1 files changed, 104 insertions, 0 deletions
diff --git a/sandbox/linux/services/credentials.h b/sandbox/linux/services/credentials.h
new file mode 100644
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+++ b/sandbox/linux/services/credentials.h
@@ -0,0 +1,104 @@
+// Copyright (c) 2013 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_CREDENTIALS_H_
+#define SANDBOX_LINUX_SERVICES_CREDENTIALS_H_
+
+#include "build/build_config.h"
+// Link errors are tedious to track, raise a compile-time error instead.
+#if defined(OS_ANDROID)
+#error "Android is not supported."
+#endif  // defined(OS_ANDROID).
+
+#include <string>
+#include <vector>
+
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "sandbox/linux/system_headers/capability.h"
+#include "sandbox/sandbox_export.h"
+
+namespace sandbox {
+
+// This class should be used to manipulate the current process' credentials.
+// It is currently a stub used to manipulate POSIX.1e capabilities as
+// implemented by the Linux kernel.
+class SANDBOX_EXPORT Credentials {
+ public:
+  // For brevity, we only expose enums for the subset of capabilities we use.
+  // This can be expanded as the need arises.
+  enum class Capability {
+    SYS_CHROOT,
+    SYS_ADMIN,
+  };
+
+  // Drop all capabilities in the effective, inheritable and permitted sets for
+  // the current thread. For security reasons, since capabilities are
+  // per-thread, the caller is responsible for ensuring it is single-threaded
+  // when calling this API.
+  // |proc_fd| must be a file descriptor to /proc/ and remains owned by
+  // the caller.
+  static bool DropAllCapabilities(int proc_fd) WARN_UNUSED_RESULT;
+  // A similar API which assumes that it can open /proc/self/ by itself.
+  static bool DropAllCapabilities() WARN_UNUSED_RESULT;
+  // Sets the effective and permitted capability sets for the current thread to
+  // the list of capabiltiies in |caps|. All other capability flags are cleared.
+  static bool SetCapabilities(int proc_fd,
+                              const std::vector<Capability>& caps)
+      WARN_UNUSED_RESULT;
+
+  // Versions of the above functions which do not check that the process is
+  // single-threaded. After calling these functions, capabilities of other
+  // threads will not be changed. This is dangerous, do not use unless you nkow
+  // what you are doing.
+  static bool DropAllCapabilitiesOnCurrentThread() WARN_UNUSED_RESULT;
+  static bool SetCapabilitiesOnCurrentThread(
+      const std::vector<Capability>& caps) WARN_UNUSED_RESULT;
+
+  // Returns true if the current thread has either the effective, permitted, or
+  // inheritable flag set for the given capability.
+  static bool HasCapability(Capability cap);
+
+  // Return true iff there is any capability in any of the capabilities sets
+  // of the current thread.
+  static bool HasAnyCapability();
+
+  // Returns whether the kernel supports CLONE_NEWUSER and whether it would be
+  // possible to immediately move to a new user namespace. There is no point
+  // in using this method right before calling MoveToNewUserNS(), simply call
+  // MoveToNewUserNS() immediately. This method is only useful to test the
+  // ability to move to a user namespace ahead of time.
+  static bool CanCreateProcessInNewUserNS();
+
+  // Move the current process to a new "user namespace" as supported by Linux
+  // 3.8+ (CLONE_NEWUSER).
+  // The uid map will be set-up so that the perceived uid and gid will not
+  // change.
+  // If this call succeeds, the current process will be granted a full set of
+  // capabilities in the new namespace.
+  // This will fail if the process is not mono-threaded.
+  static bool MoveToNewUserNS() WARN_UNUSED_RESULT;
+
+  // Remove the ability of the process to access the file system. File
+  // descriptors which are already open prior to calling this API remain
+  // available.
+  // The implementation currently uses chroot(2) and requires CAP_SYS_CHROOT.
+  // CAP_SYS_CHROOT can be acquired by using the MoveToNewUserNS() API.
+  // |proc_fd| must be a file descriptor to /proc/ and must be the only open
+  // directory file descriptor of the process.
+  //
+  // CRITICAL:
+  //   - the caller must close |proc_fd| eventually or access to the file
+  // system can be recovered.
+  //   - DropAllCapabilities() must be called to prevent escapes.
+  static bool DropFileSystemAccess(int proc_fd) WARN_UNUSED_RESULT;
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Credentials);
+};
+
+}  // namespace sandbox.
+
+#endif  // SANDBOX_LINUX_SERVICES_CREDENTIALS_H_