xpcom/base/RLBoxUtils.h

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef SECURITY_RLBOX_UTILS_H_
   8 #define SECURITY_RLBOX_UTILS_H_
   9
  10 #include "mozilla/rlbox/rlbox_types.hpp"
  11
  12 namespace mozilla {
  13
  14 /* The RLBoxTransferBufferToSandbox class is used to copy (or directly expose in
  15  * the noop-sandbox case) buffers into the sandbox that are automatically freed
  16  * when the RLBoxTransferBufferToSandbox is out of scope.  NOTE: The sandbox
  17  * lifetime must outlive all of its RLBoxTransferBufferToSandbox.
  18  */
  19 template <typename T, typename S>
  20 class MOZ_STACK_CLASS RLBoxTransferBufferToSandbox {
  21  public:
  22   RLBoxTransferBufferToSandbox() = delete;
  23   RLBoxTransferBufferToSandbox(rlbox::rlbox_sandbox<S>* aSandbox, const T* aBuf,
  24                                const size_t aLen)
  25       : mSandbox(aSandbox), mCopied(false), mBuf(nullptr) {
  26     if (aBuf) {
  27       mBuf = rlbox::copy_memory_or_grant_access(*mSandbox, aBuf, aLen, false,
  28                                                 mCopied);
  29     }
  30   };
  31   ~RLBoxTransferBufferToSandbox() {
  32     if (mCopied) {
  33       mSandbox->free_in_sandbox(mBuf);
  34     }
  35   };
  36   rlbox::tainted<const T*, S> operator*() const { return mBuf; };
  37
  38  private:
  39   rlbox::rlbox_sandbox<S>* mSandbox;
  40   bool mCopied;
  41   rlbox::tainted<const T*, S> mBuf;
  42 };
  43
  44 /* The RLBoxAllocateInSandbox class is used to allocate data int sandbox that is
  45  * automatically freed when the RLBoxAllocateInSandbox is out of scope.  NOTE:
  46  * The sandbox lifetime must outlive all of its RLBoxAllocateInSandbox'ations.
  47  */
  48 template <typename T, typename S>
  49 class MOZ_STACK_CLASS RLBoxAllocateInSandbox {
  50  public:
  51   RLBoxAllocateInSandbox() = delete;
  52   explicit RLBoxAllocateInSandbox(rlbox::rlbox_sandbox<S>* aSandbox)
  53       : mSandbox(aSandbox) {
  54     mPtr = mSandbox->template malloc_in_sandbox<T>();
  55   };
  56   ~RLBoxAllocateInSandbox() {
  57     if (mPtr) {
  58       mSandbox->free_in_sandbox(mPtr);
  59     }
  60   };
  61   rlbox::tainted<T*, S> get() const { return mPtr; };
  62
  63  private:
  64   rlbox::rlbox_sandbox<S>* mSandbox;
  65   rlbox::tainted<T*, S> mPtr;
  66 };
  67
  68 }  // namespace mozilla
  69
  70 #endif