ASP.NET DefaultMembershipProvider 的哈希函数中是否存在错误？

Question

我正在迁移我的旧 ASP.NET Webforms 应用程序以开始使用 ASP.NET 内置 DefaultMembershipProvider。我的旧自制身份验证模块用于存储密码的 SHA256 哈希值。我认为“升级”到 DefaultMembershipProvider，它也在 SQL DB 中存储散列，这意味着我也可以迁移这些散列，因此为当前用户提供无痛升级（这样他们就不必重置密码）。

现在，这并没有按计划工作（显然！），我开始研究 DefaultMembershipProvider 的来源（更具体地说，就在这里：https://github.com/wyxy2005/bluceNet/tree/master/System.Web.Providers），我遇到了以下函数：

private string EncodePassword(string pass, int passwordFormat, string salt)
    {
        if (passwordFormat == 0)
        {
            return pass;
        }
        byte[] bytes = Encoding.Unicode.GetBytes(pass);
        byte[] src = Convert.FromBase64String(salt);
        byte[] inArray = null;
        if (passwordFormat == 1)
        {
            HashAlgorithm hashAlgorithm = this.GetHashAlgorithm();
            KeyedHashAlgorithm algorithm2 = hashAlgorithm as KeyedHashAlgorithm;
            if (algorithm2 != null)
            {
                if (algorithm2.Key.Length == src.Length)
                {
                    algorithm2.Key = src;
                }
                else if (algorithm2.Key.Length < src.Length)
                {
                    byte[] dst = new byte[algorithm2.Key.Length];
                    Buffer.BlockCopy(src, 0, dst, 0, dst.Length);
                    algorithm2.Key = dst;
                }
                else
                {
                    int num2;
                    byte[] buffer5 = new byte[algorithm2.Key.Length];
                    for (int i = 0; i < buffer5.Length; i += num2)
                    {
                        num2 = Math.Min(src.Length, buffer5.Length - i);
                        Buffer.BlockCopy(src, 0, buffer5, i, num2);
                    }
                    algorithm2.Key = buffer5;
                }
                inArray = algorithm2.ComputeHash(bytes);
            }
            else
            {
                byte[] buffer6 = new byte[src.Length + bytes.Length];
                Buffer.BlockCopy(src, 0, buffer6, 0, src.Length);
                Buffer.BlockCopy(bytes, 0, buffer6, src.Length, bytes.Length);
                inArray = hashAlgorithm.ComputeHash(buffer6);
            }
        }
        else
        {
            byte[] buffer7 = new byte[src.Length + bytes.Length];
            Buffer.BlockCopy(src, 0, buffer7, 0, src.Length);
            Buffer.BlockCopy(bytes, 0, buffer7, src.Length, bytes.Length);
            inArray = this.EncryptPassword(buffer7, this.LegacyPasswordCompatibilityMode);
        }
        return Convert.ToBase64String(inArray);
    }

现在，在我的特定场景中，我没有任何密码盐，因为我的旧身份验证模块没有使用它，所以 string salt 是空的，byte [] src 也是空的。默认使用的散列算法是 HMACSHA256，它是一个键控散列函数。所以我们进入了这个for循环，其中num2总是 0。由于num2也被用作增量器，我们进入了一个无限循环。

算法不应该针对这种特殊情况进行测试吗？这不应该是一个简单的错误，只需对代码进行单元测试就可以捕获吗？还是我忽略了什么？

Answer 1

我不是安全专家，因此无法回答您的问题。

这是新ASP.Net Universal Provider 使用的EncodePassword 方法。

它与旧的 MembershipProvider 有点不同。您可能想尝试一下。

private string EncodePassword(string pass, int passwordFormat, string salt)
{
    byte[] numArray;
    byte[] numArray1;
    string base64String;
    bool length = passwordFormat != 0;
    if (length)
    {
        byte[] bytes = Encoding.Unicode.GetBytes(pass);
        byte[] numArray2 = Convert.FromBase64String(salt);
        byte[] numArray3 = null;
        length = passwordFormat != 1;
        if (length)
        {
            numArray1 = new byte[(int)numArray2.Length + (int)bytes.Length];
            Buffer.BlockCopy(numArray2, 0, numArray1, 0, (int)numArray2.Length);
            Buffer.BlockCopy(bytes, 0, numArray1, (int)numArray2.Length, (int)bytes.Length);
            numArray3 = this.EncryptPassword(numArray1);
        }
        else
        {
            HashAlgorithm hashAlgorithm = this.GetHashAlgorithm();
            length = hashAlgorithm as KeyedHashAlgorithm <= null;
            if (length)
            {
                numArray1 = new byte[(int)numArray2.Length + (int)bytes.Length];
                Buffer.BlockCopy(numArray2, 0, numArray1, 0, (int)numArray2.Length);
                Buffer.BlockCopy(bytes, 0, numArray1, (int)numArray2.Length, (int)bytes.Length);
                numArray3 = hashAlgorithm.ComputeHash(numArray1);
            }
            else
            {
                KeyedHashAlgorithm keyedHashAlgorithm = (KeyedHashAlgorithm)hashAlgorithm;
                length = (int)keyedHashAlgorithm.Key.Length != (int)numArray2.Length;
                if (length)
                {
                    length = (int)keyedHashAlgorithm.Key.Length >= (int)numArray2.Length;
                    if (length)
                    {
                        numArray = new byte[(int)keyedHashAlgorithm.Key.Length];
                        int num = 0;
                        while (true)
                        {
                            length = num < (int)numArray.Length;
                            if (!length)
                            {
                                break;
                            }
                            int num1 = Math.Min((int)numArray2.Length, (int)numArray.Length - num);
                            Buffer.BlockCopy(numArray2, 0, numArray, num, num1);
                            num = num + num1;
                        }
                        keyedHashAlgorithm.Key = numArray;
                    }
                    else
                    {
                        numArray = new byte[(int)keyedHashAlgorithm.Key.Length];
                        Buffer.BlockCopy(numArray2, 0, numArray, 0, (int)numArray.Length);
                        keyedHashAlgorithm.Key = numArray;
                    }
                }
                else
                {
                    keyedHashAlgorithm.Key = numArray2;
                }
                numArray3 = keyedHashAlgorithm.ComputeHash(bytes);
            }
        }
        base64String = Convert.ToBase64String(numArray3);
    }
    else
    {
        base64String = pass;
    }
    return base64String;
}