Linux: add a Credentials class to handle Linux capabilities.

sandbox/linux/services/credentials.h

Index: sandbox/linux/services/credentials.h
diff --git a/sandbox/linux/services/credentials.h b/sandbox/linux/services/credentials.h
new file mode 100644
index 0000000000000000000000000000000000000000..3ea3cfc984ee1606ad4ac03041ee0d5a8f403d8e
--- /dev/null
+++ b/sandbox/linux/services/credentials.h
@@ -0,0 +1,46 @@
+// 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 "base/basictypes.h"
+#include "base/memory/scoped_ptr.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 Credentials {
+ public:
+  Credentials();
+  ~Credentials();
+
+  // Drop all capabilities in the effective, inheritable and permitted sets for
+  // the current process.
+  void DropAllCapabilities();
+  // Return true iff there is any capability in any of the capabilities sets
+  // of the current process.
+  bool HasAnyCapability();

[Jorge Lucangeli Obes, 2013/10/31 20:55:32]

Does your PoC use the API like this? Seems like a weird way to query.

[jln (very slow on Chromium), 2013/10/31 21:02:22]

Ohh, this is mostly for CHECK / DCHECK. The API as-is here is indeed not very
useful.

I wanted to land something small first to use libcap and deal with the fallout
of that. I'll send other cls soon.

(So far libcap still doesn't work on the bots, crbug.com/312572).

+  // Returns the capabilities of the current process in textual form, as
+  // documented in libcap2's cap_to_text(3). This is mostly useful for
+  // debugging and tests.
+  scoped_ptr<std::string> GetCurrentCapString();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(Credentials);
+};
+
+}  // namespace sandbox.
+
+#endif  // SANDBOX_LINUX_SERVICES_CREDENTIALS_H_