Port PGP utility fix from Java

Author: peterdettman

crypto/src/bcpg/BcpgOutputStream.cs

@@ -376,6 +376,7 @@ public void Finish()
             if (partialBuffer != null)
             {
                 PartialFlush(true);
+                Array.Clear(partialBuffer, 0, partialBuffer.Length);
                 partialBuffer = null;
             }
         }

crypto/src/bcpg/LiteralDataPacket.cs

@@ -23,7 +23,11 @@ internal LiteralDataPacket(
 			fileName = new byte[len];
 			for (int i = 0; i != len; ++i)
             {
-                fileName[i] = (byte)bcpgIn.ReadByte();
+                int ch = bcpgIn.ReadByte();
+                if (ch < 0)
+                    throw new IOException("literal data truncated in header");
+
+                fileName[i] = (byte)ch;
             }
 
 			modDate = (((uint)bcpgIn.ReadByte() << 24)

crypto/src/openpgp/PgpUtilities.cs

@@ -367,7 +367,7 @@ public static void WriteFileToLiteralData(
             byte[]		buffer)
         {
             PgpLiteralDataGenerator lData = new PgpLiteralDataGenerator();
-            Stream pOut = lData.Open(output, fileType, file.Name, file.LastWriteTime, buffer);
+            Stream pOut = lData.Open(output, fileType, file.Name, file.LastWriteTime, Arrays.Clone(buffer));
 			PipeFileContents(file, pOut, buffer.Length);
         }