Re: [PATCH] rust: task: clarify comments on task UID accessors

[Jann Horn]

On Fri, Feb 13, 2026 at 3:43 PM Jann Horn <jannh@xxxxxxxxxx> wrote:
> I agree with that; I don't know what that failing test was. (Todd
> would probably know.) My understanding is:
>
> In the current version, the ->sender_euid reported to a transaction's
> recipient is the EUID of the sending process *at the time the
> transaction is received by the recipient*. (This is wrong if the
> sending process changed credentials after sending the transaction, and
> especially dangerous if the sending process went through a setuid
> execution in the meantime.)

Sorry, looks like I didn't read carefully enough when I was writing my
last mail, and I forgot the details since I last really looked at
this...
What I wrote above is wrong.

In current binder (both C and Rust versions), the ->sender_euid
reported to the recipient is the current EUID of the main thread of
the process that opened /dev/binder, recorded at the time the
transaction is sent.

In C binder, I believe there is no check that the thread actually
making the transaction is part of the process that opened /dev/binder;
Rust binder checks for this in get_current_thread().