Skip to content

Commit

Permalink
* sysdeps/generic/dl-osinfo.h (_dl_setup_stack_chk_guard): Take
Browse files Browse the repository at this point in the history
	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.
  • Loading branch information
Ulrich Drepper committed Jan 11, 2009
1 parent 5b656a0 commit 965cb60
Show file tree
Hide file tree
Showing 7 changed files with 112 additions and 31 deletions.
20 changes: 20 additions & 0 deletions ChangeLog
Original file line number Diff line number Diff line change
@@ -1,3 +1,23 @@
2009-01-10 Ulrich Drepper <drepper@redhat.com>

* 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.

2009-01-10 Roland McGrath <roland@redhat.com>

* nscd/nscd.c (parse_opt): Use argp_error for bad -i argument.
Expand Down
8 changes: 7 additions & 1 deletion elf/dl-support.c
Original file line number Diff line number Diff line change
@@ -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
Expand Down Expand Up @@ -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>

Expand Down Expand Up @@ -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
Expand Down
7 changes: 6 additions & 1 deletion elf/dl-sysdep.c
Original file line number Diff line number Diff line change
@@ -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
Expand Down Expand Up @@ -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) \
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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);

Expand Down
18 changes: 9 additions & 9 deletions elf/rtld.c
Original file line number Diff line number Diff line change
@@ -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
Expand Down Expand Up @@ -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
Expand All @@ -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;
}


Expand Down
29 changes: 23 additions & 6 deletions sysdeps/generic/dl-osinfo.h
Original file line number Diff line number Diff line change
@@ -1,12 +1,29 @@
#include <stdint.h>

static inline uintptr_t __attribute__ ((always_inline))
_dl_setup_stack_chk_guard (void)
_dl_setup_stack_chk_guard (void *dl_random)
{
uintptr_t ret = 0;
unsigned char *p = (unsigned char *) &ret;
p[sizeof (ret) - 1] = 255;
p[sizeof (ret) - 2] = '\n';
p[0] = 0;
uintptr_t ret;
if (dl_random == NULL)
{
ret = 0;
unsigned char *p = (unsigned char *) &ret;
p[sizeof (ret) - 1] = 255;
p[sizeof (ret) - 2] = '\n';
p[0] = 0;
}
else
memcmp (&ret, dl_random, sizeof (ret));
return ret;
}

static inline uintptr_t __attribute__ ((always_inline))
_dl_setup_pointer_guard (void *dl_random, uintptr_t stack_chk_guard)
{
uintptr_t ret;
if (dl_random == NULL)
ret = stack_chk_guard;
else
memcmp (&ret, (char *) dl_random + sizeof (ret), sizeof (ret));
return ret;
}
5 changes: 4 additions & 1 deletion sysdeps/generic/ldsodefs.h
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/* Run-time dynamic linker data structures for loaded ELF shared objects.
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
Expand Down Expand Up @@ -731,6 +731,9 @@ weak_extern (_dl_starting_up)
extern int _dl_starting_up_internal attribute_hidden;
#endif

/* Random data provided by the kernel. */
extern void *_dl_random attribute_hidden;

/* OS-dependent function to open the zero-fill device. */
extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */

Expand Down
56 changes: 43 additions & 13 deletions sysdeps/unix/sysv/linux/dl-osinfo.h
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/* Operating system specific code for generic dynamic loader functions. Linux.
Copyright (C) 2000-2002,2004-2007,2008 Free Software Foundation, Inc.
Copyright (C) 2000-2002,2004-2008, 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
Expand Down Expand Up @@ -60,22 +60,52 @@ dl_fatal (const char *str)
} while (0)

static inline uintptr_t __attribute__ ((always_inline))
_dl_setup_stack_chk_guard (void)
_dl_setup_stack_chk_guard (void *dl_random)
{
uintptr_t ret;
#ifdef ENABLE_STACKGUARD_RANDOMIZE
int fd = __open ("/dev/urandom", O_RDONLY);
if (fd >= 0)
#ifndef __ASSUME_AT_RANDOM
if (__builtin_expect (dl_random == NULL, 0))
{
ssize_t reslen = __read (fd, &ret, sizeof (ret));
__close (fd);
if (reslen == (ssize_t) sizeof (ret))
return ret;
# ifdef ENABLE_STACKGUARD_RANDOMIZE
int fd = __open ("/dev/urandom", O_RDONLY);
if (fd >= 0)
{
ssize_t reslen = __read (fd, &ret, sizeof (ret));
__close (fd);
if (reslen == (ssize_t) sizeof (ret))
return ret;
}
# endif
ret = 0;
unsigned char *p = (unsigned char *) &ret;
p[sizeof (ret) - 1] = 255;
p[sizeof (ret) - 2] = '\n';
}
else
#endif
ret = 0;
unsigned char *p = (unsigned char *) &ret;
p[sizeof (ret) - 1] = 255;
p[sizeof (ret) - 2] = '\n';
/* We need in the moment only 8 bytes on 32-bit platforms and 16
bytes on 64-bit platforms. Therefore we can use the data
directly and not use the kernel-provided data to seed a PRNG. */
memcpy (&ret, dl_random, sizeof (ret));
return ret;
}

static inline uintptr_t __attribute__ ((always_inline))
_dl_setup_pointer_guard (void *dl_random, uintptr_t stack_chk_guard)
{
uintptr_t ret;
#ifndef __ASSUME_AT_RANDOM
if (dl_random == NULL)
{
ret = stack_chk_guard;
# ifndef HP_TIMING_NONAVAIL
hp_timing_t now;
HP_TIMING_NOW (now);
ret ^= now;
# endif
}
else
#endif
memcpy (&ret, (char *) dl_random + sizeof (ret), sizeof (ret));
return ret;
}

0 comments on commit 965cb60

Please sign in to comment.