Fix BZ 64830 - concurrency issue in HPACK decoder

https://bz.apache.org/bugzilla/show_bug.cgi?id=64830
apache · Nov 9, 2020 · 8d2fe68 · 8d2fe68
1 parent 7f004ac
commit 8d2fe68
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 8 deletions.
diff --git a/java/org/apache/coyote/http2/HpackDecoder.java b/java/org/apache/coyote/http2/HpackDecoder.java
@@ -72,8 +72,6 @@ public class HpackDecoder {
     private volatile boolean countedCookie;
     private volatile int headerSize = 0;
 
-    private final StringBuilder stringBuilder = new StringBuilder();
-
     HpackDecoder(int maxMemorySize) {
         this.maxMemorySizeHard = maxMemorySize;
         this.maxMemorySizeSoft = maxMemorySize;
@@ -222,19 +220,17 @@ private String readHpackString(ByteBuffer buffer) throws HpackException {
         if (huffman) {
             return readHuffmanString(length, buffer);
         }
+        StringBuilder stringBuilder = new StringBuilder(length);
         for (int i = 0; i < length; ++i) {
             stringBuilder.append((char) buffer.get());
         }
-        String ret = stringBuilder.toString();
-        stringBuilder.setLength(0);
-        return ret;
+        return stringBuilder.toString();
     }
 
     private String readHuffmanString(int length, ByteBuffer buffer) throws HpackException {
+        StringBuilder stringBuilder = new StringBuilder(length);
         HPackHuffman.decode(buffer, length, stringBuilder);
-        String ret = stringBuilder.toString();
-        stringBuilder.setLength(0);
-        return ret;
+        return stringBuilder.toString();
     }
 
     private String handleIndexedHeaderName(int index) throws HpackException {

diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
@@ -132,6 +132,9 @@
         Add additional debug logging for I/O issues when communicating with the
         user agent. (markt)
       </add>
+      <fix>
+        <bug>64830</bug>: Fix concurrency issue in HPACK decoder. (markt)
+      </fix>
     </changelog>
   </subsection>
   <subsection name="Jasper">