sandbox/linux/suid/client/setuid_sandbox_client.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef SANDBOX_LINUX_SUID_SETUID_SANDBOX_CLIENT_H_
   6 #define SANDBOX_LINUX_SUID_SETUID_SANDBOX_CLIENT_H_
   7
   8 #include "base/environment.h"
   9 #include "base/macros.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "sandbox/sandbox_export.h"
  12
  13 namespace sandbox {
  14
  15 // Helper class to use the setuid sandbox. This class is to be used
  16 // after being executed through the setuid helper.
  17 // This class is difficult to use. It has been created by refactoring very old
  18 // code scathered through the Chromium code base.
  19 //
  20 // A typical use for "A" launching a sandboxed process "B" would be:
  21 // (Steps 1 through 4 are described in setuid_sandbox_host.h.)
  22 // 5. B uses CloseDummyFile() to close the dummy file descriptor.
  23 // 6. B performs various initializations that require access to the file
  24 //    system.
  25 // 6.b (optional) B uses sandbox::Credentials::HasOpenDirectory() to verify
  26 //    that no directory is kept open (which would allow bypassing the setuid
  27 //    sandbox).
  28 // 7. B should be prepared to assume the role of init(1). In particular, B
  29 //    cannot receive any signal from any other process, excluding SIGKILL.
  30 //    If B dies, all the processes in the namespace will die.
  31 //    B can fork() and the parent can assume the role of init(1), by using
  32 //    sandbox::CreateInitProcessReaper().
  33 // 8. B requests being chroot-ed through ChrootMe() and
  34 //    requests other sandboxing status via the status functions.
  35 class SANDBOX_EXPORT SetuidSandboxClient {
  36  public:
  37   // All instantation should go through this factory method.
  38   static SetuidSandboxClient* Create();
  39   ~SetuidSandboxClient();
  40
  41   // Close the dummy file descriptor leftover from the sandbox ABI.
  42   void CloseDummyFile();
  43   // Ask the setuid helper over the setuid sandbox IPC channel to chroot() us
  44   // to an empty directory.
  45   // Will only work if we have been launched through the setuid helper.
  46   bool ChrootMe();
  47
  48   // Did we get launched through an up to date setuid binary ?
  49   bool IsSuidSandboxUpToDate() const;
  50   // Did we get launched through the setuid helper ?
  51   bool IsSuidSandboxChild() const;
  52   // Did the setuid helper create a new PID namespace ?
  53   bool IsInNewPIDNamespace() const;
  54   // Did the setuid helper create a new network namespace ?
  55   bool IsInNewNETNamespace() const;
  56   // Are we done and fully sandboxed ?
  57   bool IsSandboxed() const;
  58
  59  private:
  60   explicit SetuidSandboxClient(base::Environment* env);
  61
  62   // Holds the environment. Will never be NULL.
  63   scoped_ptr<base::Environment> env_;
  64   bool sandboxed_;
  65
  66   DISALLOW_COPY_AND_ASSIGN(SetuidSandboxClient);
  67 };
  68
  69 }  // namespace sandbox
  70
  71 #endif  // SANDBOX_LINUX_SUID_SETUID_SANDBOX_CLIENT_H_