index.js

// avg - AVG virus scanner
'use strict'

const fs = require('node:fs')
const net = require('node:net')
const path = require('node:path')

const net_utils = require('haraka-net-utils')

const smtp_regexp = /^(\d{3})([ -])(.*)/

exports.register = function () {
  this.load_avg_ini()
}

exports.load_avg_ini = function () {
  this.cfg = this.config.get(
    'avg.ini',
    {
      booleans: ['+defer.timeout', '+defer.error'],
    },
    () => {
      this.load_avg_ini()
    },
  )
}

exports.get_tmp_file = function (transaction) {
  const tmpdir = this.cfg.main.tmpdir || '/tmp'
  return path.join(tmpdir, `${transaction.uuid}.tmp`)
}

exports.hook_data_post = function (next, connection) {
  if (!connection?.transaction) return next()

  const plugin = this
  const tmpfile = plugin.get_tmp_file(connection.transaction)
  const ws = fs.createWriteStream(tmpfile)

  ws.once('error', (err) => {
    connection.results.add(plugin, {
      err: `Error writing temporary file: ${err.message}`,
    })
    if (!plugin.cfg.defer.error) return next()
    return next(DENYSOFT, 'Virus scanner error (AVG)')
  })

  ws.once('close', () => {
    const start_time = Date.now()
    const socket = new net.Socket()
    net_utils.add_line_processor(socket)
    socket.setTimeout((plugin.cfg.main.connect_timeout || 10) * 1000)
    let connected = false
    let command = 'connect'
    let response = []

    function do_next(code, msg) {
      fs.unlink(tmpfile, () => {})
      return next(code, msg)
    }

    socket.send_command = function (cmd, data) {
      const line = cmd + (data ? ` ${data}` : '')
      connection.logprotocol(plugin, `> ${line}`)
      this.write(`${line}\r\n`)
      command = cmd.toLowerCase()
      response = []
    }

    socket.on('timeout', () => {
      const msg = `${connected ? 'connection' : 'session'} timed out`
      connection.results.add(plugin, { err: msg })
      if (!plugin.cfg.defer.timeout) return do_next()
      return do_next(DENYSOFT, 'Virus scanner timeout (AVG)')
    })

    socket.on('error', (err) => {
      connection.results.add(plugin, { err: err.message })
      if (!plugin.cfg.defer.error) return do_next()
      return do_next(DENYSOFT, 'Virus scanner error (AVG)')
    })

    socket.on('connect', function () {
      connected = true
      this.setTimeout((plugin.cfg.main.session_timeout || 30) * 1000)
    })

    socket.on('line', (line) => {
      const matches = smtp_regexp.exec(line)
      connection.logprotocol(plugin, `< ${line}`)
      if (!matches) {
        connection.results.add(plugin, {
          err: `Unrecognized response: ${line}`,
        })
        socket.end()
        if (!plugin.cfg.defer.error) return do_next()
        return do_next(DENYSOFT, 'Virus scanner error (AVG)')
      }

      const code = matches[1]
      const cont = matches[2]
      const rest = matches[3]
      response.push(rest)
      if (cont !== ' ') return

      switch (command) {
        case 'connect':
          if (code !== '220') {
            // Error
            connection.results.add(plugin, {
              err: `Unrecognized response: ${line}`,
            })
            if (!plugin.cfg.defer.timeout) return do_next()
            return do_next(DENYSOFT, 'Virus scanner error (AVG)')
          } else {
            socket.send_command('SCAN', tmpfile)
          }
          break
        case 'scan': {
          const elapsed = Date.now() - start_time
          connection.loginfo(plugin, {
            time: `${elapsed}ms`,
            code,
            response: `"${response.join(' ')}"`,
          })
          // Check code
          switch (code) {
            case '200': // 200 ok
              // Message did not contain a virus
              connection.results.add(plugin, { pass: 'clean' })
              socket.send_command('QUIT')
              return do_next()
            case '403':
              // File 'eicar.com', 'Virus identified EICAR_Test'
              connection.results.add(plugin, {
                fail: response.join(' '),
              })
              socket.send_command('QUIT')
              return do_next(DENY, response.join(' '))
            default:
              // Any other result is an error
              connection.results.add(plugin, {
                err: `Bad response: ${response.join(' ')}`,
              })
          }
          socket.send_command('QUIT')
          if (!plugin.cfg.defer.error) return do_next()
          return do_next(DENYSOFT, 'Virus scanner error (AVG)')
        }
        case 'quit':
          socket.end()
          break
        default:
          throw new Error(`Unknown command: ${command}`)
      }
    })
    socket.connect(plugin.cfg.main.port || 54322, plugin.cfg.main.host)
  })

  connection.transaction.message_stream.pipe(ws)
}