Select JWT crypto backend and add deterministic token tests

[chipp]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @chipp, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refactors the JWT token handling to improve testability and explicitly select a cryptographic backend. By introducing functions that allow for injecting secrets and timestamps, the token creation and validation logic can now be tested deterministically. This change also enables the rust_crypto feature of the jsonwebtoken crate, ensuring a pure Rust implementation for cryptographic operations and updating the dependency tree accordingly.

Highlights

• Cryptographic Backend Selection: Enabled the rust_crypto feature for the jsonwebtoken crate, transitioning to a pure Rust cryptographic implementation for JWT operations.
• Deterministic Token Testing: Introduced new internal functions for JWT creation and validation that accept an explicit secret and timestamp, allowing for predictable and deterministic testing of token logic.
• Custom Expiration Validation: Modified the JWT validation process to manually check token expiration, disabling the jsonwebtoken crate's default exp validation to facilitate deterministic testing.
• Comprehensive Unit Tests: Added a suite of unit tests for JWT tokens, covering various scenarios such as valid tokens, token type mismatches, expiration, and incorrect secrets.
• Dependency Updates: Updated Cargo.lock to include numerous new cryptographic dependencies required by the rust_crypto feature, reflecting the change in the underlying crypto implementation.

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Changelog

• Cargo.lock
  • Added new dependencies required by the rust_crypto feature, including base16ct, base64ct, const-oid, crypto-bigint, curve25519-dalek, der, ecdsa, ed25519, ed25519-dalek, elliptic-curve, ff, fiat-crypto, group, hkdf, hmac, libm, num-bigint-dig, num-iter, p256, p384, pem-rfc7468, pkcs1, pkcs8, primeorder, rand, rand_chacha, rfc6979, rsa, rustc_version, sec1, spin, spki, and zeroize.
• bin/alisa/Cargo.toml
  • Configured the jsonwebtoken dependency to explicitly use its rust_crypto feature.
• bin/alisa/src/web_service/auth/token.rs
  • Refactored is_valid_token and create_token_with_expiration_in into new internal functions (is_valid_token_with_secret, is_valid_token_with_secret_at, create_token_with_expiration_in_with_secret, create_token_with_expiration_in_with_secret_at) to allow for deterministic testing.
  • Modified JWT validation to disable automatic exp validation and perform it manually.
  • Changed the exp field in the Claims struct from usize to u64.
  • Added a current_timestamp helper function.
  • Implemented a new test module with unit tests for token validation and creation under various conditions.

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[gemini-code-assist]

Code Review

This pull request refactors the JWT token generation and validation logic to be deterministic and adds comprehensive tests, significantly improving testability. It also switches to the rust_crypto backend for jsonwebtoken, modifies the exp claim type to u64, and explicitly uses the HS512 algorithm. A security audit confirmed that these changes, including manual expiration checks, algorithm security, audience/subject validation, and secret handling, are well-implemented and introduce no new security risks. However, I've left a few comments regarding RFC compliance for token expiration, error handling, and robustness against panics.

[gemini-code-assist]

According to RFC 7519, the exp (expiration time) claim identifies the expiration time 'on or after which the JWT MUST NOT be accepted for processing'. This means the token is invalid if the current time is greater than or equal to the expiration time. The check should be decoded.claims.exp > now_timestamp to be compliant.

Note that the token_expires_exactly_at_expected_time test will need to be adjusted to reflect this change. For a token expiring at NOW + 30, it should be valid at NOW + 29 but invalid at NOW + 30.

    decoded.claims.exp > now_timestamp

[gemini-code-assist]

When token decoding fails, the error is currently ignored. It would be beneficial for debugging to log the error. This can help diagnose issues with malformed tokens, signature mismatches, or other validation problems.

    ) {
        Ok(decoded) => decoded,
        Err(e) => {
            log::debug!("Token decoding failed: {}", e);
            return false;
        }
    };

[gemini-code-assist]

The use of expect() here can cause the service to panic if an invalid expiration duration is provided (e.g., one that causes a timestamp overflow or underflow resulting in a negative value). While the current usage in the codebase is with constant durations, it's more robust for public functions and their helpers to return a Result instead of panicking. This would allow callers to handle such errors gracefully instead of crashing the thread.