sandbox/linux/suid/client/setuid_sandbox_host.h

   1 // Copyright 2015 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_HOST_H_
   6 #define SANDBOX_LINUX_SUID_SETUID_SANDBOX_HOST_H_
   7
   8 #include "base/files/file_path.h"
   9 #include "base/files/scoped_file.h"
  10 #include "base/macros.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/process/launch.h"
  13 #include "sandbox/sandbox_export.h"
  14
  15 namespace sandbox {
  16
  17 // Helper class to use the setuid sandbox. This class is to be used
  18 // before launching the setuid helper.
  19 // This class is difficult to use. It has been created by refactoring very old
  20 // code scathered through the Chromium code base.
  21 //
  22 // A typical use for "A" launching a sandboxed process "B" would be:
  23 // 1. A calls SetupLaunchEnvironment()
  24 // 2. A sets up a base::CommandLine and then amends it with
  25 //    PrependWrapper() (or manually, by relying on GetSandboxBinaryPath()).
  26 // 3. A uses SetupLaunchOptions() to arrange for a dummy descriptor for the
  27 //    setuid sandbox ABI.
  28 // 4. A launches B with base::LaunchProcess, using the amended
  29 // base::CommandLine.
  30 // (The remaining steps are described within setuid_sandbox_client.h.)
  31 class SANDBOX_EXPORT SetuidSandboxHost {
  32  public:
  33   // All instantation should go through this factory method.
  34   static SetuidSandboxHost* Create();
  35   ~SetuidSandboxHost();
  36
  37   // The setuid sandbox may still be disabled via the environment.
  38   // This is tracked in crbug.com/245376.
  39   bool IsDisabledViaEnvironment();
  40   // Get the sandbox binary path. This method knows about the
  41   // CHROME_DEVEL_SANDBOX environment variable used for user-managed builds. If
  42   // the sandbox binary cannot be found, it will return an empty FilePath.
  43   base::FilePath GetSandboxBinaryPath();
  44   // Modify |cmd_line| to launch via the setuid sandbox. Crash if the setuid
  45   // sandbox binary cannot be found.  |cmd_line| must not be NULL.
  46   void PrependWrapper(base::CommandLine* cmd_line);
  47   // Set-up the launch options for launching via the setuid sandbox.  Caller is
  48   // responsible for keeping |dummy_fd| alive until LaunchProcess() completes.
  49   // |options| and |fds_to_remap| must not be NULL.
  50   // (Keeping |dummy_fd| alive is an unfortunate historical artifact of the
  51   // chrome-sandbox ABI.)
  52   void SetupLaunchOptions(base::LaunchOptions* options,
  53                           base::FileHandleMappingVector* fds_to_remap,
  54                           base::ScopedFD* dummy_fd);
  55   // Set-up the environment. This should be done prior to launching the setuid
  56   // helper.
  57   void SetupLaunchEnvironment();
  58
  59  private:
  60   explicit SetuidSandboxHost(base::Environment* env);
  61
  62   // Holds the environment. Will never be NULL.
  63   scoped_ptr<base::Environment> env_;
  64
  65   DISALLOW_COPY_AND_ASSIGN(SetuidSandboxHost);
  66 };
  67
  68 }  // namespace sandbox
  69
  70 #endif  // SANDBOX_LINUX_SUID_SETUID_SANDBOX_HOST_H_