From: "Serge E. Hallyn" <serge@hallyn.com>
To: Kees Cook <keescook@chromium.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
John Stultz <john.stultz@linaro.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Arjan van de Ven <arjan@linux.intel.com>,
lkml <linux-kernel@vger.kernel.org>,
Oren Laadan <orenl@cellrox.com>,
Ruchi Kandoi <kandoiruchi@google.com>,
Rom Lemarchand <romlem@android.com>,
Android Kernel Team <kernel-team@android.com>,
Todd Kjos <tkjos@google.com>, Colin Cross <ccross@android.com>,
Nick Kralevich <nnk@google.com>,
Dmitry Shmidt <dimitrysh@google.com>,
Elliott Hughes <enh@google.com>
Subject: Re: [PATCH 2/2] proc: Add /proc/<pid>/timerslack_ns interface
Date: Thu, 14 Jul 2016 15:21:53 -0500 [thread overview]
Message-ID: <20160714202153.GA5332@mail.hallyn.com> (raw)
In-Reply-To: <CAGXu5jJWDs9PkAvDsByMy8Yb+98T75nBzfH4H898pCvrTEBTYw@mail.gmail.com>
Quoting Kees Cook (keescook@chromium.org):
> On Thu, Jul 14, 2016 at 10:49 AM, Serge E. Hallyn <serge@hallyn.com> wrote:
> > Kees, you said adding a capability is hard - can you expound on that?
>
> Best I can find at the moment was discussion around CAP_COMPROMISE_KERNEL:
> http://thread.gmane.org/gmane.linux.kernel/1459165
Hm, the last discussion I recall around that topic involved a confusing
negative capability iirc, I assume CAP_COMPROMISE_KERNEL was the revamped
version.
> Basically, adding a new capability for an interface can create
> userspace compatibility problems (though perhaps in this case, it's a
> new interface, so a new capability would be okay, but it's such a
> narrow use-case and CAP_SYS_NICE fits fine).
Right, there are two ways they can be added. For new functionality,
no big deal. (Of course we'd like to avoid going beyond 64 bits of cap
too soon, so don't want to go crazy).
The other is when we want to split off a more fine-grained version of
an existing capability. Then we just have to make sure that the coarser
pre-existing capability continues to work as expected. Breaking out
CAP_SYSLOG from CAP_SYS_ADMIN was an example of that.
-serge
prev parent reply other threads:[~2016-07-14 20:21 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-17 1:06 [PATCH 0/2] Extend timer_slack_ns to u64 on 32bit systems & add /proc/<pid>/timerslack_ns John Stultz
2016-02-17 1:06 ` [PATCH 1/2] timer: Convert timer_slack_ns from unsigned long to u64 John Stultz
2016-02-17 1:06 ` [PATCH 2/2] proc: Add /proc/<pid>/timerslack_ns interface John Stultz
2016-02-17 19:35 ` Andrew Morton
2016-02-17 20:09 ` Kees Cook
2016-02-17 20:18 ` Andrew Morton
2016-02-17 20:51 ` John Stultz
2016-02-17 21:07 ` Andrew Morton
2016-02-17 22:29 ` John Stultz
2016-02-17 22:45 ` Kees Cook
2016-02-17 22:51 ` John Stultz
2016-02-17 22:53 ` Andrew Morton
2016-02-17 20:49 ` John Stultz
2016-02-18 5:59 ` [PATCH] proc: /proc/<pid>/timerslack_ns permissions fixes John Stultz
2016-02-18 17:52 ` Kees Cook
2016-07-13 23:47 ` [PATCH 2/2] proc: Add /proc/<pid>/timerslack_ns interface John Stultz
2016-07-14 3:39 ` Kees Cook
2016-07-14 5:29 ` Arjan van de Ven
2016-07-14 12:48 ` Serge E. Hallyn
2016-07-14 13:42 ` Arjan van de Ven
2016-07-14 16:01 ` John Stultz
2016-07-14 16:09 ` John Stultz
2016-07-14 17:45 ` Kees Cook
2016-07-14 17:48 ` Arjan van de Ven
2016-07-14 17:49 ` Serge E. Hallyn
2016-07-14 17:56 ` Kees Cook
2016-07-14 20:21 ` Serge E. Hallyn [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160714202153.GA5332@mail.hallyn.com \
--to=serge@hallyn.com \
--cc=akpm@linux-foundation.org \
--cc=arjan@linux.intel.com \
--cc=ccross@android.com \
--cc=dimitrysh@google.com \
--cc=enh@google.com \
--cc=john.stultz@linaro.org \
--cc=kandoiruchi@google.com \
--cc=keescook@chromium.org \
--cc=kernel-team@android.com \
--cc=linux-kernel@vger.kernel.org \
--cc=nnk@google.com \
--cc=orenl@cellrox.com \
--cc=romlem@android.com \
--cc=tglx@linutronix.de \
--cc=tkjos@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome