github/kubernetes
1
0
Fork 0
mirror of https://github.com/k3s-io/kubernetes.git synced 2025-07-27 21:47:07 +00:00
Code Issues Projects Releases Wiki Activity

Merge pull request #91569 from squeed/block-localnet

Browse Source 
kubelet: block non-forwarded packets from crossing the localhost boundary
This commit is contained in:
Kubernetes Prow Robot 2020-06-01 13:10:28 -07:00 committed by GitHub
commit 5bcc33ee94
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 16 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
pkg/kubelet/kubelet_network_linux.go
View File

@ -77,6 +77,22 @@ func (kl *Kubelet) syncNetworkUtil() {
klog.Errorf("Failed to ensure rule to drop packet marked by %v in %v chain %v: %v", KubeMarkDropChain, utiliptables.TableFilter, KubeFirewallChain, err) klog.Errorf("Failed to ensure rule to drop packet marked by %v in %v chain %v: %v", KubeMarkDropChain, utiliptables.TableFilter, KubeFirewallChain, err)
return return
} }
// drop all non-local packets to localhost if they're not part of an existing
// forwarded connection. See #90259
if !kl.iptClient.IsIPv6() { // ipv6 doesn't have this issue
if _, err := kl.iptClient.EnsureRule(utiliptables.Append, utiliptables.TableFilter, KubeFirewallChain,
"-m", "comment", "--comment", "block incoming localnet connections",
"--dst", "127.0.0.0/8",
"!", "--src", "127.0.0.0/8",
"-m", "conntrack",
"!", "--ctstate", "RELATED,ESTABLISHED,DNAT",
"-j", "DROP"); err != nil {
klog.Errorf("Failed to ensure rule to drop invalid localhost packets in %v chain %v: %v", utiliptables.TableFilter, KubeFirewallChain, err)
return
}
}
if _, err := kl.iptClient.EnsureRule(utiliptables.Prepend, utiliptables.TableFilter, utiliptables.ChainOutput, "-j", string(KubeFirewallChain)); err != nil { if _, err := kl.iptClient.EnsureRule(utiliptables.Prepend, utiliptables.TableFilter, utiliptables.ChainOutput, "-j", string(KubeFirewallChain)); err != nil {
klog.Errorf("Failed to ensure that %s chain %s jumps to %s: %v", utiliptables.TableFilter, utiliptables.ChainOutput, KubeFirewallChain, err) klog.Errorf("Failed to ensure that %s chain %s jumps to %s: %v", utiliptables.TableFilter, utiliptables.ChainOutput, KubeFirewallChain, err)
return return