Skip to content

GH-45086: [C++] Fix heap buffer overflow in FillNullForward/Backward … #50843

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
tonyroberts wants to merge 3 commits into
base: main
Choose a base branch
from
+71 −13
Open

GH-45086: [C++] Fix heap buffer overflow in FillNullForward/Backward … #50843

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
42d9862
GH-45086: [C++] Fix heap buffer overflow in FillNullForward/Backward …
tonyroberts Aug 10, 2026
9c2e6b6
Address review feedback: use PreallocateFixedWidthArrayData
tonyroberts Aug 11, 2026
d5d2dc2
MINOR: [C++] Fix clang-format lint failure in vector_replace_test.cc
tonyroberts Aug 12, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
24 changes: 11 additions & 13 deletions cpp/src/arrow/compute/kernels/vector_replace.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
#include "arrow/compute/kernels/util_internal.h"
#include "arrow/compute/registry_internal.h"
#include "arrow/util/bitmap_ops.h"
#include "arrow/util/fixed_width_internal.h"
#include "arrow/util/logging_internal.h"

namespace arrow {
Expand Down Expand Up @@ -422,12 +423,10 @@ struct ReplaceMaskChunked {
ExecResult chunk_result;
if (is_fixed_width(out->type()->id())) {
auto chunk_out = std::make_shared<ArrayData>(chunk->type(), chunk->length());
chunk_out->buffers.resize(2);
ARROW_ASSIGN_OR_RAISE(chunk_out->buffers[0],
ctx->AllocateBitmap(chunk->length()));
const int64_t slot_width = out->type()->byte_width();
ARROW_ASSIGN_OR_RAISE(chunk_out->buffers[1],
ctx->Allocate(slot_width * chunk->length()));
ArrayData* chunk_out_arr = chunk_out.get();
RETURN_NOT_OK(util::internal::PreallocateFixedWidthArrayData(
ctx, chunk->length(), /*source=*/*chunk->data(),
/*allocate_validity=*/true, chunk_out_arr));
chunk_result.value = chunk_out;
}
if (batch[1].is_scalar()) {
Expand Down Expand Up @@ -696,10 +695,9 @@ struct FillNullForwardChunked {
for (const std::shared_ptr<Array>& chunk : values.chunks()) {
if (is_fixed_width(out->type()->id())) {
ArrayData* output = out->mutable_array();
ARROW_ASSIGN_OR_RAISE(output->buffers[0], ctx->AllocateBitmap(chunk->length()));
ARROW_ASSIGN_OR_RAISE(
output->buffers[1],
ctx->Allocate(out->type()->byte_width() * chunk->length()));
RETURN_NOT_OK(util::internal::PreallocateFixedWidthArrayData(
ctx, chunk->length(), /*source=*/*chunk->data(),
/*allocate_validity=*/true, output));
}
ExecResult chunk_result;
chunk_result.value = out->array();
Expand Down Expand Up @@ -780,9 +778,9 @@ struct FillNullBackwardChunked {
const auto& chunk = chunks[i];
if (is_fixed_width(out->type()->id())) {
ArrayData* output = out->mutable_array();
auto data_bytes = output->type->byte_width() * chunk->length();
ARROW_ASSIGN_OR_RAISE(output->buffers[0], ctx->AllocateBitmap(chunk->length()));
ARROW_ASSIGN_OR_RAISE(output->buffers[1], ctx->Allocate(data_bytes));
RETURN_NOT_OK(util::internal::PreallocateFixedWidthArrayData(
ctx, chunk->length(), /*source=*/*chunk->data(),
/*allocate_validity=*/true, output));
}
ExecResult chunk_result;
chunk_result.value = out->array();
Expand Down
60 changes: 60 additions & 0 deletions cpp/src/arrow/compute/kernels/vector_replace_test.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -545,6 +545,24 @@ TEST_F(TestReplaceBoolean, ReplaceWithMask) {
}
}

// Regression test: ReplaceMaskChunked (the ChunkedArray path of replace_with_mask)
// sized each output chunk's data buffer via byte_width(), which is 0 for boolean
// (bit-packed), the same GH-45086 buffer-overflow pattern fixed elsewhere in this
// file. A chunk needs to be large enough to write past the buffer's small built-in
// padding to reliably reproduce the crash.
TEST_F(TestReplaceBoolean, ReplaceWithMaskChunkedArray) {
constexpr int64_t kChunkLength = 4096;
auto all_false = ConstantArrayGenerator::Boolean(kChunkLength, /*value=*/false);
auto all_true = ConstantArrayGenerator::Boolean(kChunkLength, /*value=*/true);
auto input = std::make_shared<ChunkedArray>(
ArrayVector{all_false, all_false, all_false}, boolean());
auto expected = std::make_shared<ChunkedArray>(
ArrayVector{all_true, all_true, all_true}, boolean());

this->Assert(ReplaceWithMask, Datum(input), this->mask_scalar(true),
this->scalar("true"), Datum(expected));
}

TEST_F(TestReplaceNull, ReplaceWithMask) {
std::vector<ReplaceWithMaskCase> cases = {
{this->array("[]"), this->mask_scalar(false), this->array("[]"), this->array("[]")},
Expand Down Expand Up @@ -1117,6 +1135,13 @@ class TestFillNullType : public TestReplaceKernel<NullType> {
std::shared_ptr<DataType> type() override { return default_type_instance<NullType>(); }
};

class TestFillNullBoolean : public TestReplaceKernel<BooleanType> {
protected:
std::shared_ptr<DataType> type() override {
return TypeTraits<BooleanType>::type_singleton();
}
};

TYPED_TEST_SUITE(TestFillNullNumeric, NumericBasedTypes);
TYPED_TEST_SUITE(TestFillNullDecimal, DecimalArrowTypes);
TYPED_TEST_SUITE(TestFillNullBinary, BaseBinaryArrowTypes);
Expand Down Expand Up @@ -2092,6 +2117,41 @@ TYPED_TEST(TestFillNullBinary, FillBackwardChunkedArray) {
R"(["qup"])", R"(["qup", "mnz"])"}));
}

// Regression test for GH-45086: FillNullForwardChunked/FillNullBackwardChunked
// size each output chunk's data buffer as `type->byte_width() * chunk->length()`.
// For BooleanType, byte_width() returns 0 (it is bit-packed, not byte-addressable),
// so the buffer was allocated with 0 bytes while the chunk's declared length stayed
// the same, and filling the chunk wrote past the end of the (near-)empty buffer.
// The corruption/crash only reliably manifests once a chunk is large enough to
// write past the buffer's small built-in padding, hence the large pad length here.
TEST_F(TestFillNullBoolean, FillNullForwardChunkedArray) {
constexpr int64_t kPadLength = 4096;
ASSERT_OK_AND_ASSIGN(auto null_pad, MakeArrayOfNull(boolean(), kPadLength));
auto all_true = ConstantArrayGenerator::Boolean(kPadLength, /*value=*/true);
auto single_true = ConstantArrayGenerator::Boolean(1, /*value=*/true);

auto input = std::make_shared<ChunkedArray>(
ArrayVector{null_pad, single_true, null_pad}, boolean());
auto expected = std::make_shared<ChunkedArray>(
ArrayVector{null_pad, single_true, all_true}, boolean());

this->AssertFillNullChunkedArray(FillNullForward, input, expected);
}

TEST_F(TestFillNullBoolean, FillNullBackwardChunkedArray) {
constexpr int64_t kPadLength = 4096;
ASSERT_OK_AND_ASSIGN(auto null_pad, MakeArrayOfNull(boolean(), kPadLength));
auto all_true = ConstantArrayGenerator::Boolean(kPadLength, /*value=*/true);
auto single_true = ConstantArrayGenerator::Boolean(1, /*value=*/true);

auto input = std::make_shared<ChunkedArray>(
ArrayVector{null_pad, single_true, null_pad}, boolean());
auto expected = std::make_shared<ChunkedArray>(
ArrayVector{all_true, single_true, null_pad}, boolean());

this->AssertFillNullChunkedArray(FillNullBackward, input, expected);
}

TEST_F(TestFillNullType, TestFillOnNullType) {
this->AssertFillNullArray(FillNullForward, this->array(R"([null, null, null, null])"),
this->array(R"([null, null, null, null])"));
Expand Down