s3ng fix missing blob error message

changelog/unreleased/s3ng-download-validation.md

@@ -0,0 +1,6 @@
+Bugfix: validate s3ng downloads
+
+The s3ng download func now returns an error in cases where the requested node blob is unknown
+or the blob size does not match the node meta blob size.
+
+https://github.com/cs3org/reva/pull/3341

internal/http/services/owncloud/ocdav/get.go

@@ -72,6 +72,25 @@ func (s *svc) handleGet(ctx context.Context, w http.ResponseWriter, r *http.Requ
 		return
 	}
 
+	sReq := &provider.StatRequest{
+		Ref: ref,
+	}
+	sRes, err := client.Stat(ctx, sReq)
+	if err != nil {
+		log.Error().Err(err).Msg("error stat resource")
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	} else if sRes.Status.Code != rpc.Code_CODE_OK {
+		errors.HandleErrorStatus(&log, w, sRes.Status)
+		return
+	}
+
+	if sRes.Info.Type != provider.ResourceType_RESOURCE_TYPE_FILE {
+		w.Header().Set("Content-Length", "0")
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+
 	dReq := &provider.InitiateFileDownloadRequest{Ref: ref}
 	dRes, err := client.InitiateFileDownload(ctx, dReq)
 	if err != nil {

pkg/rhttp/datatx/utils/download/download.go

@@ -206,7 +206,7 @@ func GetOrHeadFile(w http.ResponseWriter, r *http.Request, fs storage.FS, spaceI
 		var c int64
 		c, err = io.CopyN(w, sendContent, sendSize)
 		if err != nil {
-			sublog.Error().Err(err).Msg("error copying data to response")
+			sublog.Error().Err(err).Interface("resourceid", md.Id).Msg("error copying data to response")
 			return
 		}
 		if c != sendSize {

pkg/storage/fs/s3ng/blobstore/blobstore.go

@@ -20,6 +20,7 @@ package blobstore
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"net/url"
 	"os"
@@ -87,6 +88,16 @@ func (bs *Blobstore) Download(node *node.Node) (io.ReadCloser, error) {
 	if err != nil {
 		return nil, errors.Wrapf(err, "could not download object '%s' from bucket '%s'", bs.path(node), bs.bucket)
 	}
+
+	stat, err := reader.Stat()
+	if err != nil {
+		return nil, errors.Wrapf(err, "blob path: %s", bs.path(node))
+	}
+
+	if node.Blobsize != stat.Size {
+		return nil, fmt.Errorf("blob has unexpected size. %d bytes expected, got %d bytes", node.Blobsize, stat.Size)
+	}
+
 	return reader, nil
 }