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From: Christian Brauner <christian.brauner@ubuntu.com>
To: Sargun Dhillon <sargun@sargun.me>
Cc: linux-kernel@vger.kernel.org,
	containers@lists.linux-foundation.org, linux-api@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, tycho@tycho.ws, jannh@google.com,
	cyphar@cyphar.com, oleg@redhat.com, luto@amacapital.net,
	viro@zeniv.linux.org.uk, gpascutto@mozilla.com,
	ealvarez@mozilla.com, fweimer@redhat.com, jld@mozilla.com
Subject: Re: [PATCH v3 0/4] Add pidfd getfd ioctl (Was Add ptrace get_fd request)
Date: Tue, 17 Dec 2019 04:02:29 +0100	[thread overview]
Message-ID: <20191217030229.2lcfrdbcc6ynumht@wittgenstein> (raw)
In-Reply-To: <20191217005842.GA14379@ircssh-2.c.rugged-nimbus-611.internal>

On Tue, Dec 17, 2019 at 12:58:45AM +0000, Sargun Dhillon wrote:
> This patchset introduces a mechanism to capture file descriptors from other
> processes by pidfd and ioctl. Although this can be achieved using

I like the idea in general as it's quite useful in general. And also for
the seccomp notifier and probably for CRIU too.
A few things that crossed my mind.
A thing I'm worried about is that this will be a stepping stone for
people argue for an fd-replacement feature though I think that
fd-injection not replacement might be sufficient.

I wonder whether we need to worry about special file descriptors, i.e.
anything anon-inode based, or devpts devices but I guess those concerns
already apply to ptrace anyway.

One more thing, with GETFD it seems useful to me that later we can add
a new flag - like I suggested in the previous version - to the seccomp
notifier that would allow a caller to request that with each seccomp
message received via the notifier ioctl() from the kernel a pidfd is
sent along. This would make it quite elegant to get fds for the
supervised task.

Christian

      reply	other threads:[~2019-12-17  3:02 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-17  0:58 [PATCH v3 0/4] Add pidfd getfd ioctl (Was Add ptrace get_fd request) Sargun Dhillon
2019-12-17  3:02 ` Christian Brauner [this message]

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