Security patches: RestartJob ignores pid, argv[0]; kill runs as child UID

system_utils.h

 // Copyright (c) 2010 The Chromium OS 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 LOGIN_MANAGER_SYSTEM_UTILS_H_
 #define LOGIN_MANAGER_SYSTEM_UTILS_H_
 
 #include <unistd.h>
 
 #include <base/basictypes.h>
 
 class FilePath;
 
 namespace login_manager {
 class SystemUtils {
  public:
   SystemUtils();
   virtual ~SystemUtils();
 
-  virtual int kill(pid_t pid, int signal);
+  // Sends |signal| to |pid|, with uid and euid set to |owner|.
+  // NOTE: Your saved UID is kept unchanged.  If you expect to drop and regain
+  // root privs, MAKE SURE YOUR suid == 0.
+  virtual int kill(pid_t pid, uid_t owner, int signal);
 
   // Returns: true if child specified by |child_spec| exited,
   //          false if we time out.
   virtual bool ChildIsGone(pid_t child_spec, int timeout);
 
   virtual bool EnsureAndReturnSafeFileSize(const FilePath& file,
                                            int32* file_size_32);
 
   virtual bool EnsureAndReturnSafeSize(int64 size_64, int32* size_32);
 
   // Atomically writes the given buffer into the file, overwriting any
   // data that was previously there.  Returns the number of bytes
   // written, or -1 on error.
   virtual bool AtomicFileWrite(const FilePath& filename,
                                const char* data,
                                int size);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SystemUtils);
 };
 }  // namespace login_manager
 
 #endif  // LOGIN_MANAGER_SYSTEM_UTILS_H_