安全模型¶

pub struct RiskAssessment {
    data_sensitivity: f32,      // 0.0 = public, 1.0 = top secret
    code_trust_level: f32,      // 0.0 = untrusted, 1.0 = verified
    network_access: bool,       // Requires external network
    filesystem_access: bool,    // Requires filesystem write
    external_apis: bool,        // Uses external services
}

pub fn calculate_risk_score(assessment: RiskAssessment) -> f32 {
    let base_score = assessment.data_sensitivity * 0.4
        + (1.0 - assessment.code_trust_level) * 0.3;

    let access_penalty = if assessment.network_access { 0.1 } else { 0.0 }
        + if assessment.filesystem_access { 0.1 } else { 0.0 }
        + if assessment.external_apis { 0.1 } else { 0.0 };

    (base_score + access_penalty).min(1.0)
}

policy secure_data_access {
    allow: read(sensitive_data) if (
        user.clearance >= "secret" &&
        user.need_to_know.contains(data.classification) &&
        session.mfa_verified == true
    )

    deny: export(data) if data.contains_pii == true

    require: [
        user.background_check.current,
        session.secure_connection,
        audit_trail = "detailed"
    ]
}

policy data_flow_control {
    allow: transform(data) if (
        source.classification <= target.classification &&
        user.transform_permissions.contains(operation.type)
    )

    deny: aggregate(datasets) if (
        any(datasets, |d| d.privacy_level > operation.privacy_budget)
    )

    require: differential_privacy for statistical_operations
}

policy resource_governance {
    allow: allocate(resources) if (
        user.resource_quota.remaining >= resources.total &&
        operation.priority <= user.max_priority
    )

    deny: long_running_operations if system.maintenance_mode

    require: supervisor_approval for high_memory_operations
}

pub trait PolicyEngine {
    async fn evaluate_policy(
        &self,
        context: PolicyContext,
        action: Action
    ) -> PolicyDecision;

    async fn register_policy(&self, policy: Policy) -> Result<PolicyId>;
    async fn update_policy(&self, policy_id: PolicyId, policy: Policy) -> Result<()>;
}

pub enum PolicyDecision {
    Allow,
    Deny { reason: String },
    AllowWithConditions { conditions: Vec<PolicyCondition> },
    RequireApproval { approver: String },
}

use symbi_runtime::reasoning::cedar_gate::CedarPolicyGate;

// Create a Cedar policy gate with deny-by-default stance
let cedar_gate = CedarPolicyGate::deny_by_default();
let runner = ReasoningLoopRunner::builder()
    .provider(provider)
    .executor(executor)
    .policy_gate(Arc::new(cedar_gate))
    .build();

pub struct MessageSignature {
    pub signature: Vec<u8>,
    pub algorithm: SignatureAlgorithm,
    pub public_key: Vec<u8>,
}

impl AuditEvent {
    pub fn sign(&mut self, private_key: &PrivateKey) -> Result<()> {
        let message = self.serialize_for_signing()?;
        self.signature = private_key.sign(&message);
        Ok(())
    }

    pub fn verify(&self, public_key: &PublicKey) -> bool {
        let message = self.serialize_for_signing().unwrap();
        public_key.verify(&message, &self.signature)
    }
}

pub struct KeyManager {
    hsm: HardwareSecurityModule,
    key_store: SecureKeyStore,
    rotation_policy: KeyRotationPolicy,
}

impl KeyManager {
    pub async fn generate_agent_keys(&self, agent_id: AgentId) -> Result<KeyPair>;
    pub async fn rotate_keys(&self, key_id: KeyId) -> Result<KeyPair>;
    pub async fn revoke_key(&self, key_id: KeyId) -> Result<()>;
}

pub fn encrypt_message(
    plaintext: &[u8],
    recipient_public_key: &PublicKey,
    sender_private_key: &PrivateKey
) -> Result<EncryptedMessage> {
    let shared_secret = sender_private_key.diffie_hellman(recipient_public_key);
    let nonce = generate_random_nonce();
    let ciphertext = ChaCha20Poly1305::new(&shared_secret)
        .encrypt(&nonce, plaintext)?;

    Ok(EncryptedMessage {
        nonce,
        ciphertext,
        sender_public_key: sender_private_key.public_key(),
    })
}

pub struct AuditEvent {
    pub event_id: Uuid,
    pub timestamp: SystemTime,
    pub agent_id: AgentId,
    pub event_type: AuditEventType,
    pub details: serde_json::Value,
    pub signature: Ed25519Signature,
    pub previous_hash: Hash,
    pub event_hash: Hash,
}

impl AuditChain {
    pub fn append_event(&mut self, mut event: AuditEvent) -> Result<()> {
        event.previous_hash = self.last_hash;
        event.event_hash = self.calculate_event_hash(&event);
        event.sign(&self.signing_key)?;

        self.events.push(event.clone());
        self.last_hash = event.event_hash;

        self.verify_chain_integrity()?;
        Ok(())
    }

    pub fn verify_integrity(&self) -> Result<bool> {
        for (i, event) in self.events.iter().enumerate() {
            // Verify signature
            if !event.verify(&self.public_key) {
                return Ok(false);
            }

            // Verify hash chain
            if i > 0 && event.previous_hash != self.events[i-1].event_hash {
                return Ok(false);
            }
        }
        Ok(true)
    }
}

pub struct ComplianceFramework {
    pub name: String,
    pub audit_requirements: Vec<AuditRequirement>,
    pub retention_policy: RetentionPolicy,
    pub access_controls: Vec<AccessControl>,
    pub data_protection: DataProtectionRules,
}

impl ComplianceFramework {
    pub fn validate_compliance(&self, audit_trail: &AuditChain) -> ComplianceReport;
    pub fn generate_compliance_report(&self, period: TimePeriod) -> Report;
}

pub struct TOFUKeyStore {
    pinned_keys: HashMap<ProviderId, PinnedKey>,
    trust_policies: Vec<TrustPolicy>,
}

impl TOFUKeyStore {
    pub async fn pin_key(&mut self, provider: ProviderId, key: PublicKey) -> Result<()> {
        if self.pinned_keys.contains_key(&provider) {
            return Err("Key already pinned for provider");
        }

        self.pinned_keys.insert(provider, PinnedKey {
            public_key: key,
            pinned_at: SystemTime::now(),
            trust_level: TrustLevel::Unverified,
        });

        Ok(())
    }

    pub fn verify_tool(&self, tool: &MCPTool) -> VerificationResult {
        if let Some(pinned_key) = self.pinned_keys.get(&tool.provider_id) {
            if pinned_key.public_key.verify(&tool.schema_hash, &tool.signature) {
                VerificationResult::Trusted
            } else {
                VerificationResult::SignatureInvalid
            }
        } else {
            VerificationResult::UnknownProvider
        }
    }
}

pub struct SecurityAnalyzer {
    vulnerability_patterns: VulnerabilityDatabase,
    ml_detector: MaliciousCodeDetector,
    resource_analyzer: ResourceAnalyzer,
    privacy_assessor: PrivacyAssessor,
}

impl SecurityAnalyzer {
    pub async fn analyze_tool(&self, tool: &MCPTool) -> SecurityAnalysis {
        let mut findings = Vec::new();

        // Vulnerability pattern matching
        findings.extend(self.vulnerability_patterns.scan(&tool.schema));

        // ML-based detection
        let ml_result = self.ml_detector.analyze(&tool.schema).await?;
        findings.extend(ml_result.findings);

        // Resource usage analysis
        let resource_risk = self.resource_analyzer.assess(&tool.schema);

        // Privacy impact assessment
        let privacy_impact = self.privacy_assessor.evaluate(&tool.schema);

        SecurityAnalysis {
            tool_id: tool.id.clone(),
            risk_score: calculate_risk_score(&findings),
            findings,
            resource_requirements: resource_risk,
            privacy_impact,
            recommendation: self.generate_recommendation(&findings),
        }
    }
}

// Only allow these executables — everything else is blocked
ScanRule::AllowedExecutablesOnly(vec![
    "python3".into(),
    "node".into(),
    "cargo".into(),
])

let mut scanner = SkillScanner::new();
scanner.add_custom_rule(
    "block-internal-api",
    r"internal\.corp\.example\.com",
    ScanSeverity::High,
    "References to internal API endpoints are not allowed in skills",
);

pub struct SecureChannel {
    encryption_key: [u8; 32],
    mac_key: [u8; 32],
    send_counter: AtomicU64,
    recv_counter: AtomicU64,
}

impl SecureChannel {
    pub fn encrypt_message(&self, plaintext: &[u8]) -> Result<Vec<u8>> {
        let counter = self.send_counter.fetch_add(1, Ordering::SeqCst);
        let nonce = self.generate_nonce(counter);

        let ciphertext = ChaCha20Poly1305::new(&self.encryption_key)
            .encrypt(&nonce, plaintext)?;

        let mac = Hmac::<Sha256>::new_from_slice(&self.mac_key)?
            .chain_update(&ciphertext)
            .chain_update(&counter.to_le_bytes())
            .finalize()
            .into_bytes();

        Ok([ciphertext, mac.to_vec()].concat())
    }
}

pub enum ViolationSeverity {
    Info,       // Normal security events
    Warning,    // Minor policy violations
    Error,      // Confirmed security issues
    Critical,   // Active security breaches
}

pub struct SecurityEvent {
    pub id: Uuid,
    pub timestamp: SystemTime,
    pub severity: ViolationSeverity,
    pub category: SecurityEventCategory,
    pub description: String,
    pub affected_components: Vec<ComponentId>,
    pub recommended_actions: Vec<String>,
}