e3a49a8661
Populate the stack canaries from the kernel supplied AT_RANDOM value, which doesn't involve any system calls. This is slightly faster (6 fewer syscalls) and avoids unnecessarily reading /dev/urandom, which depletes entropy. Bug: 7959813 Change-Id: If2b43100a2a9929666df3de56b6139fed969e0f1
61 lines
2.0 KiB
C
61 lines
2.0 KiB
C
/*
|
|
* Copyright (C) 2012 The Android Open Source Project
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* * Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* * Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
|
|
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#ifndef _PRIVATE_SSP_H
|
|
#define _PRIVATE_SSP_H
|
|
|
|
#include <string.h>
|
|
#include <sys/auxv.h>
|
|
|
|
__BEGIN_DECLS
|
|
|
|
/** WARNING WARNING WARNING
|
|
**
|
|
** This header file is *NOT* part of the public Bionic ABI/API
|
|
** and should not be used/included by user-serviceable parts of
|
|
** the system (e.g. applications).
|
|
**/
|
|
|
|
/* GCC uses this on ARM and MIPS. */
|
|
extern void* __stack_chk_guard;
|
|
|
|
/* GCC calls this if a stack guard check fails. */
|
|
extern void __stack_chk_fail();
|
|
|
|
__inline__ static void* __attribute__((always_inline)) __generate_stack_chk_guard(void) {
|
|
|
|
void* src = (void*) getauxval(AT_RANDOM);
|
|
void* result;
|
|
memcpy(&result, src, sizeof(result));
|
|
return result;
|
|
}
|
|
|
|
__END_DECLS
|
|
|
|
#endif
|