Viewing file:  SignatureV4.php (19.55 KB) -rw-r--r--
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<?php
namespace Aws\Signature;
use Aws\Credentials\CredentialsInterface;
use AWS\CRT\Auth\Signable;
use AWS\CRT\Auth\SignatureType;
use AWS\CRT\Auth\SignedBodyHeaderType;
use AWS\CRT\Auth\Signing;
use AWS\CRT\Auth\SigningAlgorithm;
use AWS\CRT\Auth\SigningConfigAWS;
use AWS\CRT\Auth\StaticCredentialsProvider;
use AWS\CRT\HTTP\Request;
use Aws\Exception\CommonRuntimeException;
use Aws\Exception\CouldNotCreateChecksumException;
use GuzzleHttp\Psr7;
use Psr\Http\Message\RequestInterface;
/**
* Signature Version 4
* @link http://docs.aws.amazon.com/general/latest/gr/signature-version-4.html
*/
class SignatureV4 implements SignatureInterface
{
use SignatureTrait;
const ISO8601_BASIC = 'Ymd\THis\Z';
const UNSIGNED_PAYLOAD = 'UNSIGNED-PAYLOAD';
const AMZ_CONTENT_SHA256_HEADER = 'X-Amz-Content-Sha256';
/** @var string */
private $service;
/** @var string */
protected $region;
/** @var bool */
private $unsigned;
/** @var bool */
private $useV4a;
/**
* The following headers are not signed because signing these headers
* would potentially cause a signature mismatch when sending a request
* through a proxy or if modified at the HTTP client level.
*
* @return array
*/
protected function getHeaderBlacklist()
{
return [
'cache-control' => true,
'content-type' => true,
'content-length' => true,
'expect' => true,
'max-forwards' => true,
'pragma' => true,
'range' => true,
'te' => true,
'if-match' => true,
'if-none-match' => true,
'if-modified-since' => true,
'if-unmodified-since' => true,
'if-range' => true,
'accept' => true,
'authorization' => true,
'proxy-authorization' => true,
'from' => true,
'referer' => true,
'user-agent' => true,
'X-Amz-User-Agent' => true,
'x-amzn-trace-id' => true,
'aws-sdk-invocation-id' => true,
'aws-sdk-retry' => true,
];
}
/**
* @param string $service Service name to use when signing
* @param string $region Region name to use when signing
* @param array $options Array of configuration options used when signing
* - unsigned-body: Flag to make request have unsigned payload.
* Unsigned body is used primarily for streaming requests.
*/
public function __construct($service, $region, array $options = [])
{
$this->service = $service;
$this->region = $region;
$this->unsigned = isset($options['unsigned-body']) ? $options['unsigned-body'] : false;
$this->useV4a = isset($options['use_v4a']) && $options['use_v4a'] === true;
}
/**
* {@inheritdoc}
*/
public function signRequest(
RequestInterface $request,
CredentialsInterface $credentials,
$signingService = null
) {
$ldt = gmdate(self::ISO8601_BASIC);
$sdt = substr($ldt, 0, 8);
$parsed = $this->parseRequest($request);
$parsed['headers']['X-Amz-Date'] = [$ldt];
if ($token = $credentials->getSecurityToken()) {
$parsed['headers']['X-Amz-Security-Token'] = [$token];
}
$service = isset($signingService) ? $signingService : $this->service;
if ($this->useV4a) {
return $this->signWithV4a($credentials, $request, $service);
}
$cs = $this->createScope($sdt, $this->region, $service);
$payload = $this->getPayload($request);
if ($payload == self::UNSIGNED_PAYLOAD) {
$parsed['headers'][self::AMZ_CONTENT_SHA256_HEADER] = [$payload];
}
$context = $this->createContext($parsed, $payload);
$toSign = $this->createStringToSign($ldt, $cs, $context['creq']);
$signingKey = $this->getSigningKey(
$sdt,
$this->region,
$service,
$credentials->getSecretKey()
);
$signature = hash_hmac('sha256', $toSign, $signingKey);
$parsed['headers']['Authorization'] = [
"AWS4-HMAC-SHA256 "
. "Credential={$credentials->getAccessKeyId()}/{$cs}, "
. "SignedHeaders={$context['headers']}, Signature={$signature}"
];
return $this->buildRequest($parsed);
}
/**
* Get the headers that were used to pre-sign the request.
* Used for the X-Amz-SignedHeaders header.
*
* @param array $headers
* @return array
*/
private function getPresignHeaders(array $headers)
{
$presignHeaders = [];
$blacklist = $this->getHeaderBlacklist();
foreach ($headers as $name => $value) {
$lName = strtolower($name);
if (!isset($blacklist[$lName])
&& $name !== self::AMZ_CONTENT_SHA256_HEADER
) {
$presignHeaders[] = $lName;
}
}
return $presignHeaders;
}
/**
* {@inheritdoc}
*/
public function presign(
RequestInterface $request,
CredentialsInterface $credentials,
$expires,
array $options = []
) {
$startTimestamp = isset($options['start_time'])
? $this->convertToTimestamp($options['start_time'], null)
: time();
$expiresTimestamp = $this->convertToTimestamp($expires, $startTimestamp);
if ($this->useV4a) {
return $this->presignWithV4a(
$request,
$credentials,
$this->convertExpires($expiresTimestamp, $startTimestamp)
);
}
$parsed = $this->createPresignedRequest($request, $credentials);
$payload = $this->getPresignedPayload($request);
$httpDate = gmdate(self::ISO8601_BASIC, $startTimestamp);
$shortDate = substr($httpDate, 0, 8);
$scope = $this->createScope($shortDate, $this->region, $this->service);
$credential = $credentials->getAccessKeyId() . '/' . $scope;
if ($credentials->getSecurityToken()) {
unset($parsed['headers']['X-Amz-Security-Token']);
}
$parsed['query']['X-Amz-Algorithm'] = 'AWS4-HMAC-SHA256';
$parsed['query']['X-Amz-Credential'] = $credential;
$parsed['query']['X-Amz-Date'] = gmdate('Ymd\THis\Z', $startTimestamp);
$parsed['query']['X-Amz-SignedHeaders'] = implode(';', $this->getPresignHeaders($parsed['headers']));
$parsed['query']['X-Amz-Expires'] = $this->convertExpires($expiresTimestamp, $startTimestamp);
$context = $this->createContext($parsed, $payload);
$stringToSign = $this->createStringToSign($httpDate, $scope, $context['creq']);
$key = $this->getSigningKey(
$shortDate,
$this->region,
$this->service,
$credentials->getSecretKey()
);
$parsed['query']['X-Amz-Signature'] = hash_hmac('sha256', $stringToSign, $key);
return $this->buildRequest($parsed);
}
/**
* Converts a POST request to a GET request by moving POST fields into the
* query string.
*
* Useful for pre-signing query protocol requests.
*
* @param RequestInterface $request Request to clone
*
* @return RequestInterface
* @throws \InvalidArgumentException if the method is not POST
*/
public static function convertPostToGet(RequestInterface $request, $additionalQueryParams = "")
{
if ($request->getMethod() !== 'POST') {
throw new \InvalidArgumentException('Expected a POST request but '
. 'received a ' . $request->getMethod() . ' request.');
}
$sr = $request->withMethod('GET')
->withBody(Psr7\Utils::streamFor(''))
->withoutHeader('Content-Type')
->withoutHeader('Content-Length');
// Move POST fields to the query if they are present
if ($request->getHeaderLine('Content-Type') === 'application/x-www-form-urlencoded') {
$body = (string) $request->getBody() . $additionalQueryParams;
$sr = $sr->withUri($sr->getUri()->withQuery($body));
}
return $sr;
}
protected function getPayload(RequestInterface $request)
{
if ($this->unsigned && $request->getUri()->getScheme() == 'https') {
return self::UNSIGNED_PAYLOAD;
}
// Calculate the request signature payload
if ($request->hasHeader(self::AMZ_CONTENT_SHA256_HEADER)) {
// Handle streaming operations (e.g. Glacier.UploadArchive)
return $request->getHeaderLine(self::AMZ_CONTENT_SHA256_HEADER);
}
if (!$request->getBody()->isSeekable()) {
throw new CouldNotCreateChecksumException('sha256');
}
try {
return Psr7\Utils::hash($request->getBody(), 'sha256');
} catch (\Exception $e) {
throw new CouldNotCreateChecksumException('sha256', $e);
}
}
protected function getPresignedPayload(RequestInterface $request)
{
return $this->getPayload($request);
}
protected function createCanonicalizedPath($path)
{
$doubleEncoded = rawurlencode(ltrim($path, '/'));
return '/' . str_replace('%2F', '/', $doubleEncoded);
}
private function createStringToSign($longDate, $credentialScope, $creq)
{
$hash = hash('sha256', $creq);
return "AWS4-HMAC-SHA256\n{$longDate}\n{$credentialScope}\n{$hash}";
}
private function createPresignedRequest(
RequestInterface $request,
CredentialsInterface $credentials
) {
$parsedRequest = $this->parseRequest($request);
// Make sure to handle temporary credentials
if ($token = $credentials->getSecurityToken()) {
$parsedRequest['headers']['X-Amz-Security-Token'] = [$token];
}
return $this->moveHeadersToQuery($parsedRequest);
}
/**
* @param array $parsedRequest
* @param string $payload Hash of the request payload
* @return array Returns an array of context information
*/
private function createContext(array $parsedRequest, $payload)
{
$blacklist = $this->getHeaderBlacklist();
// Normalize the path as required by SigV4
$canon = $parsedRequest['method'] . "\n"
. $this->createCanonicalizedPath($parsedRequest['path']) . "\n"
. $this->getCanonicalizedQuery($parsedRequest['query']) . "\n";
// Case-insensitively aggregate all of the headers.
$aggregate = [];
foreach ($parsedRequest['headers'] as $key => $values) {
$key = strtolower($key);
if (!isset($blacklist[$key])) {
foreach ($values as $v) {
$aggregate[$key][] = $v;
}
}
}
ksort($aggregate);
$canonHeaders = [];
foreach ($aggregate as $k => $v) {
if (count($v) > 0) {
sort($v);
}
$canonHeaders[] = $k . ':' . preg_replace('/\s+/', ' ', implode(',', $v));
}
$signedHeadersString = implode(';', array_keys($aggregate));
$canon .= implode("\n", $canonHeaders) . "\n\n"
. $signedHeadersString . "\n"
. $payload;
return ['creq' => $canon, 'headers' => $signedHeadersString];
}
private function getCanonicalizedQuery(array $query)
{
unset($query['X-Amz-Signature']);
if (!$query) {
return '';
}
$qs = '';
ksort($query);
foreach ($query as $k => $v) {
if (!is_array($v)) {
$qs .= rawurlencode($k) . '=' . rawurlencode($v !== null ? $v : '') . '&';
} else {
sort($v);
foreach ($v as $value) {
$qs .= rawurlencode($k) . '=' . rawurlencode($value !== null ? $value : '') . '&';
}
}
}
return substr($qs, 0, -1);
}
private function convertToTimestamp($dateValue, $relativeTimeBase = null)
{
if ($dateValue instanceof \DateTimeInterface) {
$timestamp = $dateValue->getTimestamp();
} elseif (!is_numeric($dateValue)) {
$timestamp = strtotime($dateValue,
$relativeTimeBase === null ? time() : $relativeTimeBase
);
} else {
$timestamp = $dateValue;
}
return $timestamp;
}
private function convertExpires($expiresTimestamp, $startTimestamp)
{
$duration = $expiresTimestamp - $startTimestamp;
// Ensure that the duration of the signature is not longer than a week
if ($duration > 604800) {
throw new \InvalidArgumentException('The expiration date of a '
. 'signature version 4 presigned URL must be less than one '
. 'week');
}
return $duration;
}
private function moveHeadersToQuery(array $parsedRequest)
{
//x-amz-user-agent shouldn't be put in a query param
unset($parsedRequest['headers']['X-Amz-User-Agent']);
foreach ($parsedRequest['headers'] as $name => $header) {
$lname = strtolower($name);
if (substr($lname, 0, 5) == 'x-amz') {
$parsedRequest['query'][$name] = $header;
}
$blacklist = $this->getHeaderBlacklist();
if (isset($blacklist[$lname])
|| $lname === strtolower(self::AMZ_CONTENT_SHA256_HEADER)
) {
unset($parsedRequest['headers'][$name]);
}
}
return $parsedRequest;
}
private function parseRequest(RequestInterface $request)
{
// Clean up any previously set headers.
/** @var RequestInterface $request */
$request = $request
->withoutHeader('X-Amz-Date')
->withoutHeader('Date')
->withoutHeader('Authorization');
$uri = $request->getUri();
return [
'method' => $request->getMethod(),
'path' => $uri->getPath(),
'query' => Psr7\Query::parse($uri->getQuery()),
'uri' => $uri,
'headers' => $request->getHeaders(),
'body' => $request->getBody(),
'version' => $request->getProtocolVersion()
];
}
private function buildRequest(array $req)
{
if ($req['query']) {
$req['uri'] = $req['uri']->withQuery(Psr7\Query::build($req['query']));
}
return new Psr7\Request(
$req['method'],
$req['uri'],
$req['headers'],
$req['body'],
$req['version']
);
}
protected function verifyCRTLoaded()
{
if (!extension_loaded('awscrt')) {
throw new CommonRuntimeException(
"AWS Common Runtime for PHP is required to use Signature V4A"
. ". Please install it using the instructions found at"
. " https://github.com/aws/aws-sdk-php/blob/master/CRT_INSTRUCTIONS.md"
);
}
}
protected function createCRTStaticCredentialsProvider($credentials)
{
return new StaticCredentialsProvider([
'access_key_id' => $credentials->getAccessKeyId(),
'secret_access_key' => $credentials->getSecretKey(),
'session_token' => $credentials->getSecurityToken(),
]);
}
private function removeIllegalV4aHeaders(&$request)
{
$illegalV4aHeaders = [
self::AMZ_CONTENT_SHA256_HEADER,
"aws-sdk-invocation-id",
"aws-sdk-retry",
'x-amz-region-set',
];
$storedHeaders = [];
foreach ($illegalV4aHeaders as $header) {
if ($request->hasHeader($header)){
$storedHeaders[$header] = $request->getHeader($header);
$request = $request->withoutHeader($header);
}
}
return $storedHeaders;
}
private function CRTRequestFromGuzzleRequest($request)
{
return new Request(
$request->getMethod(),
(string) $request->getUri(),
[], //leave empty as the query is parsed from the uri object
array_map(function ($header) {return $header[0];}, $request->getHeaders())
);
}
/**
* @param CredentialsInterface $credentials
* @param RequestInterface $request
* @param $signingService
* @param SigningConfigAWS|null $signingConfig
* @return RequestInterface
*/
protected function signWithV4a(
CredentialsInterface $credentials,
RequestInterface $request,
$signingService,
SigningConfigAWS $signingConfig = null
){
$this->verifyCRTLoaded();
$signingConfig = $signingConfig ?? new SigningConfigAWS([
'algorithm' => SigningAlgorithm::SIGv4_ASYMMETRIC,
'signature_type' => SignatureType::HTTP_REQUEST_HEADERS,
'credentials_provider' => $this->createCRTStaticCredentialsProvider($credentials),
'signed_body_value' => $this->getPayload($request),
'should_normalize_uri_path' => true,
'use_double_uri_encode' => true,
'region' => "*",
'service' => $signingService,
'date' => time(),
]);
$removedIllegalHeaders = $this->removeIllegalV4aHeaders($request);
$http_request = $this->CRTRequestFromGuzzleRequest($request);
Signing::signRequestAws(
Signable::fromHttpRequest($http_request),
$signingConfig, function ($signing_result, $error_code) use (&$http_request) {
$signing_result->applyToHttpRequest($http_request);
});
foreach ($removedIllegalHeaders as $header => $value) {
$request = $request->withHeader($header, $value);
}
$sigV4AHeaders = $http_request->headers();
foreach ($sigV4AHeaders->toArray() as $h => $v) {
$request = $request->withHeader($h, $v);
}
return $request;
}
protected function presignWithV4a(
RequestInterface $request,
CredentialsInterface $credentials,
$expires
)
{
$this->verifyCRTLoaded();
$credentials_provider = $this->createCRTStaticCredentialsProvider($credentials);
$signingConfig = new SigningConfigAWS([
'algorithm' => SigningAlgorithm::SIGv4_ASYMMETRIC,
'signature_type' => SignatureType::HTTP_REQUEST_QUERY_PARAMS,
'credentials_provider' => $credentials_provider,
'signed_body_value' => $this->getPresignedPayload($request),
'region' => "*",
'service' => $this->service,
'date' => time(),
'expiration_in_seconds' => $expires
]);
$this->removeIllegalV4aHeaders($request);
foreach ($this->getHeaderBlacklist() as $headerName => $headerValue) {
if ($request->hasHeader($headerName)) {
$request = $request->withoutHeader($headerName);
}
}
$http_request = $this->CRTRequestFromGuzzleRequest($request);
Signing::signRequestAws(
Signable::fromHttpRequest($http_request),
$signingConfig, function ($signing_result, $error_code) use (&$http_request) {
$signing_result->applyToHttpRequest($http_request);
});
return $request->withUri(
new Psr7\Uri($http_request->pathAndQuery())
);
}
}
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