core: correcting a minor resource releasing issue

rturner-edjuster · web-flow · commit b9becb5c8e79 · 2021-07-15T17:08:00.000-07:00
This change adds a traditional try/finally block around readers and
streams to control the closing of those objects when the method has
completed rather than relying on the GC to deal with them.

This issue was flagged by an analysis tool via binary analysis of the
grpc-core package as part of a dependency from another project.
diff --git a/core/src/main/java/io/grpc/util/CertificateUtils.java b/core/src/main/java/io/grpc/util/CertificateUtils.java
@@ -65,24 +65,36 @@ public static X509Certificate[] getX509Certificates(InputStream inputStream)
   public static PrivateKey getPrivateKey(InputStream inputStream)
       throws UnsupportedEncodingException, IOException, NoSuchAlgorithmException,
       InvalidKeySpecException {
-    BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));
-    String line;
-    while ((line = reader.readLine()) != null) {
-      if ("-----BEGIN PRIVATE KEY-----".equals(line)) {
-        break;
+    InputStreamReader isr = null;
+    BufferedReader reader = null;
+    try {
+      isr = new InputStreamReader(inputStream, "UTF-8");
+      reader = new BufferedReader(isr);
+      String line;
+      while ((line = reader.readLine()) != null) {
+        if ("-----BEGIN PRIVATE KEY-----".equals(line)) {
+          break;
+        }
       }
-    }
-    StringBuilder keyContent = new StringBuilder();
-    while ((line = reader.readLine()) != null) {
-      if ("-----END PRIVATE KEY-----".equals(line)) {
-        break;
+      StringBuilder keyContent = new StringBuilder();
+      while ((line = reader.readLine()) != null) {
+        if ("-----END PRIVATE KEY-----".equals(line)) {
+          break;
+        }
+        keyContent.append(line);
+      }
+      byte[] decodedKeyBytes = BaseEncoding.base64().decode(keyContent.toString());
+      KeyFactory keyFactory = KeyFactory.getInstance("RSA");
+      PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(decodedKeyBytes);
+      return keyFactory.generatePrivate(keySpec);
+    } finally {
+      if (null != reader) {
+        reader.close();
+      }
+      if (null != isr) {
+        isr.close();
       }
-      keyContent.append(line);
     }
-    byte[] decodedKeyBytes = BaseEncoding.base64().decode(keyContent.toString());
-    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
-    PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(decodedKeyBytes);
-    return keyFactory.generatePrivate(keySpec);
   }
 }
 
