From 5fc6a6973ac844af909e101de69a1e944a9e53b7 Mon Sep 17 00:00:00 2001
From: dmitry kuzmin <corax@list.ru>
Date: Thu, 13 Jun 2019 23:28:14 +0300
Subject: [PATCH] float to decimal overflow fix

---
 dbms/src/DataTypes/DataTypesDecimal.h         | 21 ++++++++++---------
 .../0_stateless/00700_decimal_casts.sql       |  4 ++++
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/dbms/src/DataTypes/DataTypesDecimal.h b/dbms/src/DataTypes/DataTypesDecimal.h
index 49f00aafa9c..ea0d777784d 100644
--- a/dbms/src/DataTypes/DataTypesDecimal.h
+++ b/dbms/src/DataTypes/DataTypesDecimal.h
@@ -324,22 +324,23 @@ convertToDecimal(const typename FromDataType::FieldType & value, UInt32 scale)
 
     if constexpr (std::is_floating_point_v<FromFieldType>)
     {
-        ToNativeType min_value;
-        ToNativeType max_value;
+        if (!std::isfinite(value))
+            throw Exception("Decimal convert overflow. Cannot convert infinity or NaN to decimal", ErrorCodes::DECIMAL_OVERFLOW);
+
+        auto out = value * ToDataType::getScaleMultiplier(scale);
         if constexpr (std::is_same_v<ToNativeType, Int128>)
         {
-            min_value = __int128(0x8000000000000000ll) << 64; // min __int128
-            max_value = (__int128(0x7fffffffffffffffll) << 64) + 0xffffffffffffffffll; // max __int128
+            static constexpr __int128 min_int128 = __int128(0x8000000000000000ll) << 64;
+            static constexpr __int128 max_int128 = (__int128(0x7fffffffffffffffll) << 64) + 0xffffffffffffffffll;
+            if (out < min_int128 || out > max_int128)
+                throw Exception("Decimal convert overflow. Float is out of Decimal range", ErrorCodes::DECIMAL_OVERFLOW);
         }
         else
         {
-            min_value = std::numeric_limits<ToNativeType>::min();
-            max_value = std::numeric_limits<ToNativeType>::max();
+            if (out < std::numeric_limits<ToNativeType>::min() || out > std::numeric_limits<ToNativeType>::max())
+                throw Exception("Decimal convert overflow. Float is out of Decimal range", ErrorCodes::DECIMAL_OVERFLOW);
         }
-        ToNativeType converted_value = static_cast<ToNativeType>(value * ToDataType::getScaleMultiplier(scale));
-        if (converted_value == min_value || converted_value == max_value)
-            throw Exception("Decimal convert overflow", ErrorCodes::DECIMAL_OVERFLOW);
-        return converted_value;
+        return out;
     }
     else
     {
diff --git a/dbms/tests/queries/0_stateless/00700_decimal_casts.sql b/dbms/tests/queries/0_stateless/00700_decimal_casts.sql
index 5c7de179624..bc32f5b19fc 100644
--- a/dbms/tests/queries/0_stateless/00700_decimal_casts.sql
+++ b/dbms/tests/queries/0_stateless/00700_decimal_casts.sql
@@ -254,3 +254,7 @@ SELECT CAST(0/0, 'Decimal(38, 5)'); -- { serverError 407 }
 select toDecimal32(10000.1, 6); -- { serverError 407 }
 select toDecimal64(10000.1, 18); -- { serverError 407 }
 select toDecimal128(1000000000000000000000.1, 18); -- { serverError 407 }
+
+select toDecimal32(-10000.1, 6); -- { serverError 407 }
+select toDecimal64(-10000.1, 18); -- { serverError 407 }
+select toDecimal128(-1000000000000000000000.1, 18); -- { serverError 407 }