Bug 66425: Avoid exceptions found via poi-fuzz

Prevent ClassCastException

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=63736

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1915003 13f79535-47bb-0310-9956-ffa450edef68

poi/src/main/java/org/apache/poi/poifs/crypt/agile/AgileEncryptionInfoBuilder.java

@@ -36,6 +36,10 @@ public class AgileEncryptionInfoBuilder implements EncryptionInfoBuilder {
 
     @Override
     public void initialize(EncryptionInfo info, LittleEndianInput dis) throws IOException {
+        if (!(dis instanceof InputStream)) {
+            throw new IllegalArgumentException("Had unexpected type of input: " + (dis == null ? "<null>" : dis.getClass()));
+        }
+
         EncryptionDocument ed = parseDescriptor((InputStream)dis);
         info.setHeader(new AgileEncryptionHeader(ed));
         info.setVerifier(new AgileEncryptionVerifier(ed));

poi/src/test/java/org/apache/poi/hssf/dev/BaseTestIteratingXLS.java

@@ -89,6 +89,7 @@ public abstract class BaseTestIteratingXLS {
         // fuzzed binaries
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-6322470200934400.xls", RuntimeException.class);
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-4819588401201152.xls", RuntimeException.class);
+        excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-6537773940867072.xls", RuntimeException.class);
         return excludes;
     }