checking hash info when syncing (#746)

* checking hash info when syncing Co-authored-by: Will <will@cypherpunk.email>
drand · Oct 1, 2020 · c23577f · c23577f
1 parent 5b9a55a
commit c23577f
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Showing 2 changed files with 24 additions and 7 deletions.
diff --git a/core/drand_control.go b/core/drand_control.go
@@ -804,8 +804,6 @@ func (d *Drand) StartFollowChain(req *drand.StartFollowRequest, stream drand.Con
 	}()
 
 	addr := net.RemoteAddress(stream.Context())
-	// TODO put that hash verification back
-	// hash := req.GetInfoHash()
 	peers := make([]net.Peer, 0, len(req.GetNodes()))
 	for _, addr := range req.GetNodes() {
 		// XXX add TLS disable later
@@ -817,10 +815,14 @@ func (d *Drand) StartFollowChain(req *drand.StartFollowRequest, stream drand.Con
 	}
 	d.log.Debug("start_follow_chain", "fetched chain info", "hash", fmt.Sprintf("%x", info.Hash()))
 
-	// TODO UNCOMMENT WHEN HASH INCONSISTENCY FIXED
-	// if !bytes.Equal(info.Hash(),hash) {
-	//  return errors.New("invalid chain info hash!")
-	// }
+	hashStr := req.GetInfoHash()
+	hash, err := hex.DecodeString(hashStr)
+	if err != nil {
+		return fmt.Errorf("invalid hash info hex: %v", err)
+	}
+	if !bytes.Equal(info.Hash(), hash) {
+		return errors.New("invalid chain info hash!")
+	}
 
 	store, err := d.createBoltStore()
 	if err != nil {

diff --git a/core/drand_test.go b/core/drand_test.go
@@ -479,7 +479,7 @@ func TestDrandFollowChain(tt *testing.T) {
 
 	dt.MoveToTime(group.GenesisTime)
 	// do a few periods
-	for i := 0; i < 10; i++ {
+	for i := 0; i < 6; i++ {
 		dt.MoveTime(group.Period)
 	}
 
@@ -499,6 +499,21 @@ func TestDrandFollowChain(tt *testing.T) {
 	addrToFollow := []string{rootID.Address()}
 	hash := fmt.Sprintf("%x", chain.NewChainInfo(group).Hash())
 	tls := true
+	// First try with an invalid hash info
+	ctx, cancel = context.WithCancel(context.Background())
+	_, errCh, _ := newClient.StartFollowChain(ctx, "deadbeef", addrToFollow, tls, 10000)
+	select {
+	case <-errCh:
+	case <-time.After(100 * time.Millisecond):
+		tt.Fatal("should have errored")
+	}
+	_, errCh, _ = newClient.StartFollowChain(ctx, "tutu", addrToFollow, tls, 10000)
+	select {
+	case <-errCh:
+	case <-time.After(100 * time.Millisecond):
+		tt.Fatal("should have errored")
+	}
+
 	fn := func(upTo, exp uint64) {
 		ctx, cancel = context.WithCancel(context.Background())
 		progress, errCh, err := newClient.StartFollowChain(ctx, hash, addrToFollow, tls, upTo)