gVisor Sandbox Integration in Java: Complete Guide

Introduction to gVisor Sandbox

gVisor is a user-space kernel that provides a secure sandbox for containers. It implements Linux system call interfaces in Go, providing isolation while maintaining compatibility. This guide covers integrating and managing gVisor with Java applications.

System Architecture Overview

gVisor Sandbox Architecture ├── Host Kernel │ ├ - KVM (optional) │ └ - Sentry (gVisor kernel) ├── Sandbox Isolation │ ├ - System Call Interception │ ├ - Virtualized Filesystem (VFS2) │ └ - Network Stack ├── Java Integration │ ├ - JNI Bindings │ ├ - Runtime Configuration │ └ - Performance Monitoring └── Security Features ├ - Seccomp Filters ├ - Capability Dropping └ - Namespace Isolation

Core Implementation

1. Maven Dependencies

<properties> <gvisor.version>0.0.0</gvisor.version> <jna.version>5.13.0</jna.version> <netty.version>4.1.100.Final</netty.version> </properties> <dependencies> <!-- JNI for gVisor integration --> <dependency> <groupId>net.java.dev.jna</groupId> <artifactId>jna</artifactId> <version>${jna.version}</version> </dependency> <dependency> <groupId>net.java.dev.jna</groupId> <artifactId>jna-platform</artifactId> <version>${jna.version}</version> </dependency> <!-- gVisor client library --> <dependency> <groupId>com.google.gvisor</groupId> <artifactId>gvisor-api</artifactId> <version>${gvisor.version}</version> </dependency> <!-- Container runtime interface --> <dependency> <groupId>io.containerd</groupId> <artifactId>containerd-client</artifactId> <version>1.7.8</version> </dependency> <!-- Process management --> <dependency> <groupId>org.zeroturnaround</groupId> <artifactId>zt-exec</artifactId> <version>1.12</version> </dependency> <!-- System monitoring --> <dependency> <groupId>com.github.oshi</groupId> <artifactId>oshi-core</artifactId> <version>6.4.6</version> </dependency> <!-- Network utilities --> <dependency> <groupId>io.netty</groupId> <artifactId>netty-all</artifactId> <version>${netty.version}</version> </dependency> </dependencies>

2. gVisor Runtime Manager

package com.gvisor.sandbox; import com.sun.jna.*; import com.sun.jna.ptr.*; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.stereotype.Service; import java.io.*; import java.nio.file.*; import java.util.*; import java.util.concurrent.*; @Service public class GVisorRuntimeManager { private static final Logger logger = LoggerFactory.getLogger(GVisorRuntimeManager.class); // gVisor paths and constants private static final String RUNSC_PATH = "/usr/local/bin/runsc"; private static final String GVISOR_CONFIG = "/etc/gvisor/gvisor.conf"; private static final String SOCKET_DIR = "/run/gvisor"; // Native gVisor library interface private GVisorNative gvisorNative; // Active sandboxes private final Map<String, SandboxInstance> sandboxes = new ConcurrentHashMap<>(); private final ExecutorService sandboxExecutor = Executors.newCachedThreadPool(); @PostConstruct public void initialize() throws IOException { // Load native library loadNativeLibrary(); // Verify gVisor installation verifyGVisorInstallation(); // Create runtime directories createRuntimeDirectories(); // Load configuration loadConfiguration(); logger.info("gVisor Runtime Manager initialized"); } /** * Create a new gVisor sandbox */ public SandboxInstance createSandbox(SandboxConfig config) throws GVisorException { String sandboxId = UUID.randomUUID().toString(); try { SandboxInstance sandbox = new SandboxInstance(sandboxId, config); // Create sandbox directory structure createSandboxFilesystem(sandbox); // Configure network namespace configureNetworkNamespace(sandbox); // Start the sandbox startSandboxProcess(sandbox); // Monitor sandbox health startHealthMonitoring(sandbox); sandboxes.put(sandboxId, sandbox); logger.info("Created sandbox: {}", sandboxId); return sandbox; } catch (Exception e) { throw new GVisorException("Failed to create sandbox", e); } } /** * Execute a Java process inside sandbox */ public ProcessExecution executeInSandbox(String sandboxId, String[] command, Map<String, String> env) throws GVisorException { SandboxInstance sandbox = sandboxes.get(sandboxId); if (sandbox == null) { throw new GVisorException("Sandbox not found: " + sandboxId); } try { // Prepare execution context ExecutionContext context = new ExecutionContext(command, env); // Create process inside sandbox long pid = createProcessInSandbox(sandbox, context); // Monitor process execution ProcessExecution execution = new ProcessExecution(pid, sandboxId); monitorProcessExecution(execution); return execution; } catch (Exception e) { throw new GVisorException("Failed to execute in sandbox", e); } } /** * Run Java application in isolated sandbox */ public JavaSandboxResult runJavaApplication(String jarPath, String mainClass, String[] args, ResourceLimits limits) throws GVisorException { SandboxConfig config = SandboxConfig.builder() .withIsolationLevel(IsolationLevel.STRICT) .withResourceLimits(limits) .withJavaRuntime(true) .build(); SandboxInstance sandbox = createSandbox(config); try { // Copy JAR into sandbox copyJarToSandbox(sandbox, jarPath); // Prepare Java command String[] command = buildJavaCommand(mainClass, args, limits); // Execute ProcessExecution execution = executeInSandbox( sandbox.getId(), command, getJavaEnvironment() ); // Wait for completion execution.waitFor(); // Collect results return collectJavaResults(sandbox, execution); } finally { // Cleanup destroySandbox(sandbox.getId()); } } /** * Configure sandbox with security policies */ private void configureSecurityPolicies(SandboxInstance sandbox) throws IOException { // Apply seccomp filters applySeccompFilters(sandbox); // Drop capabilities dropCapabilities(sandbox); // Configure namespaces configureNamespaces(sandbox); // Set resource limits applyResourceLimits(sandbox); logger.debug("Security policies applied for sandbox: {}", sandbox.getId()); } /** * Apply seccomp filters to restrict system calls */ private void applySeccompFilters(SandboxInstance sandbox) throws IOException { Path seccompProfile = Paths.get(sandbox.getRootPath(), "seccomp.json"); String seccompConfig = """ { "defaultAction": "SCMP_ACT_ERRNO", "architectures": [ "SCMP_ARCH_X86_64", "SCMP_ARCH_X86", "SCMP_ARCH_X32" ], "syscalls": [ { "names": [ "accept", "accept4", "access", "arch_prctl", "bind", "brk", "clock_gettime", "clone", "close", "connect", "dup", "dup2", "epoll_ctl", "epoll_wait", "execve", "exit", "exit_group", "fcntl", "fstat", "futex", "getcwd", "getdents64", "getpid", "getppid", "getrandom", "getsockname", "getsockopt", "ioctl", "listen", "lseek", "mmap", "mprotect", "munmap", "nanosleep", "newfstatat", "openat", "pipe", "poll", "pread64", "prlimit64", "pwrite64", "read", "readlink", "recvfrom", "recvmsg", "rt_sigaction", "rt_sigprocmask", "rt_sigreturn", "sendmsg", "sendto", "setsockopt", "socket", "write", "writev" ], "action": "SCMP_ACT_ALLOW" } ] } """; Files.writeString(seccompProfile, seccompConfig); // Apply via runsc String[] cmd = { RUNSC_PATH, "--root", sandbox.getRootPath(), "seccomp", "install", seccompProfile.toString() }; executeCommand(cmd); } /** * Configure network namespace for sandbox */ private void configureNetworkNamespace(SandboxInstance sandbox) throws IOException { // Create network namespace String[] createNs = { "ip", "netns", "add", "gvisor-" + sandbox.getId() }; executeCommand(createNs); // Configure veth pair configureVethPair(sandbox); // Set up iptables rules configureIptables(sandbox); logger.debug("Network namespace configured for sandbox: {}", sandbox.getId()); } /** * Monitor sandbox performance */ public SandboxMetrics getSandboxMetrics(String sandboxId) throws GVisorException { SandboxInstance sandbox = sandboxes.get(sandboxId); if (sandbox == null) { throw new GVisorException("Sandbox not found: " + sandboxId); } SandboxMetrics metrics = new SandboxMetrics(); try { // Get CPU usage metrics.setCpuUsage(getCpuUsage(sandbox)); // Get memory usage metrics.setMemoryUsage(getMemoryUsage(sandbox)); // Get network statistics metrics.setNetworkStats(getNetworkStats(sandbox)); // Get filesystem statistics metrics.setFilesystemStats(getFilesystemStats(sandbox)); // Get process count metrics.setProcessCount(getProcessCount(sandbox)); } catch (Exception e) { throw new GVisorException("Failed to get sandbox metrics", e); } return metrics; } /** * Attach debugger to sandbox */ public DebugSession attachDebugger(String sandboxId, DebugConfig config) throws GVisorException { SandboxInstance sandbox = sandboxes.get(sandboxId); if (sandbox == null) { throw new GVisorException("Sandbox not found: " + sandboxId); } try { // Create debug session DebugSession session = new DebugSession(sandboxId, config); // Attach to sandbox attachToSandbox(sandbox, session); // Start debug server startDebugServer(session); return session; } catch (Exception e) { throw new GVisorException("Failed to attach debugger", e); } } /** * Take snapshot of sandbox state */ public SandboxSnapshot takeSnapshot(String sandboxId, String snapshotPath) throws GVisorException { SandboxInstance sandbox = sandboxes.get(sandboxId); if (sandbox == null) { throw new GVisorException("Sandbox not found: " + sandboxId); } try { // Pause sandbox for consistent snapshot pauseSandbox(sandbox); // Take filesystem snapshot Path snapshotDir = Paths.get(snapshotPath); takeFilesystemSnapshot(sandbox, snapshotDir); // Save memory state saveMemoryState(sandbox, snapshotDir); // Save process state saveProcessState(sandbox, snapshotDir); // Resume sandbox resumeSandbox(sandbox); return new SandboxSnapshot(sandboxId, snapshotDir); } catch (Exception e) { throw new GVisorException("Failed to take snapshot", e); } } /** * Restore sandbox from snapshot */ public SandboxInstance restoreFromSnapshot(SandboxSnapshot snapshot) throws GVisorException { try { // Create new sandbox configuration from snapshot SandboxConfig config = readConfigFromSnapshot(snapshot); // Create sandbox SandboxInstance sandbox = new SandboxInstance( UUID.randomUUID().toString(), config ); // Restore filesystem restoreFilesystem(sandbox, snapshot); // Restore memory state restoreMemoryState(sandbox, snapshot); // Start restored sandbox startSandboxProcess(sandbox); sandboxes.put(sandbox.getId(), sandbox); logger.info("Restored sandbox from snapshot: {}", sandbox.getId()); return sandbox; } catch (Exception e) { throw new GVisorException("Failed to restore from snapshot", e); } } /** * Destroy sandbox and cleanup resources */ public void destroySandbox(String sandboxId) throws GVisorException { SandboxInstance sandbox = sandboxes.remove(sandboxId); if (sandbox == null) { throw new GVisorException("Sandbox not found: " + sandboxId); } try { // Stop sandbox process stopSandboxProcess(sandbox); // Cleanup network namespace cleanupNetworkNamespace(sandbox); // Remove sandbox directory cleanupSandboxFilesystem(sandbox); logger.info("Destroyed sandbox: {}", sandboxId); } catch (Exception e) { throw new GVisorException("Failed to destroy sandbox", e); } } // Helper methods private void loadNativeLibrary() { try { gvisorNative = Native.load("gvisor", GVisorNative.class); logger.debug("Loaded gVisor native library"); } catch (UnsatisfiedLinkError e) { logger.warn("gVisor native library not found, using command-line interface"); gvisorNative = null; } } private void verifyGVisorInstallation() throws IOException { if (!Files.exists(Paths.get(RUNSC_PATH))) { throw new IOException("runsc not found at: " + RUNSC_PATH); } // Test runsc String[] testCmd = {RUNSC_PATH, "--version"}; Process process = new ProcessBuilder(testCmd).start(); try (BufferedReader reader = new BufferedReader( new InputStreamReader(process.getInputStream()))) { String version = reader.readLine(); logger.info("gVisor version: {}", version); } } private void createRuntimeDirectories() throws IOException { Files.createDirectories(Paths.get(SOCKET_DIR)); Files.createDirectories(Paths.get("/var/run/gvisor")); // Set appropriate permissions Files.setPosixFilePermissions(Paths.get(SOCKET_DIR), EnumSet.of( PosixFilePermission.OWNER_READ, PosixFilePermission.OWNER_WRITE, PosixFilePermission.OWNER_EXECUTE, PosixFilePermission.GROUP_READ, PosixFilePermission.GROUP_EXECUTE ) ); } private void loadConfiguration() throws IOException { if (Files.exists(Paths.get(GVISOR_CONFIG))) { Properties props = new Properties(); try (InputStream is = Files.newInputStream(Paths.get(GVISOR_CONFIG))) { props.load(is); } // Load configuration } } private void executeCommand(String[] command) throws IOException { ProcessBuilder pb = new ProcessBuilder(command); pb.redirectErrorStream(true); Process process = pb.start(); try { int exitCode = process.waitFor(); if (exitCode != 0) { String output = new String(process.getInputStream().readAllBytes()); throw new IOException("Command failed: " + String.join(" ", command) + "\nOutput: " + output); } } catch (InterruptedException e) { Thread.currentThread().interrupt(); throw new IOException("Command interrupted", e); } } // Native interface definition public interface GVisorNative extends Library { // Native methods for gVisor interaction long create_sandbox(String config_json, int config_len); int destroy_sandbox(long sandbox_id); long create_process(long sandbox_id, String[] argv, int argc, String[] envp, int envc); int wait_process(long process_id, IntByReference exit_code); int get_sandbox_metrics(long sandbox_id, ByteBuffer metrics_buffer, int buffer_size); } // Data classes public static class SandboxConfig { private IsolationLevel isolationLevel; private ResourceLimits resourceLimits; private boolean enableNetworking; private boolean enableJavaRuntime; private List<String> mountedVolumes; private Map<String, String> environment; // Builder pattern public static Builder builder() { return new Builder(); } public static class Builder { private final SandboxConfig config = new SandboxConfig(); public Builder withIsolationLevel(IsolationLevel level) { config.isolationLevel = level; return this; } public Builder withResourceLimits(ResourceLimits limits) { config.resourceLimits = limits; return this; } public Builder withJavaRuntime(boolean enable) { config.enableJavaRuntime = enable; return this; } public SandboxConfig build() { return config; } } // getters } public static class SandboxInstance { private final String id; private final SandboxConfig config; private final String rootPath; private Process process; private long nativeHandle; private volatile boolean running; public SandboxInstance(String id, SandboxConfig config) { this.id = id; this.config = config; this.rootPath = "/var/run/gvisor/" + id; } // getters and setters } public enum IsolationLevel { PERMISSIVE, // Minimal restrictions MODERATE, // Balanced security/performance STRICT, // Maximum security PARANOID // Extreme restrictions } public static class ResourceLimits { private long memoryLimit; // bytes private int cpuShares; // relative CPU weight private int cpuQuota; // microseconds per period private int cpuPeriod; // microseconds private int processLimit; // max processes private int fileDescriptorLimit; // getters and setters } public static class GVisorException extends Exception { public GVisorException(String message) { super(message); } public GVisorException(String message, Throwable cause) { super(message, cause); } } }

3. Java Sandbox Runner

package com.gvisor.sandbox; import java.io.*; import java.nio.file.*; import java.util.*; public class JavaSandboxRunner { private final GVisorRuntimeManager runtimeManager; private final SecurityPolicyManager policyManager; public JavaSandboxRunner() { this.runtimeManager = new GVisorRuntimeManager(); this.policyManager = new SecurityPolicyManager(); } /** * Run untrusted Java code in sandbox */ public ExecutionResult runUntrustedCode(String javaCode, List<String> dependencies, ExecutionConstraints constraints) throws SandboxException { try { // Create temporary directory for code Path tempDir = createTempWorkspace(); // Write Java code Path sourceFile = writeJavaSource(tempDir, javaCode); // Download and install dependencies installDependencies(tempDir, dependencies); // Compile Java code compileJavaCode(tempDir, sourceFile); // Create sandbox configuration SandboxConfig config = createSandboxConfig(constraints); // Run in sandbox return executeInSandbox(tempDir, config, constraints); } catch (Exception e) { throw new SandboxException("Failed to run untrusted code", e); } } /** * Run Java application with security policy */ public ExecutionResult runWithSecurityPolicy(String jarPath, String mainClass, String[] args, SecurityPolicy policy) throws SandboxException { try { // Create sandbox configuration from policy SandboxConfig config = policyManager.createSandboxConfig(policy); // Set resource limits config.setResourceLimits(policy.getResourceLimits()); // Run application return runtimeManager.runJavaApplication( jarPath, mainClass, args, policy.getResourceLimits() ); } catch (GVisorException e) { throw new SandboxException("Sandbox execution failed", e); } } /** * Execute Java main method in isolated environment */ public Object executeMainMethod(Class<?> clazz, String methodName, Class<?>[] paramTypes, Object[] args, SecurityContext context) throws SandboxException { try { // Create sandbox for class execution SandboxConfig config = createClassExecutionConfig(clazz, context); // Serialize class and arguments byte[] classData = serializeClass(clazz); byte[] argumentData = serializeArguments(args); // Create isolated classloader IsolatedClassLoader classLoader = createIsolatedClassLoader( config, classData, context ); // Load and execute class return executeClassInIsolation(classLoader, clazz.getName(), methodName, paramTypes, args); } catch (Exception e) { throw new SandboxException("Failed to execute main method", e); } } /** * Benchmark sandbox performance */ public PerformanceBenchmark benchmarkSandbox(BenchmarkConfig config) throws SandboxException { PerformanceBenchmark benchmark = new PerformanceBenchmark(); try { // Warm up benchmark.setWarmupResults(warmupBenchmark(config)); // Run benchmarks for (BenchmarkTest test : config.getTests()) { BenchmarkResult result = runBenchmarkTest(test, config.getIterations()); benchmark.addResult(test.getName(), result); } // Calculate statistics benchmark.calculateStatistics(); return benchmark; } catch (Exception e) { throw new SandboxException("Benchmark failed", e); } } private Path createTempWorkspace() throws IOException { Path tempDir = Files.createTempDirectory("java-sandbox-"); // Set secure permissions Files.setPosixFilePermissions(tempDir, EnumSet.of( PosixFilePermission.OWNER_READ, PosixFilePermission.OWNER_WRITE, PosixFilePermission.OWNER_EXECUTE ) ); return tempDir; } private Path writeJavaSource(Path dir, String javaCode) throws IOException { // Extract class name from code (simplified) String className = extractClassName(javaCode); Path sourceFile = dir.resolve(className + ".java"); Files.writeString(sourceFile, javaCode); return sourceFile; } private void installDependencies(Path dir, List<String> dependencies) throws IOException { Path libDir = dir.resolve("lib"); Files.createDirectories(libDir); for (String dependency : dependencies) { // Download dependency (simplified) downloadDependency(dependency, libDir); } } private void compileJavaCode(Path dir, Path sourceFile) throws IOException { String[] compileCommand = { "javac", "-cp", buildClassPath(dir), "-d", dir.toString(), sourceFile.toString() }; ProcessBuilder pb = new ProcessBuilder(compileCommand); Process process = pb.start(); try { int exitCode = process.waitFor(); if (exitCode != 0) { String error = new String(process.getErrorStream().readAllBytes()); throw new IOException("Compilation failed: " + error); } } catch (InterruptedException e) { Thread.currentThread().interrupt(); throw new IOException("Compilation interrupted", e); } } private String buildClassPath(Path dir) { Path libDir = dir.resolve("lib"); StringBuilder classPath = new StringBuilder(dir.toString()); try { if (Files.exists(libDir)) { try (DirectoryStream<Path> stream = Files.newDirectoryStream(libDir, "*.jar")) { for (Path jar : stream) { classPath.append(File.pathSeparator).append(jar.toString()); } } } } catch (IOException e) { // Ignore, use basic classpath } return classPath.toString(); } private SandboxConfig createSandboxConfig(ExecutionConstraints constraints) { return SandboxConfig.builder() .withIsolationLevel(IsolationLevel.STRICT) .withResourceLimits(constraints.getResourceLimits()) .withJavaRuntime(true) .build(); } private ExecutionResult executeInSandbox(Path workspace, SandboxConfig config, ExecutionConstraints constraints) throws GVisorException { // Find compiled class Path classFile = findClassFile(workspace); // Run in gVisor sandbox return runtimeManager.runJavaApplication( classFile.toString(), extractClassNameFromFile(classFile), new String[0], constraints.getResourceLimits() ); } // Data classes public static class ExecutionConstraints { private ResourceLimits resourceLimits; private SecurityLevel securityLevel; private NetworkAccess networkAccess; private List<String> allowedSystemCalls; private int timeoutSeconds; // getters and setters } public static class ExecutionResult { private int exitCode; private String stdout; private String stderr; private long executionTime; private ResourceUsage resourceUsage; private List<SecurityEvent> securityEvents; // getters and setters } public static class SecurityEvent { private EventType type; private String message; private long timestamp; private Severity severity; // getters and setters } public enum EventType { SYSTEM_CALL_VIOLATION, RESOURCE_LIMIT_EXCEEDED, NETWORK_ACCESS_DENIED, FILESYSTEM_ACCESS_DENIED } public enum Severity { INFO, WARNING, ERROR, CRITICAL } public static class SandboxException extends Exception { public SandboxException(String message) { super(message); } public SandboxException(String message, Throwable cause) { super(message, cause); } } }

4. Security Policy Manager

package com.gvisor.sandbox; import com.fasterxml.jackson.databind.ObjectMapper; import org.springframework.stereotype.Service; import java.io.*; import java.nio.file.*; import java.util.*; @Service public class SecurityPolicyManager { private final ObjectMapper objectMapper = new ObjectMapper(); private final Map<String, SecurityPolicy> policies = new HashMap<>(); /** * Load security policies from directory */ public void loadPolicies(Path policyDir) throws IOException { if (!Files.exists(policyDir)) { Files.createDirectories(policyDir); } try (DirectoryStream<Path> stream = Files.newDirectoryStream(policyDir, "*.json")) { for (Path policyFile : stream) { SecurityPolicy policy = objectMapper.readValue( policyFile.toFile(), SecurityPolicy.class ); policies.put(policy.getName(), policy); } } logger.info("Loaded {} security policies", policies.size()); } /** * Create sandbox configuration from policy */ public SandboxConfig createSandboxConfig(SecurityPolicy policy) { return SandboxConfig.builder() .withIsolationLevel(policy.getIsolationLevel()) .withResourceLimits(policy.getResourceLimits()) .withJavaRuntime(policy.isJavaRuntimeEnabled()) .build(); } /** * Apply policy to existing sandbox */ public void applyPolicyToSandbox(String sandboxId, SecurityPolicy policy) throws GVisorException { // Apply seccomp filters applySeccompPolicy(sandboxId, policy.getSeccompProfile()); // Apply capability restrictions applyCapabilityPolicy(sandboxId, policy.getCapabilities()); // Apply network policies applyNetworkPolicy(sandboxId, policy.getNetworkRules()); // Apply filesystem policies applyFilesystemPolicy(sandboxId, policy.getFilesystemRules()); logger.info("Applied policy '{}' to sandbox '{}'", policy.getName(), sandboxId); } /** * Validate Java code against policy */ public PolicyValidation validateJavaCode(String javaCode, SecurityPolicy policy) { PolicyValidation validation = new PolicyValidation(); // Check for disallowed APIs checkDisallowedApis(javaCode, policy, validation); // Check for resource usage patterns checkResourcePatterns(javaCode, policy, validation); // Check for security vulnerabilities checkSecurityVulnerabilities(javaCode, policy, validation); return validation; } /** * Create custom policy from template */ public SecurityPolicy createCustomPolicy(PolicyTemplate template, Map<String, Object> parameters) { SecurityPolicy policy = new SecurityPolicy(); policy.setName(template.getName() + "-custom"); // Configure based on template switch (template) { case UNTRUSTED_CODE: policy.setIsolationLevel(IsolationLevel.STRICT); policy.setResourceLimits(createStrictLimits()); policy.setNetworkAccess(NetworkAccess.NONE); break; case WEB_APPLICATION: policy.setIsolationLevel(IsolationLevel.MODERATE); policy.setResourceLimits(createWebAppLimits()); policy.setNetworkAccess(NetworkAccess.RESTRICTED); break; case BATCH_PROCESSING: policy.setIsolationLevel(IsolationLevel.PERMISSIVE); policy.setResourceLimits(createBatchLimits()); policy.setNetworkAccess(NetworkAccess.LOCAL_ONLY); break; } // Apply parameters applyParameters(policy, parameters); return policy; } private void applySeccompPolicy(String sandboxId, SeccompProfile profile) throws GVisorException { // Convert profile to JSON try { String profileJson = objectMapper.writeValueAsString(profile); // Apply to sandbox Path profilePath = Paths.get("/tmp/seccomp-" + sandboxId + ".json"); Files.writeString(profilePath, profileJson); // Use runsc to apply String[] cmd = { "runsc", "--root", getSandboxRoot(sandboxId), "seccomp", "install", profilePath.toString() }; Process process = new ProcessBuilder(cmd).start(); int exitCode = process.waitFor(); if (exitCode != 0) { throw new GVisorException("Failed to apply seccomp policy"); } } catch (IOException | InterruptedException e) { throw new GVisorException("Failed to apply seccomp policy", e); } } private ResourceLimits createStrictLimits() { ResourceLimits limits = new ResourceLimits(); limits.setMemoryLimit(256 * 1024 * 1024); // 256MB limits.setCpuShares(256); limits.setProcessLimit(50); limits.setFileDescriptorLimit(1024); return limits; } private void checkDisallowedApis(String javaCode, SecurityPolicy policy, PolicyValidation validation) { for (String disallowedApi : policy.getDisallowedApis()) { if (javaCode.contains(disallowedApi)) { validation.addViolation( PolicyViolation.DISALLOWED_API, "Use of disallowed API: " + disallowedApi ); } } } // Data classes public static class SecurityPolicy { private String name; private IsolationLevel isolationLevel; private ResourceLimits resourceLimits; private NetworkAccess networkAccess; private SeccompProfile seccompProfile; private List<String> capabilities; private List<String> disallowedApis; private List<NetworkRule> networkRules; private List<FilesystemRule> filesystemRules; private boolean javaRuntimeEnabled; // getters and setters } public static class SeccompProfile { private String defaultAction; private List<String> architectures; private List<SyscallRule> syscalls; // getters and setters } public static class SyscallRule { private List<String> names; private String action; private List<ArgRule> args; // getters and setters } public static class PolicyValidation { private boolean valid = true; private List<PolicyViolation> violations = new ArrayList<>(); public void addViolation(PolicyViolation type, String message) { violations.add(new PolicyViolation(type, message)); valid = false; } // getters } public enum PolicyViolation { DISALLOWED_API, RESOURCE_VIOLATION, SECURITY_RISK, POLICY_VIOLATION } public enum PolicyTemplate { UNTRUSTED_CODE, WEB_APPLICATION, BATCH_PROCESSING, DATA_PROCESSING, API_SERVER } }

5. Network Isolation Service

package com.gvisor.sandbox; import io.netty.bootstrap.Bootstrap; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.*; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.nio.NioServerSocketChannel; import io.netty.channel.socket.nio.NioSocketChannel; import org.springframework.stereotype.Service; import java.net.*; import java.util.*; import java.util.concurrent.*; @Service public class NetworkIsolationService { private final EventLoopGroup bossGroup = new NioEventLoopGroup(1); private final EventLoopGroup workerGroup = new NioEventLoopGroup(); private final Map<String, Channel> sandboxChannels = new ConcurrentHashMap<>(); /** * Create isolated network for sandbox */ public IsolatedNetwork createIsolatedNetwork(String sandboxId, NetworkConfig config) throws NetworkException { try { IsolatedNetwork network = new IsolatedNetwork(sandboxId); // Create virtual network interface createVirtualInterface(network, config); // Configure iptables rules configureIptables(network, config); // Set up network namespace setupNetworkNamespace(network); // Start proxy server startNetworkProxy(network, config); logger.info("Created isolated network for sandbox: {}", sandboxId); return network; } catch (Exception e) { throw new NetworkException("Failed to create isolated network", e); } } /** * Setup network proxy between host and sandbox */ private void startNetworkProxy(IsolatedNetwork network, NetworkConfig config) { ServerBootstrap bootstrap = new ServerBootstrap(); bootstrap.group(bossGroup, workerGroup) .channel(NioServerSocketChannel.class) .childHandler(new ChannelInitializer<io.netty.channel.socket.SocketChannel>() { @Override protected void initChannel(io.netty.channel.socket.SocketChannel ch) { // Create proxy pipeline ch.pipeline().addLast(new NetworkProxyHandler(network)); } }) .option(ChannelOption.SO_BACKLOG, 128) .childOption(ChannelOption.SO_KEEPALIVE, true); // Bind to host port ChannelFuture future = bootstrap.bind(config.getHostPort()).syncUninterruptibly(); sandboxChannels.put(network.getSandboxId(), future.channel()); logger.debug("Started network proxy for sandbox: {} on port {}", network.getSandboxId(), config.getHostPort()); } /** * Configure network policies */ public void configureNetworkPolicies(String sandboxId, List<NetworkPolicy> policies) throws NetworkException { try { for (NetworkPolicy policy : policies) { switch (policy.getType()) { case FIREWALL: configureFirewallPolicy(sandboxId, policy); break; case RATE_LIMITING: configureRateLimiting(sandboxId, policy); break; case CONTENT_FILTERING: configureContentFiltering(sandboxId, policy); break; case TLS_INSPECTION: configureTlsInspection(sandboxId, policy); break; } } } catch (Exception e) { throw new NetworkException("Failed to configure network policies", e); } } /** * Monitor network traffic */ public NetworkMetrics monitorNetworkTraffic(String sandboxId) throws NetworkException { NetworkMetrics metrics = new NetworkMetrics(); try { // Get network statistics from namespace String namespace = "gvisor-" + sandboxId; // RX/TX bytes metrics.setBytesReceived(getNetworkStat(namespace, "rx_bytes")); metrics.setBytesTransmitted(getNetworkStat(namespace, "tx_bytes")); // Packet counts metrics.setPacketsReceived(getNetworkStat(namespace, "rx_packets")); metrics.setPacketsTransmitted(getNetworkStat(namespace, "tx_packets")); // Error counts metrics.setErrorsReceived(getNetworkStat(namespace, "rx_errors")); metrics.setErrorsTransmitted(getNetworkStat(namespace, "tx_errors")); // Connection count metrics.setActiveConnections(getActiveConnections(sandboxId)); } catch (Exception e) { throw new NetworkException("Failed to monitor network traffic", e); } return metrics; } /** * Network proxy handler */ private static class NetworkProxyHandler extends ChannelInboundHandlerAdapter { private final IsolatedNetwork network; private Channel sandboxChannel; public NetworkProxyHandler(IsolatedNetwork network) { this.network = network; } @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { // Connect to sandbox Bootstrap bootstrap = new Bootstrap(); bootstrap.group(ctx.channel().eventLoop()) .channel(NioSocketChannel.class) .handler(new ChannelInitializer<io.netty.channel.socket.SocketChannel>() { @Override protected void initChannel(io.netty.channel.socket.SocketChannel ch) { ch.pipeline().addLast(new SandboxResponseHandler(ctx.channel())); } }); ChannelFuture future = bootstrap.connect( network.getSandboxIp(), network.getSandboxPort() ); sandboxChannel = future.channel(); } @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { // Forward to sandbox sandboxChannel.writeAndFlush(msg); } @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { if (sandboxChannel != null) { sandboxChannel.close(); } } } // Data classes public static class IsolatedNetwork { private final String sandboxId; private String vethHost; private String vethSandbox; private InetAddress sandboxIp; private int sandboxPort; private String namespace; // constructor and getters } public static class NetworkConfig { private NetworkMode mode; private int hostPort; private InetAddress allowedSubnet; private List<PortMapping> portMappings; private boolean enableTls; private CertificateConfig tlsConfig; // getters and setters } public enum NetworkMode { ISOLATED, // No external access BRIDGED, // Bridge to host network NATTED, // NAT with host PROXY_ONLY // All traffic through proxy } public static class NetworkPolicy { private PolicyType type; private Map<String, Object> parameters; // getters and setters } public enum PolicyType { FIREWALL, RATE_LIMITING, CONTENT_FILTERING, TLS_INSPECTION } public static class NetworkException extends Exception { public NetworkException(String message) { super(message); } public NetworkException(String message, Throwable cause) { super(message, cause); } } }

6. Filesystem Isolation Service

package com.gvisor.sandbox; import java.io.*; import java.nio.file.*; import java.nio.file.attribute.*; import java.util.*; @Service public class FilesystemIsolationService { /** * Create isolated filesystem for sandbox */ public IsolatedFilesystem createIsolatedFilesystem(String sandboxId, FilesystemConfig config) throws FilesystemException { try { IsolatedFilesystem fs = new IsolatedFilesystem(sandboxId); // Create root directory Path rootPath = createRootDirectory(sandboxId); fs.setRootPath(rootPath); // Create directory structure createDirectoryStructure(rootPath, config); // Mount required filesystems mountFilesystems(rootPath, config); // Set up overlay filesystem setupOverlayFilesystem(rootPath, config); // Apply filesystem policies applyFilesystemPolicies(rootPath, config.getPolicies()); logger.info("Created isolated filesystem for sandbox: {}", sandboxId); return fs; } catch (Exception e) { throw new FilesystemException("Failed to create isolated filesystem", e); } } /** * Setup overlay filesystem for copy-on-write */ private void setupOverlayFilesystem(Path rootPath, FilesystemConfig config) throws IOException { // Create overlay directories Path upperDir = rootPath.resolve("overlay/upper"); Path workDir = rootPath.resolve("overlay/work"); Path mergedDir = rootPath.resolve("merged"); Files.createDirectories(upperDir); Files.createDirectories(workDir); Files.createDirectories(mergedDir); // Mount overlay String mountOptions = String.format( "lowerdir=%s,upperdir=%s,workdir=%s", config.getBaseImagePath(), upperDir.toString(), workDir.toString() ); mount("overlay", mergedDir, "overlay", mountOptions); // Set merged as root Files.move(mergedDir, rootPath.resolve("root")); } /** * Apply filesystem access control policies */ private void applyFilesystemPolicies(Path rootPath, List<FilesystemPolicy> policies) throws IOException { for (FilesystemPolicy policy : policies) { Path targetPath = rootPath.resolve(policy.getPath()); if (Files.exists(targetPath)) { switch (policy.getType()) { case READ_ONLY: makeReadOnly(targetPath); break; case NO_EXECUTE: removeExecutePermission(targetPath); break; case NO_ACCESS: restrictAccess(targetPath, policy.getAllowedUsers()); break; case QUOTA: setQuota(targetPath, policy.getQuotaLimit()); break; } } } } /** * Monitor filesystem activity */ public FilesystemMetrics monitorFilesystemActivity(String sandboxId) throws FilesystemException { FilesystemMetrics metrics = new FilesystemMetrics(); try { Path rootPath = getSandboxRoot(sandboxId); // Get disk usage metrics.setTotalSpace(Files.getFileStore(rootPath).getTotalSpace()); metrics.setUsableSpace(Files.getFileStore(rootPath).getUsableSpace()); // Count files and directories FileCounts counts = countFiles(rootPath); metrics.setFileCount(counts.fileCount); metrics.setDirectoryCount(counts.directoryCount); // Get inode usage metrics.setInodeUsage(getInodeUsage(rootPath)); // Monitor open file descriptors metrics.setOpenFiles(getOpenFiles(sandboxId)); } catch (Exception e) { throw new FilesystemException("Failed to monitor filesystem", e); } return metrics; } /** * Create secure temporary filesystem */ public TempFilesystem createSecureTempFilesystem(String sandboxId, TempConfig config) throws FilesystemException { try { TempFilesystem tempFs = new TempFilesystem(sandboxId); // Create tmpfs mount Path tempPath = createTempfsMount(sandboxId, config.getSizeLimit()); tempFs.setMountPath(tempPath); // Apply security settings applyTempSecurity(tempPath, config); // Set up cleanup setupTempCleanup(tempFs, config.getTtlSeconds()); return tempFs; } catch (Exception e) { throw new FilesystemException("Failed to create temp filesystem", e); } } private void makeReadOnly(Path path) throws IOException { if (Files.isDirectory(path)) { try (DirectoryStream<Path> stream = Files.newDirectoryStream(path)) { for (Path entry : stream) { makeReadOnly(entry); } } } // Remove write permissions Set<PosixFilePermission> perms = Files.getPosixFilePermissions(path); perms.remove(PosixFilePermission.OWNER_WRITE); perms.remove(PosixFilePermission.GROUP_WRITE); perms.remove(PosixFilePermission.OTHERS_WRITE); Files.setPosixFilePermissions(path, perms); } private FileCounts countFiles(Path path) throws IOException { FileCounts counts = new FileCounts(); try (DirectoryStream<Path> stream = Files.newDirectoryStream(path)) { for (Path entry : stream) { if (Files.isDirectory(entry)) { counts.directoryCount++; FileCounts subCounts = countFiles(entry); counts.fileCount += subCounts.fileCount; counts.directoryCount += subCounts.directoryCount; } else { counts.fileCount++; } } } return counts; } // Data classes public static class IsolatedFilesystem { private final String sandboxId; private Path rootPath; private List<MountPoint> mountPoints; private FilesystemConfig config; // constructor and getters } public static class FilesystemConfig { private String baseImagePath; private List<MountPoint> mountPoints; private List<FilesystemPolicy> policies; private boolean enableOverlay; private boolean enableQuotas; // getters and setters } public static class MountPoint { private String source; private String target; private String type; private String options; // getters and setters } public static class FilesystemPolicy { private PolicyType type; private String path; private List<String> allowedUsers; private long quotaLimit; // getters and setters } public enum PolicyType { READ_ONLY, NO_EXECUTE, NO_ACCESS, QUOTA } public static class FileCounts { int fileCount; int directoryCount; } public static class FilesystemException extends Exception { public FilesystemException(String message) { super(message); } public FilesystemException(String message, Throwable cause) { super(message, cause); } } }

7. Docker Integration

# Dockerfile for gVisor-enabled Java application FROM gcr.io/gvisor-images/gvisor-tests:latest AS gvisor FROM eclipse-temurin:17-jdk AS builder # Install gVisor COPY --from=gvisor /usr/local/bin/runsc /usr/local/bin/runsc COPY --from=gvisor /etc/gvisor/ /etc/gvisor/ # Install build dependencies RUN apt-get update && apt-get install -y \ build-essential \ pkg-config \ && rm -rf /var/lib/apt/lists/* WORKDIR /app COPY . . RUN ./mvnw clean package -DskipTests # Runtime image FROM alpine:3.18 # Install gVisor runtime COPY --from=gvisor /usr/local/bin/runsc /usr/local/bin/runsc COPY --from=gvisor /etc/gvisor/ /etc/gvisor/ # Install Java runtime RUN apk add --no-cache openjdk17-jre # Create non-root user RUN addgroup -S appgroup && adduser -S appuser -G appgroup # Copy application COPY --from=builder --chown=appuser:appgroup /app/target/*.jar /app/app.jar # Configure gVisor RUN runsc install --runtime=runsc-gvisor \ --network=none \ --rootless \ --debug-log=/tmp/runsc/ \ --log-packets \ --strace # Switch to non-root user USER appuser # Health check HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \ CMD java -cp /app/app.jar com.gvisor.HealthCheck || exit 1 # Entrypoint with gVisor ENTRYPOINT ["runsc", "run", "--bundle", "/app", "java-app"]

8. Kubernetes Integration

# gvisor-sandbox.yaml apiVersion: v1 kind: Pod metadata: name: java-sandbox-pod annotations: # Use gVisor runtime io.kubernetes.cri-o.runtime: "runsc" spec: runtimeClassName: gvisor securityContext: runAsNonRoot: true runAsUser: 1000 runAsGroup: 1000 seccompProfile: type: RuntimeDefault capabilities: drop: - ALL allowPrivilegeEscalation: false readOnlyRootFilesystem: true containers: - name: java-app image: your-registry/java-app:latest imagePullPolicy: Always # Resource limits resources: limits: memory: "512Mi" cpu: "500m" requests: memory: "256Mi" cpu: "250m" # Security context securityContext: privileged: false allowPrivilegeEscalation: false capabilities: drop: - ALL readOnlyRootFilesystem: true runAsNonRoot: true runAsUser: 1000 runAsGroup: 1000 # Environment variables env: - name: JAVA_OPTS value: "-XX:+UseContainerSupport -XX:MaxRAMPercentage=75.0" # Health checks livenessProbe: exec: command: - java - -cp - /app/app.jar - com.gvisor.HealthCheck initialDelaySeconds: 30 periodSeconds: 10 readinessProbe: exec: command: - java - -cp - /app/app.jar - com.gvisor.ReadinessCheck initialDelaySeconds: 5 periodSeconds: 5 # Volume mounts volumeMounts: - name: tmp mountPath: /tmp readOnly: false - name: config mountPath: /app/config readOnly: true volumes: - name: tmp emptyDir: medium: Memory sizeLimit: 100Mi - name: config configMap: name: app-config

9. Performance Benchmarking

package com.gvisor.benchmark; import org.openjdk.jmh.annotations.*; import java.util.concurrent.TimeUnit; @State(Scope.Benchmark) @BenchmarkMode(Mode.AverageTime) @OutputTimeUnit(TimeUnit.MICROSECONDS) @Warmup(iterations = 3, time = 1) @Measurement(iterations = 5, time = 1) @Fork(2) public class GVisorBenchmark { private GVisorRuntimeManager runtimeManager; private JavaSandboxRunner sandboxRunner; @Setup public void setup() throws Exception { runtimeManager = new GVisorRuntimeManager(); sandboxRunner = new JavaSandboxRunner(); } @Benchmark public void benchmarkSandboxCreation() throws Exception { SandboxConfig config = SandboxConfig.builder() .withIsolationLevel(IsolationLevel.MODERATE) .build(); runtimeManager.createSandbox(config); } @Benchmark public void benchmarkJavaExecution() throws Exception { String testCode = """ public class Test { public static void main(String[] args) { System.out.println("Hello from sandbox!"); } } """; sandboxRunner.runUntrustedCode(testCode, Collections.emptyList(), new ExecutionConstraints() ); } @Benchmark public void benchmarkSystemCallOverhead() throws Exception { // Measure system call overhead long start = System.nanoTime(); for (int i = 0; i < 1000; i++) { // Perform system call through sandbox performSystemCallInSandbox(); } long end = System.nanoTime(); return (end - start) / 1000.0; // nanoseconds per call } }

10. Security Monitoring

package com.gvisor.monitoring; import org.springframework.stereotype.Service; import java.util.concurrent.*; @Service public class SecurityMonitor { private final ConcurrentHashMap<String, SecurityAlert> alerts = new ConcurrentHashMap<>(); private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1); /** * Monitor sandbox for security events */ public void monitorSandbox(String sandboxId) { scheduler.scheduleAtFixedRate(() -> { try { checkForSecurityEvents(sandboxId); checkForAnomalies(sandboxId); checkForPolicyViolations(sandboxId); } catch (Exception e) { logger.error("Failed to monitor sandbox: {}", sandboxId, e); } }, 0, 5, TimeUnit.SECONDS); } /** * Analyze system call patterns */ private void analyzeSystemCalls(String sandboxId, List<SyscallEvent> events) { // Build frequency map Map<String, Integer> frequency = new HashMap<>(); for (SyscallEvent event : events) { frequency.merge(event.getSyscall(), 1, Integer::sum); } // Detect anomalies for (Map.Entry<String, Integer> entry : frequency.entrySet()) { if (entry.getValue() > getThreshold(entry.getKey())) { raiseAlert(sandboxId, "Excessive system calls: " + entry.getKey(), SecurityLevel.HIGH ); } } } /** * Detect container escape attempts */ private void detectEscapeAttempts(String sandboxId, List<SecurityEvent> events) { for (SecurityEvent event : events) { if (isEscapeAttempt(event)) { raiseAlert(sandboxId, "Possible container escape attempt detected", SecurityLevel.CRITICAL ); // Take immediate action terminateSandbox(sandboxId); } } } private boolean isEscapeAttempt(SecurityEvent event) { // Check for dangerous system calls or patterns String syscall = event.getSyscall(); return syscall.equals("ptrace") || syscall.equals("keyctl") || syscall.equals("add_key") || syscall.equals("request_key") || syscall.equals("mount") || syscall.equals("umount2") || syscall.equals("pivot_root"); } }

Best Practices

1. Runtime Configuration

# Optimized runsc configuration runsc install \ --runtime=runsc-opt \ --network=none \ --rootless \ --debug-log=/tmp/runsc/ \ --strace \ --platform=ptrace

2. Security Hardening

// Apply defense-in-depth public void hardenSandbox(SandboxConfig config) { // Multiple layers of security config.setSeccompProfile(createStrictProfile()); config.setCapabilities(Collections.emptyList()); config.setAppArmorProfile("docker-default"); config.setSelinuxLabel("system_u:system_r:container_t:s0"); }

3. Performance Optimization

// Balance security and performance public PerformanceTuning tunePerformance(SandboxMetrics metrics) { if (metrics.getSystemCallOverhead() > 50) { // Switch to KVM platform for better performance return PerformanceTuning.KVM_MODE; } else if (metrics.getMemoryUsage() > 80) { // Reduce memory overhead return PerformanceTuning.MEMORY_OPTIMIZED; } return PerformanceTuning.BALANCED; }

Conclusion

This comprehensive gVisor integration provides:

Secure sandboxing for Java applications
System call interception and filtering
Resource isolation with cgroups and namespaces
Network isolation with virtual interfaces
Filesystem isolation with overlay mounts
Performance monitoring and benchmarking
Kubernetes integration for orchestration

Key benefits:

Strong isolation between host and untrusted code
Compatibility with existing Java applications
Performance close to native execution
Production-ready for enterprise deployment
Extensible architecture for custom policies

This setup enables running untrusted Java code safely while maintaining performance and compatibility with existing infrastructure.

Advanced Java Container Security, Sandboxing & Trusted Runtime Environments

https://macronepal.com/blog/sandboxing-java-applications-implementing-landlock-lsm-for-enhanced-container-security/
Explains using Linux Landlock LSM to sandbox Java applications by restricting file system and resource access without root privileges, improving application-level isolation and reducing attack surface.

https://macronepal.com/blog/gvisor-sandbox-integration-in-java-complete-guide/
Explains integrating gVisor with Java to provide a user-space kernel sandbox that intercepts system calls and isolates applications from the host operating system for stronger security.

https://macronepal.com/blog/selinux-for-java-mandatory-access-control-for-jvm-applications/
Explains how SELinux enforces Mandatory Access Control (MAC) policies on Java applications, strictly limiting what files, processes, and network resources the JVM can access.

https://macronepal.com/java/a-comprehensive-guide-to-intel-sgx-sdk-integration-in-java/
Explains Intel SGX integration in Java, allowing sensitive code and data to run inside secure hardware enclaves that remain protected even if the OS is compromised.

https://macronepal.com/blog/building-a-microvm-runtime-with-aws-firecracker-in-java-a-comprehensive-guide/
Explains using AWS Firecracker microVMs with Java to run workloads in lightweight virtual machines that provide strong isolation with near-container performance efficiency.

https://macronepal.com/blog/enforcing-mandatory-access-control-implementing-apparmor-for-java-applications/
Explains AppArmor security profiles for Java applications, enforcing rules that restrict file access, execution rights, and system-level permissions.

https://macronepal.com/blog/rootless-containers-in-java-secure-container-operations-without-root/
Explains running Java applications in rootless containers using Linux user namespaces so containers operate securely without requiring root privileges.

https://macronepal.com/blog/unlocking-container-security-harnessing-user-namespaces-in-java/
Explains Linux user namespaces, which isolate user and group IDs inside containers to improve privilege separation and enhance container security for Java workloads.

https://macronepal.com/blog/secure-bootstrapping-in-java-comprehensive-trust-establishment-framework/
Explains secure bootstrapping in Java, focusing on how systems establish trust during startup using secure key management, identity verification, and trusted configuration loading.

https://macronepal.com/blog/securing-java-applications-with-chainguard-wolfi-a-comprehensive-guide-2/
Explains using Chainguard/Wolfi minimal container images to secure Java applications by reducing unnecessary packages, minimizing vulnerabilities, and providing a hardened runtime environment.