Hi, On 4/8/07, Robert Lougher <rob.lougher@xxxxxxxxx> wrote:
Hi Mark, On 4/8/07, Mark Wielaard <mark@xxxxxxxxx> wrote: > On Sun, 2007-04-08 at 12:53 +0200, Christian Thalinger wrote: > > Grrr, I hate this access checks. I'll try to fix that _again_. > > This seems to be pretty subtle and we found multiple runtimes (jamvm, > cacao, gcj and kaffe at least) that seem to get this wrong. ... > So when Method.invoke() is called on an method member of an object which > class type isn't public then it should only be allowed to successfully > call the method if the caller is in the same package. > Strangely enough, I _did_ fix this in JamVM 1.4.4, but then removed the checks again in JamVM 1.4.5! http://cvs.berlios.de/cgi-bin/viewcvs.cgi/jamvm/jamvm/src/reflect.c.diff?r1=1.9&r2=1.10 If I remember the reason for removing it again was that it broke some stuff. I had a quick look at cacao and gcj, and found they didn't do the check, and not having the time at that point to look into it properly just backed the change out. I'll see if I can find what broke.
Yes, answering my own post :) Anyway, I've found what it broke and my original analysis. After putting this in, BeanShell GUI stopped working with JamVM. This was found during 0.93 testing: http://www.mail-archive.com/classpath@xxxxxxx/msg13811.html I did an original analysis, where I tracked it down to the extra reflection checks. Of course, I could have been wrong, and I've not rechecked this. At the time I just decided to remove the checks... Date: Thu, 7 Dec 2006 02:16:44 +0000 From: "Robert Lougher" <rob.lougher@xxxxxxxxx> To: "Mark Wielaard" <mark@xxxxxxxxx> Subject: Re: Re: 0.93 branch created In-Reply-To: <1165274185.3061.46.camel@xxxxxxxxxxxxxxxxxxxxxxx> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_25035_17595680.1165457804811" References: <1165024599.3054.80.camel@xxxxxxxxxxxxxxxxxxxxxxx> <1165263663.28379.4.camel@localhost> <1165274185.3061.46.camel@xxxxxxxxxxxxxxxxxxxxxxx> Delivered-To: rob.lougher@xxxxxxxxx ------=_Part_25035_17595680.1165457804811 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Hi Mark, I've spent some time looking at this.
From what I can see, there's an attempt to invoke via reflection the
method "getValue" on an Object of type "java.util.Hashtable$HashEntry". The invoke is from class "bsh.Reflect". The method "getValue" is defined in class "java.util.AbstractMap$BasicMapEntry". The problem is that although method "getValue" is public, the class "java.util.AbstractMap$BasicMapEntry" is package-private. When JamVM does a method invoke, it checks that the class that defined the method is accessible, and given that, that the method is also accessible. The class access check fails, and an IllegalAccessException is thrown, which is converted to the UndeclaredThrowableException. The reason that Cacao works is that its reflection code does not do the class access check. If I remove the class access check in JamVM the UndeclaredThrowableException no longer gets thrown. The reason I put the class access check in is to fix some reflection tests. The attached simple reflection test throws an IllegalAccessException on both JamVM and Suns VM (to run do jamvm/java test). If I remove the class access check, the method invoke wrongly succeeds. I don't know where the problem lies. The class "java.util.Hashtable$HashEntry" is private, so I don't know if bsh.Reflect should have a reference anyway. Anyway, I can't do any more investigation tonight, as it's late! Thanks, Rob.
