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libphutil/src/future/aws/PhutilAWSv4Signature.php
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PhutilAWSv4Signature.php
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<?php
final class PhutilAWSv4Signature extends Phobject {
private $accessKey;
private $secretKey;
private $signingKey;
private $date;
private $region;
private $service;
public function setAccessKey($access_key) {
$this->accessKey = $access_key;
return $this;
}
public function setSecretKey(PhutilOpaqueEnvelope $secret_key) {
$this->secretKey = $secret_key;
return $this;
}
public function setDate($date) {
$this->date = $date;
return $this;
}
public function getDate() {
if ($this->date === null) {
$this->date = gmdate('Ymd\THis\Z', time());
}
return $this->date;
}
public function setRegion($region) {
$this->region = $region;
return $this;
}
public function getRegion() {
return $this->region;
}
public function setService($service) {
$this->service = $service;
return $this;
}
public function getService() {
return $this->service;
}
public function setSigningKey($signing_key) {
$this->signingKey = $signing_key;
return $this;
}
public function getSigningKey() {
if ($this->signingKey === null) {
$this->signingKey = $this->computeSigningKey();
}
return $this->signingKey;
}
private function getAlgorithm() {
return 'AWS4-HMAC-SHA256';
}
private function getHost(HTTPSFuture $future) {
$uri = new PhutilURI($future->getURI());
return $uri->getDomain();
}
private function getPath(HTTPSFuture $future) {
$uri = new PhutilURI($future->getURI());
return $uri->getPath();
}
public function signRequest(HTTPSFuture $future) {
$body_signature = $this->getBodySignature($future);
$future->addHeader('X-Amz-Content-sha256', $body_signature);
$future->addHeader('X-Amz-Date', $this->getDate());
$request_signature = $this->getCanonicalRequestSignature(
$future,
$body_signature);
$string_to_sign = $this->getStringToSign($request_signature);
$signing_key = $this->getSigningKey();
$signature = hash_hmac('sha256', $string_to_sign, $signing_key);
$algorithm = $this->getAlgorithm();
$credential = $this->getCredential();
$signed_headers = $this->getSignedHeaderList($future);
$authorization =
$algorithm.' '.
'Credential='.$credential.','.
'SignedHeaders='.$signed_headers.','.
'Signature='.$signature;
$future->addHeader('Authorization', $authorization);
return $future;
}
private function getBodySignature(HTTPSFuture $future) {
$http_body = $future->getData();
if (is_array($http_body)) {
$http_body = '';
}
return hash('sha256', $http_body);
}
private function getCanonicalRequestSignature(
HTTPSFuture $future,
$body_signature) {
$http_method = $future->getMethod();
$path = $this->getPath($future);
$path = rawurlencode($path);
$path = str_replace('%2F', '/', $path);
$canonical_parameters = $this->getCanonicalParameterList($future);
$canonical_headers = $this->getCanonicalHeaderList($future);
$signed_headers = $this->getSignedHeaderList($future);
$canonical_request =
$http_method."\n".
$path."\n".
$canonical_parameters."\n".
$canonical_headers."\n".
"\n".
$signed_headers."\n".
$body_signature;
return hash('sha256', $canonical_request);
}
private function getStringToSign($request_signature) {
$algorithm = $this->getAlgorithm();
$date = $this->getDate();
$scope_parts = $this->getScopeParts();
$scope = implode('/', $scope_parts);
$string_to_sign =
$algorithm."\n".
$date."\n".
$scope."\n".
$request_signature;
return $string_to_sign;
}
private function getScopeParts() {
return array(
substr($this->getDate(), 0, 8),
$this->getRegion(),
$this->getService(),
'aws4_request',
);
}
private function computeSigningKey() {
$secret_key = $this->secretKey;
if (!$secret_key) {
throw new Exception(
pht(
'You must either provide a signing key with setSigningKey(), or '.
'provide a secret key with setSecretKey().'));
}
// NOTE: This part of the algorithm uses the raw binary hashes, and the
// result is not human-readable.
$raw_hash = true;
$signing_key = 'AWS4'.$secret_key->openEnvelope();
$scope_parts = $this->getScopeParts();
foreach ($scope_parts as $scope_part) {
$signing_key = hash_hmac('sha256', $scope_part, $signing_key, $raw_hash);
}
return $signing_key;
}
private function getCanonicalHeaderList(HTTPSFuture $future) {
$headers = $this->getCanonicalHeaderMap($future);
$canonical_headers = array();
foreach ($headers as $header => $header_value) {
$canonical_headers[] = $header.':'.trim($header_value);
}
return implode("\n", $canonical_headers);
}
private function getCanonicalHeaderMap(HTTPSFuture $future) {
$headers = $future->getHeaders();
$headers[] = array(
'Host',
$this->getHost($future),
);
$header_map = array();
foreach ($headers as $header) {
list($key, $value) = $header;
$key = phutil_utf8_strtolower($key);
$header_map[$key] = $value;
}
ksort($header_map);
return $header_map;
}
private function getSignedHeaderList(HTTPSFuture $future) {
$headers = $this->getCanonicalHeaderMap($future);
return implode(';', array_keys($headers));
}
private function getCanonicalParameterList(HTTPSFuture $future) {
$uri = new PhutilURI($future->getURI());
$params = $uri->getQueryParams();
ksort($params);
$canonical_parameters = array();
foreach ($params as $key => $value) {
$canonical_parameters[] = rawurlencode($key).'='.rawurlencode($value);
}
$canonical_parameters = implode('&', $canonical_parameters);
return $canonical_parameters;
}
private function getCredential() {
$access_key = $this->accessKey;
if (!strlen($access_key)) {
throw new PhutilInvalidStateException('setAccessKey');
}
$parts = $this->getScopeParts();
array_unshift($parts, $access_key);
return implode('/', $parts);
}
}
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