Module scanner 

Content-safety gate for downloaded files — a small, pure-Rust “antivirus”.

Anything fetched from the open web is untrusted, so before a downloaded file is handed back to a caller it passes three checks, cheapest first:

1. size cap — reject anything over the configured ceiling; an unbounded download is itself a resource-exhaustion surface.
2. magic-byte sniff (infer) — detect the file’s real type from its bytes. A file whose bytes are an executable but whose claimed Content-Type is a benign document (PDF, image, …) is a classic disguised-payload and is flagged.
3. signature scan (yara_x) — VirusTotal’s pure-Rust YARA engine, run against a tiny embedded ruleset. Ships an EICAR signature so the gate is testable with the industry-standard harmless test file.

clamd signature-database scanning is intentionally not here — it needs an external daemon and is an opt-in follow-up. This module is the always-on baseline that runs anywhere, including CI.

Structs

ScanConfig

Knobs for scan_bytes / scan_path.

ScanReport

Outcome of a scan.

Enums

Verdict

Verdict for a scanned buffer.

Constants

DEFAULT_MAX_BYTES

Default size ceiling: 100 MiB. Downloads larger than this are rejected before any scan.

Functions

scan_bytes

Scan an in-memory buffer. Infallible — every failure mode is expressed as a Verdict::Flagged rather than an error, so the gate never silently lets a file through on a scanner hiccup.

scan_path

Read path and scan its contents. See scan_bytes.