Combine PRK and IDK_S generation VTL calls

[Angelina Vu (athvu)]

No description provided.

[Sangho Lee (sangho2)]

Hi Angelina,

Thank you for your effort! I have one recommendation: rather than modifying the fill_bytes_crng interface in the litebox crate, could you install a trusted seed throughVtl1Gate (e.g., set a new global var) and use that seed in LVBS's fill_bytes_crng implementation? As you already observed, the litebox crate is a shared common interface/abstraction. any changes of it affect many other subsystems, such that we require strong justification.

[github-actions]

🤖 SemverChecks 🤖 ⚠️ Potential breaking API changes detected ⚠️

Click for details

--- failure enum_variant_added: enum variant added on exhaustive enum ---

Description:
A publicly-visible enum without #[non_exhaustive] has a new variant.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#enum-variant-new
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/enum_variant_added.ron

Failed in:
  variant VsmFunction:ExchangeSecrets in /home/runner/work/litebox/litebox/litebox_common_lvbs/src/lib.rs:79

--- failure enum_variant_missing: pub enum variant removed or renamed ---

Description:
A publicly-visible enum has at least one variant that is no longer available under its prior name. It may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/enum_variant_missing.ron

Failed in:
  variant VsmFunction::SetPlatformRootKey, previously in file /home/runner/work/litebox/litebox/target/semver-checks/git-main/6e21ee1f8110d60a251b3057c5092d1ec6161a18/litebox_common_lvbs/src/lib.rs:79
  variant VsmFunction::GenerateIdentitySigningKey, previously in file /home/runner/work/litebox/litebox/target/semver-checks/git-main/6e21ee1f8110d60a251b3057c5092d1ec6161a18/litebox_common_lvbs/src/lib.rs:80

--- failure pub_module_level_const_missing: pub module-level const is missing ---

Description:
A public const is missing or renamed
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/pub_module_level_const_missing.ron

Failed in:
  VSM_VTL_CALL_FUNC_ID_GENERATE_IDENTITY_SIGNING_KEY in file /home/runner/work/litebox/litebox/target/semver-checks/git-main/6e21ee1f8110d60a251b3057c5092d1ec6161a18/litebox_common_lvbs/src/lib.rs:55
  VSM_VTL_CALL_FUNC_ID_SET_PLATFORM_ROOT_KEY in file /home/runner/work/litebox/litebox/target/semver-checks/git-main/6e21ee1f8110d60a251b3057c5092d1ec6161a18/litebox_common_lvbs/src/lib.rs:52

--- failure trait_method_added: pub trait method added ---

Description:
A non-sealed public trait added a new method without a default implementation, which breaks downstream implementations of the trait
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#trait-new-item-no-default
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/trait_method_added.ron

Failed in:
  trait method litebox_common_lvbs::Vtl1Gate::set_crng_seed in file /home/runner/work/litebox/litebox/litebox_common_lvbs/src/lib.rs:973

[Sangho Lee (sangho2)]

Overall, looks good to me. I left some comments and suggestion.

[Sangho Lee (sangho2)]

tpm -> rot/hrot?

It'd be better to use &[u8; CRNG_SEED_LEN].

[Sangho Lee (sangho2)]

nits: let's use checked_add to catch integer overflow.

[Sangho Lee (sangho2)]

seed: &[u8; CRNG_SEED_LEN] would be better.

[Sangho Lee (sangho2)]

This depends on the ABI, but, at least for now, separating set_platform_root_key and set_crng_seed is a bit bad for performance and atomicity (redundant page mapping/copying and potential partial failure). That is, we can copy 64 bytes at once, rather than copy two 32 bytes in order. Anyway, it depends on VTL0-side argument passing, so it's up to you.