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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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8e2f311a68
Following command: iptables -D FORWARD -m physdev ... causes connectivity loss in some setups. Reason is that iptables userspace will probe kernel for the module revision of the physdev patch, and physdev has an artificial dependency on br_netfilter (xt_physdev use makes no sense unless a br_netfilter module is loaded). This causes the "phydev" module to be loaded, which in turn enables the "call-iptables" infrastructure. bridged packets might then get dropped by the iptables ruleset. The better fix would be to change the "call-iptables" defaults to 0 and enforce explicit setting to 1, but that breaks backwards compatibility. This does the next best thing: add a request_module call to checkentry. This was a stray '-D ... -m physdev' won't activate br_netfilter anymore. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
143 lines
4.2 KiB
C
143 lines
4.2 KiB
C
/* Kernel module to match the bridge port in and
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* out device for IP packets coming into contact with a bridge. */
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/* (C) 2001-2003 Bart De Schuymer <bdschuym@pandora.be>
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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/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter_bridge.h>
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#include <linux/netfilter/xt_physdev.h>
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#include <linux/netfilter/x_tables.h>
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#include <net/netfilter/br_netfilter.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
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MODULE_DESCRIPTION("Xtables: Bridge physical device match");
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MODULE_ALIAS("ipt_physdev");
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MODULE_ALIAS("ip6t_physdev");
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static bool
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physdev_mt(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_physdev_info *info = par->matchinfo;
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const struct net_device *physdev;
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unsigned long ret;
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const char *indev, *outdev;
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/* Not a bridged IP packet or no info available yet:
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* LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if
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* the destination device will be a bridge. */
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if (!nf_bridge_info_exists(skb)) {
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/* Return MATCH if the invert flags of the used options are on */
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if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
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!(info->invert & XT_PHYSDEV_OP_BRIDGED))
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return false;
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if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
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!(info->invert & XT_PHYSDEV_OP_ISIN))
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return false;
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if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
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!(info->invert & XT_PHYSDEV_OP_ISOUT))
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return false;
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if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
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!(info->invert & XT_PHYSDEV_OP_IN))
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return false;
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if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
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!(info->invert & XT_PHYSDEV_OP_OUT))
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return false;
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return true;
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}
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physdev = nf_bridge_get_physoutdev(skb);
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outdev = physdev ? physdev->name : NULL;
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/* This only makes sense in the FORWARD and POSTROUTING chains */
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if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
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(!!outdev ^ !(info->invert & XT_PHYSDEV_OP_BRIDGED)))
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return false;
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physdev = nf_bridge_get_physindev(skb);
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indev = physdev ? physdev->name : NULL;
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if ((info->bitmask & XT_PHYSDEV_OP_ISIN &&
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(!indev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) ||
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(info->bitmask & XT_PHYSDEV_OP_ISOUT &&
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(!outdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT))))
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return false;
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if (!(info->bitmask & XT_PHYSDEV_OP_IN))
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goto match_outdev;
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if (indev) {
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ret = ifname_compare_aligned(indev, info->physindev,
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info->in_mask);
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if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN))
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return false;
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}
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match_outdev:
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if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
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return true;
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if (!outdev)
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return false;
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ret = ifname_compare_aligned(outdev, info->physoutdev, info->out_mask);
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return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT));
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}
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static int physdev_mt_check(const struct xt_mtchk_param *par)
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{
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const struct xt_physdev_info *info = par->matchinfo;
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static bool brnf_probed __read_mostly;
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if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
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info->bitmask & ~XT_PHYSDEV_OP_MASK)
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return -EINVAL;
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if (info->bitmask & (XT_PHYSDEV_OP_OUT | XT_PHYSDEV_OP_ISOUT) &&
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(!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) ||
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info->invert & XT_PHYSDEV_OP_BRIDGED) &&
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par->hook_mask & ((1 << NF_INET_LOCAL_OUT) |
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(1 << NF_INET_FORWARD) | (1 << NF_INET_POST_ROUTING))) {
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pr_info_ratelimited("--physdev-out and --physdev-is-out only supported in the FORWARD and POSTROUTING chains with bridged traffic\n");
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if (par->hook_mask & (1 << NF_INET_LOCAL_OUT))
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return -EINVAL;
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}
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if (!brnf_probed) {
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brnf_probed = true;
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request_module("br_netfilter");
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}
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return 0;
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}
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static struct xt_match physdev_mt_reg __read_mostly = {
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.name = "physdev",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.checkentry = physdev_mt_check,
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.match = physdev_mt,
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.matchsize = sizeof(struct xt_physdev_info),
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.me = THIS_MODULE,
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};
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static int __init physdev_mt_init(void)
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{
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return xt_register_match(&physdev_mt_reg);
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}
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static void __exit physdev_mt_exit(void)
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{
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xt_unregister_match(&physdev_mt_reg);
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}
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module_init(physdev_mt_init);
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module_exit(physdev_mt_exit);
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