diff mbox

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

Message ID 20170716191924.GA7226@gmail.com
State New, archived
Headers show

Commit Message

H.J. Lu July 16, 2017, 7:19 p.m. UTC
maybe_enable_malloc_check, which is called by __tunables_init, call
__access_noerrno.  It isn't problem when maybe_enable_malloc_check 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 maybe_enable_malloc_check to call _dl_access_noerrno
instead.  For ld.so or glibc built without stack protector, it is defined
to __access_noerrno.  Otherwise a special version of __access_noerrno
without stack protector is used by maybe_enable_malloc_check in libc.a.

Tested on x86-64 with and without --enable-stack-protector=all.

OK for master?

H.J.
---
	[BZ #21744]
	* config.h.in (HAVE_STACK_PROTECTOR): New.
	* configure.ac (HAVE_STACK_PROTECTOR): AC_DEFINE if configured
	with stack protector.
	* configure: Regenerated.
	* elf/dl-support.c [HAVE_TUNABLES != 0]: Include <access.c> if
	__access_noerrno is defined.
	* elf/dl-tunables.c (maybe_enable_malloc_check): Replace
	__access_noerrno with _dl_access_noerrno.
	* elf/dl-tunables.h [SHARED != 0 || HAVE_STACK_PROTECTOR == 0]
	(_dl_access_noerrno): New macro.
	[SHARED == 0 && HAVE_STACK_PROTECTOR != 0] (__access_noerrno):
	New macro.
	[SHARED == 0 && HAVE_STACK_PROTECTOR != 0] (_dl_access_noerrno):
	New prototype.
	* io/access.c (__access): Don't define if __access_noerrno is
	defined.
	* sysdeps/mach/hurd/access.c (__access): Likewise.
	* sysdeps/unix/sysv/linux/access.c (__access): Likewise.
---
 config.h.in                      |  4 ++++
 configure                        |  6 ++++++
 configure.ac                     |  3 +++
 elf/dl-support.c                 |  8 +++++++-
 elf/dl-tunables.c                |  3 ++-
 elf/dl-tunables.h                | 14 ++++++++++++++
 io/access.c                      |  2 ++
 sysdeps/mach/hurd/access.c       |  2 ++
 sysdeps/unix/sysv/linux/access.c |  2 ++
 9 files changed, 42 insertions(+), 2 deletions(-)

Comments

Tulio Magno Quites Machado Filho July 17, 2017, 8:04 p.m. UTC | #1
"H.J. Lu" <hjl.tools@gmail.com> writes:

> maybe_enable_malloc_check, which is called by __tunables_init, call
> __access_noerrno.  It isn't problem when maybe_enable_malloc_check 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 maybe_enable_malloc_check to call _dl_access_noerrno
> instead.  For ld.so or glibc built without stack protector, it is defined
> to __access_noerrno.  Otherwise a special version of __access_noerrno
> without stack protector is used by maybe_enable_malloc_check in libc.a.
>
> Tested on x86-64 with and without --enable-stack-protector=all.


> diff --git a/elf/dl-support.c b/elf/dl-support.c
> index c22be854f4..3228cf4020 100644
> --- a/elf/dl-support.c
> +++ b/elf/dl-support.c
> @@ -164,7 +164,13 @@ uint64_t _dl_hwcap2 __attribute__ ((nocommon));
>  /* The value of the FPU control word the kernel will preset in hardware.  */
>  fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
>
> -#if !HAVE_TUNABLES
> +#if HAVE_TUNABLES
> +# ifdef __access_noerrno

It's necessary to include dl-tunables.h before testing for __access_noerrno.

Tested on ppc64le with that modification.
diff mbox

Patch

diff --git a/config.h.in b/config.h.in
index 22418576a0..01b1a5374b 100644
--- a/config.h.in
+++ b/config.h.in
@@ -250,4 +250,8 @@ 
    in i386 6 argument syscall issue).  */
 #define CAN_USE_REGISTER_ASM_EBP 0
 
+/* Build glibc with -fstack-protector, -fstack-protector-all, or
+   -fstack-protector-strong.  */
+#define HAVE_STACK_PROTECTOR 0
+
 #endif
diff --git a/configure b/configure
index d8e1c50e11..5cc8b2f979 100755
--- a/configure
+++ b/configure
@@ -4051,14 +4051,20 @@  if test "$enable_stack_protector" = yes && test "$libc_cv_ssp" = yes; then
   stack_protector="-fstack-protector"
   $as_echo "#define STACK_PROTECTOR_LEVEL 1" >>confdefs.h
 
+  $as_echo "#define HAVE_STACK_PROTECTOR 1" >>confdefs.h
+
 elif test "$enable_stack_protector" = all && test "$libc_cv_ssp_all" = yes; then
   stack_protector="-fstack-protector-all"
   $as_echo "#define STACK_PROTECTOR_LEVEL 2" >>confdefs.h
 
+  $as_echo "#define HAVE_STACK_PROTECTOR 1" >>confdefs.h
+
 elif test "$enable_stack_protector" = strong && test "$libc_cv_ssp_strong" = yes; then
   stack_protector="-fstack-protector-strong"
   $as_echo "#define STACK_PROTECTOR_LEVEL 3" >>confdefs.h
 
+  $as_echo "#define HAVE_STACK_PROTECTOR 1" >>confdefs.h
+
 else
   stack_protector="-fno-stack-protector"
   $as_echo "#define STACK_PROTECTOR_LEVEL 0" >>confdefs.h
diff --git a/configure.ac b/configure.ac
index 77456aa8d9..05a0182792 100644
--- a/configure.ac
+++ b/configure.ac
@@ -687,12 +687,15 @@  fi
 if test "$enable_stack_protector" = yes && test "$libc_cv_ssp" = yes; then
   stack_protector="-fstack-protector"
   AC_DEFINE(STACK_PROTECTOR_LEVEL, 1)
+  AC_DEFINE(HAVE_STACK_PROTECTOR)
 elif test "$enable_stack_protector" = all && test "$libc_cv_ssp_all" = yes; then
   stack_protector="-fstack-protector-all"
   AC_DEFINE(STACK_PROTECTOR_LEVEL, 2)
+  AC_DEFINE(HAVE_STACK_PROTECTOR)
 elif test "$enable_stack_protector" = strong && test "$libc_cv_ssp_strong" = yes; then
   stack_protector="-fstack-protector-strong"
   AC_DEFINE(STACK_PROTECTOR_LEVEL, 3)
+  AC_DEFINE(HAVE_STACK_PROTECTOR)
 else
   stack_protector="-fno-stack-protector"
   AC_DEFINE(STACK_PROTECTOR_LEVEL, 0)
diff --git a/elf/dl-support.c b/elf/dl-support.c
index c22be854f4..3228cf4020 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -164,7 +164,13 @@  uint64_t _dl_hwcap2 __attribute__ ((nocommon));
 /* The value of the FPU control word the kernel will preset in hardware.  */
 fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
 
-#if !HAVE_TUNABLES
+#if HAVE_TUNABLES
+# ifdef __access_noerrno
+/* If __access_noerrno is defined, include <access.c> to define the
+   special version of __access_noerrno without stack protector.  */
+#  include <access.c>
+# endif
+#else
 /* This is not initialized to HWCAP_IMPORTANT, matching the definition
    of _dl_important_hwcaps, below, where no hwcap strings are ever
    used.  This mask is still used to mediate the lookups in the cache
diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
index 44c160cac5..3fef367d72 100644
--- a/elf/dl-tunables.c
+++ b/elf/dl-tunables.c
@@ -281,7 +281,8 @@  __always_inline
 maybe_enable_malloc_check (void)
 {
   tunable_id_t id = TUNABLE_ENUM_NAME (glibc, malloc, check);
-  if (__libc_enable_secure && __access_noerrno ("/etc/suid-debug", F_OK) == 0)
+  if (__libc_enable_secure
+      && _dl_access_noerrno ("/etc/suid-debug", F_OK) == 0)
     tunable_list[id].security_level = TUNABLE_SECLEVEL_NONE;
 }
 
diff --git a/elf/dl-tunables.h b/elf/dl-tunables.h
index c92882acba..62d5ef841f 100644
--- a/elf/dl-tunables.h
+++ b/elf/dl-tunables.h
@@ -30,6 +30,20 @@  __tunables_init (char **unused __attribute__ ((unused)))
 }
 #else
 
+# if defined SHARED || !HAVE_STACK_PROTECTOR
+/* maybe_enable_malloc_check in ld.so uses the special version of
+   __access_noerrno without stack protector.  When glibc is built
+   without stack protector, maybe_enable_malloc_check in libc.a uses
+   the regular version of __access_noerrno, which is compiled without
+   stack protector.  */
+#  define _dl_access_noerrno __access_noerrno
+# else
+/* When glibc is built with stack protector, maybe_enable_malloc_check
+   in libc.a must use the special version of __access_noerrno without
+   stack protector.  */
+#  define __access_noerrno _dl_access_noerrno
+extern int _dl_access_noerrno (const char *, int);
+# endif
 # include <stddef.h>
 # include "dl-tunable-types.h"
 
diff --git a/io/access.c b/io/access.c
index 72eba36e3f..d27e789923 100644
--- a/io/access.c
+++ b/io/access.c
@@ -26,6 +26,7 @@  __access_noerrno (const char *file, int type)
   return -1;
 }
 
+#ifndef __access_noerrno
 /* Test for access to FILE.  */
 int
 __access (const char *file, int type)
@@ -42,3 +43,4 @@  __access (const char *file, int type)
 stub_warning (access)
 
 weak_alias (__access, access)
+#endif
diff --git a/sysdeps/mach/hurd/access.c b/sysdeps/mach/hurd/access.c
index 185e000c9d..329a9fc70a 100644
--- a/sysdeps/mach/hurd/access.c
+++ b/sysdeps/mach/hurd/access.c
@@ -164,6 +164,7 @@  __access_noerrno (const char *file, int type)
   return access_common (file, type, hurd_fail_noerrno);
 }
 
+#ifndef __access_noerrno
 /* Test for access to FILE by our real user and group IDs.  */
 int
 __access (const char *file, int type)
@@ -171,3 +172,4 @@  __access (const char *file, int type)
   return access_common (file, type, hurd_fail_seterrno);
 }
 weak_alias (__access, access)
+#endif
diff --git a/sysdeps/unix/sysv/linux/access.c b/sysdeps/unix/sysv/linux/access.c
index 67e69bd163..f0e7dd2e83 100644
--- a/sysdeps/unix/sysv/linux/access.c
+++ b/sysdeps/unix/sysv/linux/access.c
@@ -35,6 +35,7 @@  __access_noerrno (const char *file, int type)
   return 0;
 }
 
+#ifndef __access_noerrno
 int
 __access (const char *file, int type)
 {
@@ -45,3 +46,4 @@  __access (const char *file, int type)
 #endif
 }
 weak_alias (__access, access)
+#endif