QSP-6: Enforces crypto-secure PRNGs (#6401)

* adds cryptorand analyzer

* better naming

* rely on suffix

* sync/pending_* use crypto/rand

* define shared/rand

* updates fetcher

* fixes rand issue in sync package

* gofmt

* shared/rand: more docs + add exclusion nogo_config.json

* updates validator/assignments

* updates comment

* fixes remaning cases

* re-arranges comments

* fixes tests

* renames in shared/rand API

* adds simple no-panic test

* gazelle

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

BUILD.bazel

@@ -105,6 +105,7 @@ nogo(
         "@org_golang_x_tools//go/analysis/passes/asmdecl:go_tool_library",
         "//tools/analyzers/maligned:go_tool_library",
         "//tools/analyzers/roughtime:go_tool_library",
+        "//tools/analyzers/cryptorand:go_tool_library",
         "//tools/analyzers/errcheck:go_tool_library",
         "//tools/analyzers/featureconfig:go_tool_library",
     ] + select({

beacon-chain/db/testing/BUILD.bazel

@@ -10,6 +10,7 @@ go_library(
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/db:go_default_library",
         "//beacon-chain/db/kv:go_default_library",
+        "//shared/rand:go_default_library",
         "//shared/testutil:go_default_library",
     ],
 )

beacon-chain/db/testing/setup_db.go

@@ -3,25 +3,21 @@
 package testing
 
 import (
-	"crypto/rand"
 	"fmt"
-	"math/big"
 	"os"
 	"path"
 	"testing"
 
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db/kv"
+	"github.com/prysmaticlabs/prysm/shared/rand"
 	"github.com/prysmaticlabs/prysm/shared/testutil"
 )
 
 // SetupDB instantiates and returns database backed by key value store.
 func SetupDB(t testing.TB) (db.Database, *cache.StateSummaryCache) {
-	randPath, err := rand.Int(rand.Reader, big.NewInt(1000000))
-	if err != nil {
-		t.Fatalf("could not generate random file path: %v", err)
-	}
+	randPath := rand.NewDeterministicGenerator().Int()
 	p := path.Join(testutil.TempDir(), fmt.Sprintf("/%d", randPath))
 	if err := os.RemoveAll(p); err != nil {
 		t.Fatalf("failed to remove directory: %v", err)

beacon-chain/rpc/service.go

@@ -5,9 +5,7 @@ package rpc
 import (
 	"context"
 	"fmt"
-	"math/rand"
 	"net"
-	"os"
 
 	middleware "github.com/grpc-ecosystem/go-grpc-middleware"
 	recovery "github.com/grpc-ecosystem/go-grpc-middleware/recovery"
@@ -50,7 +48,6 @@ var log logrus.FieldLogger
 
 func init() {
 	log = logrus.WithField("prefix", "rpc")
-	rand.Seed(int64(os.Getpid()))
 }
 
 // Service defining an RPC server for a beacon node.

beacon-chain/rpc/validator/BUILD.bazel

@@ -43,6 +43,7 @@ go_library(
         "//shared/featureconfig:go_default_library",
         "//shared/hashutil:go_default_library",
         "//shared/params:go_default_library",
+        "//shared/rand:go_default_library",
         "//shared/roughtime:go_default_library",
         "//shared/slotutil:go_default_library",
         "//shared/traceutil:go_default_library",

beacon-chain/rpc/validator/assignments.go

@@ -2,11 +2,8 @@ package validator
 
 import (
 	"context"
-	"crypto/rand"
-	"math/big"
 	"time"
 
-	"github.com/pkg/errors"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
@@ -15,6 +12,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/rand"
 	"github.com/prysmaticlabs/prysm/shared/roughtime"
 	"github.com/prysmaticlabs/prysm/shared/slotutil"
 	"google.golang.org/grpc/codes"
@@ -178,12 +176,8 @@ func (vs *Server) duties(ctx context.Context, req *ethpb.DutiesRequest) (*ethpb.
 		validatorAssignments = append(validatorAssignments, assignment)
 		nextValidatorAssignments = append(nextValidatorAssignments, nextAssignment)
 		// Assign relevant validator to subnet.
-		if err := assignValidatorToSubnet(pubKey, assignment.Status); err != nil {
-			return nil, errors.Wrap(err, "could not assign validator to subnet")
-		}
-		if err := assignValidatorToSubnet(pubKey, nextAssignment.Status); err != nil {
-			return nil, errors.Wrap(err, "could not assign validator to subnet")
-		}
+		assignValidatorToSubnet(pubKey, assignment.Status)
+		assignValidatorToSubnet(pubKey, nextAssignment.Status)
 	}
 
 	return &ethpb.DutiesResponse{
@@ -195,33 +189,26 @@ func (vs *Server) duties(ctx context.Context, req *ethpb.DutiesRequest) (*ethpb.
 
 // assignValidatorToSubnet checks the status and pubkey of a particular validator
 // to discern whether persistent subnets need to be registered for them.
-func assignValidatorToSubnet(pubkey []byte, status ethpb.ValidatorStatus) error {
+func assignValidatorToSubnet(pubkey []byte, status ethpb.ValidatorStatus) {
 	if status != ethpb.ValidatorStatus_ACTIVE && status != ethpb.ValidatorStatus_EXITING {
-		return nil
+		return
 	}
 
 	_, ok, expTime := cache.SubnetIDs.GetPersistentSubnets(pubkey)
 	if ok && expTime.After(roughtime.Now()) {
-		return nil
+		return
 	}
 	epochDuration := time.Duration(params.BeaconConfig().SlotsPerEpoch * params.BeaconConfig().SecondsPerSlot)
 	assignedIdxs := []uint64{}
+	randGen := rand.NewGenerator()
 	for i := uint64(0); i < params.BeaconNetworkConfig().RandomSubnetsPerValidator; i++ {
-		randInt, err := rand.Int(rand.Reader, big.NewInt(int64(params.BeaconNetworkConfig().AttestationSubnetCount)))
-		if err != nil {
-			return errors.Wrap(err, "could not get random subnet index")
-		}
-		assignedIdxs = append(assignedIdxs, randInt.Uint64())
+		assignedIdx := randGen.Intn(int(params.BeaconNetworkConfig().AttestationSubnetCount))
+		assignedIdxs = append(assignedIdxs, uint64(assignedIdx))
 	}
 
-	randInt, err := rand.Int(rand.Reader, big.NewInt(int64(params.BeaconNetworkConfig().EpochsPerRandomSubnetSubscription)))
-	if err != nil {
-		return errors.Wrap(err, "could not get random subnet duration")
-	}
-	assignedDuration := randInt.Int64()
-	assignedDuration += int64(params.BeaconNetworkConfig().EpochsPerRandomSubnetSubscription)
+	assignedDuration := randGen.Intn(int(params.BeaconNetworkConfig().EpochsPerRandomSubnetSubscription))
+	assignedDuration += int(params.BeaconNetworkConfig().EpochsPerRandomSubnetSubscription)
 
 	totalDuration := epochDuration * time.Duration(assignedDuration)
 	cache.SubnetIDs.AddPersistentCommittee(pubkey, assignedIdxs, totalDuration*time.Second)
-	return nil
 }

beacon-chain/rpc/validator/assignments_test.go

@@ -467,9 +467,7 @@ func TestStreamDuties_OK_ChainReorg(t *testing.T) {
 func TestAssignValidatorToSubnet(t *testing.T) {
 	k := pubKey(3)
 
-	if err := assignValidatorToSubnet(k, ethpb.ValidatorStatus_ACTIVE); err != nil {
-		t.Fatal(err)
-	}
+	assignValidatorToSubnet(k, ethpb.ValidatorStatus_ACTIVE)
 	coms, ok, exp := cache.SubnetIDs.GetPersistentSubnets(k)
 	if !ok {
 		t.Fatal("No cache entry found for validator")

beacon-chain/rpc/validator/proposer.go

@@ -2,7 +2,6 @@ package validator
 
 import (
 	"context"
-	"crypto/rand"
 	"fmt"
 	"math/big"
 	"time"
@@ -23,6 +22,7 @@ import (
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/rand"
 	"github.com/prysmaticlabs/prysm/shared/trieutil"
 	"go.opencensus.io/trace"
 	"google.golang.org/grpc/codes"
@@ -223,18 +223,9 @@ func (vs *Server) randomETH1DataVote(ctx context.Context) (*ethpb.Eth1Data, erro
 	}
 	// set random roots and block hashes to prevent a majority from being
 	// built if the eth1 node is offline
-	randomDepBytes := make([]byte, 32)
-	randomBlkBytes := make([]byte, 32)
-	_, err = rand.Read(randomDepBytes)
-	if err != nil {
-		return nil, err
-	}
-	_, err = rand.Read(randomBlkBytes)
-	if err != nil {
-		return nil, err
-	}
-	depRoot := hashutil.Hash(randomDepBytes)
-	blockHash := hashutil.Hash(randomBlkBytes)
+	randGen := rand.NewGenerator()
+	depRoot := hashutil.Hash(bytesutil.Bytes32(randGen.Uint64()))
+	blockHash := hashutil.Hash(bytesutil.Bytes32(randGen.Uint64()))
 	return &ethpb.Eth1Data{
 		DepositRoot:  depRoot[:],
 		DepositCount: headState.Eth1DepositIndex(),

beacon-chain/sync/BUILD.bazel

@@ -71,6 +71,7 @@ go_library(
         "//shared/messagehandler:go_default_library",
         "//shared/p2putils:go_default_library",
         "//shared/params:go_default_library",
+        "//shared/rand:go_default_library",
         "//shared/roughtime:go_default_library",
         "//shared/runutil:go_default_library",
         "//shared/sliceutil:go_default_library",
@@ -89,7 +90,6 @@ go_library(
         "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@io_opencensus_go//trace:go_default_library",
-        "@org_golang_x_exp//rand:go_default_library",
     ],
 )
 

beacon-chain/sync/initial-sync/BUILD.bazel

@@ -30,6 +30,7 @@ go_library(
         "//shared/bytesutil:go_default_library",
         "//shared/mathutil:go_default_library",
         "//shared/params:go_default_library",
+        "//shared/rand:go_default_library",
         "//shared/roughtime:go_default_library",
         "@com_github_kevinms_leakybucket_go//:go_default_library",
         "@com_github_libp2p_go_libp2p_core//peer:go_default_library",

beacon-chain/sync/initial-sync/blocks_fetcher.go

@@ -2,12 +2,9 @@ package initialsync
 
 import (
 	"context"
-	"crypto/rand"
 	"fmt"
 	"io"
 	"math"
-	"math/big"
-	mathRand "math/rand"
 	"sort"
 	"sync"
 	"time"
@@ -24,6 +21,7 @@ import (
 	p2ppb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/mathutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/rand"
 	"github.com/prysmaticlabs/prysm/shared/roughtime"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
@@ -64,6 +62,7 @@ type blocksFetcher struct {
 	sync.Mutex
 	ctx             context.Context
 	cancel          context.CancelFunc
+	rand            *rand.Rand
 	headFetcher     blockchain.HeadFetcher
 	p2p             p2p.P2P
 	blocksPerSecond uint64
@@ -108,6 +107,7 @@ func newBlocksFetcher(ctx context.Context, cfg *blocksFetcherConfig) *blocksFetc
 	return &blocksFetcher{
 		ctx:             ctx,
 		cancel:          cancel,
+		rand:            rand.NewGenerator(),
 		headFetcher:     cfg.headFetcher,
 		p2p:             cfg.p2p,
 		blocksPerSecond: uint64(blocksPerSecond),
@@ -387,11 +387,7 @@ func (f *blocksFetcher) selectFailOverPeer(excludedPID peer.ID, peers []peer.ID)
 		return "", errNoPeersAvailable
 	}
 
-	randInt, err := rand.Int(rand.Reader, big.NewInt(int64(len(peers))))
-	if err != nil {
-		return "", err
-	}
-	return peers[randInt.Int64()], nil
+	return peers[f.rand.Int()%len(peers)], nil
 }
 
 // waitForMinimumPeers spins and waits up until enough peers are available.
@@ -425,12 +421,7 @@ func (f *blocksFetcher) filterPeers(peers []peer.ID, peersPercentage float64) ([
 
 	// Shuffle peers to prevent a bad peer from
 	// stalling sync with invalid blocks.
-	randSource, err := rand.Int(rand.Reader, big.NewInt(roughtime.Now().Unix()))
-	if err != nil {
-		return nil, errors.Wrap(err, "could not generate random int")
-	}
-	randGenerator := mathRand.New(mathRand.NewSource(randSource.Int64()))
-	randGenerator.Shuffle(len(peers), func(i, j int) {
+	f.rand.Shuffle(len(peers), func(i, j int) {
 		peers[i], peers[j] = peers[j], peers[i]
 	})
 
@@ -478,11 +469,6 @@ func (f *blocksFetcher) nonSkippedSlotAfter(ctx context.Context, slot uint64) (u
 		return 0, errNoPeersAvailable
 	}
 
-	randSource, err := rand.Int(rand.Reader, big.NewInt(roughtime.Now().Unix()))
-	if err != nil {
-		return 0, errors.Wrap(err, "could not generate random int")
-	}
-	randGenerator := mathRand.New(mathRand.NewSource(randSource.Int64()))
 	slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
 	pidInd := 0
 
@@ -525,7 +511,7 @@ func (f *blocksFetcher) nonSkippedSlotAfter(ctx context.Context, slot uint64) (u
 	slot = slot + nonSkippedSlotsFullSearchEpochs*slotsPerEpoch
 	upperBoundSlot := helpers.StartSlot(epoch + 1)
 	for ind := slot + 1; ind < upperBoundSlot; ind += (slotsPerEpoch * slotsPerEpoch) / 2 {
-		start := ind + uint64(randGenerator.Intn(int(slotsPerEpoch)))
+		start := ind + uint64(f.rand.Intn(int(slotsPerEpoch)))
 		nextSlot, err := fetch(peers[pidInd%len(peers)], start, slotsPerEpoch/2, slotsPerEpoch)
 		if err != nil {
 			return 0, err

beacon-chain/sync/pending_attestations_queue.go

@@ -13,12 +13,12 @@ import (
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/rand"
 	"github.com/prysmaticlabs/prysm/shared/runutil"
 	"github.com/prysmaticlabs/prysm/shared/slotutil"
 	"github.com/prysmaticlabs/prysm/shared/traceutil"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
-	"golang.org/x/exp/rand"
 )
 
 // This defines how often a node cleans up and processes pending attestations in the queue.
@@ -60,6 +60,7 @@ func (s *Service) processPendingAtts(ctx context.Context) error {
 	}
 	s.pendingAttsLock.RUnlock()
 
+	randGen := rand.NewGenerator()
 	for _, bRoot := range roots {
 		s.pendingAttsLock.RLock()
 		attestations := s.blkRootToPendingAtts[bRoot]
@@ -130,7 +131,7 @@ func (s *Service) processPendingAtts(ctx context.Context) error {
 				log.Debug("No peer IDs available to request missing block from for pending attestation")
 				return nil
 			}
-			pid := pids[rand.Int()%len(pids)]
+			pid := pids[randGen.Int()%len(pids)]
 			targetSlot := helpers.SlotToEpoch(attestations[0].Message.Aggregate.Data.Target.Epoch)
 			for _, p := range pids {
 				cs, err := s.p2p.Peers().ChainState(p)

beacon-chain/sync/pending_blocks_queue.go

@@ -11,12 +11,12 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/rand"
 	"github.com/prysmaticlabs/prysm/shared/runutil"
 	"github.com/prysmaticlabs/prysm/shared/slotutil"
 	"github.com/prysmaticlabs/prysm/shared/traceutil"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
-	"golang.org/x/exp/rand"
 )
 
 var processPendingBlocksPeriod = slotutil.DivideSlotBy(3 /* times per slot */)
@@ -51,6 +51,7 @@ func (s *Service) processPendingBlocks(ctx context.Context) error {
 		trace.Int64Attribute("numPeers", int64(len(pids))),
 	)
 
+	randGen := rand.NewGenerator()
 	for _, slot := range slots {
 		ctx, span := trace.StartSpan(ctx, "processPendingBlocks.InnerLoop")
 		span.AddAttributes(trace.Int64Attribute("slot", int64(slot)))
@@ -80,7 +81,7 @@ func (s *Service) processPendingBlocks(ctx context.Context) error {
 
 			// Start with a random peer to query, but choose the first peer in our unsorted list that claims to
 			// have a head slot newer than the block slot we are requesting.
-			pid := pids[rand.Int()%len(pids)]
+			pid := pids[randGen.Int()%len(pids)]
 			for _, p := range pids {
 				cs, err := s.p2p.Peers().ChainState(p)
 				if err != nil {