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![Eric W. Biederman](/assets/img/avatar_default.png)
- Only allow adding matches from the initial user namespace - Add the appropriate conversion functions to handle matches against sockets in other user namespaces. Cc: Jan Engelhardt <jengelh@medozas.de> Cc: Patrick McHardy <kaber@trash.net> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
100 lines
2.8 KiB
C
100 lines
2.8 KiB
C
/*
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* Kernel module to match various things tied to sockets associated with
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* locally generated outgoing packets.
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*
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* (C) 2000 Marc Boucher <marc@mbsi.ca>
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*
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* Copyright © CC Computer Consultants GmbH, 2007 - 2008
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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/x_tables.h>
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#include <linux/netfilter/xt_owner.h>
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static int owner_check(const struct xt_mtchk_param *par)
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{
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struct xt_owner_match_info *info = par->matchinfo;
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/* For now only allow adding matches from the initial user namespace */
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if ((info->match & (XT_OWNER_UID|XT_OWNER_GID)) &&
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(current_user_ns() != &init_user_ns))
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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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owner_mt(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_owner_match_info *info = par->matchinfo;
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const struct file *filp;
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if (skb->sk == NULL || skb->sk->sk_socket == NULL)
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return (info->match ^ info->invert) == 0;
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else if (info->match & info->invert & XT_OWNER_SOCKET)
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/*
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* Socket exists but user wanted ! --socket-exists.
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* (Single ampersands intended.)
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*/
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return false;
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filp = skb->sk->sk_socket->file;
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if (filp == NULL)
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return ((info->match ^ info->invert) &
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(XT_OWNER_UID | XT_OWNER_GID)) == 0;
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if (info->match & XT_OWNER_UID) {
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kuid_t uid_min = make_kuid(&init_user_ns, info->uid_min);
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kuid_t uid_max = make_kuid(&init_user_ns, info->uid_max);
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if ((uid_gte(filp->f_cred->fsuid, uid_min) &&
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uid_lte(filp->f_cred->fsuid, uid_max)) ^
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!(info->invert & XT_OWNER_UID))
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return false;
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}
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if (info->match & XT_OWNER_GID) {
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kgid_t gid_min = make_kgid(&init_user_ns, info->gid_min);
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kgid_t gid_max = make_kgid(&init_user_ns, info->gid_max);
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if ((gid_gte(filp->f_cred->fsgid, gid_min) &&
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gid_lte(filp->f_cred->fsgid, gid_max)) ^
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!(info->invert & XT_OWNER_GID))
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return false;
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}
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return true;
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}
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static struct xt_match owner_mt_reg __read_mostly = {
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.name = "owner",
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.revision = 1,
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.family = NFPROTO_UNSPEC,
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.checkentry = owner_check,
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.match = owner_mt,
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.matchsize = sizeof(struct xt_owner_match_info),
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.hooks = (1 << NF_INET_LOCAL_OUT) |
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(1 << NF_INET_POST_ROUTING),
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.me = THIS_MODULE,
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};
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static int __init owner_mt_init(void)
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{
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return xt_register_match(&owner_mt_reg);
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}
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static void __exit owner_mt_exit(void)
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{
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xt_unregister_match(&owner_mt_reg);
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}
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module_init(owner_mt_init);
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module_exit(owner_mt_exit);
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MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
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MODULE_DESCRIPTION("Xtables: socket owner matching");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("ipt_owner");
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MODULE_ALIAS("ip6t_owner");
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