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libnet/d/bridge: Allow IPv6 ICC from any IP address

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IPv6 ipt rules are exactly the same as IPv4 rules, although both
protocol don't use the same networking model. This has bad consequences,
for instance: 1. the current v6 rules disallow Neighbor
Solication/Advertisement ; 2. multicast addresses can't be used ; 3.
link-local addresses are blocked too.

To solve this, this commit changes the following rules:

```
-A DOCKER-ISOLATION-STAGE-1 ! -s fdf1:a844:380c:b247::/64 -o br-21502e5b2c6c -j DROP
-A DOCKER-ISOLATION-STAGE-1 ! -d fdf1:a844:380c:b247::/64 -i br-21502e5b2c6c -j DROP
```

into:

```
-A DOCKER-ISOLATION-STAGE-1 ! -s fdf1:a844:380c:b247::/64 ! -i br-21502e5b2c6c   -o br-21502e5b2c6c -j DROP
-A DOCKER-ISOLATION-STAGE-1 ! -d fdf1:a844:380c:b247::/64   -i br-21502e5b2c6c ! -o br-21502e5b2c6c -j DROP
```

These rules only limit the traffic ingressing/egressing the bridge, but
not traffic between veth on the same bridge.

Note that, the Kernel takes care of dropping invalid IPv6 packets, eg.
loopback spoofing, thus these rules don't need to be more specific.

Solve #45460.

Signed-off-by: Albin Kerouanton <albinker@gmail.com>
This commit is contained in:
Albin Kerouanton 2023-05-30 14:23:02 +02:00
parent 098b0fd1a0
commit da9e44a620
No known key found for this signature in database
GPG key ID: 630B8E1DCBDB1864
1 changed files with 14 additions and 7 deletions
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21
libnetwork/drivers/bridge/setup_ip_tables.go
View file

@ -396,15 +396,21 @@ func removeIPChains(version iptables.IPVersion) {
}
func setupInternalNetworkRules(bridgeIface string, addr *net.IPNet, icc, insert bool) error {
var (
inDropRule = iptRule{table: iptables.Filter, chain: IsolationChain1, args: []string{"-i", bridgeIface, "!", "-d", addr.String(), "-j", "DROP"}}
outDropRule = iptRule{table: iptables.Filter, chain: IsolationChain1, args: []string{"-o", bridgeIface, "!", "-s", addr.String(), "-j", "DROP"}}
)
var version iptables.IPVersion
var inDropRule, outDropRule iptRule
version := iptables.IPv4
if addr.IP.To4() == nil {
if addr.IP.To4() != nil {
version = iptables.IPv4
inDropRule = iptRule{table: iptables.Filter, chain: IsolationChain1, args: []string{
"-i", bridgeIface, "!", "-d", addr.String(), "-j", "DROP"}}
outDropRule = iptRule{table: iptables.Filter, chain: IsolationChain1, args: []string{
"-o", bridgeIface, "!", "-s", addr.String(), "-j", "DROP"}}
} else {
version = iptables.IPv6
inDropRule = iptRule{table: iptables.Filter, chain: IsolationChain1, args: []string{
"-i", bridgeIface, "!", "-o", bridgeIface, "!", "-d", addr.String(), "-j", "DROP"}}
outDropRule = iptRule{table: iptables.Filter, chain: IsolationChain1, args: []string{
"!", "-i", bridgeIface, "-o", bridgeIface, "!", "-s", addr.String(), "-j", "DROP"}}
}
if err := programChainRule(version, inDropRule, "DROP INCOMING", insert); err != nil {
@ -413,6 +419,7 @@ func setupInternalNetworkRules(bridgeIface string, addr *net.IPNet, icc, insert
if err := programChainRule(version, outDropRule, "DROP OUTGOING", insert); err != nil {
return err
}
// Set Inter Container Communication.
return setIcc(version, bridgeIface, icc, insert)
}