From e002afaa8e01395110c77de18bb7e0fa030ba019 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Mon, 7 Jan 2019 14:58:44 +0000 Subject: [PATCH] PR libstdc++/87787 avoid undefined null args to memcpy and memmove The C++ char_traits and ctype APIs do not disallow null pointer arguments, so we need explicit checks to ensure we don't forward null pointers to memcpy or memmove. PR libstdc++/87787 * include/bits/char_traits.h (char_traits::move): Do not pass null pointers to memmove. * include/bits/locale_facets.h (ctype::widen(const char*, const char*, char*)): Do not pass null pointers to memcpy. (ctype::narrow(const char*, const char*, char, char*)): Likewise. (ctype::do_widen(const char*, const char*, char*)): Likewise. (ctype::do_narrow(const char*, const char*, char, char*)): Likewise. From-SVN: r267651 --- libstdc++-v3/ChangeLog | 13 +++++++++++++ libstdc++-v3/include/bits/char_traits.h | 2 ++ libstdc++-v3/include/bits/locale_facets.h | 12 ++++++++---- 3 files changed, 23 insertions(+), 4 deletions(-) diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index a2c01ad..0babce9 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,5 +1,18 @@ 2019-01-07 Jonathan Wakely + PR libstdc++/87787 + * include/bits/char_traits.h (char_traits::move): Do not pass null + pointers to memmove. + * include/bits/locale_facets.h + (ctype::widen(const char*, const char*, char*)): Do not + pass null pointers to memcpy. + (ctype::narrow(const char*, const char*, char, char*)): + Likewise. + (ctype::do_widen(const char*, const char*, char*)): + Likewise. + (ctype::do_narrow(const char*, const char*, char, char*)): + Likewise. + * doc/xml/manual/spine.xml: Update copyright years. * doc/xml/manual/status_cxx2017.xml: Adjust note about -lstdc++fs. * doc/xml/manual/using.xml: Remove requirement to link with -lstdc++fs diff --git a/libstdc++-v3/include/bits/char_traits.h b/libstdc++-v3/include/bits/char_traits.h index a2ba5da..06e04ce 100644 --- a/libstdc++-v3/include/bits/char_traits.h +++ b/libstdc++-v3/include/bits/char_traits.h @@ -183,6 +183,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION char_traits<_CharT>:: move(char_type* __s1, const char_type* __s2, std::size_t __n) { + if (__n == 0) + return __s1; return static_cast<_CharT*>(__builtin_memmove(__s1, __s2, __n * sizeof(char_type))); } diff --git a/libstdc++-v3/include/bits/locale_facets.h b/libstdc++-v3/include/bits/locale_facets.h index 33cff65..66ac9c0 100644 --- a/libstdc++-v3/include/bits/locale_facets.h +++ b/libstdc++-v3/include/bits/locale_facets.h @@ -896,7 +896,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { if (_M_widen_ok == 1) { - __builtin_memcpy(__to, __lo, __hi - __lo); + if (__builtin_expect(__hi != __lo, true)) + __builtin_memcpy(__to, __lo, __hi - __lo); return __hi; } if (!_M_widen_ok) @@ -961,7 +962,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { if (__builtin_expect(_M_narrow_ok == 1, true)) { - __builtin_memcpy(__to, __lo, __hi - __lo); + if (__builtin_expect(__hi != __lo, true)) + __builtin_memcpy(__to, __lo, __hi - __lo); return __hi; } if (!_M_narrow_ok) @@ -1100,7 +1102,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION virtual const char* do_widen(const char* __lo, const char* __hi, char_type* __to) const { - __builtin_memcpy(__to, __lo, __hi - __lo); + if (__builtin_expect(__hi != __lo, true)) + __builtin_memcpy(__to, __lo, __hi - __lo); return __hi; } @@ -1153,7 +1156,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION do_narrow(const char_type* __lo, const char_type* __hi, char __dfault __attribute__((__unused__)), char* __to) const { - __builtin_memcpy(__to, __lo, __hi - __lo); + if (__builtin_expect(__hi != __lo, true)) + __builtin_memcpy(__to, __lo, __hi - __lo); return __hi; } -- 2.7.4