linux-kernel - Re: [PATCH v5] pidfd: add ioctl to retrieve pid info

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241006185537.GC10213@redhat.com>
Date: Sun, 6 Oct 2024 20:55:38 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Luca Boccassi <luca.boccassi@...il.com>
Cc: linux-kernel@...r.kernel.org, christian@...uner.io
Subject: Re: [PATCH v5] pidfd: add ioctl to retrieve pid info

On 10/06, Luca Boccassi wrote:
>
> I see, so what should I do here then? Check both? Or none?

I don't know, because I don't know how are you going to use this API.

> The caller
> needs to verify that the data is still valid at the point they use it
> anyway,

So "none" should work fine? Just it should be documented that, say,
kinfo.pid can be 0 if we race with the exiting task.

Just in case, you can also use lock_task_sighand() || return -ESRCH,
this way kinfo.*pid can't be zero. But I don't think this will buy too
much, the task can exit right after pidfd_info() returns.

Oleg.