JEP Review Request: Improve Security Manager Performance

[David M. Lloyd]

On 04/25/2014 09:36 AM, Sean Mullan wrote:
> Please review a draft of a proposed research JEP to improve the
> performance of the Security Manager:

I have another idea that might be worth looking into.  One problem with 
security manager performance is that many times a class will perform 
privileged actions in the static initializer block.  This is because 
static class initialization runs with whatever security context is 
active when that class happens to be initialized - it's essentially 
random as far as most developers are concerned, and even the experts 
cannot always correctly predict how initialization happens (see: last 
several years of java.util.logging class init debacle).

This causes performance (and usability) problems because:

• Static init blocks can, for most practical purposes, never rely on 
their caller, so they must always perform privileged actions within 
doPrivileged
• This also results in another class to load and initialize
• Often, there is more than one data item needed from the privileged 
block, requiring either multiple doPrivileged calls (slow) or using 
hackery like returning an Object[] array out of the block

I would suggest that one or more of the following be done to mitigate 
this problem:

• Always have static initialization blocks be privileged (this does 
require users to be cognizant of this fact when writing static blocks)
• Allow static initialization blocks to partake in the aforementioned 
annotation-driven privileged method idea
• Introduce a new permission checking mechanism which examines only a 
specific relevant caller's protection domain (perhaps determined by 
filter expression, possibly using the stack examination scheme that 
Mandy Chung has been working on)
• Introduce a programmatic "elevation" mechanism that increases the 
privileges of the currently executing method for the remainder of its 
execution without requiring a call-in to doPrivileged or instantiation 
of a privileged action object

-- 
- DML