Sanitize host name for AWS requests before signing in AWSAuthV4 transport (ruflin#2090)

Author: Jan Hübner

CHANGELOG.md

@@ -24,7 +24,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Updated `Query::create` PHPDoc to include supported types and propagate it to callers by @franmomu [#2088](https://github.com/ruflin/Elastica/pull/2088)
 * Update some iterable types in PHPDoc to be more specific by @franmomu [#2092](https://github.com/ruflin/Elastica/pull/2092)
 * Updated `AwsAuthV4Test` adding assertions for exception type by @franmomu [#2094](https://github.com/ruflin/Elastica/pull/2094)
-
+* Update `AWSAuthV4 transport` to sanitize host name for AWS requests before signing [#2090](https://github.com/ruflin/Elastica/pull/2090)
 ### Deprecated
 * Deprecated `Elastica\Reindex::WAIT_FOR_COMPLETION_FALSE`, use a boolean as parameter instead by @franmomu [#2070](https://github.com/ruflin/Elastica/pull/2070)
 * Passing anything else than a boolean as 1st argument to `Reindex::setWaitForCompletion`, pass a boolean instead by @franmomu [#2070](https://github.com/ruflin/Elastica/pull/2070)

phpstan-baseline.neon

@@ -135,3 +135,7 @@ parameters:
 			count: 1
 			path: tests/SnapshotTest.php
 
+		-
+			message: "#^Function GuzzleHttp\\\\Psr7\\\\modify_request not found\\.$#"
+			count: 1
+			path: src/Transport/AwsAuthV4.php

src/Transport/AwsAuthV4.php

@@ -10,6 +10,7 @@
 use GuzzleHttp\Client;
 use GuzzleHttp\HandlerStack;
 use GuzzleHttp\Middleware;
+use GuzzleHttp\Psr7;
 use Psr\Http\Message\RequestInterface;
 
 class AwsAuthV4 extends Guzzle
@@ -42,15 +43,33 @@ private function getSigningMiddleware(): callable
             : \getenv('AWS_REGION');
         $signer = new SignatureV4('es', $region);
         $credProvider = $this->getCredentialProvider();
+        $transport = $this;
 
         return Middleware::mapRequest(static function (RequestInterface $req) use (
             $signer,
-            $credProvider
+            $credProvider,
+            $transport
         ) {
-            return $signer->signRequest($req, $credProvider()->wait());
+            return $signer->signRequest($transport->sanitizeRequest($req), $credProvider()->wait());
         });
     }
 
+    private function sanitizeRequest(RequestInterface $request): RequestInterface
+    {
+        // Trailing dots are valid parts of DNS host names (see RFC 1034),
+        // but interferes with header signing where AWS expects a stripped host name.
+        if ('.' === \substr($request->getHeader('host')[0], -1)) {
+            $changes = ['set_headers' => ['host' => \rtrim($request->getHeader('host')[0], '.')]];
+            if (\class_exists(Psr7\Utils::class)) {
+                $request = Psr7\Utils::modifyRequest($request, $changes);
+            } else {
+                $request = Psr7\modify_request($request, $changes);
+            }
+        }
+
+        return $request;
+    }
+
     private function getCredentialProvider(): callable
     {
         $connection = $this->getConnection();

tests/Transport/AwsAuthV4Test.php

@@ -205,4 +205,35 @@ public function testSignsWithEnvironmentalCredentials(): void
             );
         }
     }
+
+    /**
+     * @group unit
+     * @depends testSignsWithProvidedCredentials
+     */
+    public function testStripsTrailingDotInHost(): void
+    {
+        $host = $this->_getHost();
+        $hostWithTrailingDot = $host.'.';
+
+        $config = [
+            'persistent' => false,
+            'transport' => 'AwsAuthV4',
+            'aws_access_key_id' => 'foo',
+            'aws_secret_access_key' => 'bar',
+            'aws_session_token' => 'baz',
+            'aws_region' => 'us-east-1',
+            'host' => $hostWithTrailingDot,
+        ];
+        $client = $this->_getClient($config);
+
+        try {
+            $client->request('_stats');
+        } catch (GuzzleException $e) {
+            $guzzleException = $e->getGuzzleException();
+            $this->assertInstanceOf(ConnectException::class, $guzzleException);
+            $request = $guzzleException->getRequest();
+            $this->assertSame($host, $request->getHeader('host')[0]);
+            $this->assertSame($hostWithTrailingDot, $request->getUri()->getHost());
+        }
+    }
 }