feat(upload): reuse MIME validator for workflow template uploads.

Centralize template extension, magic-byte, and HTML/script rejection in upload.ValidateTemplate so admin template POST matches project asset hardening.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/server/admin_template_handlers.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"errors"
 	"io"
 	"net/http"
 	"strings"
@@ -23,7 +24,11 @@ func (s *Server) handleAdminTemplates(w http.ResponseWriter, r *http.Request) {
 		}
 		writeJSONResponse(w, http.StatusOK, map[string]any{"templates": assets})
 	case http.MethodPost:
-		if err := r.ParseMultipartForm(32 << 20); err != nil {
+		if err := r.ParseMultipartForm(defaultUploadBodyLimit); err != nil {
+			if isRequestBodyTooLarge(err) {
+				http.Error(w, "upload too large", http.StatusRequestEntityTooLarge)
+				return
+			}
 			http.Error(w, "invalid multipart", http.StatusBadRequest)
 			return
 		}
@@ -49,7 +54,10 @@ func (s *Server) handleAdminTemplates(w http.ResponseWriter, r *http.Request) {
 		tv, err := s.wfDefSvc.UploadTemplate(r.Context(), assetKey, name, data, header.Filename, user.ID)
 		if err != nil {
 			status := http.StatusBadRequest
-			if err == workflowdef.ErrNotAvailable {
+			switch {
+			case errors.Is(err, workflowdef.ErrUploadRejected):
+				status = http.StatusUnsupportedMediaType
+			case errors.Is(err, workflowdef.ErrNotAvailable):
 				status = http.StatusServiceUnavailable
 			}
 			http.Error(w, err.Error(), status)

internal/server/body_limit_middleware.go

@@ -29,7 +29,7 @@ func isUploadPath(path string) bool {
 	if strings.HasSuffix(path, "/assets") {
 		return true
 	}
-	return strings.Contains(path, "/admin/templates") && strings.HasSuffix(path, "/upload")
+	return strings.Contains(path, "/admin/templates")
 }
 
 func isRequestBodyTooLarge(err error) bool {

internal/upload/validate.go

@@ -10,6 +10,14 @@ import (
 
 const maxFilenameRunes = 200
 
+// 工作流模板上传允许的扩展名 → 期望 MIME。
+var allowedTemplateExt = map[string]string{
+	".md":   "text/markdown",
+	".docx": "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+	".xlsx": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+	".pptx": "application/vnd.openxmlformats-officedocument.presentationml.presentation",
+}
+
 // 项目材料上传允许的扩展名 → 期望 MIME。
 var allowedMaterialExt = map[string]string{
 	".txt":  "text/plain",
@@ -68,6 +76,46 @@ func ValidateProjectMaterial(filename, declaredMIME string, data []byte) (string
 	return expectedMIME, nil
 }
 
+// ValidateTemplate 校验工作流模板文件名、扩展名白名单与内容魔数/MIME。
+func ValidateTemplate(filename, declaredMIME string, data []byte) (string, error) {
+	base := filepath.Base(strings.TrimSpace(filename))
+	if base == "" || base == "." || base == ".." {
+		return "", fmt.Errorf("invalid filename")
+	}
+	if utf8.RuneCountInString(base) > maxFilenameRunes {
+		return "", fmt.Errorf("filename too long")
+	}
+	ext := strings.ToLower(filepath.Ext(base))
+	expectedMIME, ok := allowedTemplateExt[ext]
+	if !ok {
+		return "", fmt.Errorf("file type not allowed: %s", ext)
+	}
+	if len(data) == 0 {
+		return "", fmt.Errorf("empty file")
+	}
+	if len(data) > 32*1024*1024 {
+		return "", fmt.Errorf("file too large")
+	}
+	if err := rejectDangerousContent(data); err != nil {
+		return "", err
+	}
+	if looksLikeHTML(data) {
+		return "", fmt.Errorf("html content rejected")
+	}
+	detected := http.DetectContentType(data)
+	if _, blocked := blockedDetectedMIME[detected]; blocked {
+		return "", fmt.Errorf("dangerous content type detected: %s", detected)
+	}
+	if err := assertExtensionMatchesContent(ext, data, detected); err != nil {
+		return "", err
+	}
+	declaredMIME = strings.TrimSpace(strings.Split(declaredMIME, ";")[0])
+	if declaredMIME != "" && !mimeCompatible(declaredMIME, expectedMIME, detected) {
+		return "", fmt.Errorf("declared content type mismatch")
+	}
+	return expectedMIME, nil
+}
+
 func looksLikeHTML(data []byte) bool {
 	sample := strings.ToLower(strings.TrimSpace(string(data[:min(len(data), 512)])))
 	return strings.HasPrefix(sample, "<!doctype") ||
@@ -96,7 +144,7 @@ func assertExtensionMatchesContent(ext string, data []byte, detected string) err
 		if !bytesHasPrefix(data, []byte("%PDF")) {
 			return fmt.Errorf("pdf magic mismatch")
 		}
-	case ".docx", ".xlsx":
+	case ".docx", ".xlsx", ".pptx":
 		if !bytesHasPrefix(data, []byte("PK\x03\x04")) {
 			return fmt.Errorf("office document magic mismatch")
 		}
@@ -121,8 +169,12 @@ func mimeCompatible(declared, expected, detected string) bool {
 	if strings.HasPrefix(detected, "text/") && strings.HasPrefix(expected, "text/") {
 		return true
 	}
-	if detected == "application/zip" && (expected == allowedMaterialExt[".docx"] || expected == allowedMaterialExt[".xlsx"]) {
-		return true
+	if detected == "application/zip" {
+		switch expected {
+		case allowedMaterialExt[".docx"], allowedMaterialExt[".xlsx"],
+			allowedTemplateExt[".docx"], allowedTemplateExt[".xlsx"], allowedTemplateExt[".pptx"]:
+			return true
+		}
 	}
 	if detected == "application/octet-stream" {
 		return declared == expected || declared == "application/octet-stream"

internal/upload/validate_test.go

@@ -42,3 +42,35 @@ func TestValidateProjectMaterial_AcceptsPDF(t *testing.T) {
 		t.Fatalf("pdf: %v", err)
 	}
 }
+
+func TestValidateTemplate_AcceptsMarkdown(t *testing.T) {
+	mime, err := ValidateTemplate("brief.md", "text/markdown", []byte("# Title\n\nBody"))
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if mime != "text/markdown" {
+		t.Fatalf("mime=%s", mime)
+	}
+}
+
+func TestValidateTemplate_RejectsHTML(t *testing.T) {
+	data := []byte("<html><script>alert(1)</script></html>")
+	_, err := ValidateTemplate("evil.md", "text/markdown", data)
+	if err == nil {
+		t.Fatal("expected rejection for html content")
+	}
+}
+
+func TestValidateTemplate_RejectsFakeOfficeDoc(t *testing.T) {
+	_, err := ValidateTemplate("fake.docx", "", []byte("not a zip"))
+	if err == nil {
+		t.Fatal("expected office magic rejection")
+	}
+}
+
+func TestValidateTemplate_AcceptsOfficeZipMagic(t *testing.T) {
+	_, err := ValidateTemplate("deck.pptx", "", []byte("PK\x03\x04fake-pptx"))
+	if err != nil {
+		t.Fatalf("pptx: %v", err)
+	}
+}

internal/workflowdef/errors.go

@@ -11,4 +11,5 @@ var (
 	ErrPublishedImmutable = errors.New("workflowdef: published version is immutable")
 	ErrValidationFailed   = errors.New("workflowdef: validation failed")
 	ErrTemplateNotReady   = errors.New("workflowdef: template version not ready")
+	ErrUploadRejected     = errors.New("workflowdef: upload rejected")
 )

internal/workflowdef/service.go

@@ -2,12 +2,14 @@ package workflowdef
 
 import (
 	"context"
+	"fmt"
 	"path/filepath"
 	"strings"
 
 	"github.com/jackc/pgx/v5/pgxpool"
 
 	"chat-agent-system/internal/storage"
+	"chat-agent-system/internal/upload"
 )
 
 // Service 工作流定义与模板领域服务。
@@ -90,25 +92,15 @@ func (s *Service) ListTemplateVersions(ctx context.Context, assetKey string) ([]
 	return s.store.ListTemplateVersions(ctx, assetKey)
 }
 
-var allowedTemplateExt = map[string]string{
-	".md":   "text/markdown",
-	".docx": "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
-	".xlsx": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
-	".pptx": "application/vnd.openxmlformats-officedocument.presentationml.presentation",
-}
-
-// UploadTemplate 上传模板文件并创建 template_version（MVP：扩展名白名单后标记 ready）。
+// UploadTemplate 上传模板文件并创建 template_version（扩展名白名单 + MIME/魔数校验后标记 ready）。
 func (s *Service) UploadTemplate(ctx context.Context, assetKey, name string, data []byte, fileName string, createdBy int64) (*TemplateVersion, error) {
 	if !s.Available() || s.cas == nil {
 		return nil, ErrNotAvailable
 	}
 	ext := strings.ToLower(filepath.Ext(fileName))
-	mime, ok := allowedTemplateExt[ext]
-	if !ok {
-		return nil, ErrInvalidInput
-	}
-	if len(data) == 0 || len(data) > 32*1024*1024 {
-		return nil, ErrInvalidInput
+	mime, err := upload.ValidateTemplate(fileName, "", data)
+	if err != nil {
+		return nil, fmt.Errorf("%w: %v", ErrUploadRejected, err)
 	}
 
 	ref, err := s.cas.StoreFile(ctx, 0, createdBy, fileName, "template", data, mime)