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PR libstdc++/87787 avoid undefined null args to memcpy and memmove

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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<char>::widen(const char*, const char*, char*)): Do not
	pass null pointers to memcpy.
	(ctype<char>::narrow(const char*, const char*, char, char*)):
	Likewise.
	(ctype<char>::do_widen(const char*, const char*, char*)):
	Likewise.
	(ctype<char>::do_narrow(const char*, const char*, char, char*)):
	Likewise.

From-SVN: r267651
This commit is contained in:
Jonathan Wakely 2019-01-07 14:58:44 +00:00 • committed by Jonathan Wakely
parent a58fe3c5ca
commit e002afaa8e
3 changed files with 23 additions and 4 deletions
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13
libstdc++-v3/ChangeLog
View file

@ -1,5 +1,18 @@
2019-01-07 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/87787
* include/bits/char_traits.h (char_traits::move): Do not pass null
pointers to memmove.
* include/bits/locale_facets.h
(ctype<char>::widen(const char*, const char*, char*)): Do not
pass null pointers to memcpy.
(ctype<char>::narrow(const char*, const char*, char, char*)):
Likewise.
(ctype<char>::do_widen(const char*, const char*, char*)):
Likewise.
(ctype<char>::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

2
libstdc++-v3/include/bits/char_traits.h
View file

@ -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)));
}

12
libstdc++-v3/include/bits/locale_facets.h
View file

@ -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;
}