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[libc++][hardening] Constrain construction for __{(static_)bounded,wrap}_iter (#115271)

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This PR restricts construction to cases where reference types of
source/destination iterators are (`T&`, `T&`) or (`T&`, `const T&`) (
where `T` can be const).

Fixes #50058.
This commit is contained in:
A. Jiang 2024-11-11 23:04:38 +08:00 committed by GitHub
parent 3af4c2e16e
commit 9f471fd12b
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
4 changed files with 96 additions and 6 deletions
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11
libcxx/include/__iterator/bounded_iter.h
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@ -16,9 +16,13 @@
#include <__config>
#include <__iterator/iterator_traits.h>
#include <__memory/pointer_traits.h>
#include <__type_traits/conjunction.h>
#include <__type_traits/disjunction.h>
#include <__type_traits/enable_if.h>
#include <__type_traits/integral_constant.h>
#include <__type_traits/is_convertible.h>
#include <__type_traits/is_same.h>
#include <__type_traits/make_const_lvalue_ref.h>
#include <__utility/move.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@ -70,7 +74,12 @@ struct __bounded_iter {
_LIBCPP_HIDE_FROM_ABI __bounded_iter(__bounded_iter const&) = default;
_LIBCPP_HIDE_FROM_ABI __bounded_iter(__bounded_iter&&) = default;
template <class _OtherIterator, __enable_if_t< is_convertible<_OtherIterator, _Iterator>::value, int> = 0>
template < class _OtherIterator,
__enable_if_t<
_And< is_convertible<const _OtherIterator&, _Iterator>,
_Or<is_same<reference, __iter_reference<_OtherIterator> >,
is_same<reference, __make_const_lvalue_ref<__iter_reference<_OtherIterator> > > > >::value,
int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __bounded_iter(__bounded_iter<_OtherIterator> const& __other) _NOEXCEPT
: __current_(__other.__current_),
__begin_(__other.__begin_),

13
libcxx/include/__iterator/static_bounded_iter.h
View File

@ -17,9 +17,13 @@
#include <__cstddef/size_t.h>
#include <__iterator/iterator_traits.h>
#include <__memory/pointer_traits.h>
#include <__type_traits/conjunction.h>
#include <__type_traits/disjunction.h>
#include <__type_traits/enable_if.h>
#include <__type_traits/integral_constant.h>
#include <__type_traits/is_convertible.h>
#include <__type_traits/is_same.h>
#include <__type_traits/make_const_lvalue_ref.h>
#include <__utility/move.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@ -93,7 +97,12 @@ struct __static_bounded_iter {
_LIBCPP_HIDE_FROM_ABI __static_bounded_iter(__static_bounded_iter const&) = default;
_LIBCPP_HIDE_FROM_ABI __static_bounded_iter(__static_bounded_iter&&) = default;
template <class _OtherIterator, __enable_if_t<is_convertible<_OtherIterator, _Iterator>::value, int> = 0>
template <class _OtherIterator,
__enable_if_t<
_And< is_convertible<const _OtherIterator&, _Iterator>,
_Or<is_same<reference, __iter_reference<_OtherIterator> >,
is_same<reference, __make_const_lvalue_ref<__iter_reference<_OtherIterator> > > > >::value,
int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
__static_bounded_iter(__static_bounded_iter<_OtherIterator, _Size> const& __other) _NOEXCEPT
: __storage_(__other.__storage_.__current(), __other.__storage_.__begin()) {}
@ -264,7 +273,7 @@ public:
private:
template <class>
friend struct pointer_traits;
template <class, size_t, class>
template <class, size_t>
friend struct __static_bounded_iter;
__static_bounded_iter_storage<_Iterator, _Size> __storage_;

15
libcxx/include/__iterator/wrap_iter.h
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@ -17,9 +17,13 @@
#include <__iterator/iterator_traits.h>
#include <__memory/addressof.h>
#include <__memory/pointer_traits.h>
#include <__type_traits/conjunction.h>
#include <__type_traits/disjunction.h>
#include <__type_traits/enable_if.h>
#include <__type_traits/integral_constant.h>
#include <__type_traits/is_convertible.h>
#include <__type_traits/is_same.h>
#include <__type_traits/make_const_lvalue_ref.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
@ -45,9 +49,14 @@ private:
public:
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter() _NOEXCEPT : __i_() {}
template <class _Up, __enable_if_t<is_convertible<_Up, iterator_type>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter(const __wrap_iter<_Up>& __u) _NOEXCEPT
: __i_(__u.base()) {}
template <
class _OtherIter,
__enable_if_t< _And< is_convertible<const _OtherIter&, _Iter>,
_Or<is_same<reference, __iter_reference<_OtherIter> >,
is_same<reference, __make_const_lvalue_ref<__iter_reference<_OtherIter> > > > >::value,
int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter(const __wrap_iter<_OtherIter>& __u) _NOEXCEPT
: __i_(__u.__i_) {}
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 reference operator*() const _NOEXCEPT { return *__i_; }
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pointer operator->() const _NOEXCEPT {
return std::__to_address(__i_);

63
libcxx/test/libcxx/iterators/contiguous_iterators.conv.compile.pass.cpp Normal file
View File

@ -0,0 +1,63 @@
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// <iterator>
// __bounded_iter<_Iter>
// __static_bounded_iter<_Iter>
// __wrap_iter<_Iter>
// Verify that libc++-wrapped iterators do not permit slicing conversion or construction.
#include <array>
#include <span>
#include <type_traits>
#include <vector>
#include "test_macros.h"
struct Base {};
struct Derived : Base {};
template <class B, class D, bool = std::is_pointer<typename std::array<B, 1>::iterator>::value>
struct test_array_helper : std::true_type {
typedef typename std::array<B, 1>::iterator BaseIter;
typedef typename std::array<D, 1>::iterator DerivedIter;
typedef typename std::array<B, 1>::const_iterator BaseConstIter;
typedef typename std::array<D, 1>::const_iterator DerivedConstIter;
static_assert(!std::is_convertible<DerivedIter, BaseIter>::value, "");
static_assert(!std::is_convertible<DerivedIter, BaseConstIter>::value, "");
static_assert(!std::is_convertible<DerivedConstIter, BaseConstIter>::value, "");
static_assert(!std::is_constructible<BaseIter, DerivedIter>::value, "");
static_assert(!std::is_constructible<BaseConstIter, DerivedIter>::value, "");
static_assert(!std::is_constructible<BaseConstIter, DerivedConstIter>::value, "");
};
template <class B, class D>
struct test_array_helper<B, D, true> : std::true_type {};
static_assert(test_array_helper<Base, Derived>::value, "");
static_assert(!std::is_convertible<std::vector<Derived>::iterator, std::vector<Base>::iterator>::value, "");
static_assert(!std::is_convertible<std::vector<Derived>::iterator, std::vector<Base>::const_iterator>::value, "");
static_assert(!std::is_convertible<std::vector<Derived>::const_iterator, std::vector<Base>::const_iterator>::value, "");
static_assert(!std::is_constructible<std::vector<Base>::iterator, std::vector<Derived>::iterator>::value, "");
static_assert(!std::is_constructible<std::vector<Base>::const_iterator, std::vector<Derived>::iterator>::value, "");
static_assert(!std::is_constructible<std::vector<Base>::const_iterator, std::vector<Derived>::const_iterator>::value,
"");
#if TEST_STD_VER >= 20
static_assert(!std::is_convertible_v<std::span<Derived>::iterator, std::span<Base>::iterator>);
static_assert(!std::is_convertible_v<std::span<Derived>::iterator, std::span<const Base>::iterator>);
static_assert(!std::is_convertible_v<std::span<const Derived>::iterator, std::span<Base>::iterator>);
static_assert(!std::is_constructible_v<std::span<Base>::iterator, std::span<Derived>::iterator>);
static_assert(!std::is_constructible_v<std::span<Base>::iterator, std::span<const Derived>::iterator>);
static_assert(!std::is_constructible_v<std::span<const Base>::iterator, std::span<const Derived>::iterator>);
#endif