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

[Mimi Zohar]

On Tue, 2019-04-02 at 15:31 -0700, Matthew Garrett wrote:
> On Fri, Mar 29, 2019 at 5:50 AM Igor Zhbanov <i.zhbanov at omprussia.ru> wrote:
> > I want to be sure that no unsigned code page could be executed. So exploits
> > could only be of ROP kind and not being able to download any extra code
> > from their servers. That's why I found that disabling of anonymous executable
> > pages could be useful for that (as well as disabling of making executable
> > pages writable to modify already mapped code). In conjunction with IMA it
> > should guarantee that no untrusted code could be executed.
> 
> Remember that many interpreted languages allow execution of code
> provided to them on the command line (eg, python -c) and also grant
> access to arbitrary syscalls, so there's still no guarantee that
> you're only executing trusted code.

Interpreters are a known concern, as Yves-Alexis Perez pointed out in
his LSS-2018 Europe talk[1].

Mimi

[1] https://events.linuxfoundation.org/wp-content/uploads/2017/12/Linu
x-Kernel-Security-Contributions-by-ANSSI-Yves-Alexis-Perez-ANSSI.pdf