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Date:   Tue, 20 Oct 2020 09:01:20 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Alexey Budankov <alexey.budankov@linux.intel.com>
Cc:     Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        "linux-security-module@vger.kernel.org" 
        <linux-security-module@vger.kernel.org>,
        "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
        linux-man@vger.kernel.org
Subject: Re: [PATCH v1 0/2] doc/admin-guide: update perf-security.rst with
 CAP_PERFMON usage flows
Message-ID: <20201020120120.GA2294271@kernel.org>
References: <161a51d3-7cdf-f9ee-c438-42bb7404693e@linux.intel.com>
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Em Mon, Oct 19, 2020 at 08:15:14PM +0300, Alexey Budankov escreveu:
> 
> Assignment of CAP_PERFMON [1] Linux capability to an executable located
> on a file system requires extended attributes (xattrs) [2] to be supported
> by the file system. Even if the file system supports xattrs an fs device
> should be mounted with permission to use xattrs for files located on the
> device (e.g. without nosuid option [3]). No xattrs support and nosuid
> mounts are quite common in HPC and Cloud multiuser environments thus
> applicability of privileged Perf user groups based on file capabilities
> [4] is limited in that environments. Alternative method to confer Linux
> capabilities into a process does still exist and it is thru creation of
> capabilities-enabled-semi-privileged shell environment. Usage of this
> method to extend privileged Perf user groups approach is documented in
> this patch set as an extension to perf-security.rst admin guide file.
> 
> [1] https://man7.org/linux/man-pages/man7/capabilities.7.html
> [2] https://man7.org/linux/man-pages/man7/xattr.7.html
> [3] https://man7.org/linux/man-pages/man8/mount.8.html
> [4] https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html#privileged-perf-users-groups


Thanks, applied.

- Arnaldo

 
> ---
> Alexey Budankov (2):
>   doc/admin-guide: note credentials consolidation under CAP_PERFMON
>   doc/admin-guide: document creation of CAP_PERFMON privileged shell
> 
>  Documentation/admin-guide/perf-security.rst | 81 ++++++++++++++++++---
>  1 file changed, 70 insertions(+), 11 deletions(-)
> 
> -- 
> 2.24.1
> 

-- 

- Arnaldo