Re: [PATCH ghak90 V6 04/10] audit: log container info of syscalls

[Ondrej Mosnacek <omosnace@redhat.com>]

On Thu, May 30, 2019 at 12:16 AM Paul Moore <paul@paul-moore.com> wrote:
> On Mon, Apr 8, 2019 at 11:40 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> >
> > Create a new audit record AUDIT_CONTAINER_ID to document the audit
> > container identifier of a process if it is present.
> >
> > Called from audit_log_exit(), syscalls are covered.
> >
> > A sample raw event:
> > type=SYSCALL msg=audit(1519924845.499:257): arch=c000003e syscall=257 success=yes exit=3 a0=ffffff9c a1=56374e1cef30 a2=241 a3=1b6 items=2 ppid=606 pid=635 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=3 comm="bash" exe="/usr/bin/bash" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="tmpcontainerid"
> > type=CWD msg=audit(1519924845.499:257): cwd="/root"
> > type=PATH msg=audit(1519924845.499:257): item=0 name="/tmp/" inode=13863 dev=00:27 mode=041777 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:tmp_t:s0 nametype= PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0
> > type=PATH msg=audit(1519924845.499:257): item=1 name="/tmp/tmpcontainerid" inode=17729 dev=00:27 mode=0100644 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0
> > type=PROCTITLE msg=audit(1519924845.499:257): proctitle=62617368002D6300736C65657020313B206563686F2074657374203E202F746D702F746D70636F6E7461696E65726964
> > type=CONTAINER_ID msg=audit(1519924845.499:257): contid=123458
> >
> > Please see the github audit kernel issue for the main feature:
> >   https://github.com/linux-audit/audit-kernel/issues/90
> > Please see the github audit userspace issue for supporting additions:
> >   https://github.com/linux-audit/audit-userspace/issues/51
> > Please see the github audit testsuiite issue for the test case:
> >   https://github.com/linux-audit/audit-testsuite/issues/64
> > Please see the github audit wiki for the feature overview:
> >   https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > Acked-by: Serge Hallyn <serge@hallyn.com>
> > Acked-by: Steve Grubb <sgrubb@redhat.com>
> > Acked-by: Neil Horman <nhorman@tuxdriver.com>
> > Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
> > ---
> >  include/linux/audit.h      |  5 +++++
> >  include/uapi/linux/audit.h |  1 +
> >  kernel/audit.c             | 20 ++++++++++++++++++++
> >  kernel/auditsc.c           | 20 ++++++++++++++------
> >  4 files changed, 40 insertions(+), 6 deletions(-)
>
> ...
>
> > diff --git a/kernel/audit.c b/kernel/audit.c
> > index 182b0f2c183d..3e0af53f3c4d 100644
> > --- a/kernel/audit.c
> > +++ b/kernel/audit.c
> > @@ -2127,6 +2127,26 @@ void audit_log_session_info(struct audit_buffer *ab)
> >         audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
> >  }
> >
> > +/*
> > + * audit_log_contid - report container info
> > + * @context: task or local context for record
> > + * @contid: container ID to report
> > + */
> > +void audit_log_contid(struct audit_context *context, u64 contid)
> > +{
> > +       struct audit_buffer *ab;
> > +
> > +       if (!audit_contid_valid(contid))
> > +               return;
> > +       /* Generate AUDIT_CONTAINER_ID record with container ID */
> > +       ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONTAINER_ID);
> > +       if (!ab)
> > +               return;
> > +       audit_log_format(ab, "contid=%llu", (unsigned long long)contid);
>
> We have a consistency problem regarding how to output the u64 contid
> values; this function uses an explicit cast, others do not.  According
> to Documentation/core-api/printk-formats.rst the recommendation for
> u64 is %llu (or %llx, if you want hex).  Looking quickly through the
> printk code this appears to still be correct.  I suggest we get rid of
> the cast (like it was in v5).

IIRC it was me who suggested to add the casts. I didn't realize that
the kernel actually guarantees that "%llu" will always work with u64.
Taking that into account I rescind my request to add the cast. Sorry
for the false alarm.

>
> > +       audit_log_end(ab);
> > +}
> > +EXPORT_SYMBOL(audit_log_contid);
>
> --
> paul moore
> www.paul-moore.com

--
Ondrej Mosnacek <omosnace at redhat dot com>
Software Engineer, Security Technologies
Red Hat, Inc.