Re: [PATCH v9 5/8] ima: make process_buffer_measurement() generic

[Lakshmi Ramasubramanian]

On 10/25/2019 10:24 AM, Nayna Jain wrote:
> On 10/24/19 10:20 AM, Lakshmi Ramasubramanian wrote:
> > On 10/23/19 8:47 PM, Nayna Jain wrote:
> >
> > Hi Nayna,
> >
> > > +void process_buffer_measurement(const void *buf, int size,
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ const char *eventname, enum ima_hooks func,
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ int pcr)
> > > Â {
> > > ÂÂÂÂÂ int ret = 0;
> > > ÂÂÂÂÂ struct ima_template_entry *entry = NULL;
> >
> > > +ÂÂÂ if (func) {
> > > +ÂÂÂÂÂÂÂ security_task_getsecid(current, &secid);
> > > +ÂÂÂÂÂÂÂ action = ima_get_action(NULL, current_cred(), secid, 0, func,
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ &pcr, &template);
> > > +ÂÂÂÂÂÂÂ if (!(action & IMA_MEASURE))
> > > +ÂÂÂÂÂÂÂÂÂÂÂ return;
> > > +ÂÂÂ }
> >
> > In your change set process_buffer_measurement is called with NONE for 
> > the parameter func. So ima_get_action (the above if block) will not be 
> > executed.
> >
> > Wouldn't it better to update ima_get_action (and related functions) to 
> > handle the ima policy (func param)?
>
>
> The idea is to use ima-buf template for the auxiliary measurement 
> record. The auxiliary measurement record is an additional record to the 
> one already created based on the existing policy. When func is passed as 
> NONE, it represents it is an additional record. I am not sure what you 
> mean by updating ima_get_action, it is already handling the ima policy.

I was referring to using "func" in process_buffer_measurement to 
determine ima action. In my opinion, process_buffer_measurement should 
be generic.

ima_get_action() should instead determine the required ima action, 
template, pcr, etc. based on "func" passed to it.

thanks,
 -lakshmi