elemental-operator/pkg/server/server.go

/*
Copyright © 2022 SUSE LLC

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package server

import (
	"crypto/sha256"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"

	"github.com/pkg/errors"
	v1 "github.com/rancher-sandbox/rancheros-operator/pkg/apis/rancheros.cattle.io/v1"
	"github.com/rancher-sandbox/rancheros-operator/pkg/clients"
	ranchercontrollers "github.com/rancher-sandbox/rancheros-operator/pkg/generated/controllers/management.cattle.io/v3"
	roscontrollers "github.com/rancher-sandbox/rancheros-operator/pkg/generated/controllers/rancheros.cattle.io/v1"
	"github.com/rancher-sandbox/rancheros-operator/pkg/tpm"
	v3 "github.com/rancher/rancher/pkg/apis/management.cattle.io/v3"
	corecontrollers "github.com/rancher/wrangler/pkg/generated/controllers/core/v1"
	corev1 "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
)

var (
	tokenType                = "rancheros.cattle.io/token"
	tokenKey                 = "token"
	tokenIndex               = "tokenIndex"
	machineBySecretNameIndex = "machineBySecretNameIndex"
	registrationTokenIndex   = "registrationTokenIndex"
	tpmHashIndex             = "tpmHashIndex"
)

type authenticator interface {
	Authenticate(resp http.ResponseWriter, req *http.Request, registerNamespace string) (*v1.MachineInventory, bool, io.WriteCloser, error)
}

type InventoryServer struct {
	settingCache             ranchercontrollers.SettingCache
	secretCache              corecontrollers.SecretCache
	machineCache             roscontrollers.MachineInventoryCache
	machineClient            roscontrollers.MachineInventoryClient
	machineRegistrationCache roscontrollers.MachineRegistrationCache
	clusterRegistrationToken ranchercontrollers.ClusterRegistrationTokenCache
	authenticators           []authenticator
}

func New(clients *clients.Clients) *InventoryServer {
	server := &InventoryServer{
		authenticators: []authenticator{
			tpm.New(clients),
			newSharedSecretAuth(clients),
		},
		secretCache:              clients.Core.Secret().Cache(),
		machineCache:             clients.OS.MachineInventory().Cache(),
		machineClient:            clients.OS.MachineInventory(),
		machineRegistrationCache: clients.OS.MachineRegistration().Cache(),
		settingCache:             clients.Rancher.Setting().Cache(),
		clusterRegistrationToken: clients.Rancher.ClusterRegistrationToken().Cache(),
	}

	server.secretCache.AddIndexer(tokenHash, func(obj *corev1.Secret) ([]string, error) {
		if string(obj.Type) != tokenType {
			return nil, nil
		}
		if token := obj.Data[tokenKey]; len(token) > 0 {
			hash := sha256.Sum256(token)
			return []string{base64.StdEncoding.EncodeToString(hash[:])}, nil
		}
		return nil, nil
	})

	server.machineCache.AddIndexer(tokenHash, func(obj *v1.MachineInventory) ([]string, error) {
		if obj.Spec.TPMHash == "" {
			return nil, nil
		}
		hash := sha256.Sum256([]byte(obj.Spec.TPMHash))
		return []string{base64.StdEncoding.EncodeToString(hash[:])}, nil
	})

	server.machineRegistrationCache.AddIndexer(registrationTokenIndex, func(obj *v1.MachineRegistration) ([]string, error) {
		if obj.Status.RegistrationToken == "" {
			return nil, nil
		}
		return []string{
			obj.Status.RegistrationToken,
		}, nil
	})

	server.machineCache.AddIndexer(tpmHashIndex, func(obj *v1.MachineInventory) ([]string, error) {
		if obj.Spec.TPMHash == "" {
			return nil, nil
		}
		return []string{obj.Spec.TPMHash}, nil
	})

	return server
}

func (i *InventoryServer) ServeHTTP(resp http.ResponseWriter, req *http.Request) {
	if strings.Contains(req.URL.Path, "/registration/") {
		i.register(resp, req)
	} else if strings.HasSuffix(req.URL.Path, "/cacerts") {
		i.cacerts(resp, req)
	} else {
		i.handle(resp, req)
	}
}

func (i *InventoryServer) authMachine(resp http.ResponseWriter, req *http.Request, registerNamespace string) (*v1.MachineInventory, io.WriteCloser, error) {
	for _, auth := range i.authenticators {
		machine, cont, writer, err := auth.Authenticate(resp, req, registerNamespace)
		if err != nil {
			return nil, nil, err
		}
		if machine != nil || !cont {
			return machine, writer, nil
		}
	}
	return nil, nil, nil
}

func writeErr(writer io.Writer, resp http.ResponseWriter, err error) {
	message := "Unauthorized"
	if err != nil {
		message = err.Error()
	}
	if writer == nil {
		http.Error(resp, message, http.StatusUnauthorized)
	} else {
		_, _ = writer.Write([]byte(message))
	}
}

func (i *InventoryServer) handle(resp http.ResponseWriter, req *http.Request) {
	machine, writer, err := i.authMachine(resp, req, "")
	if machine == nil || err != nil {
		writeErr(writer, resp, err)
		return
	}
	defer writer.Close()

	if machine.Spec.ClusterName == "" {
		writeErr(writer, resp, errors.New("cluster not assigned"))
		return
	}
	crt, err := i.clusterRegistrationToken.Get(machine.Status.ClusterRegistrationTokenNamespace,
		machine.Status.ClusterRegistrationTokenName)
	if apierrors.IsNotFound(err) || crt.Status.Token == "" {
		writeErr(writer, resp, errors.New("cluster token not assigned"))
	}

	if err := writeResponse(writer, machine, crt); err != nil {
		writeErr(writer, resp, err)
	}
}

type config struct {
	Role            string   `json:"role,omitempty"`
	NodeName        string   `json:"nodeName,omitempty"`
	Address         string   `json:"address,omitempty"`
	InternalAddress string   `json:"internalAddress,omitempty"`
	Taints          []string `json:"taints,omitempty"`
	Labels          []string `json:"labels,omitempty"`
	Token           string   `json:"token,omitempty"`
}

func writeResponse(writer io.Writer, inventory *v1.MachineInventory, crt *v3.ClusterRegistrationToken) error {
	config := config{
		Role:            inventory.Spec.Config.Role,
		NodeName:        inventory.Spec.Config.NodeName,
		Address:         inventory.Spec.Config.Address,
		InternalAddress: inventory.Spec.Config.InternalAddress,
		Taints:          nil,
		Labels:          nil,
		Token:           crt.Status.Token,
	}
	for k, v := range inventory.Spec.Config.Labels {
		config.Labels = append(config.Labels, fmt.Sprintf("%s=%s", k, v))
	}
	for _, taint := range inventory.Spec.Config.Taints {
		config.Labels = append(config.Labels, taint.ToString())
	}
	return json.NewEncoder(writer).Encode(config)
}