335 lines
9.5 KiB
Go
335 lines
9.5 KiB
Go
package main
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import (
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"bytes"
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"context"
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"fmt"
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"io"
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"os"
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"os/exec"
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"path/filepath"
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"regexp"
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"strings"
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"sync"
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"time"
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"anvillm/internal/sandbox"
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)
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var dangerousPatterns = []*regexp.Regexp{
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regexp.MustCompile(`rm\s+(-[a-z]*r[a-z]*\s+)*-[a-z]*f[a-z]*\s*/(home|var|usr|etc|boot|root|bin|sbin|lib|opt|srv)?`), // rm -rf, rm -r -f on sensitive paths
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regexp.MustCompile(`rm\s+(-[a-z]*f[a-z]*\s+)*-[a-z]*r[a-z]*\s*/(home|var|usr|etc|boot|root|bin|sbin|lib|opt|srv)?`), // rm -fr, rm -f -r on sensitive paths
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regexp.MustCompile(`rm\s+.*--recursive.*--force`), // rm --recursive --force
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regexp.MustCompile(`rm\s+.*--force.*--recursive`), // rm --force --recursive
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regexp.MustCompile(`rm\s+(-[a-z]*r[a-z]*\s+)*-[a-z]*f[a-z]*\s+\.\.?(/|$)`), // rm -rf ./ or rm -rf ../
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regexp.MustCompile(`rm\s+(-[a-z]*r[a-z]*\s+)*-[a-z]*f[a-z]*\s+~`), // rm -rf ~ (home dir)
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regexp.MustCompile(`rm\s+(-[a-z]*r[a-z]*\s+)*-[a-z]*f[a-z]*\s+\*`), // rm -rf * (glob expansion)
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regexp.MustCompile(`:\s*\(\s*\)\s*\{\s*:\s*\|\s*:\s*&`), // fork bomb
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regexp.MustCompile(`\bmkfs\b`), // filesystem format
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regexp.MustCompile(`\bdd\b.*\bif=/dev/`), // dd from device
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regexp.MustCompile(`>\s*/dev/sd`), // write to block device
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regexp.MustCompile(`\beval\s+".*\$`), // eval with variable expansion
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regexp.MustCompile(`\b(sudo|su)\s`), // privilege escalation
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regexp.MustCompile(`/etc/(shadow|sudoers)`), // sensitive files (not passwd)
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}
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var whitespacePattern = regexp.MustCompile(`\s+`)
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// Rate limiting for validation failures
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var (
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rateLimitMu sync.Mutex
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validationFailures int
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lastFailure time.Time
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blockedUntil time.Time
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)
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const (
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maxFailures = 5
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blockDuration = 30 * time.Second
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failureWindow = 60 * time.Second
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)
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func checkRateLimit() error {
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rateLimitMu.Lock()
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defer rateLimitMu.Unlock()
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now := time.Now()
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if now.Before(blockedUntil) {
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remaining := blockedUntil.Sub(now).Round(time.Second)
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return fmt.Errorf("rate limited: too many validation failures, blocked for %v", remaining)
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}
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return nil
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}
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func recordValidationFailure() {
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rateLimitMu.Lock()
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defer rateLimitMu.Unlock()
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now := time.Now()
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// Reset counter if outside failure window
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if now.Sub(lastFailure) > failureWindow {
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validationFailures = 0
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}
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validationFailures++
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lastFailure = now
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if validationFailures >= maxFailures {
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blockedUntil = now.Add(blockDuration)
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validationFailures = 0
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logSecurityEvent(SecurityEvent{
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Timestamp: now,
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EventType: "rate_limit_triggered",
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Details: fmt.Sprintf("blocked for %v after %d failures", blockDuration, maxFailures),
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})
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}
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}
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func isPermissionError(err error) bool {
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if err == nil {
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return false
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}
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msg := strings.ToLower(err.Error())
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return strings.Contains(msg, "permission denied") ||
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strings.Contains(msg, "no such file or directory")
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}
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func validateCode(code string) error {
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if err := checkRateLimit(); err != nil {
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return err
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}
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// Normalize: collapse whitespace, lowercase for pattern matching
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normalized := strings.ToLower(code)
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normalized = whitespacePattern.ReplaceAllString(normalized, " ")
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for _, pattern := range dangerousPatterns {
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if pattern.MatchString(normalized) {
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recordValidationFailure()
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logSecurityEvent(SecurityEvent{
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Timestamp: time.Now(),
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EventType: "validation_failure",
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Details: fmt.Sprintf("dangerous pattern: %s", pattern.String()),
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})
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return fmt.Errorf("dangerous pattern detected")
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}
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}
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return nil
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}
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// loadLayeredConfig loads sandbox config using the layered approach:
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// global.yaml -> backend (anvilmcp) -> sandbox/<name>.yaml
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func loadLayeredConfig(name string) (*sandbox.Config, error) {
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// Load global.yaml as base
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baseCfg, err := sandbox.Load()
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if err != nil {
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return nil, fmt.Errorf("failed to load global config: %w", err)
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}
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// Convert base config to layered format
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baseLayer := sandbox.LayeredConfig{
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Filesystem: baseCfg.Filesystem,
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Network: baseCfg.Network,
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Env: baseCfg.Env,
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}
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layers := []sandbox.LayeredConfig{baseLayer}
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// Load sandbox layer
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if name == "" {
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name = "anvilmcp"
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}
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sbxLayer, err := sandbox.LoadSandbox(name)
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if err != nil {
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return nil, fmt.Errorf("failed to load sandbox %q: %w", name, err)
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}
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layers = append(layers, sbxLayer)
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// Merge layers
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general := sandbox.GeneralConfig{
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BestEffort: baseCfg.General.BestEffort,
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LogLevel: baseCfg.General.LogLevel,
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}
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advanced := sandbox.AdvancedConfig{
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LDD: baseCfg.Advanced.LDD,
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AddExec: baseCfg.Advanced.AddExec,
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}
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return sandbox.Merge(general, advanced, layers...), nil
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}
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func executeCode(code, language string, timeout int, sandboxName string) (string, error) {
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start := time.Now()
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if timeout <= 0 {
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timeout = 30
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}
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if err := validateCode(code); err != nil {
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logExecution(ExecutionLog{
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Timestamp: start,
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CodeHash: hashCode(code),
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Language: language,
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Duration: time.Since(start),
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Success: false,
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OutputSize: 0,
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Error: err.Error(),
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})
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return "", err
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}
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// Load layered sandbox config
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cfg, err := loadLayeredConfig(sandboxName)
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if err != nil {
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return "", err
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}
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homeDir, err := os.UserHomeDir()
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if err != nil {
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return "", fmt.Errorf("failed to get home dir: %v", err)
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}
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// Use current working directory
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workDir, _ := os.Getwd()
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// For anvilmcp sandbox, use temp workspace
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var cleanupWorkDir bool
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if sandboxName == "" || sandboxName == "anvilmcp" {
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workspaceBase := filepath.Join(homeDir, ".cache", "anvillm", "exec")
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if err := os.MkdirAll(workspaceBase, 0700); err != nil {
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return "", fmt.Errorf("failed to create workspace base: %v", err)
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}
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workDir, err = os.MkdirTemp(workspaceBase, "anvilmcp-*")
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if err != nil {
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return "", fmt.Errorf("failed to create workspace: %v", err)
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}
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cleanupWorkDir = true
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}
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if cleanupWorkDir {
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defer os.RemoveAll(workDir)
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}
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ctx, cancel := context.WithTimeout(context.Background(), time.Duration(timeout)*time.Second)
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defer cancel()
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landrunPath, err := exec.LookPath("landrun")
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if err != nil {
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return "", fmt.Errorf("landrun not found: %v", err)
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}
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var cmd *exec.Cmd
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switch language {
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case "bash", "":
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args := []string{}
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// Add filesystem permissions from config
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addPaths := func(flag string, paths []string) {
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for _, p := range paths {
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expanded := sandbox.ExpandPath(p, workDir)
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if expanded == "" || strings.Contains(expanded, "{") {
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continue // Skip unexpanded templates
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}
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if _, err := os.Stat(expanded); err == nil {
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args = append(args, flag, expanded)
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}
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}
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}
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addPaths("--ro", cfg.Filesystem.RO)
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addPaths("--rox", cfg.Filesystem.ROX)
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addPaths("--rw", cfg.Filesystem.RW)
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addPaths("--rwx", cfg.Filesystem.RWX)
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// Network
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if cfg.Network.Unrestricted {
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args = append(args, "--unrestricted-network")
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}
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// Environment variables
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for _, env := range cfg.Env {
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if os.Getenv(env) != "" || env == "HOME" || env == "USER" || env == "PATH" {
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args = append(args, "--env", env)
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}
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}
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args = append(args, "--", "bash", "-c", code)
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cmd = exec.CommandContext(ctx, landrunPath, args...)
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cmd.Dir = workDir
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default:
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return "", fmt.Errorf("unsupported language: %s (only bash supported)", language)
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}
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// Limit output size (10MB)
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var outputBuf bytes.Buffer
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lw := &limitedWriter{w: &outputBuf, limit: 10 * 1024 * 1024}
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cmd.Stdout = lw
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cmd.Stderr = lw
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err = cmd.Run()
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output := outputBuf.Bytes()
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if lw.truncated {
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output = append(output, []byte("\n[output truncated at 10MB]")...)
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}
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duration := time.Since(start)
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execLog := ExecutionLog{
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Timestamp: start,
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CodeHash: hashCode(code),
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Language: language,
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Duration: duration,
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Success: err == nil && ctx.Err() != context.DeadlineExceeded,
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OutputSize: len(output),
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}
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if ctx.Err() == context.DeadlineExceeded {
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execLog.Error = fmt.Sprintf("execution timeout after %d seconds", timeout)
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logExecution(execLog)
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logSecurityEvent(SecurityEvent{
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Timestamp: start,
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EventType: "timeout",
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Language: language,
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Details: fmt.Sprintf("timeout after %d seconds", timeout),
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})
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return "", fmt.Errorf("execution timeout after %d seconds", timeout)
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}
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if err != nil {
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execLog.Error = err.Error()
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logExecution(execLog)
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return string(output), fmt.Errorf("execution failed: %v\nOutput: %s", err, string(output))
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}
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logExecution(execLog)
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return string(output), nil
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}
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type limitedWriter struct {
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w io.Writer
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written int
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limit int
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truncated bool
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}
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func (lw *limitedWriter) Write(p []byte) (n int, err error) {
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if lw.written >= lw.limit {
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lw.truncated = true
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return len(p), nil // Discard, report all bytes consumed
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}
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remaining := lw.limit - lw.written
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toWrite := p
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if len(p) > remaining {
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toWrite = p[:remaining]
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lw.truncated = true
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}
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written, err := lw.w.Write(toWrite)
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lw.written += written
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if err != nil {
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return written, err
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}
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return len(p), nil // Report all input bytes as consumed
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}
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