mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-30 08:40:07 +00:00
115 lines
3.5 KiB
C
115 lines
3.5 KiB
C
/* Operating system specific code for generic dynamic loader functions. Linux.
|
|
Copyright (C) 2000-2013 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
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <kernel-features.h>
|
|
#include <dl-sysdep.h>
|
|
#include <endian.h>
|
|
#include <fcntl.h>
|
|
#include <stdint.h>
|
|
#include <not-cancel.h>
|
|
|
|
#ifndef MIN
|
|
# define MIN(a,b) (((a)<(b))?(a):(b))
|
|
#endif
|
|
|
|
#define DL_SYSDEP_OSCHECK(FATAL) \
|
|
do { \
|
|
/* Test whether the kernel is new enough. This test is only performed \
|
|
if the library is not compiled to run on all kernels. */ \
|
|
\
|
|
int version = _dl_discover_osversion (); \
|
|
if (__builtin_expect (version >= 0, 1)) \
|
|
{ \
|
|
if (__builtin_expect (GLRO(dl_osversion) == 0, 1) \
|
|
|| GLRO(dl_osversion) > version) \
|
|
GLRO(dl_osversion) = version; \
|
|
\
|
|
/* Now we can test with the required version. */ \
|
|
if (__LINUX_KERNEL_VERSION > 0 && version < __LINUX_KERNEL_VERSION) \
|
|
/* Not sufficent. */ \
|
|
FATAL ("FATAL: kernel too old\n"); \
|
|
} \
|
|
else if (__LINUX_KERNEL_VERSION > 0) \
|
|
FATAL ("FATAL: cannot determine kernel version\n"); \
|
|
} while (0)
|
|
|
|
static inline uintptr_t __attribute__ ((always_inline))
|
|
_dl_setup_stack_chk_guard (void *dl_random)
|
|
{
|
|
union
|
|
{
|
|
uintptr_t num;
|
|
unsigned char bytes[sizeof (uintptr_t)];
|
|
} ret;
|
|
|
|
#ifndef __ASSUME_AT_RANDOM
|
|
if (__builtin_expect (dl_random == NULL, 0))
|
|
{
|
|
const size_t filllen = sizeof (ret.bytes) - 1;
|
|
ret.num = 0;
|
|
# ifdef ENABLE_STACKGUARD_RANDOMIZE
|
|
int fd = open_not_cancel_2 ("/dev/urandom", O_RDONLY);
|
|
if (fd >= 0)
|
|
{
|
|
ssize_t reslen = read_not_cancel (fd, ret.bytes + 1, filllen);
|
|
close_not_cancel_no_status (fd);
|
|
if (reslen == (ssize_t) filllen)
|
|
return ret.num;
|
|
}
|
|
# endif
|
|
ret.bytes[filllen] = 255;
|
|
ret.bytes[filllen - 1] = '\n';
|
|
}
|
|
else
|
|
#endif
|
|
{
|
|
/* 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.bytes, dl_random, sizeof (ret));
|
|
#if BYTE_ORDER == LITTLE_ENDIAN
|
|
ret.num &= ~(uintptr_t) 0xff;
|
|
#elif BYTE_ORDER == BIG_ENDIAN
|
|
ret.num &= ~((uintptr_t) 0xff << (8 * (sizeof (ret) - 1)));
|
|
#else
|
|
# error "BYTE_ORDER unknown"
|
|
#endif
|
|
}
|
|
return ret.num;
|
|
}
|
|
|
|
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;
|
|
}
|