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SPClaimsUtility.AuthenticateFormsUser Invalid XML Error

 

Hit a strange error that Google turned up blank on.

I had a password reset page that took some encrypted parameters and used SPClaimsUtility.AuthenticateFormsUser to log the user in and set the session token.

This code

Uri appliesTo = new Uri(Page.Request.Url.AbsoluteUri);

// Set the session token
SPClaimsUtility.AuthenticateFormsUser(appliesTo,user.UserName, txtNewPassword.Text);
would fail with a an invalid XML Error

System.Xml.XmlUtf8RawTextWriter.InvalidXmlChar(Int32 ch, Byte* pDst, Boolean entitize) +2670818
   System.Xml.XmlUtf8RawTextWriter.WriteElementTextBlock(Char* pSrc, Char* pSrcEnd) +5042301
   System.Xml.XmlUtf8RawTextWriter.WriteString(String text) +85
   System.Xml.XmlWellFormedWriter.WriteValue(String value) +1959831
   System.Xml.XmlWrappedWriter.WriteValue(String value) +17
   Microsoft.SharePoint.IdentityModel.SPTokenCache.GetBytesForSessionToken(String cookieContents) +123
   Microsoft.SharePoint.IdentityModel.SPTokenCache.WriteToken(SessionSecurityToken sessionToken) +304
   Microsoft.IdentityModel.Web.SessionAuthenticationModule.WriteSessionTokenToCookie(SessionSecurityToken sessionToken) +136
   Microsoft.SharePoint.IdentityModel.SPSessionAuthenticationModule.AuthenticateSessionSecurityToken(SessionSecurityToken sessionToken, Boolean writeCookie) +40
   Microsoft.SharePoint.IdentityModel.SPFederationAuthenticationModule.SetPrincipalAndWriteSessionToken(SecurityToken securityToken, SPSessionTokenWriteType writeOperationType) +485

 

The problem happens because the SPTokenCache is writing the tokenreference claim into an custom XML format.

The tokenreference contains, among other things, the AppliesTo Url.

XML has issues with characters outside a strict range including lower or higher Ascii characters.

The mistake i made was using Page.Request.Url.AbsoluteUri which includes the parameters passed to the page,  this included lower Ascii characters as part of the encrypted string (now this could be BASE64 encoded to avoid that).

The fix is to pass in only the current Web Url

 Uri appliesTo = new Uri(SPContext.Current.Web.Url);             
 // Set the session token
SPClaimsUtility.AuthenticateFormsUser(appliesTo,user.UserName, txtNewPassword.Text);

Comments (1) -

Telecom Training

Yes! This was exactly the same problem I was having, I knew it was something like this but didn't know XML enough to quite work it out. Cheers for the post.

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