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| author | Phil Sutter <phil@nwl.cc> | 2023-02-03 17:37:40 +0100 |
|---|---|---|
| committer | Phil Sutter <phil@nwl.cc> | 2023-02-17 18:18:48 +0100 |
| commit | b860e658200af8fdeced2896a1a6c2f0f0692b70 (patch) | |
| tree | 146f8d8c9cf7c5c57afe827ab6b8214e9e161b8b | |
| parent | 744c56bda974caaa274318d2825b3e43b55bf145 (diff) | |
| download | iptables-b860e658200af8fdeced2896a1a6c2f0f0692b70.tar.gz | |
extensions: libebt_ip: Translation has to match on ether type
On one hand, nft refuses th expression in bridge family if layer3
protocol has not been assured by a previous match. On the other, ebt_ip
kernel module will only match on IPv4 packets, so there might be a
functional change in the translation versus the original.
Instead of just always emitting an 'ether type' match, decide whether
it's actually needed - explicit "ip <something>" payload matches (or
icmp ones) cause implicit creation of a match on IPv4 by nft.
Fixes: 03ecffe6c2cc0 ("ebtables-compat: add initial translations")
Signed-off-by: Phil Sutter <phil@nwl.cc>
| -rw-r--r-- | extensions/libebt_ip.c | 21 | ||||
| -rw-r--r-- | extensions/libebt_ip.txlate | 6 |
2 files changed, 24 insertions, 3 deletions
diff --git a/extensions/libebt_ip.c b/extensions/libebt_ip.c index 8b381aa1..68f34bff 100644 --- a/extensions/libebt_ip.c +++ b/extensions/libebt_ip.c @@ -432,6 +432,24 @@ static void brip_xlate_nh(struct xt_xlate *xl, xtables_ipmask_to_numeric(maskp)); } +static bool may_skip_ether_type_dep(uint8_t flags) +{ + /* these convert to "ip (s|d)addr" matches */ + if (flags & (EBT_IP_SOURCE | EBT_IP_DEST)) + return true; + + /* icmp match triggers implicit ether type dependency in nft */ + if (flags & EBT_IP_ICMP) + return true; + + /* allow if "ip protocol" match is created by brip_xlate() */ + if (flags & EBT_IP_PROTO && + !(flags & (EBT_IP_SPORT | EBT_IP_DPORT | EBT_IP_ICMP))) + return true; + + return false; +} + static int brip_xlate(struct xt_xlate *xl, const struct xt_xlate_mt_params *params) { @@ -441,6 +459,9 @@ static int brip_xlate(struct xt_xlate *xl, brip_xlate_nh(xl, info, EBT_IP_SOURCE); brip_xlate_nh(xl, info, EBT_IP_DEST); + if (!may_skip_ether_type_dep(info->bitmask)) + xt_xlate_add(xl, "ether type ip "); + if (info->bitmask & EBT_IP_TOS) { xt_xlate_add(xl, "@nh,8,8 "); if (info->invflags & EBT_IP_TOS) diff --git a/extensions/libebt_ip.txlate b/extensions/libebt_ip.txlate index 562e3157..28996832 100644 --- a/extensions/libebt_ip.txlate +++ b/extensions/libebt_ip.txlate @@ -5,13 +5,13 @@ ebtables-translate -I FORWARD -p ip --ip-dst 10.0.0.1 nft 'insert rule bridge filter FORWARD ip daddr 10.0.0.1 counter' ebtables-translate -I OUTPUT 3 -p ip -o eth0 --ip-tos 0xff -nft 'insert rule bridge filter OUTPUT oifname "eth0" @nh,8,8 0xff counter' +nft 'insert rule bridge filter OUTPUT oifname "eth0" ether type ip @nh,8,8 0xff counter' ebtables-translate -A FORWARD -p ip --ip-proto tcp --ip-dport 22 -nft 'add rule bridge filter FORWARD tcp dport 22 counter' +nft 'add rule bridge filter FORWARD ether type ip tcp dport 22 counter' ebtables-translate -A FORWARD -p ip --ip-proto udp --ip-sport 1024:65535 -nft 'add rule bridge filter FORWARD udp sport 1024-65535 counter' +nft 'add rule bridge filter FORWARD ether type ip udp sport 1024-65535 counter' ebtables-translate -A FORWARD -p ip --ip-proto 253 nft 'add rule bridge filter FORWARD ip protocol 253 counter' |