Harden GLB header and material factor parsing against malformed input - #179
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SergioRZMasson merged 1 commit intoJul 30, 2026
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…array lengths GLBResourceReader::Init computed the GLB header/chunk size checks (GLB_HEADER_BYTE_SIZE + jsonChunkLength, and the component-chunk size sum) using 32-bit arithmetic. For a large 32-bit JSON chunk length the addition can wrap, producing a value smaller than the actual file length so the size check passes incorrectly and ReadJson is then asked for a very large allocation. Perform these additions in 64-bit (uint64_t) so the sums cannot wrap; the comparisons against the 32-bit file length are unchanged in behavior for all valid files. ParseMaterial read baseColorFactor[0..3] and emissiveFactor[0..2] by fixed index without checking how many elements were parsed. When the caller disables schema validation (SchemaFlags::DisableSchemaRoot), a shorter array would be read beyond the elements that were provided. Validate the element count (4 and 3 respectively) on the core parsing path, independent of schema flags, throwing InvalidGLTFException otherwise. Adds regression tests: a GLB with a 0xFFFFFFFF JSON chunk length is now rejected, and short baseColorFactor/emissiveFactor arrays are rejected under SchemaFlags::DisableSchemaRoot. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 039828de-4db2-48f8-a5de-c9f7d33baffa
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GLBResourceReader::Init computed the GLB header/chunk size checks (GLB_HEADER_BYTE_SIZE + jsonChunkLength, and the component-chunk size sum) in 32-bit arithmetic. A maximal 32-bit JSON chunk length wraps the sum below the real file length, bypassing the "file length covers the header + JSON chunk" guard and letting ReadJson attempt an allocation of up to ~4 GB from a tiny file. Perform these additions in 64-bit (uint64_t) so the sums cannot wrap; the comparisons against the 32-bit file length are unchanged in behavior for all valid files.
ParseMaterial read baseColorFactor[0..3] and emissiveFactor[0..2] by fixed index without checking the parsed element count. When schema validation is disabled by the caller (SchemaFlags::DisableSchemaRoot), a short array leads to an out-of-bounds read past the parsed vector. Validate the element count (4 and 3 respectively) on the core parsing path, independent of schema flags, throwing InvalidGLTFException otherwise.
Adds regression tests: a GLB with a 0xFFFFFFFF JSON chunk length is now rejected, and short baseColorFactor/emissiveFactor arrays are rejected under SchemaFlags::DisableSchemaRoot.