constellation/internal/attestation/gcp/validator_test.go

/*
Copyright (c) Edgeless Systems GmbH

SPDX-License-Identifier: AGPL-3.0-only
*/

package gcp

import (
	"context"
	"crypto/rsa"
	"encoding/json"
	"errors"
	"testing"

	"cloud.google.com/go/compute/apiv1/computepb"
	"github.com/edgelesssys/constellation/v2/internal/attestation/vtpm"
	"github.com/google/go-tpm-tools/proto/attest"
	"github.com/googleapis/gax-go/v2"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"google.golang.org/api/option"
	"google.golang.org/protobuf/proto"
)

func TestValidateCVM(t *testing.T) {
	testCases := map[string]struct {
		state   *attest.MachineState
		wantErr bool
	}{
		"is current cvm": {
			state: &attest.MachineState{Platform: &attest.PlatformState{
				Firmware:   &attest.PlatformState_GceVersion{GceVersion: minimumGceVersion},
				Technology: attest.GCEConfidentialTechnology_AMD_SEV,
			}},
		},
		"is newer cvm": {
			state: &attest.MachineState{Platform: &attest.PlatformState{
				Firmware:   &attest.PlatformState_GceVersion{GceVersion: minimumGceVersion + 1},
				Technology: attest.GCEConfidentialTechnology_AMD_SEV,
			}},
		},
		"is older cvm": {
			state: &attest.MachineState{Platform: &attest.PlatformState{
				Firmware:   &attest.PlatformState_GceVersion{GceVersion: minimumGceVersion - 1},
				Technology: attest.GCEConfidentialTechnology_AMD_SEV,
			}},
			wantErr: true,
		},
		"not a cvm": {
			state: &attest.MachineState{Platform: &attest.PlatformState{
				Firmware:   &attest.PlatformState_GceVersion{GceVersion: minimumGceVersion},
				Technology: attest.GCEConfidentialTechnology_NONE,
			}},
			wantErr: true,
		},
	}

	for name, tc := range testCases {
		t.Run(name, func(t *testing.T) {
			assert := assert.New(t)
			err := validateCVM(vtpm.AttestationDocument{}, tc.state)
			if tc.wantErr {
				assert.Error(err)
			} else {
				assert.NoError(err)
			}
		})
	}
}

func TestTrustedKeyFromGCEAPI(t *testing.T) {
	testPubK := `-----BEGIN PUBLIC KEY-----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-----END PUBLIC KEY-----`

	testCases := map[string]struct {
		instanceInfo []byte
		getClient    func(ctx context.Context, opts ...option.ClientOption) (gcpRestClient, error)
		wantErr      bool
	}{
		"success": {
			instanceInfo: mustMarshal(&attest.GCEInstanceInfo{}, require.New(t)),
			getClient: prepareFakeClient(&computepb.ShieldedInstanceIdentity{
				SigningKey: &computepb.ShieldedInstanceIdentityEntry{
					EkPub: proto.String(testPubK),
				},
			}, nil, nil),
			wantErr: false,
		},
		"Unmarshal error": {
			instanceInfo: []byte("error"),
			getClient: prepareFakeClient(&computepb.ShieldedInstanceIdentity{
				SigningKey: &computepb.ShieldedInstanceIdentityEntry{
					EkPub: proto.String(testPubK),
				},
			}, nil, nil),
			wantErr: true,
		},
		"empty signing key": {
			instanceInfo: mustMarshal(&attest.GCEInstanceInfo{}, require.New(t)),
			getClient:    prepareFakeClient(&computepb.ShieldedInstanceIdentity{}, nil, nil),
			wantErr:      true,
		},
		"new client error": {
			instanceInfo: mustMarshal(&attest.GCEInstanceInfo{}, require.New(t)),
			getClient: prepareFakeClient(&computepb.ShieldedInstanceIdentity{
				SigningKey: &computepb.ShieldedInstanceIdentityEntry{
					EkPub: proto.String(testPubK),
				},
			}, errors.New("error"), nil),
			wantErr: true,
		},
		"GetShieldedInstanceIdentity error": {
			instanceInfo: mustMarshal(&attest.GCEInstanceInfo{}, require.New(t)),
			getClient: prepareFakeClient(&computepb.ShieldedInstanceIdentity{
				SigningKey: &computepb.ShieldedInstanceIdentityEntry{
					EkPub: proto.String(testPubK),
				},
			}, nil, errors.New("error")),
			wantErr: true,
		},
		"Decode error": {
			instanceInfo: mustMarshal(&attest.GCEInstanceInfo{}, require.New(t)),
			getClient: prepareFakeClient(&computepb.ShieldedInstanceIdentity{
				SigningKey: &computepb.ShieldedInstanceIdentityEntry{
					EkPub: proto.String("Not a public key"),
				},
			}, nil, nil),
			wantErr: true,
		},
	}

	for name, tc := range testCases {
		t.Run(name, func(t *testing.T) {
			assert := assert.New(t)

			v := &Validator{
				restClient: tc.getClient,
			}
			attDoc := vtpm.AttestationDocument{InstanceInfo: tc.instanceInfo}

			out, err := v.trustedKeyFromGCEAPI(context.Background(), attDoc, nil)

			if tc.wantErr {
				assert.Error(err)
			} else {
				assert.NoError(err)
				_, ok := out.(*rsa.PublicKey)
				assert.True(ok)
			}
		})
	}
}

func mustMarshal(in *attest.GCEInstanceInfo, require *require.Assertions) []byte {
	out, err := json.Marshal(in)
	require.NoError(err)
	return out
}

type fakeInstanceClient struct {
	getIdentErr error
	ident       *computepb.ShieldedInstanceIdentity
}

func prepareFakeClient(ident *computepb.ShieldedInstanceIdentity, newErr, getIdentErr error) func(ctx context.Context, opts ...option.ClientOption) (gcpRestClient, error) {
	return func(_ context.Context, _ ...option.ClientOption) (gcpRestClient, error) {
		return &fakeInstanceClient{
			getIdentErr: getIdentErr,
			ident:       ident,
		}, newErr
	}
}

func (c *fakeInstanceClient) Close() error {
	return nil
}

func (c *fakeInstanceClient) GetShieldedInstanceIdentity(_ context.Context, _ *computepb.GetShieldedInstanceIdentityInstanceRequest, _ ...gax.CallOption) (*computepb.ShieldedInstanceIdentity, error) {
	return c.ident, c.getIdentErr
}