86 lines
3.2 KiB
Diff
86 lines
3.2 KiB
Diff
From 1429ad5300d85ae9e3f6114f609afb1ac6808c71 Mon Sep 17 00:00:00 2001
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From: Phil Sutter <phil@nwl.cc>
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Date: Fri, 3 Feb 2023 17:37:40 +0100
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Subject: [PATCH] extensions: libebt_ip: Translation has to match on ether type
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On one hand, nft refuses th expression in bridge family if layer3
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protocol has not been assured by a previous match. On the other, ebt_ip
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kernel module will only match on IPv4 packets, so there might be a
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functional change in the translation versus the original.
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Instead of just always emitting an 'ether type' match, decide whether
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it's actually needed - explicit "ip <something>" payload matches (or
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icmp ones) cause implicit creation of a match on IPv4 by nft.
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Fixes: 03ecffe6c2cc0 ("ebtables-compat: add initial translations")
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Signed-off-by: Phil Sutter <phil@nwl.cc>
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(cherry picked from commit b860e658200af8fdeced2896a1a6c2f0f0692b70)
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---
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extensions/libebt_ip.c | 21 +++++++++++++++++++++
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extensions/libebt_ip.txlate | 6 +++---
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2 files changed, 24 insertions(+), 3 deletions(-)
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diff --git a/extensions/libebt_ip.c b/extensions/libebt_ip.c
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index 8b381aa10b5b7..68f34bff97deb 100644
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--- a/extensions/libebt_ip.c
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+++ b/extensions/libebt_ip.c
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@@ -432,6 +432,24 @@ static void brip_xlate_nh(struct xt_xlate *xl,
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xtables_ipmask_to_numeric(maskp));
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}
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+static bool may_skip_ether_type_dep(uint8_t flags)
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+{
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+ /* these convert to "ip (s|d)addr" matches */
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+ if (flags & (EBT_IP_SOURCE | EBT_IP_DEST))
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+ return true;
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+
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+ /* icmp match triggers implicit ether type dependency in nft */
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+ if (flags & EBT_IP_ICMP)
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+ return true;
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+
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+ /* allow if "ip protocol" match is created by brip_xlate() */
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+ if (flags & EBT_IP_PROTO &&
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+ !(flags & (EBT_IP_SPORT | EBT_IP_DPORT | EBT_IP_ICMP)))
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+ return true;
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+
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+ return false;
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+}
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+
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static int brip_xlate(struct xt_xlate *xl,
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const struct xt_xlate_mt_params *params)
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{
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@@ -441,6 +459,9 @@ static int brip_xlate(struct xt_xlate *xl,
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brip_xlate_nh(xl, info, EBT_IP_SOURCE);
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brip_xlate_nh(xl, info, EBT_IP_DEST);
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+ if (!may_skip_ether_type_dep(info->bitmask))
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+ xt_xlate_add(xl, "ether type ip ");
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+
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if (info->bitmask & EBT_IP_TOS) {
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xt_xlate_add(xl, "@nh,8,8 ");
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if (info->invflags & EBT_IP_TOS)
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diff --git a/extensions/libebt_ip.txlate b/extensions/libebt_ip.txlate
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index 562e3157d7b92..28996832225cb 100644
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--- a/extensions/libebt_ip.txlate
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+++ b/extensions/libebt_ip.txlate
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@@ -5,13 +5,13 @@ ebtables-translate -I FORWARD -p ip --ip-dst 10.0.0.1
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nft 'insert rule bridge filter FORWARD ip daddr 10.0.0.1 counter'
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ebtables-translate -I OUTPUT 3 -p ip -o eth0 --ip-tos 0xff
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-nft 'insert rule bridge filter OUTPUT oifname "eth0" @nh,8,8 0xff counter'
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+nft 'insert rule bridge filter OUTPUT oifname "eth0" ether type ip @nh,8,8 0xff counter'
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ebtables-translate -A FORWARD -p ip --ip-proto tcp --ip-dport 22
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-nft 'add rule bridge filter FORWARD tcp dport 22 counter'
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+nft 'add rule bridge filter FORWARD ether type ip tcp dport 22 counter'
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ebtables-translate -A FORWARD -p ip --ip-proto udp --ip-sport 1024:65535
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-nft 'add rule bridge filter FORWARD udp sport 1024-65535 counter'
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+nft 'add rule bridge filter FORWARD ether type ip udp sport 1024-65535 counter'
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ebtables-translate -A FORWARD -p ip --ip-proto 253
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nft 'add rule bridge filter FORWARD ip protocol 253 counter'
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--
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2.40.0
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