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

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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.
This commit is contained in:
Ulrich Drepper
2009-01-11 04:44:06 +00:00
parent 5b656a0d30
commit 965cb60a21
7 changed files with 112 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
sysdeps/unix/sysv/linux/dl-osinfo.h
View File

@ -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
@ -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;
}