On 2020-12-24 6:29 a.m., Mimi Zohar wrote:

Hi Tushar,

On Sat, 2020-12-12 at 10:02 -0800, Tushar Sugandhi wrote:

quoted

System administrators should be able to limit which kernel subsystems
they want to measure the critical data for. To enable that, an IMA policy
condition to choose specific kernel subsystems is needed. This policy
condition would constrain the measurement of the critical data based on
a label for the given subsystems.

Restricting which kernel integrity critical data is measured is not
only of interest to system administrators.   Why single them out?

system administrators are usually responsible for system 
policies/configurations.They own modifications in the config files like
ima-policy. That's why we wanted to address them to begin with. But you
are correct. This is not only of interest to sysadmins. I will make the 
description more generic.

Limiting which critical data is measured is based on a label, making it
flexible.  In your use case scenario, you're grouping the label based
on kernel subsystem, but is that really necessary?  In the broader
picture, there could be cross subsystem critical data being measured
based on a single label.

Please think about the broader picture and re-write the patch
descirption more generically.

Makes sense. Will make the patch description more generic.

quoted

Add a new IMA policy condition - "data_source:=" to the IMA func

What is with "add"?  You're "adding support for" or "defining" a new
policy condition.  Remove the single hyphen, as explained in 3/8.

Please replace "data_source" with something more generic (e.g. label).

Sounds good. Would you prefer "label" or something else like "data_label"?

In the policy file the "label" looks logical and more generic than 
"data_label".
    measure func=CRITICAL_DATA label=selinux

For the time being, I will stick with "label", please let me know if you
prefer something else.

Thanks,
Tushar

thanks,

Mimi

quoted

CRITICAL_DATA to allow measurement of various kernel subsystems. This
policy condition would enable the system administrators to restrict the
measurement to the labels listed in "data_source:=".

Limit the measurement to the labels that are specified in the IMA
policy - CRITICAL_DATA+"data_source:=". If "data_sources:=" is not
provided with the func CRITICAL_DATA, the data from all the
supported kernel subsystems is measured.

Signed-off-by: Tushar Sugandhi <redacted>