<?php
/*
+-------------------------------------------------------------------------+
| Engine of the Enigma Plugin |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License version 2 |
| as published by the Free Software Foundation. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License along |
| with this program; if not, write to the Free Software Foundation, Inc., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| |
+-------------------------------------------------------------------------+
| Author: Aleksander Machniak <alec@alec.pl> |
+-------------------------------------------------------------------------+
*/
/*
RFC2440: OpenPGP Message Format
RFC3156: MIME Security with OpenPGP
RFC3851: S/MIME
*/
class enigma_engine
{
private $rc;
private $enigma;
private $pgp_driver;
private $smime_driver;
public $decryptions = array();
public $signatures = array();
public $signed_parts = array();
const PASSWORD_TIME = 120;
/**
* Plugin initialization.
*/
function __construct($enigma)
{
$this->rc = rcmail::get_instance();
$this->enigma = $enigma;
// this will remove passwords from session after some time
$this->get_passwords();
}
/**
* PGP driver initialization.
*/
function load_pgp_driver()
{
if ($this->pgp_driver) {
return;
}
$driver = 'enigma_driver_' . $this->rc->config->get('enigma_pgp_driver', 'gnupg');
$username = $this->rc->user->get_username();
// Load driver
$this->pgp_driver = new $driver($username);
if (!$this->pgp_driver) {
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: Unable to load PGP driver: $driver"
), true, true);
}
// Initialise driver
$result = $this->pgp_driver->init();
if ($result instanceof enigma_error) {
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: ".$result->getMessage()
), true, true);
}
}
/**
* S/MIME driver initialization.
*/
function load_smime_driver()
{
if ($this->smime_driver) {
return;
}
$driver = 'enigma_driver_' . $this->rc->config->get('enigma_smime_driver', 'phpssl');
$username = $this->rc->user->get_username();
// Load driver
$this->smime_driver = new $driver($username);
if (!$this->smime_driver) {
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: Unable to load S/MIME driver: $driver"
), true, true);
}
// Initialise driver
$result = $this->smime_driver->init();
if ($result instanceof enigma_error) {
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: ".$result->getMessage()
), true, true);
}
}
/**
* Handler for message_part_structure hook.
* Called for every part of the message.
*
* @param array Original parameters
*
* @return array Modified parameters
*/
function part_structure($p)
{
if ($p['mimetype'] == 'text/plain' || $p['mimetype'] == 'application/pgp') {
$this->parse_plain($p);
}
else if ($p['mimetype'] == 'multipart/signed') {
$this->parse_signed($p);
}
else if ($p['mimetype'] == 'multipart/encrypted') {
$this->parse_encrypted($p);
}
else if ($p['mimetype'] == 'application/pkcs7-mime') {
$this->parse_encrypted($p);
}
return $p;
}
/**
* Handler for message_part_body hook.
*
* @param array Original parameters
*
* @return array Modified parameters
*/
function part_body($p)
{
// encrypted attachment, see parse_plain_encrypted()
if ($p['part']->need_decryption && $p['part']->body === null) {
$storage = $this->rc->get_storage();
$body = $storage->get_message_part($p['object']->uid, $p['part']->mime_id, $p['part'], null, null, true, 0, false);
$result = $this->pgp_decrypt($body);
// @TODO: what to do on error?
if ($result === true) {
$p['part']->body = $body;
$p['part']->size = strlen($body);
$p['part']->body_modified = true;
}
}
return $p;
}
/**
* Handler for plain/text message.
*
* @param array Reference to hook's parameters
*/
function parse_plain(&$p)
{
$part = $p['structure'];
// exit, if we're already inside a decrypted message
if ($part->encrypted) {
return;
}
// Get message body from IMAP server
$body = $this->get_part_body($p['object'], $part->mime_id);
// @TODO: big message body could be a file resource
// PGP signed message
if (preg_match('/^-----BEGIN PGP SIGNED MESSAGE-----/', $body)) {
$this->parse_plain_signed($p, $body);
}
// PGP encrypted message
else if (preg_match('/^-----BEGIN PGP MESSAGE-----/', $body)) {
$this->parse_plain_encrypted($p, $body);
}
}
/**
* Handler for multipart/signed message.
*
* @param array Reference to hook's parameters
*/
function parse_signed(&$p)
{
$struct = $p['structure'];
// S/MIME
if ($struct->parts[1] && $struct->parts[1]->mimetype == 'application/pkcs7-signature') {
$this->parse_smime_signed($p);
}
// PGP/MIME: RFC3156
// The multipart/signed body MUST consist of exactly two parts.
// The first part contains the signed data in MIME canonical format,
// including a set of appropriate content headers describing the data.
// The second body MUST contain the PGP digital signature. It MUST be
// labeled with a content type of "application/pgp-signature".
else if ($struct->ctype_parameters['protocol'] == 'application/pgp-signature'
&& count($struct->parts) == 2
&& $struct->parts[1] && $struct->parts[1]->mimetype == 'application/pgp-signature'
) {
$this->parse_pgp_signed($p);
}
}
/**
* Handler for multipart/encrypted message.
*
* @param array Reference to hook's parameters
*/
function parse_encrypted(&$p)
{
$struct = $p['structure'];
// S/MIME
if ($struct->mimetype == 'application/pkcs7-mime') {
$this->parse_smime_encrypted($p);
}
// PGP/MIME: RFC3156
// The multipart/encrypted MUST consist of exactly two parts. The first
// MIME body part must have a content type of "application/pgp-encrypted".
// This body contains the control information.
// The second MIME body part MUST contain the actual encrypted data. It
// must be labeled with a content type of "application/octet-stream".
else if ($struct->ctype_parameters['protocol'] == 'application/pgp-encrypted'
&& count($struct->parts) == 2
&& $struct->parts[0] && $struct->parts[0]->mimetype == 'application/pgp-encrypted'
&& $struct->parts[1] && $struct->parts[1]->mimetype == 'application/octet-stream'
) {
$this->parse_pgp_encrypted($p);
}
}
/**
* Handler for plain signed message.
* Excludes message and signature bodies and verifies signature.
*
* @param array Reference to hook's parameters
* @param string Message (part) body
*/
private function parse_plain_signed(&$p, $body)
{
$this->load_pgp_driver();
$part = $p['structure'];
// Verify signature
if ($this->rc->action == 'show' || $this->rc->action == 'preview') {
$sig = $this->pgp_verify($body);
}
// @TODO: Handle big bodies using (temp) files
// In this way we can use fgets on string as on file handle
$fh = fopen('php://memory', 'br+');
// @TODO: fopen/fwrite errors handling
if ($fh) {
fwrite($fh, $body);
rewind($fh);
}
$body = $part->body = null;
$part->body_modified = true;
// Extract body (and signature?)
while (!feof($fh)) {
$line = fgets($fh, 1024);
if ($part->body === null)
$part->body = '';
else if (preg_match('/^-----BEGIN PGP SIGNATURE-----/', $line))
break;
else
$part->body .= $line;
}
// Remove "Hash" Armor Headers
$part->body = preg_replace('/^.*\r*\n\r*\n/', '', $part->body);
// de-Dash-Escape (RFC2440)
$part->body = preg_replace('/(^|\n)- -/', '\\1-', $part->body);
// Store signature data for display
if (!empty($sig)) {
$this->signed_parts[$part->mime_id] = $part->mime_id;
$this->signatures[$part->mime_id] = $sig;
}
fclose($fh);
}
/**
* Handler for PGP/MIME signed message.
* Verifies signature.
*
* @param array Reference to hook's parameters
*/
private function parse_pgp_signed(&$p)
{
// Verify signature
if ($this->rc->action == 'show' || $this->rc->action == 'preview') {
$this->load_pgp_driver();
$struct = $p['structure'];
$msg_part = $struct->parts[0];
$sig_part = $struct->parts[1];
// Get bodies
// Note: The first part body need to be full part body with headers
// it also cannot be decoded
$msg_body = $this->get_part_body($p['object'], $msg_part->mime_id, true);
$sig_body = $this->get_part_body($p['object'], $sig_part->mime_id);
// Verify
$sig = $this->pgp_verify($msg_body, $sig_body);
// Store signature data for display
$this->signatures[$struct->mime_id] = $sig;
// Message can be multipart (assign signature to each subpart)
if (!empty($msg_part->parts)) {
foreach ($msg_part->parts as $part)
$this->signed_parts[$part->mime_id] = $struct->mime_id;
}
else {
$this->signed_parts[$msg_part->mime_id] = $struct->mime_id;
}
// Remove signature file from attachments list (?)
unset($struct->parts[1]);
}
}
/**
* Handler for S/MIME signed message.
* Verifies signature.
*
* @param array Reference to hook's parameters
*/
private function parse_smime_signed(&$p)
{
return; // @TODO
// Verify signature
if ($this->rc->action == 'show' || $this->rc->action == 'preview') {
$this->load_smime_driver();
$struct = $p['structure'];
$msg_part = $struct->parts[0];
// Verify
$sig = $this->smime_driver->verify($struct, $p['object']);
// Store signature data for display
$this->signatures[$struct->mime_id] = $sig;
// Message can be multipart (assign signature to each subpart)
if (!empty($msg_part->parts)) {
foreach ($msg_part->parts as $part)
$this->signed_parts[$part->mime_id] = $struct->mime_id;
}
else {
$this->signed_parts[$msg_part->mime_id] = $struct->mime_id;
}
// Remove signature file from attachments list
unset($struct->parts[1]);
}
}
/**
* Handler for plain encrypted message.
*
* @param array Reference to hook's parameters
* @param string Message (part) body
*/
private function parse_plain_encrypted(&$p, $body)
{
$this->load_pgp_driver();
$part = $p['structure'];
// Decrypt
$result = $this->pgp_decrypt($body);
// Store decryption status
$this->decryptions[$part->mime_id] = $result;
// Parse decrypted message
if ($result === true) {
$part->body = $body;
$part->body_modified = true;
$part->encrypted = true;
// Encrypted plain message may contain encrypted attachments
// in such case attachments have .pgp extension and application/octet-stream.
// This is what happens when you select "Encrypt each attachment separately
// and send the message using inline PGP" in Thunderbird's Enigmail.
// find parent part ID
if (strpos($part->mime_id, '.')) {
$items = explode('.', $part->mime_id);
array_pop($items);
$parent = implode('.', $items);
}
else {
$parent = 0;
}
if ($p['object']->mime_parts[$parent]) {
foreach ((array)$p['object']->mime_parts[$parent]->parts as $p) {
if ($p->disposition == 'attachment' && $p->mimetype == 'application/octet-stream'
&& preg_match('/^(.*)\.pgp$/i', $p->filename, $m)
) {
// modify filename
$p->filename = $m[1];
// flag the part, it will be decrypted when needed
$p->need_decryption = true;
// disable caching
$p->body_modified = true;
}
}
}
}
}
/**
* Handler for PGP/MIME encrypted message.
*
* @param array Reference to hook's parameters
*/
private function parse_pgp_encrypted(&$p)
{
$this->load_pgp_driver();
$struct = $p['structure'];
$part = $struct->parts[1];
// Get body
$body = $this->get_part_body($p['object'], $part->mime_id);
// Decrypt
$result = $this->pgp_decrypt($body);
if ($result === true) {
// Parse decrypted message
$struct = $this->parse_body($body);
// Modify original message structure
$this->modify_structure($p, $struct);
// Attach the decryption message to all parts
$this->decryptions[$struct->mime_id] = $result;
foreach ((array) $struct->parts as $sp) {
$this->decryptions[$sp->mime_id] = $result;
}
}
else {
$this->decryptions[$part->mime_id] = $result;
// Make sure decryption status message will be displayed
$part->type = 'content';
$p['object']->parts[] = $part;
}
}
/**
* Handler for S/MIME encrypted message.
*
* @param array Reference to hook's parameters
*/
private function parse_smime_encrypted(&$p)
{
// $this->load_smime_driver();
}
/**
* PGP signature verification.
*
* @param mixed Message body
* @param mixed Signature body (for MIME messages)
*
* @return mixed enigma_signature or enigma_error
*/
private function pgp_verify(&$msg_body, $sig_body=null)
{
// @TODO: Handle big bodies using (temp) files
// @TODO: caching of verification result
$sig = $this->pgp_driver->verify($msg_body, $sig_body);
if (($sig instanceof enigma_error) && $sig->getCode() != enigma_error::E_KEYNOTFOUND)
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: " . $sig->getMessage()
), true, false);
return $sig;
}
/**
* PGP message decryption.
*
* @param mixed Message body
*
* @return mixed True or enigma_error
*/
private function pgp_decrypt(&$msg_body)
{
// @TODO: Handle big bodies using (temp) files
// @TODO: caching of verification result
$keys = $this->get_passwords();
$result = $this->pgp_driver->decrypt($msg_body, $keys);
if ($result instanceof enigma_error) {
$err_code = $result->getCode();
if (!in_array($err_code, array(enigma_error::E_KEYNOTFOUND, enigma_error::E_BADPASS)))
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: " . $result->getMessage()
), true, false);
return $result;
}
$msg_body = $result;
return true;
}
/**
* PGP keys listing.
*
* @param mixed Key ID/Name pattern
*
* @return mixed Array of keys or enigma_error
*/
function list_keys($pattern = '')
{
$this->load_pgp_driver();
$result = $this->pgp_driver->list_keys($pattern);
if ($result instanceof enigma_error) {
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: " . $result->getMessage()
), true, false);
}
return $result;
}
/**
* PGP key details.
*
* @param mixed Key ID
*
* @return mixed enigma_key or enigma_error
*/
function get_key($keyid)
{
$this->load_pgp_driver();
$result = $this->pgp_driver->get_key($keyid);
if ($result instanceof enigma_error) {
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: " . $result->getMessage()
), true, false);
}
return $result;
}
/**
* PGP key delete.
*
* @param string Key ID
*
* @return enigma_error|bool True on success
*/
function delete_key($keyid)
{
$this->load_pgp_driver();
$result = $this->pgp_driver->delete_key($keyid);
if ($result instanceof enigma_error) {
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: " . $result->getMessage()
), true, false);
}
return $result;
}
/**
* PGP keys/certs importing.
*
* @param mixed Import file name or content
* @param boolean True if first argument is a filename
*
* @return mixed Import status data array or enigma_error
*/
function import_key($content, $isfile=false)
{
$this->load_pgp_driver();
$result = $this->pgp_driver->import($content, $isfile);
if ($result instanceof enigma_error) {
rcube::raise_error(array(
'code' => 600, 'type' => 'php',
'file' => __FILE__, 'line' => __LINE__,
'message' => "Enigma plugin: " . $result->getMessage()
), true, false);
}
else {
$result['imported'] = $result['public_imported'] + $result['private_imported'];
$result['unchanged'] = $result['public_unchanged'] + $result['private_unchanged'];
}
return $result;
}
/**
* Handler for keys/certs import request action
*/
function import_file()
{
$uid = rcube_utils::get_input_value('_uid', rcube_utils::INPUT_POST);
$mbox = rcube_utils::get_input_value('_mbox', rcube_utils::INPUT_POST);
$mime_id = rcube_utils::get_input_value('_part', rcube_utils::INPUT_POST);
$storage = $this->rc->get_storage();
if ($uid && $mime_id) {
$storage->set_folder($mbox);
$part = $storage->get_message_part($uid, $mime_id);
}
if ($part && is_array($result = $this->import_key($part))) {
$this->rc->output->show_message('enigma.keysimportsuccess', 'confirmation',
array('new' => $result['imported'], 'old' => $result['unchanged']));
}
else
$this->rc->output->show_message('enigma.keysimportfailed', 'error');
$this->rc->output->send();
}
function password_handler()
{
$keyid = rcube_utils::get_input_value('_keyid', rcube_utils::INPUT_POST);
$passwd = rcube_utils::get_input_value('_passwd', rcube_utils::INPUT_POST, true);
if ($keyid && $passwd !== null && strlen($passwd)) {
$this->save_password($keyid, $passwd);
}
}
function save_password($keyid, $password)
{
// we store passwords in session for specified time
if ($config = $_SESSION['enigma_pass']) {
$config = $this->rc->decrypt($config);
$config = @unserialize($config);
}
$config[$keyid] = array($password, time());
$_SESSION['enigma_pass'] = $this->rc->encrypt(serialize($config));
}
function get_passwords()
{
if ($config = $_SESSION['enigma_pass']) {
$config = $this->rc->decrypt($config);
$config = @unserialize($config);
}
$threshold = time() - self::PASSWORD_TIME;
$keys = array();
// delete expired passwords
foreach ((array) $config as $key => $value) {
if ($value[1] < $threshold) {
unset($config[$key]);
$modified = true;
}
else {
$keys[$key] = $value[0];
}
}
if ($modified) {
$_SESSION['enigma_pass'] = $this->rc->encrypt(serialize($config));
}
return $keys;
}
/**
* Get message part body.
*
* @param rcube_message Message object
* @param string Message part ID
* @param bool Return raw body with headers
*/
private function get_part_body($msg, $part_id, $full = false)
{
// @TODO: Handle big bodies using file handles
if ($full) {
$storage = $this->rc->get_storage();
$body = $storage->get_raw_headers($msg->uid, $part_id);
$body .= $storage->get_raw_body($msg->uid, null, $part_id);
}
else {
$body = $msg->get_part_body($part_id, false);
}
return $body;
}
/**
* Parse decrypted message body into structure
*
* @param string Message body
*
* @return array Message structure
*/
private function parse_body(&$body)
{
// Mail_mimeDecode need \r\n end-line, but gpg may return \n
$body = preg_replace('/\r?\n/', "\r\n", $body);
// parse the body into structure
$struct = rcube_mime::parse_message($body);
return $struct;
}
/**
* Replace message encrypted structure with decrypted message structure
*
* @param array
* @param rcube_message_part
*/
private function modify_structure(&$p, $struct)
{
// modify mime_parts property of the message object
$old_id = $p['structure']->mime_id;
foreach (array_keys($p['object']->mime_parts) as $idx) {
if (!$old_id || $idx == $old_id || strpos($idx, $old_id . '.') === 0) {
unset($p['object']->mime_parts[$idx]);
}
}
// modify the new structure to be correctly handled by Roundcube
$this->modify_structure_part($struct, $p['object'], $old_id);
// replace old structure with the new one
$p['structure'] = $struct;
$p['mimetype'] = $struct->mimetype;
}
/**
* Modify decrypted message part
*
* @param rcube_message_part
* @param rcube_message
*/
private function modify_structure_part($part, $msg, $old_id)
{
// never cache the body
$part->body_modified = true;
$part->encoding = 'stream';
// Cache the fact it was decrypted
$part->encrypted = true;
// modify part identifier
if ($old_id) {
$part->mime_id = !$part->mime_id ? $old_id : ($old_id . '.' . $part->mime_id);
}
$msg->mime_parts[$part->mime_id] = $part;
// modify sub-parts
foreach ((array) $part->parts as $p) {
$this->modify_structure_part($p, $msg, $old_id);
}
}
/**
* Checks if specified message part is a PGP-key or S/MIME cert data
*
* @param rcube_message_part Part object
*
* @return boolean True if part is a key/cert
*/
public function is_keys_part($part)
{
// @TODO: S/MIME
return (
// Content-Type: application/pgp-keys
$part->mimetype == 'application/pgp-keys'
);
}
}