* Mickaël Salaün: > Being able to restrict execution also enables to protect the kernel by > restricting arbitrary syscalls that an attacker could perform with a > crafted binary or certain script languages. It also improves multilevel > isolation by reducing the ability of an attacker to use side channels > with specific code. These restrictions can natively be enforced for ELF > binaries (with the noexec mount option) but require this kernel > extension to properly handle scripts (e.g. Python, Perl). To get a > consistent execution policy, additional memory restrictions should also > be enforced (e.g. thanks to SELinux). One example I have come across recently is that code which can be safely loaded as a Perl module is definitely not a no-op as a shell script: it downloads code and executes it, apparently over an untrusted network connection and without signature checking. Maybe in the IMA world, the expectation is that such ambiguous code would not be signed in the first place, but general-purpose distributions are heading in a different direction with across-the-board signing: Signed RPM Contents <https://fedoraproject.org/wiki/Changes/Signed_RPM_Contents> So I wonder if we need additional context information for a potential LSM to identify the intended use case.
