f564650106
Netfilter assumes that if the socket is present in the skb, then it can be used because that reference is cleaned up while the skb is crossing netns. We want to change that to preserve the socket reference in a future patch, so this is a preparation updating netfilter to check if the socket netns matches before use it. Signed-off-by: Flavio Leitner <fbl@redhat.com> Acked-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
151 lines
3.8 KiB
C
151 lines
3.8 KiB
C
/*
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* Xtables module to match the process control group.
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*
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* Might be used to implement individual "per-application" firewall
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* policies in contrast to global policies based on control groups.
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* Matching is based upon processes tagged to net_cls' classid marker.
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*
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* (C) 2013 Daniel Borkmann <dborkman@redhat.com>
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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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/skbuff.h>
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#include <linux/module.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_cgroup.h>
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#include <net/sock.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
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MODULE_DESCRIPTION("Xtables: process control group matching");
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MODULE_ALIAS("ipt_cgroup");
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MODULE_ALIAS("ip6t_cgroup");
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static int cgroup_mt_check_v0(const struct xt_mtchk_param *par)
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{
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struct xt_cgroup_info_v0 *info = par->matchinfo;
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if (info->invert & ~1)
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return -EINVAL;
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return 0;
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}
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static int cgroup_mt_check_v1(const struct xt_mtchk_param *par)
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{
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struct xt_cgroup_info_v1 *info = par->matchinfo;
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struct cgroup *cgrp;
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if ((info->invert_path & ~1) || (info->invert_classid & ~1))
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return -EINVAL;
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if (!info->has_path && !info->has_classid) {
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pr_info("xt_cgroup: no path or classid specified\n");
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return -EINVAL;
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}
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if (info->has_path && info->has_classid) {
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pr_info_ratelimited("path and classid specified\n");
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return -EINVAL;
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}
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info->priv = NULL;
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if (info->has_path) {
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cgrp = cgroup_get_from_path(info->path);
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if (IS_ERR(cgrp)) {
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pr_info_ratelimited("invalid path, errno=%ld\n",
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PTR_ERR(cgrp));
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return -EINVAL;
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}
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info->priv = cgrp;
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}
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return 0;
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}
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static bool
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cgroup_mt_v0(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_cgroup_info_v0 *info = par->matchinfo;
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struct sock *sk = skb->sk;
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if (!sk || !sk_fullsock(sk) || !net_eq(xt_net(par), sock_net(sk)))
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return false;
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return (info->id == sock_cgroup_classid(&skb->sk->sk_cgrp_data)) ^
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info->invert;
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}
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static bool cgroup_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_cgroup_info_v1 *info = par->matchinfo;
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struct sock_cgroup_data *skcd = &skb->sk->sk_cgrp_data;
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struct cgroup *ancestor = info->priv;
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struct sock *sk = skb->sk;
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if (!sk || !sk_fullsock(sk) || !net_eq(xt_net(par), sock_net(sk)))
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return false;
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if (ancestor)
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return cgroup_is_descendant(sock_cgroup_ptr(skcd), ancestor) ^
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info->invert_path;
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else
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return (info->classid == sock_cgroup_classid(skcd)) ^
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info->invert_classid;
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}
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static void cgroup_mt_destroy_v1(const struct xt_mtdtor_param *par)
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{
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struct xt_cgroup_info_v1 *info = par->matchinfo;
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if (info->priv)
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cgroup_put(info->priv);
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}
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static struct xt_match cgroup_mt_reg[] __read_mostly = {
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{
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.name = "cgroup",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.checkentry = cgroup_mt_check_v0,
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.match = cgroup_mt_v0,
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.matchsize = sizeof(struct xt_cgroup_info_v0),
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.me = THIS_MODULE,
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.hooks = (1 << NF_INET_LOCAL_OUT) |
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(1 << NF_INET_POST_ROUTING) |
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(1 << NF_INET_LOCAL_IN),
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},
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{
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.name = "cgroup",
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.revision = 1,
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.family = NFPROTO_UNSPEC,
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.checkentry = cgroup_mt_check_v1,
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.match = cgroup_mt_v1,
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.matchsize = sizeof(struct xt_cgroup_info_v1),
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.usersize = offsetof(struct xt_cgroup_info_v1, priv),
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.destroy = cgroup_mt_destroy_v1,
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.me = THIS_MODULE,
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.hooks = (1 << NF_INET_LOCAL_OUT) |
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(1 << NF_INET_POST_ROUTING) |
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(1 << NF_INET_LOCAL_IN),
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},
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};
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static int __init cgroup_mt_init(void)
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{
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return xt_register_matches(cgroup_mt_reg, ARRAY_SIZE(cgroup_mt_reg));
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}
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static void __exit cgroup_mt_exit(void)
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{
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xt_unregister_matches(cgroup_mt_reg, ARRAY_SIZE(cgroup_mt_reg));
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}
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module_init(cgroup_mt_init);
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module_exit(cgroup_mt_exit);
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