| // Copyright 2015 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 SANDBOX_LINUX_SERVICES_NAMESPACE_UTILS_H_ |
| #define SANDBOX_LINUX_SERVICES_NAMESPACE_UTILS_H_ |
| |
| #include <sys/types.h> |
| |
| #include "base/compiler_specific.h" |
| #include "base/macros.h" |
| #include "base/template_util.h" |
| #include "sandbox/sandbox_export.h" |
| |
| namespace sandbox { |
| |
| // Utility functions for using Linux namepaces. |
| class SANDBOX_EXPORT NamespaceUtils { |
| public: |
| static_assert((base::is_same<uid_t, gid_t>::value), |
| "uid_t and gid_t must be the same type"); |
| // generic_id_t can be used for either uid_t or gid_t. |
| typedef uid_t generic_id_t; |
| |
| // Write a uid or gid mapping from |id| to |id| in |map_file|. This function |
| // is async-signal-safe. |
| static bool WriteToIdMapFile(const char* map_file, |
| generic_id_t id) WARN_UNUSED_RESULT; |
| |
| // Returns true if unprivileged namespaces of type |type| is supported |
| // (meaning that both CLONE_NEWUSER and type are are supported). |type| must |
| // be one of CLONE_NEWIPC, CLONE_NEWNET, CLONE_NEWNS, CLONE_NEWPID, |
| // CLONE_NEWUSER, or CLONE_NEWUTS. This relies on access to /proc, so it will |
| // not work from within a sandbox. |
| static bool KernelSupportsUnprivilegedNamespace(int type); |
| |
| // Returns true if the kernel supports denying setgroups in a user namespace. |
| // On kernels where this is supported, DenySetgroups must be called before a |
| // gid mapping can be added. |
| static bool KernelSupportsDenySetgroups(); |
| |
| // Disables setgroups() within the current user namespace. On Linux 3.18.2 and |
| // later, this is required in order to write to /proc/self/gid_map without |
| // having CAP_SETGID. Callers can determine whether is this needed with |
| // KernelSupportsDenySetgroups. This function is async-signal-safe. |
| static bool DenySetgroups() WARN_UNUSED_RESULT; |
| |
| private: |
| DISALLOW_IMPLICIT_CONSTRUCTORS(NamespaceUtils); |
| }; |
| |
| } // namespace sandbox |
| |
| #endif // SANDBOX_LINUX_SERVICES_NAMESPACE_UTILS_H_ |