Code Review Rust

Rust source review

When it applies

Reviewing Rust (a service, a CLI, a library). Safe Rust removes most memory bugs, so the review focuses on the places safety is opted out of, the ways Rust code still panics or mis-handles input, and ordinary injection/logic in web handlers.

Why it works

Rust's guarantees hold only outside unsafe and only for memory safety — they don't stop SQL built by string, a command run via a shell, a .unwrap() that panics on attacker input (DoS), or a logic error. Concentrating on those boundaries finds the real bugs efficiently.

Sinks & patterns (grep, then reason about the boundary)

• unsafe blocks: every one is a manual proof obligation — raw pointer deref, get_unchecked, slice::from_raw_parts, mem::transmute, uninitialised memory. Check the invariant it assumes.
• FFI: extern "C"/bindgen boundaries — lengths, lifetimes, and NUL handling across the C edge (the C side has none of Rust's guarantees; pair with code-review-cpp).
• Panics as DoS: unwrap/expect/panic!/indexing v[i]/unreachable! on attacker-controlled input; integer as casts that truncate; arithmetic overflow (panics in debug, wraps in release — both can be bugs). Prefer ?/checked ops.
• Injection: SQL via format! into a query instead of parameter binding (sqlx/diesel); std::process::Command with sh -c and concatenated input; Command arg vs shell form.
• Path / SSRF: user paths joined without canonicalisation + prefix check; HTTP clients (reqwest) fetching user URLs.
• Deserialization / web: serde into types from untrusted data (resource exhaustion, unexpected variants); actix/axum/rocket extractors bound to over-broad structs (mass assignment); missing auth middleware on state-changing routes.

Method

1. Run cargo audit (known-vuln deps), cargo clippy, and semgrep; miri for unsafe UB where feasible.
2. rg 'unsafe|unwrap\(\)|expect\(|transmute|Command::new|format!\(.*(SELECT|INSERT|UPDATE)' → review each.
3. Justify every unsafe block's invariant; if you can't, that's a finding.
4. Confirm exploitable injection/logic with the matching runtime skill.

Gotchas

• Idiomatic Rust is genuinely safe — don't invent memory bugs in safe code; spend effort on unsafe, FFI, panics, deps, and logic.
• Release-mode integer overflow wraps silently — a checked_*/saturating_* audit matters for size/index math.
• cargo audit flags vulnerable crates you'd never see by reading — always run it.

References

Rustonomicon (unsafe); RustSec advisory DB / cargo-audit; Clippy lint set; Secure Rust Guidelines (ANSSI).