Harden untrusted payload parsing against out-of-bounds access - #9
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Validate buffers in CreateReadonly, thread received size through field and vector accessors, clamp hostile string lengths and element counts, and fix ProtoBuffer overflow so malicious wire data cannot read past the buffer.
Make presence, nested-message slots, string size/data, fixed-array counts, vector BaseOffset/capacity, and union discriminators size-aware so hostile payloads cannot read past the received buffer.
libFuzzer found UnionInt64Field::Get SEGVing on hostile inflated full_size; route union primitives through MessageRuntime::ToAddress. Pin cpp_toolbelt to the ToAddress sizeof-fit fix and keep ASan crash inputs as regression corpus.
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Summary
CreateReadonlybefore dereferencing any field offsetsbuffer_sizethroughMessageRuntimefor size-aware string reads and element-count clampingProtoBuffer::Checkinteger overflow on hostile wire lengthsPhaserTest.HostilePayloadIsBoundedcpp_toolbeltto dallison/cpp_toolbelt#26 viagit_overrideuntil 2.1.3 is publishedTest plan
bazel test //... -//phaser:perf_test(macOS)bazel test //... -//phaser:perf_test(Linux via Colima/Ubuntu 24.04)bazel test --config=asan //... -//phaser:perf_test(Linux — ASan hangs on local macOS clang)Dependency
Requires merging and releasing cpp_toolbelt#26, then replacing the temporary
git_overridewith acpp_toolbeltversion bump.