SSO SAML的已签名XML签名验证(使用sha256)

本文关键字：签名验证 使用 sha256 XML SAML SSO | 更新日期: 2023-09-27 18:15:12

在windows 2003服务器上使用VS 2008和。net Framework 3.5。

为了安全性，我们已经使用SAML实现了SSO。我们在服务提供者端工作，验证从客户端系统生成的Signed XML SAML Assertuib令牌。到目前为止，我们遇到的任何签名文件都是使用签名算法"rsa-sha1"，但现在我们有了一个新客户，他发送了一个签名算法为"rsa-sha256"的文件，问题开始了。

public static string VerifySignature()
{
    if (m_xmlDoc == null)
        return "Could not load XMLDocument ";
    try
    {
        XmlNamespaceManager nsm = new XmlNamespaceManager(new NameTable());
        nsm.AddNamespace("dsig", SignedXml.XmlDsigNamespaceUrl);
        XmlElement sigElt = (XmlElement)m_xmlDoc.SelectSingleNode(
            "//dsig:Signature", nsm);
        // Load the signature for verification
        SignedXml sig = new SignedXml(m_xmlDoc);
        sig.LoadXml(sigElt);
        if (!sig.CheckSignature())
            return "Invalid Signature";
    }
    catch (Exception ex)
    {
        return ex.Message;
    }
    return string.Empty;
}

现在，当我为这个新客户(使用签名算法rsa-sha256h)尝试相同的代码时-这不起作用，并且我得到错误"无法为提供的签名算法创建SignatureDescription"。

在过去的2-3天里，通过阅读许多博客和文章，我知道SignedXml不支持sha256。很好。但接下来呢?有些地方提到使用WIF，我也检查了&尝试这个。

我也在尝试使用RSAPKCS1SignatureDeformatter的verifsignsignature方法。但是不确定要传递的两个参数是什么

SSO SAML的已签名XML签名验证(使用sha256)

Dotnet 4.6.2+内置了较新的sha哈希值。对于dotnet 4 +，要访问rsa-sha512、rsa-sha384和rsa-sha256，您应该在某处包含此代码。

/// <summary>Declare the signature type for rsa-sha512</summary>
public class RsaPkCs1Sha512SignatureDescription : SignatureDescription
{
    public RsaPkCs1Sha512SignatureDescription()
    {
        KeyAlgorithm = typeof(RSACryptoServiceProvider).FullName;
        DigestAlgorithm = typeof(SHA512CryptoServiceProvider).FullName;
        FormatterAlgorithm = typeof(RSAPKCS1SignatureFormatter).FullName;
        DeformatterAlgorithm = typeof(RSAPKCS1SignatureDeformatter).FullName;
    }
    public override AsymmetricSignatureDeformatter CreateDeformatter(AsymmetricAlgorithm key)
    {
        var sigProcessor = (AsymmetricSignatureDeformatter)CryptoConfig.CreateFromName(DeformatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA512");
        return sigProcessor;
    }
    public override AsymmetricSignatureFormatter CreateFormatter(AsymmetricAlgorithm key)
    {
        var sigProcessor =
            (AsymmetricSignatureFormatter)CryptoConfig.CreateFromName(FormatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA512");
        return sigProcessor;
    }
}
/// <summary>Declare the signature type for rsa-sha384</summary>
public class RsaPkCs1Sha384SignatureDescription : SignatureDescription {
    public RsaPkCs1Sha384SignatureDescription()
    {
        KeyAlgorithm = typeof(RSACryptoServiceProvider).FullName;
        DigestAlgorithm = typeof(SHA384CryptoServiceProvider).FullName;
        FormatterAlgorithm = typeof(RSAPKCS1SignatureFormatter).FullName;
        DeformatterAlgorithm = typeof(RSAPKCS1SignatureDeformatter).FullName;
    }
    public override AsymmetricSignatureDeformatter CreateDeformatter(AsymmetricAlgorithm key)
    {
        var sigProcessor = (AsymmetricSignatureDeformatter) CryptoConfig.CreateFromName(DeformatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA384");
        return sigProcessor;
    }
    public override AsymmetricSignatureFormatter CreateFormatter(AsymmetricAlgorithm key)
    {
        var sigProcessor =
            (AsymmetricSignatureFormatter)CryptoConfig.CreateFromName(FormatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA384");
        return sigProcessor;
    }
}
/// <summary>Declare the signature type for rsa-sha256</summary>
public class RsaPkCs1Sha256SignatureDescription : SignatureDescription
{
    public RsaPkCs1Sha256SignatureDescription()
    {
        KeyAlgorithm = typeof(RSACryptoServiceProvider).FullName;
        DigestAlgorithm = typeof(SHA256CryptoServiceProvider).FullName;
        FormatterAlgorithm = typeof(RSAPKCS1SignatureFormatter).FullName;
        DeformatterAlgorithm = typeof(RSAPKCS1SignatureDeformatter).FullName;
    }
    public override AsymmetricSignatureDeformatter CreateDeformatter(AsymmetricAlgorithm key)
    {
        var sigProcessor =
            (AsymmetricSignatureDeformatter) CryptoConfig.CreateFromName(DeformatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA256");
        return sigProcessor;
    }
    public override AsymmetricSignatureFormatter CreateFormatter(AsymmetricAlgorithm key)
    {
        var sigProcessor =
            (AsymmetricSignatureFormatter)CryptoConfig.CreateFromName(FormatterAlgorithm);
        sigProcessor.SetKey(key);
        sigProcessor.SetHashAlgorithm("SHA256");
        return sigProcessor;
    }
}

然后，您应该通过调用这样的代码来激活这些信号描述。你只需要调用它一次，所以如果你愿意，你可以从静态构造函数调用它。

    CryptoConfig.AddAlgorithm(typeof(RsaPkCs1Sha512SignatureDescription),
        "http://www.w3.org/2001/04/xmldsig-more#rsa-sha512");
    CryptoConfig.AddAlgorithm(typeof(RsaPkCs1Sha384SignatureDescription),
        "http://www.w3.org/2001/04/xmldsig-more#rsa-sha384");
    CryptoConfig.AddAlgorithm(typeof(RsaPkCs1Sha256SignatureDescription),
        "http://www.w3.org/2001/04/xmldsig-more#rsa-sha256");

向微软的Carlos Lopez、BitSchupster和Andrew致敬。

对于。net 4及更早版本，我发现添加Security后，下面的工作就可以了。密码从http://clrsecurity.codeplex.com/

(注意X509CertificateFinder是我自己的，通过拇指指纹在证书存储中查找签名证书)

        /// <summary>
        /// Validate an XmlDocuments signature
        /// </summary>
        /// <param name="xnlDoc"> The saml response with the signature elemenet to validate </param>
        /// <returns> True if signature can be validated with certificate </returns>
        public bool ValidateX509CertificateSignature(XmlDocument xnlDoc)
        {
            XmlNodeList XMLSignatures = xnlDoc.GetElementsByTagName("Signature", "http://www.w3.org/2000/09/xmldsig#");
            // Checking If the Response or the Assertion has been signed once and only once.
            if (XMLSignatures.Count != 1) return false;
            var signedXmlDoc = new SignedXml(xnlDoc);
            signedXmlDoc.LoadXml((XmlElement)XMLSignatures[0]);
            var certFinder = new X509CertificateFinder();
            var foundCert = certFinder.GetSignatureCertificate();
            CryptoConfig.AddAlgorithm(typeof(RSAPKCS1SHA256SignatureDescription), "http://www.w3.org/2001/04/xmldsig-more#rsa-sha256");
            return signedXmlDoc.CheckSignature(foundCert,false);
        }

这符合"简单"，但可能不是"解决方案":)对于我们遇到的少数客户，我们已经要求他们将IdP更改为使用SHA-1签名。他们能够改变它，当他们这样做时，它就会起作用。

不是一个技术上的解决方案，但它已经在"现场"工作，所以我想我应该提一下。

只需更新到。net框架4.6.01590或更高版本，它将支持SHA-512而无需任何代码更改

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