diff mbox

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

Message ID 80b843b8-6e3c-ccbe-5a6f-b37e18dbdbae@linaro.org
State Dropped
Headers

Commit Message

Adhemerval Zanella Netto July 18, 2017, 1:52 p.m. UTC 
  On 18/07/2017 10:44, H.J. Lu wrote:
> This should work for Linux.
> 
> Thanks.
> 

Now with a proper patch:

[PATCH] tunables: Use direct syscall for access (BZ#21744)

The function maybe_enable_malloc_check, which is called by
__tunables_init, calls __access_noerrno.  It isn't problem when
symbol is is in ld.so, which has a special version of __access_noerrno
without stack protector.  But when glibc is built with stack protector,
maybe_enable_malloc_check in libc.a can't call the regular version of
__access_noerrno with stack protector.

This patch changes how Linux defines the __access_noerrno to be an
inline call instead and thus preventing defining different build
rules for ld/static and shared.

	H.J. Lu  <hongjiu.lu@intel.com>
	Adhemerval Zanella  <adhemerval.zanella@linaro.org>

	* 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.
---
 ChangeLog                           |  9 +++++++++
 elf/dl-tunables.c                   |  2 ++
 include/unistd.h                    |  7 -------
 sysdeps/generic/not-errno.h         | 19 +++++++++++++++++++
 sysdeps/unix/sysv/linux/access.c    | 15 ---------------
 sysdeps/unix/sysv/linux/not-errno.h | 30 ++++++++++++++++++++++++++++++
 6 files changed, 60 insertions(+), 22 deletions(-)
 create mode 100644 sysdeps/generic/not-errno.h
 create mode 100644 sysdeps/unix/sysv/linux/not-errno.h
diff mbox

Patch

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..4957038
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/not-errno.h
@@ -0,0 +1,30 @@ 
+/* 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)
+{
+#ifdef __NR_access
+  return INTERNAL_SYSCALL_CALL (access, pathname, mode);
+#else
+  return INTERNAL_SYSCALL_CALL (faccessat, AT_FDCWD, file, type);
+#endif
+}