RFR (S): 8202650: Enforce group for attach listener file

[Langer, Christoph]

Hi Chris,

thanks for reviewing and offering to test, I appreciate that. As Thomas has reviewed it as well, could you please conduct your testing? I ran it through our local testing and jdk-submit, no regressions observed.

Thanks & Best regards
Christoph

> -----Original Message-----
> From: Chris Plummer [mailto:chris.plummer at oracle.com]
> Sent: Montag, 7. Mai 2018 20:30
> To: Langer, Christoph <christoph.langer at sap.com>; serviceability-
> dev at openjdk.java.net
> Cc: ppc-aix-port-dev at openjdk.java.net; Martin Buchholz
> <martinrb at google.com>
> Subject: Re: RFR (S): 8202650: Enforce group for attach listener file
> 
> Hi Christoph,
> 
> The changes look fine. There are some closed aod tests that should be
> run. I can do this for you once the review is done.
> 
> thank,s
> 
> Chris
> 
> On 5/6/18 12:23 PM, Langer, Christoph wrote:
> > Hi,
> >
> > with that information and Martins links to the specs, I suggest to add the
> patch to linux as well. I played with the sgid functionality on Linux and it is the
> same as on AIX. So, if somebody configured the directory where the attach
> listener file is created with sgid, the file will belong to the wrong group.
> >
> > See my new webrev:
> http://cr.openjdk.java.net/~clanger/webrevs/8202650.1/
> >
> > Thanks
> > Christoph
> >
> >> -----Original Message-----
> >> From: Chris Plummer [mailto:chris.plummer at oracle.com]
> >> Sent: Freitag, 4. Mai 2018 23:34
> >> To: Langer, Christoph <christoph.langer at sap.com>; serviceability-
> >> dev at openjdk.java.net
> >> Cc: ppc-aix-port-dev at openjdk.java.net
> >> Subject: Re: RFR (S): 8202650: Enforce group for attach listener file
> >>
> >> Hi Christoph,
> >>
> >> It looks like for bsd this code was added to fix JDK-7152800. In that CR
> >> I see the following:
> >>
> >> "The attach framework will verify that the file has the same effective
> >> owner and group as the currently running process. This will be true on
> >> linux, since files are created with the effective user and group as
> >> owner. This will NOT be true always on macos, since the file can have a
> >> different group if the temporary directory has a different group than
> >> what we are currently running as."
> >>
> >> So it looks like the fix is not necessary for Linux. It wouldn't hurt to
> >> experiment by setting the s-bit on the directory and see if you have the
> >> same problem as macos and AIX.
> >>
> >> thanks,
> >>
> >> Chris
> >>
> >> On 5/4/18 7:29 AM, Langer, Christoph wrote:
> >>> Hi,
> >>>
> >>> please review a change for correctly setting the group for the attach
> >>> listener file:
> >>>
> >>> Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8202650.0/
> >>> <http://cr.openjdk.java.net/%7Eclanger/webrevs/8202650.0/>
> >>>
> >>> Bug: https://bugs.openjdk.java.net/browse/JDK-8202650
> >>> <https://bugs.openjdk.java.net/browse/JDK-8202650>
> >>>
> >>> The attach listener file, usually /tmp/.java_pid<pid> is created from
> >>> the hotspot JVM process. Usually it will belong to the process user
> >>> and group. However, when the directory where it is created has set the
> >>> s-bit for groups, the group of the directory is taken. This will cause
> >>> errors when the attach client tries to connect and it is checked
> >>> whether the group of the attach file matches the client processes'
> group.
> >>>
> >>> In my webrev I only implemented the change for AIX because we have
> run
> >>> into an issue on that platform. But I can see this code already in
> >>> place for attachListener_bsd.cpp. And I’m wondering if this should
> >>> also be added to attachListener_linux.cpp because the sticky-bit could
> >>> be set with the same effects on Linux, too. Any opinions about that?
> >>>
> >>> Thanks and best regards
> >>>
> >>> Christoph
> >>>
>