Bug 66425: Avoid NullPointerExceptions found via poi-fuzz

We try to avoid throwing NullPointerException, but it was possible
to trigger one here

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1912281 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 6 insertions, 0 deletions

diff --git a/poi/src/main/java/org/apache/poi/poifs/crypt/CryptoFunctions.java b/poi/src/main/java/org/apache/poi/poifs/crypt/CryptoFunctions.java
index 587d72eca6..9a91165660 100644
--- a/poi/src/main/java/org/apache/poi/poifs/crypt/CryptoFunctions.java
+++ b/poi/src/main/java/org/apache/poi/poifs/crypt/CryptoFunctions.java
@@ -252,9 +252,15 @@ public final class CryptoFunctions {
             if (cipherAlgorithm == CipherAlgorithm.rc4) {
                 cipher = Cipher.getInstance(cipherAlgorithm.jceId);
             } else if (cipherAlgorithm.needsBouncyCastle) {
+                if (chain == null) {
+                    throw new IllegalArgumentException("Did not have a chain for cipher " + cipherAlgorithm);
+                }
                 registerBouncyCastle();
                 cipher = Cipher.getInstance(cipherAlgorithm.jceId + "/" + chain.jceId + "/" + padding, "BC");
             } else {
+                if (chain == null) {
+                    throw new IllegalArgumentException("Did not have a chain for cipher " + cipherAlgorithm);
+                }
                 cipher = Cipher.getInstance(cipherAlgorithm.jceId + "/" + chain.jceId + "/" + padding);
             }