stack_protector.c   [plain text]


/*
 * Copyright (c) 2008 Apple Computer, Inc. All rights reserved.
 *
 * %Begin-Header%
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 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, and the entire permission notice in its entirety,
 *    including the disclaimer of warranties.
 * 2. 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.
 * 3. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR 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
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 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 * %End-Header%
 */

/*******************************************************************************
* NOTE: This implementation of the stack check routines required by the GCC
* -fstack-protector flag is only safe for kernel extensions.
*******************************************************************************/

#include <sys/types.h>
#include <sys/random.h>
#include <kern/debug.h>

long __stack_chk_guard[8];
void __stack_chk_fail(void);

static void __guard_setup(void) __attribute__((constructor));

static void
__guard_setup(void)
{
    /* Cannot report failure.  */
    read_random(__stack_chk_guard, sizeof(__stack_chk_guard));
}

void
__stack_chk_fail(void)
{
    panic("Kernel stack memory corruption detected");
}