What are the default permissions for "self-signed" applets?

Question

Hello!
I have a self-signed applet (=signed with a self made certificate) and under most plugin-enviroments java asks the user if it accepts this certificate as trustworth.
On my linux-box I do not have any problems to write files to the local filesystem after I accepted this self-signed applet.
However I've often read that users must grant some permissions even for signed applets, so is there a list of permissions that are denied by default?
Are there differences between java releases starting with 1.2.2?
Thanks in advance, lg Clemens

Answer 1

Default settings are like you said, jre asks the user and everything will work.
Unless.your applet uses classes that are not signed like with calls from javascript to your applet the plugin.jar is used and you'll get an exception when writing to files.
When writing to files the OS might not allowe the user to write to a certain file or folder.
Don't know what type of exception will be thrown if the OS doesn't allowe it but it has
nothing to do with applet permissions.
To change the default setting you can add the following line in the grant { bit of the
java.policy
permission java.lang.RuntimePermission "usePolicy";
When this line is there all signatures will be ignored and an applet can only do extra
things (like access to local files) if a policy is set up for this applet.
To find out what's wrong at your clients site you should ask them to send a full trace
and check that. I hope you did a .printStacktrace() on the exception in your code so
you can see if any other classes are involved when the exception is thrown.
To turn the full trace on (windows) you can start the java console, to be found here:
C:\Program Files\Java\j2re1.4...\bin\jpicpl32.exe
In the advanced tab you can fill in something for runtime parameters fill in this:
-Djavaplugin.trace=true -Djavaplugin.trace.option=basic|net|security|ext|liveconnect
if you cannot start the java console check here:
C:\Documents and Settings\userName\Application Data\Sun\Java\Deployment\deployment.properties
I think for linux this is somewhere in youruserdir/java (hidden directory)
add or change the following line:
javaplugin.jre.params=-Djavaplugin.trace\=true -Djavaplugin.trace.option\=basic|net|security|ext|liveconnect
for 1.5:
deployment.javapi.jre.1.5.0.args=-Djavaplugin.trace\=true -Djavaplugin.trace.option\=basic|net|security|ext|liveconnect
The trace is here:
C:\Documents and Settings\your user\Application Data\Sun\Java\Deployment\log\plugin...log
I think for linux this is somewhere in youruserdir/java (hidden directory)