update: chunk upload

handlers.go

@@ -24,6 +24,12 @@ type fileResponse struct {
 	ExpiresAt  time.Time `json:"expires_at"`
 }
 
+// checkFilenameSafe 校验文件名: 不含 NUL 字节, 且不超过 200 字节 (Linux NAME_MAX=255 的余量).
+// 供 uploadHandler 与 uploadChunkHandler 复用 (NUL/200 校验只写这一份).
+func checkFilenameSafe(name string) bool {
+	return !strings.ContainsRune(name, 0) && len(name) <= 200
+}
+
 // validateFilename 从 URL/JSON 参数提取并校验 filename.
 // 返回 (sanitized, true) 表示安全可访问, 否则返回 ("", false).
 // 规则与 downloadHandler 原内联逻辑一致: filepath.Base + 拒绝 "" / "." / ".."
@@ -44,14 +50,14 @@ func uploadHandler(c *gin.Context) {
 		audit(c, "upload", gin.H{"file": "", "result": "missing_form_field"})
 		return
 	}
-	// 早 reject: 防止 NUL 字节 + 超长文件名打爆 Stat/Save
-	if strings.ContainsRune(f.Filename, 0) {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "filename contains null byte"})
-		audit(c, "upload", gin.H{"file": f.Filename, "result": "null_byte"})
-		return
-	}
-	// Linux/macOS 路径分量 NAME_MAX = 255 字节
-	if len(f.Filename) > 200 {
+	// 早 reject: 防止 NUL 字节 + 超长文件名打爆 Stat/Save (规则与分片上传共用)
+	if !checkFilenameSafe(f.Filename) {
+		if strings.ContainsRune(f.Filename, 0) {
+			c.JSON(http.StatusBadRequest, gin.H{"error": "filename contains null byte"})
+			audit(c, "upload", gin.H{"file": f.Filename, "result": "null_byte"})
+			return
+		}
+		// Linux/macOS 路径分量 NAME_MAX = 255 字节
 		c.JSON(http.StatusBadRequest, gin.H{"error": "filename too long (max 200 bytes)"})
 		audit(c, "upload", gin.H{"file": f.Filename, "result": "filename_too_long"})
 		return