started using the refactored packages in siglog server

3 files changed, 744 insertions, 0 deletions

diff --git a/pkg/trillian/client.go b/pkg/trillian/client.go
new file mode 100644
index 0000000..9523e56
--- /dev/null
+++ b/pkg/trillian/client.go
@@ -0,0 +1,178 @@
+package trillian
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/golang/glog"
+	"github.com/google/trillian"
+	ttypes "github.com/google/trillian/types"
+	"github.com/system-transparency/stfe/pkg/types"
+	"google.golang.org/grpc/codes"
+)
+
+type Client interface {
+	AddLeaf(context.Context, *types.LeafRequest) error
+	GetConsistencyProof(context.Context, *types.ConsistencyProofRequest) (*types.ConsistencyProof, error)
+	GetTreeHead(context.Context) (*types.TreeHead, error)
+	GetInclusionProof(context.Context, *types.InclusionProofRequest) (*types.InclusionProof, error)
+	GetLeaves(context.Context, *types.LeavesRequest) (*types.LeafList, error)
+}
+
+// TrillianClient is a wrapper around the Trillian gRPC client.
+type TrillianClient struct {
+	// TreeID is a Merkle tree identifier that Trillian uses
+	TreeID int64
+
+	// GRPC is a Trillian gRPC client
+	GRPC trillian.TrillianLogClient
+}
+
+func (c *TrillianClient) AddLeaf(ctx context.Context, req *types.LeafRequest) error {
+	leaf := types.Leaf{
+		Message: req.Message,
+		SigIdent: types.SigIdent{
+			Signature: req.Signature,
+			KeyHash:   types.Hash(req.VerificationKey[:]),
+		},
+	}
+	serialized := leaf.Marshal()
+
+	glog.V(3).Infof("queueing leaf request: %x", types.HashLeaf(serialized))
+	rsp, err := c.GRPC.QueueLeaf(ctx, &trillian.QueueLeafRequest{
+		LogId: c.TreeID,
+		Leaf: &trillian.LogLeaf{
+			LeafValue: serialized,
+		},
+	})
+	if err != nil {
+		return fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return fmt.Errorf("no response")
+	}
+	if rsp.QueuedLeaf == nil {
+		return fmt.Errorf("no queued leaf")
+	}
+	if codes.Code(rsp.QueuedLeaf.GetStatus().GetCode()) == codes.AlreadyExists {
+		return fmt.Errorf("leaf is already queued or included")
+	}
+	return nil
+}
+
+func (c *TrillianClient) GetTreeHead(ctx context.Context) (*types.TreeHead, error) {
+	rsp, err := c.GRPC.GetLatestSignedLogRoot(ctx, &trillian.GetLatestSignedLogRootRequest{
+		LogId: c.TreeID,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return nil, fmt.Errorf("no response")
+	}
+	if rsp.SignedLogRoot == nil {
+		return nil, fmt.Errorf("no signed log root")
+	}
+	if rsp.SignedLogRoot.LogRoot == nil {
+		return nil, fmt.Errorf("no log root")
+	}
+	var r ttypes.LogRootV1
+	if err := r.UnmarshalBinary(rsp.SignedLogRoot.LogRoot); err != nil {
+		return nil, fmt.Errorf("no log root: unmarshal failed: %v", err)
+	}
+	if len(r.RootHash) != types.HashSize {
+		return nil, fmt.Errorf("unexpected hash length: %d", len(r.RootHash))
+	}
+	return treeHeadFromLogRoot(&r), nil
+}
+
+func (c *TrillianClient) GetConsistencyProof(ctx context.Context, req *types.ConsistencyProofRequest) (*types.ConsistencyProof, error) {
+	rsp, err := c.GRPC.GetConsistencyProof(ctx, &trillian.GetConsistencyProofRequest{
+		LogId:          c.TreeID,
+		FirstTreeSize:  int64(req.OldSize),
+		SecondTreeSize: int64(req.NewSize),
+	})
+	if err != nil {
+		return nil, fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return nil, fmt.Errorf("no response")
+	}
+	if rsp.Proof == nil {
+		return nil, fmt.Errorf("no consistency proof")
+	}
+	if len(rsp.Proof.Hashes) == 0 {
+		return nil, fmt.Errorf("not a consistency proof: empty")
+	}
+	path, err := nodePathFromHashes(rsp.Proof.Hashes)
+	if err != nil {
+		return nil, fmt.Errorf("not a consistency proof: %v", err)
+	}
+	return &types.ConsistencyProof{
+		OldSize: req.OldSize,
+		NewSize: req.NewSize,
+		Path:    path,
+	}, nil
+}
+
+func (c *TrillianClient) GetInclusionProof(ctx context.Context, req *types.InclusionProofRequest) (*types.InclusionProof, error) {
+	rsp, err := c.GRPC.GetInclusionProofByHash(ctx, &trillian.GetInclusionProofByHashRequest{
+		LogId:           c.TreeID,
+		LeafHash:        req.LeafHash[:],
+		TreeSize:        int64(req.TreeSize),
+		OrderBySequence: true,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return nil, fmt.Errorf("no response")
+	}
+	if len(rsp.Proof) != 1 {
+		return nil, fmt.Errorf("bad proof count: %d", len(rsp.Proof))
+	}
+	proof := rsp.Proof[0]
+	if len(proof.Hashes) == 0 {
+		return nil, fmt.Errorf("not an inclusion proof: empty")
+	}
+	path, err := nodePathFromHashes(proof.Hashes)
+	if err != nil {
+		return nil, fmt.Errorf("not an inclusion proof: %v", err)
+	}
+	return &types.InclusionProof{
+		TreeSize:  req.TreeSize,
+		LeafIndex: uint64(proof.LeafIndex),
+		Path:      path,
+	}, nil
+}
+
+func (c *TrillianClient) GetLeaves(ctx context.Context, req *types.LeavesRequest) (*types.LeafList, error) {
+	rsp, err := c.GRPC.GetLeavesByRange(ctx, &trillian.GetLeavesByRangeRequest{
+		LogId:      c.TreeID,
+		StartIndex: int64(req.StartSize),
+		Count:      int64(req.EndSize-req.StartSize) + 1,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return nil, fmt.Errorf("no response")
+	}
+	if got, want := len(rsp.Leaves), int(req.EndSize-req.StartSize+1); got != want {
+		return nil, fmt.Errorf("unexpected number of leaves: %d", got)
+	}
+	var list types.LeafList
+	for i, leaf := range rsp.Leaves {
+		leafIndex := int64(req.StartSize + uint64(i))
+		if leafIndex != leaf.LeafIndex {
+			return nil, fmt.Errorf("unexpected leaf(%d): got index %d", leafIndex, leaf.LeafIndex)
+		}
+
+		var l types.Leaf
+		if err := l.Unmarshal(leaf.LeafValue); err != nil {
+			return nil, fmt.Errorf("unexpected leaf(%d): %v", leafIndex, err)
+		}
+		list = append(list[:], &l)
+	}
+	return &list, nil
+}
diff --git a/pkg/trillian/client_test.go b/pkg/trillian/client_test.go
new file mode 100644
index 0000000..6b3d881
--- /dev/null
+++ b/pkg/trillian/client_test.go
@@ -0,0 +1,533 @@
+package trillian
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/golang/mock/gomock"
+	"github.com/google/trillian"
+	ttypes "github.com/google/trillian/types"
+	"github.com/system-transparency/stfe/pkg/mocks"
+	"github.com/system-transparency/stfe/pkg/types"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+func TestAddLeaf(t *testing.T) {
+	req := &types.LeafRequest{
+		Message: types.Message{
+			ShardHint: 0,
+			Checksum:  &[types.HashSize]byte{},
+		},
+		Signature:       &[types.SignatureSize]byte{},
+		VerificationKey: &[types.VerificationKeySize]byte{},
+		DomainHint:      "example.com",
+	}
+	for _, table := range []struct {
+		description string
+		req         *types.LeafRequest
+		rsp         *trillian.QueueLeafResponse
+		err         error
+		wantErr     bool
+	}{
+		{
+			description: "invalid: backend failure",
+			req:         req,
+			err:         fmt.Errorf("something went wrong"),
+			wantErr:     true,
+		},
+		{
+			description: "invalid: no response",
+			req:         req,
+			wantErr:     true,
+		},
+		{
+			description: "invalid: no queued leaf",
+			req:         req,
+			rsp:         &trillian.QueueLeafResponse{},
+			wantErr:     true,
+		},
+		{
+			description: "invalid: leaf is already queued or included",
+			req:         req,
+			rsp: &trillian.QueueLeafResponse{
+				QueuedLeaf: &trillian.QueuedLogLeaf{
+					Leaf: &trillian.LogLeaf{
+						LeafValue: req.Message.Marshal(),
+					},
+					Status: status.New(codes.AlreadyExists, "duplicate").Proto(),
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "valid",
+			req:         req,
+			rsp: &trillian.QueueLeafResponse{
+				QueuedLeaf: &trillian.QueuedLogLeaf{
+					Leaf: &trillian.LogLeaf{
+						LeafValue: req.Message.Marshal(),
+					},
+					Status: status.New(codes.OK, "ok").Proto(),
+				},
+			},
+		},
+	} {
+		// Run deferred functions at the end of each iteration
+		func() {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			grpc := mocks.NewMockTrillianLogClient(ctrl)
+			grpc.EXPECT().QueueLeaf(gomock.Any(), gomock.Any()).Return(table.rsp, table.err)
+			client := TrillianClient{GRPC: grpc}
+
+			err := client.AddLeaf(context.Background(), table.req)
+			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)
+			}
+		}()
+	}
+}
+
+func TestGetTreeHead(t *testing.T) {
+	// valid root
+	root := &ttypes.LogRootV1{
+		TreeSize:       0,
+		RootHash:       make([]byte, types.HashSize),
+		TimestampNanos: 1622585623133599429,
+	}
+	buf, err := root.MarshalBinary()
+	if err != nil {
+		t.Fatalf("must marshal log root: %v", err)
+	}
+	// invalid root
+	root.RootHash = make([]byte, types.HashSize+1)
+	bufBadHash, err := root.MarshalBinary()
+	if err != nil {
+		t.Fatalf("must marshal log root: %v", err)
+	}
+
+	for _, table := range []struct {
+		description string
+		rsp         *trillian.GetLatestSignedLogRootResponse
+		err         error
+		wantErr     bool
+		wantTh      *types.TreeHead
+	}{
+		{
+			description: "invalid: backend failure",
+			err:         fmt.Errorf("something went wrong"),
+			wantErr:     true,
+		},
+		{
+			description: "invalid: no response",
+			wantErr:     true,
+		},
+		{
+			description: "invalid: no signed log root",
+			rsp:         &trillian.GetLatestSignedLogRootResponse{},
+			wantErr:     true,
+		},
+		{
+			description: "invalid: no log root",
+			rsp: &trillian.GetLatestSignedLogRootResponse{
+				SignedLogRoot: &trillian.SignedLogRoot{},
+			},
+			wantErr: true,
+		},
+		{
+			description: "invalid: no log root: unmarshal failed",
+			rsp: &trillian.GetLatestSignedLogRootResponse{
+				SignedLogRoot: &trillian.SignedLogRoot{
+					LogRoot: buf[1:],
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "invalid: unexpected hash length",
+			rsp: &trillian.GetLatestSignedLogRootResponse{
+				SignedLogRoot: &trillian.SignedLogRoot{
+					LogRoot: bufBadHash,
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "valid",
+			rsp: &trillian.GetLatestSignedLogRootResponse{
+				SignedLogRoot: &trillian.SignedLogRoot{
+					LogRoot: buf,
+				},
+			},
+			wantTh: &types.TreeHead{
+				Timestamp: 1622585623,
+				TreeSize:  0,
+				RootHash:  &[types.HashSize]byte{},
+			},
+		},
+	} {
+		// Run deferred functions at the end of each iteration
+		func() {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			grpc := mocks.NewMockTrillianLogClient(ctrl)
+			grpc.EXPECT().GetLatestSignedLogRoot(gomock.Any(), gomock.Any()).Return(table.rsp, table.err)
+			client := TrillianClient{GRPC: grpc}
+
+			th, err := client.GetTreeHead(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 := th, table.wantTh; !reflect.DeepEqual(got, want) {
+				t.Errorf("got tree head\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+			}
+		}()
+	}
+}
+
+func TestGetConsistencyProof(t *testing.T) {
+	req := &types.ConsistencyProofRequest{
+		OldSize: 1,
+		NewSize: 3,
+	}
+	for _, table := range []struct {
+		description string
+		req         *types.ConsistencyProofRequest
+		rsp         *trillian.GetConsistencyProofResponse
+		err         error
+		wantErr     bool
+		wantProof   *types.ConsistencyProof
+	}{
+		{
+			description: "invalid: backend failure",
+			req:         req,
+			err:         fmt.Errorf("something went wrong"),
+			wantErr:     true,
+		},
+		{
+			description: "invalid: no response",
+			req:         req,
+			wantErr:     true,
+		},
+		{
+			description: "invalid: no consistency proof",
+			req:         req,
+			rsp:         &trillian.GetConsistencyProofResponse{},
+			wantErr:     true,
+		},
+		{
+			description: "invalid: not a consistency proof (1/2)",
+			req:         req,
+			rsp: &trillian.GetConsistencyProofResponse{
+				Proof: &trillian.Proof{
+					Hashes: [][]byte{},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "invalid: not a consistency proof (2/2)",
+			req:         req,
+			rsp: &trillian.GetConsistencyProofResponse{
+				Proof: &trillian.Proof{
+					Hashes: [][]byte{
+						make([]byte, types.HashSize),
+						make([]byte, types.HashSize+1),
+					},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "valid",
+			req:         req,
+			rsp: &trillian.GetConsistencyProofResponse{
+				Proof: &trillian.Proof{
+					Hashes: [][]byte{
+						make([]byte, types.HashSize),
+						make([]byte, types.HashSize),
+					},
+				},
+			},
+			wantProof: &types.ConsistencyProof{
+				OldSize: 1,
+				NewSize: 3,
+				Path: []*[types.HashSize]byte{
+					&[types.HashSize]byte{},
+					&[types.HashSize]byte{},
+				},
+			},
+		},
+	} {
+		// Run deferred functions at the end of each iteration
+		func() {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			grpc := mocks.NewMockTrillianLogClient(ctrl)
+			grpc.EXPECT().GetConsistencyProof(gomock.Any(), gomock.Any()).Return(table.rsp, table.err)
+			client := TrillianClient{GRPC: grpc}
+
+			proof, err := client.GetConsistencyProof(context.Background(), table.req)
+			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 := proof, table.wantProof; !reflect.DeepEqual(got, want) {
+				t.Errorf("got proof\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+			}
+		}()
+	}
+}
+
+func TestGetInclusionProof(t *testing.T) {
+	req := &types.InclusionProofRequest{
+		TreeSize: 4,
+		LeafHash: &[types.HashSize]byte{},
+	}
+	for _, table := range []struct {
+		description string
+		req         *types.InclusionProofRequest
+		rsp         *trillian.GetInclusionProofByHashResponse
+		err         error
+		wantErr     bool
+		wantProof   *types.InclusionProof
+	}{
+		{
+			description: "invalid: backend failure",
+			req:         req,
+			err:         fmt.Errorf("something went wrong"),
+			wantErr:     true,
+		},
+		{
+			description: "invalid: no response",
+			req:         req,
+			wantErr:     true,
+		},
+		{
+			description: "invalid: bad proof count",
+			req:         req,
+			rsp: &trillian.GetInclusionProofByHashResponse{
+				Proof: []*trillian.Proof{
+					&trillian.Proof{},
+					&trillian.Proof{},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "invalid: not an inclusion proof (1/2)",
+			req:         req,
+			rsp: &trillian.GetInclusionProofByHashResponse{
+				Proof: []*trillian.Proof{
+					&trillian.Proof{
+						LeafIndex: 1,
+						Hashes:    [][]byte{},
+					},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "invalid: not an inclusion proof (2/2)",
+			req:         req,
+			rsp: &trillian.GetInclusionProofByHashResponse{
+				Proof: []*trillian.Proof{
+					&trillian.Proof{
+						LeafIndex: 1,
+						Hashes: [][]byte{
+							make([]byte, types.HashSize),
+							make([]byte, types.HashSize+1),
+						},
+					},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "valid",
+			req:         req,
+			rsp: &trillian.GetInclusionProofByHashResponse{
+				Proof: []*trillian.Proof{
+					&trillian.Proof{
+						LeafIndex: 1,
+						Hashes: [][]byte{
+							make([]byte, types.HashSize),
+							make([]byte, types.HashSize),
+						},
+					},
+				},
+			},
+			wantProof: &types.InclusionProof{
+				TreeSize:  4,
+				LeafIndex: 1,
+				Path: []*[types.HashSize]byte{
+					&[types.HashSize]byte{},
+					&[types.HashSize]byte{},
+				},
+			},
+		},
+	} {
+		// Run deferred functions at the end of each iteration
+		func() {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			grpc := mocks.NewMockTrillianLogClient(ctrl)
+			grpc.EXPECT().GetInclusionProofByHash(gomock.Any(), gomock.Any()).Return(table.rsp, table.err)
+			client := TrillianClient{GRPC: grpc}
+
+			proof, err := client.GetInclusionProof(context.Background(), table.req)
+			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 := proof, table.wantProof; !reflect.DeepEqual(got, want) {
+				t.Errorf("got proof\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+			}
+		}()
+	}
+}
+
+func TestGetLeaves(t *testing.T) {
+	req := &types.LeavesRequest{
+		StartSize: 1,
+		EndSize:   2,
+	}
+	firstLeaf := &types.Leaf{
+		Message: types.Message{
+			ShardHint: 0,
+			Checksum:  &[types.HashSize]byte{},
+		},
+		SigIdent: types.SigIdent{
+			Signature: &[types.SignatureSize]byte{},
+			KeyHash:   &[types.HashSize]byte{},
+		},
+	}
+	secondLeaf := &types.Leaf{
+		Message: types.Message{
+			ShardHint: 0,
+			Checksum:  &[types.HashSize]byte{},
+		},
+		SigIdent: types.SigIdent{
+			Signature: &[types.SignatureSize]byte{},
+			KeyHash:   &[types.HashSize]byte{},
+		},
+	}
+
+	for _, table := range []struct {
+		description string
+		req         *types.LeavesRequest
+		rsp         *trillian.GetLeavesByRangeResponse
+		err         error
+		wantErr     bool
+		wantLeaves  *types.LeafList
+	}{
+		{
+			description: "invalid: backend failure",
+			req:         req,
+			err:         fmt.Errorf("something went wrong"),
+			wantErr:     true,
+		},
+		{
+			description: "invalid: no response",
+			req:         req,
+			wantErr:     true,
+		},
+		{
+			description: "invalid: unexpected number of leaves",
+			req:         req,
+			rsp: &trillian.GetLeavesByRangeResponse{
+				Leaves: []*trillian.LogLeaf{
+					&trillian.LogLeaf{
+						LeafValue: firstLeaf.Marshal(),
+						LeafIndex: 1,
+					},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "invalid: unexpected leaf (1/2)",
+			req:         req,
+			rsp: &trillian.GetLeavesByRangeResponse{
+				Leaves: []*trillian.LogLeaf{
+					&trillian.LogLeaf{
+						LeafValue: firstLeaf.Marshal(),
+						LeafIndex: 1,
+					},
+					&trillian.LogLeaf{
+						LeafValue: secondLeaf.Marshal(),
+						LeafIndex: 3,
+					},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "invalid: unexpected leaf (2/2)",
+			req:         req,
+			rsp: &trillian.GetLeavesByRangeResponse{
+				Leaves: []*trillian.LogLeaf{
+					&trillian.LogLeaf{
+						LeafValue: firstLeaf.Marshal(),
+						LeafIndex: 1,
+					},
+					&trillian.LogLeaf{
+						LeafValue: secondLeaf.Marshal()[1:],
+						LeafIndex: 2,
+					},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			description: "valid",
+			req:         req,
+			rsp: &trillian.GetLeavesByRangeResponse{
+				Leaves: []*trillian.LogLeaf{
+					&trillian.LogLeaf{
+						LeafValue: firstLeaf.Marshal(),
+						LeafIndex: 1,
+					},
+					&trillian.LogLeaf{
+						LeafValue: secondLeaf.Marshal(),
+						LeafIndex: 2,
+					},
+				},
+			},
+			wantLeaves: &types.LeafList{
+				firstLeaf,
+				secondLeaf,
+			},
+		},
+	} {
+		// Run deferred functions at the end of each iteration
+		func() {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			grpc := mocks.NewMockTrillianLogClient(ctrl)
+			grpc.EXPECT().GetLeavesByRange(gomock.Any(), gomock.Any()).Return(table.rsp, table.err)
+			client := TrillianClient{GRPC: grpc}
+
+			leaves, err := client.GetLeaves(context.Background(), table.req)
+			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 := leaves, table.wantLeaves; !reflect.DeepEqual(got, want) {
+				t.Errorf("got leaves\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
+			}
+		}()
+	}
+}
diff --git a/pkg/trillian/util.go b/pkg/trillian/util.go
new file mode 100644
index 0000000..4cf31fb
--- /dev/null
+++ b/pkg/trillian/util.go
@@ -0,0 +1,33 @@
+package trillian
+
+import (
+	"fmt"
+
+	trillian "github.com/google/trillian/types"
+	siglog "github.com/system-transparency/stfe/pkg/types"
+)
+
+func treeHeadFromLogRoot(lr *trillian.LogRootV1) *siglog.TreeHead {
+	var hash [siglog.HashSize]byte
+	th := siglog.TreeHead{
+		Timestamp: uint64(lr.TimestampNanos / 1000 / 1000 / 1000),
+		TreeSize:  uint64(lr.TreeSize),
+		RootHash:  &hash,
+	}
+	copy(th.RootHash[:], lr.RootHash)
+	return &th
+}
+
+func nodePathFromHashes(hashes [][]byte) ([]*[siglog.HashSize]byte, error) {
+	var path []*[siglog.HashSize]byte
+	for _, hash := range hashes {
+		if len(hash) != siglog.HashSize {
+			return nil, fmt.Errorf("unexpected hash length: %v", len(hash))
+		}
+
+		var h [siglog.HashSize]byte
+		copy(h[:], hash)
+		path = append(path, &h)
+	}
+	return path, nil
+}