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//------------------------------------------------------------------------------
// <copyright file="_NegotiateClient.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Net {
using System.Security.Authentication.ExtendedProtection;
internal class NegotiateClient : ISessionAuthenticationModule {
internal const string AuthType = "Negotiate";
private const string negotiateHeader = "Negotiate";
private const string negotiateSignature = "negotiate";
private const string nego2Header = "Nego2";
private const string nego2Signature = "nego2";
public Authorization Authenticate(string challenge, WebRequest webRequest, ICredentials credentials) {
GlobalLog.Print("NegotiateClient::Authenticate() challenge:[" + ValidationHelper.ToString(challenge) + "] webRequest#" + ValidationHelper.HashString(webRequest) + " credentials#" + ValidationHelper.HashString(credentials) + " calling DoAuthenticate()");
return DoAuthenticate(challenge, webRequest, credentials, false);
}
private Authorization DoAuthenticate(string challenge, WebRequest webRequest, ICredentials credentials, bool preAuthenticate) {
GlobalLog.Print("NegotiateClient::DoAuthenticate() challenge:[" + ValidationHelper.ToString(challenge) + "] webRequest#" + ValidationHelper.HashString(webRequest) + " credentials#" + ValidationHelper.HashString(credentials) + " preAuthenticate:" + preAuthenticate.ToString());
GlobalLog.Assert(credentials != null, "NegotiateClient::DoAuthenticate()|credentials == null");
if (credentials == null) {
return null;
}
HttpWebRequest httpWebRequest = webRequest as HttpWebRequest;
GlobalLog.Assert(httpWebRequest != null, "NegotiateClient::DoAuthenticate()|httpWebRequest == null");
GlobalLog.Assert(httpWebRequest.ChallengedUri != null, "NegotiateClient::DoAuthenticate()|httpWebRequest.ChallengedUri == null");
NTAuthentication authSession = null;
string incoming = null;
bool useNego2 = false; // In case of pre-auth we always use "Negotiate", never "Nego2".
if (!preAuthenticate) {
int index = GetSignatureIndex(challenge, out useNego2);
if (index < 0) {
return null;
}
int blobBegin = index + (useNego2 ? nego2Signature.Length : negotiateSignature.Length);
//
// there may be multiple challenges. If the next character after the
// package name is not a comma then it is challenge data
//
if (challenge.Length > blobBegin && challenge[blobBegin] != ',') {
++blobBegin;
}
else {
index = -1;
}
if (index >= 0 && challenge.Length > blobBegin)
{
// Strip other modules information in case of multiple challenges
// i.e do not take ", NTLM" as part of the following Negotiate blob
// Negotiate TlRMTVNTUAACAAAADgAOADgAAAA1wo ... MAbwBmAHQALgBjAG8AbQAAAAAA,NTLM
index = challenge.IndexOf(',', blobBegin);
if (index != -1)
incoming = challenge.Substring(blobBegin, index - blobBegin);
else
incoming = challenge.Substring(blobBegin);
}
authSession = httpWebRequest.CurrentAuthenticationState.GetSecurityContext(this);
GlobalLog.Print("NegotiateClient::DoAuthenticate() key:" + ValidationHelper.HashString(httpWebRequest.CurrentAuthenticationState) + " retrieved authSession:" + ValidationHelper.HashString(authSession));
}
if (authSession==null)
{
// Credentials are always set for "Negotiate", never for "Nego2". A customer shouldn't even know
// about "Nego2".
NetworkCredential NC = credentials.GetCredential(httpWebRequest.ChallengedUri, negotiateSignature);
GlobalLog.Print("NegotiateClient::DoAuthenticate() GetCredential() returns:" + ValidationHelper.ToString(NC));
string username = string.Empty;
if (NC == null || (!(NC is SystemNetworkCredential) && (username = NC.InternalGetUserName()).Length == 0))
{
return null;
}
ICredentialPolicy policy = AuthenticationManager.CredentialPolicy;
if (policy != null && !policy.ShouldSendCredential(httpWebRequest.ChallengedUri, httpWebRequest, NC, this))
return null;
SpnToken spn = httpWebRequest.CurrentAuthenticationState.GetComputeSpn(httpWebRequest);
GlobalLog.Print("NegotiateClient::Authenticate() ChallengedSpn:" + ValidationHelper.ToString(spn));
ChannelBinding binding = null;
if (httpWebRequest.CurrentAuthenticationState.TransportContext != null)
{
binding = httpWebRequest.CurrentAuthenticationState.TransportContext.GetChannelBinding(ChannelBindingKind.Endpoint);
}
authSession =
new NTAuthentication(
AuthType,
NC,
spn,
httpWebRequest,
binding);
GlobalLog.Print("NegotiateClient::DoAuthenticate() setting SecurityContext for:" + ValidationHelper.HashString(httpWebRequest.CurrentAuthenticationState) + " to authSession:" + ValidationHelper.HashString(authSession));
httpWebRequest.CurrentAuthenticationState.SetSecurityContext(authSession, this);
}
string clientResponse = authSession.GetOutgoingBlob(incoming);
if (clientResponse==null) {
return null;
}
bool canShareConnection = httpWebRequest.UnsafeOrProxyAuthenticatedConnectionSharing;
if (canShareConnection) {
httpWebRequest.LockConnection = true;
}
// this is the first leg of an NTLM handshake,
// set the NtlmKeepAlive override *STRICTLY* only in this case.
httpWebRequest.NtlmKeepAlive = incoming==null && authSession.IsValidContext && !authSession.IsKerberos;
// If we received a "Nego2" header value from the server, we'll respond with "Nego2" in the "Authorization"
// header. If the server sent a "Negotiate" header value or if pre-authenticate is used (i.e. the auth blob
// is sent with the first request), we send "Negotiate" in the "Authorization" header.
return AuthenticationManager.GetGroupAuthorization(this, (useNego2 ? nego2Header : negotiateHeader) +
" " + clientResponse, authSession.IsCompleted, authSession, canShareConnection, authSession.IsKerberos);
}
public bool CanPreAuthenticate {
get {
return true;
}
}
public Authorization PreAuthenticate(WebRequest webRequest, ICredentials credentials) {
GlobalLog.Print("NegotiateClient::PreAuthenticate() webRequest#" + ValidationHelper.HashString(webRequest) + " credentials#" + ValidationHelper.HashString(credentials) + " calling DoAuthenticate()");
return DoAuthenticate(null, webRequest, credentials, true);
}
public string AuthenticationType {
get {
return AuthType;
}
}
//
// called when getting the final blob on the 200 OK from the server
//
public bool Update(string challenge, WebRequest webRequest) {
GlobalLog.Print("NegotiateClient::Update(): " + challenge);
HttpWebRequest httpWebRequest = webRequest as HttpWebRequest;
GlobalLog.Assert(httpWebRequest != null, "NegotiateClient::Update()|httpWebRequest == null");
GlobalLog.Assert(httpWebRequest.ChallengedUri != null, "NegotiateClient::Update()|httpWebRequest.ChallengedUri == null");
//
// try to retrieve the state of the ongoing handshake
//
NTAuthentication authSession = httpWebRequest.CurrentAuthenticationState.GetSecurityContext(this);
GlobalLog.Print("NegotiateClient::Update() key:" + ValidationHelper.HashString(httpWebRequest.CurrentAuthenticationState) + " retrieved authSession:" + ValidationHelper.HashString(authSession));
if (authSession==null) {
GlobalLog.Print("NegotiateClient::Update() null session returning true");
return true;
}
GlobalLog.Print("NegotiateClient::Update() authSession.IsCompleted:" + authSession.IsCompleted.ToString());
if (!authSession.IsCompleted && httpWebRequest.CurrentAuthenticationState.StatusCodeMatch==httpWebRequest.ResponseStatusCode) {
GlobalLog.Print("NegotiateClient::Update() still handshaking (based on status code) returning false");
return false;
}
// now possibly close the ConnectionGroup after authentication is done.
if (!httpWebRequest.UnsafeOrProxyAuthenticatedConnectionSharing) {
GlobalLog.Print("NegotiateClient::Update() releasing ConnectionGroup:" + httpWebRequest.GetConnectionGroupLine());
httpWebRequest.ServicePoint.ReleaseConnectionGroup(httpWebRequest.GetConnectionGroupLine());
}
//
// the whole point here is to close the Security Context (this will complete the authentication handshake
// with server authentication for schemese that support it such as Kerberos)
//
bool useNego2 = true;
int index = challenge==null ? -1 : GetSignatureIndex(challenge, out useNego2);
if (index>=0) {
int blobBegin = index + (useNego2 ? nego2Signature.Length : negotiateSignature.Length);
string incoming = null;
//
// there may be multiple challenges. If the next character after the
// package name is not a comma then it is challenge data
//
if (challenge.Length > blobBegin && challenge[blobBegin] != ',') {
++blobBegin;
} else {
index = -1;
}
if (index >= 0 && challenge.Length > blobBegin) {
incoming = challenge.Substring(blobBegin);
}
GlobalLog.Print("NegotiateClient::Update() this must be a final incoming blob:[" + ValidationHelper.ToString(incoming) + "]");
string clientResponse = authSession.GetOutgoingBlob(incoming);
httpWebRequest.CurrentAuthenticationState.Authorization.MutuallyAuthenticated = authSession.IsMutualAuthFlag;
GlobalLog.Print("NegotiateClient::Update() GetOutgoingBlob() returns clientResponse:[" + ValidationHelper.ToString(clientResponse) + "] IsCompleted:" + authSession.IsCompleted.ToString());
}
// Extract the CBT we used and cache it for future requests that want to do preauth
httpWebRequest.ServicePoint.SetCachedChannelBinding(httpWebRequest.ChallengedUri, authSession.ChannelBinding);
GlobalLog.Print("NegotiateClient::Update() session removed and ConnectionGroup released returning true");
ClearSession(httpWebRequest);
return true;
}
public void ClearSession(WebRequest webRequest) {
HttpWebRequest httpWebRequest = webRequest as HttpWebRequest;
GlobalLog.Assert(httpWebRequest != null, "NegotiateClient::ClearSession()|httpWebRequest == null");
httpWebRequest.CurrentAuthenticationState.ClearSession();
}
public bool CanUseDefaultCredentials {
get {
return true;
}
}
private static int GetSignatureIndex(string challenge, out bool useNego2) {
// Negotiate supports two header fields "Nego2" and "Negotiate". If we find "Nego2" we use it,
// otherwise we fall back to "Negotiate" (if available).
useNego2 = true;
int index = -1;
// Consider Nego2 headers only on Win7 and later. Older OS version don't support LiveSSP.
if (ComNetOS.IsWin7orLater) {
index = AuthenticationManager.FindSubstringNotInQuotes(challenge, nego2Signature);
}
if (index < 0) {
useNego2 = false;
index = AuthenticationManager.FindSubstringNotInQuotes(challenge, negotiateSignature);
}
return index;
}
}; // class NegotiateClient
} // namespace System.Net
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