77 lines
2.4 KiB
C
77 lines
2.4 KiB
C
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/*
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* Copyright (C) 2012 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _PRIVATE_SSP_H
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#define _PRIVATE_SSP_H
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#include <errno.h>
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#include <sys/cdefs.h>
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__BEGIN_DECLS
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/** WARNING WARNING WARNING
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**
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** This header file is *NOT* part of the public Bionic ABI/API
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** and should not be used/included by user-serviceable parts of
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** the system (e.g. applications).
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**/
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/* GCC uses this on ARM and MIPS. */
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extern void* __stack_chk_guard;
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/* GCC calls this if a stack guard check fails. */
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extern void __stack_chk_fail();
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__inline__ static void* __attribute__((always_inline)) __generate_stack_chk_guard(void) {
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union {
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uintptr_t value;
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char bytes[sizeof(uintptr_t)];
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} u;
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/* Try pulling random bytes from /dev/urandom. */
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int fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY));
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if (fd != -1) {
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ssize_t byte_count = TEMP_FAILURE_RETRY(read(fd, &u.bytes, sizeof(u)));
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close(fd);
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if (byte_count == sizeof(u)) {
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return (void*) u.value;
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}
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}
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/* If that failed, switch to 'terminator canary'. */
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u.bytes[0] = 0;
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u.bytes[1] = 0;
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u.bytes[2] = '\n';
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u.bytes[3] = 255;
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return (void*) u.value;
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}
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__END_DECLS
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#endif
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