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android / platform / external / rust / crates / coset / refs/heads/android13-d1-s3-release
commit7f94e13246ed15845e5dbaea41bffd1f0f320267[log] [tgz]
authorAndroid Build Coastguard Worker <android-build-coastguard-worker@google.com>Fri Mar 04 01:04:39 2022 +0000
committerAndroid Build Coastguard Worker <android-build-coastguard-worker@google.com>Fri Mar 04 01:04:39 2022 +0000
treec59a2e47aff325e9bba41815f4fff46748663b0e
parent0a4351496b341298647e5695987468b70a266a96 [diff]
parent5e51be81e1dd965daebf1c13a5fd76a0ec09738e [diff]
Snap for 8249732 from 5e51be81e1dd965daebf1c13a5fd76a0ec09738e to tm-d1-release

Change-Id: I0ee3b4d8abb20ccbecfd5f6117f71a0fe1b60255
tree: c59a2e47aff325e9bba41815f4fff46748663b0e
  1. .github/
  2. examples/
  3. patches/
  4. scripts/
  5. src/
  6. .cargo_vcs_info.json
  7. .codecov.yml
  8. .gitignore
  9. .mdl-style.rb
  10. .mdlrc
  11. .rustfmt.toml
  12. Android.bp
  13. AUTHORS
  14. Cargo.lock
  15. Cargo.toml
  16. Cargo.toml.orig
  17. CHANGELOG.md
  18. CONTRIBUTING.md
  19. deny.toml
  20. dependabot.yml
  21. LICENSE
  22. METADATA
  23. MODULE_LICENSE_APACHE2
  24. OWNERS
  25. README.md
  26. TEST_MAPPING
README.md

COSET

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This crate holds a set of Rust types for working with CBOR Object Signing and Encryption (COSE) objects, as defined in RFC 8152. It builds on the core CBOR parsing functionality from the ciborium crate.

See crate docs, or the signature example for documentation on how to use the code.

This repo is under construction and so details of the API and the code may change without warning.

no_std Support

This crate supports no_std, but uses the alloc crate.

Minimum Supported Rust Version

MSRV is 1.56 (the main ciborium dependency is edition="2021")

Integer Ranges

CBOR supports integers in the range:

[-18_446_744_073_709_551_616, -1] ∪ [0, 18_446_744_073_709_551_615]

which is [-264, -1] ∪ [0, 264 - 1].

This does not map onto a single Rust integer type, so different CBOR crates take different approaches.

  • The serde_cbor crate uses a single i128 integer type for all integer values, which means that all CBOR integer values can be expressed, but there are also i128 values that cannot be encoded in CBOR. This also means that data size is larger.
  • The ciborium also uses a single i128 integer type internally, but wraps it in its own Integer type and only implements TryFrom (not From) for i128 / u128 conversions so that unrepresentable numbers can be rejected.
  • The sk-cbor crate uses distinct types:
    • positive numbers as u64, covering [0, 264 - 1]
    • negative numbers as i64, covering [-263, -1] (which means that some theoretically-valid large negative values are not represented).

This crate uses a single type to encompass both positive and negative values, but uses i64 for that type to keep data sizes smaller. This means that:

  • positive numbers in i64 cover [0, 263 - 1]
  • negative numbers in i64 cover [-263, -1]

and so there are large values – both positive and negative – which are not supported by this crate.

Working on the Code

Local coding conventions are enforced by the continuous integration jobs and include:

  • Build cleanly and pass all tests.
  • Free of Clippy warnings.
  • Formatted with rustfmt using the local rustfmt.toml settings.
  • Compliance with local conventions:
    • All TODO markers should be of form TODO(#99) and refer to an open GitHub issue.
    • Calls to functions that can panic (panic!, unwrap, expect) should have a comment on the same line in the form // safe: reason (or /* safe: reason */) to document the reason why panicking is acceptable.

Disclaimer

This is not an officially supported Google product.