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>

	[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.

(cherry picked from commit 95a73392580761abc62fc9b1386d232cd55878e9)

diff --git a/ChangeLog b/ChangeLog
index f08f7f512d9e55d242f29466461f6dc04141bbfb..48249e38c6490603d33ad35e5efd27544d6033c9 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2017-07-24  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
+           H.J. Lu  <hongjiu.lu@intel.com>
+
+       [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.
+
 2018-01-18  Arjun Shankar  <arjun@redhat.com>
 
        [BZ #22343]

diff --git a/NEWS b/NEWS
index f1aa7aa9f745af10912ea18298c5545009587d9b..f4335dd6a4b3ec4d2d2712b6b35167729f227e48 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -68,6 +68,7 @@ The following bugs are resolved with this release:
   [21386] Assertion in fork for distinct parent PID is incorrect
   [21624] Unsafe alloca allows local attackers to alias stack and heap (CVE-2017-1000366)
   [21654] nss: Fix invalid cast in group merging
+  [21744] tunables: Use direct syscall for access
   [21778] Robust mutex may deadlock
   [21915] getaddrinfo: incorrect result handling for NSS service modules
   [21922] getaddrinfo with AF_INET(6) returns EAI_NONAME, not EAI_NODATA

diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
index e42aa670033131f75a682aedf492c017f2bcb673..7ee3f98c8d8c3bf9c97885b4830ff50cff6d445e 100644 (file)
--- a/elf/dl-tunables.c
+++ b/elf/dl-tunables.c
@@ -30,6 +30,8 @@
 #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 16d68a15056f7d7cb37ab8a3777bc76cb10f5ac7..d2802b2b3e84f519248cf613109048036f9fed69 100644 (file)
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -181,13 +181,6 @@ 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
-
 __END_DECLS
 # endif
 

diff --git a/sysdeps/generic/not-errno.h b/sysdeps/generic/not-errno.h
new file mode 100644 (file)
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 67e69bd16363bbc91f0ab3d65378855444d0b261..366b6b646173cb04fac622acc8c8ec4bde005a2b 100644 (file)
--- a/sysdeps/unix/sysv/linux/access.c
+++ b/sysdeps/unix/sysv/linux/access.c
@@ -20,21 +20,6 @@
 #include <unistd.h>
 #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)
 {

diff --git a/sysdeps/unix/sysv/linux/not-errno.h b/sysdeps/unix/sysv/linux/not-errno.h
new file mode 100644 (file)
index 0000000..65f93f3
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/not-errno.h
@@ -0,0 +1,35 @@
+/* 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)
+{
+  int res;
+  INTERNAL_SYSCALL_DECL (err);
+#ifdef __NR_access
+  res = INTERNAL_SYSCALL_CALL (access, err, pathname, mode);
+#else
+  res = INTERNAL_SYSCALL_CALL (faccessat, err, AT_FDCWD, pathname, mode);
+#endif
+  if (INTERNAL_SYSCALL_ERROR_P (res, err))
+    return INTERNAL_SYSCALL_ERRNO (res, err);
+  return 0;
+}