[professor-moody]

Summary

This change extends existing deserialization and reconstruction bounds checks to two remaining sibling code paths:

1. read_ResidualQuantizer_old and "IxRQ" / "IxRq" reader (faiss/impl/index_read.cpp):

   • read_ResidualQuantizer, read_LocalSearchQuantizer, and read_ProductAdditiveQuantizer call validate_codebooks_size(const AdditiveQuantizer& aq, size_t effective_d) so that additive quantizers with a truncated codebooks buffer are rejected during read_index().
   • The legacy reader read_ResidualQuantizer_old (used by the "IxRQ" fourcc branch) sits above validate_codebooks_size in faiss/impl/index_read.cpp and did not call it after rq.set_derived_values(). Forward-declaring validate_codebooks_size and calling validate_codebooks_size(rq, rq.d) at the end of read_ResidualQuantizer_old (allowing an early return only when !aq.is_trained && aq.codebooks.empty()) ensures legacy residual quantizer streams enforce codebooks.size() >= d * total_codebook_size before AdditiveQuantizer::decode or compute_codes indexes codebooks.
   • Additionally, in the "IxRQ" / "IxRq" IndexResidualQuantizer reader block, enforce idxr->rq.is_trained == idxr->is_trained and idxr->ntotal == 0 || idxr->rq.is_trained so a stream cannot mark the outer index trained (or populate ntotal > 0 codes) while leaving the inner ResidualQuantizer untrained with empty codebooks.

2. IndexBinaryIVF::reconstruct_from_offset (faiss/IndexBinaryIVF.cpp):

   • Float IndexIVF::reconstruct validates list_no and offset at runtime because DirectMap::get(key) does not validate the decoded (list_no, offset) pair stored in a serialized direct_map and assertions inside ArrayInvertedLists are compiled out under NDEBUG.
   • Adding runtime FAISS_THROW_IF_NOT_FMT checks on list_no >= 0 && static_cast<uint64_t>(list_no) < static_cast<uint64_t>(nlist) and offset >= 0 && static_cast<uint64_t>(offset) < static_cast<uint64_t>(invlists->list_size(list_no)) in IndexBinaryIVF::reconstruct_from_offset protects both IndexBinaryIVF::reconstruct(key, recons) and IndexBinaryIVF::search_and_reconstruct without 32-bit size_t truncation.

Test Plan

• Verified with regression tests covering:
  • Legacy "IxRQ" deserialization with valid codebooks (control), truncated codebooks with rq.is_trained = true (mode_rq_old), and inconsistent outer idxr->is_trained = true, ntotal = 1 with inner rq.is_trained = false (mode_rq_old_untrained_mismatch).
  • Binary IVF ("IBIv") reconstruction with valid DirectMap::Array entries (control) and out-of-bounds (list_no, offset) entries (offset >= list_size(list_no) and list_no >= nlist).
• Confirmed clean pass under both Release (-O3 -DNDEBUG) and ASan+UBSan (-fsanitize=address,undefined -g -O1).

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Note: This patch was prepared with AI assistance and verified by human review and local test execution.

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[meta-codesync]

@trang-nm-nguyen has imported this pull request. If you are a Meta employee, you can view this in D126706046.

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[ability-spec]

Looks good to me