code for encrypting sensitive tcmalloc metadata

third_party/tcmalloc/chromium/src/metadata_encrypt.h

+// Copyright (c) 2011, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// ---
+// Author: Rebecca Shapiro
+//
+// Here lies code that aids in encrypting allocator metadata.  Because
+// some, but not all operating systems provide pointer encryption
+// facilities, this header file is used to determine which encryption
+// implementation gets included in the build.
+
+
+#ifndef TCMALLOC_METADATA_ENCRYPT_H_
+#define TCMALLOC_METADATA_ENCRYPT_H_
+
+#ifdef TCMALLOC_SPAN_ENCRYPT
+#include "metadata_encrypt_generic.h"

[jschuh, 2011/09/13 16:37:12]

I'm assuming this is where the OS-specific ifdefs will go?

[bxx, 2011/09/13 19:36:09]

Yes, this is where they go once they exist.

+#else
+#include "metadata_encrypt_disabled.h"
+#endif
+
+#include <stdint.h>
+#include "span.h"
+
+namespace tcmalloc {
+
+inline Span *EncryptSpanPtr(Span *ptr){
+  return reinterpret_cast<Span *>(
+      EncryptUintptr(reinterpret_cast<uintptr_t>(ptr)));
+}
+
+inline Span *DecryptSpanPtr(Span *ptr){
+  return reinterpret_cast<Span *>(
+      DecryptUintptr(reinterpret_cast<uintptr_t>(ptr)));
+}
+
+}
+
+#endif // TCMALLOC_METADATA_ENCRYPT_H_