svn commit: r276681 - in head/lib: libc/include libc/sys libthr/thread

[Konstantin Belousov]

Author: kib
Date: Mon Jan  5 01:06:54 2015
New Revision: 276681
URL: https://svnweb.freebsd.org/changeset/base/276681

Log:
  Avoid calling internal libc function through PLT or accessing data
  though GOT, by staticizing and hiding.  Add setter for
  __error_selector to hide it as well.
  
  Suggested and reviewed by:	jilles
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/lib/libc/include/libc_private.h
  head/lib/libc/sys/Symbol.map
  head/lib/libc/sys/__error.c
  head/lib/libthr/thread/thr_private.h
  head/lib/libthr/thread/thr_syscalls.c

Modified: head/lib/libc/include/libc_private.h
==============================================================================
--- head/lib/libc/include/libc_private.h	Mon Jan  5 01:05:35 2015	(r276680)
+++ head/lib/libc/include/libc_private.h	Mon Jan  5 01:06:54 2015	(r276681)
@@ -173,13 +173,13 @@ typedef pthread_func_t pthread_func_entr
 
 extern pthread_func_entry_t __thr_jtable[];
 
-extern int *(*__error_selector)(void);
+void	__set_error_selector(int *(*arg)(void));
 int	_pthread_mutex_init_calloc_cb_stub(pthread_mutex_t *mutex,
 	    void *(calloc_cb)(__size_t, __size_t));
 
 typedef int (*interpos_func_t)(void);
 interpos_func_t *__libc_interposing_slot(int interposno);
-extern interpos_func_t __libc_interposing[];
+extern interpos_func_t __libc_interposing[] __hidden;
 
 enum {
 	INTERPOS_accept,

Modified: head/lib/libc/sys/Symbol.map
==============================================================================
--- head/lib/libc/sys/Symbol.map	Mon Jan  5 01:05:35 2015	(r276680)
+++ head/lib/libc/sys/Symbol.map	Mon Jan  5 01:06:54 2015	(r276681)
@@ -1045,8 +1045,7 @@ FBSDprivate_1.0 {
 	__sys_write;
 	_writev;
 	__sys_writev;
-	__error_unthreaded;
-	__error_selector;
+	__set_error_selector;
 	nlm_syscall;
 	gssd_syscall;
 	__libc_interposing_slot;

Modified: head/lib/libc/sys/__error.c
==============================================================================
--- head/lib/libc/sys/__error.c	Mon Jan  5 01:05:35 2015	(r276680)
+++ head/lib/libc/sys/__error.c	Mon Jan  5 01:06:54 2015	(r276681)
@@ -32,13 +32,21 @@ __FBSDID("$FreeBSD$");
 
 extern int errno;
 
-int *
+static int *
 __error_unthreaded(void)
 {
-	return(&errno);
+
+	return (&errno);
 }
 
-int *(*__error_selector)(void) = __error_unthreaded;
+static int *(*__error_selector)(void) = __error_unthreaded;
+
+void
+__set_error_selector(int *(*arg)(void))
+{
+
+	__error_selector = arg;
+}
 
 int *
 __error(void)

Modified: head/lib/libthr/thread/thr_private.h
==============================================================================
--- head/lib/libthr/thread/thr_private.h	Mon Jan  5 01:05:35 2015	(r276680)
+++ head/lib/libthr/thread/thr_private.h	Mon Jan  5 01:06:54 2015	(r276681)
@@ -914,7 +914,7 @@ void _thr_tsd_unload(struct dl_phdr_info
 void _thr_sigact_unload(struct dl_phdr_info *phdr_info) __hidden;
 void _thr_stack_fix_protection(struct pthread *thrd);
 
-int *__error_threaded(void);
+int *__error_threaded(void) __hidden;
 void __thr_interpose_libc(void) __hidden;
 pid_t __thr_fork(void);
 int __thr_pause(void) __hidden;

Modified: head/lib/libthr/thread/thr_syscalls.c
==============================================================================
--- head/lib/libthr/thread/thr_syscalls.c	Mon Jan  5 01:05:35 2015	(r276680)
+++ head/lib/libthr/thread/thr_syscalls.c	Mon Jan  5 01:06:54 2015	(r276681)
@@ -692,7 +692,7 @@ void
 __thr_interpose_libc(void)
 {
 
-	__error_selector = __error_threaded;
+	__set_error_selector(__error_threaded);
 #define	SLOT(name)					\
 	*(__libc_interposing_slot(INTERPOS_##name)) =	\
 	    (interpos_func_t)__thr_##name;