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module_exit(fini);
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