From 0e00cf4ebb3393f9bcc680ecad1c3cea8a961382 Mon Sep 17 00:00:00 2001
From: mcrakhman <rakhmanov.m@gmail.com>
Date: Mon, 24 Apr 2023 20:33:35 +0200
Subject: [PATCH] Add receipt check

---
 commonspace/checks.go                    | 44 ++++++++++++
 coordinator/coordinatorclient/receipt.go | 85 ++++++++++++++++++++++++
 2 files changed, 129 insertions(+)
 create mode 100644 commonspace/checks.go
 create mode 100644 coordinator/coordinatorclient/receipt.go

diff --git a/commonspace/checks.go b/commonspace/checks.go
new file mode 100644
index 00000000..5469e2f2
--- /dev/null
+++ b/commonspace/checks.go
@@ -0,0 +1,44 @@
+package commonspace
+
+import (
+	"context"
+	"github.com/anytypeio/any-sync/commonspace/spacesyncproto"
+	"github.com/anytypeio/any-sync/net/peer"
+	"github.com/anytypeio/any-sync/nodeconf"
+	"github.com/anytypeio/any-sync/util/crypto"
+	"golang.org/x/exp/slices"
+)
+
+func CheckResponsible(ctx context.Context, confService nodeconf.Service, spaceId string) (err error) {
+	peerId, err := peer.CtxPeerId(ctx)
+	if err != nil {
+		return
+	}
+	if isClient(confService, peerId) && !confService.IsResponsible(spaceId) {
+		return spacesyncproto.ErrPeerIsNotResponsible
+	}
+	return
+}
+
+func isClient(confService nodeconf.Service, peerId string) bool {
+	return len(confService.NodeTypes(peerId)) == 0
+}
+
+func checkCoordinator(confService nodeconf.Service, identity []byte, payload, signature []byte) (err error) {
+	controlKey, err := crypto.UnmarshalEd25519PublicKey(identity)
+	if err != nil {
+		return
+	}
+	nodeTypes := confService.NodeTypes(controlKey.PeerId())
+	if len(nodeTypes) == 0 || !slices.Contains(nodeTypes, nodeconf.NodeTypeCoordinator) {
+		return errNoSuchCoordinatorNode
+	}
+	res, err := controlKey.Verify(payload, signature)
+	if err != nil {
+		return
+	}
+	if !res {
+		return errReceiptSignatureIncorrect
+	}
+	return
+}
diff --git a/coordinator/coordinatorclient/receipt.go b/coordinator/coordinatorclient/receipt.go
new file mode 100644
index 00000000..4a7f3162
--- /dev/null
+++ b/coordinator/coordinatorclient/receipt.go
@@ -0,0 +1,85 @@
+package coordinatorclient
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"github.com/anytypeio/any-sync/commonspace/spacesyncproto"
+	"github.com/anytypeio/any-sync/coordinator/coordinatorproto"
+	"github.com/anytypeio/any-sync/net/peer"
+	"github.com/anytypeio/any-sync/nodeconf"
+	"github.com/anytypeio/any-sync/util/crypto"
+	"github.com/gogo/protobuf/proto"
+	"golang.org/x/exp/slices"
+	"time"
+)
+
+var (
+	errReceiptSignatureIncorrect = errors.New("receipt signature is incorrect")
+	errNoSuchCoordinatorNode     = errors.New("no such control node")
+	errReceiptSpaceIdIncorrect   = errors.New("receipt space id is incorrect")
+	errReceiptPeerIdIncorrect    = errors.New("receipt peer id is incorrect")
+	errReceiptAccountIncorrect   = errors.New("receipt account id is incorrect")
+	errReceiptExpired            = errors.New("receipt is expired")
+)
+
+func CheckReceipt(ctx context.Context, confService nodeconf.Service, request *spacesyncproto.SpacePushRequest) (err error) {
+	peerId, err := peer.CtxPeerId(ctx)
+	if err != nil {
+		return
+	}
+	accountIdentity, err := peer.CtxIdentity(ctx)
+	if err != nil {
+		return
+	}
+	credential := &coordinatorproto.SpaceReceiptWithSignature{}
+	err = proto.Unmarshal(request.GetCredential(), credential)
+	if err != nil {
+		return
+	}
+	payload := &coordinatorproto.SpaceReceipt{}
+	err = proto.Unmarshal(credential.GetSpaceReceiptPayload(), payload)
+	if err != nil {
+		return
+	}
+	if payload.GetSpaceId() != request.GetPayload().GetSpaceHeader().GetId() {
+		return errReceiptSpaceIdIncorrect
+	}
+	if payload.GetPeerId() != peerId {
+		return errReceiptPeerIdIncorrect
+	}
+	if !bytes.Equal(payload.GetAccountIdentity(), accountIdentity) {
+		return errReceiptAccountIncorrect
+	}
+	err = checkCoordinator(
+		confService,
+		payload.GetControlNodeIdentity(),
+		credential.GetSpaceReceiptPayload(),
+		credential.GetSignature())
+	if err != nil {
+		return
+	}
+	if payload.GetValidUntil() < uint64(time.Now().Unix()) {
+		return errReceiptExpired
+	}
+	return
+}
+
+func checkCoordinator(confService nodeconf.Service, identity []byte, payload, signature []byte) (err error) {
+	cooordinatorKey, err := crypto.UnmarshalEd25519PublicKey(identity)
+	if err != nil {
+		return
+	}
+	nodeTypes := confService.NodeTypes(cooordinatorKey.PeerId())
+	if len(nodeTypes) == 0 || !slices.Contains(nodeTypes, nodeconf.NodeTypeCoordinator) {
+		return errNoSuchCoordinatorNode
+	}
+	res, err := cooordinatorKey.Verify(payload, signature)
+	if err != nil {
+		return
+	}
+	if !res {
+		return errReceiptSignatureIncorrect
+	}
+	return
+}