binder: use current_euid() for transaction sender identity

binder: use current_euid() for transaction sender identity

Binder currently uses task_euid(proc->tsk) as the transaction sender EUID,
where proc->tsk is the main thread of the process that opened /dev/binder.
That's not clean; use the subjective EUID of the current task instead.

Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260213-binder-uid-v1-1-7b795ae05523@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>