On Mon, Sep 14, 2020 at 5:52 AM Ville Voutilainen wrote: > On Mon, 14 Sep 2020 at 12:51, Ville Voutilainen > wrote: > > On Mon, 14 Sep 2020 at 09:18, Glen Fernandes > wrote: > > > Edit; Correct patch this time. > > > > > > Fix overflow handling in align > > > > Should the test verify that space is unmodified when nullptr is returned? > > ..and same for ptr.
Sounds like a good idea. Updated patch attached. Glen
commit 5ebb97628f888bbc8e6617f2a7eea83aa40c1f37 Author: Glen Joseph Fernandes <glenj...@gmail.com> Date: Mon Sep 14 01:21:27 2020 -0400 Fix overflow handling in align 2020-09-12 Glen Joseph Fernandes <glenj...@gmail.com> * include/bits/align.h (align): Fix overflow handling. * testsuite/20_util/align/3.cc: New tests. diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 0878f31562e..e25770ce5ca 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,8 @@ +2020-09-12 Glen Joseph Fernandes <glenj...@gmail.com> + + * include/bits/align.h (align): Fix overflow handling. + * testsuite/20_util/align/3.cc: New tests. + 2020-09-11 Thomas Rodgers <trodg...@redhat.com> * include/std/memory: Move #include <bits/align.h> inside C++11 diff --git a/libstdc++-v3/include/bits/align.h b/libstdc++-v3/include/bits/align.h index c3267f22934..b9b81fd785d 100644 --- a/libstdc++-v3/include/bits/align.h +++ b/libstdc++-v3/include/bits/align.h @@ -60,6 +60,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION inline void* align(size_t __align, size_t __size, void*& __ptr, size_t& __space) noexcept { + if (__space < __size) + return nullptr; #ifdef _GLIBCXX_USE_C99_STDINT_TR1 const auto __intptr = reinterpret_cast<uintptr_t>(__ptr); #else @@ -70,7 +72,7 @@ align(size_t __align, size_t __size, void*& __ptr, size_t& __space) noexcept #endif const auto __aligned = (__intptr - 1u + __align) & -__align; const auto __diff = __aligned - __intptr; - if ((__size + __diff) > __space) + if (!(__diff <= (__space - __size))) return nullptr; else { diff --git a/libstdc++-v3/testsuite/20_util/align/3.cc b/libstdc++-v3/testsuite/20_util/align/3.cc new file mode 100644 index 00000000000..39bff3472ce --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/align/3.cc @@ -0,0 +1,53 @@ +// { dg-do run { target c++11 } } + +// 2020-09-12 Glen Joseph Fernandes <glenj...@gmail.com> + +// Copyright (C) 2020 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the terms +// of the GNU General Public License as published by the Free Software +// Foundation; either version 3, or (at your option) any later +// version. + +// This library is distributed in the hope that it will be useful, but +// WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +// C++11 [ptr.align] (20.6.5): std::align + +#include <memory> +#include <testsuite_hooks.h> + +void test01() +{ + void* p1 = reinterpret_cast<void*>(5); + void* p2 = p1; + std::size_t s1 = 3072; + std::size_t s2 = s1; + VERIFY(std::align(1024, static_cast<std::size_t>(-1), p1, s1) == nullptr); + VERIFY(p1 == p2); + VERIFY(s1 == s2); +} + +void test02() +{ + void* p1 = reinterpret_cast<void*>(1); + void* p2 = p1; + std::size_t s1 = -1; + std::size_t s2 = s1; + VERIFY(std::align(2, static_cast<std::size_t>(-1), p1, s1) == nullptr); + VERIFY(p1 == p2); + VERIFY(s1 == s2); +} + +int main() +{ + test01(); + test02(); +}