Add check if privileges were properly dropped

Check if every thread in process has same stats as thread
calling security_manager_prepare_app() and exit from process
if they do not.

Change-Id: I008c2b8e442edb6a5f9f1d74bf13f95465b6bdca
Signed-off-by: Rafal Krypa <r.krypa@samsung.com>

1 files changed, 76 insertions, 0 deletions

diff --git a/src/client/include/check-proper-drop.h b/src/client/include/check-proper-drop.h
new file mode 100644
index 00000000..ad1df5b5
--- /dev/null
+++ b/src/client/include/check-proper-drop.h
@@ -0,0 +1,76 @@
+/*
+ *  Copyright (c) 2015 Samsung Electronics Co., Ltd All Rights Reserved
+ *
+ *  Contact: Rafal Krypa <r.krypa@samsung.com>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License
+ */
+/*
+ * @file        check-proper-drop.h
+ * @author      Rafal Krypa <r.krypa@samsung.com>
+ * @version     1.0
+ * @brief       Definition of proper privilege dropping check utilities
+ */
+
+#ifndef SECURITY_MANAGER_CHECK_PROPER_DROP_
+#define SECURITY_MANAGER_CHECK_PROPER_DROP_
+
+#include <dpl/exception.h>
+
+#include <unistd.h>
+#include <proc/readproc.h>
+
+#include <vector>
+
+namespace SecurityManager {
+
+class CheckProperDrop {
+public:
+    class Exception {
+    public:
+        DECLARE_EXCEPTION_TYPE(SecurityManager::Exception, Base)
+        DECLARE_EXCEPTION_TYPE(Base, ProcError)
+        DECLARE_EXCEPTION_TYPE(Base, CapError)
+    };
+
+    ~CheckProperDrop();
+    CheckProperDrop(pid_t pid = getpid()) : m_pid(pid) {};
+
+    /**
+     * Fetch credentials of the process and all its threads.
+     * Must be called before checkThreads().
+     */
+    void getThreads();
+
+    /**
+     * Check whether all threads of the process has properly aligned
+     * credentials:
+     * - uids
+     * - gids
+     * - capabilities
+     * - Smack labels
+     *
+     * It will terminate the calling process if any thread has different
+     * value than the other threads. This prevents security risks associated
+     * with improperly dropped privileges during application launch.
+     */
+    bool checkThreads();
+
+private:
+    pid_t m_pid;
+    proc_t *m_proc = nullptr;
+    std::vector<proc_t*> m_threads;
+};
+
+} // namespace SecurityManager
+#endif /* SECURITY_MANAGER_CHECK_PROPER_DROP_H_ */