Commit 067dc654 authored by Nick Thomas's avatar Nick Thomas

Validate bundle files before unpacking them

parent b2e807e6
---
title: Validate bundle files before unpacking them
merge_request:
author:
type: security
# frozen_string_literal: true
module Gitlab
module Git
class BundleFile
# All git bundle files start with this string
#
# https://github.com/git/git/blob/v2.20.1/bundle.c#L15
MAGIC = "# v2 git bundle\n"
InvalidBundleError = Class.new(StandardError)
attr_reader :filename
def self.check!(filename)
new(filename).check!
end
def initialize(filename)
@filename = filename
end
def check!
data = File.open(filename, 'r') { |f| f.read(MAGIC.size) }
raise InvalidBundleError, 'Invalid bundle file' unless data == MAGIC
end
end
end
end
......@@ -789,6 +789,11 @@ module Gitlab
end
def create_from_bundle(bundle_path)
# It's important to check that the linked-to file is actually a valid
# .bundle file as it is passed to `git clone`, which may otherwise
# interpret it as a pointer to another repository
::Gitlab::Git::BundleFile.check!(bundle_path)
gitaly_repository_client.create_from_bundle(bundle_path)
end
......
require 'spec_helper'
describe Gitlab::Git::BundleFile do
describe '.check!' do
let(:valid_bundle) { Tempfile.new }
let(:valid_bundle_path) { valid_bundle.path }
let(:invalid_bundle_path) { Rails.root.join('spec/fixtures/malicious.bundle') }
after do
valid_bundle.close!
end
it 'returns nil for a valid bundle' do
valid_bundle.write("# v2 git bundle\nfoo bar baz\n")
valid_bundle.close
expect(described_class.check!(valid_bundle_path)).to be_nil
end
it 'raises an exception for an invalid bundle' do
expect do
described_class.check!(invalid_bundle_path)
end.to raise_error(described_class::InvalidBundleError)
end
end
end
......@@ -1753,22 +1753,23 @@ describe Gitlab::Git::Repository, :seed_helper do
end
describe '#create_from_bundle' do
let(:bundle_path) { File.join(Dir.tmpdir, "repo-#{SecureRandom.hex}.bundle") }
let(:valid_bundle_path) { File.join(Dir.tmpdir, "repo-#{SecureRandom.hex}.bundle") }
let(:malicious_bundle_path) { Rails.root.join('spec/fixtures/malicious.bundle') }
let(:project) { create(:project) }
let(:imported_repo) { project.repository.raw }
before do
expect(repository.bundle_to_disk(bundle_path)).to be_truthy
expect(repository.bundle_to_disk(valid_bundle_path)).to be_truthy
end
after do
FileUtils.rm_rf(bundle_path)
FileUtils.rm_rf(valid_bundle_path)
end
it 'creates a repo from a bundle file' do
expect(imported_repo).not_to exist
result = imported_repo.create_from_bundle(bundle_path)
result = imported_repo.create_from_bundle(valid_bundle_path)
expect(result).to be_truthy
expect(imported_repo).to exist
......@@ -1776,11 +1777,17 @@ describe Gitlab::Git::Repository, :seed_helper do
end
it 'creates a symlink to the global hooks dir' do
imported_repo.create_from_bundle(bundle_path)
imported_repo.create_from_bundle(valid_bundle_path)
hooks_path = Gitlab::GitalyClient::StorageSettings.allow_disk_access { File.join(imported_repo.path, 'hooks') }
expect(File.readlink(hooks_path)).to eq(Gitlab.config.gitlab_shell.hooks_path)
end
it 'raises an error if the bundle is an attempted malicious payload' do
expect do
imported_repo.create_from_bundle(malicious_bundle_path)
end.to raise_error(::Gitlab::Git::BundleFile::InvalidBundleError)
end
end
describe '#checksum' do
......
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