linux-kernel - Re: [PATCH ghak10 v8 2/2] ntp: Audit NTP parameters adjustment

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Message-ID: <CAHC9VhRmfGmYSQ0h1HosJ9OWZz1M69VhMrJopJuNdtoKynikcQ@mail.gmail.com>
Date:   Mon, 15 Apr 2019 18:28:37 -0400
From:   Paul Moore <paul@...l-moore.com>
To:     Ondrej Mosnacek <omosnace@...hat.com>
Cc:     linux-audit@...hat.com, Richard Guy Briggs <rgb@...hat.com>,
        Steve Grubb <sgrubb@...hat.com>,
        Miroslav Lichvar <mlichvar@...hat.com>,
        John Stultz <john.stultz@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Stephen Boyd <sboyd@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH ghak10 v8 2/2] ntp: Audit NTP parameters adjustment

On Wed, Apr 10, 2019 at 5:14 AM Ondrej Mosnacek <omosnace@...hat.com> wrote:
>
> Emit an audit record every time selected NTP parameters are modified
> from userspace (via adjtimex(2) or clock_adjtime(2)). These parameters
> may be used to indirectly change system clock, and thus their
> modifications should be audited.
>
> Such events will now generate records of type AUDIT_TIME_ADJNTPVAL
> containing the following fields:
>   - op -- which value was adjusted:
>     - offset -- corresponding to the time_offset variable
>     - freq   -- corresponding to the time_freq variable
>     - status -- corresponding to the time_status variable
>     - adjust -- corresponding to the time_adjust variable
>     - tick   -- corresponding to the tick_usec variable
>     - tai    -- corresponding to the timekeeping's TAI offset
>   - old -- the old value
>   - new -- the new value
>
> Example records:
>
> type=TIME_ADJNTPVAL msg=audit(1530616044.507:7): op=status old=64 new=8256
> type=TIME_ADJNTPVAL msg=audit(1530616044.511:11): op=freq old=0 new=49180377088000
>
> The records of this type will be associated with the corresponding
> syscall records.
>
> An overview of parameter changes that can be done via do_adjtimex()
> (based on information from Miroslav Lichvar) and whether they are
> audited:
>   __timekeeping_set_tai_offset() -- sets the offset from the
>                                     International Atomic Time
>                                     (AUDITED)
>   NTP variables:
>     time_offset -- can adjust the clock by up to 0.5 seconds per call
>                    and also speed it up or slow down by up to about
>                    0.05% (43 seconds per day) (AUDITED)
>     time_freq -- can speed up or slow down by up to about 0.05%
>                  (AUDITED)
>     time_status -- can insert/delete leap seconds and it also enables/
>                    disables synchronization of the hardware real-time
>                    clock (AUDITED)
>     time_maxerror, time_esterror -- change error estimates used to
>                                     inform userspace applications
>                                     (NOT AUDITED)
>     time_constant -- controls the speed of the clock adjustments that
>                      are made when time_offset is set (NOT AUDITED)
>     time_adjust -- can temporarily speed up or slow down the clock by up
>                    to 0.05% (AUDITED)
>     tick_usec -- a more extreme version of time_freq; can speed up or
>                  slow down the clock by up to 10% (AUDITED)
>
> Signed-off-by: Ondrej Mosnacek <omosnace@...hat.com>
> Reviewed-by: Richard Guy Briggs <rgb@...hat.com>
> Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
> ---
>  include/linux/audit.h      | 61 ++++++++++++++++++++++++++++++++++++++
>  include/uapi/linux/audit.h |  1 +
>  kernel/auditsc.c           | 22 ++++++++++++++
>  kernel/time/ntp.c          | 22 ++++++++++++--
>  kernel/time/ntp_internal.h |  4 ++-
>  kernel/time/timekeeping.c  |  7 ++++-
>  6 files changed, 112 insertions(+), 5 deletions(-)

Merged into audit/next, thanks.

-- 
paul moore
www.paul-moore.com