Disallow sharing the shares directory

changelog/unreleased/shares-fix.md

@@ -0,0 +1,7 @@
+Bugfix: Disallow sharing the shares directory
+
+Previously, it was possible to create public links for and share the shares
+directory itself. However, when the recipient tried to accept the share, it
+failed. This PR prevents the creation of such shares in the first place.
+
+https://github.com/cs3org/reva/pull/1051

internal/grpc/services/gateway/publicshareprovider.go

@@ -29,6 +29,10 @@ import (
 )
 
 func (s *svc) CreatePublicShare(ctx context.Context, req *link.CreatePublicShareRequest) (*link.CreatePublicShareResponse, error) {
+	if s.isSharedFolder(ctx, req.ResourceInfo.GetPath()) {
+		return nil, errors.New("gateway: can't create a public share of the share folder itself")
+	}
+
 	log := appctx.GetLogger(ctx)
 	log.Info().Msg("create public share")
 

internal/grpc/services/gateway/storageprovider.go

@@ -941,8 +941,26 @@ func (s *svc) Stat(ctx context.Context, req *provider.StatRequest) (*provider.St
 				Path: target,
 			},
 		}
+
 		req.Ref = ref
-		return s.stat(ctx, req)
+		res, err := s.stat(ctx, req)
+		if err != nil {
+			return &provider.StatResponse{
+				Status: status.NewInternal(ctx, err, "gateway: error stating"),
+			}, nil
+		}
+		if res.Status.Code != rpc.Code_CODE_OK {
+			err := status.NewErrorFromCode(res.Status.Code, "gateway")
+			log.Err(err).Msg("gateway: error stating")
+			return &provider.StatResponse{
+				Status: status.NewInternal(ctx, err, "gateway: error stating"),
+			}, nil
+		}
+
+		// we need to make sure we don't expose the reference target in the resource
+		// information.
+		res.Info.Path = p
+		return res, nil
 	}
 
 	panic("gateway: stating an unknown path:" + p)

internal/grpc/services/gateway/usershareprovider.go

@@ -35,6 +35,11 @@ import (
 
 // TODO(labkode): add multi-phase commit logic when commit share or commit ref is enabled.
 func (s *svc) CreateShare(ctx context.Context, req *collaboration.CreateShareRequest) (*collaboration.CreateShareResponse, error) {
+
+	if s.isSharedFolder(ctx, req.ResourceInfo.GetPath()) {
+		return nil, errors.New("gateway: can't share the share folder itself")
+	}
+
 	c, err := pool.GetUserShareProviderClient(s.c.UserShareProviderEndpoint)
 	if err != nil {
 		return &collaboration.CreateShareResponse{