Re: [PATCH 8/8] ima: Differentiate auditing policy rules from "audit" actions

[Stefan Berger]

On 05/30/2018 05:22 PM, Paul Moore wrote:
> On Wed, May 30, 2018 at 9:08 AM, Stefan Berger
> <stefanb@xxxxxxxxxxxxxxxxxx> wrote:
> > On 05/30/2018 08:49 AM, Richard Guy Briggs wrote:
> > > On 2018-05-24 16:11, Stefan Berger wrote:
> > > > The AUDIT_INTEGRITY_RULE is used for auditing IMA policy rules and
> > > > the IMA "audit" policy action.  This patch defines
> > > > AUDIT_INTEGRITY_POLICY_RULE to reflect the IMA policy rules.
> > > >
> > > > With this change we now call integrity_audit_msg_common() to get
> > > > common integrity auditing fields. This now produces the following
> > > > record when parsing an IMA policy rule:
> > > >
> > > > type=UNKNOWN[1806] msg=audit(1527004216.690:311): action=dont_measure \
> > > >     fsmagic=0x9fa0 pid=1613 uid=0 auid=0 ses=2 \
> > > >     subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 \
> > > >     op=policy_update cause=parse_rule comm="echo" exe="/usr/bin/echo" \
> > > >     tty=tty2 res=1
> > > >
> > > > Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxxxxxxx>
> > > > ---
> > > >    include/uapi/linux/audit.h          | 3 ++-
> > > >    security/integrity/ima/ima_policy.c | 5 +++--
> > > >    2 files changed, 5 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> > > > index 4e61a9e05132..776e0abd35cf 100644
> > > > --- a/include/uapi/linux/audit.h
> > > > +++ b/include/uapi/linux/audit.h
> > > > @@ -146,7 +146,8 @@
> > > >    #define AUDIT_INTEGRITY_STATUS            1802 /* Integrity enable
> > > > status */
> > > >    #define AUDIT_INTEGRITY_HASH      1803 /* Integrity HASH type */
> > > >    #define AUDIT_INTEGRITY_PCR       1804 /* PCR invalidation msgs */
> > > > -#define AUDIT_INTEGRITY_RULE       1805 /* policy rule */
> > > > +#define AUDIT_INTEGRITY_RULE       1805 /* IMA "audit" action policy
> > > > msgs  */
> > > > +#define AUDIT_INTEGRITY_POLICY_RULE 1806 /* IMA policy rules */
> > > >      #define AUDIT_KERNEL                2000    /* Asynchronous audit
> > > > record. NOT A REQUEST. */
> > > >    diff --git a/security/integrity/ima/ima_policy.c
> > > > b/security/integrity/ima/ima_policy.c
> > > > index 3aed25a7178a..a8ae47a386b4 100644
> > > > --- a/security/integrity/ima/ima_policy.c
> > > > +++ b/security/integrity/ima/ima_policy.c
> > > > @@ -634,7 +634,7 @@ static int ima_parse_rule(char *rule, struct
> > > > ima_rule_entry *entry)
> > > >          int result = 0;
> > > >          ab = integrity_audit_log_start(NULL, GFP_KERNEL,
> > > > -                                      AUDIT_INTEGRITY_RULE);
> > > > +                                      AUDIT_INTEGRITY_POLICY_RULE);
> > > Is it possible to connect this record to a syscall by replacing the
> > > first parameter (NULL) by current->context?
> We're likely going to need to "associate" this record (audit speak for
> making the first parameter non-NULL) with others for the audit
> container ID work.  If you do it now, Richard's patches will likely
> get a few lines smaller and that will surely make him a bit happier :)

Richard is also introducing a local context that we can then create and 
use instead of the NULL. Can we not use that then?

Steven seems to say: "We don't want to add syscall records to 
everything. That messes up schemas and existing code. The integrity 
events are 1 record in size and should stay that way. This saves disk 
space and improves readability."


> > We would have to fix current->context in this case since it is NULL. We get
> > to this location by root cat'ing a policy or writing a policy filename into
> > /sys/kernel/security/ima/policy.
> Perhaps I'm missing something, but current in this case should point
> to the process which is writing to the policy file, yes?
Yes, but current->context is NULL for some reason.