adjusted key derivation logic to happen in the join client

bootstrapper/internal/joinclient/BUILD.bazel

@@ -21,6 +21,7 @@ go_library(
         "@io_k8s_kubernetes//cmd/kubeadm/app/constants",
         "@io_k8s_utils//clock",
         "@org_golang_google_grpc//:grpc",
+        "@org_golang_x_crypto//ssh",
     ],
 )
 

bootstrapper/internal/joinclient/joinclient.go

@@ -18,7 +18,9 @@ If the JoinClient finds an existing cluster, it will attempt to join it as eithe
 package joinclient
 
 import (
+	"bytes"
 	"context"
+	"crypto/ed25519"
 	"errors"
 	"fmt"
 	"log/slog"
@@ -37,6 +39,7 @@ import (
 	"github.com/edgelesssys/constellation/v2/internal/versions/components"
 	"github.com/edgelesssys/constellation/v2/joinservice/joinproto"
 	"github.com/spf13/afero"
+	"golang.org/x/crypto/ssh"
 	"google.golang.org/grpc"
 	kubeadm "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
 	kubeconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
@@ -270,8 +273,19 @@ func (c *JoinClient) startNodeAndJoin(ticket *joinproto.IssueJoinTicketResponse,
 	if err := c.fileHandler.Write(certificate.KeyFilename, kubeletKey, file.OptMkdirAll); err != nil {
 		return fmt.Errorf("writing kubelet key: %w", err)
 	}
+
+	// derive CA key from emergency key
+	_, priv, err := ed25519.GenerateKey(bytes.NewReader(ticket.EmergencyCaKey))
+	if err != nil {
+		return fmt.Errorf("deriving ed25519 ssh emergency key: %w", err)
+	}
+	ca, err := ssh.NewSignerFromSigner(priv)
+	if err != nil {
+		return fmt.Errorf("creating emergency SSH CA key: %w", err)
+	}
+
 	// TODO(miampf): Make path a constant
-	if err := c.fileHandler.Write("/run/ssh/ssh_ca.pub", ticket.EmergencyCaKey, file.OptMkdirAll); err != nil {
+	if err := c.fileHandler.Write("/run/ssh/ssh_ca.pub", ssh.MarshalAuthorizedKey(ca.PublicKey()), file.OptMkdirAll); err != nil {
 		return fmt.Errorf("writing ca key: %w", err)
 	}
 

joinservice/internal/server/server.go

@@ -100,6 +100,13 @@ func (s *Server) IssueJoinTicket(ctx context.Context, req *joinproto.IssueJoinTi
 		return nil, status.Errorf(codes.Internal, "getting key for stateful disk: %s", err)
 	}
 
+	log.Info("Requesting emergency SSH CA derivation key")
+	sshCAKey, err := s.dataKeyGetter.GetDataKey(ctx, constants.SSHCAKeySuffix, 256)
+	if err != nil {
+		log.With(slog.Any("error", err)).Error("Failed to get emergency SSH CA derivation key")
+		return nil, status.Errorf(codes.Internal, "getting emergency SSH CA derivation key: %s", err)
+	}
+
 	log.Info("Creating Kubernetes join token")
 	kubeArgs, err := s.joinTokenGetter.GetJoinToken(constants.KubernetesJoinTokenTTL)
 	if err != nil {
@@ -167,6 +174,7 @@ func (s *Server) IssueJoinTicket(ctx context.Context, req *joinproto.IssueJoinTi
 		KubeletCert:              kubeletCert,
 		ControlPlaneFiles:        controlPlaneFiles,
 		KubernetesComponents:     components,
+		EmergencyCaKey:           sshCAKey,
 	}, nil
 }
 

keyservice/internal/server/BUILD.bazel

@@ -15,7 +15,6 @@ go_library(
         "@org_golang_google_grpc//:grpc",
         "@org_golang_google_grpc//codes",
         "@org_golang_google_grpc//status",
-        "@org_golang_x_crypto//ssh",
     ],
 )
 

keyservice/internal/server/server.go

@@ -8,9 +8,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 package server
 
 import (
-	"bytes"
 	"context"
-	"crypto/ed25519"
 	"fmt"
 	"log/slog"
 	"net"
@@ -20,7 +18,6 @@ import (
 	"github.com/edgelesssys/constellation/v2/internal/kms/kms"
 	"github.com/edgelesssys/constellation/v2/internal/logger"
 	"github.com/edgelesssys/constellation/v2/keyservice/keyserviceproto"
-	"golang.org/x/crypto/ssh"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
@@ -85,27 +82,3 @@ func (s *Server) GetDataKey(ctx context.Context, in *keyserviceproto.GetDataKeyR
 	}
 	return &keyserviceproto.GetDataKeyResponse{DataKey: key}, nil
 }
-
-// GetCAKey returns the CA key.
-func (s *Server) GetCAKey(ctx context.Context, in *keyserviceproto.GetCAKeyRequest) (*keyserviceproto.GetCAKeyResponse, error) {
-	log := s.log.With("peerAddress", grpclog.PeerAddrFromContext(ctx))
-
-	key, err := s.conKMS.GetDEK(ctx, crypto.DEKPrefix, 256)
-	if err != nil {
-		log.With(slog.Any("error", err)).Error("Failed to get key for derivation")
-		return nil, status.Errorf(codes.Internal, "%v", err)
-	}
-
-	_, priv, err := ed25519.GenerateKey(bytes.NewReader(key))
-	if err != nil {
-		log.With(slog.Any("error", err)).Error("Failed to generate ed25519 key")
-		return nil, status.Errorf(codes.Internal, "%v", err)
-	}
-
-	ca, err := ssh.NewSignerFromKey(priv)
-	if err != nil {
-		log.With(slog.Any("error", err)).Error("Failed to generate CA key")
-		return nil, status.Errorf(codes.Internal, "%v", err)
-	}
-	return &keyserviceproto.GetCAKeyResponse{CaKey: ssh.MarshalAuthorizedKey(ca.PublicKey())}, nil
-}

keyservice/keyserviceproto/keyservice.proto

@@ -4,22 +4,11 @@ package kms;
 
 option go_package = "github.com/edgelesssys/constellation/v2/keyservice/keyserviceproto";
 
-service API {
+service API { rpc GetDataKey(GetDataKeyRequest) returns (GetDataKeyResponse); }
-  rpc GetDataKey(GetDataKeyRequest) returns (GetDataKeyResponse);
-  rpc GetCAKey(GetCAKeyRequest) returns (GetCAKeyResponse);
-}
 
 message GetDataKeyRequest {
   string data_key_id = 1;
   uint32 length = 2;
 }
 
-message GetDataKeyResponse {
+message GetDataKeyResponse { bytes data_key = 1; }
-  bytes data_key = 1;
-}
-
-message GetCAKeyRequest {}
-
-message GetCAKeyResponse {
-  bytes ca_key = 1;
-}