# Phase 9 Runtime Security Implementation Summary

## Overview

This document summarizes the Phase 9 Runtime Security features implemented for worker process isolation, network micro-segmentation, and hardened seccomp profiles.

## Phase 9.2: Worker Process Isolation

### Configuration Fields (internal/worker/config.go)

Added to `SandboxConfig`:
- `MaxProcesses` - Maximum number of processes (fork bomb protection)
- `MaxOpenFiles` - Maximum open file descriptors per task
- `DisableSwap` - Whether to disable swap via mlockall
- `OOMScoreAdj` - OOM killer priority adjustment
- `TaskUID` - Task user ID for privilege separation
- `TaskGID` - Task group ID for privilege separation

### Security Defaults (SecurityDefaults)

```go
MaxProcesses:  100  // Fork bomb protection
MaxOpenFiles:  1024 // FD limit
DisableSwap:   true // Swap disabled by default
OOMScoreAdj:   100  // Less likely to be killed
TaskUID:       1000 // Non-privileged UID
TaskGID:       1000 // Non-privileged GID
```

### Process Isolation Module (internal/worker/process/)

**isolation.go** - Core isolation logic:
- `ApplyIsolation()` - Applies all resource limits
- `IsolationConfig` struct for configuration
- `IsolatedExec()` - Helper for running commands with isolation
- `GetCurrentLimits()` - Diagnostic function

**isolation_unix.go** - Unix/Linux-specific:
- `applyResourceLimits()` - Sets RLIMIT_NPROC and RLIMIT_NOFILE
- `disableSwap()` - Uses mlockall(MCL_CURRENT|MCL_FUTURE)
- `setOOMScoreAdj()` - Writes to /proc/self/oom_score_adj

**isolation_windows.go** - Windows stubs:
- Graceful degradation with no-op implementations
- Platform-specific error messages

### Container Integration (internal/container/podman.go)

Updated `PodmanSecurityConfig` with process isolation fields.

Updated `BuildSecurityArgs()` to add:
- `--pids-limit` for fork bomb protection
- `--ulimit nofile` for FD limits
- `--oom-score-adj` for OOM priority
- `--memory-swap=0` to disable swap

### Container Executor (internal/worker/executor/container.go)

Updated `SandboxConfig` interface with process isolation getters.
Updated security config conversion to pass process isolation fields.

## Phase 9.3: Network Micro-Segmentation

### Network Policy Module (internal/worker/process/)

**network_policy.go** (Linux):
- `NetworkPolicy` struct for network rules
- `DefaultNetworkPolicy()` - Blocks all by default
- `HIPAACompliantPolicy()` - Restricted allowlist mode
- `ApplyNetworkPolicy()` - Adds podman network arguments
- `SetupExternalFirewall()` - iptables/nsenter integration

**network_policy_windows.go** (Windows):
- Windows stub implementations
- Validates network mode restrictions

## Phase 9.6: Seccomp Hardened Profile

### Seccomp Profile (configs/seccomp/default-hardened.json)

Already exists with hardened default syscalls.

### Integration (internal/container/podman.go)

`BuildSecurityArgs()` already applies seccomp profiles:
```go
if sandbox.SeccompProfile != "" && sandbox.SeccompProfile != "unconfined" {
    profilePath := GetSeccompProfilePath(sandbox.SeccompProfile)
    if profilePath != "" {
        args = append(args, "--security-opt", fmt.Sprintf("seccomp=%s", profilePath))
    }
}
```

## Files Modified

### Phase 9.2 Process Isolation
1. `internal/worker/config.go` - Added config fields and getter methods
2. `internal/worker/process/isolation.go` - Core isolation logic
3. `internal/worker/process/isolation_unix.go` - Unix-specific syscalls
4. `internal/worker/process/isolation_windows.go` - Windows stubs
5. `internal/container/podman.go` - PodmanSecurityConfig and BuildSecurityArgs
6. `internal/worker/executor/container.go` - SandboxConfig interface and integration

### Phase 9.3 Network Segmentation
7. `internal/worker/process/network_policy.go` - Linux network policy
8. `internal/worker/process/network_policy_windows.go` - Windows stub

### Phase 9.6 Seccomp
- Used existing `configs/seccomp/default-hardened.json`
- Already integrated via existing `GetSeccompProfilePath()`

## Testing

Build verification:
```bash
make dev  # Successful
```

All Go packages compile on:
- macOS (Darwin)
- Linux
- Windows

## Security Impact

| Feature | Threat Mitigated | Default Value |
|---------|------------------|---------------|
| MaxProcesses | Fork bombs | 100 processes |
| MaxOpenFiles | FD exhaustion | 1024 FDs |
| DisableSwap | Memory swapping | Enabled |
| OOMScoreAdj | Priority inversion | 100 (less likely killed) |
| NetworkMode | Data exfiltration | "none" |
| Seccomp | Kernel attack surface | Hardened profile |

## HIPAA Compliance

All Phase 9 features support HIPAA compliance mode:
- Network mode "none" enforced
- Seccomp profile required
- Process isolation enforced by default
- Resource limits prevent DoS
