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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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afb7718016
While originally only being intended for outgoing traffic, commita00e76349f
("netfilter: x_tables: allow to use cgroup match for LOCAL_IN nf hooks") enabled xt_cgroups for the NF_INET_LOCAL_IN hook as well, in order to allow for nfacct accounting. Besides being currently limited to early demuxes only, commita00e76349f
forgot to add a check if we deal with full sockets, i.e. in this case not with time wait sockets. TCP time wait sockets do not have the same memory layout as full sockets, a lower memory footprint and consequently also don't have a sk_classid member; probing for sk_classid member there could potentially lead to a crash. Fixes:a00e76349f
("netfilter: x_tables: allow to use cgroup match for LOCAL_IN nf hooks") Cc: Alexey Perevalov <a.perevalov@samsung.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
72 lines
1.9 KiB
C
72 lines
1.9 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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#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(const struct xt_mtchk_param *par)
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{
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struct xt_cgroup_info *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 bool
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cgroup_mt(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_cgroup_info *info = par->matchinfo;
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if (skb->sk == NULL || !sk_fullsock(skb->sk))
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return false;
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return (info->id == skb->sk->sk_classid) ^ info->invert;
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}
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static struct xt_match cgroup_mt_reg __read_mostly = {
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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,
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.match = cgroup_mt,
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.matchsize = sizeof(struct xt_cgroup_info),
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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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static int __init cgroup_mt_init(void)
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{
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return xt_register_match(&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_match(&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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