modules/woff2/RLBoxWOFF2Sandbox.cpp

   1 /* -*- Mode: C++; tab-width: 8; 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 #include <woff2/decode.h>
   8 #include <cassert>
   9 #include "RLBoxWOFF2Sandbox.h"
  10
  11 bool RLBoxConvertWOFF2ToTTF(const char* aData, unsigned long aLength,
  12                             unsigned long aDecompressedSize,
  13                             unsigned long* aResultSize, void** aResultOwningStr,
  14                             char** aResultData) {
  15   std::unique_ptr<std::string> buf =
  16       std::make_unique<std::string>(aDecompressedSize, 0);
  17   woff2::WOFF2StringOut out(buf.get());
  18   if (!woff2::ConvertWOFF2ToTTF(reinterpret_cast<const uint8_t*>(aData),
  19                                 aLength, &out)) {
  20     return false;
  21   }
  22   *aResultSize = out.Size();
  23   // Return the string and its underlying C string. We need both to make sure we
  24   // can free the string (which we do with RLBoxDeleteWOFF2String).
  25   *aResultData = buf->data();
  26   *aResultOwningStr = static_cast<void*>(buf.release());
  27   return true;
  28 }
  29
  30 void RLBoxDeleteWOFF2String(void** aStr) {
  31   std::string* buf = static_cast<std::string*>(*aStr);
  32   delete buf;
  33 }
  34
  35 BrotliDecompressCallback* sRLBoxBrotliDecompressCallback = nullptr;
  36
  37 void RegisterWOFF2Callback(BrotliDecompressCallback* aCallback) {
  38 #ifdef MOZ_IN_WASM_SANDBOX
  39   // When Woff2 is wasmboxed, we need to register a callback for brotli
  40   // decompression. The easiest way to store this is in a static variable. This
  41   // is thread-safe because each (potentially-concurrent) woff2 instance gets
  42   // its own sandbox with its own copy of the statics.
  43   //
  44   // When the sandbox is disabled (replaced with the noop sandbox), setting the
  45   // callback is actually racey. However, we don't actually need a callback in
  46   // that case, and can just invoke brotli directly.
  47   sRLBoxBrotliDecompressCallback = aCallback;
  48 #endif
  49 }
  50
  51 BrotliDecoderResult RLBoxBrotliDecoderDecompress(size_t aEncodedSize,
  52                                                  const uint8_t* aEncodedBuffer,
  53                                                  size_t* aDecodedSize,
  54                                                  uint8_t* aDecodedBuffer) {
  55 #ifdef MOZ_IN_WASM_SANDBOX
  56   assert(sRLBoxBrotliDecompressCallback);
  57   return sRLBoxBrotliDecompressCallback(
  58       aEncodedSize, reinterpret_cast<const char*>(aEncodedBuffer), aDecodedSize,
  59       reinterpret_cast<char*>(aDecodedBuffer));
  60 #else
  61   return BrotliDecoderDecompress(aEncodedSize, aEncodedBuffer, aDecodedSize,
  62                                  aDecodedBuffer);
  63 #endif
  64 }