dkg: check disk writes (#676)

Check disk writes by creating random sample files and then removing sample ones if successful.

category: bug
ticket: #584

dkg/disk.go

@@ -16,7 +16,9 @@
 package dkg
 
 import (
+	"crypto/rand"
 	"encoding/json"
+	"fmt"
 	"os"
 	"path"
 
@@ -28,7 +30,9 @@ import (
 	"github.com/obolnetwork/charon/core"
 	"github.com/obolnetwork/charon/eth2util/deposit"
 	"github.com/obolnetwork/charon/eth2util/keystore"
+	"github.com/obolnetwork/charon/tbls"
 	"github.com/obolnetwork/charon/tbls/tblsconv"
+	"github.com/obolnetwork/charon/testutil"
 )
 
 // loadDefinition returns the cluster definition from disk (or the test definition if configured).
@@ -112,10 +116,74 @@ func writeDepositData(aggSigs map[core.PubKey]*bls_sig.Signature, withdrawalAddr
 
 	// Write it to disk
 	depositPath := path.Join(dataDir, "deposit-data.json")
-	err = os.WriteFile(depositPath, bytes, 0o400) // read-only
+	err = os.WriteFile(depositPath, bytes, 0o444) // read-only
 	if err != nil {
 		return errors.Wrap(err, "write deposit data")
 	}
 
 	return nil
 }
+
+// checkWrites writes sample files to check disk writes and removes sample files after verification.
+func checkWrites(dataDir string, def cluster.Definition) error {
+	var shares []share
+	sigs := make(map[core.PubKey]*bls_sig.Signature)
+	for i := 0; i < def.NumValidators; i++ {
+		tss, sks, err := tbls.GenerateTSS(def.Threshold, len(def.Operators), rand.Reader)
+		if err != nil {
+			return err
+		}
+
+		shares = append(shares, share{
+			PubKey:       tss.PublicKey(),
+			SecretShare:  sks[0],
+			PublicShares: tss.PublicShares(),
+		})
+
+		pk, err := tblsconv.KeyToCore(tss.PublicKey())
+		if err != nil {
+			return err
+		}
+
+		sig, err := testutil.RandomBLSSignature()
+		if err != nil {
+			return err
+		}
+
+		sigs[pk] = sig
+	}
+
+	if err := writeDepositData(sigs, testutil.RandomETHAddress(), "prater", dataDir); err != nil {
+		return err
+	}
+
+	if err := writeKeystores(dataDir, shares); err != nil {
+		return err
+	}
+
+	lock := cluster.Lock{Definition: def}
+	if err := writeLock(dataDir, lock); err != nil {
+		return err
+	}
+
+	// Cleanup sample files
+	if err := os.Remove(path.Join(dataDir, "deposit-data.json")); err != nil {
+		return errors.Wrap(err, "remove sample deposit-data.json")
+	}
+
+	for i := 0; i < def.NumValidators; i++ {
+		if err := os.Remove(path.Join(dataDir, fmt.Sprintf("keystore-%d.json", i))); err != nil {
+			return errors.Wrap(err, fmt.Sprintf("remove sample keystore-%d.json", i))
+		}
+
+		if err := os.Remove(path.Join(dataDir, fmt.Sprintf("keystore-%d.txt", i))); err != nil {
+			return errors.Wrap(err, fmt.Sprintf("remove sample keystore-%d.txt", i))
+		}
+	}
+
+	if err := os.Remove(path.Join(dataDir, "cluster-lock.json")); err != nil {
+		return errors.Wrap(err, "remove sample cluster-lock.json")
+	}
+
+	return nil
+}

dkg/dkg.go

@@ -69,6 +69,10 @@ func Run(ctx context.Context, conf Config) (err error) {
 		return err
 	}
 
+	if err = checkWrites(conf.DataDir, def); err != nil {
+		return err
+	}
+
 	network, err := forkVersionToNetwork(def.ForkVersion)
 	if err != nil {
 		return err

eth2util/keystore/keystore.go

@@ -56,7 +56,7 @@ func StoreKeys(secrets []*bls_sig.SecretKey, dir string) error {
 		}
 
 		filename := path.Join(dir, fmt.Sprintf("keystore-%d.json", i))
-		if err := os.WriteFile(filename, b, 0o400); err != nil {
+		if err := os.WriteFile(filename, b, 0o444); err != nil {
 			return errors.Wrap(err, "write keystore")
 		}
 

testutil/random.go

@@ -30,6 +30,8 @@ import (
 	"github.com/attestantio/go-eth2-client/spec/altair"
 	"github.com/attestantio/go-eth2-client/spec/bellatrix"
 	eth2p0 "github.com/attestantio/go-eth2-client/spec/phase0"
+	"github.com/coinbase/kryptology/pkg/core/curves/native/bls12381"
+	"github.com/coinbase/kryptology/pkg/signatures/bls/bls_sig"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/enr"
@@ -40,6 +42,7 @@ import (
 	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/stretchr/testify/require"
 
+	"github.com/obolnetwork/charon/app/errors"
 	"github.com/obolnetwork/charon/core"
 	"github.com/obolnetwork/charon/tbls"
 	"github.com/obolnetwork/charon/tbls/tblsconv"
@@ -239,6 +242,15 @@ func RandomRoot() eth2p0.Root {
 	return resp
 }
 
+func RandomBLSSignature() (*bls_sig.Signature, error) {
+	g2, err := new(bls12381.G2).Random(crand.Reader)
+	if err != nil {
+		return nil, errors.Wrap(err, "random point in g2")
+	}
+
+	return &bls_sig.Signature{Value: *g2}, nil
+}
+
 func RandomEth2Signature() eth2p0.BLSSignature {
 	var resp eth2p0.BLSSignature
 	_, _ = rand.Read(resp[:])