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Merged
frankslin merged 2 commits into from
Jul 1, 2026
Merged

Improve memory safety in DartsDict #1382

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5c8bb2c
Improve memory safety in DartsDict
frankslin Jul 1, 2026
72c28df
Add back comments about unit size detection logic
frankslin Jul 1, 2026
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110 changes: 64 additions & 46 deletions src/DartsDict.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
#include <algorithm>
#include <cstdint>
#include <cstring>
#include <memory>

#include "BinaryDict.hpp"
#include "DartsDict.hpp"
Expand Down Expand Up @@ -214,14 +215,12 @@ PrefixMatchView DartsDict::MatchPrefixValue(const char* word,

DartsDictPtr DartsDict::NewFromFile(FILE* fp) {
DartsDictPtr dict(new DartsDict());
auto internal = dict->internal;

size_t headerLen = strlen(OCDHEADER);
void* headerBuf = malloc(sizeof(char) * headerLen);
size_t bytesRead = fread(headerBuf, sizeof(char), headerLen, fp);
bool headerOk =
(bytesRead == headerLen) && (memcmp(headerBuf, OCDHEADER, headerLen) == 0);
free(headerBuf);
if (!headerOk) {
std::vector<char> headerBuffer(headerLen);
size_t bytesRead = fread(headerBuffer.data(), sizeof(char), headerLen, fp);
if (bytesRead != headerLen || memcmp(headerBuffer.data(), OCDHEADER, headerLen) != 0) {
throw InvalidFormat("Invalid OpenCC dictionary header");
}

Expand Down Expand Up @@ -249,8 +248,6 @@ DartsDictPtr DartsDict::NewFromFile(FILE* fp) {
bool is64bit =
(probe[4] == 0 && probe[5] == 0 && probe[6] == 0 && probe[7] == 0);

auto internal = dict->internal;

if (is64bit) {
uint64_t dartsSize64;
memcpy(&dartsSize64, probe, 8);
Expand All @@ -262,15 +259,21 @@ DartsDictPtr DartsDict::NewFromFile(FILE* fp) {
if (dartsSize % sizeof(LegacyUnit64) != 0) {
throw InvalidFormat("Invalid legacy OCD dictionary unit alignment");
}
void* buffer = malloc(dartsSize);
bytesRead = fread(buffer, 1, dartsSize, fp);
std::unique_ptr<void, decltype(&free)> buffer(malloc(dartsSize), free);
if (!buffer) {
throw std::bad_alloc();
}
bytesRead = fread(buffer.get(), 1, dartsSize, fp);
if (bytesRead != dartsSize) {
free(buffer);
throw InvalidFormat("Invalid legacy OCD dictionary size mismatch");
}
internal->buffer = buffer;
internal->binary = BinaryDict::NewFromFile(fp);
internal->legacyArray64 = static_cast<const LegacyUnit64*>(buffer);

BinaryDictPtr binary = BinaryDict::NewFromFile(fp);

internal->buffer = buffer.release();
internal->binary = std::move(binary);
internal->legacyArray64 = static_cast<const LegacyUnit64*>(internal->buffer);

dict->lexicon = internal->binary->GetLexicon();
dict->maxLength = internal->binary->KeyMaxLength();
size_t numUnits = dartsSize / sizeof(LegacyUnit64);
Expand All @@ -291,25 +294,29 @@ DartsDictPtr DartsDict::NewFromFile(FILE* fp) {
throw InvalidFormat(
"Invalid OpenCC dictionary (dartsSize exceeds file size)");
}
Darts::DoubleArray* doubleArray = new Darts::DoubleArray();
std::unique_ptr<Darts::DoubleArray> doubleArray(new Darts::DoubleArray());
if (dartsSize % doubleArray->unit_size() != 0) {
delete doubleArray;
throw InvalidFormat("Invalid OpenCC dictionary size of darts alignment");
}
void* buffer = malloc(dartsSize);
bytesRead = fread(buffer, 1, dartsSize, fp);
std::unique_ptr<void, decltype(&free)> buffer(malloc(dartsSize), free);
if (!buffer) {
throw std::bad_alloc();
}
bytesRead = fread(buffer.get(), 1, dartsSize, fp);
if (bytesRead != dartsSize) {
delete doubleArray;
free(buffer);
throw InvalidFormat("Invalid OpenCC dictionary size of darts mismatch");
}
doubleArray->set_array(buffer, dartsSize / doubleArray->unit_size());
internal->buffer = buffer;
internal->binary = BinaryDict::NewFromFile(fp);
internal->doubleArray = doubleArray;
doubleArray->set_array(buffer.get(), dartsSize / doubleArray->unit_size());

BinaryDictPtr binary = BinaryDict::NewFromFile(fp);

internal->buffer = buffer.release();
internal->doubleArray = doubleArray.release();
internal->binary = std::move(binary);

dict->lexicon = internal->binary->GetLexicon();
dict->maxLength = internal->binary->KeyMaxLength();
if (!doubleArray->validate(static_cast<Darts::DoubleArray::value_type>(
if (!internal->doubleArray->validate(static_cast<Darts::DoubleArray::value_type>(
dict->lexicon->Length()))) {
throw InvalidFormat("Invalid OpenCC dictionary darts data");
}
Expand All @@ -318,6 +325,7 @@ DartsDictPtr DartsDict::NewFromFile(FILE* fp) {

DartsDictPtr DartsDict::NewFromBuffer(const char* data, size_t size) {
DartsDictPtr dict(new DartsDict());
auto internal = dict->internal;

size_t headerLen = strlen(OCDHEADER);
if (size < headerLen || memcmp(data, OCDHEADER, headerLen) != 0) {
Expand All @@ -334,8 +342,6 @@ DartsDictPtr DartsDict::NewFromBuffer(const char* data, size_t size) {
bool is64bit =
(probe[4] == 0 && probe[5] == 0 && probe[6] == 0 && probe[7] == 0);

auto internal = dict->internal;

if (is64bit) {
uint64_t dartsSize64;
memcpy(&dartsSize64, probe, 8);
Expand All @@ -347,12 +353,19 @@ DartsDictPtr DartsDict::NewFromBuffer(const char* data, size_t size) {
if (dartsSize % sizeof(LegacyUnit64) != 0) {
throw InvalidFormat("Invalid legacy OCD dictionary unit alignment");
}
void* buffer = malloc(dartsSize);
memcpy(buffer, data + offset, dartsSize);
std::unique_ptr<void, decltype(&free)> buffer(malloc(dartsSize), free);
if (!buffer) {
throw std::bad_alloc();
}
memcpy(buffer.get(), data + offset, dartsSize);
offset += dartsSize;
internal->buffer = buffer;
internal->binary = BinaryDict::NewFromBuffer(data + offset, size - offset);
internal->legacyArray64 = static_cast<const LegacyUnit64*>(buffer);

BinaryDictPtr binary = BinaryDict::NewFromBuffer(data + offset, size - offset);

internal->buffer = buffer.release();
internal->binary = std::move(binary);
internal->legacyArray64 = static_cast<const LegacyUnit64*>(internal->buffer);

dict->lexicon = internal->binary->GetLexicon();
dict->maxLength = internal->binary->KeyMaxLength();
size_t numUnits = dartsSize / sizeof(LegacyUnit64);
Expand All @@ -363,8 +376,7 @@ DartsDictPtr DartsDict::NewFromBuffer(const char* data, size_t size) {
return dict;
}

// 32-bit: dartsSize is the first 4 bytes of probe; probe[4..7] belong to the
// darts array, so rewind 4 bytes before reading the array.
// 32-bit:
uint32_t dartsSize32;
memcpy(&dartsSize32, probe, 4);
size_t dartsSize = dartsSize32;
Expand All @@ -373,21 +385,27 @@ DartsDictPtr DartsDict::NewFromBuffer(const char* data, size_t size) {
throw InvalidFormat(
"Invalid OpenCC dictionary (dartsSize exceeds file size)");
}
Darts::DoubleArray* doubleArray = new Darts::DoubleArray();
std::unique_ptr<Darts::DoubleArray> doubleArray(new Darts::DoubleArray());
if (dartsSize % doubleArray->unit_size() != 0) {
delete doubleArray;
throw InvalidFormat("Invalid OpenCC dictionary size of darts alignment");
}
void* buffer = malloc(dartsSize);
memcpy(buffer, data + offset, dartsSize);
std::unique_ptr<void, decltype(&free)> buffer(malloc(dartsSize), free);
if (!buffer) {
throw std::bad_alloc();
}
memcpy(buffer.get(), data + offset, dartsSize);
offset += dartsSize;
doubleArray->set_array(buffer, dartsSize / doubleArray->unit_size());
internal->buffer = buffer;
internal->binary = BinaryDict::NewFromBuffer(data + offset, size - offset);
internal->doubleArray = doubleArray;
doubleArray->set_array(buffer.get(), dartsSize / doubleArray->unit_size());

BinaryDictPtr binary = BinaryDict::NewFromBuffer(data + offset, size - offset);

internal->buffer = buffer.release();
internal->doubleArray = doubleArray.release();
internal->binary = std::move(binary);

dict->lexicon = internal->binary->GetLexicon();
dict->maxLength = internal->binary->KeyMaxLength();
if (!doubleArray->validate(static_cast<Darts::DoubleArray::value_type>(
if (!internal->doubleArray->validate(static_cast<Darts::DoubleArray::value_type>(
dict->lexicon->Length()))) {
throw InvalidFormat("Invalid OpenCC dictionary darts data");
}
Expand All @@ -396,8 +414,9 @@ DartsDictPtr DartsDict::NewFromBuffer(const char* data, size_t size) {

DartsDictPtr DartsDict::NewFromDict(const Dict& thatDict) {
DartsDictPtr dict(new DartsDict());
auto internal = dict->internal;

Darts::DoubleArray* doubleArray = new Darts::DoubleArray();
std::unique_ptr<Darts::DoubleArray> doubleArray(new Darts::DoubleArray());
std::vector<std::string> keys;
std::vector<const char*> keys_cstr;
size_t maxLength = 0;
Expand All @@ -414,8 +433,7 @@ DartsDictPtr DartsDict::NewFromDict(const Dict& thatDict) {
doubleArray->build(lexicon->Length(), &keys_cstr[0]);
dict->lexicon = lexicon;
dict->maxLength = maxLength;
auto internal = dict->internal;
internal->doubleArray = doubleArray;
internal->doubleArray = doubleArray.release();
return dict;
}

Expand Down
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