added state manager with tests

2 files changed, 386 insertions, 33 deletions

diff --git a/state/state_manager.go b/state/state_manager.go
index 21c3eda..3199e61 100644
--- a/state/state_manager.go
+++ b/state/state_manager.go
@@ -3,7 +3,6 @@ package stfe
 import (
 	"context"
 	"crypto"
-	"crypto/ed25519"
 	"fmt"
 	"reflect"
 	"sync"
@@ -20,14 +19,14 @@ type StateManager interface {
 	Latest(context.Context) (*types.SignedTreeHead, error)
 	ToSign(context.Context) (*types.SignedTreeHead, error)
 	Cosigned(context.Context) (*types.SignedTreeHead, error)
-	AddCosignature(context.Context, ed25519.PublicKey, *[types.SignatureSize]byte) error
+	AddCosignature(context.Context, *[types.VerificationKeySize]byte, *[types.SignatureSize]byte) error
 	Run(context.Context)
 }
 
 // StateManagerSingle implements the StateManager interface.  It is assumed that
 // the log server is running on a single-instance machine.  So, no coordination.
 type StateManagerSingle struct {
-	client   *trillian.Client
+	client   trillian.Client
 	signer   crypto.Signer
 	interval time.Duration
 	deadline time.Duration
@@ -43,7 +42,7 @@ type StateManagerSingle struct {
 	cosignature map[[types.HashSize]byte]*types.SigIdent
 }
 
-func NewStateManagerSingle(client *trillian.Client, signer crypto.Signer, interval, deadline time.Duration) (*StateManagerSingle, error) {
+func NewStateManagerSingle(client trillian.Client, signer crypto.Signer, interval, deadline time.Duration) (*StateManagerSingle, error) {
 	sm := &StateManagerSingle{
 		client:   client,
 		signer:   signer,
@@ -59,7 +58,9 @@ func NewStateManagerSingle(client *trillian.Client, signer crypto.Signer, interv
 
 	sm.cosigned = *sth
 	sm.tosign = *sth
-	sm.cosignature = make(map[[types.HashSize]byte]*types.SigIdent)
+	sm.cosignature = map[[types.HashSize]byte]*types.SigIdent{
+		*sth.SigIdent[0].KeyHash: sth.SigIdent[0], // log signature
+	}
 	return sm, nil
 }
 
@@ -83,7 +84,7 @@ func (sm *StateManagerSingle) Latest(ctx context.Context) (*types.SignedTreeHead
 	if err != nil {
 		return nil, fmt.Errorf("LatestTreeHead: %v", err)
 	}
-	sth, err := sign(sm.signer, th)
+	sth, err := th.Sign(sm.signer)
 	if err != nil {
 		return nil, fmt.Errorf("sign: %v", err)
 	}
@@ -102,12 +103,12 @@ func (sm *StateManagerSingle) Cosigned(_ context.Context) (*types.SignedTreeHead
 	return &sm.cosigned, nil
 }
 
-func (sm *StateManagerSingle) AddCosignature(_ context.Context, vk ed25519.PublicKey, sig *[types.SignatureSize]byte) error {
+func (sm *StateManagerSingle) AddCosignature(_ context.Context, vk *[types.VerificationKeySize]byte, sig *[types.SignatureSize]byte) error {
 	sm.Lock()
 	defer sm.Unlock()
 
-	if msg := sm.tosign.TreeHead.Marshal(); !ed25519.Verify(vk, msg, sig[:]) {
-		return fmt.Errorf("invalid signature for tree head with timestamp: %d", sm.tosign.Timestamp)
+	if err := sm.tosign.TreeHead.Verify(vk, sig); err != nil {
+		return fmt.Errorf("Verify: %v", err)
 	}
 	witness := types.Hash(vk[:])
 	if _, ok := sm.cosignature[*witness]; ok {
@@ -126,13 +127,15 @@ func (sm *StateManagerSingle) AddCosignature(_ context.Context, vk ed25519.Publi
 // source's read-write lock if there are concurrent reads and/or writes.
 func (sm *StateManagerSingle) rotate(next *types.SignedTreeHead) {
 	if reflect.DeepEqual(sm.cosigned.TreeHead, sm.tosign.TreeHead) {
-		for _, sigident := range sm.cosigned.SigIdent[1:] { // skip log sigident
+		// cosigned and tosign are the same.  So, we need to merge all
+		// cosignatures that we already had with the new collected ones.
+		for _, sigident := range sm.cosigned.SigIdent {
 			if _, ok := sm.cosignature[*sigident.KeyHash]; !ok {
 				sm.cosignature[*sigident.KeyHash] = sigident
 			}
 		}
+		glog.V(3).Infof("cosigned tree head repeated, merged signatures")
 	}
-	// cosignatures will contain all cosignatures (even if repeated tree head)
 	var cosignatures []*types.SigIdent
 	for _, sigident := range sm.cosignature {
 		cosignatures = append(cosignatures, sigident)
@@ -140,29 +143,12 @@ func (sm *StateManagerSingle) rotate(next *types.SignedTreeHead) {
 
 	// Update cosigned tree head
 	sm.cosigned.TreeHead = sm.tosign.TreeHead
-	sm.cosigned.SigIdent = append(sm.tosign.SigIdent, cosignatures...)
+	sm.cosigned.SigIdent = cosignatures
 
 	// Update to-sign tree head
 	sm.tosign = *next
-	sm.cosignature = make(map[[types.HashSize]byte]*types.SigIdent)
-	glog.V(3).Infof("rotated sth")
-}
-
-func sign(signer crypto.Signer, th *types.TreeHead) (*types.SignedTreeHead, error) {
-	sig, err := signer.Sign(nil, th.Marshal(), crypto.Hash(0))
-	if err != nil {
-		return nil, fmt.Errorf("Sign: %v", err)
-	}
-
-	sigident := types.SigIdent{
-		KeyHash:   types.Hash(signer.Public().(ed25519.PublicKey)[:]),
-		Signature: &[types.SignatureSize]byte{},
+	sm.cosignature = map[[types.HashSize]byte]*types.SigIdent{
+		*next.SigIdent[0].KeyHash: next.SigIdent[0], // log signature
 	}
-	copy(sigident.Signature[:], sig)
-	return &types.SignedTreeHead{
-		TreeHead: *th,
-		SigIdent: []*types.SigIdent{
-			&sigident,
-		},
-	}, nil
+	glog.V(3).Infof("rotated tree heads")
 }
diff --git a/state/state_manager_test.go b/state/state_manager_test.go
index 6db8592..348074c 100644
--- a/state/state_manager_test.go
+++ b/state/state_manager_test.go
@@ -1,26 +1,393 @@
 package stfe
 
 import (
+	"bytes"
+	"context"
+	"crypto"
+	"crypto/ed25519"
+	"crypto/rand"
+	"fmt"
+	"reflect"
 	"testing"
+	"time"
+
+	"github.com/golang/mock/gomock"
+	"github.com/system-transparency/stfe/mocks"
+	"github.com/system-transparency/stfe/types"
+)
+
+var (
+	testSig = &[types.SignatureSize]byte{}
+	testPub = &[types.VerificationKeySize]byte{}
+	testTH  = &types.TreeHead{
+		Timestamp: 0,
+		TreeSize:  0,
+		RootHash:  types.Hash(nil),
+	}
+	testSigIdent = &types.SigIdent{
+		Signature: testSig,
+		KeyHash:   types.Hash(testPub[:]),
+	}
+	testSTH = &types.SignedTreeHead{
+		TreeHead: *testTH,
+		SigIdent: []*types.SigIdent{testSigIdent},
+	}
+	testSignerOK  = &mocks.TestSigner{testPub, testSig, nil}
+	testSignerErr = &mocks.TestSigner{testPub, testSig, fmt.Errorf("something went wrong")}
 )
 
 func TestNewStateManagerSingle(t *testing.T) {
+	for _, table := range []struct {
+		description string
+		signer      crypto.Signer
+		rsp         *types.TreeHead
+		err         error
+		wantErr     bool
+		wantSth     *types.SignedTreeHead
+	}{
+		{
+			description: "invalid: backend failure",
+			signer:      testSignerOK,
+			err:         fmt.Errorf("something went wrong"),
+			wantErr:     true,
+		},
+		{
+			description: "valid",
+			signer:      testSignerOK,
+			rsp:         testTH,
+			wantSth:     testSTH,
+		},
+	} {
+		// Run deferred functions at the end of each iteration
+		func() {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			client := mocks.NewMockClient(ctrl)
+			client.EXPECT().GetTreeHead(gomock.Any()).Return(table.rsp, table.err)
+
+			sm, err := NewStateManagerSingle(client, table.signer, time.Duration(0), time.Duration(0))
+			if got, want := err != nil, table.wantErr; got != want {
+				t.Errorf("got error %v but wanted %v in test %q: %v", got, want, table.description, err)
+			}
+			if err != nil {
+				return
+			}
+			if got, want := &sm.cosigned, table.wantSth; !reflect.DeepEqual(got, want) {
+				t.Errorf("got cosigned tree head\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+			}
+			if got, want := &sm.tosign, table.wantSth; !reflect.DeepEqual(got, want) {
+				t.Errorf("got tosign tree head\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+			}
+			// we only have log signature on startup
+			if got, want := len(sm.cosignature), 1; got != want {
+				t.Errorf("got %d cosignatures but wanted %d in test %q", got, want, table.description)
+			}
+		}()
+	}
 }
 
 func TestLatest(t *testing.T) {
+	for _, table := range []struct {
+		description string
+		signer      crypto.Signer
+		rsp         *types.TreeHead
+		err         error
+		wantErr     bool
+		wantSth     *types.SignedTreeHead
+	}{
+		{
+			description: "invalid: backend failure",
+			signer:      testSignerOK,
+			err:         fmt.Errorf("something went wrong"),
+			wantErr:     true,
+		},
+		{
+			description: "invalid: signature failure",
+			rsp:         testTH,
+			signer:      testSignerErr,
+			wantErr:     true,
+		},
+		{
+			description: "valid",
+			signer:      testSignerOK,
+			rsp:         testTH,
+			wantSth:     testSTH,
+		},
+	} {
+		// Run deferred functions at the end of each iteration
+		func() {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			client := mocks.NewMockClient(ctrl)
+			client.EXPECT().GetTreeHead(gomock.Any()).Return(table.rsp, table.err)
+			sm := StateManagerSingle{
+				client: client,
+				signer: table.signer,
+			}
+
+			sth, err := sm.Latest(context.Background())
+			if got, want := err != nil, table.wantErr; got != want {
+				t.Errorf("got error %v but wanted %v in test %q: %v", got, want, table.description, err)
+			}
+			if err != nil {
+				return
+			}
+			if got, want := sth, table.wantSth; !reflect.DeepEqual(got, want) {
+				t.Errorf("got signed tree head\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+			}
+		}()
+	}
 }
 
 func TestToSign(t *testing.T) {
+	description := "valid"
+	sm := StateManagerSingle{
+		tosign: *testSTH,
+	}
+	sth, err := sm.ToSign(context.Background())
+	if err != nil {
+		t.Errorf("ToSign should not fail with error: %v", err)
+		return
+	}
+	if got, want := sth, testSTH; !reflect.DeepEqual(got, want) {
+		t.Errorf("got signed tree head\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, description)
+	}
 }
 
 func TestCosigned(t *testing.T) {
+	description := "valid"
+	sm := StateManagerSingle{
+		cosigned: *testSTH,
+	}
+	sth, err := sm.Cosigned(context.Background())
+	if err != nil {
+		t.Errorf("Cosigned should not fail with error: %v", err)
+		return
+	}
+	if got, want := sth, testSTH; !reflect.DeepEqual(got, want) {
+		t.Errorf("got signed tree head\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, description)
+	}
 }
 
 func TestAddCosignature(t *testing.T) {
+	vk, sk, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		t.Fatalf("GenerateKey: %v", err)
+	}
+	if bytes.Equal(vk[:], testPub[:]) {
+		t.Fatalf("Sampled same key as testPub, aborting...")
+	}
+	var vkArray [types.VerificationKeySize]byte
+	copy(vkArray[:], vk[:])
+
+	for _, table := range []struct {
+		description string
+		signer      crypto.Signer
+		vk          *[types.VerificationKeySize]byte
+		th          *types.TreeHead
+		wantErr     bool
+	}{
+		{
+			description: "invalid: signature error",
+			signer:      sk,
+			vk:          testPub, // wrong key for message
+			th:          testTH,
+			wantErr:     true,
+		},
+		{
+			description: "valid",
+			signer:      sk,
+			vk:          &vkArray,
+			th:          testTH,
+		},
+	} {
+		sth, _ := table.th.Sign(testSignerOK)
+		logKeyHash := sth.SigIdent[0].KeyHash
+		logSigIdent := sth.SigIdent[0]
+		sm := &StateManagerSingle{
+			signer:   testSignerOK,
+			cosigned: *sth,
+			tosign:   *sth,
+			cosignature: map[[types.HashSize]byte]*types.SigIdent{
+				*logKeyHash: logSigIdent,
+			},
+		}
+
+		// Prepare witness signature
+		sth, err := table.th.Sign(table.signer)
+		if err != nil {
+			t.Fatalf("Sign: %v", err)
+		}
+		witnessKeyHash := sth.SigIdent[0].KeyHash
+		witnessSigIdent := sth.SigIdent[0]
+
+		// Add witness signature
+		err = sm.AddCosignature(context.Background(), table.vk, witnessSigIdent.Signature)
+		if got, want := err != nil, table.wantErr; got != want {
+			t.Errorf("got error %v but wanted %v in test %q: %v", got, want, table.description, err)
+		}
+		if err != nil {
+			continue
+		}
+
+		// We should have two signatures (log + witness)
+		if got, want := len(sm.cosignature), 2; got != want {
+			t.Errorf("got %d cosignatures but wanted %v in test %q", got, want, table.description)
+			continue
+		}
+		// check that log signature is there
+		sigident, ok := sm.cosignature[*logKeyHash]
+		if !ok {
+			t.Errorf("log signature is missing")
+			continue
+		}
+		if got, want := sigident, logSigIdent; !reflect.DeepEqual(got, want) {
+			t.Errorf("got log sigident\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+		}
+		// check that witness signature is there
+		sigident, ok = sm.cosignature[*witnessKeyHash]
+		if !ok {
+			t.Errorf("witness signature is missing")
+			continue
+		}
+		if got, want := sigident, witnessSigIdent; !reflect.DeepEqual(got, want) {
+			t.Errorf("got witness sigident\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+			continue
+		}
+
+		// Adding a duplicate signature should give an error
+		if err := sm.AddCosignature(context.Background(), table.vk, witnessSigIdent.Signature); err == nil {
+			t.Errorf("duplicate witness signature accepted as valid")
+		}
+	}
 }
 
 func TestRotate(t *testing.T) {
+	log := testSigIdent
+	wit1 := &types.SigIdent{
+		Signature: testSig,
+		KeyHash:   types.Hash([]byte("wit1 key")),
+	}
+	wit2 := &types.SigIdent{
+		Signature: testSig,
+		KeyHash:   types.Hash([]byte("wit2 key")),
+	}
+	th0 := testTH
+	th1 := &types.TreeHead{
+		Timestamp: 1,
+		TreeSize:  1,
+		RootHash:  types.Hash([]byte("1")),
+	}
+	th2 := &types.TreeHead{
+		Timestamp: 2,
+		TreeSize:  2,
+		RootHash:  types.Hash([]byte("2")),
+	}
+
+	for _, table := range []struct {
+		description   string
+		before, after *StateManagerSingle
+		next          *types.SignedTreeHead
+	}{
+		{
+			description: "tosign tree head repated, but got one new witnes signature",
+			before: &StateManagerSingle{
+				cosigned: types.SignedTreeHead{
+					TreeHead: *th0,
+					SigIdent: []*types.SigIdent{log, wit1},
+				},
+				tosign: types.SignedTreeHead{
+					TreeHead: *th0,
+					SigIdent: []*types.SigIdent{log},
+				},
+				cosignature: map[[types.HashSize]byte]*types.SigIdent{
+					*log.KeyHash:  log,
+					*wit2.KeyHash: wit2, // the new witness signature
+				},
+			},
+			next: &types.SignedTreeHead{
+				TreeHead: *th1,
+				SigIdent: []*types.SigIdent{log},
+			},
+			after: &StateManagerSingle{
+				cosigned: types.SignedTreeHead{
+					TreeHead: *th0,
+					SigIdent: []*types.SigIdent{log, wit1, wit2},
+				},
+				tosign: types.SignedTreeHead{
+					TreeHead: *th1,
+					SigIdent: []*types.SigIdent{log},
+				},
+				cosignature: map[[types.HashSize]byte]*types.SigIdent{
+					*log.KeyHash: log, // after rotate we always have log sig
+				},
+			},
+		},
+		{
+			description: "tosign tree head did not repeat, it got one witness signature",
+			before: &StateManagerSingle{
+				cosigned: types.SignedTreeHead{
+					TreeHead: *th0,
+					SigIdent: []*types.SigIdent{log, wit1},
+				},
+				tosign: types.SignedTreeHead{
+					TreeHead: *th1,
+					SigIdent: []*types.SigIdent{log},
+				},
+				cosignature: map[[types.HashSize]byte]*types.SigIdent{
+					*log.KeyHash:  log,
+					*wit2.KeyHash: wit2, // the only witness that signed tosign
+				},
+			},
+			next: &types.SignedTreeHead{
+				TreeHead: *th2,
+				SigIdent: []*types.SigIdent{log},
+			},
+			after: &StateManagerSingle{
+				cosigned: types.SignedTreeHead{
+					TreeHead: *th1,
+					SigIdent: []*types.SigIdent{log, wit2},
+				},
+				tosign: types.SignedTreeHead{
+					TreeHead: *th2,
+					SigIdent: []*types.SigIdent{log},
+				},
+				cosignature: map[[types.HashSize]byte]*types.SigIdent{
+					*log.KeyHash: log, // after rotate we always have log sig
+				},
+			},
+		},
+	} {
+		table.before.rotate(table.next)
+		if got, want := table.before.cosigned.TreeHead, table.after.cosigned.TreeHead; !reflect.DeepEqual(got, want) {
+			t.Errorf("got cosigned tree head\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+		}
+		checkWitnessList(t, table.description, table.before.cosigned.SigIdent, table.after.cosigned.SigIdent)
+		if got, want := table.before.tosign.TreeHead, table.after.tosign.TreeHead; !reflect.DeepEqual(got, want) {
+			t.Errorf("got tosign tree head\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+		}
+		checkWitnessList(t, table.description, table.before.tosign.SigIdent, table.after.tosign.SigIdent)
+		if got, want := table.before.cosignature, table.after.cosignature; !reflect.DeepEqual(got, want) {
+			t.Errorf("got cosignature map\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+		}
+	}
 }
 
-func TestSign(t *testing.T) {
+func checkWitnessList(t *testing.T, description string, got, want []*types.SigIdent) {
+	t.Helper()
+	for _, si := range got {
+		found := false
+		for _, sj := range want {
+			if reflect.DeepEqual(si, sj) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Errorf("got unexpected signature-signer pair with key hash in test %q: %x", description, si.KeyHash[:])
+		}
+	}
+	if len(got) != len(want) {
+		t.Errorf("got %d signature-signer pairs but wanted %d in test %q", len(got), len(want), description)
+	}
 }