Re: BUG: selinux-testsuite binder tests fail with CONFIG_ANDROID_BINDER_IPC_RUST=y

[Alice Ryhl <aliceryhl@google.com>]

On Sun, Oct 18, 2026 at 06:53:49PM +0200, Greg Kroah-Hartman wrote:
> On Sun, Oct 18, 2026 at 06:36:04PM +0200, Ondrej Mosnáček wrote:
> > Hello Android binder maintainers,
> > 
> > Fedora Linux has recently enabled CONFIG_ANDROID_BINDER_IPC_RUST [1],
> > which turns out to cause the binder tests of selinux-testsuite [2] to
> > fail.
> > 
> > Minimal reproducer (no SELinux involved):
> > # git clone https://github.com/SELinuxProject/selinux-testsuite
> > # cd selinux-testsuite/tests/binder
> > # make
> > # ./init_binder.sh
> > # setenforce 0   ### <-- may be needed if SELinux is enabled
> > # ./manager -n &
> > # sleep 1
> > # ./service_provider -n &
> > # sleep 1
> > # ./client -n -c -r 3
> > Client ioctl BINDER_WRITE_READ error: Invalid argument
> > #
> > 
> > With only CONFIG_ANDROID_BINDER_IPC=y the last command succeeds.
> > 
> > The issue reproduces even on a kernel compiled from commit
> > eafedbc7c050, so it seems to date back to the origin of the Rust
> > implementation. I'm not sure if it's a bug in the new kernel code or
> > some bug/wrong assumption in the testsuite code - can you please look
> > into it?
> 
> Given that the "real" binder client works, perhaps the test is wrong and
> should be fixed?

Apparently there is a divergence of behavior if the SELinux permission
`binder { impersonate }` is granted to a process, though Android never
uses this permission anywhere.

Thanks for the report.

Alice