Merge branch 'jej-22869' into 'security'

Fix information disclosure in `Projects::BlobController#update`

It was possible to discover private project names by modifying `from_merge_request`parameter in `Projects::BlobController#update`. This fixes that.

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

https://gitlab.com/gitlab-org/gitlab-ce/issues/22869

See merge request !2023

1 files changed, 8 insertions, 12 deletions

diff --git a/app/controllers/projects/blob_controller.rb b/app/controllers/projects/blob_controller.rb
index 56ced786311..9940263ae24 100644
--- a/app/controllers/projects/blob_controller.rb
+++ b/app/controllers/projects/blob_controller.rb
@@ -13,7 +13,6 @@ class Projects::BlobController < Projects::ApplicationController
   before_action :assign_blob_vars
   before_action :commit, except: [:new, :create]
   before_action :blob, except: [:new, :create]
-  before_action :from_merge_request, only: [:edit, :update]
   before_action :require_branch_head, only: [:edit, :update]
   before_action :editor_variables, except: [:show, :preview, :diff]
   before_action :validate_diff_params, only: :diff
@@ -39,14 +38,6 @@ class Projects::BlobController < Projects::ApplicationController
 
   def update
     @path = params[:file_path] if params[:file_path].present?
-    after_edit_path =
-      if from_merge_request && @target_branch == @ref
-        diffs_namespace_project_merge_request_path(from_merge_request.target_project.namespace, from_merge_request.target_project, from_merge_request) +
-          "##{hexdigest(@path)}"
-      else
-        namespace_project_blob_path(@project.namespace, @project, File.join(@target_branch, @path))
-      end
-
     create_commit(Files::UpdateService, success_path: after_edit_path,
                                         failure_view: :edit,
                                         failure_path: namespace_project_blob_path(@project.namespace, @project, @id))
@@ -124,9 +115,14 @@ class Projects::BlobController < Projects::ApplicationController
     render_404
   end
 
-  def from_merge_request
-    # If blob edit was initiated from merge request page
-    @from_merge_request ||= MergeRequest.find_by(id: params[:from_merge_request_id])
+  def after_edit_path
+    from_merge_request = MergeRequestsFinder.new(current_user, project_id: @project.id).execute.find_by(iid: params[:from_merge_request_iid])
+    if from_merge_request && @target_branch == @ref
+      diffs_namespace_project_merge_request_path(from_merge_request.target_project.namespace, from_merge_request.target_project, from_merge_request) +
+        "##{hexdigest(@path)}"
+    else
+      namespace_project_blob_path(@project.namespace, @project, File.join(@target_branch, @path))
+    end
   end
 
   def editor_variables