From: Oleg Nesterov <oleg@redhat.com>
To: Andrei Vagin <avagin@google.com>
Cc: Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@amacapital.net>,
Will Drewry <wad@chromium.org>,
Christian Brauner <brauner@kernel.org>,
linux-kernel@vger.kernel.org,
Tycho Andersen <tandersen@netflix.com>,
Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH 0/3 v2] seccomp: improve handling of SECCOMP_IOCTL_NOTIF_RECV
Date: Thu, 23 May 2024 11:33:35 +0200 [thread overview]
Message-ID: <20240523093334.GD15163@redhat.com> (raw)
In-Reply-To: <20240523014540.372255-1-avagin@google.com>
On 05/23, Andrei Vagin wrote:
>
> This patch set addresses two problems with the SECCOMP_IOCTL_NOTIF_RECV
> ioctl:
> * it doesn't return when the seccomp filter becomes unused (all tasks
> have exited).
> * EPOLLHUP is triggered not when a task exits, but rather when its zombie
> is collected.
It seems that 2/3 also fixes another minor problem.
Suppose that a group leader installs the new filter without
SECCOMP_FILTER_FLAG_TSYNC, exits, and becomes a zombie. It can't be
released until all its sub-threads exit.
After that, without 2/3, SECCOMP_FILTER_FLAG_TSYNC from any other thread
can never succeed, seccomp_can_sync_threads() will check a zombie leader
and is_ancestor() will fail.
Right?
Oleg.
next prev parent reply other threads:[~2024-05-23 9:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-23 1:45 [PATCH 0/3 v2] seccomp: improve handling of SECCOMP_IOCTL_NOTIF_RECV Andrei Vagin
2024-05-23 1:45 ` [PATCH 1/3] seccomp: interrupt SECCOMP_IOCTL_NOTIF_RECV when all users have exited Andrei Vagin
2024-05-23 8:59 ` Oleg Nesterov
2024-05-24 17:47 ` Andrei Vagin
2024-05-23 1:45 ` [PATCH 2/3] seccomp: release task filters when the task exits Andrei Vagin
2024-05-23 9:00 ` Oleg Nesterov
2024-06-26 18:57 ` Kees Cook
2024-05-23 1:45 ` [PATCH 3/3] selftests/seccomp: add test for NOTIF_RECV and unused filters Andrei Vagin
2024-05-23 9:33 ` Oleg Nesterov [this message]
2024-06-25 0:19 ` [PATCH 0/3 v2] seccomp: improve handling of SECCOMP_IOCTL_NOTIF_RECV Andrei Vagin
2024-06-25 0:17 ` Andrei Vagin
2024-06-26 19:00 ` Kees Cook
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