<?php
namespace Sabre\HTTP;
/**
* HTTP AWS Authentication handler
*
* Use this class to leverage amazon's AWS authentication header
*
* @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
* @author Evert Pot (http://evertpot.com/)
* @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
*/
class AWSAuth extends AbstractAuth {
/**
* The signature supplied by the HTTP client
*
* @var string
*/
private $signature = null;
/**
* The accesskey supplied by the HTTP client
*
* @var string
*/
private $accessKey = null;
/**
* An error code, if any
*
* This value will be filled with one of the ERR_* constants
*
* @var int
*/
public $errorCode = 0;
const ERR_NOAWSHEADER = 1;
const ERR_MD5CHECKSUMWRONG = 2;
const ERR_INVALIDDATEFORMAT = 3;
const ERR_REQUESTTIMESKEWED = 4;
const ERR_INVALIDSIGNATURE = 5;
/**
* Gathers all information from the headers
*
* This method needs to be called prior to anything else.
*
* @return bool
*/
public function init() {
$authHeader = $this->httpRequest->getHeader('Authorization');
$authHeader = explode(' ',$authHeader);
if ($authHeader[0]!='AWS' || !isset($authHeader[1])) {
$this->errorCode = self::ERR_NOAWSHEADER;
return false;
}
list($this->accessKey,$this->signature) = explode(':',$authHeader[1]);
return true;
}
/**
* Returns the username for the request
*
* @return string
*/
public function getAccessKey() {
return $this->accessKey;
}
/**
* Validates the signature based on the secretKey
*
* @param string $secretKey
* @return bool
*/
public function validate($secretKey) {
$contentMD5 = $this->httpRequest->getHeader('Content-MD5');
if ($contentMD5) {
// We need to validate the integrity of the request
$body = $this->httpRequest->getBody(true);
$this->httpRequest->setBody($body,true);
if ($contentMD5!=base64_encode(md5($body,true))) {
// content-md5 header did not match md5 signature of body
$this->errorCode = self::ERR_MD5CHECKSUMWRONG;
return false;
}
}
if (!$requestDate = $this->httpRequest->getHeader('x-amz-date'))
$requestDate = $this->httpRequest->getHeader('Date');
if (!$this->validateRFC2616Date($requestDate))
return false;
$amzHeaders = $this->getAmzHeaders();
$signature = base64_encode(
$this->hmacsha1($secretKey,
$this->httpRequest->getMethod() . "\n" .
$contentMD5 . "\n" .
$this->httpRequest->getHeader('Content-type') . "\n" .
$requestDate . "\n" .
$amzHeaders .
$this->httpRequest->getURI()
)
);
if ($this->signature != $signature) {
$this->errorCode = self::ERR_INVALIDSIGNATURE;
return false;
}
return true;
}
/**
* Returns an HTTP 401 header, forcing login
*
* This should be called when username and password are incorrect, or not supplied at all
*
* @return void
*/
public function requireLogin() {
$this->httpResponse->setHeader('WWW-Authenticate','AWS');
$this->httpResponse->sendStatus(401);
}
/**
* Makes sure the supplied value is a valid RFC2616 date.
*
* If we would just use strtotime to get a valid timestamp, we have no way of checking if a
* user just supplied the word 'now' for the date header.
*
* This function also makes sure the Date header is within 15 minutes of the operating
* system date, to prevent replay attacks.
*
* @param string $dateHeader
* @return bool
*/
protected function validateRFC2616Date($dateHeader) {
$date = Util::parseHTTPDate($dateHeader);
// Unknown format
if (!$date) {
$this->errorCode = self::ERR_INVALIDDATEFORMAT;
return false;
}
$min = new \DateTime('-15 minutes');
$max = new \DateTime('+15 minutes');
// We allow 15 minutes around the current date/time
if ($date > $max || $date < $min) {
$this->errorCode = self::ERR_REQUESTTIMESKEWED;
return false;
}
return $date;
}
/**
* Returns a list of AMZ headers
*
* @return string
*/
protected function getAmzHeaders() {
$amzHeaders = array();
$headers = $this->httpRequest->getHeaders();
foreach($headers as $headerName => $headerValue) {
if (strpos(strtolower($headerName),'x-amz-')===0) {
$amzHeaders[strtolower($headerName)] = str_replace(array("\r\n"),array(' '),$headerValue) . "\n";
}
}
ksort($amzHeaders);
$headerStr = '';
foreach($amzHeaders as $h=>$v) {
$headerStr.=$h.':'.$v;
}
return $headerStr;
}
/**
* Generates an HMAC-SHA1 signature
*
* @param string $key
* @param string $message
* @return string
*/
private function hmacsha1($key, $message) {
$blocksize=64;
if (strlen($key)>$blocksize)
$key=pack('H*', sha1($key));
$key=str_pad($key,$blocksize,chr(0x00));
$ipad=str_repeat(chr(0x36),$blocksize);
$opad=str_repeat(chr(0x5c),$blocksize);
$hmac = pack('H*',sha1(($key^$opad).pack('H*',sha1(($key^$ipad).$message))));
return $hmac;
}
}
