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From: Andi Kleen <ak@linux.intel.com>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Ingo Molnar <mingo@redhat.com>, Jiri Olsa <jolsa@redhat.com>,
	elena.reshetova@intel.com,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jann Horn <jannh@google.com>, Kees Cook <keescook@chromium.org>,
	Stephane Eranian <eranian@google.com>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1 0/3] Introduce CAP_SYS_PERFMON capability for secure Perf users groups
Date: Wed, 11 Dec 2019 12:36:48 -0800
Message-ID: <20191211203648.GA862919@tassilo.jf.intel.com> (raw)
In-Reply-To: <16e9e399-2ebf-261f-eee5-cf9ace2a82b9@schaufler-ca.com>

> > In this circumstances CAP_SYS_PERFMON looks like smart balanced advancement that
> > trade-offs between perf_events subsystem extensions, required level of control
> > and configurability of perf_events, existing users adoption effort, and it brings
> > security hardening benefits of decreasing attack surface for the existing users
> > and use cases.
> 
> I'm not 100% opposed to CAP_SYS_PERFMON. I am 100% opposed to new capabilities
> that have a single use. Surely there are other CAP_SYS_ADMIN users that [cs]ould
> be converted to CAP_SYS_PERFMON as well. If there is a class of system performance
> privileged operations, say a dozen or so, you may have a viable argument.

perf events is not a single use. It has a bazillion of sub functionalities,
including hardware tracing, software tracing, pmu counters, software counters,
uncore counters, break points and various other stuff in its PMU drivers.

See it more as a whole quite heterogenous driver subsystem.

I guess CAP_SYS_PERFMON is not a good name because perf is much more
than just Perfmon. Perhaps call it CAP_SYS_PERF_EVENTS

-Andi

  reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-05 16:15 Alexey Budankov
2019-12-05 16:19 ` [PATCH v1 1/3] capabilities: introduce CAP_SYS_PERFMON to kernel and user space Alexey Budankov
2019-12-05 16:21 ` [PATCH v1 2/3] perf/core: apply CAP_SYS_PERFMON to CPUs and kernel monitoring Alexey Budankov
2019-12-05 16:22 ` [PATCH v1 3/3] perf tool: extend Perf tool with CAP_SYS_PERFMON support Alexey Budankov
2019-12-05 16:49 ` [PATCH v1 0/3] Introduce CAP_SYS_PERFMON capability for secure Perf users groups Casey Schaufler
2019-12-05 17:05   ` Alexey Budankov
2019-12-05 17:33     ` Casey Schaufler
2019-12-05 18:11       ` Andi Kleen
2019-12-05 18:37       ` Alexey Budankov
2019-12-11 10:52       ` Alexey Budankov
2019-12-11 15:24         ` Peter Zijlstra
2019-12-11 17:00           ` Alexey Budankov
2019-12-11 18:09         ` Casey Schaufler
2019-12-11 20:36           ` Andi Kleen [this message]
2019-12-11 21:25             ` Casey Schaufler
2019-12-12 14:24             ` Stephen Smalley
2019-12-15 11:53               ` Alexey Budankov
2019-12-11 19:04       ` Stephane Eranian

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