[PATCH] binder: fix test regression due to sender_euid change

[Todd Kjos <tkjos@google.com>]

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.

Cc: stable@vger.kernel.org # 4.4+
Fixes: 29bc22ac5e5b ("binder: use euid from cred instead of using task")
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: I9b1769a3510fed250bb21859ef8beebabe034c66
---
- the issue was introduced in 5.16-rc1, so please apply to 5.16
- this should apply cleanly to all stable branches back to 4.4
  that contain "binder: use euid from cred instead of using task"


 drivers/android/binder.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 49fb74196d02..cffbe57a8e08 100644
--- 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;
-- 
2.34.0.rc1.387.gb447b232ab-goog