Resolving suggestions after code review.

cloudflare · Jul 6, 2021 · 0e53b81 · 0e53b81
1 parent 92a0ed0
commit 0e53b81
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Showing 6 changed files with 28 additions and 33 deletions.
diff --git a/pke/kyber/internal/common/field_test.go b/pke/kyber/internal/common/field_test.go
@@ -36,29 +36,29 @@ func TestBarrettReduceFull(t *testing.T) {
 	}
 }
 
-func randSliceUint32(N uint) []uint32 {
-	bytes := make([]uint8, 4*N)
+func randSliceUint32WithMax(length uint, max uint32) []uint32 {
+	bytes := make([]uint8, 4*length)
 	n, err := rand.Read(bytes)
 	if err != nil {
 		panic(err)
 	} else if n < len(bytes) {
 		panic("short read from RNG")
 	}
-	x := make([]uint32, N)
+	x := make([]uint32, length)
 	for i := range x {
-		x[i] = binary.LittleEndian.Uint32(bytes[4*i:])
+		x[i] = binary.LittleEndian.Uint32(bytes[4*i:]) % max
 	}
 	return x
 }
 
 func TestMontReduce(t *testing.T) {
 	N := 1000
-	r := randSliceUint32(uint(N))
 	max := uint32(Q) * (1 << 16)
 	mid := int32(Q) * (1 << 15)
+	r := randSliceUint32WithMax(uint(N), max)
 
 	for i := 0; i < N; i++ {
-		x := int32(r[i]%max) - mid
+		x := int32(r[i]) - mid
 		y := montReduce(x)
 		if modQ32(x) != modQ32(int32(y)*(1<<16)) {
 			t.Fatalf("%d", x)

diff --git a/pke/kyber/internal/common/ntt_test.go b/pke/kyber/internal/common/ntt_test.go
@@ -31,18 +31,18 @@ func BenchmarkInvNTTGeneric(b *testing.B) {
 }
 
 func (p *Poly) Rand() {
-	r := randSliceUint32(uint(N))
 	max := uint32(Q)
+	r := randSliceUint32WithMax(uint(N), max)
 	for i := 0; i < N; i++ {
-		p[i] = int16(r[i] % max)
+		p[i] = int16(r[i])
 	}
 }
 
 func (p *Poly) RandAbsLeQ() {
-	r := randSliceUint32(uint(N))
 	max := 2 * uint32(Q)
+	r := randSliceUint32WithMax(uint(N), max)
 	for i := 0; i < N; i++ {
-		p[i] = int16(int32(r[i]%max) - int32(Q))
+		p[i] = int16(int32(r[i]) - int32(Q))
 	}
 }
 

diff --git a/pke/kyber/internal/common/poly_test.go b/pke/kyber/internal/common/poly_test.go
@@ -7,10 +7,10 @@ import (
 )
 
 func (p *Poly) RandAbsLe9Q() {
-	r := randSliceUint32(uint(N))
 	max := 9 * uint32(Q)
+	r := randSliceUint32WithMax(uint(N), max)
 	for i := 0; i < N; i++ {
-		p[i] = int16(int32(r[i] % max))
+		p[i] = int16(int32(r[i]))
 	}
 }
 
@@ -27,9 +27,10 @@ func TestDecompressMessage(t *testing.T) {
 	var m, m2 [PlaintextSize]byte
 	var p Poly
 	for i := 0; i < 1000; i++ {
-		_, err := rand.Read(m[:])
-		if err != nil {
+		if n, err := rand.Read(m[:]); err != nil {
 			t.Error(err)
+		} else if n != len(m) {
+			t.Fatal("short read from RNG")
 		}
 
 		p.DecompressMessage(m[:])

diff --git a/sign/dilithium/internal/common/field_test.go b/sign/dilithium/internal/common/field_test.go
@@ -4,22 +4,24 @@ import (
 	"crypto/rand"
 	"encoding/binary"
 	"flag"
+	"math"
 	"testing"
 )
 
 var runVeryLongTest = flag.Bool("very-long", false, "runs very long tests")
 
-func randSliceUint32(N uint) []uint32 {
-	bytes := make([]uint8, 4*N)
-	n, err := rand.Read(bytes)
-	if err != nil {
+func randSliceUint32(length uint) []uint32 { return randSliceUint32WithMax(length, math.MaxUint32) }
+
+func randSliceUint32WithMax(length uint, max uint32) []uint32 {
+	bytes := make([]uint8, 4*length)
+	if n, err := rand.Read(bytes); err != nil {
 		panic(err)
 	} else if n < len(bytes) {
 		panic("short read from RNG")
 	}
-	x := make([]uint32, N)
+	x := make([]uint32, length)
 	for i := range x {
-		x[i] = binary.LittleEndian.Uint32(bytes[4*i:])
+		x[i] = binary.LittleEndian.Uint32(bytes[4*i:]) % max
 	}
 	return x
 }

diff --git a/sign/dilithium/internal/common/ntt_test.go b/sign/dilithium/internal/common/ntt_test.go
@@ -3,11 +3,9 @@ package common
 import "testing"
 
 func (p *Poly) RandLe2Q() {
-	r := randSliceUint32(N)
 	max := 2 * uint32(Q)
-	for i := uint(0); i < N; i++ {
-		p[i] = r[i] % max
-	}
+	r := randSliceUint32WithMax(N, max)
+	copy(p[:], r)
 }
 
 func TestNTTAgainstGeneric(t *testing.T) {

diff --git a/sign/dilithium/internal/common/pack_test.go b/sign/dilithium/internal/common/pack_test.go
@@ -1,20 +1,14 @@
 package common
 
-import (
-	"crypto/rand"
-	"testing"
-)
+import "testing"
 
 func TestPackLe16AgainstGeneric(t *testing.T) {
 	var p Poly
 	var buf1, buf2 [PolyLe16Size]byte
-	pp := make([]uint8, 256)
 
 	for j := 0; j < 1000; j++ {
-		_, _ = rand.Read(pp)
-		for i := 0; i < 256; i++ {
-			p[i] = uint32(pp[i] & 0xF)
-		}
+		pp := randSliceUint32WithMax(N, 16)
+		copy(p[:], pp)
 		p.PackLe16(buf1[:])
 		p.packLe16Generic(buf2[:])
 		if buf1 != buf2 {