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fix: use-after-realloc in addManyNumbers (#517) #522

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fix: use-after-realloc in addManyNumbers (#517) #522

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8 changes: 7 additions & 1 deletion src/binaryArith.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -914,6 +914,12 @@ void addManyNumbers(CtPtrs& sum,

bool bootstrappable = ct_ptr->getPubKey().isBootstrappable();
const EncryptedArray& ea = ct_ptr->getContext().getEA();
// Cache the bit-per-level threshold before the loop: three4Two below may
// resize the NTL::Vec<Ctxt> that ct_ptr points into, reallocating the
// underlying storage and leaving ct_ptr dangling. Dereferencing ct_ptr
// on a later iteration then reads freed memory (issue #517).
const long minCapacityThreshold = 3 * ct_ptr->getContext().BPL();
ct_ptr = nullptr;

long leftInQ = lsize(numbers);
std::vector<CtPtrs*> numPtrs(leftInQ);
Expand All @@ -924,7 +930,7 @@ void addManyNumbers(CtPtrs& sum,
while (leftInQ > 2) {
// If any number is too low level, then bootstrap everything
PtrMatrix_PtPtrVector<Ctxt> wrapper(numPtrs);
if (findMinBitCapacity(wrapper) < 3 * ct_ptr->getContext().BPL()) {
if (findMinBitCapacity(wrapper) < minCapacityThreshold) {
assertNotNull<InvalidArgument>(unpackSlotEncoding,
"unpackSlotEncoding must not be null");
assertTrue(bootstrappable,
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