Merge pull request from GHSA-95x4-j7vc-h8mf

Stop parsing multipart request bodies once the configured limit of form fields and files has been reached

Author: clue

src/Io/MultipartParser.php

@@ -26,6 +26,13 @@ final class MultipartParser
      */
     private $maxFileSize;
 
+    /**
+     * Based on $maxInputVars and $maxFileUploads
+     *
+     * @var int
+     */
+    private $maxMultipartBodyParts;
+
     /**
      * ini setting "max_input_vars"
      *
@@ -62,6 +69,7 @@ final class MultipartParser
      */
     private $maxFileUploads;
 
+    private $multipartBodyPartCount = 0;
     private $postCount = 0;
     private $filesCount = 0;
     private $emptyCount = 0;
@@ -87,6 +95,8 @@ public function __construct($uploadMaxFilesize = null, $maxFileUploads = null)
 
         $this->uploadMaxFilesize = IniUtil::iniSizeToBytes($uploadMaxFilesize);
         $this->maxFileUploads = $maxFileUploads === null ? (\ini_get('file_uploads') === '' ? 0 : (int)\ini_get('max_file_uploads')) : (int)$maxFileUploads;
+
+        $this->maxMultipartBodyParts = $this->maxInputVars + $this->maxFileUploads;
     }
 
     public function parse(ServerRequestInterface $request)
@@ -101,6 +111,7 @@ public function parse(ServerRequestInterface $request)
 
         $request = $this->request;
         $this->request = null;
+        $this->multipartBodyPartCount = 0;
         $this->postCount = 0;
         $this->filesCount = 0;
         $this->emptyCount = 0;
@@ -128,6 +139,10 @@ private function parseBody($boundary, $buffer)
             // parse one part and continue searching for next
             $this->parsePart(\substr($buffer, $start, $end - $start));
             $start = $end;
+
+            if (++$this->multipartBodyPartCount > $this->maxMultipartBodyParts) {
+                break;
+            }
         }
     }
 

tests/Io/MultipartParserTest.php

@@ -1026,4 +1026,29 @@ public function testPostMaxFileSizeIgnoredByFilesComingBeforeIt()
         $this->assertTrue(isset($files['file4']));
         $this->assertSame(UPLOAD_ERR_OK, $files['file4']->getError());
     }
-}
+
+    public function testWeOnlyParseTheAmountOfMultiPartChunksWeConfigured()
+    {
+        $boundary = "---------------------------12758086162038677464950549563";
+
+        $chunk = "--$boundary\r\n";
+        $chunk .= "Content-Disposition: form-data; name=\"f\"\r\n";
+        $chunk .= "\r\n";
+        $chunk .= "u\r\n";
+        $data = '';
+        for ($i = 0; $i < 5000000; $i++) {
+            $data .= $chunk;
+        }
+        $data .= "--$boundary--\r\n";
+
+        $request = new ServerRequest('POST', 'http://example.com/', array(
+            'Content-Type' => 'multipart/form-data; boundary=' . $boundary,
+        ), $data, 1.1);
+
+        $parser = new MultipartParser();
+        $startTime = microtime(true);
+        $parser->parse($request);
+        $runTime = microtime(true) - $startTime;
+        $this->assertLessThan(1, $runTime);
+    }
+}