Secure BGP sessions
Use BGP passwords to prevent attackers from injecting false routing information.
Setting a password on a BGP peering between BGP speakers means that a peering will only work when both ends of the peering have the same password. This provides a layer of defense against an attacker impersonating an external BGP peer or a workload in the cluster, for example in order to inject malicious routing information into the cluster.
This how-to guide uses the following Calico features:
- BGPPeer with password field
Password protection on BGP sessions
Password protection is a standardized optional feature of BGP sessions. The effect is that the two peers at either end of a BGP session can only communicate, and exchange routing information, if they are both configured with the same password.
Please note that password use does not cause the data exchange to be encrypted. It remains relatively easy to eavesdrop on the data exchange, but not to inject false information.
Using Kubernetes secrets to store passwords
In Kubernetes, the Secret resource is designed for holding sensitive information, including passwords. Therefore, for this Calico feature, we use Secrets to store BGP passwords.
To use a password on a BGP peering:
Create (or update) a Kubernetes secret in the namespace where calico-node is running, so that it has a key whose value is the desired password. Note the secret name and the key name.
Note: BGP passwords must be 80 characters or fewer. If a password longer than that is configured, the BGP sessions with that password will fail to be established.
Ensure that calico-node has RBAC permissions to access that secret.
Specify the secret and key name on the relevant BGPPeer resource.
Create or update Kubernetes secret
kubectl create -f - <<EOF apiVersion: v1 kind: Secret metadata: name: bgp-secrets namespace: calico-system type: Opaque stringData: rr-password: very-secret EOF
Note: If calico-node in your cluster is running in a namespace other than calico-system, you should create the secret in that namespace instead of in calico-system.
To use this password below in a BGPPeer resource, you need to note the secret name
bgp-secrets and key name
Ensure RBAC permissions
The calico-node pod must have permission to access that secret. To allow calico-node to access that secret, you would configure:
kubectl create -f - <<EOF apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: secret-access namespace: calico-system rules: - apiGroups: [""] resources: ["secrets"] resourceNames: ["bgp-secrets"] verbs: ["watch", "list", "get"] --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: secret-access namespace: calico-system roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: secret-access subjects: - kind: ServiceAccount name: calico-node namespace: calico-system EOF
Specify secret and key name on the BGP resource
The BGP password can be specified on separate resources depending on the use case. Specify the password on the BGP peer in order to secure specific BGP peerings or specify the password in the BGP configuration in order to set the password for all intra cluster communications in a node to node mesh.
When configuring a BGP peer, include the secret and key name in the specification of the BGPPeer resource, like this:
apiVersion: projectcalico.org/v3 kind: BGPPeer metadata: name: bgppeer-global-3040 spec: peerIP: 22.214.171.124 asNumber: 64567 password: secretKeyRef: name: bgp-secrets key: rr-password
Include the secret in the default BGP configuration similar to the following:
kind: BGPConfiguration apiVersion: projectcalico.org/v3 metadata: name: default spec: logSeverityScreen: Info nodeToNodeMeshEnabled: true nodeMeshPassword: secretKeyRef: name: bgp-secrets key: rr-password
Note: Node to node mesh must be enabled in order to set node to node mesh BGP password.
Above and beyond
For more detail about the BGPPeer resource, see BGPPeer.
For more on configuring BGP peers, see configuring BGP peers.