1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "mojo/public/cpp/bindings/lib/bounds_checker.h"
7 #include "mojo/public/cpp/bindings/lib/bindings_serialization.h"
8 #include "mojo/public/cpp/environment/logging.h"
9 #include "mojo/public/cpp/system/handle.h"
14 BoundsChecker::BoundsChecker(const void* data, uint32_t data_num_bytes,
16 : data_begin_(reinterpret_cast<uintptr_t>(data)),
17 data_end_(data_begin_ + data_num_bytes),
19 handle_end_(static_cast<uint32_t>(num_handles)) {
20 if (data_end_ < data_begin_) {
21 // The calculation of |data_end_| overflowed.
22 // It shouldn't happen but if it does, set the range to empty so
23 // IsValidRange() and ClaimMemory() always fail.
24 MOJO_DCHECK(false) << "Not reached";
25 data_end_ = data_begin_;
27 if (handle_end_ < num_handles) {
28 // Assigning |num_handles| to |handle_end_| overflowed.
29 // It shouldn't happen but if it does, set the handle index range to empty.
30 MOJO_DCHECK(false) << "Not reached";
35 BoundsChecker::~BoundsChecker() {
38 bool BoundsChecker::ClaimMemory(const void* position, uint32_t num_bytes) {
39 uintptr_t begin = reinterpret_cast<uintptr_t>(position);
40 uintptr_t end = begin + num_bytes;
42 if (!InternalIsValidRange(begin, end))
49 bool BoundsChecker::ClaimHandle(const Handle& encoded_handle) {
50 uint32_t index = encoded_handle.value();
51 if (index == kEncodedInvalidHandleValue)
54 if (index < handle_begin_ || index >= handle_end_)
57 // |index| + 1 shouldn't overflow, because |index| is not the max value of
58 // uint32_t (it is less than |handle_end_|).
59 handle_begin_ = index + 1;
63 bool BoundsChecker::IsValidRange(const void* position,
64 uint32_t num_bytes) const {
65 uintptr_t begin = reinterpret_cast<uintptr_t>(position);
66 uintptr_t end = begin + num_bytes;
68 return InternalIsValidRange(begin, end);
71 bool BoundsChecker::InternalIsValidRange(uintptr_t begin, uintptr_t end) const {
72 return end > begin && begin >= data_begin_ && end <= data_end_;
75 } // namespace internal