parlov-elicit 0.1.0

//! `OversizedBodyElicitation` — probes with a spoofed `Content-Length` declaring 10 MB.
//!
//! Sends `Content-Length: 10485760` on the probe request with a small actual
//! body. Servers that enforce payload size limits before existence-checking
//! return 413 for a resource that exists (size rejected early) versus 404 for
//! a nonexistent one (existence check short-circuits before size validation).
//! Both sides carry `Content-Type: application/json`.

use http::Method;

use crate::strategy::Strategy;
use crate::types::{ProbeSpec, RiskLevel, StrategyMetadata};
use crate::util::{build_pair, clone_headers_with, json_body};
use crate::ScanContext;

/// Declared body size for the probe — 10 MiB, never actually sent.
const SPOOFED_CONTENT_LENGTH: &str = "10485760";

fn metadata() -> StrategyMetadata {
    StrategyMetadata {
        strategy_id: "oversized-body-elicit",
        strategy_name: "Oversized Body Elicitation",
        risk: RiskLevel::MethodDestructive,
    }
}

/// Elicits existence differentials by spoofing a large `Content-Length` on probe requests.
pub struct OversizedBodyElicitation;

impl Strategy for OversizedBodyElicitation {
    fn id(&self) -> &'static str {
        "oversized-body-elicit"
    }

    fn name(&self) -> &'static str {
        "Oversized Body Elicitation"
    }

    fn risk(&self) -> RiskLevel {
        RiskLevel::MethodDestructive
    }

    fn methods(&self) -> &[Method] {
        &[Method::POST, Method::PUT, Method::PATCH]
    }

    fn is_applicable(&self, _ctx: &ScanContext) -> bool {
        true
    }

    fn generate(&self, ctx: &ScanContext) -> Vec<ProbeSpec> {
        let body = Some(json_body(&[]));
        let mut specs = Vec::with_capacity(3);
        for method in [Method::POST, Method::PUT, Method::PATCH] {
            let baseline_headers =
                clone_headers_with(&ctx.headers, "content-type", "application/json");
            let probe_headers = clone_headers_with(
                &clone_headers_with(&ctx.headers, "content-type", "application/json"),
                "content-length",
                SPOOFED_CONTENT_LENGTH,
            );
            let pair = build_pair(
                ctx,
                method,
                baseline_headers,
                probe_headers,
                body.clone(),
                metadata(),
            );
            specs.push(ProbeSpec::Pair(pair));
        }
        specs
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use http::{HeaderMap, Method};

    fn make_ctx() -> ScanContext {
        ScanContext {
            target: "https://api.example.com/users/{id}".to_string(),
            baseline_id: "1001".to_string(),
            probe_id: "9999".to_string(),
            headers: HeaderMap::new(),
            max_risk: RiskLevel::MethodDestructive,
            known_duplicate: None,
            state_field: None,
            alt_credential: None,
        }
    }

    #[test]
    fn risk_is_method_destructive() {
        assert_eq!(OversizedBodyElicitation.risk(), RiskLevel::MethodDestructive);
    }

    #[test]
    fn methods_contains_post_put_patch() {
        let methods = OversizedBodyElicitation.methods();
        assert_eq!(methods.len(), 3);
        assert!(methods.contains(&Method::POST));
        assert!(methods.contains(&Method::PUT));
        assert!(methods.contains(&Method::PATCH));
    }

    #[test]
    fn is_applicable_always_true() {
        assert!(OversizedBodyElicitation.is_applicable(&make_ctx()));
    }

    #[test]
    fn generate_returns_three_items() {
        assert_eq!(OversizedBodyElicitation.generate(&make_ctx()).len(), 3);
    }

    #[test]
    fn probe_has_spoofed_content_length() {
        let specs = OversizedBodyElicitation.generate(&make_ctx());
        let ProbeSpec::Pair(pair) = &specs[0] else { panic!("expected Pair") };
        assert_eq!(
            pair.probe.headers.get("content-length").unwrap(),
            "10485760"
        );
    }

    #[test]
    fn baseline_lacks_content_length_header() {
        let specs = OversizedBodyElicitation.generate(&make_ctx());
        let ProbeSpec::Pair(pair) = &specs[0] else { panic!("expected Pair") };
        assert!(pair.baseline.headers.get("content-length").is_none());
    }

    #[test]
    fn both_have_application_json_content_type() {
        let specs = OversizedBodyElicitation.generate(&make_ctx());
        let ProbeSpec::Pair(pair) = &specs[0] else { panic!("expected Pair") };
        assert_eq!(
            pair.baseline.headers.get("content-type").unwrap(),
            "application/json"
        );
        assert_eq!(
            pair.probe.headers.get("content-type").unwrap(),
            "application/json"
        );
    }

    #[test]
    fn both_have_body() {
        let specs = OversizedBodyElicitation.generate(&make_ctx());
        let ProbeSpec::Pair(pair) = &specs[0] else { panic!("expected Pair") };
        assert!(pair.baseline.body.is_some());
        assert!(pair.probe.body.is_some());
    }
}