From 37f85034422ce86438d52ab5d86f4d675689c8ff Mon Sep 17 00:00:00 2001
From: Joakim Erdfelt <joakim.erdfelt@gmail.com>
Date: Wed, 15 Jan 2020 15:31:43 -0600
Subject: [PATCH] Issue #4383 - Minimal NPE prevention on MultiPart

Signed-off-by: Joakim Erdfelt <joakim.erdfelt@gmail.com>
---
 .../jetty/http/MultiPartFormInputStream.java       |  7 +++++++
 .../jetty/http/MultiPartFormInputStreamTest.java   | 14 ++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormInputStream.java b/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormInputStream.java
index 05c1dbf25e17..08f1e0b96e6e 100644
--- a/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormInputStream.java
+++ b/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormInputStream.java
@@ -397,6 +397,13 @@ public Collection<Part> getParsedParts()
      */
     public void deleteParts()
     {
+        if (_parts == null)
+        {
+            // If we call deleteParts at this point, we are considered CLOSED
+            _err = new IllegalStateException("CLOSED via call to deleteParts()");
+            return;
+        }
+
         MultiException err = null;
         for (List<Part> parts : _parts.values())
         {
diff --git a/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormInputStreamTest.java b/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormInputStreamTest.java
index 2308314886cd..2e7062c4c631 100644
--- a/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormInputStreamTest.java
+++ b/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormInputStreamTest.java
@@ -509,6 +509,20 @@ public void testPartTmpFileDeletion() throws Exception
         assertThat(stuff.exists(), is(false));  //tmp file was removed after cleanup
     }
 
+    @Test
+    public void testParseAfterCleanUp() throws Exception
+    {
+        final InputStream input = new ByteArrayInputStream(createMultipartRequestString("myFile").getBytes());
+        MultipartConfigElement config = new MultipartConfigElement(_dirname, 1024, 1024, 50);
+        MultiPartFormInputStream mpis = new MultiPartFormInputStream(input, _contentType, config, _tmpDir);
+
+        mpis.deleteParts();
+
+        // The call to getParts should throw because we have already cleaned up the parts.
+        Throwable error = assertThrows(IllegalStateException.class, mpis::getParts);
+        assertThat(error.getMessage(), containsString("CLOSED"));
+    }
+
     @Test
     public void testLFOnlyRequest()
         throws Exception