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