asupersync 0.3.4

//! ATP timing side-channel detection conformance tests.
//!
//! These tests validate the enhanced timing side-channel detection system
//! for ATP cryptographic operations. Uses hardware performance counters,
//! statistical analysis, and baseline calibration to detect subtle timing
//! variations that could leak cryptographic secrets.
//!
//! Addresses asupersync-5brfl0: Enhanced timing measurement precision.

#[cfg(test)]
mod tests {
    use crate::atp::timing_security::{
        SideChannelDetectionResult, TimingDetectorConfig, TimingSideChannelDetector,
    };
    use std::collections::HashMap;
    use std::thread;
    use std::time::Duration;

    type TimingConformanceCase = fn(&TimingSideChannelDetector) -> SideChannelDetectionResult;

    /// Mock ATP cryptographic operation for testing.
    struct MockCryptoOperation {
        key: [u8; 32],
        data_dependent_timing: bool,
    }

    impl MockCryptoOperation {
        fn new(key: [u8; 32], data_dependent_timing: bool) -> Self {
            Self {
                key,
                data_dependent_timing,
            }
        }

        /// Simulate cryptographic operation with optional timing leak.
        fn process(&self, data: &[u8]) -> Vec<u8> {
            let mut result = Vec::with_capacity(data.len());

            for &byte in data {
                // XOR with key byte
                let encrypted = byte ^ self.key[byte as usize % 32];
                result.push(encrypted);

                // Introduce data-dependent timing if enabled
                if self.data_dependent_timing && byte != 0 {
                    // Simulate additional work for non-zero bytes (timing leak)
                    let _work: u64 = (0..byte as u64).map(|x| x * x).sum();
                }
            }

            result
        }

        /// Constant-time implementation without timing leaks.
        fn process_constant_time(&self, data: &[u8]) -> Vec<u8> {
            let mut result = Vec::with_capacity(data.len());

            for &byte in data {
                // XOR with key byte
                let encrypted = byte ^ self.key[byte as usize % 32];
                result.push(encrypted);

                // Always do the same amount of work regardless of data
                let _work: u64 = (0..255u64).map(|x| x * x).sum();
            }

            result
        }
    }

    #[test]
    fn test_enhanced_timing_precision_baseline() {
        // Test that enhanced timing system can establish stable baseline
        let mut detector = TimingSideChannelDetector::new(TimingDetectorConfig {
            baseline_samples: 5000,
            significance_threshold: 0.01,
            min_suspicious_delta_ns: 50,
            max_baseline_cv: 0.15, // Allow slightly higher variance for mock operations
            warmup_iterations: 500,
        });

        let crypto_op = MockCryptoOperation::new([42u8; 32], false);
        let test_data = vec![0u8; 64];

        // Calibrate baseline with consistent operation
        let calibration_result = detector.calibrate_baseline(|| {
            let _result = crypto_op.process_constant_time(&test_data);
        });

        assert!(
            calibration_result.is_ok(),
            "Enhanced timing baseline calibration failed: {:?}",
            calibration_result
        );
    }

    #[test]
    fn test_tsc_timing_precision() {
        // Test that TSC-based timing provides higher precision than Duration
        let _detector = TimingSideChannelDetector::default();

        // Test very short operation timing precision
        let mut measurements = Vec::new();
        for _ in 0..1000 {
            let start = std::time::Instant::now();
            let _tiny_work = 2u64.pow(10); // Very small amount of work
            let duration_ns = start.elapsed().as_nanos() as u64;
            measurements.push(duration_ns);
        }

        // Enhanced system should provide sub-microsecond precision
        let avg_measurement: f64 =
            measurements.iter().map(|&x| x as f64).sum::<f64>() / measurements.len() as f64;

        // Should be able to measure operations faster than 10 microseconds
        assert!(
            avg_measurement < 10_000.0, // Less than 10μs
            "Enhanced timing precision insufficient: average {}ns",
            avg_measurement
        );
    }

    #[test]
    fn test_statistical_timing_analysis() {
        // Test statistical analysis capabilities for timing side-channel detection
        let detector = TimingSideChannelDetector::new(TimingDetectorConfig {
            baseline_samples: 3000,
            significance_threshold: 0.05,
            min_suspicious_delta_ns: 100,
            max_baseline_cv: 0.2,
            warmup_iterations: 300,
        });

        let safe_crypto = MockCryptoOperation::new([0x55u8; 32], false);
        let unsafe_crypto = MockCryptoOperation::new([0xAAu8; 32], true);

        let zero_data = vec![0u8; 32];
        let nonzero_data = vec![0x42u8; 32];

        // Test constant-time implementation (should pass)
        let safe_result = detector.test_constant_time(
            |data| {
                let _result = safe_crypto.process_constant_time(data);
            },
            &zero_data,
            &nonzero_data,
            2000,
        );

        assert!(
            !safe_result.detected,
            "False positive: detected timing leak in constant-time implementation: {}",
            safe_result.description
        );

        // Test vulnerable implementation (should detect timing leak)
        let vulnerable_result = detector.test_constant_time(
            |data| {
                let _result = unsafe_crypto.process(data);
            },
            &zero_data,
            &nonzero_data,
            2000,
        );

        assert!(
            vulnerable_result.detected,
            "Failed to detect timing vulnerability: {}",
            vulnerable_result.description
        );

        // Verify statistical significance
        assert!(
            vulnerable_result.p_value < 0.05,
            "Timing difference not statistically significant: p={}",
            vulnerable_result.p_value
        );
    }

    #[test]
    fn test_baseline_calibration_stability() {
        // Test that baseline calibration rejects unstable timing environments
        let mut detector = TimingSideChannelDetector::new(TimingDetectorConfig {
            baseline_samples: 1000,
            significance_threshold: 0.01,
            min_suspicious_delta_ns: 50,
            max_baseline_cv: 0.05, // Very strict variance requirement
            warmup_iterations: 100,
        });

        // Operation with intentionally high timing variance
        let unstable_operation = || {
            // Random additional work to create timing instability
            let work_factor = (std::time::SystemTime::now()
                .duration_since(std::time::SystemTime::UNIX_EPOCH)
                .unwrap()
                .as_nanos()
                % 100) as u64;
            let _work: u64 = (0..work_factor).sum();
        };

        let calibration_result = detector.calibrate_baseline(unstable_operation);

        // Should reject baseline with high coefficient of variation
        assert!(
            calibration_result.is_err(),
            "Should reject unstable baseline timing"
        );
    }

    #[test]
    fn test_atp_crypto_operations_constant_time() {
        // Test ATP cryptographic primitives for timing side-channels
        let detector = TimingSideChannelDetector::new(TimingDetectorConfig {
            baseline_samples: 2000,
            significance_threshold: 0.01,
            min_suspicious_delta_ns: 200,
            max_baseline_cv: 0.15,
            warmup_iterations: 500,
        });

        // Test common ATP cryptographic operations
        let test_cases = vec![
            (
                "hmac_computation",
                test_hmac_timing as TimingConformanceCase,
            ),
            (
                "key_derivation",
                test_key_derivation_timing as TimingConformanceCase,
            ),
            (
                "signature_verification",
                test_signature_timing as TimingConformanceCase,
            ),
        ];

        let mut results = HashMap::new();

        for (operation_name, test_fn) in test_cases {
            let result = test_fn(&detector);
            results.insert(operation_name.to_string(), result);
        }

        // Report all findings
        let mut vulnerabilities_found = 0;
        for (operation, result) in &results {
            if result.detected {
                println!(
                    "⚠️  Timing vulnerability detected in {}: {}",
                    operation, result.description
                );
                vulnerabilities_found += 1;
            } else {
                println!(
                    "✅ {} appears constant-time: {}",
                    operation, result.description
                );
            }
        }

        // ATP crypto operations should all be constant-time
        assert_eq!(
            vulnerabilities_found, 0,
            "Found {} timing vulnerabilities in ATP crypto operations",
            vulnerabilities_found
        );
    }

    fn test_hmac_timing(detector: &TimingSideChannelDetector) -> SideChannelDetectionResult {
        // Mock HMAC computation with different inputs
        let key = [0x5Au8; 32];
        let message_a = vec![0u8; 64]; // All zeros
        let message_b = vec![0xFFu8; 64]; // All ones

        detector.test_constant_time(
            |data| {
                // Simple mock HMAC computation
                let mut result = [0u8; 32];
                for (i, &byte) in data.iter().enumerate() {
                    result[i % 32] ^= byte.wrapping_add(key[i % 32]);
                }
            },
            &message_a,
            &message_b,
            1500,
        )
    }

    fn test_key_derivation_timing(
        detector: &TimingSideChannelDetector,
    ) -> SideChannelDetectionResult {
        // Mock key derivation with different salt values
        let salt_a = vec![0x00u8; 16];
        let salt_b = vec![0xFFu8; 16];

        detector.test_constant_time(
            |salt| {
                // Mock PBKDF2-style key derivation
                let mut derived_key = [0u8; 32];
                for round in 0..100 {
                    for (i, &salt_byte) in salt.iter().enumerate() {
                        derived_key[i % 32] ^= salt_byte.wrapping_add(round as u8);
                    }
                }
            },
            &salt_a,
            &salt_b,
            1000,
        )
    }

    fn test_signature_timing(detector: &TimingSideChannelDetector) -> SideChannelDetectionResult {
        // Mock signature verification with different signatures
        let valid_sig = vec![0x55u8; 64];
        let invalid_sig = vec![0xAAu8; 64];

        detector.test_constant_time(
            |signature| {
                // Mock signature verification (constant-time comparison)
                let expected = [0x55u8; 64];
                let mut mismatch = 0u8;
                for (i, &sig_byte) in signature.iter().enumerate() {
                    if i < expected.len() {
                        // Constant-time comparison
                        mismatch |= sig_byte ^ expected[i];
                    }
                }
                std::hint::black_box(mismatch == 0);
                // Always do same amount of work regardless of result
                let _dummy_work: u64 = (0..100).sum();
            },
            &valid_sig,
            &invalid_sig,
            1500,
        )
    }

    #[test]
    fn test_hardware_performance_counter_availability() {
        // Test detection of hardware timing sources
        let _detector = TimingSideChannelDetector::default();

        // Should be able to take high-resolution timing measurements
        let start = std::time::Instant::now();

        // Simulate timing measurement
        for _ in 0..10 {
            thread::sleep(Duration::from_nanos(1)); // Very short sleep
        }

        let elapsed_ns = start.elapsed().as_nanos() as u64;

        // Enhanced timing should provide better than microsecond precision
        assert!(
            elapsed_ns > 0,
            "Hardware timer should provide non-zero measurements"
        );
    }

    #[test]
    fn test_timing_attack_vector_coverage() {
        // Test coverage of known timing attack vectors
        let detector = TimingSideChannelDetector::new(TimingDetectorConfig {
            baseline_samples: 1500,
            significance_threshold: 0.01,
            min_suspicious_delta_ns: 100,
            max_baseline_cv: 0.2,
            warmup_iterations: 200,
        });

        // Attack vector 1: Early termination in string comparison
        let result_1 = test_early_termination_attack(&detector);
        assert!(
            result_1.detected,
            "Failed to detect early termination attack"
        );

        // Attack vector 2: Conditional branching based on secret data
        let result_2 = test_conditional_branching_attack(&detector);
        assert!(
            result_2.detected,
            "Failed to detect conditional branching attack"
        );

        // Attack vector 3: Cache timing through lookup tables
        let result_3 = test_cache_timing_attack(&detector);
        // Note: Cache attacks may not always be detectable in unit tests
        println!("Cache timing test result: {}", result_3.description);
    }

    fn test_early_termination_attack(
        detector: &TimingSideChannelDetector,
    ) -> SideChannelDetectionResult {
        let secret_prefix = b"SECRET_";
        let guess_correct = b"SECRET_PASSWORD";
        let guess_wrong = b"WRONG_PASSWORD";

        detector.test_constant_time(
            |guess| {
                // Vulnerable comparison that terminates early on first mismatch
                for (i, &guess_byte) in guess.iter().enumerate() {
                    if i >= secret_prefix.len() {
                        break;
                    }
                    if guess_byte != secret_prefix[i] {
                        return; // Early termination = timing leak
                    }
                }
            },
            guess_correct,
            guess_wrong,
            2000,
        )
    }

    fn test_conditional_branching_attack(
        detector: &TimingSideChannelDetector,
    ) -> SideChannelDetectionResult {
        let high_entropy_data = b"ABCDEFGHIJKLMNOP";
        let low_entropy_data = b"AAAAAAAAAAAAAAAA";

        detector.test_constant_time(
            |data| {
                let mut work = 0u64;
                for &byte in data {
                    // Conditional branching based on data content
                    if byte & 1 == 0 {
                        // Even bytes: more work
                        work += (0..100).map(|x| x * byte as u64).sum::<u64>();
                    } else {
                        // Odd bytes: less work
                        work += byte as u64;
                    }
                }
                // Prevent optimization
                std::hint::black_box(work);
            },
            high_entropy_data,
            low_entropy_data,
            1500,
        )
    }

    fn test_cache_timing_attack(
        detector: &TimingSideChannelDetector,
    ) -> SideChannelDetectionResult {
        // Simplified cache timing test (difficult to reproduce reliably in unit tests)
        let cache_friendly_data = vec![0u8; 64];
        let cache_unfriendly_data: Vec<u8> = (0..64).map(|i| (i * 37) as u8).collect();

        detector.test_constant_time(
            |data| {
                // Simulate lookup table access pattern
                let lookup_table = [0u64; 256];
                let mut result = 0u64;
                for &byte in data {
                    result ^= lookup_table[byte as usize];
                }
                std::hint::black_box(result);
            },
            &cache_friendly_data,
            &cache_unfriendly_data,
            2000,
        )
    }
}