ladybird/Tests/AK/TestUtf8.cpp
Ben Wiederhake ff8f3814cc AK+Tests: Avoid creating invalid code points from malformed UTF-8
Instead of doing anything reasonable, Utf8CodePointIterator returned
invalid code points, for example U+123456. However, many callers of this
iterator assume that a code point is always at most 0x10FFFF.

In fact, this is one of two reasons for the following OSS Fuzz issue:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=49184
This is probably a very old bug.

In the particular case of URLParser, AK::is_url_code_point got confused:
    return /* ... */ || code_point >= 0xA0;
If code_point is a "code point" beyond 0x10FFFF, this violates the
condition given in the preceding comment, but satisfies the given
condition, which eventually causes URLParser to crash.

This commit fixes *only* the erroneous UTF-8 decoding, and does not
fully resolve OSS-Fuzz#49184.
2022-10-09 10:37:20 -06:00

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/*
* Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibTest/TestCase.h>
#include <AK/ByteBuffer.h>
#include <AK/Utf8View.h>
TEST_CASE(decode_ascii)
{
Utf8View utf8 { "Hello World!11"sv };
EXPECT(utf8.validate());
u32 expected[] = { 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 49, 49 };
size_t expected_size = sizeof(expected) / sizeof(expected[0]);
size_t i = 0;
for (u32 code_point : utf8) {
VERIFY(i < expected_size);
EXPECT_EQ(code_point, expected[i]);
i++;
}
EXPECT_EQ(i, expected_size);
}
TEST_CASE(decode_utf8)
{
Utf8View utf8 { "Привет, мир! 😀 γειά σου κόσμος こんにちは世界"sv };
size_t valid_bytes;
EXPECT(utf8.validate(valid_bytes));
EXPECT(valid_bytes == (size_t)utf8.byte_length());
u32 expected[] = { 1055, 1088, 1080, 1074, 1077, 1090, 44, 32, 1084, 1080, 1088, 33, 32, 128512, 32, 947, 949, 953, 940, 32, 963, 959, 965, 32, 954, 972, 963, 956, 959, 962, 32, 12371, 12435, 12395, 12385, 12399, 19990, 30028 };
String expected_underlying_bytes[] = { "П", "р", "и", "в", "е", "т", ",", " ", "м", "и", "р", "!", " ", "😀", " ", "γ", "ε", "ι", "ά", " ", "σ", "ο", "υ", " ", "κ", "ό", "σ", "μ", "ο", "ς", " ", "", "", "", "", "", "", "" };
size_t expected_size = sizeof(expected) / sizeof(expected[0]);
size_t i = 0;
for (auto it = utf8.begin(); it != utf8.end(); ++it) {
u32 code_point = *it;
VERIFY(i < expected_size);
EXPECT_EQ(code_point, expected[i]);
EXPECT_EQ(it.underlying_code_point_bytes(), expected_underlying_bytes[i].bytes());
i++;
}
EXPECT_EQ(i, expected_size);
}
TEST_CASE(validate_invalid_ut8)
{
size_t valid_bytes;
char invalid_utf8_1[] = { 42, 35, (char)182, 9 };
Utf8View utf8_1 { StringView { invalid_utf8_1, 4 } };
EXPECT(!utf8_1.validate(valid_bytes));
EXPECT(valid_bytes == 2);
char invalid_utf8_2[] = { 42, 35, (char)208, (char)208 };
Utf8View utf8_2 { StringView { invalid_utf8_2, 4 } };
EXPECT(!utf8_2.validate(valid_bytes));
EXPECT(valid_bytes == 2);
char invalid_utf8_3[] = { (char)208 };
Utf8View utf8_3 { StringView { invalid_utf8_3, 1 } };
EXPECT(!utf8_3.validate(valid_bytes));
EXPECT(valid_bytes == 0);
char invalid_utf8_4[] = { (char)208, 35 };
Utf8View utf8_4 { StringView { invalid_utf8_4, 2 } };
EXPECT(!utf8_4.validate(valid_bytes));
EXPECT(valid_bytes == 0);
char invalid_utf8_5[] = { (char)0xf4, (char)0x8f, (char)0xbf, (char)0xc0 }; // U+110000
Utf8View utf8_5 { StringView { invalid_utf8_5, 4 } };
EXPECT(!utf8_5.validate(valid_bytes));
EXPECT(valid_bytes == 0);
char invalid_utf8_6[] = { (char)0xf4, (char)0xa1, (char)0xb0, (char)0xbd }; // U+121c3d
Utf8View utf8_6 { StringView { invalid_utf8_6, 4 } };
EXPECT(!utf8_6.validate(valid_bytes));
EXPECT(valid_bytes == 0);
}
TEST_CASE(iterate_utf8)
{
Utf8View view("Some weird characters \u00A9\u266A\uA755"sv);
Utf8CodePointIterator iterator = view.begin();
EXPECT(*iterator == 'S');
EXPECT(iterator.peek().has_value() && iterator.peek().value() == 'S');
EXPECT(iterator.peek(0).has_value() && iterator.peek(0).value() == 'S');
EXPECT(iterator.peek(1).has_value() && iterator.peek(1).value() == 'o');
EXPECT(iterator.peek(22).has_value() && iterator.peek(22).value() == 0x00A9);
EXPECT(iterator.peek(24).has_value() && iterator.peek(24).value() == 0xA755);
EXPECT(!iterator.peek(25).has_value());
++iterator;
EXPECT(*iterator == 'o');
EXPECT(iterator.peek(23).has_value() && iterator.peek(23).value() == 0xA755);
for (size_t i = 0; i < 23; ++i)
++iterator;
EXPECT(!iterator.done());
EXPECT(*iterator == 0xA755);
EXPECT(iterator.peek().has_value() && iterator.peek().value() == 0xA755);
EXPECT(!iterator.peek(1).has_value());
++iterator;
EXPECT(iterator.done());
EXPECT(!iterator.peek(0).has_value());
EXPECT_CRASH("Dereferencing Utf8CodePointIterator which is already done.", [&iterator] {
*iterator;
return Test::Crash::Failure::DidNotCrash;
});
}
TEST_CASE(decode_invalid_ut8)
{
// Test case 1 : Getting an extension byte as first byte of the code point
{
char raw_data[] = { 'a', 'b', (char)0xA0, 'd' };
Utf8View view { StringView { raw_data, 4 } };
u32 expected_characters[] = { 'a', 'b', 0xFFFD, 'd' };
String expected_underlying_bytes[] = { "a", "b", "\xA0", "d" };
size_t expected_size = sizeof(expected_characters) / sizeof(expected_characters[0]);
size_t i = 0;
for (auto it = view.begin(); it != view.end(); ++it) {
u32 code_point = *it;
VERIFY(i < expected_size);
EXPECT_EQ(code_point, expected_characters[i]);
EXPECT_EQ(it.underlying_code_point_bytes(), expected_underlying_bytes[i].bytes());
i++;
}
VERIFY(i == expected_size);
}
// Test case 2 : Getting a non-extension byte when an extension byte is expected
{
char raw_data[] = { 'a', 'b', (char)0xC0, 'd', 'e' };
Utf8View view { StringView { raw_data, 5 } };
u32 expected_characters[] = { 'a', 'b', 0xFFFD, 'd', 'e' };
String expected_underlying_bytes[] = { "a", "b", "\xC0", "d", "e" };
size_t expected_size = sizeof(expected_characters) / sizeof(expected_characters[0]);
size_t i = 0;
for (auto it = view.begin(); it != view.end(); ++it) {
u32 code_point = *it;
VERIFY(i < expected_size);
EXPECT_EQ(code_point, expected_characters[i]);
EXPECT_EQ(it.underlying_code_point_bytes(), expected_underlying_bytes[i].bytes());
i++;
}
VERIFY(i == expected_size);
}
// Test case 3 : Not enough bytes before the end of the string
{
char raw_data[] = { 'a', 'b', (char)0x90, 'd' };
Utf8View view { StringView { raw_data, 4 } };
u32 expected_characters[] = { 'a', 'b', 0xFFFD, 'd' };
String expected_underlying_bytes[] = { "a", "b", "\x90", "d" };
size_t expected_size = sizeof(expected_characters) / sizeof(expected_characters[0]);
size_t i = 0;
for (auto it = view.begin(); it != view.end(); ++it) {
u32 code_point = *it;
VERIFY(i < expected_size);
EXPECT_EQ(code_point, expected_characters[i]);
EXPECT_EQ(it.underlying_code_point_bytes(), expected_underlying_bytes[i].bytes());
i++;
}
VERIFY(i == expected_size);
}
// Test case 4 : Not enough bytes at the end of the string
{
char raw_data[] = { 'a', 'b', 'c', (char)0x90 };
Utf8View view { StringView { raw_data, 4 } };
u32 expected_characters[] = { 'a', 'b', 'c', 0xFFFD };
String expected_underlying_bytes[] = { "a", "b", "c", "\x90" };
size_t expected_size = sizeof(expected_characters) / sizeof(expected_characters[0]);
size_t i = 0;
for (auto it = view.begin(); it != view.end(); ++it) {
u32 code_point = *it;
VERIFY(i < expected_size);
EXPECT_EQ(code_point, expected_characters[i]);
EXPECT_EQ(it.underlying_code_point_bytes(), expected_underlying_bytes[i].bytes());
i++;
}
VERIFY(i == expected_size);
}
// Test case 5 : Oversized four-byte sequence (e.g. U+123456)
{
// Want to encode: (000)1 0010 0011 0100 0101 0110
// Into mask: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
// Shifted: 100 100011 010001 010110
// Result: 11110100 10100011 10010001 10010110
char raw_data[] = { 'a', (char)0xF4, (char)0xA3, (char)0x91, (char)0x96, 'b' };
Utf8View view { StringView { raw_data, 6 } };
// This definition seems to suggest that we should instead output multiple replacement characters:
// https://encoding.spec.whatwg.org/#ref-for-concept-stream-prepend②
// This is supported by the plaintext description and example collection, which annoyingly does not give an example of how to deal with this:
// https://www.unicode.org/versions/Unicode14.0.0/ch03.pdf , section "U+FFFD Substitution of Maximal Subparts"
// However, that would go against how we deal with several other kinds of errors, so we stick to emitting only one U+FFFD.
u32 expected_characters[] = { 'a', 0xFFFD, 'b' };
String expected_underlying_bytes[] = { "a", "\xF4\xA3\x91\x96", "b" };
size_t expected_size = sizeof(expected_characters) / sizeof(expected_characters[0]);
size_t i = 0;
for (auto it = view.begin(); it != view.end(); ++it) {
u32 code_point = *it;
VERIFY(i < expected_size);
EXPECT_EQ(code_point, expected_characters[i]);
EXPECT_EQ(it.underlying_code_point_bytes(), expected_underlying_bytes[i].bytes());
i++;
}
VERIFY(i == expected_size);
}
}
TEST_CASE(trim)
{
Utf8View whitespace { " "sv };
{
Utf8View view { "word"sv };
EXPECT_EQ(view.trim(whitespace, TrimMode::Both).as_string(), "word");
EXPECT_EQ(view.trim(whitespace, TrimMode::Left).as_string(), "word");
EXPECT_EQ(view.trim(whitespace, TrimMode::Right).as_string(), "word");
}
{
Utf8View view { " word"sv };
EXPECT_EQ(view.trim(whitespace, TrimMode::Both).as_string(), "word");
EXPECT_EQ(view.trim(whitespace, TrimMode::Left).as_string(), "word");
EXPECT_EQ(view.trim(whitespace, TrimMode::Right).as_string(), " word");
}
{
Utf8View view { "word "sv };
EXPECT_EQ(view.trim(whitespace, TrimMode::Both).as_string(), "word");
EXPECT_EQ(view.trim(whitespace, TrimMode::Left).as_string(), "word ");
EXPECT_EQ(view.trim(whitespace, TrimMode::Right).as_string(), "word");
}
{
Utf8View view { " word "sv };
EXPECT_EQ(view.trim(whitespace, TrimMode::Both).as_string(), "word");
EXPECT_EQ(view.trim(whitespace, TrimMode::Left).as_string(), "word ");
EXPECT_EQ(view.trim(whitespace, TrimMode::Right).as_string(), " word");
}
{
Utf8View view { "\u180E"sv };
EXPECT_EQ(view.trim(whitespace, TrimMode::Both).as_string(), "\u180E");
EXPECT_EQ(view.trim(whitespace, TrimMode::Left).as_string(), "\u180E");
EXPECT_EQ(view.trim(whitespace, TrimMode::Right).as_string(), "\u180E");
}
}