* sysdeps/unix/sysv/linux/libc_pthread_init.c: Don't just copy the

	function table, mangle the pointers.
	* sysdeps/pthread/pthread-functions.h: Define PTHFCT_CALL.
	* forward.c: Use PTHFCT_CALL and __libc_pthread_functions_init.
	* sysdeps/pthread/bits/libc-lock.h: When using __libc_pthread_functions
	demangle pointers before use.
	* sysdeps/unix/sysv/linux/s390/jmp-unwind.c: Use PTHFCT_CALL to
	demangle pointer.
	* sysdeps/unix/sysv/linux/jmp-unwind.c: Likewise.
	* sysdeps/pthread/setxid.h: Likewise.

csu/libc-start.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 1998-2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+/* Copyright (C) 1998-2006, 2007 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
@@ -225,7 +225,7 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
     {
       /* Remove the thread-local data.  */
 # ifdef SHARED
-      __libc_pthread_functions.ptr__nptl_deallocate_tsd ();
+      PTHFCT_CALL (ptr__nptl_deallocate_tsd, ());
 # else
       extern void __nptl_deallocate_tsd (void) __attribute ((weak));
       __nptl_deallocate_tsd ();
@@ -235,7 +235,8 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
 	 terminate the entire process.  */
       result = 0;
 # ifdef SHARED
-      unsigned int *const ptr = __libc_pthread_functions.ptr_nthreads;
+      unsigned int *ptr = __libc_pthread_functions.ptr_nthreads;
+      PTR_DEMANGLE (ptr);
 # else
       extern unsigned int __nptl_nthreads __attribute ((weak));
       unsigned int *const ptr = &__nptl_nthreads;

nptl/ChangeLog

@@ -1,3 +1,16 @@
+2007-01-17  Ulrich Drepper  <drepper@redhat.com>
+
+	* sysdeps/unix/sysv/linux/libc_pthread_init.c: Don't just copy the
+	function table, mangle the pointers.
+	* sysdeps/pthread/pthread-functions.h: Define PTHFCT_CALL.
+	* forward.c: Use PTHFCT_CALL and __libc_pthread_functions_init.
+	* sysdeps/pthread/bits/libc-lock.h: When using __libc_pthread_functions
+	demangle pointers before use.
+	* sysdeps/unix/sysv/linux/s390/jmp-unwind.c: Use PTHFCT_CALL to
+	demangle pointer.
+	* sysdeps/unix/sysv/linux/jmp-unwind.c: Likewise.
+	* sysdeps/pthread/setxid.h: Likewise.
+
 2007-01-12  Ulrich Drepper  <drepper@redhat.com>
 
 	* tst-rwlock7.c: Show some more information in case of correct

nptl/forward.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -29,16 +29,17 @@
 
 /* Pointers to the libc functions.  */
 struct pthread_functions __libc_pthread_functions attribute_hidden;
+int __libc_pthread_functions_init attribute_hidden;
 
 
 #define FORWARD2(name, rettype, decl, params, defaction) \
 rettype									      \
 name decl								      \
 {									      \
-  if (__libc_pthread_functions.ptr_##name == NULL)			      \
+  if (!__libc_pthread_functions_init)					      \
     defaction;								      \
 									      \
-  return __libc_pthread_functions.ptr_##name params;			      \
+  return PTHFCT_CALL (ptr_##name, params);				      \
 }
 
 #define FORWARD(name, decl, params, defretval) \

nptl/sysdeps/pthread/bits/libc-lock.h

@@ -1,5 +1,5 @@
 /* libc-internal interface for mutex locks.  NPTL version.
-   Copyright (C) 1996-2001, 2002, 2003, 2005 Free Software Foundation, Inc.
+   Copyright (C) 1996-2003, 2005, 2007 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
@@ -150,13 +150,17 @@ typedef pthread_key_t __libc_key_t;
 
 /* Call thread functions through the function pointer table.  */
 #if defined SHARED && !defined NOT_IN_libc
-# define PTF(NAME) __libc_pthread_functions.ptr_##NAME
+# define PTFAVAIL(NAME) __libc_pthread_functions_init
 # define __libc_ptf_call(FUNC, ARGS, ELSE) \
-  (PTF(FUNC) != NULL ? PTF(FUNC) ARGS : ELSE)
+  (__libc_pthread_functions_init ? PTHFCT_CALL (ptr_##FUNC, ARGS) : ELSE)
+# define __libc_ptf_call_always(FUNC, ARGS) \
+  PTHFCT_CALL (ptr_##FUNC, ARGS)
 #else
-# define PTF(NAME) NAME
+# define PTFAVAIL(NAME) (NAME != NULL)
 # define __libc_ptf_call(FUNC, ARGS, ELSE) \
   __libc_maybe_call (FUNC, ARGS, ELSE)
+# define __libc_ptf_call_always(FUNC, ARGS) \
+  FUNC ARGS
 #endif
 
 
@@ -353,8 +357,9 @@ typedef pthread_key_t __libc_key_t;
 /* Call handler iff the first call.  */
 #define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \
   do {									      \
-    if (PTF(__pthread_once) != NULL)					      \
-      PTF(__pthread_once) (&(ONCE_CONTROL), INIT_FUNCTION);		      \
+    if (PTFAVAIL (__pthread_once))					      \
+      __libc_ptf_call_always (__pthread_once, (&(ONCE_CONTROL),		      \
+					       INIT_FUNCTION));		      \
     else if ((ONCE_CONTROL) == PTHREAD_ONCE_INIT) {			      \
       INIT_FUNCTION ();							      \
       (ONCE_CONTROL) |= 2;						      \
@@ -380,9 +385,10 @@ extern void _pthread_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer
   { struct _pthread_cleanup_buffer _buffer;				      \
     int _avail;								      \
     if (DOIT) {								      \
-      _avail = PTF(_pthread_cleanup_push_defer) != NULL;		      \
+      _avail = PTFAVAIL (_pthread_cleanup_push_defer);			      \
       if (_avail) {							      \
-	PTF(_pthread_cleanup_push_defer) (&_buffer, FCT, ARG);		      \
+	__libc_ptf_call_always (_pthread_cleanup_push_defer, (&_buffer, FCT,  \
+							      ARG));	      \
       } else {								      \
 	_buffer.__routine = (FCT);					      \
 	_buffer.__arg = (ARG);						      \
@@ -394,15 +400,15 @@ extern void _pthread_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer
 /* End critical region with cleanup.  */
 #define __libc_cleanup_region_end(DOIT) \
     if (_avail) {							      \
-      PTF(_pthread_cleanup_pop_restore) (&_buffer, DOIT);		      \
+      __libc_ptf_call_always (_pthread_cleanup_pop_restore, (&_buffer, DOIT));\
     } else if (DOIT)							      \
       _buffer.__routine (_buffer.__arg);				      \
   }
 
 /* Sometimes we have to exit the block in the middle.  */
 #define __libc_cleanup_end(DOIT) \
     if (_avail) {							      \
-      PTF(_pthread_cleanup_pop_restore) (&_buffer, DOIT);		      \
+      __libc_ptf_call_always (_pthread_cleanup_pop_restore, (&_buffer, DOIT));\
     } else if (DOIT)							      \
       _buffer.__routine (_buffer.__arg)
 

nptl/sysdeps/pthread/pthread-functions.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+/* Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
 
@@ -23,6 +23,7 @@
 #include <pthread.h>
 #include <setjmp.h>
 #include <internaltypes.h>
+#include <sysdep.h>
 
 struct xid_command;
 
@@ -100,5 +101,12 @@ struct pthread_functions
 
 /* Variable in libc.so.  */
 extern struct pthread_functions __libc_pthread_functions attribute_hidden;
+extern int __libc_pthread_functions_init attribute_hidden;
+
+#define PTHFCT_CALL(fct, params) \
+  ({ __typeof (__libc_pthread_functions.fct) __p;			      \
+     __p = __libc_pthread_functions.fct;				      \
+     PTR_DEMANGLE (__p);						      \
+     __p params; })
 
 #endif	/* pthread-functions.h */

nptl/sysdeps/pthread/setxid.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2004 Free Software Foundation, Inc.
+/* Copyright (C) 2004, 2007 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
@@ -33,13 +33,12 @@
 # define INLINE_SETXID_SYSCALL(name, nr, args...) \
   ({									\
     int __result;							\
-    if (__builtin_expect (__libc_pthread_functions.ptr__nptl_setxid	\
-			  != NULL, 0))					\
+    if (__builtin_expect (__libc_pthread_functions_init, 0))		\
       {									\
 	struct xid_command __cmd;					\
 	__cmd.syscall_no = __NR_##name;					\
 	__SETXID_##nr (__cmd, args);					\
-	__result = __libc_pthread_functions.ptr__nptl_setxid (&__cmd);	\
+	__result = PTHFCT_CALL (ptr__nptl_setxid, (&__cmd));		\
 	}								\
     else								\
       __result = INLINE_SYSCALL (name, nr, args);			\

nptl/sysdeps/unix/sysv/linux/jmp-unwind.c

@@ -1,5 +1,5 @@
 /* Clean up stack frames unwound by longjmp.  Linux version.
-   Copyright (C) 1995, 1997, 2002, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1995, 1997, 2002, 2003, 2007 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
@@ -29,11 +29,11 @@ void
 _longjmp_unwind (jmp_buf env, int val)
 {
 #ifdef SHARED
-# define fptr __libc_pthread_functions.ptr___pthread_cleanup_upto
+  if (__libc_pthread_functions_init)
+    PTHFCT_CALL (ptr___pthread_cleanup_upto, (env->__jmpbuf,
+					      CURRENT_STACK_FRAME));
 #else
-# define fptr __pthread_cleanup_upto
+  if (__pthread_cleanup_upto != NULL)
+    __pthread_cleanup_upto (env->__jmpbuf, CURRENT_STACK_FRAME);
 #endif
-
-  if (fptr != NULL)
-    fptr (env->__jmpbuf, CURRENT_STACK_FRAME);
 }

nptl/sysdeps/unix/sysv/linux/libc_pthread_init.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2005, 2006 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2005, 2006, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -25,6 +25,7 @@
 #include <string.h>
 #include <pthreadP.h>
 #include <bits/libc-lock.h>
+#include <sysdep.h>
 
 
 #ifdef TLS_MULTIPLE_THREADS_IN_TCB
@@ -46,11 +47,29 @@ __libc_pthread_init (ptr, reclaim, functions)
   __register_atfork (NULL, NULL, reclaim, NULL);
 
 #ifdef SHARED
-  /* We copy the content of the variable pointed to by the FUNCTIONS
-     parameter to one in libc.so since this means access to the array
-     can be done with one memory access instead of two.  */
-  memcpy (&__libc_pthread_functions, functions,
-	  sizeof (__libc_pthread_functions));
+  /* Copy the function pointers into an array in libc.  This enables
+     access with just one memory reference but moreso, it prevents
+     hijacking the function pointers with just one pointer change.  We
+     "encrypt" the function pointers since we cannot write-protect the
+     array easily enough.  */
+  union ptrhack
+  {
+    struct pthread_functions pf;
+    void *parr[1];
+  } const *src;
+  union ptrhack *dest;
+# define NPTRS (sizeof (struct pthread_functions) / sizeof (void *))
+
+  src = (const void *) functions;
+  dest = (void *) &__libc_pthread_functions;
+
+  for (size_t cnt = 0; cnt < NPTRS; ++cnt)
+    {
+      void *p = src->parr[cnt];
+      PTR_MANGLE (p);
+      dest->parr[cnt] = p;
+    }
+  __libc_pthread_functions_init = 1;
 #endif
 
 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
@@ -61,7 +80,7 @@ __libc_pthread_init (ptr, reclaim, functions)
 #ifdef SHARED
 libc_freeres_fn (freeres_libptread)
 {
-  if (__libc_pthread_functions.ptr_freeres != NULL)
-    __libc_pthread_functions.ptr_freeres ();
+  if (__libc_pthread_functions_init)
+    PTHFCT_CALL (ptr_freeres, ());
 }
 #endif

nptl/sysdeps/unix/sysv/linux/s390/jmp-unwind.c

@@ -1,5 +1,5 @@
 /* Clean up stack frames unwound by longjmp.  Linux/s390 version.
-   Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2007 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
@@ -28,14 +28,13 @@ extern void __pthread_cleanup_upto (__jmp_buf env, char *targetframe);
 void
 _longjmp_unwind (jmp_buf env, int val)
 {
+  unsigned char local_var;
+
 #ifdef SHARED
-# define fptr __libc_pthread_functions.ptr___pthread_cleanup_upto
+  if (__libc_pthread_functions_init)
+    PTHFCT_CALL (ptr___pthread_cleanup_upto, (env->__jmpbuf, &local_var));
 #else
-# define fptr __pthread_cleanup_upto
+  if (__pthread_cleanup_upto != NULL)
+    __pthread_cleanup_upto (env->__jmpbuf, &local_var);
 #endif
-
-  unsigned char local_var;
-
-  if (fptr != NULL)
-    fptr (env->__jmpbuf, &local_var);
 }

sysdeps/unix/sysv/linux/fatal-prepare.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2003, 2007 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
@@ -24,10 +24,9 @@
 # include <pthread-functions.h>
 # define FATAL_PREPARE \
   {									      \
-    int (*fp) (int, int *);						      \
-    fp = __libc_pthread_functions.ptr_pthread_setcancelstate;		      \
-    if (fp != NULL)							      \
-      fp (PTHREAD_CANCEL_DISABLE, NULL);				      \
+    if (__libc_pthread_functions_init)					      \
+      PTHFCT_CALL (ptr_pthread_setcancelstate, (PTHREAD_CANCEL_DISABLE,	      \
+						NULL));			      \
   }
 #else
 # pragma weak pthread_setcancelstate