From a70637ab4b3df7af6e3e1f9795c2a3f102978e42 Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@yandex-team.ru>
Date: Sun, 26 Apr 2020 17:57:45 +0300
Subject: [PATCH] Fixed UBSan; added a test

---
 src/Core/DecimalFunctions.h                   | 42 ++++++++++++-------
 .../01259_datetime64_ubsan.reference          |  1 +
 .../0_stateless/01259_datetime64_ubsan.sql    |  2 +
 3 files changed, 30 insertions(+), 15 deletions(-)
 create mode 100644 tests/queries/0_stateless/01259_datetime64_ubsan.reference
 create mode 100644 tests/queries/0_stateless/01259_datetime64_ubsan.sql

diff --git a/src/Core/DecimalFunctions.h b/src/Core/DecimalFunctions.h
index f098f2427eb..d8fdccf8628 100644
--- a/src/Core/DecimalFunctions.h
+++ b/src/Core/DecimalFunctions.h
@@ -2,15 +2,20 @@
 // Moved Decimal-related functions out from Core/Types.h to reduce compilation time.
 
 #include <Core/Types.h>
-#include <Common/intExp.h>
+#include <Common/Exception.h>
+#include <common/arithmeticOverflow.h>
 
 #include <limits>
 
-class DateLUTImpl;
 
 namespace DB
 {
 
+namespace ErrorCodes
+{
+    extern const int DECIMAL_OVERFLOW;
+}
+
 namespace DecimalUtils
 {
 
@@ -37,22 +42,26 @@ struct DecimalComponents
 };
 
 /** Make a decimal value from whole and fractional components with given scale multiplier.
- * where scale_multiplier = scaleMultiplier<T>(scale)
- * this is to reduce number of calls to scaleMultiplier when scale is known.
- *
- * Sign of `whole` controls sign of result: negative whole => negative result, positive whole => positive result.
- * Sign of `fractional` is expected to be positive, otherwise result is undefined.
- * If `scale` is to big (scale > maxPrecision<DecimalType::NativeType>), result is undefined.
- */
+  * where scale_multiplier = scaleMultiplier<T>(scale)
+  * this is to reduce number of calls to scaleMultiplier when scale is known.
+  *
+  * Sign of `whole` controls sign of result: negative whole => negative result, positive whole => positive result.
+  * Sign of `fractional` is expected to be positive, otherwise result is undefined.
+  * If `scale` is to big (scale > maxPrecision<DecimalType::NativeType>), result is undefined.
+  */
 template <typename DecimalType>
 DecimalType decimalFromComponentsWithMultiplier(const typename DecimalType::NativeType & whole,
-                                                 const typename DecimalType::NativeType & fractional,
-                                                 typename DecimalType::NativeType scale_multiplier)
+                                                const typename DecimalType::NativeType & fractional,
+                                                typename DecimalType::NativeType scale_multiplier)
 {
     using T = typename DecimalType::NativeType;
     const auto fractional_sign = whole < 0 ? -1 : 1;
 
-    const T value = whole * scale_multiplier + fractional_sign * (fractional % scale_multiplier);
+    T whole_scaled = 0;
+    if (common::mulOverflow(whole, scale_multiplier, whole_scaled))
+        throw Exception("Decimal math overflow", ErrorCodes::DECIMAL_OVERFLOW);
+
+    const T value = whole_scaled + fractional_sign * (fractional % scale_multiplier);
     return DecimalType(value);
 }
 
@@ -61,7 +70,8 @@ DecimalType decimalFromComponentsWithMultiplier(const typename DecimalType::Nati
  * @see `decimalFromComponentsWithMultiplier` for details.
  */
 template <typename DecimalType>
-DecimalType decimalFromComponents(const typename DecimalType::NativeType & whole, const typename DecimalType::NativeType & fractional, UInt32 scale)
+DecimalType decimalFromComponents(
+    const typename DecimalType::NativeType & whole, const typename DecimalType::NativeType & fractional, UInt32 scale)
 {
     using T = typename DecimalType::NativeType;
 
@@ -72,7 +82,8 @@ DecimalType decimalFromComponents(const typename DecimalType::NativeType & whole
  * @see `decimalFromComponentsWithMultiplier` for details.
  */
 template <typename DecimalType>
-DecimalType decimalFromComponents(const DecimalComponents<typename DecimalType::NativeType> & components, UInt32 scale)
+DecimalType decimalFromComponents(
+    const DecimalComponents<typename DecimalType::NativeType> & components, UInt32 scale)
 {
     return decimalFromComponents<DecimalType>(components.whole, components.fractional, scale);
 }
@@ -81,7 +92,8 @@ DecimalType decimalFromComponents(const DecimalComponents<typename DecimalType::
  * This is an optimization to reduce number of calls to scaleMultiplier on known scale.
  */
 template <typename DecimalType>
-DecimalComponents<typename DecimalType::NativeType> splitWithScaleMultiplier(const DecimalType & decimal, typename DecimalType::NativeType scale_multiplier)
+DecimalComponents<typename DecimalType::NativeType> splitWithScaleMultiplier(
+    const DecimalType & decimal, typename DecimalType::NativeType scale_multiplier)
 {
     using T = typename DecimalType::NativeType;
     const auto whole = decimal.value / scale_multiplier;
diff --git a/tests/queries/0_stateless/01259_datetime64_ubsan.reference b/tests/queries/0_stateless/01259_datetime64_ubsan.reference
new file mode 100644
index 00000000000..f04c001f3f7
--- /dev/null
+++ b/tests/queries/0_stateless/01259_datetime64_ubsan.reference
@@ -0,0 +1 @@
+29
diff --git a/tests/queries/0_stateless/01259_datetime64_ubsan.sql b/tests/queries/0_stateless/01259_datetime64_ubsan.sql
new file mode 100644
index 00000000000..3cba78c713f
--- /dev/null
+++ b/tests/queries/0_stateless/01259_datetime64_ubsan.sql
@@ -0,0 +1,2 @@
+select now64(10); -- { serverError 407 }
+select length(toString(now64(9)));