From b69191bbb2278fce92b470e8e3abafe048166e39 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= Date: Fri, 18 Feb 2022 16:31:54 +0200 Subject: [PATCH] MDEV-26645: Fix UB in Item_func_plus and Item_func_minus An integer overflow in an expression like a+b or a-b is undefined behavior. The compiler is allowed to assume that no such overflow is possible, and optimize away some code accordingly. Item_func_plus::int_op(), Item_func_minus::int_op(): Always check for overflow. Depending on the compiler and the compilation options, a test might fail: CURRENT_TEST: main.func_math mysqltest: At line 425: query 'SELECT 9223372036854775807 + 9223372036854775807' succeeded - should have failed with errno 1690... A similar bug had been fixed earlier in commit 328edf8560dbf1941ce314fa112e0db05d9f97f1. --- sql/item_func.cc | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) diff --git a/sql/item_func.cc b/sql/item_func.cc index 60efc55d8785c..452bc74cc8215 100644 --- a/sql/item_func.cc +++ b/sql/item_func.cc @@ -1,5 +1,5 @@ /* Copyright (c) 2000, 2015, Oracle and/or its affiliates. - Copyright (c) 2009, 2021, MariaDB + Copyright (c) 2009, 2022, MariaDB This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -1163,14 +1163,10 @@ longlong Item_func_plus::int_op() } } -#ifndef WITH_UBSAN - res= val0 + val1; -#else if (res_unsigned) res= (longlong) ((ulonglong) val0 + (ulonglong) val1); else - res= val0+val1; -#endif /* WITH_UBSAN */ + res= val0 + val1; return check_integer_overflow(res, res_unsigned); @@ -1333,14 +1329,10 @@ longlong Item_func_minus::int_op() goto err; } } -#ifndef WITH_UBSAN - res= val0 - val1; -#else if (res_unsigned) res= (longlong) ((ulonglong) val0 - (ulonglong) val1); else res= val0 - val1; -#endif /* WITH_UBSAN */ return check_integer_overflow(res, res_unsigned);