Prism Proxy Security Requirements and Assessment Plan

Executive Summary

This memo defines the security requirements and assessment framework for the Prism Proxy (Rust), the high-performance data access gateway that routes client requests to backend drivers. As the proxy is the primary entry point for all client traffic, it requires comprehensive security controls.

Status: The proxy is planned but not yet implemented. This document serves as security requirements for the implementation phase.

Architecture Context

+-------------------+      +----------------+      +------------------+
|  Client Apps      | ---->| Prism Proxy    | ---->| Backend Drivers  |
|  (gRPC clients)   |      | (Rust/tonic)   |      | (Go plugins)     |
+-------------------+      +----------------+      +------------------+
        |                         |                         |
        v                         v                         v
    mTLS Auth               Rate Limiting             Redis, NATS
    JWT validation          Connection Pool           PostgreSQL, etc.

Security Requirements

1. Authentication (Required)

Requirement	Priority	OWASP	Description
mTLS support	P0	A01	Client certificate authentication for service-to-service
JWT validation	P0	A01	Bearer token validation with JWKS
API key auth	P1	A01	Fallback authentication mechanism
Token refresh	P1	A01	Support for token refresh flow
Auth bypass prevention	P0	A01	No unauthenticated access to data endpoints

Implementation Guidance:

// Suggested authentication interceptor pattern
pub struct AuthInterceptor {
    jwks_cache: JWKSCache,
    mtls_verifier: MtlsVerifier,
}

impl Interceptor for AuthInterceptor {
    fn call(&mut self, request: Request<()>) -> Result<Request<()>, Status> {
        // 1. Check mTLS certificate if present
        // 2. Validate JWT Bearer token
        // 3. Extract claims and attach to request context
        // 4. Return Unauthenticated on failure
    }
}

2. Authorization (Required)

Requirement	Priority	OWASP	Description
Namespace isolation	P0	A01	Clients can only access their namespaces
Role-based access	P0	A01	Admin vs operator vs reader roles
Per-operation authz	P1	A01	Read vs write permissions
Audit logging	P0	A09	Log all access decisions

Implementation Guidance:

// Namespace-scoped authorization check
async fn authorize_request(
    claims: &UserClaims,
    namespace: &str,
    operation: Operation,
) -> Result<(), Status> {
    // 1. Verify namespace ownership or delegation
    // 2. Check role permissions for operation
    // 3. Log access decision
}

3. Input Validation (Required)

Input	Validation	Max Size	Pattern
Namespace	DNS-safe	63 chars	^[a-z][a-z0-9-]*[a-z0-9]$
Key	UTF-8, no null bytes	1KB	Configurable
Value	Binary safe	10MB	Configurable
TTL	Positive integer	N/A	0-31536000 (1 year)
Metadata	JSON	64KB	Valid JSON

Implementation Guidance:

// Request validation at ingress
fn validate_request(req: &DataRequest) -> Result<(), ValidationError> {
    validate_namespace(&req.namespace)?;
    validate_key(&req.key, max_key_size)?;
    validate_value(&req.value, max_value_size)?;
    validate_ttl(req.ttl)?;
    Ok(())
}

4. Transport Security (Required)

Requirement	Priority	Description
TLS 1.3 minimum	P0	No TLS 1.2 or below
Strong cipher suites	P0	AEAD ciphers only
Certificate rotation	P1	Support hot reload
ALPN negotiation	P1	h2 protocol negotiation

Implementation Guidance:

// TLS configuration for tonic
let tls_config = ServerTlsConfig::new()
    .identity(identity)
    .client_ca_root(client_ca)  // For mTLS
    .with_protocol_versions(&[ProtocolVersion::TLSv1_3])
    .with_ciphersuites(&[
        CipherSuite::TLS13_AES_256_GCM_SHA384,
        CipherSuite::TLS13_CHACHA20_POLY1305_SHA256,
    ]);

5. Rate Limiting (Required)

Limit Type	Default	Scope	Description
Requests/second	1000	Per client	Overall request rate
Connections	100	Per client IP	Max concurrent connections
Bandwidth	100 MB/s	Per namespace	Data transfer rate
Payload size	10 MB	Per request	Max request body

Implementation Guidance:

// Token bucket rate limiter
pub struct RateLimiter {
    buckets: DashMap<ClientId, TokenBucket>,
    config: RateLimitConfig,
}

impl RateLimiter {
    pub fn check(&self, client: &ClientId) -> Result<(), RateLimitExceeded> {
        // 1. Get or create bucket for client
        // 2. Try to consume token
        // 3. Return remaining quota in headers
    }
}

6. Observability (Required)

Metric	Type	Labels	Description
proxy_requests_total	Counter	method, status, namespace	Request count
proxy_request_duration_seconds	Histogram	method, namespace	Latency
proxy_auth_failures_total	Counter	reason	Auth failure count
proxy_active_connections	Gauge		Current connections

Implementation Guidance:

// Prometheus metrics
lazy_static! {
    static ref REQUEST_COUNTER: IntCounterVec = register_int_counter_vec!(
        "proxy_requests_total",
        "Total requests processed",
        &["method", "status", "namespace"]
    ).unwrap();
}

7. Error Handling (Required)

Requirement	Description
No stack traces	Never expose internal errors to clients
Generic error messages	"Invalid request" not "SQL error at line..."
Error codes	Consistent error codes for client handling
Logging	Full details in server logs only

Implementation Guidance:

// Safe error mapping
fn map_error(err: InternalError) -> Status {
    // Log full error internally
    tracing::error!(?err, "Internal error");

    // Return safe error to client
    match err {
        InternalError::NotFound => Status::not_found("Resource not found"),
        InternalError::Unauthorized => Status::unauthenticated("Authentication required"),
        _ => Status::internal("Internal server error"),
    }
}

8. Memory Safety (Rust-specific)

Requirement	Description
No unsafe code	Avoid unsafe blocks unless absolutely necessary
Bounded allocations	Use bounded channels and pools
Timeout all operations	Prevent resource exhaustion
Graceful degradation	Shed load under pressure

Security Test Plan

Unit Tests

Category	Test Cases	Coverage Target
Auth	Token validation, mTLS verification	90%
Input validation	Boundary values, injection attempts	95%
Rate limiting	Token bucket behavior, overflow	85%
Error handling	Safe error mapping	90%

Integration Tests

Test	Description
E2E auth flow	Full authentication cycle
Namespace isolation	Cross-tenant access prevention
TLS negotiation	Certificate verification
Backend failover	Error handling on backend failure

Security Tests (Penetration)

Test	OWASP	Description
Auth bypass	A01	Attempt unauthenticated access
JWT manipulation	A01	Algorithm confusion, expired tokens
Input fuzzing	A03	Malformed requests, oversized payloads
DoS resilience	A07	Connection exhaustion, slowloris
TLS downgrade	A02	Protocol version negotiation

Compliance Checklist

Before Implementation

• Security requirements reviewed and approved
• Threat model documented
• Test plan approved

During Implementation

• No unsafe code without review
• All inputs validated at ingress
• All errors mapped to safe responses
• Metrics instrumented

Before Release

• Security test suite passing
• Penetration test completed
• Dependency audit clean
• Security documentation updated

Dependencies and Libraries

Recommended Crates

Purpose	Crate	Notes
gRPC	tonic	With TLS support
JWT	jsonwebtoken	Verify only, no signing
TLS	rustls	Memory-safe TLS
Rate limiting	governor	Token bucket implementation
Metrics	prometheus	Standard metrics format
Logging	tracing	Structured logging

Crates to Avoid

Crate	Reason
openssl	Memory safety concerns
Unmaintained crates	Security patches delayed

Conclusion

This document defines the security requirements for the Prism Proxy implementation. The proxy is a critical security boundary and must implement defense-in-depth with multiple layers of protection.

Key priorities:

1. Authentication at the transport layer (mTLS) AND application layer (JWT)
2. Strict input validation before any processing
3. Namespace-based authorization for multi-tenancy
4. Comprehensive observability for security monitoring

This document should be updated as the implementation progresses and specific design decisions are made.