* sysdeps/generic/dl-osinfo.h (_dl_setup_stack_chk_guard): Take

	one parameter.  If non-NULL use it to initialize return value.
	(_dl_setup_pointer_guard): New function.
	* sysdeps/unix/sysv/linux/dl-osinfo.h: Likewise.
	* sysdeps/generic/ldsodefs.h: Declare _dl_random.
	* elf/rtld.c (security_init): Pass _dl_random to
	_dl_setup_stack_chk_guard.  Call _dl_setup_pointer_guard to initialize
	pointer_chk_guard.
	* elf/dl-sysdep.c (_dl_random): New variable.
	(_dl_sysdep_start): Handle AT_RANDOM.
	(_dl_show_auxv): Likewise.
	* elf/dl-support.c (_dl_random): New variable.
	(_dl_aux_init): Handle AT_RANDOM.
	* csu/libc-start.c [!SHARED] (libc_start_main): Pass _dl_random
	to _dl_setup_stack_chk_guard.

	* elf/elf.h (AT_RANDOM): Define AT_BASE_PLATFORM and AT_RANDOM.

3 files changed, 22 insertions, 11 deletions

diff --git a/elf/dl-support.c b/elf/dl-support.c
index 6bd573e..59a8dd9 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -1,5 +1,5 @@
 /* Support for dynamic linking code in static libc.
-   Copyright (C) 1996-2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+   Copyright (C) 1996-2008, 2009 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
@@ -84,6 +84,9 @@ struct r_scope_elem _dl_initial_searchlist;
 int _dl_starting_up = 1;
 #endif
 
+/* Random data provided by the kernel.  */
+void *_dl_random;
+
 /* Get architecture specific initializer.  */
 #include <dl-procinfo.c>
 
@@ -216,6 +219,9 @@ _dl_aux_init (ElfW(auxv_t) *av)
 	__libc_enable_secure = av->a_un.a_val;
 	__libc_enable_secure_decided = 1;
 	break;
+      case AT_RANDOM:
+	_dl_random = (void *) av->a_un.a_val;
+	break;
 # ifdef DL_PLATFORM_AUXV
       DL_PLATFORM_AUXV
 # endif
diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c
index e6f4272..a44bee7 100644
--- a/elf/dl-sysdep.c
+++ b/elf/dl-sysdep.c
@@ -1,5 +1,5 @@
 /* Operating system support for run-time dynamic linker.  Generic Unix version.
-   Copyright (C) 1995-1998, 2000-2007, 2008 Free Software Foundation, Inc.
+   Copyright (C) 1995-1998, 2000-2008, 2009 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
@@ -62,6 +62,7 @@ int __libc_multiple_libcs = 0;	/* Defining this here avoids the inclusion
 void *__libc_stack_end attribute_relro = NULL;
 rtld_hidden_data_def(__libc_stack_end)
 static ElfW(auxv_t) *_dl_auxv attribute_relro;
+void *_dl_random attribute_relro = NULL;
 
 #ifndef DL_FIND_ARG_COMPONENTS
 # define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp)	\
@@ -173,6 +174,9 @@ _dl_sysdep_start (void **start_argptr,
 	GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
 	break;
 #endif
+      case AT_RANDOM:
+	_dl_random = (void *) av->a_un.a_val;
+	break;
 #ifdef DL_PLATFORM_AUXV
       DL_PLATFORM_AUXV
 #endif
@@ -294,6 +298,7 @@ _dl_show_auxv (void)
 	  [AT_SECURE - 2] =		{ "AT_SECURE:       ", dec },
 	  [AT_SYSINFO - 2] =		{ "AT_SYSINFO:      0x", hex },
 	  [AT_SYSINFO_EHDR - 2] =	{ "AT_SYSINFO_EHDR: 0x", hex },
+	  [AT_RANDOM - 2] =		{ "AT_RANDOM:       0x", hex },
 	};
       unsigned int idx = (unsigned int) (av->a_type - 2);
 
diff --git a/elf/rtld.c b/elf/rtld.c
index 46bece7..aa4c030 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -1,5 +1,5 @@
 /* Run time dynamic linker.
-   Copyright (C) 1995-2006, 2007, 2008 Free Software Foundation, Inc.
+   Copyright (C) 1995-2006, 2007, 2008, 2009 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
@@ -841,7 +841,7 @@ static void
 security_init (void)
 {
   /* Set up the stack checker's canary.  */
-  uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard ();
+  uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
 #ifdef THREAD_SET_STACK_GUARD
   THREAD_SET_STACK_GUARD (stack_chk_guard);
 #else
@@ -851,18 +851,18 @@ security_init (void)
   /* Set up the pointer guard as well, if necessary.  */
   if (GLRO(dl_pointer_guard))
     {
-      // XXX If it is cheap, we should use a separate value.
-      uintptr_t pointer_chk_guard = stack_chk_guard;
-#ifndef HP_TIMING_NONAVAIL
-      hp_timing_t now;
-      HP_TIMING_NOW (now);
-      pointer_chk_guard ^= now;
-#endif
+      uintptr_t pointer_chk_guard = _dl_setup_pointer_guard (_dl_random,
+							     stack_chk_guard);
 #ifdef THREAD_SET_POINTER_GUARD
       THREAD_SET_POINTER_GUARD (pointer_chk_guard);
 #endif
       __pointer_chk_guard_local = pointer_chk_guard;
     }
+
+  /* We do not need the _dl_random value anymore.  The less
+     information we leave behind, the better, so clear the
+     variable.  */
+  _dl_random = NULL;
 }