workspace-server/internal/provisioner/cp_provisioner.go

@@ -4,12 +4,14 @@ import (
 	"bytes"
 	"context"
 	"database/sql"
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"io"
 	"log"
 	"net/http"
 	"os"
+	"path/filepath"
 	"strings"
 	"time"
 
@@ -237,6 +239,81 @@ func (p *CPProvisioner) Start(ctx context.Context, cfg WorkspaceConfig) (string,
 	return result.InstanceID, nil
 }
 
+const cpConfigFilesMaxBytes = 12 << 10
+
+func collectCPConfigFiles(cfg WorkspaceConfig) (map[string]string, error) {
+	files := make(map[string]string)
+	total := 0
+	addFile := func(name string, data []byte) error {
+		name = filepath.ToSlash(filepath.Clean(name))
+		if name == "." || strings.HasPrefix(name, "../") || strings.HasPrefix(name, "/") || strings.Contains(name, "/../") {
+			return fmt.Errorf("invalid config file path %q", name)
+		}
+		total += len(data)
+		if total > cpConfigFilesMaxBytes {
+			return fmt.Errorf("config files exceed %d bytes", cpConfigFilesMaxBytes)
+		}
+		files[name] = base64.StdEncoding.EncodeToString(data)
+		return nil
+	}
+
+	if cfg.TemplatePath != "" {
+		// Reject symlinks on the root itself — WalkDir follows symlinks,
+		// so a symlink TemplatePath that escapes the intended root directory
+		// would bypass the subsequent path-relativization checks below.
+		rootInfo, err := os.Lstat(cfg.TemplatePath)
+		if err != nil {
+			return nil, fmt.Errorf("collectCPConfigFiles: lstat template path: %w", err)
+		}
+		if rootInfo.Mode()&os.ModeSymlink != 0 {
+			return nil, fmt.Errorf("collectCPConfigFiles: template path must not be a symlink")
+		}
+		err = filepath.WalkDir(cfg.TemplatePath, func(path string, d os.DirEntry, walkErr error) error {
+			if walkErr != nil {
+				return walkErr
+			}
+			// Skip symlinks — WalkDir follows them by default, which means
+			// a symlink inside the template dir pointing to /etc/passwd
+			// would be traversed even though the resulting relative-path
+			// check would correctly reject it. Defense-in-depth: don't
+			// follow symlinks at all. (OFFSEC-010)
+			if d.Type()&os.ModeSymlink != 0 {
+				return nil
+			}
+			if d.IsDir() {
+				return nil
+			}
+			info, err := d.Info()
+			if err != nil {
+				return err
+			}
+			if !info.Mode().IsRegular() {
+				return nil
+			}
+			rel, err := filepath.Rel(cfg.TemplatePath, path)
+			if err != nil {
+				return err
+			}
+			data, err := os.ReadFile(path)
+			if err != nil {
+				return err
+			}
+			return addFile(rel, data)
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+	for name, data := range cfg.ConfigFiles {
+		if err := addFile(name, data); err != nil {
+			return nil, err
+		}
+	}
+	if len(files) == 0 {
+		return nil, nil
+	}
+	return files, nil
+}
 // Stop terminates the workspace's EC2 instance via the control plane.
 //
 // Looks up the actual EC2 instance_id from the workspaces table before

workspace-server/internal/provisioner/cp_provisioner_test.go

@@ -842,3 +842,67 @@ func TestIsRunning_EmptyInstanceIDReturnsFalse(t *testing.T) {
 		t.Errorf("IsRunning with empty instance_id should return running=false, got true")
 	}
 }
+
+// TestCollectCPConfigFiles_SkipsSymlinks — WalkDir follows symlinks by default,
+// but collectCPConfigFiles must skip them so a symlink inside a template dir
+// pointing outside (e.g. ln -s /etc snapshot) cannot be traversed.
+// Verifies OFFSEC-010 defense-in-depth fix. (OFFSEC-010)
+func TestCollectCPConfigFiles_SkipsSymlinks(t *testing.T) {
+	tmpl := t.TempDir()
+	// Write a real file that should be included.
+	if err := os.WriteFile(filepath.Join(tmpl, "config.yaml"), []byte("name: real\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	// Create a subdir with a file that will be symlinked-outside.
+	sensitiveDir := t.TempDir()
+	if err := os.WriteFile(filepath.Join(sensitiveDir, "secret.txt"), []byte("SENSITIVE\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	// Symlink inside template dir pointing to outside path.
+	symlinkPath := filepath.Join(tmpl, "snapshot")
+	if err := os.Symlink(sensitiveDir, symlinkPath); err != nil {
+		t.Fatal(err)
+	}
+
+	files, err := collectCPConfigFiles(WorkspaceConfig{TemplatePath: tmpl})
+	if err != nil {
+		t.Fatalf("collectCPConfigFiles: %v", err)
+	}
+	if files == nil {
+		t.Fatal("files should not be nil")
+	}
+	// config.yaml must be present.
+	if _, ok := files["config.yaml"]; !ok {
+		t.Errorf("config.yaml missing from files")
+	}
+	// The symlinked path must NOT be included (even though WalkDir would
+	// traverse it, the d.Type()&os.ModeSymlink guard skips the entry).
+	for k := range files {
+		if strings.Contains(k, "snapshot") || strings.Contains(k, "secret") {
+			t.Errorf("symlink path %q should not be in files — OFFSEC-010 regression", k)
+		}
+	}
+}
+
+// TestCollectCPConfigFiles_RejectsRootSymlink — if cfg.TemplatePath itself is
+// a symlink, WalkDir would follow it to an arbitrary directory, bypassing the
+// cfg.TemplatePath boundary. The function must reject this case explicitly.
+// (OFFSEC-010)
+func TestCollectCPConfigFiles_RejectsRootSymlink(t *testing.T) {
+	real := t.TempDir()
+	if err := os.WriteFile(filepath.Join(real, "config.yaml"), []byte("name: real\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	link := filepath.Join(t.TempDir(), "template-link")
+	if err := os.Symlink(real, link); err != nil {
+		t.Fatal(err)
+	}
+
+	_, err := collectCPConfigFiles(WorkspaceConfig{TemplatePath: link})
+	if err == nil {
+		t.Error("collectCPConfigFiles with symlink TemplatePath should return error")
+	}
+	if err != nil && !strings.Contains(err.Error(), "symlink") {
+		t.Errorf("expected symlink-related error, got: %v", err)
+	}
+}