rust_binder: use current_euid() for transaction sender identity

rust_binder: use current_euid() for transaction sender identity

Binder currently uses from.process.task.euid() as the transaction sender
EUID, where from.process.task 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-v1-2-7b795ae05523@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>