binderfs: add extended_error feature entry

Add extended_error to the binderfs feature list, to help userspace
determine whether the BINDER_GET_EXTENDED_ERROR ioctl is supported by
the binder driver.

Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20220429235644.697372-4-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

selftests/binderfs: Improve message to provide more info

Currently the binderfs test says what failure it encountered
without saying why it may occurred when it fails to mount
binderfs. So, Warn about enabling CONFIG_ANDROID_BINDERFS in the
running kernel.

Signed-off-by: Karthik Alapati <mail@karthek.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/binderfs: add test for feature files

Verify that feature files are created successfully after mounting a
binderfs instance. Note that only "oneway_spam_detection" feature is
tested with this patch as it is currently the only feature listed.

Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20210715031805.1725878-3-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

selftests: binderfs: use SKIP instead of XFAIL

XFAIL is gone since commit 9847d24af95c ("selftests/harness: Refactor XFAIL
into SKIP"), use SKIP instead.

Fixes: 9847d24af95c ("selftests/harness: Refactor XFAIL into SKIP")
Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/binderfs: Fix harness API usage

The binderfs test mixed the full harness API and the selftest API.
Adjust to use only the harness API so that the harness API can switch
to using the selftest API internally in future patches.

Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

binderfs: add stress test for binderfs binder devices

This adds a stress test that should hopefully help us catch regressions
for [1], [2], and [3].

[1]: 2669b8b0c798 ("binder: prevent UAF for binderfs devices")
[2]: f0fe2c0f050d ("binder: prevent UAF for binderfs devices II")
[3]: 211b64e4b5b6 ("binderfs: use refcount for binder control devices too")
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200313152420.138777-3-christian.brauner@ubuntu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

binderfs_test: switch from /dev to a unique per-test mountpoint

Unprivileged users will be able to create directories in there. The
unprivileged test for /dev wouldn't have worked on most systems.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200313152420.138777-2-christian.brauner@ubuntu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

binderfs: port tests to test harness infrastructure

Makes for nicer output and prepares for additional tests.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200313152420.138777-1-christian.brauner@ubuntu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

selftests: add binderfs selftests

This adds the promised selftest for binderfs. It will verify the following
things:
- binderfs mounting works
- binder device allocation works
- performing a binder ioctl() request through a binderfs device works
- binder device removal works
- binder-control removal fails
- binderfs unmounting works

The tests are performed both privileged and unprivileged. The latter
verifies that binderfs behaves correctly in user namespaces.

Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Shuah Khan <shuah@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>