asp.net MVC 自定义模型绑定 从客户端中检测到有潜在危险的 Request.QueryString 值

asp.net mvc 自定义模型绑定 有潜在的Requset.Form

自定义了一个模型绑定器。前端会传过来一些敏感字符。调用bindContext. valueProvider.GetValue(key) 则会报错 说 有潜在的从客户端中检测到有潜在危险的 Request.QueryString 值

百度谷歌都没有找到相关答案

MVC自带的默认绑定器(DefaultModelBinder)在action方法打上[ValidateInput(false)]或则在跳过验证的字段上打上[AllowHtml] 特性则可以跳过敏感字符验证

下载MVC4源码发现 他在获取的其中一个绑定方法

 public virtual object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
        {
            EnsureStackHelper.EnsureStack();
 
            if (bindingContext == null)
            {
                throw new ArgumentNullException("bindingContext");
            }
 
            bool performedFallback = false;
 
            if (!String.IsNullOrEmpty(bindingContext.ModelName) && !bindingContext.ValueProvider.ContainsPrefix(bindingContext.ModelName))
            {
                // We couldn't find any entry that began with the prefix. If this is the top-level element, fall back
                // to the empty prefix.
                if (bindingContext.FallbackToEmptyPrefix)
                {
                    bindingContext = new ModelBindingContext()
                    {
                        ModelMetadata = bindingContext.ModelMetadata,
                        ModelState = bindingContext.ModelState,
                        PropertyFilter = bindingContext.PropertyFilter,
                        ValueProvider = bindingContext.ValueProvider
                    };
                    performedFallback = true;
                }
                else
                {
                    return null;
                }
            }
 
            // Simple model = int, string, etc.; determined by calling TypeConverter.CanConvertFrom(typeof(string))
            // or by seeing if a value in the request exactly matches the name of the model we're binding.
            // Complex type = everything else.
            if (!performedFallback)
            {
                bool performRequestValidation = ShouldPerformRequestValidation(controllerContext, bindingContext);
                ValueProviderResult valueProviderResult = bindingContext.UnvalidatedValueProvider.GetValue(bindingContext.ModelName, skipValidation: !performRequestValidation);
                if (valueProviderResult != null)
                {
                    return BindSimpleModel(controllerContext, bindingContext, valueProviderResult);
                }
            }
            if (!bindingContext.ModelMetadata.IsComplexType)
            {
                return null;
            }
 
            return BindComplexModel(controllerContext, bindingContext);
        }

红色处发现他在获取参数之前获得一个bool值，

点开看看这个方法

     private static bool ShouldPerformRequestValidation(ControllerContext controllerContext, ModelBindingContext bindingContext)
        {
            if (controllerContext == null || controllerContext.Controller == null || bindingContext == null || bindingContext.ModelMetadata == null)
            {
                // To make unit testing easier, if the caller hasn't specified enough contextual information we just default
                // to always pulling the data from a collection that goes through request validation.
                return true;
            }
 
            // We should perform request validation only if both the controller and the model ask for it. This is the
            // default behavior for both. If either the controller (via [ValidateInput(false)]) or the model (via [AllowHtml])
            // opts out, we don't validate.
            return (controllerContext.Controller.ValidateRequest && bindingContext.ModelMetadata.RequestValidationEnabled);
        }

//看注释好像发现了什么 让我们通过打特性 来跳过验证

.发现他的getValue 有个重载 如果传入true则可以跳过验证

高兴的回去改自己的代码 发现bindContext.valueProvider的值提取器是接口类型System.Web.Mvc.ModelBindingContext.ValueProvider   他是没有重载方法的

看看这个东东ValueProviderResult valueProviderResult = bindingContext.UnvalidatedValueProvider.GetValue(bindingContext.ModelName, skipValidation: !performRequestValidation); 的UnvalidatedValueProvider到底是什么

       public IValueProvider ValueProvider { get; set; }
 
        internal IUnvalidatedValueProvider UnvalidatedValueProvider
        {
            get { return (ValueProvider as IUnvalidatedValueProvider) ?? new UnvalidatedValueProviderWrapper(ValueProvider); }
        }

看到这里 回头修改自己的代码吧

  //如果是基本类型 直接在值提供器中拿值绑定
                            if (property.PropertyType.IsValueType || property.PropertyType == typeof (string))
                            {
                                var newkey = property.Name;
                                if (Regex.IsMatch(key, @"\[\w*\]"))
                                {
                                    newkey = key + "[" + newkey + "]";
                                }
 
                                var value = bindingContext.ValueProvider.GetValue(newkey);
                                if (value == null)
                                {
 
                                    //再尝试获取一次
                                    var valueProvider = (bindingContext.ValueProvider as IUnvalidatedValueProvider);
                                    newkey = key + "[" + newkey + "]";
                                    value = valueProvider.GetValue(newkey,true);
                                }

当然这么做还是不严谨的 我们需要也像defualtModelBind一样 通过特性来标示是否跳过验证。而不是所有使用模型绑定的action请求都跳过验证