libs: remove most of libs/rand (#6364)

CHANGELOG_PENDING.md

@@ -46,6 +46,7 @@ Friendly reminder: We have a [bug bounty program](https://hackerone.com/tendermi
   - [rpc/client/http] \#6176 Remove `endpoint` arg from `New`, `NewWithTimeout` and `NewWithClient` (@melekes)
   - [rpc/client/http] \#6176 Unexpose `WSEvents` (@melekes)
   - [rpc/jsonrpc/client/ws_client] \#6176 `NewWS` no longer accepts options (use `NewWSWithOptions` and `OnReconnect` funcs to configure the client) (@melekes)
+  - [libs/rand] \#6364 Removed most of libs/rand in favour of standard lib's `math/rand` (@liamsi)
 
 - Blockchain Protocol
 

abci/client/socket_client_test.go

@@ -6,13 +6,14 @@ import (
 	"testing"
 	"time"
 
+	"math/rand"
+
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	abcicli "github.com/tendermint/tendermint/abci/client"
 	"github.com/tendermint/tendermint/abci/server"
 	"github.com/tendermint/tendermint/abci/types"
-	tmrand "github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/libs/service"
 )
 
@@ -101,7 +102,7 @@ func TestHangingSyncCalls(t *testing.T) {
 func setupClientServer(t *testing.T, app types.Application) (
 	service.Service, abcicli.Client) {
 	// some port between 20k and 30k
-	port := 20000 + tmrand.Int32()%10000
+	port := 20000 + rand.Int31()%10000
 	addr := fmt.Sprintf("localhost:%d", port)
 
 	s, err := server.NewServer(addr, "socket", app)

abci/example/kvstore/helpers.go

@@ -1,6 +1,8 @@
 package kvstore
 
 import (
+	mrand "math/rand"
+
 	"github.com/tendermint/tendermint/abci/types"
 	tmrand "github.com/tendermint/tendermint/libs/rand"
 )
@@ -9,7 +11,8 @@ import (
 // from the input value
 func RandVal(i int) types.ValidatorUpdate {
 	pubkey := tmrand.Bytes(32)
-	power := tmrand.Uint16() + 1
+	// Random value between [0, 2^16 - 1]
+	power := mrand.Uint32() & (1<<16 - 1) // nolint:gosec // G404: Use of weak random number generator
 	v := types.UpdateValidator(pubkey, int64(power), "")
 	return v
 }

abci/tests/server/client.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	mrand "math/rand"
 
 	abcicli "github.com/tendermint/tendermint/abci/client"
 	"github.com/tendermint/tendermint/abci/types"
@@ -18,7 +19,8 @@ func InitChain(client abcicli.Client) error {
 	vals := make([]types.ValidatorUpdate, total)
 	for i := 0; i < total; i++ {
 		pubkey := tmrand.Bytes(33)
-		power := tmrand.Int()
+		// nolint:gosec // G404: Use of weak random number generator
+		power := mrand.Int()
 		vals[i] = types.UpdateValidator(pubkey, int64(power), "")
 	}
 	_, err := client.InitChainSync(ctx, types.RequestInitChain{

blockchain/v0/pool_test.go

@@ -2,6 +2,7 @@ package v0
 
 import (
 	"fmt"
+	mrand "math/rand"
 	"testing"
 	"time"
 
@@ -67,7 +68,7 @@ func makePeers(numPeers int, minHeight, maxHeight int64) testPeers {
 	peers := make(testPeers, numPeers)
 	for i := 0; i < numPeers; i++ {
 		peerID := p2p.NodeID(tmrand.Str(12))
-		height := minHeight + tmrand.Int63n(maxHeight-minHeight)
+		height := minHeight + mrand.Int63n(maxHeight-minHeight)
 		base := minHeight + int64(i)
 		if base > height {
 			base = height

consensus/wal_generator.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	mrand "math/rand"
 	"path/filepath"
 	"testing"
 	"time"
@@ -15,7 +16,6 @@ import (
 	"github.com/tendermint/tendermint/abci/example/kvstore"
 	cfg "github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/libs/log"
-	tmrand "github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/privval"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
@@ -140,7 +140,8 @@ func WALWithNBlocks(t *testing.T, numBlocks int) (data []byte, err error) {
 func randPort() int {
 	// returns between base and base + spread
 	base, spread := 20000, 20000
-	return base + tmrand.Intn(spread)
+	// nolint:gosec // G404: Use of weak random number generator
+	return base + mrand.Intn(spread)
 }
 
 func makeAddrs() (string, string, string) {

libs/bits/bit_array.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"math"
+	mrand "math/rand"
 	"regexp"
 	"strings"
 	"sync"
@@ -24,6 +25,8 @@ type BitArray struct {
 // NewBitArray returns a new bit array.
 // It returns nil if the number of bits is zero.
 func NewBitArray(bits int) *BitArray {
+	// Reseed non-deterministically.
+	tmrand.Reseed()
 	if bits <= 0 {
 		return nil
 	}
@@ -242,7 +245,7 @@ func (bA *BitArray) IsFull() bool {
 
 // PickRandom returns a random index for a set bit in the bit array.
 // If there is no such value, it returns 0, false.
-// It uses the global randomness in `random.go` to get this index.
+// It uses math/rand's global randomness Source to get this index.
 func (bA *BitArray) PickRandom() (int, bool) {
 	if bA == nil {
 		return 0, false
@@ -255,8 +258,8 @@ func (bA *BitArray) PickRandom() (int, bool) {
 	if len(trueIndices) == 0 { // no bits set to true
 		return 0, false
 	}
-
-	return trueIndices[tmrand.Intn(len(trueIndices))], true
+	// nolint:gosec // G404: Use of weak random number generator
+	return trueIndices[mrand.Intn(len(trueIndices))], true
 }
 
 func (bA *BitArray) getTrueIndices() []int {

libs/clist/clist_test.go

@@ -2,14 +2,13 @@ package clist
 
 import (
 	"fmt"
+	mrand "math/rand"
 	"runtime"
 	"sync/atomic"
 	"testing"
 	"time"
 
 	"github.com/stretchr/testify/assert"
-
-	tmrand "github.com/tendermint/tendermint/libs/rand"
 )
 
 func TestPanicOnMaxLength(t *testing.T) {
@@ -148,7 +147,7 @@ func _TestGCRandom(t *testing.T) {
 		els = append(els, el)
 	}
 
-	for _, i := range tmrand.Perm(numElements) {
+	for _, i := range mrand.Perm(numElements) {
 		el := els[i]
 		l.Remove(el)
 		_ = el.Next()
@@ -206,7 +205,7 @@ func TestScanRightDeleteRandom(t *testing.T) {
 	// Remove an element, push back an element.
 	for i := 0; i < numTimes; i++ {
 		// Pick an element to remove
-		rmElIdx := tmrand.Intn(len(els))
+		rmElIdx := mrand.Intn(len(els))
 		rmEl := els[rmElIdx]
 
 		// Remove it
@@ -260,7 +259,7 @@ func TestWaitChan(t *testing.T) {
 		for i := 1; i < 100; i++ {
 			l.PushBack(i)
 			pushed++
-			time.Sleep(time.Duration(tmrand.Intn(25)) * time.Millisecond)
+			time.Sleep(time.Duration(mrand.Intn(25)) * time.Millisecond)
 		}
 		// apply a deterministic pause so the counter has time to catch up
 		time.Sleep(25 * time.Millisecond)

libs/rand/random.go

@@ -2,161 +2,57 @@ package rand
 
 import (
 	crand "crypto/rand"
+	"encoding/binary"
+	"fmt"
 	mrand "math/rand"
-	"time"
-
-	tmsync "github.com/tendermint/tendermint/libs/sync"
 )
 
 const (
 	strChars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" // 62 characters
 )
 
-// Rand is a prng, that is seeded with OS randomness.
-// The OS randomness is obtained from crypto/rand, however none of the provided
-// methods are suitable for cryptographic usage.
-// They all utilize math/rand's prng internally.
-//
-// All of the methods here are suitable for concurrent use.
-// This is achieved by using a mutex lock on all of the provided methods.
-type Rand struct {
-	tmsync.Mutex
-	rand *mrand.Rand
-}
-
-var grand *Rand
-
 func init() {
-	grand = NewRand()
-	grand.init()
+	Reseed()
 }
 
-func NewRand() *Rand {
-	rand := &Rand{}
-	rand.init()
-	return rand
+// NewRand returns a prng, that is seeded with OS randomness.
+// The OS randomness is obtained from crypto/rand, however, like with any math/rand.Rand
+// object none of the provided methods are suitable for cryptographic usage.
+//
+// Note that the returned instance of math/rand's Rand is not
+// suitable for concurrent use by multiple goroutines.
+//
+// For concurrent use, call Reseed to reseed math/rand's default source and
+// use math/rand's top-level convenience functions instead.
+func NewRand() *mrand.Rand {
+	seed := crandSeed()
+	// nolint:gosec // G404: Use of weak random number generator
+	return mrand.New(mrand.NewSource(seed))
 }
 
-func (r *Rand) init() {
-	bz := cRandBytes(8)
-	var seed uint64
-	for i := 0; i < 8; i++ {
-		seed |= uint64(bz[i])
-		seed <<= 8
-	}
-	r.reset(int64(seed))
-}
-
-func (r *Rand) reset(seed int64) {
-	r.rand = mrand.New(mrand.NewSource(seed)) // nolint:gosec // G404: Use of weak random number generator
-}
-
-//----------------------------------------
-// Global functions
-
-func Seed(seed int64) {
-	grand.Seed(seed)
+// Reseed conveniently re-seeds the default Source of math/rand with
+// randomness obtained from crypto/rand.
+//
+// Note that this does not make math/rand suitable for cryptographic usage.
+//
+// Use math/rand's top-level convenience functions remain suitable
+// for concurrent use by multiple goroutines.
+func Reseed() {
+	seed := crandSeed()
+	mrand.Seed(seed)
 }
 
+// Str constructs a random alphanumeric string of given length
+// from math/rand's global default Source.
 func Str(length int) string {
-	return grand.Str(length)
-}
-
-func Uint16() uint16 {
-	return grand.Uint16()
-}
-
-func Uint32() uint32 {
-	return grand.Uint32()
-}
-
-func Uint64() uint64 {
-	return grand.Uint64()
-}
-
-func Uint() uint {
-	return grand.Uint()
-}
-
-func Int16() int16 {
-	return grand.Int16()
-}
-
-func Int32() int32 {
-	return grand.Int32()
-}
-
-func Int64() int64 {
-	return grand.Int64()
-}
-
-func Int() int {
-	return grand.Int()
-}
-
-func Int31() int32 {
-	return grand.Int31()
-}
-
-func Int31n(n int32) int32 {
-	return grand.Int31n(n)
-}
-
-func Int63() int64 {
-	return grand.Int63()
-}
-
-func Int63n(n int64) int64 {
-	return grand.Int63n(n)
-}
-
-func Bool() bool {
-	return grand.Bool()
-}
-
-func Float32() float32 {
-	return grand.Float32()
-}
-
-func Float64() float64 {
-	return grand.Float64()
-}
-
-func Time() time.Time {
-	return grand.Time()
-}
-
-func Bytes(n int) []byte {
-	return grand.Bytes(n)
-}
-
-func Intn(n int) int {
-	return grand.Intn(n)
-}
-
-func Perm(n int) []int {
-	return grand.Perm(n)
-}
-
-//----------------------------------------
-// Rand methods
-
-func (r *Rand) Seed(seed int64) {
-	r.Lock()
-	r.reset(seed)
-	r.Unlock()
-}
-
-// Str constructs a random alphanumeric string of given length.
-func (r *Rand) Str(length int) string {
 	if length <= 0 {
 		return ""
 	}
 
-	chars := []byte{}
-MAIN_LOOP:
+	chars := make([]byte, 0, length)
 	for {
-		val := r.Int63()
+		// nolint:gosec // G404: Use of weak random number generator
+		val := mrand.Int63()
 		for i := 0; i < 10; i++ {
 			v := int(val & 0x3f) // rightmost 6 bits
 			if v >= 62 {         // only 62 characters in strChars
@@ -165,147 +61,29 @@ MAIN_LOOP:
 			} else {
 				chars = append(chars, strChars[v])
 				if len(chars) == length {
-					break MAIN_LOOP
+					return string(chars)
 				}
 				val >>= 6
 			}
 		}
 	}
-
-	return string(chars)
 }
 
-func (r *Rand) Uint16() uint16 {
-	return uint16(r.Uint32() & (1<<16 - 1))
-}
-
-func (r *Rand) Uint32() uint32 {
-	r.Lock()
-	u32 := r.rand.Uint32()
-	r.Unlock()
-	return u32
-}
-
-func (r *Rand) Uint64() uint64 {
-	return uint64(r.Uint32())<<32 + uint64(r.Uint32())
-}
-
-func (r *Rand) Uint() uint {
-	r.Lock()
-	i := r.rand.Int()
-	r.Unlock()
-	return uint(i)
-}
-
-func (r *Rand) Int16() int16 {
-	return int16(r.Uint32() & (1<<16 - 1))
-}
-
-func (r *Rand) Int32() int32 {
-	return int32(r.Uint32())
-}
-
-func (r *Rand) Int64() int64 {
-	return int64(r.Uint64())
-}
-
-func (r *Rand) Int() int {
-	r.Lock()
-	i := r.rand.Int()
-	r.Unlock()
-	return i
-}
-
-func (r *Rand) Int31() int32 {
-	r.Lock()
-	i31 := r.rand.Int31()
-	r.Unlock()
-	return i31
-}
-
-func (r *Rand) Int31n(n int32) int32 {
-	r.Lock()
-	i31n := r.rand.Int31n(n)
-	r.Unlock()
-	return i31n
-}
-
-func (r *Rand) Int63() int64 {
-	r.Lock()
-	i63 := r.rand.Int63()
-	r.Unlock()
-	return i63
-}
-
-func (r *Rand) Int63n(n int64) int64 {
-	r.Lock()
-	i63n := r.rand.Int63n(n)
-	r.Unlock()
-	return i63n
-}
-
-func (r *Rand) Float32() float32 {
-	r.Lock()
-	f32 := r.rand.Float32()
-	r.Unlock()
-	return f32
-}
-
-func (r *Rand) Float64() float64 {
-	r.Lock()
-	f64 := r.rand.Float64()
-	r.Unlock()
-	return f64
-}
-
-func (r *Rand) Time() time.Time {
-	return time.Unix(int64(r.Uint64()), 0)
-}
-
-// Bytes returns n random bytes generated from the internal
-// prng.
-func (r *Rand) Bytes(n int) []byte {
-	// cRandBytes isn't guaranteed to be fast so instead
-	// use random bytes generated from the internal PRNG
+// Bytes returns n random bytes generated from math/rand's global default Source.
+func Bytes(n int) []byte {
 	bs := make([]byte, n)
 	for i := 0; i < len(bs); i++ {
-		bs[i] = byte(r.Int() & 0xFF)
+		// nolint:gosec // G404: Use of weak random number generator
+		bs[i] = byte(mrand.Int() & 0xFF)
 	}
 	return bs
 }
 
-// Intn returns, as an int, a uniform pseudo-random number in the range [0, n).
-// It panics if n <= 0.
-func (r *Rand) Intn(n int) int {
-	r.Lock()
-	i := r.rand.Intn(n)
-	r.Unlock()
-	return i
-}
-
-// Bool returns a uniformly random boolean
-func (r *Rand) Bool() bool {
-	// See https://github.com/golang/go/issues/23804#issuecomment-365370418
-	// for reasoning behind computing like this
-	return r.Int63()%2 == 0
-}
-
-// Perm returns a pseudo-random permutation of n integers in [0, n).
-func (r *Rand) Perm(n int) []int {
-	r.Lock()
-	perm := r.rand.Perm(n)
-	r.Unlock()
-	return perm
-}
-
-// NOTE: This relies on the os's random number generator.
-// For real security, we should salt that with some seed.
-// See github.com/tendermint/tendermint/crypto for a more secure reader.
-func cRandBytes(numBytes int) []byte {
-	b := make([]byte, numBytes)
-	_, err := crand.Read(b)
+func crandSeed() int64 {
+	var seed int64
+	err := binary.Read(crand.Reader, binary.BigEndian, &seed)
 	if err != nil {
-		panic(err)
+		panic(fmt.Sprintf("could nor read random seed from crypto/rand: %v", err))
 	}
-	return b
+	return seed
 }

libs/rand/random_test.go

@@ -1,13 +1,7 @@
 package rand
 
 import (
-	"bytes"
-	"encoding/json"
-	"fmt"
-	mrand "math/rand"
-	"sync"
 	"testing"
-	"time"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -24,71 +18,6 @@ func TestRandBytes(t *testing.T) {
 	assert.Equal(t, l, len(b))
 }
 
-func TestRandIntn(t *testing.T) {
-	n := 243
-	for i := 0; i < 100; i++ {
-		x := Intn(n)
-		assert.True(t, x < n)
-	}
-}
-
-// Test to make sure that we never call math.rand().
-// We do this by ensuring that outputs are deterministic.
-func TestDeterminism(t *testing.T) {
-	var firstOutput string
-
-	// Set math/rand's seed for the sake of debugging this test.
-	// (It isn't strictly necessary).
-	mrand.Seed(1)
-
-	for i := 0; i < 100; i++ {
-		output := testThemAll()
-		if i == 0 {
-			firstOutput = output
-		} else if firstOutput != output {
-			t.Errorf("run #%d's output was different from first run.\nfirst: %v\nlast: %v",
-				i, firstOutput, output)
-		}
-	}
-}
-
-func testThemAll() string {
-
-	// Such determinism.
-	grand.reset(1)
-
-	// Use it.
-	out := new(bytes.Buffer)
-	perm := Perm(10)
-	blob, _ := json.Marshal(perm)
-	fmt.Fprintf(out, "perm: %s\n", blob)
-	fmt.Fprintf(out, "randInt: %d\n", Int())
-	fmt.Fprintf(out, "randUint: %d\n", Uint())
-	fmt.Fprintf(out, "randIntn: %d\n", Intn(97))
-	fmt.Fprintf(out, "randInt31: %d\n", Int31())
-	fmt.Fprintf(out, "randInt32: %d\n", Int32())
-	fmt.Fprintf(out, "randInt63: %d\n", Int63())
-	fmt.Fprintf(out, "randInt64: %d\n", Int64())
-	fmt.Fprintf(out, "randUint32: %d\n", Uint32())
-	fmt.Fprintf(out, "randUint64: %d\n", Uint64())
-	return out.String()
-}
-
-func TestRngConcurrencySafety(t *testing.T) {
-	var wg sync.WaitGroup
-	for i := 0; i < 100; i++ {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-
-			_ = Uint64()
-			<-time.After(time.Millisecond * time.Duration(Intn(100)))
-			_ = Perm(3)
-		}()
-	}
-	wg.Wait()
-}
-
 func BenchmarkRandBytes10B(b *testing.B) {
 	benchmarkRandBytes(b, 10)
 }

libs/tempfile/tempfile_test.go

@@ -6,6 +6,7 @@ import (
 	"bytes"
 	"fmt"
 	"io/ioutil"
+	mrand "math/rand"
 	"os"
 	testing "testing"
 
@@ -16,8 +17,8 @@ import (
 
 func TestWriteFileAtomic(t *testing.T) {
 	var (
-		data             = []byte(tmrand.Str(tmrand.Intn(2048)))
-		old              = tmrand.Bytes(tmrand.Intn(2048))
+		data             = []byte(tmrand.Str(mrand.Intn(2048)))
+		old              = tmrand.Bytes(mrand.Intn(2048))
 		perm os.FileMode = 0600
 	)
 

libs/test/mutate.go

@@ -1,7 +1,8 @@
+// nolint:gosec // G404: Use of weak random number generator
 package test
 
 import (
-	tmrand "github.com/tendermint/tendermint/libs/rand"
+	mrand "math/rand"
 )
 
 // Contract: !bytes.Equal(input, output) && len(input) >= len(output)
@@ -17,11 +18,11 @@ func MutateByteSlice(bytez []byte) []byte {
 	bytez = mBytez
 
 	// Try a random mutation
-	switch tmrand.Int() % 2 {
+	switch mrand.Int() % 2 {
 	case 0: // Mutate a single byte
-		bytez[tmrand.Int()%len(bytez)] += byte(tmrand.Int()%255 + 1)
+		bytez[mrand.Int()%len(bytez)] += byte(mrand.Int()%255 + 1)
 	case 1: // Remove an arbitrary byte
-		pos := tmrand.Int() % len(bytez)
+		pos := mrand.Int() % len(bytez)
 		bytez = append(bytez[:pos], bytez[pos+1:]...)
 	}
 	return bytez

p2p/conn/secret_connection_test.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
+	mrand "math/rand"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -114,8 +115,8 @@ func TestSecretConnectionReadWrite(t *testing.T) {
 
 	// Pre-generate the things to write (for foo & bar)
 	for i := 0; i < 100; i++ {
-		fooWrites = append(fooWrites, tmrand.Str((tmrand.Int()%(dataMaxSize*5))+1))
-		barWrites = append(barWrites, tmrand.Str((tmrand.Int()%(dataMaxSize*5))+1))
+		fooWrites = append(fooWrites, tmrand.Str((mrand.Int()%(dataMaxSize*5))+1))
+		barWrites = append(barWrites, tmrand.Str((mrand.Int()%(dataMaxSize*5))+1))
 	}
 
 	// A helper that will run with (fooConn, fooWrites, fooReads) and vice versa
@@ -312,7 +313,7 @@ func createGoldenTestVectors(t *testing.T) string {
 		randSecret := new([32]byte)
 		copy((*randSecret)[:], randSecretVector)
 		data += hex.EncodeToString((*randSecret)[:]) + ","
-		locIsLeast := tmrand.Bool()
+		locIsLeast := mrand.Int63()%2 == 0
 		data += strconv.FormatBool(locIsLeast) + ","
 		recvSecret, sendSecret := deriveSecrets(randSecret, locIsLeast)
 		data += hex.EncodeToString((*recvSecret)[:]) + ","
@@ -412,7 +413,7 @@ func BenchmarkWriteSecretConnection(b *testing.B) {
 
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
-		idx := tmrand.Intn(len(fooWriteBytes))
+		idx := mrand.Intn(len(fooWriteBytes))
 		_, err := fooSecConn.Write(fooWriteBytes[idx])
 		if err != nil {
 			b.Errorf("failed to write to fooSecConn: %v", err)
@@ -446,7 +447,7 @@ func BenchmarkReadSecretConnection(b *testing.B) {
 	}
 	go func() {
 		for i := 0; i < b.N; i++ {
-			idx := tmrand.Intn(len(fooWriteBytes))
+			idx := mrand.Intn(len(fooWriteBytes))
 			_, err := fooSecConn.Write(fooWriteBytes[idx])
 			if err != nil {
 				b.Errorf("failed to write to fooSecConn: %v, %v,%v", err, i, b.N)

p2p/pex/addrbook.go

@@ -9,13 +9,12 @@ import (
 	"encoding/binary"
 	"fmt"
 	"math"
-	"math/rand"
+	mrand "math/rand"
 	"net"
 	"sync"
 	"time"
 
 	"github.com/minio/highwayhash"
-
 	"github.com/tendermint/tendermint/crypto"
 	tmmath "github.com/tendermint/tendermint/libs/math"
 	tmrand "github.com/tendermint/tendermint/libs/rand"
@@ -89,7 +88,6 @@ type addrBook struct {
 
 	// accessed concurrently
 	mtx        tmsync.Mutex
-	rand       *tmrand.Rand
 	ourAddrs   map[string]struct{}
 	privateIDs map[p2p.NodeID]struct{}
 	addrLookup map[p2p.NodeID]*knownAddress // new & old
@@ -118,7 +116,6 @@ func newHashKey() []byte {
 // Use Start to begin processing asynchronous address updates.
 func NewAddrBook(filePath string, routabilityStrict bool) AddrBook {
 	am := &addrBook{
-		rand:              tmrand.NewRand(),
 		ourAddrs:          make(map[string]struct{}),
 		privateIDs:        make(map[p2p.NodeID]struct{}),
 		addrLookup:        make(map[p2p.NodeID]*knownAddress),
@@ -268,6 +265,7 @@ func (a *addrBook) Empty() bool {
 // and determines how biased we are to pick an address from a new bucket.
 // PickAddress returns nil if the AddrBook is empty or if we try to pick
 // from an empty bucket.
+// nolint:gosec // G404: Use of weak random number generator
 func (a *addrBook) PickAddress(biasTowardsNewAddrs int) *p2p.NetAddress {
 	a.mtx.Lock()
 	defer a.mtx.Unlock()
@@ -292,7 +290,7 @@ func (a *addrBook) PickAddress(biasTowardsNewAddrs int) *p2p.NetAddress {
 
 	// pick a random peer from a random bucket
 	var bucket map[string]*knownAddress
-	pickFromOldBucket := (newCorrelation+oldCorrelation)*a.rand.Float64() < oldCorrelation
+	pickFromOldBucket := (newCorrelation+oldCorrelation)*mrand.Float64() < oldCorrelation
 	if (pickFromOldBucket && a.nOld == 0) ||
 		(!pickFromOldBucket && a.nNew == 0) {
 		return nil
@@ -300,13 +298,13 @@ func (a *addrBook) PickAddress(biasTowardsNewAddrs int) *p2p.NetAddress {
 	// loop until we pick a random non-empty bucket
 	for len(bucket) == 0 {
 		if pickFromOldBucket {
-			bucket = a.bucketsOld[a.rand.Intn(len(a.bucketsOld))]
+			bucket = a.bucketsOld[mrand.Intn(len(a.bucketsOld))]
 		} else {
-			bucket = a.bucketsNew[a.rand.Intn(len(a.bucketsNew))]
+			bucket = a.bucketsNew[mrand.Intn(len(a.bucketsNew))]
 		}
 	}
 	// pick a random index and loop over the map to return that index
-	randIndex := a.rand.Intn(len(bucket))
+	randIndex := mrand.Intn(len(bucket))
 	for _, ka := range bucket {
 		if randIndex == 0 {
 			return ka.Addr
@@ -417,7 +415,8 @@ func (a *addrBook) GetSelection() []*p2p.NetAddress {
 	// `numAddresses' since we are throwing the rest.
 	for i := 0; i < numAddresses; i++ {
 		// pick a number between current index and the end
-		j := tmrand.Intn(len(allAddr)-i) + i
+		// nolint:gosec // G404: Use of weak random number generator
+		j := mrand.Intn(len(allAddr)-i) + i
 		allAddr[i], allAddr[j] = allAddr[j], allAddr[i]
 	}
 
@@ -681,7 +680,8 @@ func (a *addrBook) addAddress(addr, src *p2p.NetAddress) error {
 		}
 		// The more entries we have, the less likely we are to add more.
 		factor := int32(2 * len(ka.Buckets))
-		if a.rand.Int31n(factor) != 0 {
+		// nolint:gosec // G404: Use of weak random number generator
+		if mrand.Int31n(factor) != 0 {
 			return nil
 		}
 	} else {
@@ -717,6 +717,7 @@ func (a *addrBook) randomPickAddresses(bucketType byte, num int) []*p2p.NetAddre
 	}
 	selection := make([]*p2p.NetAddress, 0, num)
 	chosenSet := make(map[string]bool, num)
+	rand := tmrand.NewRand()
 	rand.Shuffle(total, func(i, j int) {
 		addresses[i], addresses[j] = addresses[j], addresses[i]
 	})

p2p/pex/addrbook_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"math"
+	mrand "math/rand"
 	"net"
 	"os"
 	"testing"
@@ -187,12 +188,12 @@ func randNetAddressPairs(t *testing.T, n int) []netAddressPair {
 func randIPv4Address(t *testing.T) *p2p.NetAddress {
 	for {
 		ip := fmt.Sprintf("%v.%v.%v.%v",
-			tmrand.Intn(254)+1,
-			tmrand.Intn(255),
-			tmrand.Intn(255),
-			tmrand.Intn(255),
+			mrand.Intn(254)+1,
+			mrand.Intn(255),
+			mrand.Intn(255),
+			mrand.Intn(255),
 		)
-		port := tmrand.Intn(65535-1) + 1
+		port := mrand.Intn(65535-1) + 1
 		id := p2p.NodeID(hex.EncodeToString(tmrand.Bytes(p2p.NodeIDByteLength)))
 		idAddr := p2p.IDAddressString(id, fmt.Sprintf("%v:%v", ip, port))
 		addr, err := p2p.NewNetAddressString(idAddr)
@@ -554,7 +555,7 @@ func TestMultipleAddrBookAddressSelection(t *testing.T) {
 	ranges := [...][]int{{33, 100}, {100, 175}}
 	bookSizes := make([]int, 0, len(ranges))
 	for _, r := range ranges {
-		bookSizes = append(bookSizes, tmrand.Intn(r[1]-r[0])+r[0])
+		bookSizes = append(bookSizes, mrand.Intn(r[1]-r[0])+r[0])
 	}
 	t.Logf("Testing address selection for the following book sizes %v\n", bookSizes)
 	for _, bookSize := range bookSizes {

p2p/pex/pex_reactor.go

@@ -525,7 +525,8 @@ func (r *Reactor) ensurePeers() {
 		peers := r.Switch.Peers().List()
 		peersCount := len(peers)
 		if peersCount > 0 {
-			peer := peers[tmrand.Int()%peersCount]
+			rand := tmrand.NewRand()
+			peer := peers[rand.Int()%peersCount]
 			r.Logger.Info("We need more addresses. Sending pexRequest to random peer", "peer", peer)
 			r.RequestAddrs(peer)
 		}
@@ -558,7 +559,8 @@ func (r *Reactor) dialPeer(addr *p2p.NetAddress) error {
 
 	// exponential backoff if it's not our first attempt to dial given address
 	if attempts > 0 {
-		jitter := time.Duration(tmrand.Float64() * float64(time.Second)) // 1s == (1e9 ns)
+		rand := tmrand.NewRand()
+		jitter := time.Duration(rand.Float64() * float64(time.Second)) // 1s == (1e9 ns)
 		backoffDuration := jitter + ((1 << uint(attempts)) * time.Second)
 		backoffDuration = r.maxBackoffDurationForPeer(addr, backoffDuration)
 		sinceLastDialed := time.Since(lastDialed)
@@ -624,7 +626,8 @@ func (r *Reactor) checkSeeds() (numOnline int, netAddrs []*p2p.NetAddress, err e
 
 // randomly dial seeds until we connect to one or exhaust them
 func (r *Reactor) dialSeeds() {
-	perm := tmrand.Perm(len(r.seedAddrs))
+	rand := tmrand.NewRand()
+	perm := rand.Perm(len(r.seedAddrs))
 	// perm := r.Switch.rng.Perm(lSeeds)
 	for _, i := range perm {
 		// dial a random seed

p2p/switch.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"math"
+	mrand "math/rand"
 	"net"
 	"sync"
 	"time"
@@ -12,7 +13,7 @@ import (
 	"github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/libs/cmap"
-	"github.com/tendermint/tendermint/libs/rand"
+	tmrand "github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/libs/service"
 	"github.com/tendermint/tendermint/p2p/conn"
 )
@@ -115,8 +116,6 @@ type Switch struct {
 	connFilters   []ConnFilterFunc
 	conns         ConnSet
 
-	rng *rand.Rand // seed for randomizing dial times and orders
-
 	metrics *Metrics
 }
 
@@ -159,8 +158,8 @@ func NewSwitch(
 		conns:                NewConnSet(),
 	}
 
-	// Ensure we have a completely undeterministic PRNG.
-	sw.rng = rand.NewRand()
+	// Ensure PRNG is reseeded.
+	tmrand.Reseed()
 
 	sw.BaseService = *service.NewBaseService(nil, "P2P Switch", sw)
 
@@ -554,7 +553,7 @@ func (sw *Switch) dialPeersAsync(netAddrs []*NetAddress) {
 	}
 
 	// permute the list, dial them in random order.
-	perm := sw.rng.Perm(len(netAddrs))
+	perm := mrand.Perm(len(netAddrs))
 	for i := 0; i < len(perm); i++ {
 		go func(i int) {
 			j := perm[i]
@@ -597,7 +596,8 @@ func (sw *Switch) DialPeerWithAddress(addr *NetAddress) error {
 
 // sleep for interval plus some random amount of ms on [0, dialRandomizerIntervalMilliseconds]
 func (sw *Switch) randomSleep(interval time.Duration) {
-	r := time.Duration(sw.rng.Int63n(dialRandomizerIntervalMilliseconds)) * time.Millisecond
+	// nolint:gosec // G404: Use of weak random number generator
+	r := time.Duration(mrand.Int63n(dialRandomizerIntervalMilliseconds)) * time.Millisecond
 	time.Sleep(r + interval)
 }
 

p2p/test_util.go

@@ -3,6 +3,7 @@ package p2p
 import (
 	"context"
 	"fmt"
+	mrand "math/rand"
 	"net"
 
 	"github.com/tendermint/tendermint/libs/log"
@@ -35,15 +36,16 @@ func CreateRandomPeer(outbound bool) Peer {
 	return p
 }
 
+// nolint:gosec // G404: Use of weak random number generator
 func CreateRoutableAddr() (addr string, netAddr *NetAddress) {
 	for {
 		var err error
 		addr = fmt.Sprintf("%X@%v.%v.%v.%v:26656",
 			tmrand.Bytes(20),
-			tmrand.Int()%256,
-			tmrand.Int()%256,
-			tmrand.Int()%256,
-			tmrand.Int()%256)
+			mrand.Int()%256,
+			mrand.Int()%256,
+			mrand.Int()%256,
+			mrand.Int()%256)
 		netAddr, err = NewNetAddressString(addr)
 		if err != nil {
 			panic(err)

rpc/jsonrpc/client/ws_client.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	mrand "math/rand"
 	"net"
 	"net/http"
 	"sync"
@@ -12,7 +13,6 @@ import (
 	"github.com/gorilla/websocket"
 	metrics "github.com/rcrowley/go-metrics"
 
-	tmrand "github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/libs/service"
 	tmsync "github.com/tendermint/tendermint/libs/sync"
 	types "github.com/tendermint/tendermint/rpc/jsonrpc/types"
@@ -266,7 +266,8 @@ func (c *WSClient) reconnect() error {
 	}()
 
 	for {
-		jitter := time.Duration(tmrand.Float64() * float64(time.Second)) // 1s == (1e9 ns)
+		// nolint:gosec // G404: Use of weak random number generator
+		jitter := time.Duration(mrand.Float64() * float64(time.Second)) // 1s == (1e9 ns)
 		backoffDuration := jitter + ((1 << attempt) * time.Second)
 
 		c.Logger.Info("reconnecting", "attempt", attempt+1, "backoff_duration", backoffDuration)

rpc/jsonrpc/jsonrpc_test.go

@@ -6,6 +6,7 @@ import (
 	crand "crypto/rand"
 	"encoding/json"
 	"fmt"
+	mrand "math/rand"
 	"net/http"
 	"os"
 	"os/exec"
@@ -18,8 +19,6 @@ import (
 
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
 	"github.com/tendermint/tendermint/libs/log"
-	tmrand "github.com/tendermint/tendermint/libs/rand"
-
 	client "github.com/tendermint/tendermint/rpc/jsonrpc/client"
 	server "github.com/tendermint/tendermint/rpc/jsonrpc/server"
 	types "github.com/tendermint/tendermint/rpc/jsonrpc/types"
@@ -215,7 +214,7 @@ func testWithHTTPClient(t *testing.T, cl client.HTTPClient) {
 	require.Nil(t, err)
 	assert.Equal(t, got3, val3)
 
-	val4 := tmrand.Intn(10000)
+	val4 := mrand.Intn(10000)
 	got4, err := echoIntViaHTTP(cl, val4)
 	require.Nil(t, err)
 	assert.Equal(t, got4, val4)
@@ -400,7 +399,7 @@ func TestWSClientPingPong(t *testing.T) {
 }
 
 func randBytes(t *testing.T) []byte {
-	n := tmrand.Intn(10) + 2
+	n := mrand.Intn(10) + 2
 	buf := make([]byte, n)
 	_, err := crand.Read(buf)
 	require.Nil(t, err)

state/state_test.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"math"
 	"math/big"
+	mrand "math/rand"
 	"os"
 	"testing"
 
@@ -18,7 +19,6 @@ import (
 	cfg "github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/crypto/ed25519"
 	cryptoenc "github.com/tendermint/tendermint/crypto/encoding"
-	tmrand "github.com/tendermint/tendermint/libs/rand"
 	tmstate "github.com/tendermint/tendermint/proto/tendermint/state"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
@@ -356,18 +356,18 @@ func TestProposerFrequency(t *testing.T) {
 	maxPower := 1000
 	nTestCases := 5
 	for i := 0; i < nTestCases; i++ {
-		N := tmrand.Int()%maxVals + 1
+		N := mrand.Int()%maxVals + 1
 		vals := make([]*types.Validator, N)
 		totalVotePower := int64(0)
 		for j := 0; j < N; j++ {
 			// make sure votePower > 0
-			votePower := int64(tmrand.Int()%maxPower) + 1
+			votePower := int64(mrand.Int()%maxPower) + 1
 			totalVotePower += votePower
 			privVal := types.NewMockPV()
 			pubKey, err := privVal.GetPubKey(context.Background())
 			require.NoError(t, err)
 			val := types.NewValidator(pubKey, votePower)
-			val.ProposerPriority = tmrand.Int64()
+			val.ProposerPriority = mrand.Int63()
 			vals[j] = val
 		}
 		valSet := types.NewValidatorSet(vals)
@@ -384,7 +384,7 @@ func genValSetWithPowers(powers []int64) *types.ValidatorSet {
 	for i := 0; i < size; i++ {
 		totalVotePower += powers[i]
 		val := types.NewValidator(ed25519.GenPrivKey().PubKey(), powers[i])
-		val.ProposerPriority = tmrand.Int64()
+		val.ProposerPriority = mrand.Int63()
 		vals[i] = val
 	}
 	valSet := types.NewValidatorSet(vals)

types/block_test.go

@@ -7,6 +7,7 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"math"
+	mrand "math/rand"
 	"os"
 	"reflect"
 	"testing"
@@ -643,7 +644,7 @@ func TestBlockIDValidateBasic(t *testing.T) {
 }
 
 func TestBlockProtoBuf(t *testing.T) {
-	h := tmrand.Int63()
+	h := mrand.Int63()
 	c1 := randCommit(time.Now())
 	b1 := MakeBlock(h, []Tx{Tx([]byte{1})}, &Commit{Signatures: []CommitSig{}}, []Evidence{})
 	b1.ProposerAddress = tmrand.Bytes(crypto.AddressSize)
@@ -751,7 +752,7 @@ func TestEvidenceDataProtoBuf(t *testing.T) {
 func makeRandHeader() Header {
 	chainID := "test"
 	t := time.Now()
-	height := tmrand.Int63()
+	height := mrand.Int63()
 	randBytes := tmrand.Bytes(tmhash.Size)
 	randAddress := tmrand.Bytes(crypto.AddressSize)
 	h := Header{

types/event_bus_test.go

@@ -3,7 +3,7 @@ package types
 import (
 	"context"
 	"fmt"
-	"math/rand"
+	mrand "math/rand"
 	"testing"
 	"time"
 
@@ -13,7 +13,6 @@ import (
 	abci "github.com/tendermint/tendermint/abci/types"
 	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	tmquery "github.com/tendermint/tendermint/libs/pubsub/query"
-	tmrand "github.com/tendermint/tendermint/libs/rand"
 )
 
 func TestEventBusPublishEventTx(t *testing.T) {
@@ -410,7 +409,7 @@ func BenchmarkEventBus(b *testing.B) {
 
 func benchmarkEventBus(numClients int, randQueries bool, randEvents bool, b *testing.B) {
 	// for random* functions
-	rand.Seed(time.Now().Unix())
+	mrand.Seed(time.Now().Unix())
 
 	eventBus := NewEventBusWithBufferCapacity(0) // set buffer capacity to 0 so we are not testing cache
 	err := eventBus.Start()
@@ -476,7 +475,7 @@ var events = []string{
 	EventVote}
 
 func randEvent() string {
-	return events[tmrand.Intn(len(events))]
+	return events[mrand.Intn(len(events))]
 }
 
 var queries = []tmpubsub.Query{
@@ -494,5 +493,5 @@ var queries = []tmpubsub.Query{
 	EventQueryVote}
 
 func randQuery() tmpubsub.Query {
-	return queries[tmrand.Intn(len(queries))]
+	return queries[mrand.Intn(len(queries))]
 }

types/evidence_test.go

@@ -3,6 +3,7 @@ package types
 import (
 	"context"
 	"math"
+	mrand "math/rand"
 	"testing"
 	"time"
 
@@ -256,7 +257,7 @@ func makeHeaderRandom() *Header {
 	return &Header{
 		Version:            version.Consensus{Block: version.BlockProtocol, App: 1},
 		ChainID:            tmrand.Str(12),
-		Height:             int64(tmrand.Uint16()) + 1,
+		Height:             int64(mrand.Uint32() + 1),
 		Time:               time.Now(),
 		LastBlockID:        makeBlockIDRandom(),
 		LastCommitHash:     crypto.CRandBytes(tmhash.Size),

types/tx_test.go

@@ -2,6 +2,7 @@ package types
 
 import (
 	"bytes"
+	mrand "math/rand"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -21,7 +22,7 @@ func makeTxs(cnt, size int) Txs {
 }
 
 func randInt(low, high int) int {
-	off := tmrand.Int() % (high - low)
+	off := mrand.Int() % (high - low)
 	return low + off
 }
 

types/validator.go

@@ -5,11 +5,11 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	mrand "math/rand"
 	"strings"
 
 	"github.com/tendermint/tendermint/crypto"
 	ce "github.com/tendermint/tendermint/crypto/encoding"
-	tmrand "github.com/tendermint/tendermint/libs/rand"
 	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
 )
 
@@ -183,7 +183,8 @@ func RandValidator(randPower bool, minPower int64) (*Validator, PrivValidator) {
 	privVal := NewMockPV()
 	votePower := minPower
 	if randPower {
-		votePower += int64(tmrand.Uint32())
+		// nolint:gosec // G404: Use of weak random number generator
+		votePower += int64(mrand.Uint32())
 	}
 	pubKey, err := privVal.GetPubKey(context.Background())
 	if err != nil {

types/validator_set_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 	"math"
+	"math/rand"
 	"sort"
 	"strings"
 	"testing"
@@ -352,10 +353,10 @@ func TestProposerSelection3(t *testing.T) {
 
 		// times is usually 1
 		times := int32(1)
-		mod := (tmrand.Int() % 5) + 1
-		if tmrand.Int()%mod > 0 {
+		mod := (rand.Int() % 5) + 1
+		if rand.Int()%mod > 0 {
 			// sometimes its up to 5
-			times = (tmrand.Int31() % 4) + 1
+			times = (rand.Int31() % 4) + 1
 		}
 		vset.IncrementProposerPriority(times)
 
@@ -376,8 +377,8 @@ func randPubKey() crypto.PubKey {
 func randValidator(totalVotingPower int64) *Validator {
 	// this modulo limits the ProposerPriority/VotingPower to stay in the
 	// bounds of MaxTotalVotingPower minus the already existing voting power:
-	val := NewValidator(randPubKey(), int64(tmrand.Uint64()%uint64(MaxTotalVotingPower-totalVotingPower)))
-	val.ProposerPriority = tmrand.Int64() % (MaxTotalVotingPower - totalVotingPower)
+	val := NewValidator(randPubKey(), int64(rand.Uint64()%uint64(MaxTotalVotingPower-totalVotingPower)))
+	val.ProposerPriority = rand.Int63() % (MaxTotalVotingPower - totalVotingPower)
 	return val
 }
 
@@ -882,7 +883,7 @@ func permutation(valList []testVal) []testVal {
 		return nil
 	}
 	permList := make([]testVal, len(valList))
-	perm := tmrand.Perm(len(valList))
+	perm := rand.Perm(len(valList))
 	for i, v := range perm {
 		permList[v] = valList[i]
 	}
@@ -1284,14 +1285,14 @@ func randTestVSetCfg(t *testing.T, nBase, nAddMax int) testVSetCfg {
 	const maxPower = 1000
 	var nOld, nDel, nChanged, nAdd int
 
-	nOld = int(tmrand.Uint()%uint(nBase)) + 1
+	nOld = int(uint(rand.Int())%uint(nBase)) + 1
 	if nBase-nOld > 0 {
-		nDel = int(tmrand.Uint() % uint(nBase-nOld))
+		nDel = int(uint(rand.Int()) % uint(nBase-nOld))
 	}
 	nChanged = nBase - nOld - nDel
 
 	if nAddMax > 0 {
-		nAdd = tmrand.Int()%nAddMax + 1
+		nAdd = rand.Int()%nAddMax + 1
 	}
 
 	cfg := testVSetCfg{}
@@ -1303,12 +1304,12 @@ func randTestVSetCfg(t *testing.T, nBase, nAddMax int) testVSetCfg {
 	cfg.expectedVals = make([]testVal, nBase-nDel+nAdd)
 
 	for i := 0; i < nBase; i++ {
-		cfg.startVals[i] = testVal{fmt.Sprintf("v%d", i), int64(tmrand.Uint()%maxPower + 1)}
+		cfg.startVals[i] = testVal{fmt.Sprintf("v%d", i), int64(uint(rand.Int())%maxPower + 1)}
 		if i < nOld {
 			cfg.expectedVals[i] = cfg.startVals[i]
 		}
 		if i >= nOld && i < nOld+nChanged {
-			cfg.updatedVals[i-nOld] = testVal{fmt.Sprintf("v%d", i), int64(tmrand.Uint()%maxPower + 1)}
+			cfg.updatedVals[i-nOld] = testVal{fmt.Sprintf("v%d", i), int64(uint(rand.Int())%maxPower + 1)}
 			cfg.expectedVals[i] = cfg.updatedVals[i-nOld]
 		}
 		if i >= nOld+nChanged {
@@ -1317,7 +1318,7 @@ func randTestVSetCfg(t *testing.T, nBase, nAddMax int) testVSetCfg {
 	}
 
 	for i := nBase; i < nBase+nAdd; i++ {
-		cfg.addedVals[i-nBase] = testVal{fmt.Sprintf("v%d", i), int64(tmrand.Uint()%maxPower + 1)}
+		cfg.addedVals[i-nBase] = testVal{fmt.Sprintf("v%d", i), int64(uint(rand.Int())%maxPower + 1)}
 		cfg.expectedVals[i-nDel] = cfg.addedVals[i-nBase]
 	}
 
@@ -1398,7 +1399,7 @@ func TestValSetUpdatePriorityOrderTests(t *testing.T) {
 
 func verifyValSetUpdatePriorityOrder(t *testing.T, valSet *ValidatorSet, cfg testVSetCfg, nMaxElections int32) {
 	// Run election up to nMaxElections times, sort validators by priorities
-	valSet.IncrementProposerPriority(tmrand.Int31()%nMaxElections + 1)
+	valSet.IncrementProposerPriority(rand.Int31()%nMaxElections + 1)
 
 	// apply the changes, get the updated validators, sort by priorities
 	applyChangesToValSet(t, nil, valSet, cfg.addedVals, cfg.updatedVals, cfg.deletedVals)