Kerberos SPN generation for Negotiate challenges

net/http/http_auth_handler_negotiate_win.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/http/http_auth_handler_negotiate.h"
 
 #include "base/logging.h"
+#include "net/base/address_family.h"
+#include "net/base/host_resolver.h"
 #include "net/base/net_errors.h"
 #include "net/http/http_auth_filter.h"
 
 namespace net {
 
 HttpAuthHandlerNegotiate::HttpAuthHandlerNegotiate(SSPILibrary* library,
-                                                   ULONG max_token_length)
-    : auth_sspi_(library, "Negotiate", NEGOSSP_NAME, max_token_length) {
+                                                   ULONG max_token_length,
+                                                   bool disable_cname_lookup,
+                                                   bool use_port)
+    : auth_sspi_(library, "Negotiate", NEGOSSP_NAME, max_token_length),
+      user_callback_(NULL),
+      ALLOW_THIS_IN_INITIALIZER_LIST(resolve_cname_callback_(
+          this, &HttpAuthHandlerNegotiate::OnResolveCanonicalName)),
+      disable_cname_lookup_(disable_cname_lookup),
+      use_port_(use_port) {
 }
 
 HttpAuthHandlerNegotiate::~HttpAuthHandlerNegotiate() {
 }
 
 int HttpAuthHandlerNegotiate::GenerateAuthToken(
     const std::wstring& username,
     const std::wstring& password,
     const HttpRequestInfo* request,
     const ProxyInfo* proxy,
     std::string* auth_token) {
   return auth_sspi_.GenerateAuthToken(
       &username,
       &password,
-      origin_,
+      spn_,
       request,
       proxy,
       auth_token);
 }
 
 // The Negotiate challenge header looks like:
 //   WWW-Authenticate: NEGOTIATE auth-data
 bool HttpAuthHandlerNegotiate::Init(HttpAuth::ChallengeTokenizer* challenge) {
   scheme_ = "negotiate";
   score_ = 4;
   properties_ = ENCRYPTS_IDENTITY | IS_CONNECTION_BASED;
   return auth_sspi_.ParseChallenge(challenge);
 }
 
 // Require identity on first pass instead of second.
 bool HttpAuthHandlerNegotiate::NeedsIdentity() {
   return auth_sspi_.NeedsIdentity();
 }
 
 bool HttpAuthHandlerNegotiate::IsFinalRound() {
   return auth_sspi_.IsFinalRound();
 }
 
 bool HttpAuthHandlerNegotiate::SupportsDefaultCredentials() {
   return true;
 }
 
+bool HttpAuthHandlerNegotiate::NeedsCanonicalName() {
+  if (!spn_.empty())
+    return false;
+  if (disable_cname_lookup_) {
+    spn_ = CreateSPN(address_list_, origin_);
+    address_list_.Reset();
+    return false;
+  }
+  return true;
+}
+
+int HttpAuthHandlerNegotiate::ResolveCanonicalName(HostResolver* resolver,
+                                                   CompletionCallback* callback,
+                                                   const BoundNetLog& net_log) {
+  // TODO(cbentzel): Add reverse DNS lookup for numeric addresses.
+  DCHECK(!single_resolve_.get());
+  DCHECK(!disable_cname_lookup_);
+  DCHECK(callback);
+
+  HostResolver::RequestInfo info(origin_.host(), 0);
+  info.set_host_resolver_flags(HOST_RESOLVER_CANONNAME);
+  single_resolve_.reset(new SingleRequestHostResolver(resolver));
+  int rv = single_resolve_->Resolve(info, &address_list_,
+                                    &resolve_cname_callback_,
+                                    net_log);
+  if (rv == ERR_IO_PENDING) {
+    user_callback_ = callback;
+    return rv;
+  }
+  OnResolveCanonicalName(rv);
+  // Always return OK. OnResolveCanonicalName logs the error code if not
+  // OK and attempts to use the original origin_ hostname rather than failing
+  // the auth attempt completely.
+  return OK;
+}
+
+void HttpAuthHandlerNegotiate::OnResolveCanonicalName(int result) {
+  if (result != OK) {
+    // Even in the error case, try to use origin_.host instead of
+    // passing the failure on to the caller.
+    LOG(INFO) << "Problem finding canonical name for SPN for host "
+              << origin_.host() << ": " << ErrorToString(result);
+    result = OK;
+  }
+  spn_ = CreateSPN(address_list_, origin_);
+  address_list_.Reset();
+  if (user_callback_) {
+    CompletionCallback* callback = user_callback_;
+    user_callback_ = NULL;
+    callback->Run(result);
+  }
+}
+
+std::wstring HttpAuthHandlerNegotiate::CreateSPN(
+    const AddressList& address_list, const GURL& origin) {
+  // Kerberos SPNs are in the form HTTP/<host>:<port>
+  //   http://msdn.microsoft.com/en-us/library/ms677601%28VS.85%29.aspx
+  //
+  // However, reality differs from the specification. A good description of
+  // the problems can be found here:
+  //   http://blog.michelbarneveld.nl/michel/archive/2009/11/14/the-reason-why-kb911149-and-kb908209-are-not-the-soluton.aspx
+  //
+  // Typically the <host> portion should be the canonical FQDN for the service.
+  // If this could not be resolved, the original hostname in the URL will be
+  // attempted instead. However, some intranets register SPNs using aliases
+  // for the same canonical DNS name to allow multiple web services to reside
+  // on the same host machine without requiring different ports. IE6 and IE7
+  // have hotpatches that allow the default behavior to be overridden.
+  //   http://support.microsoft.com/kb/911149
+  //   http://support.microsoft.com/kb/938305
+  //
+  // According to the spec, the <port> option should be included if it is a
+  // non-standard port (i.e. not 80 or 443 in the HTTP case). However,
+  // historically browsers have not included the port, even on non-standard
+  // ports. IE6 required a hotpatch and a registry setting to enable
+  // including non-standard ports, and IE7 and IE8 also require the same
+  // registry setting, but no hotpatch. Firefox does not appear to have an
+  // option to include non-standard ports as of 3.6.
+  //   http://support.microsoft.com/kb/908209
+  //
+  // Without any command-line flags, Chrome matches the behavior of Firefox
+  // and IE. Users can override the behavior so aliases are allowed and
+  // non-standard ports are included.
+  int port = origin.EffectiveIntPort();
+  std::string server;
+  if (!address_list.GetCanonicalName(&server))
+    server = origin.host();
+  if (port != 80 && port != 443 && use_port_) {
+    return ASCIIToWide(StringPrintf("HTTP/%s:%d", server.c_str(), port));
+  } else {
+    return ASCIIToWide(StringPrintf("HTTP/%s", server.c_str()));
+  }
+}
+
 int HttpAuthHandlerNegotiate::GenerateDefaultAuthToken(
     const HttpRequestInfo* request,
     const ProxyInfo* proxy,
     std::string* auth_token) {
   return auth_sspi_.GenerateAuthToken(
       NULL,  // username
       NULL,  // password
-      origin_,
+      spn_,
       request,
       proxy,
       auth_token);
 }
 
 HttpAuthHandlerNegotiate::Factory::Factory()
-    : max_token_length_(0),
+    : disable_cname_lookup_(false),
+      use_port_(false),
+      max_token_length_(0),
       first_creation_(true),
       is_unsupported_(false),
       sspi_library_(SSPILibrary::GetDefault()) {
 }
 
 HttpAuthHandlerNegotiate::Factory::~Factory() {
 }
 
 int HttpAuthHandlerNegotiate::Factory::CreateAuthHandler(
     HttpAuth::ChallengeTokenizer* challenge,
     HttpAuth::Target target,
     const GURL& origin,
     scoped_refptr<HttpAuthHandler>* handler) {
   if (is_unsupported_)
     return ERR_UNSUPPORTED_AUTH_SCHEME;
   if (max_token_length_ == 0) {
     int rv = DetermineMaxTokenLength(sspi_library_, NEGOSSP_NAME,
                                      &max_token_length_);
     if (rv == ERR_UNSUPPORTED_AUTH_SCHEME)
       is_unsupported_ = true;
     if (rv != OK)
       return rv;
   }
   // TODO(cbentzel): Move towards model of parsing in the factory
   //                 method and only constructing when valid.
   scoped_refptr<HttpAuthHandler> tmp_handler(
-      new HttpAuthHandlerNegotiate(sspi_library_, max_token_length_));
+      new HttpAuthHandlerNegotiate(sspi_library_, max_token_length_,
+                                   disable_cname_lookup_, use_port_));
   if (!tmp_handler->InitFromChallenge(challenge, target, origin))
     return ERR_INVALID_RESPONSE;
   handler->swap(tmp_handler);
   return OK;
 }
 
 }  // namespace net