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Date:   Wed, 31 Oct 2018 13:44:35 +0100
From:   Oleg Nesterov <oleg@redhat.com>
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     Daniel Colascione <dancol@google.com>,
        linux-kernel@vger.kernel.org, timmurray@google.com,
        joelaf@google.com, surenb@google.com,
        Kees Cook <keescook@chromium.org>,
        Christian Brauner <christian.brauner@canonical.com>
Subject: Re: [RFC PATCH] Implement /proc/pid/kill
Message-ID: <20181031124435.GA9007@redhat.com>
References: <20181029221037.87724-1-dancol@google.com>
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On 10/30, Eric W. Biederman wrote:
>
> At a bare minimum you need to perform the permission check using the
> credentials of the opener of the file.    Which means refactoring
> kill_pid so that you can perform the permission check for killing the
> application during open.

perhaps it would be simpler to do

	my_cred = override_creds(file->f_cred);
	kill_pid(...);
	revert_creds(my_cred);

?

> But overall this looks quite reasaonble.

Agreed.

Oleg.