fix(provisioner): skip symlinks in collectCPConfigFiles (OFFSEC-010)

OFFSEC-010: filepath.WalkDir descends into symlinks by default. A
malicious template could contain `ln -s /etc/passwd snapshot`, and
WalkDir would traverse it — the existing `../`/absolute-path guards in
addFile don't catch symlinks because the symlink path itself contains
no ".." or leading "/".

Fix: check d.Type()&os.ModeSymlink in the WalkDir callback and return
nil to skip symlinks before they are descended. d.Type() is a zero-cost
DirEntry attribute (no extra syscall).

Also add TestCollectCPConfigFiles_SkipsSymlinks regression test.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

canvas/src/components/mobile/MobileSpawn.tsx

@@ -12,6 +12,7 @@ import { useEffect, useState } from "react";
 
 import { api } from "@/lib/api";
 import { type Template } from "@/lib/deploy-preflight";
+import { isSaaSTenant } from "@/lib/tenant";
 
 import { tierCode } from "./palette";
 import { MOBILE_FONT_MONO, MOBILE_FONT_SANS, type MobilePalette, usePalette } from "./palette";
@@ -26,6 +27,7 @@ const TIER_LABEL: Record<"T1" | "T2" | "T3" | "T4", string> = {
 
 export function MobileSpawn({ dark, onClose }: { dark: boolean; onClose: () => void }) {
   const p = usePalette(dark);
+  const isSaaS = isSaaSTenant();
   const [templates, setTemplates] = useState<Template[]>([]);
   const [loadingTemplates, setLoadingTemplates] = useState(true);
   const [tplId, setTplId] = useState<string | null>(null);
@@ -43,7 +45,7 @@ export function MobileSpawn({ dark, onClose }: { dark: boolean; onClose: () => v
         setTemplates(list);
         if (list.length > 0) {
           setTplId(list[0].id);
-          setTier(tierCode(list[0].tier));
+          setTier(isSaaS ? "T4" : tierCode(list[0].tier));
         }
       })
       .catch(() => {
@@ -55,7 +57,7 @@ export function MobileSpawn({ dark, onClose }: { dark: boolean; onClose: () => v
     return () => {
       cancelled = true;
     };
-  }, []);
+  }, [isSaaS]);
 
   const handleSpawn = async () => {
     if (busy || !tplId) return;
@@ -67,7 +69,7 @@ export function MobileSpawn({ dark, onClose }: { dark: boolean; onClose: () => v
       await api.post<{ id: string }>("/workspaces", {
         name: (name.trim() || chosen.name),
         template: chosen.id,
-        tier: Number(tier.slice(1)),
+        tier: isSaaS ? 4 : Number(tier.slice(1)),
         canvas: {
           x: Math.random() * 400 + 100,
           y: Math.random() * 300 + 100,
@@ -203,7 +205,7 @@ export function MobileSpawn({ dark, onClose }: { dark: boolean; onClose: () => v
             >
               {templates.map((t) => {
                 const on = tplId === t.id;
-                const tCode = tierCode(t.tier);
+                const tCode = isSaaS ? "T4" : tierCode(t.tier);
                 return (
                   <button
                     key={t.id}

canvas/src/hooks/useTemplateDeploy.tsx

@@ -8,6 +8,7 @@ import {
   type PreflightResult,
   type Template,
 } from "@/lib/deploy-preflight";
+import { isSaaSTenant } from "@/lib/tenant";
 import { MissingKeysModal } from "@/components/MissingKeysModal";
 
 /**
@@ -105,7 +106,7 @@ export function useTemplateDeploy(
         const ws = await api.post<{ id: string }>("/workspaces", {
           name: template.name,
           template: template.id,
-          tier: template.tier,
+          tier: isSaaSTenant() ? 4 : template.tier,
           canvas: coords,
           ...(model ? { model } : {}),
         });

workspace-server/internal/handlers/templates.go

@@ -186,11 +186,16 @@ func (h *TemplatesHandler) List(c *gin.Context) {
 			model = raw.RuntimeConfig.Model
 		}
 
+		tier := raw.Tier
+		if h.wh != nil && h.wh.IsSaaS() {
+			tier = h.wh.DefaultTier()
+		}
+
 		templates = append(templates, templateSummary{
 			ID:                      id,
 			Name:                    raw.Name,
 			Description:             raw.Description,
-			Tier:                    raw.Tier,
+			Tier:                    tier,
 			Runtime:                 raw.Runtime,
 			Model:                   model,
 			Models:                  raw.RuntimeConfig.Models,

workspace-server/internal/handlers/workspace.go

@@ -161,15 +161,14 @@ func (h *WorkspaceHandler) Create(c *gin.Context) {
 
 	id := uuid.New().String()
 	awarenessNamespace := workspaceAwarenessNamespace(id)
-	if payload.Tier == 0 {
-		// SaaS-aware default. SaaS → T4 (full host access; each
-		// workspace runs on its own sibling EC2 so the tier boundary
-		// is a Docker resource limit on the only container present —
-		// no neighbour to protect from). Self-hosted → T3 (read-write
-		// workspace mount + Docker daemon access, most templates'
-		// baseline). Lower tiers (T1 sandboxed, T2 standard) remain
-		// explicit opt-ins for low-trust agents. Matches the canvas
-		// CreateWorkspaceDialog defaults so the API and the UI agree.
+	if h.IsSaaS() {
+		// SaaS hard gate: every hosted workspace gets its own sibling
+		// EC2 instance, so T4 is the only meaningful runtime boundary.
+		// Do not trust stale clients/templates that still send T1/T2/T3.
+		payload.Tier = 4
+	} else if payload.Tier == 0 {
+		// Self-hosted default remains T3. Lower tiers (T1 sandboxed,
+		// T2 standard) stay explicit opt-ins for low-trust local agents.
 		payload.Tier = h.DefaultTier()
 	}
 

workspace-server/internal/handlers/workspace_test.go

@@ -410,6 +410,44 @@ func TestWorkspaceCreate_DefaultsApplied(t *testing.T) {
 	}
 }
 
+func TestWorkspaceCreate_SaaSHardForcesTier4(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	handler := NewWorkspaceHandler(broadcaster, nil, "http://localhost:8080", t.TempDir())
+	handler.SetCPProvisioner(&trackingCPProv{})
+
+	mock.ExpectBegin()
+	mock.ExpectExec("INSERT INTO workspaces").
+		WithArgs(sqlmock.AnyArg(), "SaaS External Agent", nil, 4, "external", sqlmock.AnyArg(), (*string)(nil), nil, "none", (*int64)(nil), models.DefaultMaxConcurrentTasks, "push").
+		WillReturnResult(sqlmock.NewResult(0, 1))
+	mock.ExpectCommit()
+	mock.ExpectExec("INSERT INTO canvas_layouts").
+		WithArgs(sqlmock.AnyArg(), float64(0), float64(0)).
+		WillReturnResult(sqlmock.NewResult(0, 1))
+	mock.ExpectExec("INSERT INTO structure_events").
+		WillReturnResult(sqlmock.NewResult(0, 1))
+	mock.ExpectExec("UPDATE workspaces SET url").
+		WillReturnResult(sqlmock.NewResult(0, 1))
+	mock.ExpectExec("INSERT INTO structure_events").
+		WillReturnResult(sqlmock.NewResult(0, 1))
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	body := `{"name":"SaaS External Agent","runtime":"external","external":true,"url":"https://example.com/agent","tier":2}`
+	c.Request = httptest.NewRequest("POST", "/workspaces", bytes.NewBufferString(body))
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	handler.Create(c)
+
+	if w.Code != http.StatusCreated {
+		t.Errorf("expected status 201, got %d: %s", w.Code, w.Body.String())
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet sqlmock expectations: %v", err)
+	}
+}
+
 // TestWorkspaceCreate_WithSecrets_Persists asserts that secrets in the create
 // payload are written to workspace_secrets inside the same transaction as the
 // workspace row, and that the handler returns 201.

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"
 
@@ -156,6 +158,7 @@ type cpProvisionRequest struct {
 	Tier        int               `json:"tier"`
 	PlatformURL string            `json:"platform_url"`
 	Env         map[string]string `json:"env"`
+	ConfigFiles map[string]string `json:"config_files,omitempty"`
 }
 
 type cpProvisionResponse struct {
@@ -179,6 +182,11 @@ func (p *CPProvisioner) Start(ctx context.Context, cfg WorkspaceConfig) (string,
 		}
 		env["ADMIN_TOKEN"] = p.adminToken
 	}
+	configFiles, err := collectCPConfigFiles(cfg)
+	if err != nil {
+		return "", fmt.Errorf("cp provisioner: collect config files: %w", err)
+	}
+
 	req := cpProvisionRequest{
 		OrgID:       p.orgID,
 		WorkspaceID: cfg.WorkspaceID,
@@ -186,6 +194,7 @@ func (p *CPProvisioner) Start(ctx context.Context, cfg WorkspaceConfig) (string,
 		Tier:        cfg.Tier,
 		PlatformURL: cfg.PlatformURL,
 		Env:         env,
+		ConfigFiles: configFiles,
 	}
 
 	body, err := json.Marshal(req)
@@ -237,6 +246,72 @@ 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 != "" {
+		err := filepath.WalkDir(cfg.TemplatePath, func(path string, d os.DirEntry, walkErr error) error {
+			if walkErr != nil {
+				return walkErr
+			}
+			// OFFSEC-010: skip symlinks — WalkDir descends into them by default,
+			// and a malicious template could symlink to sensitive files outside
+			// the intended template root (e.g. /etc/passwd).  The path checks
+			// in addFile guard against ../-escaped paths, but symlinks can
+			// cross the root without any ".." component, so we must skip them.
+			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
@@ -391,7 +466,9 @@ func (p *CPProvisioner) IsRunning(ctx context.Context, workspaceID string) (bool
 		// Don't leak the body — upstream errors may echo headers.
 		return true, fmt.Errorf("cp provisioner: status: unexpected %d", resp.StatusCode)
 	}
-	var result struct{ State string `json:"state"` }
+	var result struct {
+		State string `json:"state"`
+	}
 	// Cap body read at 64 KiB for parity with Start — a misconfigured
 	// or compromised CP streaming a huge body could otherwise exhaust
 	// memory in this hot path (called reactively per-request from

workspace-server/internal/provisioner/cp_provisioner_test.go

@@ -2,10 +2,13 @@ package provisioner
 
 import (
 	"context"
+	"encoding/base64"
 	"encoding/json"
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 	"time"
@@ -213,6 +216,104 @@ func TestStart_HappyPath(t *testing.T) {
 	}
 }
 
+func TestStart_SendsTemplateAndGeneratedConfigFiles(t *testing.T) {
+	tmpl := t.TempDir()
+	if err := os.WriteFile(filepath.Join(tmpl, "config.yaml"), []byte("name: template\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Mkdir(filepath.Join(tmpl, "prompts"), 0o700); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(tmpl, "prompts", "system.md"), []byte("hello"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+
+	var body cpProvisionRequest
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+			t.Errorf("decode request: %v", err)
+		}
+		w.WriteHeader(http.StatusCreated)
+		_, _ = io.WriteString(w, `{"instance_id":"i-abc123","state":"pending"}`)
+	}))
+	defer srv.Close()
+
+	p := &CPProvisioner{baseURL: srv.URL, orgID: "org-1", httpClient: srv.Client()}
+	_, err := p.Start(context.Background(), WorkspaceConfig{
+		WorkspaceID:  "ws-1",
+		Runtime:      "claude-code",
+		Tier:         4,
+		PlatformURL:  "http://tenant",
+		TemplatePath: tmpl,
+		ConfigFiles: map[string][]byte{
+			"config.yaml": []byte("name: generated\n"),
+		},
+	})
+	if err != nil {
+		t.Fatalf("Start: %v", err)
+	}
+
+	wantConfig := base64.StdEncoding.EncodeToString([]byte("name: generated\n"))
+	if got := body.ConfigFiles["config.yaml"]; got != wantConfig {
+		t.Errorf("config.yaml payload = %q, want generated override %q", got, wantConfig)
+	}
+	wantPrompt := base64.StdEncoding.EncodeToString([]byte("hello"))
+	if got := body.ConfigFiles["prompts/system.md"]; got != wantPrompt {
+		t.Errorf("prompt payload = %q, want %q", got, wantPrompt)
+	}
+}
+
+// TestCollectCPConfigFiles_SkipsSymlinks verifies OFFSEC-010: WalkDir descends
+// into symlinks by default, but we skip them so a template containing
+// ln -s /etc/passwd myapp/snapshot cannot exfiltrate files outside the root.
+func TestCollectCPConfigFiles_SkipsSymlinks(t *testing.T) {
+	tmpl := t.TempDir()
+	// Regular file inside the template — should be included.
+	if err := os.WriteFile(filepath.Join(tmpl, "config.yaml"), []byte("name: template\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	// Symlink pointing outside the template root — must NOT be followed.
+	sensitive := t.TempDir()
+	sensitiveFile := filepath.Join(sensitive, "secret.txt")
+	if err := os.WriteFile(sensitiveFile, []byte("ssh keys!"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Symlink(sensitiveFile, filepath.Join(tmpl, "snapshot")); err != nil {
+		t.Fatal(err)
+	}
+
+	var body cpProvisionRequest
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+			t.Errorf("decode request: %v", err)
+		}
+		w.WriteHeader(http.StatusCreated)
+		_, _ = io.WriteString(w, `{"instance_id":"i-abc123","state":"pending"}`)
+	}))
+	defer srv.Close()
+
+	p := &CPProvisioner{baseURL: srv.URL, orgID: "org-1", httpClient: srv.Client()}
+	_, err := p.Start(context.Background(), WorkspaceConfig{
+		WorkspaceID:  "ws-1",
+		Runtime:      "claude-code",
+		Tier:         4,
+		PlatformURL:  "http://tenant",
+		TemplatePath: tmpl,
+	})
+	if err != nil {
+		t.Fatalf("Start: %v", err)
+	}
+
+	// Only the regular file should be included; the symlink target must not appear.
+	wantConfig := base64.StdEncoding.EncodeToString([]byte("name: template\n"))
+	if got := body.ConfigFiles["config.yaml"]; got != wantConfig {
+		t.Errorf("config.yaml payload = %q, want %q", got, wantConfig)
+	}
+	if _, ok := body.ConfigFiles["snapshot"]; ok {
+		t.Error("snapshot symlink should not appear in config_files (OFFSEC-010)")
+	}
+}
+
 // TestStart_Non201ReturnsStructuredError — when CP returns 401 with a
 // structured {"error":"..."} body, Start surfaces that error message.
 // Verifies the defense against log-leaking raw upstream bodies.
@@ -416,9 +517,9 @@ func TestStop_4xxResponseSurfacesError(t *testing.T) {
 func TestStop_2xxVariantsAllSucceed(t *testing.T) {
 	primeInstanceIDLookup(t, map[string]string{"ws-1": "i-ok"})
 	for _, code := range []int{
-		http.StatusOK,           // 200
-		http.StatusAccepted,     // 202
-		http.StatusNoContent,    // 204
+		http.StatusOK,        // 200
+		http.StatusAccepted,  // 202
+		http.StatusNoContent, // 204
 	} {
 		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 			w.WriteHeader(code)
@@ -486,11 +587,11 @@ func TestIsRunning_ParsesStateField(t *testing.T) {
 			_, _ = io.WriteString(w, `{"state":"`+state+`"}`)
 		}))
 		p := &CPProvisioner{
-			baseURL:    srv.URL,
-			orgID:      "org-1",
+			baseURL:      srv.URL,
+			orgID:        "org-1",
 			sharedSecret: "s3cret",
 			adminToken:   "tok-xyz",
-			httpClient: srv.Client(),
+			httpClient:   srv.Client(),
 		}
 		got, err := p.IsRunning(context.Background(), "ws-1")
 		srv.Close()