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libstdc++: Check for size overflow in constexpr allocation [PR105957]

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libstdc++-v3/ChangeLog:

	PR libstdc++/105957
	* include/bits/allocator.h (allocator::allocate): Check for
	overflow in constexpr allocation.
	* testsuite/20_util/allocator/105975.cc: New test.
This commit is contained in:
Jonathan Wakely 2022-06-14 14:37:25 +01:00
parent 3e16b4359e
commit 0a9af7b4ef
2 changed files with 24 additions and 1 deletions
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7
libstdc++-v3/include/bits/allocator.h
View file

@ -184,7 +184,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
allocate(size_t __n)
{
if (std::__is_constant_evaluated())
return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
{
if (__builtin_mul_overflow(__n, sizeof(_Tp), &__n))
std::__throw_bad_array_new_length();
return static_cast<_Tp*>(::operator new(__n));
}
return __allocator_base<_Tp>::allocate(__n, 0);
}

18
libstdc++-v3/testsuite/20_util/allocator/105975.cc Normal file
View file

@ -0,0 +1,18 @@
// { dg-options "-std=gnu++20" }
// { dg-do compile { target c++20 } }
// PR libstdc++/105957
#include <memory>
consteval bool test_pr105957()
{
std::allocator<long long> a;
auto n = std::size_t(-1) / (sizeof(long long) - 1);
auto p = a.allocate(n); // { dg-error "constexpr" }
a.deallocate(p, n);
return true;
}
static_assert( test_pr105957() );
// { dg-error "throw_bad_array_new_length" "" { target *-*-* } 0 }