当passwordFormat = Encrypted和decryption = AES时,从Membership迁移到Identity

Question

最近我开始开发一个新的MVC应用程序,需要使用较旧的现有asp.net成员资格数据库并将其转换为新的(呃)身份系统.

如果您发现自己处于类似的情况,那么很可能您已经从microsoft获得了这篇有用的帖子,它为您提供了很好的指导和脚本,可以将数据库转换为新架构,包括密码.

为了处理两个系统之间密码散列/加密的差异,它们包括一个自定义密码哈希,SqlPasswordHasher,它解析密码字段(已合并到Password | PasswordFormat | Salt)并尝试复制SqlMembershipProvider中的逻辑将传入的密码与存储的版本进行比较.

然而,正如我(以及该帖子上的另一位评论者)所注意到的,他们提供的这个方便的哈希不处理加密密码(尽管他们在帖子中使用的混淆语言似乎表明它确实如此).它似乎应该是,考虑到它们确实将密码格式带入数据库,但奇怪的是代码不使用它,而是

int passwordformat = 1;

这是用于散列密码.我需要的是能够使用System.Web/MachineKey配置元素的decryptionKey处理我的场景的加密密码.

如果你也处于这样的困境,并且正在使用AES算法(如machineKey的解密属性中所定义的那样),那么下面的答案应该得到解决.

Answer 1

首先,让我们快速谈谈SqlMembershipProvider在幕后做的事情.提供程序通过将两者连接在一起,将转换为byte []的salt与编码为unicode字节数组的密码组合成一个更大的字节数组.非常直截了当.然后它通过抽象(MembershipAdapter)将其传递给MachineKeySection,在那里完成实际工作.

关于该切换的重要部分是它指示MachineKeySection使用空IV(初始化向量)并且还不执行签名.那个空的IV是真正的关键,因为machineKey元素没有IV属性,所以如果你已经摸不着头脑,想知道提供者如何处理这个方面,那就是这样.一旦你知道(从挖掘源代码)然后你可以提取MachineKeySection代码中的加密代码,并将其与成员资格提供程序的代码结合起来,以获得更完整的哈希.完整来源:

public class SQLPasswordHasher : PasswordHasher
{
    public override string HashPassword(string password)
    {
        return base.HashPassword(password);
    }

    public override PasswordVerificationResult VerifyHashedPassword(string hashedPassword, string providedPassword)
    {
        string[] passwordProperties = hashedPassword.Split('|');
        if (passwordProperties.Length != 3)
        {
            return base.VerifyHashedPassword(hashedPassword, providedPassword);
        }
        else
        {
            string passwordHash = passwordProperties[0];
            int passwordformat = int.Parse(passwordProperties[1]);
            string salt = passwordProperties[2];

            if (String.Equals(EncryptPassword(providedPassword, passwordformat, salt), passwordHash, StringComparison.CurrentCultureIgnoreCase))
            {
                return PasswordVerificationResult.SuccessRehashNeeded;
            }
            else
            {
                return PasswordVerificationResult.Failed;
            }

        }
    }

    //This is copied from the existing SQL providers and is provided only for back-compat.
    private string EncryptPassword(string pass, int passwordFormat, string salt)
    {
        if (passwordFormat == 0) // MembershipPasswordFormat.Clear
            return pass;

        byte[] bIn = Encoding.Unicode.GetBytes(pass);
        byte[] bSalt = Convert.FromBase64String(salt);
        byte[] bRet = null;

        if (passwordFormat == 1)
        { // MembershipPasswordFormat.Hashed 
            HashAlgorithm hm = HashAlgorithm.Create("SHA1");
            if (hm is KeyedHashAlgorithm)
            {
                KeyedHashAlgorithm kha = (KeyedHashAlgorithm)hm;
                if (kha.Key.Length == bSalt.Length)
                {
                    kha.Key = bSalt;
                }
                else if (kha.Key.Length < bSalt.Length)
                {
                    byte[] bKey = new byte[kha.Key.Length];
                    Buffer.BlockCopy(bSalt, 0, bKey, 0, bKey.Length);
                    kha.Key = bKey;
                }
                else
                {
                    byte[] bKey = new byte[kha.Key.Length];
                    for (int iter = 0; iter < bKey.Length;)
                    {
                        int len = Math.Min(bSalt.Length, bKey.Length - iter);
                        Buffer.BlockCopy(bSalt, 0, bKey, iter, len);
                        iter += len;
                    }
                    kha.Key = bKey;
                }
                bRet = kha.ComputeHash(bIn);
            }
            else
            {
                byte[] bAll = new byte[bSalt.Length + bIn.Length];
                Buffer.BlockCopy(bSalt, 0, bAll, 0, bSalt.Length);
                Buffer.BlockCopy(bIn, 0, bAll, bSalt.Length, bIn.Length);
                bRet = hm.ComputeHash(bAll);
            }
        }
        else //MembershipPasswordFormat.Encrypted, aka 2
        {               
            byte[] bEncrypt = new byte[bSalt.Length + bIn.Length];
            Buffer.BlockCopy(bSalt, 0, bEncrypt, 0, bSalt.Length);
            Buffer.BlockCopy(bIn, 0, bEncrypt, bSalt.Length, bIn.Length);

            // Distilled from MachineKeyConfigSection EncryptOrDecryptData function, assuming AES algo and paswordCompatMode=Framework20 (the default)
            using (var stream = new MemoryStream())
            {
                var aes = new AesCryptoServiceProvider();
                aes.Key = HexStringToByteArray(MachineKey.DecryptionKey);
                aes.GenerateIV();
                aes.IV = new byte[aes.IV.Length];
                using (var transform = aes.CreateEncryptor())
                {
                    using (var stream2 = new CryptoStream(stream, transform, CryptoStreamMode.Write))
                    {
                        stream2.Write(bEncrypt, 0, bEncrypt.Length);
                        stream2.FlushFinalBlock();
                        bRet = stream.ToArray();
                    }
                }
            }               
        }

        return Convert.ToBase64String(bRet);
    }

    public static byte[] HexStringToByteArray(String hex)
    {
        int NumberChars = hex.Length;
        byte[] bytes = new byte[NumberChars / 2];
        for (int i = 0; i < NumberChars; i += 2)
            bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
        return bytes;
    }

    private static MachineKeySection MachineKey
    {
        get
        {
            //Get encryption and decryption key information from the configuration.
            System.Configuration.Configuration cfg = WebConfigurationManager.OpenWebConfiguration(System.Web.Hosting.HostingEnvironment.ApplicationVirtualPath);
            return cfg.GetSection("system.web/machineKey") as MachineKeySection;
        }
    }


}

如果您有不同的算法,那么步骤将非常接近相同,但您可能希望首先深入了解MachineKeySection的源代码,并仔细了解它们如何初始化事物.快乐的编码!