Re: [PATCH ghak10 v5 1/2] audit: Add functions to log time adjustments

Richard Guy Briggs
2018-09-14T16:24:03Z

On 2018-09-14 11:34, Steve Grubb wrote:
> On Friday, September 14, 2018 11:16:43 AM EDT Richard Guy Briggs wrote:
> > On 2018-09-13 23:18, Paul Moore wrote:
> > > On Fri, Aug 24, 2018 at 8:00 AM Ondrej Mosnacek <omosnace@redhat.com>
> wrote:
> > > > This patch adds two auxiliary record types that will be used to
> > > > annotate
> > > > the adjtimex SYSCALL records with the NTP/timekeeping values that have
> > > > been changed.
> > > >
> > > > Next, it adds two functions to the audit interface:
> > > > - audit_tk_injoffset(), which will be called whenever a timekeeping
> > > >
> > > > offset is injected by a syscall from userspace,
> > > >
> > > > - audit_ntp_adjust(), which will be called whenever an NTP internal
> > > >
> > > > variable is changed by a syscall from userspace.
> > > >
> > > > Quick reference for the fields of the new records:
> > > > AUDIT_TIME_INJOFFSET
> > > >
> > > > sec - the 'seconds' part of the offset
> > > > nsec - the 'nanoseconds' part of the offset
> > > >
> > > > AUDIT_TIME_ADJNTPVAL
> > > >
> > > > 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
> > >
> > > I understand that reusing "op" is tempting, but the above aren't
> > > really operations, they are state variables which are being changed.
> > > Using the CONFIG_CHANGE record as a basis, I wonder if we are better
> > >
> > > off with something like the following:
> > > type=TIME_CHANGE =<value_new> old=<value_old>
> > >
> > > ... you might need to preface the variable names with something like
> > > "ntp_" or "offset_". You'll notice I'm also suggesting we use a
> > > single record type here; is there any reason why two records types are
> > > required?
> >
> > Why not do something like:
> >
> > type=TIME_CHANGE var= new=<value_new> old=<value_old>
> >
> > So that we don't pollute the field namespace *and* create 8 variants on
> > the same record format? This shouldn't be much of a concern with binary
> > record formats, but we're stuck with the current parsing scheme for now.
>
> Something like this or the other format is fine. Neither hurt parsing because
> these are not searchable fields. We only have issues when it involves a
> searchable field name.

Ok, fair enough. Thanks Steve.

> HTH...
>
> -Steve
>
> > > > old - the old value
> > > > new - the new value
> > > >
> > > > Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> > > > ---
> > > >
> > > > include/linux/audit.h | 21 +++++++++++++++++++++
> > > > include/uapi/linux/audit.h | 2 ++
> > > > kernel/auditsc.c | 15 +++++++++++++++
> > > > 3 files changed, 38 insertions(+)
> > >
> > > A reminder that we need tests for these new records and a RFE page on the
> > > wiki:
> > >
> > > * https://github.com/linux-audit/audit-testsuite
> > > * https://github.com/linux-audit/audit-kernel/wiki
> >
> > - RGB

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
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