[libcxx-commits] [libcxx] 9f471fd - [libc++][hardening] Constrain construction for `__{(static_)bounded, wrap}_iter` (#115271)
via libcxx-commits
libcxx-commits at lists.llvm.org
Mon Nov 11 07:04:42 PST 2024
Author: A. Jiang
Date: 2024-11-11T23:04:38+08:00
New Revision: 9f471fd12b9e2d6264f27974feaf893445e92393
URL: https://github.com/llvm/llvm-project/commit/9f471fd12b9e2d6264f27974feaf893445e92393
DIFF: https://github.com/llvm/llvm-project/commit/9f471fd12b9e2d6264f27974feaf893445e92393.diff
LOG: [libc++][hardening] Constrain construction for `__{(static_)bounded,wrap}_iter` (#115271)
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.
Added:
libcxx/test/libcxx/iterators/contiguous_iterators.conv.compile.pass.cpp
Modified:
libcxx/include/__iterator/bounded_iter.h
libcxx/include/__iterator/static_bounded_iter.h
libcxx/include/__iterator/wrap_iter.h
Removed:
################################################################################
diff --git a/libcxx/include/__iterator/bounded_iter.h b/libcxx/include/__iterator/bounded_iter.h
index ae6fbb6b59bcff..d12750d1f81ac7 100644
--- a/libcxx/include/__iterator/bounded_iter.h
+++ b/libcxx/include/__iterator/bounded_iter.h
@@ -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_),
diff --git a/libcxx/include/__iterator/static_bounded_iter.h b/libcxx/include/__iterator/static_bounded_iter.h
index 9794c220384f55..8f4fbdf6dff961 100644
--- a/libcxx/include/__iterator/static_bounded_iter.h
+++ b/libcxx/include/__iterator/static_bounded_iter.h
@@ -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 @@ struct __static_bounded_iter {
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_;
diff --git a/libcxx/include/__iterator/wrap_iter.h b/libcxx/include/__iterator/wrap_iter.h
index 2856833e600798..966c4675b7049a 100644
--- a/libcxx/include/__iterator/wrap_iter.h
+++ b/libcxx/include/__iterator/wrap_iter.h
@@ -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 @@ class __wrap_iter {
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_);
diff --git a/libcxx/test/libcxx/iterators/contiguous_iterators.conv.compile.pass.cpp b/libcxx/test/libcxx/iterators/contiguous_iterators.conv.compile.pass.cpp
new file mode 100644
index 00000000000000..372559594143ef
--- /dev/null
+++ b/libcxx/test/libcxx/iterators/contiguous_iterators.conv.compile.pass.cpp
@@ -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
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