Should mprotect(..., PROT_EXEC) be checked by IMA?

[Stephen Smalley]

On 3/29/19 6:59 AM, Mimi Zohar wrote:
> [Cc'ing the LSM mailing list and others]
> 
> On Fri, 2019-03-29 at 13:00 +0300, Igor Zhbanov wrote:
>> Hi Mimi,On 28.03.2019 20:17, Mimi Zohar wrote:
> 
>>> I just came across the grsecurity article on mprotect.[1]
>>>   Has anyone looked at it? Would it make sense to make it a minor LSM?
>>>
>>> [1]https://pax.grsecurity.net/docs/mprotect.txt
>>
>> Interesting article. It is almost exactly of what I wanted to be implemented.
>>
>> If this minor LSM would be stackable to allow combining with e.g. SELinux
>> then why not.
> 
> Stacking shouldn't be a problem.  Other LSMs are already on the
> mprotect hook.  Let's hear what others think.

SELinux already provides a set of controls over executable mappings; see 
selinux_mmap_file and selinux_file_mprotect. Other major security 
modules may do likewise but I can't speak to that. Is there some gap you 
are trying to address that isn't already covered, or are you just trying 
to provide such restrictions without requiring one of the major modules?