linux-kernel - Re: [PATCH v8 12/12] doc/admin-guide: update kernel.rst with CAP

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Message-ID: <20200405150557.GP9917@kernel.org>
Date:   Sun, 5 Apr 2020 12:05:57 -0300
From:   Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        James Morris <jmorris@...ei.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Serge Hallyn <serge@...lyn.com>, Jiri Olsa <jolsa@...hat.com>,
        Song Liu <songliubraving@...com>,
        Andi Kleen <ak@...ux.intel.com>,
        Stephane Eranian <eranian@...gle.com>,
        Igor Lubashev <ilubashe@...mai.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>,
        "selinux@...r.kernel.org" <selinux@...r.kernel.org>,
        "intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        linux-man@...r.kernel.org
Subject: Re: [PATCH v8 12/12] doc/admin-guide: update kernel.rst with
 CAP_PERFMON information

Em Sun, Apr 05, 2020 at 05:54:37PM +0300, Alexey Budankov escreveu:
> 
> On 05.04.2020 17:41, Alexey Budankov wrote:
> > 
> > On 05.04.2020 17:10, Arnaldo Carvalho de Melo wrote:
> >> Em Thu, Apr 02, 2020 at 11:54:39AM +0300, Alexey Budankov escreveu:
> >>>
> >>> Update kernel.rst documentation file with the information
> >>> related to usage of CAP_PERFMON capability to secure performance
> >>> monitoring and observability operations in system.
> >>
> >> This one is failing in my perf/core branch, please take a look. I'm
> 
> Please try applying this:

Thanks, applied with the original commit log message,

- Arnaldo
 
> ---
>  Documentation/admin-guide/sysctl/kernel.rst | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
> index 335696d3360d..aaa5bbcd1e33 100644
> --- a/Documentation/admin-guide/sysctl/kernel.rst
> +++ b/Documentation/admin-guide/sysctl/kernel.rst
> @@ -709,7 +709,13 @@ perf_event_paranoid
>  ===================
>  
>  Controls use of the performance events system by unprivileged
> -users (without CAP_SYS_ADMIN).  The default value is 2.
> +users (without CAP_PERFMON).  The default value is 2.
> +
> +For backward compatibility reasons access to system performance
> +monitoring and observability remains open for CAP_SYS_ADMIN
> +privileged processes but CAP_SYS_ADMIN usage for secure system
> +performance monitoring and observability operations is discouraged
> +with respect to CAP_PERFMON use cases.
>  
>  ===  ==================================================================
>   -1  Allow use of (almost) all events by all users.
> @@ -718,13 +724,13 @@ users (without CAP_SYS_ADMIN).  The default value is 2.
>       ``CAP_IPC_LOCK``.
>  
>  >=0  Disallow ftrace function tracepoint by users without
> -     ``CAP_SYS_ADMIN``.
> +     ``CAP_PERFMON``.
>  
> -     Disallow raw tracepoint access by users without ``CAP_SYS_ADMIN``.
> +     Disallow raw tracepoint access by users without ``CAP_PERFMON``.
>  
> ->=1  Disallow CPU event access by users without ``CAP_SYS_ADMIN``.
> +>=1  Disallow CPU event access by users without ``CAP_PERFMON``.
>  
> ->=2  Disallow kernel profiling by users without ``CAP_SYS_ADMIN``.
> +>=2  Disallow kernel profiling by users without ``CAP_PERFMON``.
>  ===  ==================================================================
>  
> ---
> 
> Thanks,
> Alexey
> 
> > 
> > Trying to reproduce right now. What kind of failure do you see?
> > Please share some specifics so I could follow up properly.
> > 
> > Thanks,
> > Alexey
> > 
> >> pushing my perf/core branch with this series applied, please check that
> >> everything is ok, I'll do some testing now, but it all seems ok.
> >>
> >> Thanks,
> >>
> >> - Arnaldo
> >>  
> >>> Signed-off-by: Alexey Budankov <alexey.budankov@...ux.intel.com>
> >>> ---
> >>>  Documentation/admin-guide/sysctl/kernel.rst | 16 +++++++++++-----
> >>>  1 file changed, 11 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
> >>> index def074807cee..b06ae9389809 100644
> >>> --- a/Documentation/admin-guide/sysctl/kernel.rst
> >>> +++ b/Documentation/admin-guide/sysctl/kernel.rst
> >>> @@ -720,20 +720,26 @@ perf_event_paranoid:
> >>>  ====================
> >>>  
> >>>  Controls use of the performance events system by unprivileged
> >>> -users (without CAP_SYS_ADMIN).  The default value is 2.
> >>> +users (without CAP_PERFMON). The default value is 2.
> >>> +
> >>> +For backward compatibility reasons access to system performance
> >>> +monitoring and observability remains open for CAP_SYS_ADMIN
> >>> +privileged processes but CAP_SYS_ADMIN usage for secure system
> >>> +performance monitoring and observability operations is discouraged
> >>> +with respect to CAP_PERFMON use cases.
> >>>  
> >>>  ===  ==================================================================
> >>>   -1  Allow use of (almost) all events by all users
> >>>  
> >>>       Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK
> >>>  
> >>> ->=0  Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN
> >>> +>=0  Disallow ftrace function tracepoint by users without CAP_PERFMON
> >>>  
> >>> -     Disallow raw tracepoint access by users without CAP_SYS_ADMIN
> >>> +     Disallow raw tracepoint access by users without CAP_PERFMON
> >>>  
> >>> ->=1  Disallow CPU event access by users without CAP_SYS_ADMIN
> >>> +>=1  Disallow CPU event access by users without CAP_PERFMON
> >>>  
> >>> ->=2  Disallow kernel profiling by users without CAP_SYS_ADMIN
> >>> +>=2  Disallow kernel profiling by users without CAP_PERFMON
> >>>  ===  ==================================================================
> >>>  
> >>>  
> >>> -- 
> >>> 2.24.1
> >>>
> >>

-- 

- Arnaldo