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# frozen_string_literal: true
require_relative 'helper'
require 'fileutils'
require 'tmpdir'
describe Rack::Sendfile do
def sendfile_body(filename = "rack_sendfile")
FileUtils.touch File.join(Dir.tmpdir, filename)
res = ['Hello World']
res.define_singleton_method(:to_path) { File.join(Dir.tmpdir, filename) }
res
end
def simple_app(body = sendfile_body)
lambda { |env| [200, { 'Content-Type' => 'text/plain' }, body] }
end
def sendfile_app(body, mappings = [], variation = nil)
Rack::Lint.new Rack::Sendfile.new(simple_app(body), variation, mappings)
end
def request(headers = {}, body = sendfile_body, mappings = [], variation = nil)
yield Rack::MockRequest.new(sendfile_app(body, mappings, variation)).get('/', headers)
end
def open_file(path)
Class.new(File) do
unless method_defined?(:to_path)
alias :to_path :path
end
end.open(path, 'wb+')
end
it "does nothing when no X-Sendfile-Type header present" do
request do |response|
response.must_be :ok?
response.body.must_equal 'Hello World'
response.headers.wont_include 'X-Sendfile'
end
end
it "does nothing and logs to rack.errors when incorrect X-Sendfile-Type header present" do
io = StringIO.new
# Configure with wrong variation type
request({ 'rack.errors' => io }, sendfile_body, [], 'X-Banana') do |response|
response.must_be :ok?
response.body.must_equal 'Hello World'
response.headers.wont_include 'X-Sendfile'
io.rewind
io.read.must_equal "Unknown x-sendfile variation: \"X-Banana\"\n"
end
end
it "sets x-sendfile response header and discards body" do
request({}, sendfile_body, [], 'X-Sendfile') do |response|
response.must_be :ok?
response.body.must_be :empty?
response.headers['Content-Length'].must_equal '0'
response.headers['X-Sendfile'].must_equal File.join(Dir.tmpdir, "rack_sendfile")
end
end
it "closes body when x-sendfile used" do
body = sendfile_body
closed = false
body.define_singleton_method(:close){closed = true}
request({}, body, [], 'X-Sendfile') do |response|
response.must_be :ok?
response.body.must_be :empty?
response.headers['content-length'].must_equal '0'
response.headers['x-sendfile'].must_equal File.join(Dir.tmpdir, "rack_sendfile")
end
closed.must_equal true
end
it "sets x-lighttpd-send-file response header and discards body" do
request({}, sendfile_body, [], 'X-Lighttpd-Send-File') do |response|
response.must_be :ok?
response.body.must_be :empty?
response.headers['content-length'].must_equal '0'
response.headers['x-lighttpd-send-file'].must_equal File.join(Dir.tmpdir, "rack_sendfile")
end
end
it "sets X-Accel-Redirect response header and discards body" do
headers = {
'HTTP_X_ACCEL_MAPPING' => "#{Dir.tmpdir}/=/foo/bar/"
}
request(headers, sendfile_body, [], 'X-Accel-Redirect') do |response|
response.must_be :ok?
response.body.must_be :empty?
response.headers['Content-Length'].must_equal '0'
response.headers['X-Accel-Redirect'].must_equal '/foo/bar/rack_sendfile'
end
end
it "sets X-Accel-Redirect response header to percent-encoded path" do
headers = {
'HTTP_X_ACCEL_MAPPING' => "#{Dir.tmpdir}/=/foo/bar%/"
}
request(headers, sendfile_body('file_with_%_?_symbol'), [], 'X-Accel-Redirect') do |response|
response.must_be :ok?
response.body.must_be :empty?
response.headers['Content-Length'].must_equal '0'
response.headers['X-Accel-Redirect'].must_equal '/foo/bar%25/file_with_%25_%3F_symbol'
end
end
it 'writes to rack.error when no x-accel-mapping is specified' do
request({}, sendfile_body, [], 'X-Accel-Redirect') do |response|
response.must_be :ok?
response.body.must_equal 'Hello World'
response.headers.wont_include 'X-Accel-Redirect'
response.errors.must_include 'X-Accel-Mapping'
end
end
it 'does nothing when body does not respond to #to_path' do
request({}, ['Not a file...'], [], 'X-Sendfile') do |response|
response.body.must_equal 'Not a file...'
response.headers.wont_include 'X-Sendfile'
end
end
it "sets X-Accel-Redirect response header and discards body when initialized with multiple mappings" do
begin
dir1 = Dir.mktmpdir
dir2 = Dir.mktmpdir
first_body = open_file(File.join(dir1, 'rack_sendfile'))
first_body.puts 'hello world'
second_body = open_file(File.join(dir2, 'rack_sendfile'))
second_body.puts 'goodbye world'
mappings = [
["#{dir1}/", '/foo/bar/'],
["#{dir2}/", '/wibble/']
]
request({}, first_body, mappings, 'X-Accel-Redirect') do |response|
response.must_be :ok?
response.body.must_be :empty?
response.headers['Content-Length'].must_equal '0'
response.headers['X-Accel-Redirect'].must_equal '/foo/bar/rack_sendfile'
end
request({}, second_body, mappings, 'X-Accel-Redirect') do |response|
response.must_be :ok?
response.body.must_be :empty?
response.headers['Content-Length'].must_equal '0'
response.headers['X-Accel-Redirect'].must_equal '/wibble/rack_sendfile'
end
ensure
FileUtils.remove_entry_secure dir1
FileUtils.remove_entry_secure dir2
end
end
it "sets X-Accel-Redirect response header and discards body when initialized with multiple mappings via header" do
begin
dir1 = Dir.mktmpdir
dir2 = Dir.mktmpdir
dir3 = Dir.mktmpdir
first_body = open_file(File.join(dir1, 'rack_sendfile'))
first_body.puts 'hello world'
second_body = open_file(File.join(dir2, 'rack_sendfile'))
second_body.puts 'goodbye world'
third_body = open_file(File.join(dir3, 'rack_sendfile'))
third_body.puts 'hello again world'
# Now we need to explicitly enable x-accel-redirect in the constructor
app = Rack::Lint.new Rack::Sendfile.new(simple_app(first_body), "X-Accel-Redirect", [])
headers = {
'HTTP_X_ACCEL_MAPPING' => "#{dir1}/=/foo/bar/, #{dir2}/=/wibble/"
}
response = Rack::MockRequest.new(app).get('/', headers)
response.must_be :ok?
response.body.must_be :empty?
response.headers['content-length'].must_equal '0'
response.headers['x-accel-redirect'].must_equal '/foo/bar/rack_sendfile'
app = Rack::Lint.new Rack::Sendfile.new(simple_app(second_body), "X-Accel-Redirect", [])
response = Rack::MockRequest.new(app).get('/', headers)
response.must_be :ok?
response.body.must_be :empty?
response.headers['content-length'].must_equal '0'
response.headers['x-accel-redirect'].must_equal '/wibble/rack_sendfile'
app = Rack::Lint.new Rack::Sendfile.new(simple_app(third_body), "X-Accel-Redirect", [])
response = Rack::MockRequest.new(app).get('/', headers)
response.must_be :ok?
response.body.must_be :empty?
response.headers['content-length'].must_equal '0'
response.headers['x-accel-redirect'].must_equal "#{dir3}/rack_sendfile"
ensure
FileUtils.remove_entry_secure dir1
FileUtils.remove_entry_secure dir2
FileUtils.remove_entry_secure dir3
end
end
# Security tests for CVE mitigation
describe "security: information disclosure prevention" do
it "ignores HTTP_X_SENDFILE_TYPE header to prevent attacker-controlled sendfile activation" do
# Attacker tries to enable x-sendfile via header
request 'HTTP_X_SENDFILE_TYPE' => 'x-sendfile' do |response|
response.must_be :ok?
response.body.must_equal 'Hello World'
response.headers.wont_include 'x-sendfile'
end
end
it "ignores HTTP_X_SENDFILE_TYPE header attempting to enable x-accel-redirect" do
# Attacker tries to enable x-accel-redirect via header with mapping
headers = {
'HTTP_X_SENDFILE_TYPE' => 'x-accel-redirect',
'HTTP_X_ACCEL_MAPPING' => "#{Dir.tmpdir}/=/attacker/path/"
}
request headers do |response|
response.must_be :ok?
response.body.must_equal 'Hello World'
response.headers.wont_include 'x-accel-redirect'
end
end
it "ignores HTTP_X_ACCEL_MAPPING when x-accel-redirect is not explicitly enabled" do
# Even if attacker sends mapping header, it should be ignored without explicit config
headers = {
'HTTP_X_ACCEL_MAPPING' => "#{Dir.tmpdir}/=/attacker/path/"
}
request headers do |response|
response.must_be :ok?
response.body.must_equal 'Hello World'
response.headers.wont_include 'x-accel-redirect'
end
end
it "ignores HTTP_X_ACCEL_MAPPING when application-level mappings are configured" do
# When app provides mappings, header should be ignored for security
begin
dir = Dir.mktmpdir
body = open_file(File.join(dir, 'rack_sendfile'))
body.puts 'test'
app_mappings = [["#{dir}/", '/app/mapping/']]
app = Rack::Lint.new Rack::Sendfile.new(simple_app(body), "X-Accel-Redirect", app_mappings)
headers = {
'HTTP_X_ACCEL_MAPPING' => "#{dir}/=/attacker/path/"
}
response = Rack::MockRequest.new(app).get('/', headers)
response.must_be :ok?
response.body.must_be :empty?
response.headers['x-accel-redirect'].must_equal '/app/mapping/rack_sendfile'
response.headers['x-accel-redirect'].wont_equal '/attacker/path/rack_sendfile'
ensure
FileUtils.remove_entry_secure dir
end
end
it "allows HTTP_X_ACCEL_MAPPING only when x-accel-redirect explicitly enabled with no app mappings" do
# This is the safe use case: explicit config + no app mappings = allow header
begin
dir = Dir.mktmpdir
body = open_file(File.join(dir, 'rack_sendfile'))
body.puts 'test'
app = Rack::Lint.new Rack::Sendfile.new(simple_app(body), "X-Accel-Redirect", [])
headers = {
'HTTP_X_ACCEL_MAPPING' => "#{dir}/=/safe/nginx/mapping/"
}
response = Rack::MockRequest.new(app).get('/', headers)
response.must_be :ok?
response.body.must_be :empty?
response.headers['x-accel-redirect'].must_equal '/safe/nginx/mapping/rack_sendfile'
ensure
FileUtils.remove_entry_secure dir
end
end
it "does not allow x-lighttpd-send-file activation via header" do
# Verify other sendfile types also can't be enabled via headers
request 'HTTP_X_SENDFILE_TYPE' => 'x-lighttpd-send-file' do |response|
response.must_be :ok?
response.body.must_equal 'Hello World'
response.headers.wont_include 'x-lighttpd-send-file'
end
end
it "requires explicit middleware configuration for any sendfile variation" do
# Test that sendfile.type env var still works (internal, not from HTTP headers)
body = sendfile_body
app = lambda { |env| [200, { 'content-type' => 'text/plain' }, body] }
middleware = Rack::Lint.new Rack::Sendfile.new(app)
env = Rack::MockRequest.env_for('/', { 'sendfile.type' => 'X-Sendfile' })
status, headers, response_body = middleware.call(env)
status.must_equal 200
headers['X-Sendfile'].must_equal File.join(Dir.tmpdir, "rack_sendfile")
headers['Content-Length'].must_equal '0'
end
end
end
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