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AK: Check for overflow in StringUtils::convert_to_int

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Sahan Fernando 2020-12-20 16:27:33 +11:00 committed by Andreas Kling
parent 37df4bbd90
commit f469f44cc6
1 changed files with 18 additions and 7 deletions
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25
AK/StringUtils.cpp
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@ -103,7 +103,7 @@ Optional<T> convert_to_int(const StringView& str)
if (str_trimmed.is_empty())
return {};
bool negative = false;
T sign = 1;
size_t i = 0;
const auto characters = str_trimmed.characters_without_null_termination();
@ -111,17 +111,22 @@ Optional<T> convert_to_int(const StringView& str)
if (str_trimmed.length() == 1)
return {};
i++;
negative = (characters[0] == '-');
if (characters[0] == '-')
sign = -1;
}
T value = 0;
for (; i < str_trimmed.length(); i++) {
if (characters[i] < '0' || characters[i] > '9')
return {};
value = value * 10;
value += characters[i] - '0';
if (__builtin_mul_overflow(value, 10, &value))
return {};
if (__builtin_add_overflow(value, sign * (characters[i] - '0'), &value))
return {};
}
return negative ? -value : value;
return value;
}
template Optional<i8> convert_to_int(const StringView& str);
@ -143,8 +148,11 @@ Optional<T> convert_to_uint(const StringView& str)
if (characters[i] < '0' || characters[i] > '9')
return {};
value = value * 10;
value += characters[i] - '0';
if (__builtin_mul_overflow(value, 10, &value))
return {};
if (__builtin_add_overflow(value, characters[i] - '0', &value))
return {};
}
return value;
}
@ -163,10 +171,13 @@ Optional<T> convert_to_uint_from_hex(const StringView& str)
T value = 0;
const auto count = str_trimmed.length();
const T upper_bound = AK::NumericLimits<T>::max();
for (size_t i = 0; i < count; i++) {
char digit = str_trimmed[i];
u8 digit_val;
if (value > (upper_bound >> 4))
return {};
if (digit >= '0' && digit <= '9') {
digit_val = digit - '0';