private Authorization DoAuthenticate(string challenge, WebRequest webRequest, ICredentials credentials, bool preAuthenticate)
{
if (credentials == null)
{
return(null);
}
HttpWebRequest request = webRequest as HttpWebRequest;
NTAuthentication securityContext = null;
string incomingBlob = null;
if (!preAuthenticate)
{
int index = AuthenticationManager.FindSubstringNotInQuotes(challenge, Signature);
if (index < 0)
{
return(null);
}
int startIndex = index + SignatureSize;
if ((challenge.Length > startIndex) && (challenge[startIndex] != ','))
{
startIndex++;
}
else
{
index = -1;
}
if ((index >= 0) && (challenge.Length > startIndex))
{
index = challenge.IndexOf(',', startIndex);
if (index != -1)
{
incomingBlob = challenge.Substring(startIndex, index - startIndex);
}
else
{
incomingBlob = challenge.Substring(startIndex);
}
}
securityContext = request.CurrentAuthenticationState.GetSecurityContext(this);
}
if (securityContext == null)
{
NetworkCredential credential = credentials.GetCredential(request.ChallengedUri, Signature);
if ((credential == null) || (!(credential is SystemNetworkCredential) && (credential.InternalGetUserName().Length == 0)))
{
return(null);
}
ICredentialPolicy credentialPolicy = AuthenticationManager.CredentialPolicy;
if ((credentialPolicy != null) && !credentialPolicy.ShouldSendCredential(request.ChallengedUri, request, credential, this))
{
return(null);
}
string computeSpn = request.CurrentAuthenticationState.GetComputeSpn(request);
ChannelBinding channelBinding = null;
if (request.CurrentAuthenticationState.TransportContext != null)
{
channelBinding = request.CurrentAuthenticationState.TransportContext.GetChannelBinding(ChannelBindingKind.Endpoint);
}
securityContext = new NTAuthentication("Kerberos", credential, computeSpn, request, channelBinding);
request.CurrentAuthenticationState.SetSecurityContext(securityContext, this);
}
string outgoingBlob = securityContext.GetOutgoingBlob(incomingBlob);
if (outgoingBlob == null)
{
return(null);
}
return(new Authorization("Kerberos " + outgoingBlob, securityContext.IsCompleted, string.Empty, securityContext.IsMutualAuthFlag));
}
