8196830: publicLookup().findVirtual should not return method handle to AccessibleObject.setAccessible

Paul Sandoz paul.sandoz at oracle.com
Tue Feb 20 19:31:11 UTC 2018

Looks good, especially the test.


> On Feb 20, 2018, at 10:21 AM, mandy chung <mandy.chung at oracle.com> wrote:
> This patch looks good.  It's unfortunate that setAccessible was not final
> to begin with.  I agree that this fix is a good compromise with a simple
> fix and low incompatibility.   Is there a CSR to review?
> Mandy
> On 2/19/18 8:57 AM, Alan Bateman wrote:
>> > AccessibleObject's setAccessible(boolean) is currently not caller > 
> sensitive but the overrides in Method/Field/Constructor are. This > awkwardness stems from its constructor being protected and the method > not being final. It is thus possible to extend the class outside of > the java.lang.reflect package and override this method (at least one > popular library does this). Ideally the constructor should have been > package private and/or the method be final but it's not possible to > change this after 20 years. > > The consequence of the method in the base class not being caller > sensitive is that it's possible to use a minimally trusted lookup to > get a method handle to the method. Paul, Mandy and I chatted about > this one recently. We prototyped changes to the MH implementation to > special case this method and treat it "as if" it is caller sensitive. > This maximizes compatibility but has the downside that it makes it > harder to audit and somewhat fragile. In the end, we concluded it > would be simpler to add the @CS annotation to this method so that it > is treated consistently. The downside of this is that custom > AccessibleObject implementations need to override setAccessible if > they want to be invoked using method handles obtained from a > minimally trusted lookup. > > The proposed changes are simple. The removal of "checkMemberAccess" > from canBeCalledVirtual is just a clean-up because this method is no > longer needs special casing (it was degraded for Java SE 10 as > envisaged in JEP 176). It's not the goal here to improve the > performance of canBeCalledVirtual but there may be opportunities to > look at that with a separate issue: > http://cr.openjdk.java.net/~alanb/8196830/webrev/ > > -Alan

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