Authenticate user/password with PAM in BeginSessionRequest()

remoting/host/user_authenticator_pam.h

Index: remoting/host/user_authenticator_pam.h
diff --git a/remoting/host/user_authenticator_pam.h b/remoting/host/user_authenticator_pam.h
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+// Copyright (c) 2011 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.
+
+#ifndef REMOTING_HOST_USER_AUTHENTICATOR_PAM_H_
+#define REMOTING_HOST_USER_AUTHENTICATOR_PAM_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "remoting/host/user_authenticator.h"
+
+struct pam_message;
+struct pam_response;
+
+namespace remoting {
+
+// Class to perform a single PAM user authentication.
+//
+// TODO(lambroslambrou): As pam_authenticate() can be blocking, this needs to
+// expose an asynchronous API, with pam_authenticate() called in a background
+// thread.
+class UserAuthenticatorPam : public UserAuthenticator {
+ public:
+  UserAuthenticatorPam();
+  virtual ~UserAuthenticatorPam();
+  virtual bool Authenticate(const std::string& username,
+                            const std::string& password);
+
+ private:
+  // Conversation function passed to PAM as a callback.
+  static int ConvFunction(int num_msg,
+                          const pam_message** msg,
+                          pam_response** resp,
+                          void* appdata_ptr);
+
+  // Store these for the PAM conversation function.
+  std::string username_;
+  std::string password_;
+
+  DISALLOW_COPY_AND_ASSIGN(UserAuthenticatorPam);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_USER_AUTHENTICATOR_PAM_H_