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<?php
/*
* This file is part of SwiftMailer.
* (c) 2004-2009 Chris Corbyn
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
/**
* DKIM Signer used to apply DKIM Signature to a message.
*
* @author Xavier De Cock <xdecock@gmail.com>
*/
class Swift_Signers_DKIMSigner implements Swift_Signers_HeaderSigner
{
/**
* PrivateKey.
*
* @var string
*/
protected $privateKey;
/**
* DomainName.
*
* @var string
*/
protected $domainName;
/**
* Selector.
*
* @var string
*/
protected $selector;
private $passphrase = '';
/**
* Hash algorithm used.
*
* @see RFC6376 3.3: Signers MUST implement and SHOULD sign using rsa-sha256.
*
* @var string
*/
protected $hashAlgorithm = 'rsa-sha256';
/**
* Body canon method.
*
* @var string
*/
protected $bodyCanon = 'simple';
/**
* Header canon method.
*
* @var string
*/
protected $headerCanon = 'simple';
/**
* Headers not being signed.
*
* @var array
*/
protected $ignoredHeaders = ['return-path' => true];
/**
* Signer identity.
*
* @var string
*/
protected $signerIdentity;
/**
* BodyLength.
*
* @var int
*/
protected $bodyLen = 0;
/**
* Maximum signedLen.
*
* @var int
*/
protected $maxLen = PHP_INT_MAX;
/**
* Embbed bodyLen in signature.
*
* @var bool
*/
protected $showLen = false;
/**
* When the signature has been applied (true means time()), false means not embedded.
*
* @var mixed
*/
protected $signatureTimestamp = true;
/**
* When will the signature expires false means not embedded, if sigTimestamp is auto
* Expiration is relative, otherwise it's absolute.
*
* @var int
*/
protected $signatureExpiration = false;
/**
* Must we embed signed headers?
*
* @var bool
*/
protected $debugHeaders = false;
// work variables
/**
* Headers used to generate hash.
*
* @var array
*/
protected $signedHeaders = [];
/**
* If debugHeaders is set store debugData here.
*
* @var string[]
*/
private $debugHeadersData = [];
/**
* Stores the bodyHash.
*
* @var string
*/
private $bodyHash = '';
/**
* Stores the signature header.
*
* @var Swift_Mime_Headers_ParameterizedHeader
*/
protected $dkimHeader;
private $bodyHashHandler;
private $headerHash;
private $headerCanonData = '';
private $bodyCanonEmptyCounter = 0;
private $bodyCanonIgnoreStart = 2;
private $bodyCanonSpace = false;
private $bodyCanonLastChar = null;
private $bodyCanonLine = '';
private $bound = [];
/**
* Constructor.
*
* @param string $privateKey
* @param string $domainName
* @param string $selector
* @param string $passphrase
*/
public function __construct($privateKey, $domainName, $selector, $passphrase = '')
{
$this->privateKey = $privateKey;
$this->domainName = $domainName;
$this->signerIdentity = '@'.$domainName;
$this->selector = $selector;
$this->passphrase = $passphrase;
}
/**
* Reset the Signer.
*
* @see Swift_Signer::reset()
*/
public function reset()
{
$this->headerHash = null;
$this->signedHeaders = [];
$this->bodyHash = null;
$this->bodyHashHandler = null;
$this->bodyCanonIgnoreStart = 2;
$this->bodyCanonEmptyCounter = 0;
$this->bodyCanonLastChar = null;
$this->bodyCanonSpace = false;
}
/**
* Writes $bytes to the end of the stream.
*
* Writing may not happen immediately if the stream chooses to buffer. If
* you want to write these bytes with immediate effect, call {@link commit()}
* after calling write().
*
* This method returns the sequence ID of the write (i.e. 1 for first, 2 for
* second, etc etc).
*
* @param string $bytes
*
* @return int
*
* @throws Swift_IoException
*/
// TODO fix return
public function write($bytes)
{
$this->canonicalizeBody($bytes);
foreach ($this->bound as $is) {
$is->write($bytes);
}
}
/**
* For any bytes that are currently buffered inside the stream, force them
* off the buffer.
*/
public function commit()
{
// Nothing to do
return;
}
/**
* Attach $is to this stream.
*
* The stream acts as an observer, receiving all data that is written.
* All {@link write()} and {@link flushBuffers()} operations will be mirrored.
*/
public function bind(Swift_InputByteStream $is)
{
// Don't have to mirror anything
$this->bound[] = $is;
return;
}
/**
* Remove an already bound stream.
*
* If $is is not bound, no errors will be raised.
* If the stream currently has any buffered data it will be written to $is
* before unbinding occurs.
*/
public function unbind(Swift_InputByteStream $is)
{
// Don't have to mirror anything
foreach ($this->bound as $k => $stream) {
if ($stream === $is) {
unset($this->bound[$k]);
return;
}
}
}
/**
* Flush the contents of the stream (empty it) and set the internal pointer
* to the beginning.
*
* @throws Swift_IoException
*/
public function flushBuffers()
{
$this->reset();
}
/**
* Set hash_algorithm, must be one of rsa-sha256 | rsa-sha1.
*
* @param string $hash 'rsa-sha1' or 'rsa-sha256'
*
* @throws Swift_SwiftException
*
* @return $this
*/
public function setHashAlgorithm($hash)
{
switch ($hash) {
case 'rsa-sha1':
$this->hashAlgorithm = 'rsa-sha1';
break;
case 'rsa-sha256':
$this->hashAlgorithm = 'rsa-sha256';
if (!\defined('OPENSSL_ALGO_SHA256')) {
throw new Swift_SwiftException('Unable to set sha256 as it is not supported by OpenSSL.');
}
break;
default:
throw new Swift_SwiftException('Unable to set the hash algorithm, must be one of rsa-sha1 or rsa-sha256 (%s given).', $hash);
}
return $this;
}
/**
* Set the body canonicalization algorithm.
*
* @param string $canon
*
* @return $this
*/
public function setBodyCanon($canon)
{
if ('relaxed' == $canon) {
$this->bodyCanon = 'relaxed';
} else {
$this->bodyCanon = 'simple';
}
return $this;
}
/**
* Set the header canonicalization algorithm.
*
* @param string $canon
*
* @return $this
*/
public function setHeaderCanon($canon)
{
if ('relaxed' == $canon) {
$this->headerCanon = 'relaxed';
} else {
$this->headerCanon = 'simple';
}
return $this;
}
/**
* Set the signer identity.
*
* @param string $identity
*
* @return $this
*/
public function setSignerIdentity($identity)
{
$this->signerIdentity = $identity;
return $this;
}
/**
* Set the length of the body to sign.
*
* @param mixed $len (bool or int)
*
* @return $this
*/
public function setBodySignedLen($len)
{
if (true === $len) {
$this->showLen = true;
$this->maxLen = PHP_INT_MAX;
} elseif (false === $len) {
$this->showLen = false;
$this->maxLen = PHP_INT_MAX;
} else {
$this->showLen = true;
$this->maxLen = (int) $len;
}
return $this;
}
/**
* Set the signature timestamp.
*
* @param int $time A timestamp
*
* @return $this
*/
public function setSignatureTimestamp($time)
{
$this->signatureTimestamp = $time;
return $this;
}
/**
* Set the signature expiration timestamp.
*
* @param int $time A timestamp
*
* @return $this
*/
public function setSignatureExpiration($time)
{
$this->signatureExpiration = $time;
return $this;
}
/**
* Enable / disable the DebugHeaders.
*
* @param bool $debug
*
* @return Swift_Signers_DKIMSigner
*/
public function setDebugHeaders($debug)
{
$this->debugHeaders = (bool) $debug;
return $this;
}
/**
* Start Body.
*/
public function startBody()
{
// Init
switch ($this->hashAlgorithm) {
case 'rsa-sha256':
$this->bodyHashHandler = hash_init('sha256');
break;
case 'rsa-sha1':
$this->bodyHashHandler = hash_init('sha1');
break;
}
$this->bodyCanonLine = '';
}
/**
* End Body.
*/
public function endBody()
{
$this->endOfBody();
}
/**
* Returns the list of Headers Tampered by this plugin.
*
* @return array
*/
public function getAlteredHeaders()
{
if ($this->debugHeaders) {
return ['DKIM-Signature', 'X-DebugHash'];
} else {
return ['DKIM-Signature'];
}
}
/**
* Adds an ignored Header.
*
* @param string $header_name
*
* @return Swift_Signers_DKIMSigner
*/
public function ignoreHeader($header_name)
{
$this->ignoredHeaders[strtolower($header_name)] = true;
return $this;
}
/**
* Set the headers to sign.
*
* @return Swift_Signers_DKIMSigner
*/
public function setHeaders(Swift_Mime_SimpleHeaderSet $headers)
{
$this->headerCanonData = '';
// Loop through Headers
$listHeaders = $headers->listAll();
foreach ($listHeaders as $hName) {
// Check if we need to ignore Header
if (!isset($this->ignoredHeaders[strtolower($hName)])) {
if ($headers->has($hName)) {
$tmp = $headers->getAll($hName);
foreach ($tmp as $header) {
if ('' != $header->getFieldBody()) {
$this->addHeader($header->toString());
$this->signedHeaders[] = $header->getFieldName();
}
}
}
}
}
return $this;
}
/**
* Add the signature to the given Headers.
*
* @return Swift_Signers_DKIMSigner
*/
public function addSignature(Swift_Mime_SimpleHeaderSet $headers)
{
// Prepare the DKIM-Signature
$params = ['v' => '1', 'a' => $this->hashAlgorithm, 'bh' => base64_encode($this->bodyHash), 'd' => $this->domainName, 'h' => implode(': ', $this->signedHeaders), 'i' => $this->signerIdentity, 's' => $this->selector];
if ('simple' != $this->bodyCanon) {
$params['c'] = $this->headerCanon.'/'.$this->bodyCanon;
} elseif ('simple' != $this->headerCanon) {
$params['c'] = $this->headerCanon;
}
if ($this->showLen) {
$params['l'] = $this->bodyLen;
}
if (true === $this->signatureTimestamp) {
$params['t'] = time();
if (false !== $this->signatureExpiration) {
$params['x'] = $params['t'] + $this->signatureExpiration;
}
} else {
if (false !== $this->signatureTimestamp) {
$params['t'] = $this->signatureTimestamp;
}
if (false !== $this->signatureExpiration) {
$params['x'] = $this->signatureExpiration;
}
}
if ($this->debugHeaders) {
$params['z'] = implode('|', $this->debugHeadersData);
}
$string = '';
foreach ($params as $k => $v) {
$string .= $k.'='.$v.'; ';
}
$string = trim($string);
$headers->addTextHeader('DKIM-Signature', $string);
// Add the last DKIM-Signature
$tmp = $headers->getAll('DKIM-Signature');
$this->dkimHeader = end($tmp);
$this->addHeader(trim($this->dkimHeader->toString())."\r\n b=", true);
if ($this->debugHeaders) {
$headers->addTextHeader('X-DebugHash', base64_encode($this->headerHash));
}
$this->dkimHeader->setValue($string.' b='.trim(chunk_split(base64_encode($this->getEncryptedHash()), 73, ' ')));
return $this;
}
/* Private helpers */
protected function addHeader($header, $is_sig = false)
{
switch ($this->headerCanon) {
case 'relaxed':
// Prepare Header and cascade
$exploded = explode(':', $header, 2);
$name = strtolower(trim($exploded[0]));
$value = str_replace("\r\n", '', $exploded[1]);
$value = preg_replace("/[ \t][ \t]+/", ' ', $value);
$header = $name.':'.trim($value).($is_sig ? '' : "\r\n");
// no break
case 'simple':
// Nothing to do
}
$this->addToHeaderHash($header);
}
protected function canonicalizeBody($string)
{
$len = \strlen($string);
$canon = '';
$method = ('relaxed' == $this->bodyCanon);
for ($i = 0; $i < $len; ++$i) {
if ($this->bodyCanonIgnoreStart > 0) {
--$this->bodyCanonIgnoreStart;
continue;
}
switch ($string[$i]) {
case "\r":
$this->bodyCanonLastChar = "\r";
break;
case "\n":
if ("\r" == $this->bodyCanonLastChar) {
if ($method) {
$this->bodyCanonSpace = false;
}
if ('' == $this->bodyCanonLine) {
++$this->bodyCanonEmptyCounter;
} else {
$this->bodyCanonLine = '';
$canon .= "\r\n";
}
} else {
// Wooops Error
// todo handle it but should never happen
}
break;
case ' ':
case "\t":
if ($method) {
$this->bodyCanonSpace = true;
break;
}
// no break
default:
if ($this->bodyCanonEmptyCounter > 0) {
$canon .= str_repeat("\r\n", $this->bodyCanonEmptyCounter);
$this->bodyCanonEmptyCounter = 0;
}
if ($this->bodyCanonSpace) {
$this->bodyCanonLine .= ' ';
$canon .= ' ';
$this->bodyCanonSpace = false;
}
$this->bodyCanonLine .= $string[$i];
$canon .= $string[$i];
}
}
$this->addToBodyHash($canon);
}
protected function endOfBody()
{
// Add trailing Line return if last line is non empty
if (\strlen($this->bodyCanonLine) > 0) {
$this->addToBodyHash("\r\n");
}
$this->bodyHash = hash_final($this->bodyHashHandler, true);
}
private function addToBodyHash($string)
{
$len = \strlen($string);
if ($len > ($new_len = ($this->maxLen - $this->bodyLen))) {
$string = substr($string, 0, $new_len);
$len = $new_len;
}
hash_update($this->bodyHashHandler, $string);
$this->bodyLen += $len;
}
private function addToHeaderHash($header)
{
if ($this->debugHeaders) {
$this->debugHeadersData[] = trim($header);
}
$this->headerCanonData .= $header;
}
/**
* @throws Swift_SwiftException
*
* @return string
*/
private function getEncryptedHash()
{
$signature = '';
switch ($this->hashAlgorithm) {
case 'rsa-sha1':
$algorithm = OPENSSL_ALGO_SHA1;
break;
case 'rsa-sha256':
$algorithm = OPENSSL_ALGO_SHA256;
break;
}
$pkeyId = openssl_get_privatekey($this->privateKey, $this->passphrase);
if (!$pkeyId) {
throw new Swift_SwiftException('Unable to load DKIM Private Key ['.openssl_error_string().']');
}
if (openssl_sign($this->headerCanonData, $signature, $pkeyId, $algorithm)) {
return $signature;
}
throw new Swift_SwiftException('Unable to sign DKIM Hash ['.openssl_error_string().']');
}
}
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