constellation/internal/watcher/validator.go
Otto Bittner 405db3286e AB#2386: TrustedLaunch support for azure attestation
* There are now two attestation packages on azure.
The issuer on the server side is created base on successfully
querying the idkeydigest from the TPM. Fallback on err: Trusted Launch.
* The bootstrapper's issuer choice is validated by the CLI's validator,
which is created based on the local config.
* Add "azureCVM" field to new "internal-config" cm.
This field is populated by the bootstrapper.
* Group attestation OIDs by CSP (#42)
* Bootstrapper now uses IssuerWrapper type to pass
the issuer (and some context info) to the initserver.
* Introduce VMType package akin to cloudprovider. Used by
IssuerWrapper.
* Extend unittests.
* Remove CSP specific attestation integration tests

Co-authored-by: <dw@edgeless.systems>
Signed-off-by: Otto Bittner <cobittner@posteo.net>
2022-09-05 12:03:48 +02:00

142 lines
4.6 KiB
Go

/*
Copyright (c) Edgeless Systems GmbH
SPDX-License-Identifier: AGPL-3.0-only
*/
package watcher
import (
"encoding/asn1"
"encoding/hex"
"fmt"
"path/filepath"
"strconv"
"sync"
"github.com/edgelesssys/constellation/internal/atls"
"github.com/edgelesssys/constellation/internal/attestation/azure/snp"
"github.com/edgelesssys/constellation/internal/attestation/azure/trustedlaunch"
"github.com/edgelesssys/constellation/internal/attestation/gcp"
"github.com/edgelesssys/constellation/internal/attestation/qemu"
"github.com/edgelesssys/constellation/internal/cloud/cloudprovider"
"github.com/edgelesssys/constellation/internal/constants"
"github.com/edgelesssys/constellation/internal/file"
"github.com/edgelesssys/constellation/internal/logger"
)
// Updatable implements an updatable atls.Validator.
type Updatable struct {
log *logger.Logger
mux sync.Mutex
newValidator newValidatorFunc
fileHandler file.Handler
csp cloudprovider.Provider
azureCVM bool
atls.Validator
}
// NewValidator initializes a new updatable validator.
func NewValidator(log *logger.Logger, csp string, fileHandler file.Handler, azureCVM bool) (*Updatable, error) {
var newValidator newValidatorFunc
switch cloudprovider.FromString(csp) {
case cloudprovider.Azure:
if azureCVM {
newValidator = func(m map[uint32][]byte, e []uint32, idkeydigest []byte, enforceIdKeyDigest bool, log *logger.Logger) atls.Validator {
return snp.NewValidator(m, e, idkeydigest, enforceIdKeyDigest, log)
}
} else {
newValidator = func(m map[uint32][]byte, e []uint32, idkeydigest []byte, enforceIdKeyDigest bool, log *logger.Logger) atls.Validator {
return trustedlaunch.NewValidator(m, e, log)
}
}
case cloudprovider.GCP:
newValidator = func(m map[uint32][]byte, e []uint32, _ []byte, _ bool, log *logger.Logger) atls.Validator {
return gcp.NewValidator(m, e, log)
}
case cloudprovider.QEMU:
newValidator = func(m map[uint32][]byte, e []uint32, _ []byte, _ bool, log *logger.Logger) atls.Validator {
return qemu.NewValidator(m, e, log)
}
default:
return nil, fmt.Errorf("unknown cloud service provider: %q", csp)
}
u := &Updatable{
log: log,
newValidator: newValidator,
fileHandler: fileHandler,
csp: cloudprovider.FromString(csp),
azureCVM: azureCVM,
}
if err := u.Update(); err != nil {
return nil, err
}
return u, nil
}
// Validate calls the validators Validate method, and prevents any updates during the call.
func (u *Updatable) Validate(attDoc []byte, nonce []byte) ([]byte, error) {
u.mux.Lock()
defer u.mux.Unlock()
return u.Validator.Validate(attDoc, nonce)
}
// OID returns the validators Object Identifier.
func (u *Updatable) OID() asn1.ObjectIdentifier {
return u.Validator.OID()
}
// Update switches out the underlying validator.
func (u *Updatable) Update() error {
u.mux.Lock()
defer u.mux.Unlock()
u.log.Infof("Updating expected measurements")
var measurements map[uint32][]byte
if err := u.fileHandler.ReadJSON(filepath.Join(constants.ServiceBasePath, constants.MeasurementsFilename), &measurements); err != nil {
return err
}
u.log.Debugf("New measurements: %v", measurements)
var enforced []uint32
if err := u.fileHandler.ReadJSON(filepath.Join(constants.ServiceBasePath, constants.EnforcedPCRsFilename), &enforced); err != nil {
return err
}
u.log.Debugf("Enforced PCRs: %v", enforced)
var idkeydigest []byte
var enforceIdKeyDigest bool
if u.csp == cloudprovider.Azure && u.azureCVM {
u.log.Infof("Updating encforceIdKeyDigest value")
enforceRaw, err := u.fileHandler.Read(filepath.Join(constants.ServiceBasePath, constants.EnforceIdKeyDigestFilename))
if err != nil {
return err
}
enforceIdKeyDigest, err = strconv.ParseBool(string(enforceRaw))
if err != nil {
return fmt.Errorf("parsing content of EnforceIdKeyDigestFilename: %s: %w", enforceRaw, err)
}
u.log.Debugf("New encforceIdKeyDigest value: %v", enforceIdKeyDigest)
u.log.Infof("Updating expected idkeydigest")
idkeydigestRaw, err := u.fileHandler.Read(filepath.Join(constants.ServiceBasePath, constants.IdKeyDigestFilename))
if err != nil {
return err
}
idkeydigest, err = hex.DecodeString(string(idkeydigestRaw))
if err != nil {
return fmt.Errorf("parsing hexstring: %s: %w", idkeydigestRaw, err)
}
u.log.Debugf("New idkeydigest: %x", idkeydigest)
}
u.Validator = u.newValidator(measurements, enforced, idkeydigest, enforceIdKeyDigest, u.log)
return nil
}
type newValidatorFunc func(measurements map[uint32][]byte, enforcedPCRs []uint32, idkeydigest []byte, enforceIdKeyDigest bool, log *logger.Logger) atls.Validator