From 64c5045c0a6b84fdb938a8465a0890e5f7162708 Mon Sep 17 00:00:00 2001 From: Yusuke Endoh Date: Tue, 22 Nov 2022 10:49:27 +0900 Subject: [PATCH] Prevent CRLF injection Throw a RuntimeError if the HTTP response header contains CR or LF to prevent HTTP response splitting. https://hackerone.com/reports/1204695 Upstream-Status: Backport [https://github.com/ruby/cgi/commit/64c5045c0a6b84fdb938a8465a0890e5f7162708] CVE: CVE-2021-33621 Signed-off-by: Hitendra Prajapati --- lib/cgi/core.rb | 45 +++++++++++++++++++++++-------------- test/cgi/test_cgi_header.rb | 8 +++++++ 2 files changed, 36 insertions(+), 17 deletions(-) diff --git a/lib/cgi/core.rb b/lib/cgi/core.rb index bec76e0..62e6068 100644 --- a/lib/cgi/core.rb +++ b/lib/cgi/core.rb @@ -188,17 +188,28 @@ class CGI # Using #header with the HTML5 tag maker will create a
element. alias :header :http_header + def _no_crlf_check(str) + if str + str = str.to_s + raise "A HTTP status or header field must not include CR and LF" if str =~ /[\r\n]/ + str + else + nil + end + end + private :_no_crlf_check + def _header_for_string(content_type) #:nodoc: buf = ''.dup if nph?() - buf << "#{$CGI_ENV['SERVER_PROTOCOL'] || 'HTTP/1.0'} 200 OK#{EOL}" + buf << "#{_no_crlf_check($CGI_ENV['SERVER_PROTOCOL']) || 'HTTP/1.0'} 200 OK#{EOL}" buf << "Date: #{CGI.rfc1123_date(Time.now)}#{EOL}" - buf << "Server: #{$CGI_ENV['SERVER_SOFTWARE']}#{EOL}" + buf << "Server: #{_no_crlf_check($CGI_ENV['SERVER_SOFTWARE'])}#{EOL}" buf << "Connection: close#{EOL}" end - buf << "Content-Type: #{content_type}#{EOL}" + buf << "Content-Type: #{_no_crlf_check(content_type)}#{EOL}" if @output_cookies - @output_cookies.each {|cookie| buf << "Set-Cookie: #{cookie}#{EOL}" } + @output_cookies.each {|cookie| buf << "Set-Cookie: #{_no_crlf_check(cookie)}#{EOL}" } end return buf end # _header_for_string @@ -213,9 +224,9 @@ class CGI ## NPH options.delete('nph') if defined?(MOD_RUBY) if options.delete('nph') || nph?() - protocol = $CGI_ENV['SERVER_PROTOCOL'] || 'HTTP/1.0' + protocol = _no_crlf_check($CGI_ENV['SERVER_PROTOCOL']) || 'HTTP/1.0' status = options.delete('status') - status = HTTP_STATUS[status] || status || '200 OK' + status = HTTP_STATUS[status] || _no_crlf_check(status) || '200 OK' buf << "#{protocol} #{status}#{EOL}" buf << "Date: #{CGI.rfc1123_date(Time.now)}#{EOL}" options['server'] ||= $CGI_ENV['SERVER_SOFTWARE'] || '' @@ -223,38 +234,38 @@ class CGI end ## common headers status = options.delete('status') - buf << "Status: #{HTTP_STATUS[status] || status}#{EOL}" if status + buf << "Status: #{HTTP_STATUS[status] || _no_crlf_check(status)}#{EOL}" if status server = options.delete('server') - buf << "Server: #{server}#{EOL}" if server + buf << "Server: #{_no_crlf_check(server)}#{EOL}" if server connection = options.delete('connection') - buf << "Connection: #{connection}#{EOL}" if connection + buf << "Connection: #{_no_crlf_check(connection)}#{EOL}" if connection type = options.delete('type') - buf << "Content-Type: #{type}#{EOL}" #if type + buf << "Content-Type: #{_no_crlf_check(type)}#{EOL}" #if type length = options.delete('length') - buf << "Content-Length: #{length}#{EOL}" if length + buf << "Content-Length: #{_no_crlf_check(length)}#{EOL}" if length language = options.delete('language') - buf << "Content-Language: #{language}#{EOL}" if language + buf << "Content-Language: #{_no_crlf_check(language)}#{EOL}" if language expires = options.delete('expires') buf << "Expires: #{CGI.rfc1123_date(expires)}#{EOL}" if expires ## cookie if cookie = options.delete('cookie') case cookie when String, Cookie - buf << "Set-Cookie: #{cookie}#{EOL}" + buf << "Set-Cookie: #{_no_crlf_check(cookie)}#{EOL}" when Array arr = cookie - arr.each {|c| buf << "Set-Cookie: #{c}#{EOL}" } + arr.each {|c| buf << "Set-Cookie: #{_no_crlf_check(c)}#{EOL}" } when Hash hash = cookie - hash.each_value {|c| buf << "Set-Cookie: #{c}#{EOL}" } + hash.each_value {|c| buf << "Set-Cookie: #{_no_crlf_check(c)}#{EOL}" } end end if @output_cookies - @output_cookies.each {|c| buf << "Set-Cookie: #{c}#{EOL}" } + @output_cookies.each {|c| buf << "Set-Cookie: #{_no_crlf_check(c)}#{EOL}" } end ## other headers options.each do |key, value| - buf << "#{key}: #{value}#{EOL}" + buf << "#{_no_crlf_check(key)}: #{_no_crlf_check(value)}#{EOL}" end return buf end # _header_for_hash diff --git a/test/cgi/test_cgi_header.rb b/test/cgi/test_cgi_header.rb index bab2d03..ec2f4de 100644 --- a/test/cgi/test_cgi_header.rb +++ b/test/cgi/test_cgi_header.rb @@ -176,6 +176,14 @@ class CGIHeaderTest < Test::Unit::TestCase end + def test_cgi_http_header_crlf_injection + cgi = CGI.new + assert_raise(RuntimeError) { cgi.http_header("text/xhtml\r\nBOO") } + assert_raise(RuntimeError) { cgi.http_header("type" => "text/xhtml\r\nBOO") } + assert_raise(RuntimeError) { cgi.http_header("status" => "200 OK\r\nBOO") } + assert_raise(RuntimeError) { cgi.http_header("location" => "text/xhtml\r\nBOO") } + end + instance_methods.each do |method| private method if method =~ /^test_(.*)/ && $1 != ENV['TEST'] -- 2.25.1