ASP.NET核心JWT承载令牌自定义验证

Question

经过大量阅读，我找到了一种实现自定义JWT承载令牌验证器的方法，如下所示。

Starup.cs代码：

public void Configure(IApplicationBuilder app, IHostingEnvironment env, 
         ILoggerFactory loggerFactory, IApplicationLifetime appLifetime)
{
    loggerFactory.AddConsole(Configuration.GetSection("Logging"));
    loggerFactory.AddDebug();

    app.UseStaticFiles();

    app.UseIdentity();

    ConfigureAuth(app);

    app.UseMvcWithDefaultRoute();            
}

private void ConfigureAuth(IApplicationBuilder app)
    {

        var signingKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(Configuration.GetSection("TokenAuthentication:SecretKey").Value));


        var tokenValidationParameters = new TokenValidationParameters
        {
            // The signing key must match!
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = signingKey,
            // Validate the JWT Issuer (iss) claim
            ValidateIssuer = true,
            ValidIssuer = Configuration.GetSection("TokenAuthentication:Issuer").Value,
            // Validate the JWT Audience (aud) claim
            ValidateAudience = true,
            ValidAudience = Configuration.GetSection("TokenAuthentication:Audience").Value,
            // Validate the token expiry
            ValidateLifetime = true,
            // If you want to allow a certain amount of clock drift, set that here:
            ClockSkew = TimeSpan.Zero
        };

        var jwtBearerOptions = new JwtBearerOptions();
        jwtBearerOptions.AutomaticAuthenticate = true;
        jwtBearerOptions.AutomaticChallenge = true;
        jwtBearerOptions.TokenValidationParameters = tokenValidationParameters;
        jwtBearerOptions.SecurityTokenValidators.Clear();
        //below line adds the custom validator class
        jwtBearerOptions.SecurityTokenValidators.Add(new CustomJwtSecurityTokenHandler());
        app.UseJwtBearerAuthentication(jwtBearerOptions);

        var tokenProviderOptions = new TokenProviderOptions
        {
            Path = Configuration.GetSection("TokenAuthentication:TokenPath").Value,
            Audience = Configuration.GetSection("TokenAuthentication:Audience").Value,
            Issuer = Configuration.GetSection("TokenAuthentication:Issuer").Value,
            SigningCredentials = new SigningCredentials(signingKey, SecurityAlgorithms.HmacSha256)
        };

        app.UseMiddleware<TokenProviderMiddleware>(Options.Create(tokenProviderOptions));
    }

以下是自定义验证器类：

public class CustomJwtSecurityTokenHandler : ISecurityTokenValidator
{
    private int _maxTokenSizeInBytes = TokenValidationParameters.DefaultMaximumTokenSizeInBytes;
    private JwtSecurityTokenHandler _tokenHandler;

    public CustomJwtSecurityTokenHandler()
    {
        _tokenHandler = new JwtSecurityTokenHandler();
    }

    public bool CanValidateToken
    {
        get
        {
            return true;
        }
    }

    public int MaximumTokenSizeInBytes
    {
        get
        {
            return _maxTokenSizeInBytes;
        }

        set
        {
            _maxTokenSizeInBytes = value;
        }
    }

    public bool CanReadToken(string securityToken)
    {
        return _tokenHandler.CanReadToken(securityToken);            
    }

    public ClaimsPrincipal ValidateToken(string securityToken, TokenValidationParameters validationParameters, out SecurityToken validatedToken)
    {
        //How to access HttpContext/IP address from here?

        var principal = _tokenHandler.ValidateToken(securityToken, validationParameters, out validatedToken);

        return principal;
    }
}

如果被盗令牌，我想添加一层额外的安全性来验证请求是否来自生成令牌的同一客户端。

问题：

1. 有什么方法可以访问HttpContext类中的CustomJwtSecurityTokenHandler，以便我可以根据当前客户端/请求者添加自定义验证吗？
2. 有没有其他方法可以使用这样的方法/中间件验证请求者的真实性？

Answer 1

在ASP.NET Core中，HttpContext可以使用IHttpContextAccessor服务获得。使用DI将IHttpContextAccessor实例传递给您的处理程序并获取IHttpContextAccessor.HttpContext属性的值。

IHttpContextAccessor服务未由defaul注册，因此您首先需要在Startup.ConfigureServices方法中添加以下内容：

services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();

然后修改你的CustomJwtSecurityTokenHandler类：

private readonly IHttpContextAccessor _httpContextAccessor;

public CustomJwtSecurityTokenHandler(IHttpContextAccessor httpContextAccessor)
{
    _httpContextAccessor = httpContextAccessor;
    _tokenHandler = new JwtSecurityTokenHandler();
}

... 

public ClaimsPrincipal ValidateToken(string securityToken, TokenValidationParameters validationParameters, out SecurityToken validatedToken)
{
    var httpContext = _httpContextAccessor.HttpContext;
}

---

您还应该使用DI技术进行JwtSecurityTokenHandler实例化。如果您对所有这些东西都不熟悉，请查看Dependency Injection文档。

---

更新：如何手动解决依赖关系（更多信息here）

修改Configure方法使用IServiceProvider serviceProvider：

public void Configure(IApplicationBuilder app, IHostingEnvironment env, 
         ILoggerFactory loggerFactory, IApplicationLifetime appLifetime,
         IServiceProvider serviceProvider)
{
    ...
    var httpContextAccessor = serviceProvider.GetService<IHttpContextAccessor>();
    // and extend ConfigureAuth
    ConfigureAuth(app, httpContextAccessor);
    ...
}

Answer 2

对于自定义JWT验证器，我在IOAuthBearerAuthenticationProvider中创建了一个JWTCosumerProvider类。并实现ValidateIdentity（）方法来检查我在第一时间存储客户端IP地址的身份声明，然后与之后的当前请求ID地址进行比较。

public Task ValidateIdentity(OAuthValidateIdentityContext context)
    {

        var requestIPAddress = context.Ticket.Identity.FindFirst(ClaimTypes.Dns)?.Value;

        if (requestIPAddress == null)
            context.SetError("Token Invalid", "The IP Address not right");

        string clientAddress = JWTHelper.GetClientIPAddress();
        if (!requestIPAddress.Equals(clientAddress))
            context.SetError("Token Invalid", "The IP Address not right");


        return Task.FromResult<object>(null);
    }

JWTHelper.GetClientIPAddress（）

internal static string GetClientIPAddress()
    {
        System.Web.HttpContext context = System.Web.HttpContext.Current;
        string ipAddress = context.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

        if (!string.IsNullOrEmpty(ipAddress))
        {
            string[] addresses = ipAddress.Split(',');
            if (addresses.Length != 0)
            {
                return addresses[0];
            }
        }

        return context.Request.ServerVariables["REMOTE_ADDR"];
    }

希望这个帮助！