parlov-elicit 0.3.0

//! `UniquenessElicitation` -- probes with a body that triggers a uniqueness conflict.
//!
//! Sends a JSON body containing a known-duplicate field value (from `ctx.known_duplicate`)
//! on both baseline and probe requests. The oracle signal is the server returning 409
//! versus 404 for a nonexistent one.

use http::Method;
use parlov_core::{NormativeStrength, OracleClass, Technique, Vector};

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

fn metadata() -> StrategyMetadata {
    StrategyMetadata {
        strategy_id: "uniqueness-elicit",
        strategy_name: "Uniqueness Elicitation",
        risk: RiskLevel::OperationDestructive,
    }
}

fn technique() -> Technique {
    Technique {
        id: "uniqueness",
        name: "Uniqueness conflict probe",
        oracle_class: OracleClass::Existence,
        vector: Vector::StatusCodeDiff,
        strength: NormativeStrength::May,
    }
}

/// Elicits existence differentials via a uniqueness-conflict body payload.
pub struct UniquenessElicitation;

impl Strategy for UniquenessElicitation {
    fn id(&self) -> &'static str {
        "uniqueness-elicit"
    }

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

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

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

    fn is_applicable(&self, ctx: &ScanContext) -> bool {
        ctx.known_duplicate.is_some()
    }

    fn generate(&self, ctx: &ScanContext) -> Vec<ProbeSpec> {
        let Some(kd) = &ctx.known_duplicate else { return vec![] };
        let body = Some(json_body(&[(&kd.field, &kd.value)]));
        let headers = clone_headers_with(&ctx.headers, "content-type", "application/json");
        let mut specs = Vec::with_capacity(2);
        for method in [Method::POST, Method::PUT] {
            let pair = build_pair(
                ctx, method, headers.clone(), headers.clone(),
                body.clone(), metadata(), technique(),
            );
            specs.push(ProbeSpec::Pair(pair));
        }
        specs
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::KnownDuplicate;
    use http::HeaderMap;

    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::OperationDestructive,
            known_duplicate: None,
            state_field: None,
            alt_credential: None,
            body_template: None,
        }
    }

    fn make_ctx_with_duplicate() -> ScanContext {
        ScanContext {
            known_duplicate: Some(KnownDuplicate {
                field: "email".to_string(),
                value: "alice@example.com".to_string(),
            }),
            ..make_ctx()
        }
    }

    #[test]
    fn risk_is_operation_destructive() {
        assert_eq!(UniquenessElicitation.risk(), RiskLevel::OperationDestructive);
    }

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

    #[test]
    fn is_applicable_true_when_known_duplicate_some() {
        assert!(UniquenessElicitation.is_applicable(&make_ctx_with_duplicate()));
    }

    #[test]
    fn generate_returns_two_items_when_applicable() {
        assert_eq!(UniquenessElicitation.generate(&make_ctx_with_duplicate()).len(), 2);
    }

    #[test]
    fn probe_body_contains_duplicate_field() {
        let specs = UniquenessElicitation.generate(&make_ctx_with_duplicate());
        let ProbeSpec::Pair(pair) = &specs[0] else { panic!("expected Pair") };
        let body = pair.probe.body.as_deref().expect("body must be present");
        let parsed: serde_json::Value = serde_json::from_slice(body).expect("valid JSON");
        assert_eq!(parsed["email"], "alice@example.com");
    }

    #[test]
    fn technique_strength_is_may() {
        let specs = UniquenessElicitation.generate(&make_ctx_with_duplicate());
        assert_eq!(specs[0].technique().strength, NormativeStrength::May);
    }
}