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SubjectRe: [PATCH 0/4] selftests/sgx: Harden test enclave
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On Thu Jul 20, 2023 at 7:12 PM UTC, Jo Van Bulck wrote:
> On 20.07.23 19:25, Jarkko Sakkinen wrote:
> > There's a lot of source code in kselftest, which probably has at least
> > some security issues.
> >
> > I'm not sure, at least based on this motivation, why would we care?
>
> I'd argue that, in general, code examples are often used as templates
> and may thus inherit any vulnerabilities therein. This may be especially
> relevant here as your selftest enclave is in my knowledge the only
> available truly minimal SGX enclave that can be built and extended while
> only relying on standard tools and no heavy frameworks like the Intel
> SGX SDK. Thus, as noted before on this mailing list, it may be an
> attractive start for people who want to build things from scratch.

If you use this code as a template, you have a legal risk in your hands
because of GPLv2 licensing.

> IMHO the example enclave should do a best effort to reasonably follow
> SGX coding best practices and not have _known_ security vulnerabilities
> in it. Note that these are not advanced microarchitectural attacks with
> ugly LFENCE defenses, but plain, architectural memory-safety exploit
> preventions with minimal sanitization checks, not unlike the existing
> protections against buffer overflow where best practices are followed
> for op->type.

I'm not sure what are the "best practices" behavior in the context of a
kselftest instance.

> Apart from that, the added checks only enforce correct behavior in the
> test framework, only validating that things are sane and as expected.
> Thus, to some extent, the added checks may even increase resilience of
> the test framework.

I'm not sure what is "correct" behavior in the context of a kselftest
instance.

> Best,
> Jo

This code is not meant for production. I implemented it specifically for
kselftest, and that is exactly its scope.

BR, Jarkko

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