binder: fix test regression due to sender_euid change

commit c21a80ca0684ec2910344d72556c816cb8940c01 upstream.

This is a partial revert of commit
29bc22ac5e5b ("binder: use euid from cred instead of using task").
Setting sender_euid using proc->cred caused some Android system test
regressions that need further investigation. It is a partial
reversion because subsequent patches rely on proc->cred.

Fixes: 29bc22ac5e5b ("binder: use euid from cred instead of using task")
Cc: stable@vger.kernel.org # 4.4+
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: I9b1769a3510fed250bb21859ef8beebabe034c66
Link: https://lore.kernel.org/r/20211112180720.2858135-1-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 49fb741..cffbe57 100644 (file)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2710,7 +2710,7 @@ static void binder_transaction(struct binder_proc *proc,
                t->from = thread;
        else
                t->from = NULL;
-       t->sender_euid = proc->cred->euid;
+       t->sender_euid = task_euid(proc->tsk);
        t->to_proc = target_proc;
        t->to_thread = target_thread;
        t->code = tr->code;