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Check we don't overflow when casting down integers during parsing #4353

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Check we don't overflow when casting down integers during parsing #4353

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da5800c
Check we don't overflow when casting down integers during parsing
ArnaudBienner Apr 19, 2024
bd9d0b5
* Fix check
ArnaudBienner Apr 20, 2024
d2f1d90
Use std::isinf
ArnaudBienner Apr 20, 2024
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40 changes: 34 additions & 6 deletions include/nlohmann/detail/conversions/from_json.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,34 @@ inline void from_json(const BasicJsonType& j, typename std::nullptr_t& n)
n = nullptr;
}

template <typename BasicJsonType, typename ArithmeticTypeTarget, typename ArithmeticTypeSource>
ArithmeticTypeTarget static_cast_check_range(const BasicJsonType& j)
{
const ArithmeticTypeSource val = *j.template get_ptr<ArithmeticTypeSource*>();
if constexpr (sizeof(ArithmeticTypeTarget) < sizeof(ArithmeticTypeSource) || std::is_floating_point<ArithmeticTypeSource>::value)
{
const ArithmeticTypeSource min =
std::is_signed<ArithmeticTypeSource>::value ? std::numeric_limits<ArithmeticTypeTarget>::lowest() : 0;
const ArithmeticTypeSource max = std::numeric_limits<ArithmeticTypeTarget>::max();
bool valIsInf = false;
if constexpr (std::is_floating_point<ArithmeticTypeSource>::value)
{
valIsInf = std::isinf(val);
}
if ((val < min || val > max) && !valIsInf)
{
JSON_THROW(
out_of_range::create(
406,
"value " + std::to_string(val) + " is out of target integer range [" +
std::to_string(std::numeric_limits<ArithmeticTypeTarget>::lowest()) + ", " +
std::to_string(std::numeric_limits<ArithmeticTypeTarget>::max()) + "]", &j));
}
}
return static_cast<ArithmeticTypeTarget>(val);
}


// overloads for basic_json template parameters
template < typename BasicJsonType, typename ArithmeticType,
enable_if_t < std::is_arithmetic<ArithmeticType>::value&&
Expand All @@ -54,17 +82,17 @@ void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
{
case value_t::number_unsigned:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
val = static_cast_check_range<BasicJsonType, ArithmeticType, const typename BasicJsonType::number_unsigned_t>(j);
break;
}
case value_t::number_integer:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
val = static_cast_check_range<BasicJsonType, ArithmeticType, const typename BasicJsonType::number_integer_t>(j);
break;
}
case value_t::number_float:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
val = static_cast_check_range<BasicJsonType, ArithmeticType, const typename BasicJsonType::number_float_t>(j);
break;
}

Expand Down Expand Up @@ -343,17 +371,17 @@ inline void from_json(const BasicJsonType& j, ArithmeticType& val)
{
case value_t::number_unsigned:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
val = static_cast_check_range<BasicJsonType, ArithmeticType, const typename BasicJsonType::number_unsigned_t>(j);
break;
}
case value_t::number_integer:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
val = static_cast_check_range<BasicJsonType, ArithmeticType, const typename BasicJsonType::number_integer_t>(j);
break;
}
case value_t::number_float:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
val = static_cast_check_range<BasicJsonType, ArithmeticType, const typename BasicJsonType::number_float_t>(j);
break;
}
case value_t::boolean:
Expand Down
9 changes: 9 additions & 0 deletions tests/src/unit-class_parser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -585,6 +585,15 @@ TEST_CASE("parser class")
CHECK_THROWS_WITH_AS(parser_helper("1.18973e+4932").empty(), "[json.exception.out_of_range.406] number overflow parsing '1.18973e+4932'", json::out_of_range&);
}

SECTION("out-of-range-conversion")
{
// overflows during parsing with casting yield an exception
CHECK_THROWS_WITH_AS(parser_helper("123456").get<int16_t>(), "[json.exception.out_of_range.406] value 123456 is out of target integer range [-32768, 32767]", json::out_of_range&);
CHECK_THROWS_WITH_AS(parser_helper("65536").get<int16_t>(), "[json.exception.out_of_range.406] value 65536 is out of target integer range [-32768, 32767]", json::out_of_range&);
CHECK_THROWS_WITH_AS(parser_helper("-32769").get<int16_t>(), "[json.exception.out_of_range.406] value -32769 is out of target integer range [-32768, 32767]", json::out_of_range&);
CHECK_THROWS_WITH_AS(parser_helper("18446744073709559808").get<uint64_t>(), "[json.exception.out_of_range.406] value 18446744073709559808.000000 is out of target integer range [0, 18446744073709551615]", json::out_of_range&);
}

SECTION("invalid numbers")
{
// numbers must not begin with "+"
Expand Down