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/*
* Open Chinese Convert
*
* Copyright 2015 Carbo Kuo <byvoid@byvoid.com>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "Conversion.hpp"
#include "DictGroupTestBase.hpp"
namespace opencc {
class ConversionTest : public DictGroupTestBase {
protected:
ConversionTest()
: input(utf8("太后的头发干燥")), expected(utf8("太后的頭髮乾燥")) {}
virtual void SetUp() {
dict = CreateDictGroupForConversion();
conversion = ConversionPtr(new Conversion(dict));
}
DictPtr dict;
ConversionPtr conversion;
const std::string input;
const std::string expected;
};
TEST_F(ConversionTest, ConvertString) {
const std::string converted = conversion->Convert(input);
EXPECT_EQ(expected, converted);
}
TEST_F(ConversionTest, ConvertCString) {
const std::string converted = conversion->Convert(input.c_str());
EXPECT_EQ(expected, converted);
}
TEST_F(ConversionTest, TruncatedUtf8Sequence) {
// This test specifically triggers the information disclosure vulnerability
// in the old code. The bug occurs when a string ends with an incomplete
// UTF-8 sequence.
//
// Background: UTF8Util::NextCharLength() examines only the first byte to
// determine the expected character length (1-6 bytes), but doesn't verify
// that enough bytes actually remain before the null terminator.
//
// Trigger condition: When the expected UTF-8 character length exceeds
// the actual remaining bytes before null, the old code would:
// 1. Call FromSubstr with a length crossing the null terminator
// 2. Advance pstr beyond the null terminator
// 3. Continue reading heap memory on next iteration
// 4. Output leaked heap data to conversion result (INFORMATION DISCLOSURE)
// Construct a string ending with a truncated 3-byte UTF-8 sequence:
// - Normal text: "干" (valid 3-byte UTF-8: 0xE5 0xB9 0xB2)
// - Followed by: 0xE5 0xB9 (incomplete 3-byte sequence - missing last byte)
std::string malformed;
malformed += utf8("干"); // Valid character
malformed += '\xE5'; // Start of 3-byte UTF-8 (NextCharLength returns 3)
malformed += '\xB9'; // Second byte
// Missing third byte - only 2 bytes remain but NextCharLength expects 3
// Old code would jump over null, read heap memory, and leak it in output
// The fixed code should handle this gracefully without information disclosure
EXPECT_NO_THROW({
const std::string converted = conversion->Convert(malformed);
// Should convert "干" to "幹" (first candidate in dict) and preserve incomplete sequence
std::string expected;
expected += utf8("幹"); // Converted from "干" (dict has ["幹", "乾", "干"])
expected += '\xE5'; // Incomplete sequence preserved as-is
expected += '\xB9';
EXPECT_EQ(expected, converted);
// Should NOT contain garbage heap data beyond the input
// (ASan would catch any out-of-bounds reads during conversion)
});
}
} // namespace opencc