linux-kernel - Re: [PATCH RESEND2] ptrace: make ptrace() fail if the tracee changed its pid unexpectedly

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20210512143855.GB19594@redhat.com>
Date:   Wed, 12 May 2021 16:38:56 +0200
From:   Oleg Nesterov <oleg@...hat.com>
To:     Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Eugene Syromiatnikov <esyr@...hat.com>,
        Jan Kratochvil <jan.kratochvil@...hat.com>,
        Michael Kerrisk <mtk.manpages@...il.com>,
        Pedro Alves <palves@...hat.com>,
        Simon Marchi <simon.marchi@...icios.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND2] ptrace: make ptrace() fail if the tracee changed
 its pid unexpectedly

Hi Mathieu,

On 05/12, Mathieu Desnoyers wrote:
>
> Out of curiosity: what makes it OK to use either the current task or its
> parent's pid namespace in this specific case ? What happens if they are
> in different pid namespaces ?

Because in this case current == task->parent == debugger.

Just in case... task->real_parent is, well, "real parent", the parent which
forked this task.

task->parent == task->real_parent unless this task is ptraced, in this case
task->parent == debugger.

Oleg.