Merge pull request #3 from google/pr/2

Merge dolph's file permission change, plus a commit to make it clearer.

java/code/src/org/keyczar/GenericKeyczar.java

@@ -296,7 +296,7 @@ void writeEncrypted(String location, Encrypter encrypter)
   }
 
   /**
-   * Utility function to write given data to a file at given location.
+   * Utility function to securely write given data to a file at given location.
    *
    * @param data String data to be written
    * @param location String pathname of destination file
@@ -307,6 +307,16 @@ void writeFile(String data, String location)
     File outputFile = new File(location);
     try {
       FileWriter writer = new FileWriter(outputFile);
+
+      // only allow the file owner to read/write the file
+      final boolean appliesToAll = false;
+      final boolean appliesToOwner = true;
+      outputFile.setReadable(false, appliesToAll);
+      outputFile.setReadable(true, appliesToOwner);
+      outputFile.setWritable(false, appliesToAll);
+      outputFile.setWritable(true, appliesToOwner);
+      outputFile.setExecutable(false, appliesToAll);
+
       writer.write(data);
       writer.close();
     } catch (IOException e) {

java/code/src/org/keyczar/KeyczarTool.java

@@ -304,8 +304,8 @@ private static RsaPadding getPadding(String paddingFlag) throws KeyczarException
 
   /**
    * Creates a new KeyMetadata object, deciding its name, purpose and type
-   * based on command line flags. Outputs its JSON representation in a file
-   * named meta in the directory given by the location flag.
+   * based on command line flags. Outputs its JSON representation in a secure
+   * file named meta in the directory given by the location flag.
    * @param asymmetricFlag
    * @param purposeFlag
    * @param nameFlag
@@ -367,6 +367,16 @@ private static void create(String locationFlag, String nameFlag,
       }
       try {
         FileOutputStream metaOutput = new FileOutputStream(file);
+
+        // only allow the file owner to read/write the file
+        final boolean appliesToAll = false;
+        final boolean appliesToOwner = true;
+        file.setReadable(false, appliesToAll);
+        file.setReadable(true, appliesToOwner);
+        file.setWritable(false, appliesToAll);
+        file.setWritable(true, appliesToOwner);
+        file.setExecutable(false, appliesToAll);
+
         metaOutput.write(kmd.toString().getBytes(Keyczar.DEFAULT_ENCODING));
         metaOutput.close();
       } catch (IOException e) {