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Re: [PATCH] Don't all __access_noerrno with stack protector from __tunables_init [BZ #21744]


On Thu, Jul 20, 2017 at 1:20 PM, Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
>
> On 20/07/2017 10:04, H.J. Lu wrote:
>> On Thu, Jul 20, 2017 at 5:46 AM, Adhemerval Zanella
>> <adhemerval.zanella@linaro.org> wrote:
>>>
>>> It will fail for architectures that actually define 'err' to something other
>>> than empty 'do { } while (0)' (for instance sparc and tile). Below it is an
>>> updated patch:
>>>
>>> --
>>>
>>>         [BZ #21744]
>>>         * elf/dl-tunables.c: Include not-errno.h header.
>>>         * include/unistd.h (__access_noerrno): Remove definition.
>>>         * sysdeps/unix/sysv/linux/access.c (__access_noerrno): Likewise.
>>>         * sysdeps/generic/not-errno.h: New file.
>>>         * sysdeps/unix/sysv/linux/not-errno.h: Likewise.
>>>
>>> ---
>>>
>>> diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
>>> index 44c160c..231fb8c 100644
>>> --- a/elf/dl-tunables.c
>>> +++ b/elf/dl-tunables.c
>>> @@ -29,6 +29,8 @@
>>>  #define TUNABLES_INTERNAL 1
>>>  #include "dl-tunables.h"
>>>
>>> +#include <not-errno.h>
>>> +
>>>  #if TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring
>>>  # define GLIBC_TUNABLES "GLIBC_TUNABLES"
>>>  #endif
>>> diff --git a/include/unistd.h b/include/unistd.h
>>> index 5b2a414..7f1c2cc 100644
>>> --- a/include/unistd.h
>>> +++ b/include/unistd.h
>>> @@ -182,12 +182,5 @@ extern int __getlogin_r_loginuid (char *name, size_t namesize)
>>>  #   include <dl-unistd.h>
>>>  #  endif
>>>
>>> -#  if IS_IN (rtld) || !defined SHARED
>>> -/* __access variant that does not set errno.  Used in very early initialization
>>> -   code in libc.a and ld.so.  It follows access return semantics (zero for
>>> -   sucess otherwise a value different than 0).  */
>>> -extern __typeof (__access) __access_noerrno attribute_hidden;
>>> -#  endif
>>> -
>>>  # endif
>>>  #endif
>>> diff --git a/sysdeps/generic/not-errno.h b/sysdeps/generic/not-errno.h
>>> new file mode 100644
>>> index 0000000..2aac095
>>> --- /dev/null
>>> +++ b/sysdeps/generic/not-errno.h
>>> @@ -0,0 +1,19 @@
>>> +/* Syscall wrapper that do not set errno.  Generic version.
>>> +   Copyright (C) 2017 Free Software Foundation, Inc.
>>> +   This file is part of the GNU C Library.
>>> +
>>> +   The GNU C Library is free software; you can redistribute it and/or
>>> +   modify it under the terms of the GNU Lesser General Public
>>> +   License as published by the Free Software Foundation; either
>>> +   version 2.1 of the License, or (at your option) any later version.
>>> +
>>> +   The GNU C Library is distributed in the hope that it will be useful,
>>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>>> +   Lesser General Public License for more details.
>>> +
>>> +   You should have received a copy of the GNU Lesser General Public
>>> +   License along with the GNU C Library; if not, see
>>> +   <http://www.gnu.org/licenses/>.  */
>>> +
>>> +extern __typeof (__access) __access_noerrno attribute_hidden;
>>> diff --git a/sysdeps/unix/sysv/linux/access.c b/sysdeps/unix/sysv/linux/access.c
>>> index 67e69bd..366b6b6 100644
>>> --- a/sysdeps/unix/sysv/linux/access.c
>>> +++ b/sysdeps/unix/sysv/linux/access.c
>>> @@ -21,21 +21,6 @@
>>>  #include <sysdep-cancel.h>
>>>
>>>  int
>>> -__access_noerrno (const char *file, int type)
>>> -{
>>> -  int res;
>>> -  INTERNAL_SYSCALL_DECL (err);
>>> -#ifdef __NR_access
>>> -  res = INTERNAL_SYSCALL_CALL (access, err, file, type);
>>> -#else
>>> -  res = INTERNAL_SYSCALL_CALL (faccessat, err, AT_FDCWD, file, type);
>>> -#endif
>>> -  if (INTERNAL_SYSCALL_ERROR_P (res, err))
>>> -    return INTERNAL_SYSCALL_ERRNO (res, err);
>>> -  return 0;
>>> -}
>>> -
>>> -int
>>>  __access (const char *file, int type)
>>>  {
>>>  #ifdef __NR_access
>>> diff --git a/sysdeps/unix/sysv/linux/not-errno.h b/sysdeps/unix/sysv/linux/not-errno.h
>>> new file mode 100644
>>> index 0000000..888bde0
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/not-errno.h
>>> @@ -0,0 +1,31 @@
>>> +/* Syscall wrapper that do not set errno.  Linux version.
>>> +   Copyright (C) 2017 Free Software Foundation, Inc.
>>> +   This file is part of the GNU C Library.
>>> +
>>> +   The GNU C Library is free software; you can redistribute it and/or
>>> +   modify it under the terms of the GNU Lesser General Public
>>> +   License as published by the Free Software Foundation; either
>>> +   version 2.1 of the License, or (at your option) any later version.
>>> +
>>> +   The GNU C Library is distributed in the hope that it will be useful,
>>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>>> +   Lesser General Public License for more details.
>>> +
>>> +   You should have received a copy of the GNU Lesser General Public
>>> +   License along with the GNU C Library; if not, see
>>> +   <http://www.gnu.org/licenses/>.  */
>>> +
>>> +/* This function is used on maybe_enable_malloc_check (elf/dl-tunables.c)
>>> +   and to avoid having to build/use multiple versions if stack protection
>>> +   in enabled it is defined as inline.  */
>>> +static inline int
>>> +__access_noerrno (const char *pathname, int mode)
>>> +{
>>> +  INTERNAL_SYSCALL_DECL (err);
>>> +#ifdef __NR_access
>>> +  return INTERNAL_SYSCALL_CALL (access, err, pathname, mode);
>>> +#else
>>> +  return INTERNAL_SYSCALL_CALL (faccessat, err, AT_FDCWD, file, type);
>>> +#endif
>>> +}
>>> --
>>> 2.7.4
>>
>> LGTM.
>>
>> Thanks.
>>
>
> Right, I will commit this shortly if no one opposes it.

Have you checked it in?

Thanks.

-- 
H.J.


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