Host-side third party token validation

remoting/host/host_token_validator_factory.cc

+// Copyright (c) 2012 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 "remoting/host/host_token_validator_factory.h"
+
+#include <set>
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/json/json_reader.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/single_thread_task_runner.h"
+#include "base/supports_user_data.h"

[Wez, 2013/03/06 01:01:08]

Is this include required?

[rmsousa, 2013/03/25 22:45:58]

Done.

+#include "base/thread_task_runner_handle.h"

[Wez, 2013/03/06 01:01:08]

Is this include necessary?

[rmsousa, 2013/03/25 22:45:58]

Done.

+#include "base/values.h"
+#include "googleurl/src/gurl.h"
+#include "net/base/escape.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_fetcher_delegate.h"
+#include "net/url_request/url_request_status.h"
+
+namespace remoting {
+
+class HostTokenValidator
+    : public net::URLFetcherDelegate,
+      public protocol::ThirdPartyAuthenticator::TokenValidator {
+ public:
+  HostTokenValidator(
+      scoped_refptr<net::URLRequestContextGetter> request_context_getter)
+      : request_context_getter_(request_context_getter) {
+  }
+
+  ~HostTokenValidator() {

[Wez, 2013/03/06 01:01:08]

nit: virtual

[rmsousa, 2013/03/25 22:45:58]

Done.

+  }
+
+  void ValidateThirdPartyToken(

[Wez, 2013/03/06 01:01:08]

nit: Add comment "TokenValidator interface."

[Wez, 2013/03/06 01:01:08]

virtual + OVERRIDE

[rmsousa, 2013/03/25 22:45:58]

Done.

[rmsousa, 2013/03/25 22:45:58]

Done.

+      const std::string& token_validation_url,
+      const std::string& token,
+      const std::string& host_public_key,
+      const std::string& token_signature,
+      const std::string& scope,
+      const base::Callback<void(
+          const std::string& shared_secret)>& on_token_validated) {
+    DCHECK(!request_);
+    DCHECK(!scope.empty());

[Wez, 2013/03/06 01:01:08]

nit: DCHECK e.g. that on_token_validated_ is non-null, and other parameters are
valid?

[rmsousa, 2013/03/25 22:45:58]

Done.

+    scope_ = scope;

[Wez, 2013/03/06 01:01:08]

nit: Space after DCHECKS, and after this parameter-saving block.

[rmsousa, 2013/03/25 22:45:58]

Done.

+    on_token_validated_ = on_token_validated;
+    std::string post_body =
+        "code=" + net::EscapeUrlEncodedData(token, true) +
+        "&client_id=" + net::EscapeUrlEncodedData(
+            host_public_key, true) +
+        "&client_secret=" + net::EscapeUrlEncodedData(
+            token_signature, true) +
+        "&grant_type=authorization_code";
+    request_.reset(net::URLFetcher::Create(
+        GURL(token_validation_url), net::URLFetcher::POST, this));
+    request_->SetUploadData("application/x-www-form-urlencoded", post_body);
+    request_->SetRequestContext(request_context_getter_);
+    request_->Start();
+  }
+
+  void OnURLFetchComplete(const net::URLFetcher* source) {

[Wez, 2013/03/06 01:01:08]

nit: Add comment "URLFetcherDelegate interface."

[Wez, 2013/03/06 01:01:08]

virtual + OVERRIDE

[rmsousa, 2013/03/25 22:45:58]

Done.

[rmsousa, 2013/03/25 22:45:58]

Done.

+    DCHECK_EQ(request_.get(), source);
+
+    on_token_validated_.Run(GetSharedSecretFromResponse(source));
+    request_.reset();

[Wez, 2013/03/06 01:01:08]

This will fail if the callback caused a new validation to be started, or caused
the validator to be torn down - can you reset |request_| before the callback?

[rmsousa, 2013/03/25 22:45:58]

Good catch. Done.

+  }
+
+ private:
+  bool ValidateScope(const std::string& scope) {

[Wez, 2013/03/06 01:01:08]

nit: IsValidScope()

[rmsousa, 2013/03/25 22:45:58]

Done.

+    // TODO(rmsousa): Deal with reordering/subsets/supersets/aliases/etc.
+    return scope == scope_;
+  }
+
+  std::string GetSharedSecretFromResponse(const net::URLFetcher* source) {
+    std::string shared_secret;

[Wez, 2013/03/06 01:01:08]

nit: Add a comment e.g. "Verify that we got a success response."

[rmsousa, 2013/03/25 22:45:58]

Done.

+    int response = source->GetResponseCode();
+    net::URLRequestStatus status = source->GetStatus();
+    std::string data;
+    if (!status.is_success() || response != 200) {
+      LOG(ERROR) <<
+          "Error " << response << " validating token: '" << data << "'";
+      return shared_secret;
+    }
+
+    source->GetResponseAsString(&data);

[Wez, 2013/03/06 01:01:08]

nit: Comment e.g. "Decode the JSON data from the response."

[rmsousa, 2013/03/25 22:45:58]

Done.

+    scoped_ptr<base::Value> value(base::JSONReader::Read(data));
+    if (!value.get() || value->GetType() != base::Value::TYPE_DICTIONARY) {
+      LOG(ERROR) << "Invalid token validation response: '" << data << "'";
+      return shared_secret;
+    }
+
+    DictionaryValue* dict = static_cast<DictionaryValue*>(value.get());

[Wez, 2013/03/06 01:01:08]

nit: Comment e.g. "Fetch the scope and check that it is valid."

[rmsousa, 2013/03/25 22:45:58]

Done.

+    std::string scope;
+    dict->GetStringWithoutPathExpansion("scope", &scope);
+    if (!ValidateScope(scope)) {
+      LOG(ERROR) <<
+          "Invalid scope: '" << scope << "', expected: '" << scope_ <<"'.";
+      return shared_secret;
+    }
+
+    dict->GetStringWithoutPathExpansion("access_token", &shared_secret);

[Wez, 2013/03/06 01:01:08]

nit: Comment e.g. "Scope was valid, so return the secret to the caller."

[rmsousa, 2013/03/25 22:45:58]

Done.

+    return shared_secret;
+  }
+
+  scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
+  scoped_ptr<net::URLFetcher> request_;
+  std::string scope_;
+  base::Callback<void(const std::string& shared_secret)> on_token_validated_;

[Wez, 2013/03/06 01:01:08]

nit: Blank line before DISALLOW...

[rmsousa, 2013/03/25 22:45:58]

Done.

+  DISALLOW_COPY_AND_ASSIGN(HostTokenValidator);
+};
+
+HostTokenValidatorFactory::HostTokenValidatorFactory(
+    scoped_refptr<net::URLRequestContextGetter> request_context_getter)
+  : request_context_getter_(request_context_getter) {
+}
+
+HostTokenValidatorFactory::~HostTokenValidatorFactory() {
+}
+
+scoped_ptr<protocol::ThirdPartyAuthenticator::TokenValidator>
+    HostTokenValidatorFactory::CreateTokenValidator() {
+  return scoped_ptr<protocol::ThirdPartyAuthenticator::TokenValidator>(
+      new HostTokenValidator(request_context_getter_));
+}
+
+}  // namespace remoting