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devopscritical PriorityID: cilium-ebpf-kernel-native-mtls-handshake-invariant

Cilium eBPF Kernel-Native mTLS and Cryptographic Identity Enforcement

Enforces kernel-native mTLS session authentication and cryptographic identity validation via Cilium eBPF without userspace sidecar proxies. Eliminates Envoy sidecar serialization, dual-network-stack hops, and context-switching overhead while guaranteeing non-bypassable zero-trust identity verification via SPIFFE/SPIRE and kernel-level WireGuard/IPsec payload encryption.

Prohibited Anti-Pattern: Bypassing Kernel mTLS Handshakes via Permissive Plaintext Fallback or Deploying Latency-Degrading Userspace Proxy Sidecars

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---
description: Cilium eBPF Kernel-Native mTLS and Cryptographic Identity Enforcement - Enforces kernel-native mTLS session authentication and cryptographic identity validation via Cilium eBPF without userspace sidecar proxies. Eliminates Envoy sidecar serialization, dual-network-stack hops, and context-switching overhead while guaranteeing non-bypassable zero-trust identity verification via SPIFFE/SPIRE and kernel-level WireGuard/IPsec payload encryption.
globs: **/cilium-*.yaml, **/values*.yaml, **/templates/**/*.yaml, k8s/**/*.yaml, policies/**/*.yaml
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/cilium-ebpf-kernel-native-mtls-handshake-invariant"
---

# Cilium eBPF Kernel-Native mTLS and Cryptographic Identity Enforcement

> **Severity**: CRITICAL | **Category**: devops
> **Anti-Pattern Warning**: Bypassing Kernel mTLS Handshakes via Permissive Plaintext Fallback or Deploying Latency-Degrading Userspace Proxy Sidecars

## System Constraints
You are a Principal Software Architect enforcing the Cilium eBPF Kernel-Native mTLS Handshake Invariant. You must reject any configurations introducing userspace sidecar proxy injection for transport encryption or permitting unauthenticated socket bypass in Cilium network policies. Mandate explicit SPIFFE-based kernel authentication handshakes and WireGuard encryption datapaths across all service mesh architectures.

## Strict Guidelines
- Engineers MUST ALWAYS configure `authentication.mode: required` in `CiliumNetworkPolicy` ingress and egress rules to mandate cryptographic mutual authentication.
- Engineers MUST NOT allow non-authenticated TCP traffic to bypass kernel verification via fallback routes or permissive default policies when identity handshakes fail.
- Code SHOULD enforce kernel-level WireGuard or IPsec datapath encryption (`encryption.type: wireguard`) at the cluster level in conjunction with SPIFFE identity attestation.
- Services MUST declare and validate exact SPIFFE IDs anchored to Kubernetes ServiceAccounts, preventing broad identity matching wildcards.
- Components NEVER inject userspace sidecar proxies (e.g., Istio Envoy, Linkerd) for transport encryption when kernel-level eBPF socket layer redirection (`sockops`) is operational.

## Bad vs Good Implementations
### CiliumNetworkPolicy mTLS Authentication Specification

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: Omitting the authentication stanza relies solely on mutable IP/label matching without cryptographic handshake validation, creating sidecar proxy latency overhead and exposing endpoints to label-spoofing and socket-level MITM attacks.
```yaml
# Anti-Pattern: Relies on userspace Envoy sidecars and unauthenticated L4 ingress
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
  name: secure-payment-service
  namespace: production
spec:
  endpointSelector:
    matchLabels:
      app: payment-service
  ingress:
    - fromEndpoints:
        - matchLabels:
            app: checkout-frontend
      toPorts:
        - ports:
            - port: "8443"
              protocol: TCP
          # Flaw: No authentication block. Packets traverse kernel sockets without
          # cryptographic identity attestation; relies on vulnerable userspace proxy sidecar.
```

#### Production Standard (Correct)
> **Standard**: The `authentication.mode: required` invariant instructs Cilium eBPF to halt packet forwarding until the Cilium agent completes an out-of-band SPIFFE/SPIRE mutual authentication handshake, caching the verified identity in eBPF maps for zero-sidecar kernel wire-speed transmission.
```yaml
# Production Invariant: Kernel-native SPIFFE-backed mTLS via Cilium eBPF
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
  name: secure-payment-service
  namespace: production
spec:
  endpointSelector:
    matchLabels:
      app: payment-service
  ingress:
    - fromEndpoints:
        - matchLabels:
            app: checkout-frontend
      authentication:
        mode: required
      toPorts:
        - ports:
            - port: "8443"
              protocol: TCP
```
Recommended MCP Servers (mcp-serverlist.com)

Equip agent with system tools to verify code for this stack.

Cilium Policy Inspector MCP
Analyzes CiliumNetworkPolicy manifests and live eBPF map states to verify zero-trust mutual authentication constraints.
Kubernetes Cluster MCP
Inspects running pod specs, Cilium node agent statuses, and SPIRE agent identity sockets inside Kubernetes.
Recommended Agent Skills (askills.dev)

Ready-to-use executable skill functions tailored to this stack.

Cilium CLI
Command-line tool for deploying, inspecting, and troubleshooting Cilium eBPF datapaths, policy enforcement, and mTLS status.
SPIRE CLI
CLI utility to inspect, mint, and validate SPIFFE IDs and SVID credentials issued to Kubernetes workloads.
Architectural Specification & Invariant Rationale

Architectural Invariant Design: Cilium eBPF Kernel-Native mTLS and Cryptographic Identity Enforcement

Cilium eBPF Kernel-Native mTLS and Cryptographic Identity Enforcement defines an industrial-grade behavioral standard for devops engineering. Enforces kernel-native mTLS session authentication and cryptographic identity validation via Cilium eBPF without userspace sidecar proxies. Eliminates Envoy sidecar serialization, dual-network-stack hops, and context-switching overhead while guaranteeing non-bypassable zero-trust identity verification via SPIFFE/SPIRE and kernel-level WireGuard/IPsec payload encryption. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Bypassing Kernel mTLS Handshakes via Permissive Plaintext Fallback or Deploying Latency-Degrading Userspace Proxy Sidecars Without an explicit system instruction file, developers spend hours debugging silent failures.
Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure ModeAI Symptom (The Anti-Pattern)SeverityProduction Impact & Remedy
AI Hallucination & Deprecation DriftBypassing Kernel mTLS Handshakes via Permissive Plaintext Fallback or Deploying Latency-Degrading Userspace Proxy SidecarsCritical
Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production.
Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture InconsistencyAI assistants produce mixed paradigms across files, creating fragmented codebase conventions.Medium
Increases cognitive load during code reviews and leads to maintenance debt across engineering teams.
Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.
Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

1

Engineers MUST ALWAYS configure `authentication.mode

Engineers MUST ALWAYS configure `authentication.mode: required` in `CiliumNetworkPolicy` ingress and egress rules to mandate cryptographic mutual authentication.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
2

Engineers MUST NOT allow non-authenticated TCP traffic to bypass kernel verification via fallback routes or permissive default policies when identity handshakes fail.

Engineers MUST NOT allow non-authenticated TCP traffic to bypass kernel verification via fallback routes or permissive default policies when identity handshakes fail.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
3

Code SHOULD enforce kernel-level WireGuard or IPsec datapath encryption (`encryption.type

Code SHOULD enforce kernel-level WireGuard or IPsec datapath encryption (`encryption.type: wireguard`) at the cluster level in conjunction with SPIFFE identity attestation.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
4

Services MUST declare and validate exact SPIFFE IDs anchored to Kubernetes ServiceAccounts, preventing broad identity matching wildcards.

Services MUST declare and validate exact SPIFFE IDs anchored to Kubernetes ServiceAccounts, preventing broad identity matching wildcards.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
5

Components NEVER inject userspace sidecar proxies (e.g., Istio Envoy, Linkerd) for transport encryption when kernel-level eBPF socket layer redirection (`sockops`) is operational.

Components NEVER inject userspace sidecar proxies (e.g., Istio Envoy, Linkerd) for transport encryption when kernel-level eBPF socket layer redirection (`sockops`) is operational.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
Technical Questions & Answers

Frequently Asked Technical Questions

Common questions developers face when configuring AI coding assistants for this stack:

Q:Why is Cilium eBPF Kernel-Native mTLS and Cryptographic Identity Enforcement critical for AI coding assistants?

Enforces kernel-native mTLS session authentication and cryptographic identity validation via Cilium eBPF without userspace sidecar proxies. Eliminates Envoy sidecar serialization, dual-network-stack hops, and context-switching overhead while guaranteeing non-bypassable zero-trust identity verification via SPIFFE/SPIRE and kernel-level WireGuard/IPsec payload encryption. Without explicit behavioral boundaries, AI coding assistants (Cursor, Claude Code, Windsurf, Codex) rely on training data averages, which frequently produce deprecated, inefficient, or vulnerable code patterns.

Q:How does adopting this rule prevent AI hallucinations?

This rule explicitly declares what the AI must avoid (Bypassing Kernel mTLS Handshakes via Permissive Plaintext Fallback or Deploying Latency-Degrading Userspace Proxy Sidecars) and prescribes verified positive examples. Grounding the LLM with negative and positive pairs eliminates guesswork.

Q:Which AI coding environments are supported?

This specification is multi-platform compatible: Cursor (.cursor/rules/*.mdc & .cursorrules), Anthropic Claude Code (CLAUDE.md), Windsurf (.windsurfrules), Codex / Cline (AGENTS.md), and GitHub Copilot (.github/copilot-instructions.md).

Q:Can I combine this rule with other technology stacks?

Yes. Use the Interactive Stack Builder or download an Agent Pack to merge this rule with other frontend, backend, database, security, and DevOps rules without syntax collision.

Open Specification · CC BY 4.0·Free for Personal, Team & Commercial In-Repo Use

Citation & Open Source Attribution Guidelines

This specification is licensed under Creative Commons Attribution 4.0 International (CC BY 4.0). You are completely free to adapt and share this rule in your workspace. If citing, including in public AI benchmark datasets, or redistributing, attribution to AgentRules.org is required.

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