On Mon, Aug 19, 2024 at 09:05:47PM +0300, Jarkko Sakkinen wrote: > On Fri Aug 16, 2024 at 9:41 PM EEST, Matthew Garrett wrote: > > On Fri, Aug 16, 2024 at 02:22:04PM +0300, Jarkko Sakkinen wrote: > > > > > For (any) non-legacy features we can choose, which choices we choose to > > > support, and which we do not. This is not an oppositive view just saying > > > how it is, and platforms set of choices is not a selling argument. > > > > NIST still permits the use of SHA-1 until 2030, and the most significant > > demonstrated weaknesses in it don't seem applicable to the use case > > here. We certainly shouldn't encourage any new uses of it, and anyone > > who's able to use SHA-2 should be doing that instead, but it feels like > > people are arguing about not supporting hardware that exists in the real > > world for vibes reasons rather than it being a realistically attackable > > weakness (and if we really *are* that concerned about SHA-1, why are we > > still supporting TPM 1.2 at all?) > > We are life-supporting TPM 1.2 as long as necessary but neither the > support is extended nor new features will gain TPM 1.2 support. So > that is at least my policy for that feature. But the fact that we support it and provide no warning labels is a pretty clear indication that we're not actively trying to prevent people from using SHA-1 in the general case. Why is this a different case? Failing to support it actually opens an entire separate set of footgun opportunities in terms of the SHA-1 banks now being out of sync with the SHA-2 ones, so either way we're leaving people open to making poor choices.
