On Thu, 13 Nov 2025 11:02:21 GMT, Nick Hall <[email protected]> wrote:
>> _Purpose_
>>
>> This PR allows Linux based applications using JAAS to acquire Kerberos TGTs
>> natively using the local system's Kerberos libraries/configuration, building
>> on existing support on Windows/MacOSX.
>>
>> _Rationale_
>>
>> Currently the (pure java) JAAS codebase only supports file-based credential
>> caches (ccaches). There are many other useful types of ccache accessible
>> via the local system libraries; this change allows credentials to be
>> acquired natively using those libraries, and thus adds support for all other
>> ccache types supported by the local system (e.g. KCM, in-memory and kernel
>> types), This support already exists on MacOSX and Windows.
>>
>> The code change here largely uses the MacOSX code, edited for Linux with
>> associated build system changes. It also adds an appropriate jtreg test
>> which uses some native test helper code to manufacture an in-memory cache,
>> and then uses the new code to acquire these credentials natively. This has
>> been tested on Linux/Mac and the jtreg test passes on each (I couldn't see
>> any existing tests on MacOSX for this feature).
>>
>> Additionally this PR fixes a bug that's existed for a while (see L585-588 in
>> `nativeccache.c`) - without this code, this is a 100% reproducible segfault
>> on Linux (it's unclear why this hasn't affected the Mac JVMs up to now,
>> probably just no calling code that provides an empty list of addresses). It
>> also fixes a (non problem) typo in the variable name in a function prototype.
>>
>> _Implementation Detail_
>>
>> Note that there were multiple possible ways of doing this:
>>
>> 1) Duplicate the MacOSX `nativeccache.c`, edit lightly for Linux and build a
>> new library on Linux only (`liblinuxkrb5`), leaving MacOSX largely
>> unchanged, but at the expense of this code duplication.
>>
>> 2) Create a new shared library used on both platforms with conditional
>> compilation to manage the differences. This necessitates a library name
>> change on MacOSX and potentially knock-on packaging changes on that
>> platform, which seemed a potentially expensive side-effect.
>>
>> 3) Create a shared `nativeccache.c` (using `EXTRA_SRC` in the build) and
>> build separate MacOSX/Linux libraries. This allows the MacOSX library name
>> to remain unchanged, and only adds a new library in Linux.
>>
>> I tried all three options; 3 seemed to be the best compromise all around,
>> although is one of the options that effectively introduces a "no-op" change
>> on MacOSX as a result. Hopefully the additional jtreg test is sufficient to
>> compensat...
>
> Nick Hall has updated the pull request incrementally with three additional
> commits since the last revision:
>
> - Small doc fix
> - Attend to @wangweij's code review comments - in particular a large
> clean-up of the test helper and the output it creates
> - Attend to remaining comments from @smemery
test/jdk/sun/security/krb5/native/NativeCacheTest.java line 37:
> 35: * --add-exports java.security.jgss/sun.security.jgss.krb5=ALL-UNNAMED
> 36: * --add-exports java.base/sun.security.util=ALL-UNNAMED
> 37: * --add-exports java.base/jdk.internal.misc=ALL-UNNAMED
Use
@modules java.security.jgss/sun.security.krb5
java.security.jgss/sun.security.krb5.internal
...
It applies to both compile and run.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/28075#discussion_r2529265765
