feat!: reserve the last 256 namespaces for protocol use (backport #2257)

pkg/namespace/consts.go

@@ -36,35 +36,50 @@ var (
 	// NamespaceVersionZeroPrefix is the prefix of a namespace ID for version 0.
 	NamespaceVersionZeroPrefix = bytes.Repeat([]byte{0}, NamespaceVersionZeroPrefixSize)
 
-	// TxNamespace is the namespace reserved for transaction data.
-	TxNamespace = MustNewV0([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 1})
+	// TxNamespace is the namespace reserved for ordinary Cosmos SDK transactions.
+	TxNamespace = primaryReservedNamespace(0x01)
 
 	// IntermediateStateRootsNamespace is the namespace reserved for
 	// intermediate state root data.
-	IntermediateStateRootsNamespace = MustNewV0([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 2})
+	IntermediateStateRootsNamespace = primaryReservedNamespace(0x02)
 
 	// PayForBlobNamespace is the namespace reserved for PayForBlobs transactions.
-	PayForBlobNamespace = MustNewV0([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 4})
+	PayForBlobNamespace = primaryReservedNamespace(0x04)
 
-	// ReservedPaddingNamespace is the namespace used for padding after all
-	// reserved namespaces. In practice this padding is after transactions
-	// (ordinary and PFBs) but before blobs.
-	ReservedPaddingNamespace = MustNewV0([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 255})
+	// PrimaryReservedPaddingNamespace is the namespace used for padding after all
+	// primary reserved namespaces.
+	PrimaryReservedPaddingNamespace = primaryReservedNamespace(0xFF)
 
-	// MaxReservedNamespace is lexicographically the largest namespace that is
-	// reserved for protocol use.
-	MaxReservedNamespace = MustNewV0([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 255})
+	// MaxPrimaryReservedNamespace is the highest primary reserved namespace.
+	// Namespaces lower than this are reserved for protocol use.
+	MaxPrimaryReservedNamespace = primaryReservedNamespace(0xFF)
+
+	// MinSecondaryReservedNamespace is the lowest secondary reserved namespace
+	// reserved for protocol use. Namespaces higher than this are reserved for
+	// protocol use.
+	MinSecondaryReservedNamespace = secondaryReservedNamespace(0x00)
 
 	// TailPaddingNamespace is the namespace reserved for tail padding. All data
 	// with this namespace will be ignored.
-	TailPaddingNamespace = Namespace{
-		Version: math.MaxUint8,
-		ID:      append(bytes.Repeat([]byte{0xFF}, NamespaceIDSize-1), 0xFE),
-	}
+	TailPaddingNamespace = secondaryReservedNamespace(0xFE)
 
 	// ParitySharesNamespace is the namespace reserved for erasure coded data.
-	ParitySharesNamespace = Namespace{
-		Version: math.MaxUint8,
-		ID:      bytes.Repeat([]byte{0xFF}, NamespaceIDSize),
-	}
+	ParitySharesNamespace = secondaryReservedNamespace(0xFF)
+
+	// SupportedBlobNamespaceVersions is a list of namespace versions that can be specified by a user for blobs.
+	SupportedBlobNamespaceVersions = []uint8{NamespaceVersionZero}
 )
+
+func primaryReservedNamespace(lastByte byte) Namespace {
+	return Namespace{
+		Version: NamespaceVersionZero,
+		ID:      append(bytes.Repeat([]byte{0x00}, NamespaceIDSize-1), lastByte),
+	}
+}
+
+func secondaryReservedNamespace(lastByte byte) Namespace {
+	return Namespace{
+		Version: NamespaceVersionMax,
+		ID:      append(bytes.Repeat([]byte{0xFF}, NamespaceIDSize-1), lastByte),
+	}
+}

pkg/namespace/namespace.go

@@ -12,7 +12,7 @@ type Namespace struct {
 
 // New returns a new namespace with the provided version and id.
 func New(version uint8, id []byte) (Namespace, error) {
-	err := validateVersion(version)
+	err := validateVersionSupported(version)
 	if err != nil {
 		return Namespace{}, err
 	}
@@ -83,25 +83,8 @@ func (n Namespace) Bytes() []byte {
 	return append([]byte{n.Version}, n.ID...)
 }
 
-// ValidateBlobNamespace returns an error if this namespace is not a valid blob namespace.
-func (n Namespace) ValidateBlobNamespace() error {
-	if n.IsReserved() {
-		return fmt.Errorf("invalid blob namespace: %v cannot use a reserved namespace ID, want > %v", n.Bytes(), MaxReservedNamespace.Bytes())
-	}
-
-	if n.IsParityShares() {
-		return fmt.Errorf("invalid blob namespace: %v cannot use parity shares namespace ID", n.Bytes())
-	}
-
-	if n.IsTailPadding() {
-		return fmt.Errorf("invalid blob namespace: %v cannot use tail padding namespace ID", n.Bytes())
-	}
-
-	return nil
-}
-
-// validateVersion returns an error if the version is not supported.
-func validateVersion(version uint8) error {
+// validateVersionSupported returns an error if the version is not supported.
+func validateVersionSupported(version uint8) error {
 	if version != NamespaceVersionZero && version != NamespaceVersionMax {
 		return fmt.Errorf("unsupported namespace version %v", version)
 	}
@@ -121,8 +104,17 @@ func validateID(version uint8, id []byte) error {
 	return nil
 }
 
+// IsReserved returns true if the namespace is reserved for protocol-use.
 func (n Namespace) IsReserved() bool {
-	return bytes.Compare(n.Bytes(), MaxReservedNamespace.Bytes()) < 1
+	return n.IsPrimaryReserved() || n.IsSecondaryReserved()
+}
+
+func (n Namespace) IsPrimaryReserved() bool {
+	return n.IsLessOrEqualThan(MaxPrimaryReservedNamespace)
+}
+
+func (n Namespace) IsSecondaryReserved() bool {
+	return n.IsGreaterOrEqualThan(MinSecondaryReservedNamespace)
 }
 
 func (n Namespace) IsParityShares() bool {
@@ -133,8 +125,8 @@ func (n Namespace) IsTailPadding() bool {
 	return bytes.Equal(n.Bytes(), TailPaddingNamespace.Bytes())
 }
 
-func (n Namespace) IsReservedPadding() bool {
-	return bytes.Equal(n.Bytes(), ReservedPaddingNamespace.Bytes())
+func (n Namespace) IsPrimaryReservedPadding() bool {
+	return bytes.Equal(n.Bytes(), PrimaryReservedPaddingNamespace.Bytes())
 }
 
 func (n Namespace) IsTx() bool {

pkg/namespace/namespace_test.go

@@ -2,6 +2,8 @@ package namespace
 
 import (
 	"bytes"
+	"math"
+	"reflect"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -195,3 +197,90 @@ func TestBytes(t *testing.T) {
 
 	assert.Equal(t, want, got)
 }
+
+func TestLeftPad(t *testing.T) {
+	tests := []struct {
+		input    []byte
+		size     int
+		expected []byte
+	}{
+		// input smaller than pad size
+		{[]byte{1, 2, 3}, 10, []byte{0, 0, 0, 0, 0, 0, 0, 1, 2, 3}},
+		{[]byte{1}, 5, []byte{0, 0, 0, 0, 1}},
+		{[]byte{1, 2}, 4, []byte{0, 0, 1, 2}},
+
+		// input equal to pad size
+		{[]byte{1, 2, 3}, 3, []byte{1, 2, 3}},
+		{[]byte{1, 2, 3, 4}, 4, []byte{1, 2, 3, 4}},
+
+		// input larger than pad size
+		{[]byte{1, 2, 3, 4, 5}, 4, []byte{1, 2, 3, 4, 5}},
+		{[]byte{1, 2, 3, 4, 5, 6, 7}, 3, []byte{1, 2, 3, 4, 5, 6, 7}},
+
+		// input size 0
+		{[]byte{}, 8, []byte{0, 0, 0, 0, 0, 0, 0, 0}},
+		{[]byte{}, 0, []byte{}},
+	}
+
+	for _, test := range tests {
+		result := leftPad(test.input, test.size)
+		assert.True(t, reflect.DeepEqual(result, test.expected))
+	}
+}
+
+func TestIsReserved(t *testing.T) {
+	type testCase struct {
+		ns   Namespace
+		want bool
+	}
+	testCases := []testCase{
+		{
+			ns:   MustNewV0(bytes.Repeat([]byte{1}, NamespaceVersionZeroIDSize)),
+			want: false,
+		},
+		{
+			ns:   TxNamespace,
+			want: true,
+		},
+		{
+			ns:   IntermediateStateRootsNamespace,
+			want: true,
+		},
+		{
+			ns:   PayForBlobNamespace,
+			want: true,
+		},
+		{
+			ns:   PrimaryReservedPaddingNamespace,
+			want: true,
+		},
+		{
+			ns:   MaxPrimaryReservedNamespace,
+			want: true,
+		},
+		{
+			ns:   MinSecondaryReservedNamespace,
+			want: true,
+		},
+		{
+			ns:   TailPaddingNamespace,
+			want: true,
+		},
+		{
+			ns:   ParitySharesNamespace,
+			want: true,
+		},
+		{
+			ns: Namespace{
+				Version: math.MaxUint8,
+				ID:      append(bytes.Repeat([]byte{0xFF}, NamespaceIDSize-1), 1),
+			},
+			want: true,
+		},
+	}
+
+	for _, tc := range testCases {
+		got := tc.ns.IsReserved()
+		assert.Equal(t, tc.want, got)
+	}
+}

pkg/namespace/random_blob.go

@@ -2,6 +2,7 @@ package namespace
 
 import (
 	tmrand "github.com/tendermint/tendermint/libs/rand"
+	"golang.org/x/exp/slices"
 )
 
 func RandomBlobNamespaceID() []byte {
@@ -22,11 +23,9 @@ func RandomBlobNamespaceWithPRG(prg *tmrand.Rand) Namespace {
 	for {
 		id := RandomBlobNamespaceIDWithPRG(prg)
 		namespace := MustNewV0(id)
-		err := namespace.ValidateBlobNamespace()
-		if err != nil {
-			continue
+		if isBlobNamespace(namespace) {
+			return namespace
 		}
-		return namespace
 	}
 }
 
@@ -36,3 +35,17 @@ func RandomBlobNamespaces(rand *tmrand.Rand, count int) (namespaces []Namespace)
 	}
 	return namespaces
 }
+
+// isBlobNamespace returns an true if this namespace is a valid user-specifiable
+// blob namespace.
+func isBlobNamespace(ns Namespace) bool {
+	if ns.IsReserved() {
+		return false
+	}
+
+	if !slices.Contains(SupportedBlobNamespaceVersions, ns.Version) {
+		return false
+	}
+
+	return true
+}

pkg/shares/padding.go

@@ -10,10 +10,11 @@ import (
 
 // NamespacePaddingShare returns a share that acts as padding. Namespace padding
 // shares follow a blob so that the next blob may start at an index that
-// conforms to blob share commitment rules. The ns parameter provided should
-// be the namespace of the blob that precedes this padding in the data square.
-func NamespacePaddingShare(ns appns.Namespace) (Share, error) {
-	b, err := NewBuilder(ns, appconsts.ShareVersionZero, true).Init()
+// conforms to blob share commitment rules. The ns and shareVersion parameters
+// provided should be the namespace and shareVersion of the blob that precedes
+// this padding in the data square.
+func NamespacePaddingShare(ns appns.Namespace, shareVersion uint8) (Share, error) {
+	b, err := NewBuilder(ns, shareVersion, true).Init()
 	if err != nil {
 		return Share{}, err
 	}
@@ -32,14 +33,14 @@ func NamespacePaddingShare(ns appns.Namespace) (Share, error) {
 }
 
 // NamespacePaddingShares returns n namespace padding shares.
-func NamespacePaddingShares(ns appns.Namespace, n int) ([]Share, error) {
+func NamespacePaddingShares(ns appns.Namespace, shareVersion uint8, n int) ([]Share, error) {
 	var err error
 	if n < 0 {
 		return nil, errors.New("n must be positive")
 	}
 	shares := make([]Share, n)
 	for i := 0; i < n; i++ {
-		shares[i], err = NamespacePaddingShare(ns)
+		shares[i], err = NamespacePaddingShare(ns, shareVersion)
 		if err != nil {
 			return shares, err
 		}
@@ -52,7 +53,7 @@ func NamespacePaddingShares(ns appns.Namespace, n int) ([]Share, error) {
 // first blob can start at an index that conforms to non-interactive default
 // rules.
 func ReservedPaddingShare() Share {
-	share, err := NamespacePaddingShare(appns.ReservedPaddingNamespace)
+	share, err := NamespacePaddingShare(appns.PrimaryReservedPaddingNamespace, appconsts.ShareVersionZero)
 	if err != nil {
 		panic(err)
 	}
@@ -61,7 +62,7 @@ func ReservedPaddingShare() Share {
 
 // ReservedPaddingShare returns n reserved padding shares.
 func ReservedPaddingShares(n int) []Share {
-	shares, err := NamespacePaddingShares(appns.ReservedPaddingNamespace, n)
+	shares, err := NamespacePaddingShares(appns.PrimaryReservedPaddingNamespace, appconsts.ShareVersionZero, n)
 	if err != nil {
 		panic(err)
 	}
@@ -72,7 +73,7 @@ func ReservedPaddingShares(n int) []Share {
 // square size. Tail padding shares follow the last blob share in the data
 // square.
 func TailPaddingShare() Share {
-	share, err := NamespacePaddingShare(appns.TailPaddingNamespace)
+	share, err := NamespacePaddingShare(appns.TailPaddingNamespace, appconsts.ShareVersionZero)
 	if err != nil {
 		panic(err)
 	}
@@ -81,7 +82,7 @@ func TailPaddingShare() Share {
 
 // TailPaddingShares returns n tail padding shares.
 func TailPaddingShares(n int) []Share {
-	shares, err := NamespacePaddingShares(appns.TailPaddingNamespace, n)
+	shares, err := NamespacePaddingShares(appns.TailPaddingNamespace, appconsts.ShareVersionZero, n)
 	if err != nil {
 		panic(err)
 	}

pkg/shares/padding_test.go

@@ -23,7 +23,7 @@ var nsOnePadding, _ = zeroPadIfNecessary(
 
 var reservedPadding, _ = zeroPadIfNecessary(
 	append(
-		appns.ReservedPaddingNamespace.Bytes(),
+		appns.PrimaryReservedPaddingNamespace.Bytes(),
 		[]byte{
 			1,          // info byte
 			0, 0, 0, 0, // sequence len
@@ -40,13 +40,13 @@ var tailPadding, _ = zeroPadIfNecessary(
 	), appconsts.ShareSize)
 
 func TestNamespacePaddingShare(t *testing.T) {
-	got, err := NamespacePaddingShare(ns1)
+	got, err := NamespacePaddingShare(ns1, appconsts.ShareVersionZero)
 	assert.NoError(t, err)
 	assert.Equal(t, nsOnePadding, got.ToBytes())
 }
 
 func TestNamespacePaddingShares(t *testing.T) {
-	shares, err := NamespacePaddingShares(ns1, 2)
+	shares, err := NamespacePaddingShares(ns1, appconsts.ShareVersionZero, 2)
 	assert.NoError(t, err)
 	for _, share := range shares {
 		assert.Equal(t, nsOnePadding, share.ToBytes())

pkg/shares/parse_test.go

@@ -41,7 +41,7 @@ func TestParseShares(t *testing.T) {
 	// because it takes more than one share to store a sequence of 1000 bytes
 	tooLargeSequenceLen := generateRawShare(t, ns1, true, uint32(1000))
 
-	ns1Padding, err := NamespacePaddingShare(ns1)
+	ns1Padding, err := NamespacePaddingShare(ns1, appconsts.ShareVersionZero)
 	require.NoError(t, err)
 
 	type testCase struct {
@@ -162,11 +162,11 @@ func TestParseShares(t *testing.T) {
 			ignorePadding: false,
 			want: []ShareSequence{
 				{
-					Namespace: appns.ReservedPaddingNamespace,
+					Namespace: appns.PrimaryReservedPaddingNamespace,
 					Shares:    []Share{ReservedPaddingShare()},
 				},
 				{
-					Namespace: appns.ReservedPaddingNamespace,
+					Namespace: appns.PrimaryReservedPaddingNamespace,
 					Shares:    []Share{ReservedPaddingShare()},
 				},
 			},