diff options
Diffstat (limited to 'patch_reader.cc')
| -rw-r--r-- | patch_reader.cc | 44 |
1 files changed, 42 insertions, 2 deletions
diff --git a/patch_reader.cc b/patch_reader.cc index 8215405..90f35f4 100644 --- a/patch_reader.cc +++ b/patch_reader.cc @@ -13,6 +13,19 @@ namespace zucchini { +namespace { + +bool RangeIsInRegion(offset_t begin, uint32_t size, BufferRegion region) { + // Return false if |begin + size > kOffsetBound|, without overflowing. + if (begin >= kOffsetBound || kOffsetBound - begin < size) + return false; + offset_t end = begin + size; + // Return false if |[begin, end]| leaks outside |region|. + return begin >= region.lo() && end <= region.hi(); +} + +} // namespace + namespace patch { bool ParseElementMatch(BufferSource* source, ElementMatch* element_match) { @@ -217,7 +230,7 @@ PatchElementReader::~PatchElementReader() = default; bool PatchElementReader::Initialize(BufferSource* source) { bool ok = patch::ParseElementMatch(source, &element_match_) && - equivalences_.Initialize(source) && + equivalences_.Initialize(source) && ValidateEquivalences() && extra_data_.Initialize(source) && raw_delta_.Initialize(source) && reference_delta_.Initialize(source); if (!ok) @@ -240,7 +253,7 @@ bool PatchElementReader::Initialize(BufferSource* source) { } auto insert_result = extra_targets_.insert({pool_tag, {}}); if (!insert_result.second) { // Element already present. - LOG(ERROR) << "Multiple ExtraTargetList found for the same pool_tag"; + LOG(ERROR) << "Multiple ExtraTargetList found for the same pool_tag."; return false; } if (!insert_result.first->second.Initialize(source)) @@ -249,6 +262,33 @@ bool PatchElementReader::Initialize(BufferSource* source) { return true; } +bool PatchElementReader::ValidateEquivalences() { + EquivalenceSource equivalences_copy = equivalences_; + + BufferRegion old_region = element_match_.old_element.region(); + BufferRegion new_region = element_match_.new_element.region(); + + // Validate that each |equivalence| falls within the bounds of the + // |element_match_| and are in order. + offset_t prev_dst_end = 0; + for (auto equivalence = equivalences_copy.GetNext(); equivalence.has_value(); + equivalence = equivalences_copy.GetNext()) { + if (!RangeIsInRegion(equivalence->src_offset, equivalence->length, + old_region) || + !RangeIsInRegion(equivalence->dst_offset, equivalence->length, + new_region)) { + LOG(ERROR) << "Out of bounds equivalence detected."; + return false; + } + if (prev_dst_end > equivalence->dst_end()) { + LOG(ERROR) << "Out of order equivalence detected."; + return false; + } + prev_dst_end = equivalence->dst_end(); + } + return true; +} + /******** EnsemblePatchReader ********/ base::Optional<EnsemblePatchReader> EnsemblePatchReader::Create( |