Better metainfo Create/Commit request validation (#2088)

satellite/metainfo/metainfo.go

@@ -4,7 +4,6 @@
 package metainfo
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"strconv"
@@ -18,7 +17,6 @@ import (
 	monkit "gopkg.in/spacemonkeygo/monkit.v2"
 
 	"storj.io/storj/pkg/accounting"
-	"storj.io/storj/pkg/auth"
 	"storj.io/storj/pkg/eestream"
 	"storj.io/storj/pkg/identity"
 	"storj.io/storj/pkg/macaroon"
@@ -60,6 +58,7 @@ type Endpoint struct {
 	projectUsage   *accounting.ProjectUsage
 	containment    Containment
 	apiKeys        APIKeys
+	createRequests *createRequests
 }
 
 // NewEndpoint creates new metainfo endpoint instance
@@ -74,42 +73,13 @@ func NewEndpoint(log *zap.Logger, metainfo *Service, orders *orders.Service, cac
 		containment:    containment,
 		apiKeys:        apiKeys,
 		projectUsage:   projectUsage,
+		createRequests: newCreateRequests(),
 	}
 }
 
 // Close closes resources
 func (endpoint *Endpoint) Close() error { return nil }
 
-func (endpoint *Endpoint) validateAuth(ctx context.Context, action macaroon.Action) (_ *console.APIKeyInfo, err error) {
-	defer mon.Task()(&ctx)(&err)
-	keyData, ok := auth.GetAPIKey(ctx)
-	if !ok {
-		endpoint.log.Error("unauthorized request", zap.Error(status.Errorf(codes.Unauthenticated, "Invalid API credential")))
-		return nil, status.Errorf(codes.Unauthenticated, "Invalid API credential")
-	}
-
-	key, err := macaroon.ParseAPIKey(string(keyData))
-	if err != nil {
-		endpoint.log.Error("unauthorized request", zap.Error(status.Errorf(codes.Unauthenticated, "Invalid API credential")))
-		return nil, status.Errorf(codes.Unauthenticated, "Invalid API credential")
-	}
-
-	keyInfo, err := endpoint.apiKeys.GetByHead(ctx, key.Head())
-	if err != nil {
-		endpoint.log.Error("unauthorized request", zap.Error(status.Errorf(codes.Unauthenticated, err.Error())))
-		return nil, status.Errorf(codes.Unauthenticated, "Invalid API credential")
-	}
-
-	// Revocations are currently handled by just deleting the key.
-	err = key.Check(ctx, keyInfo.Secret, action, nil)
-	if err != nil {
-		endpoint.log.Error("unauthorized request", zap.Error(status.Errorf(codes.Unauthenticated, err.Error())))
-		return nil, status.Errorf(codes.Unauthenticated, "Invalid API credential")
-	}
-
-	return keyInfo, nil
-}
-
 // SegmentInfo returns segment metadata info
 func (endpoint *Endpoint) SegmentInfo(ctx context.Context, req *pb.SegmentInfoRequest) (resp *pb.SegmentInfoResponse, err error) {
 	defer mon.Task()(&ctx)(&err)
@@ -209,6 +179,13 @@ func (endpoint *Endpoint) CreateSegment(ctx context.Context, req *pb.SegmentWrit
 		return nil, Error.Wrap(err)
 	}
 
+	if len(addressedLimits) > 0 {
+		endpoint.createRequests.Put(addressedLimits[0].Limit.SerialNumber, &createRequest{
+			Expiration: req.Expiration,
+			Redundancy: req.Redundancy,
+		})
+	}
+
 	return &pb.SegmentWriteResponse{AddressedLimits: addressedLimits, RootPieceId: rootPieceID}, nil
 }
 
@@ -247,7 +224,7 @@ func (endpoint *Endpoint) CommitSegment(ctx context.Context, req *pb.SegmentComm
 		return nil, status.Errorf(codes.InvalidArgument, err.Error())
 	}
 
-	err = endpoint.validateCommit(ctx, req)
+	err = endpoint.validateCommitSegment(ctx, req)
 	if err != nil {
 		return nil, status.Errorf(codes.Internal, err.Error())
 	}
@@ -288,6 +265,10 @@ func (endpoint *Endpoint) CommitSegment(ctx context.Context, req *pb.SegmentComm
 		return nil, status.Errorf(codes.Internal, err.Error())
 	}
 
+	if len(req.OriginalLimits) > 0 {
+		endpoint.createRequests.Remove(req.OriginalLimits[0].SerialNumber)
+	}
+
 	return &pb.SegmentCommitResponse{Pointer: pointer}, nil
 }
 
@@ -503,78 +484,6 @@ func (endpoint *Endpoint) filterValidPieces(ctx context.Context, pointer *pb.Poi
 	return nil
 }
 
-func (endpoint *Endpoint) validateBucket(ctx context.Context, bucket []byte) (err error) {
-	defer mon.Task()(&ctx)(&err)
-	if len(bucket) == 0 {
-		return errs.New("bucket not specified")
-	}
-	if bytes.ContainsAny(bucket, "/") {
-		return errs.New("bucket should not contain slash")
-	}
-	return nil
-}
-
-func (endpoint *Endpoint) validateCommit(ctx context.Context, req *pb.SegmentCommitRequest) (err error) {
-	defer mon.Task()(&ctx)(&err)
-	err = endpoint.validatePointer(ctx, req.Pointer)
-	if err != nil {
-		return err
-	}
-
-	if req.Pointer.Type == pb.Pointer_REMOTE {
-		remote := req.Pointer.Remote
-
-		if len(req.OriginalLimits) == 0 {
-			return Error.New("no order limits")
-		}
-		if int32(len(req.OriginalLimits)) != remote.Redundancy.Total {
-			return Error.New("invalid no order limit for piece")
-		}
-
-		for _, piece := range remote.RemotePieces {
-			limit := req.OriginalLimits[piece.PieceNum]
-
-			err := endpoint.orders.VerifyOrderLimitSignature(ctx, limit)
-			if err != nil {
-				return err
-			}
-
-			if limit == nil {
-				return Error.New("invalid no order limit for piece")
-			}
-			derivedPieceID := remote.RootPieceId.Derive(piece.NodeId)
-			if limit.PieceId.IsZero() || limit.PieceId != derivedPieceID {
-				return Error.New("invalid order limit piece id")
-			}
-			if bytes.Compare(piece.NodeId.Bytes(), limit.StorageNodeId.Bytes()) != 0 {
-				return Error.New("piece NodeID != order limit NodeID")
-			}
-		}
-	}
-	return nil
-}
-
-func (endpoint *Endpoint) validatePointer(ctx context.Context, pointer *pb.Pointer) (err error) {
-	defer mon.Task()(&ctx)(&err)
-	if pointer == nil {
-		return Error.New("no pointer specified")
-	}
-
-	// TODO does it all?
-	if pointer.Type == pb.Pointer_REMOTE {
-		if pointer.Remote == nil {
-			return Error.New("no remote segment specified")
-		}
-		if pointer.Remote.RemotePieces == nil {
-			return Error.New("no remote segment pieces specified")
-		}
-		if pointer.Remote.Redundancy == nil {
-			return Error.New("no redundancy scheme specified")
-		}
-	}
-	return nil
-}
-
 // CreatePath will create a Segment path
 func CreatePath(ctx context.Context, projectID uuid.UUID, segmentIndex int64, bucket, path []byte) (_ storj.Path, err error) {
 	defer mon.Task()(&ctx)(&err)
@@ -597,12 +506,3 @@ func CreatePath(ctx context.Context, projectID uuid.UUID, segmentIndex int64, bu
 	}
 	return storj.JoinPaths(entries...), nil
 }
-
-func (endpoint *Endpoint) validateRedundancy(ctx context.Context, redundancy *pb.RedundancyScheme) (err error) {
-	defer mon.Task()(&ctx)(&err)
-	// TODO more validation, use validation from eestream.NewRedundancyStrategy
-	if redundancy.ErasureShareSize <= 0 {
-		return Error.New("erasure share size cannot be less than 0")
-	}
-	return nil
-}

satellite/metainfo/metainfo_test.go

@@ -9,19 +9,21 @@ import (
 	"testing"
 	"time"
 
-	"google.golang.org/grpc/codes"
+	"github.com/golang/protobuf/ptypes"
-	"google.golang.org/grpc/status"
-
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/zeebo/errs"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 
+	"storj.io/storj/internal/memory"
 	"storj.io/storj/internal/testcontext"
 	"storj.io/storj/internal/testplanet"
 	"storj.io/storj/pkg/macaroon"
 	"storj.io/storj/pkg/pb"
 	"storj.io/storj/pkg/storj"
 	"storj.io/storj/satellite/console"
+	"storj.io/storj/uplink/metainfo"
 )
 
 // mockAPIKeys is mock for api keys store of pointerdb
@@ -298,7 +300,8 @@ func TestCommitSegment(t *testing.T) {
 				Total:            6,
 				ErasureShareSize: 10,
 			}
-			addresedLimits, rootPieceID, err := metainfo.CreateSegment(ctx, "bucket", "path", -1, redundancy, 1000, time.Now())
+			expirationDate := time.Now()
+			addresedLimits, rootPieceID, err := metainfo.CreateSegment(ctx, "bucket", "path", -1, redundancy, 1000, expirationDate)
 			require.NoError(t, err)
 
 			// create number of pieces below repair threshold
@@ -310,6 +313,10 @@ func TestCommitSegment(t *testing.T) {
 					NodeId:   limit.Limit.StorageNodeId,
 				}
 			}
+
+			expirationDateProto, err := ptypes.TimestampProto(expirationDate)
+			require.NoError(t, err)
+
 			pointer := &pb.Pointer{
 				Type: pb.Pointer_REMOTE,
 				Remote: &pb.RemoteSegment{
@@ -317,6 +324,7 @@ func TestCommitSegment(t *testing.T) {
 					Redundancy:   redundancy,
 					RemotePieces: pieces,
 				},
+				ExpirationDate: expirationDateProto,
 			}
 
 			limits := make([]*pb.OrderLimit2, len(addresedLimits))
@@ -329,3 +337,148 @@ func TestCommitSegment(t *testing.T) {
 		}
 	})
 }
+
+func TestDoubleCommitSegment(t *testing.T) {
+	testplanet.Run(t, testplanet.Config{
+		SatelliteCount: 1, StorageNodeCount: 6, UplinkCount: 1,
+	}, func(t *testing.T, ctx *testcontext.Context, planet *testplanet.Planet) {
+		apiKey := planet.Uplinks[0].APIKey[planet.Satellites[0].ID()]
+
+		metainfo, err := planet.Uplinks[0].DialMetainfo(ctx, planet.Satellites[0], apiKey)
+		require.NoError(t, err)
+
+		pointer, limits := runCreateSegment(ctx, t, metainfo)
+
+		_, err = metainfo.CommitSegment(ctx, "myBucketName", "file/path", -1, pointer, limits)
+		require.NoError(t, err)
+
+		_, err = metainfo.CommitSegment(ctx, "myBucketName", "file/path", -1, pointer, limits)
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "missing create request or request expired")
+	})
+}
+
+func TestCommitSegmentPointer(t *testing.T) {
+	// all tests needs to generate error
+	tests := []struct {
+		// defines how modify pointer before CommitSegment
+		Modify       func(pointer *pb.Pointer)
+		ErrorMessage string
+	}{
+		{
+			Modify: func(pointer *pb.Pointer) {
+				pointer.ExpirationDate.Seconds += 100
+			},
+			ErrorMessage: "pointer expiration date does not match requested one",
+		},
+		{
+			Modify: func(pointer *pb.Pointer) {
+				pointer.Remote.Redundancy.MinReq += 100
+			},
+			ErrorMessage: "pointer redundancy scheme date does not match requested one",
+		},
+		{
+			Modify: func(pointer *pb.Pointer) {
+				pointer.Remote.Redundancy.RepairThreshold += 100
+			},
+			ErrorMessage: "pointer redundancy scheme date does not match requested one",
+		},
+		{
+			Modify: func(pointer *pb.Pointer) {
+				pointer.Remote.Redundancy.SuccessThreshold += 100
+			},
+			ErrorMessage: "pointer redundancy scheme date does not match requested one",
+		},
+		{
+			Modify: func(pointer *pb.Pointer) {
+				pointer.Remote.Redundancy.Total += 100
+			},
+			// this error is triggered earlier then Create/Commit RS comparison
+			ErrorMessage: "invalid no order limit for piece",
+		},
+		{
+			Modify: func(pointer *pb.Pointer) {
+				pointer.Remote.Redundancy.ErasureShareSize += 100
+			},
+			ErrorMessage: "pointer redundancy scheme date does not match requested one",
+		},
+		{
+			Modify: func(pointer *pb.Pointer) {
+				pointer.Remote.Redundancy.Type = 100
+			},
+			ErrorMessage: "pointer redundancy scheme date does not match requested one",
+		},
+		{
+			Modify: func(pointer *pb.Pointer) {
+				pointer.Type = pb.Pointer_INLINE
+			},
+			ErrorMessage: "pointer type is INLINE but remote segment is set",
+		},
+	}
+
+	testplanet.Run(t, testplanet.Config{
+		SatelliteCount: 1, StorageNodeCount: 6, UplinkCount: 1,
+	}, func(t *testing.T, ctx *testcontext.Context, planet *testplanet.Planet) {
+		apiKey := planet.Uplinks[0].APIKey[planet.Satellites[0].ID()]
+
+		metainfo, err := planet.Uplinks[0].DialMetainfo(ctx, planet.Satellites[0], apiKey)
+		require.NoError(t, err)
+
+		for _, test := range tests {
+			pointer, limits := runCreateSegment(ctx, t, metainfo)
+			test.Modify(pointer)
+
+			_, err = metainfo.CommitSegment(ctx, "myBucketName", "file/path", -1, pointer, limits)
+			require.Error(t, err)
+			require.Contains(t, err.Error(), test.ErrorMessage)
+		}
+	})
+}
+
+func runCreateSegment(ctx context.Context, t *testing.T, metainfo metainfo.Client) (*pb.Pointer, []*pb.OrderLimit2) {
+	pointer := createTestPointer(t)
+	expirationDate, err := ptypes.Timestamp(pointer.ExpirationDate)
+	require.NoError(t, err)
+
+	addressedLimits, rootPieceID, err := metainfo.CreateSegment(ctx, "myBucketName", "file/path", -1, pointer.Remote.Redundancy, memory.MiB.Int64(), expirationDate)
+	require.NoError(t, err)
+
+	pointer.Remote.RootPieceId = rootPieceID
+	pointer.Remote.RemotePieces[0].NodeId = addressedLimits[0].Limit.StorageNodeId
+	pointer.Remote.RemotePieces[1].NodeId = addressedLimits[1].Limit.StorageNodeId
+
+	limits := make([]*pb.OrderLimit2, len(addressedLimits))
+	for i, addressedLimit := range addressedLimits {
+		limits[i] = addressedLimit.Limit
+	}
+
+	return pointer, limits
+}
+
+func createTestPointer(t *testing.T) *pb.Pointer {
+	rs := &pb.RedundancyScheme{
+		MinReq:           1,
+		RepairThreshold:  1,
+		SuccessThreshold: 3,
+		Total:            4,
+		ErasureShareSize: 1024,
+		Type:             pb.RedundancyScheme_RS,
+	}
+
+	pointer := &pb.Pointer{
+		Type: pb.Pointer_REMOTE,
+		Remote: &pb.RemoteSegment{
+			Redundancy: rs,
+			RemotePieces: []*pb.RemotePiece{
+				&pb.RemotePiece{
+					PieceNum: 0,
+				},
+				&pb.RemotePiece{
+					PieceNum: 1,
+				},
+			},
+		},
+		ExpirationDate: ptypes.TimestampNow(),
+	}
+	return pointer
+}

satellite/metainfo/validation.go

@@ -0,0 +1,268 @@
+// Copyright (C) 2019 Storj Labs, Inc.
+// See LICENSE for copying information.
+
+package metainfo
+
+import (
+	"bytes"
+	"context"
+	"sync"
+	"time"
+
+	"github.com/gogo/protobuf/proto"
+	"github.com/golang/protobuf/ptypes/timestamp"
+	"github.com/zeebo/errs"
+	"go.uber.org/zap"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	"storj.io/storj/pkg/auth"
+	"storj.io/storj/pkg/macaroon"
+	"storj.io/storj/pkg/pb"
+	"storj.io/storj/pkg/storj"
+	"storj.io/storj/satellite/console"
+)
+
+const requestTTL = time.Hour * 4
+
+// TTLItem keeps association between serial number and ttl
+type TTLItem struct {
+	serialNumber storj.SerialNumber
+	ttl          time.Time
+}
+
+type createRequest struct {
+	Expiration *timestamp.Timestamp
+	Redundancy *pb.RedundancyScheme
+
+	ttl time.Time
+}
+
+type createRequests struct {
+	mu sync.RWMutex
+	// orders limit serial number used because with CreateSegment we don't have path yet
+	entries map[storj.SerialNumber]*createRequest
+
+	muTTL      sync.Mutex
+	entriesTTL []*TTLItem
+}
+
+func newCreateRequests() *createRequests {
+	return &createRequests{
+		entries:    make(map[storj.SerialNumber]*createRequest),
+		entriesTTL: make([]*TTLItem, 0),
+	}
+}
+
+func (requests *createRequests) Put(serialNumber storj.SerialNumber, createRequest *createRequest) {
+	ttl := time.Now().Add(requestTTL)
+
+	go func() {
+		requests.muTTL.Lock()
+		requests.entriesTTL = append(requests.entriesTTL, &TTLItem{
+			serialNumber: serialNumber,
+			ttl:          ttl,
+		})
+		requests.muTTL.Unlock()
+	}()
+
+	createRequest.ttl = ttl
+	requests.mu.Lock()
+	requests.entries[serialNumber] = createRequest
+	requests.mu.Unlock()
+
+	go requests.cleanup()
+}
+
+func (requests *createRequests) Load(serialNumber storj.SerialNumber) (*createRequest, bool) {
+	requests.mu.RLock()
+	request, found := requests.entries[serialNumber]
+	if request != nil && request.ttl.Before(time.Now()) {
+		request = nil
+		found = false
+	}
+	requests.mu.RUnlock()
+
+	return request, found
+}
+
+func (requests *createRequests) Remove(serialNumber storj.SerialNumber) {
+	requests.mu.Lock()
+	delete(requests.entries, serialNumber)
+	requests.mu.Unlock()
+}
+
+func (requests *createRequests) cleanup() {
+	requests.muTTL.Lock()
+	now := time.Now()
+	remove := make([]storj.SerialNumber, 0)
+	newStart := 0
+	for i, item := range requests.entriesTTL {
+		if item.ttl.Before(now) {
+			remove = append(remove, item.serialNumber)
+			newStart = i + 1
+		} else {
+			break
+		}
+	}
+	requests.entriesTTL = requests.entriesTTL[newStart:]
+	requests.muTTL.Unlock()
+
+	for _, serialNumber := range remove {
+		requests.Remove(serialNumber)
+	}
+}
+
+func (endpoint *Endpoint) validateAuth(ctx context.Context, action macaroon.Action) (_ *console.APIKeyInfo, err error) {
+	defer mon.Task()(&ctx)(&err)
+	keyData, ok := auth.GetAPIKey(ctx)
+	if !ok {
+		endpoint.log.Error("unauthorized request", zap.Error(status.Errorf(codes.Unauthenticated, "Invalid API credential")))
+		return nil, status.Errorf(codes.Unauthenticated, "Invalid API credential")
+	}
+
+	key, err := macaroon.ParseAPIKey(string(keyData))
+	if err != nil {
+		endpoint.log.Error("unauthorized request", zap.Error(status.Errorf(codes.Unauthenticated, "Invalid API credential")))
+		return nil, status.Errorf(codes.Unauthenticated, "Invalid API credential")
+	}
+
+	keyInfo, err := endpoint.apiKeys.GetByHead(ctx, key.Head())
+	if err != nil {
+		endpoint.log.Error("unauthorized request", zap.Error(status.Errorf(codes.Unauthenticated, err.Error())))
+		return nil, status.Errorf(codes.Unauthenticated, "Invalid API credential")
+	}
+
+	// Revocations are currently handled by just deleting the key.
+	err = key.Check(ctx, keyInfo.Secret, action, nil)
+	if err != nil {
+		endpoint.log.Error("unauthorized request", zap.Error(status.Errorf(codes.Unauthenticated, err.Error())))
+		return nil, status.Errorf(codes.Unauthenticated, "Invalid API credential")
+	}
+
+	return keyInfo, nil
+}
+
+func (endpoint *Endpoint) validateCreateSegment(ctx context.Context, req *pb.SegmentWriteRequest) (err error) {
+	defer mon.Task()(&ctx)(&err)
+
+	err = endpoint.validateBucket(ctx, req.Bucket)
+	if err != nil {
+		return err
+	}
+
+	err = endpoint.validateRedundancy(ctx, req.Redundancy)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (endpoint *Endpoint) validateCommitSegment(ctx context.Context, req *pb.SegmentCommitRequest) (err error) {
+	defer mon.Task()(&ctx)(&err)
+
+	err = endpoint.validateBucket(ctx, req.Bucket)
+	if err != nil {
+		return err
+	}
+
+	err = endpoint.validatePointer(ctx, req.Pointer)
+	if err != nil {
+		return err
+	}
+
+	if req.Pointer.Type == pb.Pointer_REMOTE {
+		remote := req.Pointer.Remote
+
+		if len(req.OriginalLimits) == 0 {
+			return Error.New("no order limits")
+		}
+		if int32(len(req.OriginalLimits)) != remote.Redundancy.Total {
+			return Error.New("invalid no order limit for piece")
+		}
+
+		for _, piece := range remote.RemotePieces {
+			limit := req.OriginalLimits[piece.PieceNum]
+
+			err := endpoint.orders.VerifyOrderLimitSignature(ctx, limit)
+			if err != nil {
+				return err
+			}
+
+			if limit == nil {
+				return Error.New("invalid no order limit for piece")
+			}
+			derivedPieceID := remote.RootPieceId.Derive(piece.NodeId)
+			if limit.PieceId.IsZero() || limit.PieceId != derivedPieceID {
+				return Error.New("invalid order limit piece id")
+			}
+			if bytes.Compare(piece.NodeId.Bytes(), limit.StorageNodeId.Bytes()) != 0 {
+				return Error.New("piece NodeID != order limit NodeID")
+			}
+		}
+	}
+
+	if len(req.OriginalLimits) > 0 {
+		createRequest, found := endpoint.createRequests.Load(req.OriginalLimits[0].SerialNumber)
+
+		switch {
+		case !found:
+			return Error.New("missing create request or request expired")
+		case !proto.Equal(createRequest.Expiration, req.Pointer.ExpirationDate):
+			return Error.New("pointer expiration date does not match requested one")
+		case !proto.Equal(createRequest.Redundancy, req.Pointer.Remote.Redundancy):
+			return Error.New("pointer redundancy scheme date does not match requested one")
+		}
+	}
+
+	return nil
+}
+
+func (endpoint *Endpoint) validateBucket(ctx context.Context, bucket []byte) (err error) {
+	defer mon.Task()(&ctx)(&err)
+
+	if len(bucket) == 0 {
+		return errs.New("bucket not specified")
+	}
+	if bytes.ContainsAny(bucket, "/") {
+		return errs.New("bucket should not contain slash")
+	}
+	return nil
+}
+
+func (endpoint *Endpoint) validatePointer(ctx context.Context, pointer *pb.Pointer) (err error) {
+	defer mon.Task()(&ctx)(&err)
+
+	if pointer == nil {
+		return Error.New("no pointer specified")
+	}
+
+	if pointer.Type == pb.Pointer_INLINE && pointer.Remote != nil {
+		return Error.New("pointer type is INLINE but remote segment is set")
+	}
+
+	// TODO does it all?
+	if pointer.Type == pb.Pointer_REMOTE {
+		if pointer.Remote == nil {
+			return Error.New("no remote segment specified")
+		}
+		if pointer.Remote.RemotePieces == nil {
+			return Error.New("no remote segment pieces specified")
+		}
+		if pointer.Remote.Redundancy == nil {
+			return Error.New("no redundancy scheme specified")
+		}
+	}
+	return nil
+}
+
+func (endpoint *Endpoint) validateRedundancy(ctx context.Context, redundancy *pb.RedundancyScheme) (err error) {
+	defer mon.Task()(&ctx)(&err)
+
+	// TODO more validation, use validation from eestream.NewRedundancyStrategy
+	if redundancy.ErasureShareSize <= 0 {
+		return Error.New("erasure share size cannot be less than 0")
+	}
+	return nil
+}