Re: [PATCH ghak90 (was ghak32) V4 03/10] audit: log container info of syscalls

[Paul Moore]

On Wed, Oct 24, 2018 at 11:15 AM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> On 2018-10-19 19:16, Paul Moore wrote:
> > On Sun, Aug 5, 2018 at 4:32 AM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> > > Create a new audit record AUDIT_CONTAINER 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=0000000000000000 cap_fi=0000000000000000 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=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
> > > type=PROCTITLE msg=audit(1519924845.499:257): proctitle=62617368002D6300736C65657020313B206563686F2074657374203E202F746D702F746D70636F6E7461696E65726964
> > > type=CONTAINER msg=audit(1519924845.499:257): op=task contid=123458
> > >
> > > See: https://github.com/linux-audit/audit-kernel/issues/90
> > > See: https://github.com/linux-audit/audit-userspace/issues/51
> > > See: https://github.com/linux-audit/audit-testsuite/issues/64
> > > See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID
> > > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> > > Acked-by: Serge Hallyn <serge@xxxxxxxxxx>
> > > Acked-by: Steve Grubb <sgrubb@xxxxxxxxxx>
> > > ---
> > >  include/linux/audit.h      |  7 +++++++
> > >  include/uapi/linux/audit.h |  1 +
> > >  kernel/audit.c             | 24 ++++++++++++++++++++++++
> > >  kernel/auditsc.c           |  3 +++
> > >  4 files changed, 35 insertions(+)
> >
> > ...
> >
> > > @@ -2045,6 +2045,30 @@ 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
> > > + * @tsk: task to be recorded
> > > + * @context: task or local context for record
> > > + * @op: contid string description
> > > + */
> > > +int audit_log_contid(struct task_struct *tsk,
> > > +                            struct audit_context *context, char *op)
> > > +{
> > > +       struct audit_buffer *ab;
> > > +
> > > +       if (!audit_contid_set(tsk))
> > > +               return 0;
> > > +       /* Generate AUDIT_CONTAINER record with container ID */
> > > +       ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONTAINER);
> > > +       if (!ab)
> > > +               return -ENOMEM;
> > > +       audit_log_format(ab, "op=%s contid=%llu",
> > > +                        op, audit_get_contid(tsk));
> > > +       audit_log_end(ab);
> > > +       return 0;
> > > +}
> > > +EXPORT_SYMBOL(audit_log_contid);
> >
> > As discussed in the previous iteration of the patch, I prefer
> > AUDIT_CONTAINER_ID here over AUDIT_CONTAINER.  If you feel strongly
> > about keeping it as-is with AUDIT_CONTAINER I suppose I could live
> > with that, but it is isn't my first choice.
>
> I don't have a strong opinion on this one, mildly preferring the shorter
> one only because it is shorter.

We already have multiple AUDIT_CONTAINER* record types, so it seems as
though we should use "AUDIT_CONTAINER" as a prefix of sorts, rather
than a type itself.

> > However, I do care about the "op" field in this record.  It just
> > doesn't make any sense; the way you are using it it is more of a
> > context field than an operations field, and even then why is the
> > context important from a logging and/or security perspective?  Drop it
> > please.
>
> I'll rename it to whatever you like.  I'd suggest "ref=".  The reason I
> think it is important is there are multiple sources that aren't always
> obvious from the other records to which it is associated.  In the case
> of ptrace and signals, there can be many target tasks listed (OBJ_PID)
> with no other way to distinguish the matching audit container identifier
> records all for one event.  This is in addition to the default syscall
> container identifier record.  I'm not currently happy with the text
> content to link the two, but that should be solvable (most obvious is
> taret PID).  Throwing away this information seems shortsighted.

It would be helpful if you could generate real audit events
demonstrating the problems you are describing, as well as a more
standard syscall event, so we can discuss some possible solutions.

-- 
paul moore
www.paul-moore.com