Use strong parameters for CommitsController

Sentry error:
https://sentry.gitlab.net/gitlab/gitlabcom/issues/3161031

Changelog: fixed

app/controllers/projects/commits_controller.rb

@@ -67,11 +67,11 @@ class Projects::CommitsController < Projects::ApplicationController
   def set_commits
     render_404 unless @path.empty? || request.format == :atom || @repository.blob_at(@commit.id, @path) || @repository.tree(@commit.id, @path).entries.present?
 
-    limit = params[:limit].to_i
+    limit = permitted_params[:limit].to_i
     @limit = limit > 0 ? limit : COMMITS_DEFAULT_LIMIT # limit can only ever be a positive number
-    @offset = (params[:offset] || 0).to_i
-    search = params[:search]
-    author = params[:author]
+    @offset = (permitted_params[:offset] || 0).to_i
+    search = permitted_params[:search]
+    author = permitted_params[:author]
 
     @commits =
       if search.present?
@@ -87,4 +87,8 @@ class Projects::CommitsController < Projects::ApplicationController
     @commits = @commits.with_latest_pipeline(@ref)
     @commits = set_commits_for_rendering(@commits)
   end
+
+  def permitted_params
+    params.permit(:limit, :offset, :search, :author)
+  end
 end

spec/controllers/projects/commits_controller_spec.rb

@@ -88,6 +88,26 @@ RSpec.describe Projects::CommitsController do
 
           expect(response).to be_successful
         end
+
+        context 'when limit is a hash' do
+          it 'uses the default limit' do
+            expect_any_instance_of(Repository).to receive(:commits).with(
+              "master",
+              path: "README.md",
+              limit: described_class::COMMITS_DEFAULT_LIMIT,
+              offset: 0
+            ).and_call_original
+
+            get(:show, params: {
+              namespace_id: project.namespace,
+              project_id: project,
+              id: id,
+              limit: { 'broken' => 'value' }
+            })
+
+            expect(response).to be_successful
+          end
+        end
       end
 
       context "when the ref name ends in .atom" do