94 lines
2.1 KiB
C
94 lines
2.1 KiB
C
/* $OpenBSD: subr_poison.c,v 1.15 2022/08/14 01:58:28 jsg Exp $ */
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/*
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* Copyright (c) 2013 Ted Unangst <tedu@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <sys/param.h>
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/*
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* The POISON is used as known text to copy into free objects so
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* that modifications after frees can be detected.
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*/
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#ifdef DEADBEEF0
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#define POISON0 ((unsigned) DEADBEEF0)
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#else
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#define POISON0 ((unsigned) 0xdeadbeef)
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#endif
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#ifdef DEADBEEF1
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#define POISON1 ((unsigned) DEADBEEF1)
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#else
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#define POISON1 ((unsigned) 0xdeafbead)
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#endif
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#define POISON_SIZE 64
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uint32_t
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poison_value(void *v)
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{
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ulong l = (u_long)v;
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l = l >> PAGE_SHIFT;
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switch (l & 3) {
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case 0:
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return POISON0;
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case 1:
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return POISON1;
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case 2:
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return (POISON0 & 0xffff0000) | (~POISON0 & 0x0000ffff);
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case 3:
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return (POISON1 & 0xffff0000) | (~POISON1 & 0x0000ffff);
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}
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return 0;
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}
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void
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poison_mem(void *v, size_t len)
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{
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uint32_t *ip = v;
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size_t i;
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uint32_t poison;
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poison = poison_value(v);
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if (len > POISON_SIZE)
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len = POISON_SIZE;
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len = len / sizeof(*ip);
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for (i = 0; i < len; i++)
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ip[i] = poison;
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}
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int
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poison_check(void *v, size_t len, size_t *pidx, uint32_t *pval)
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{
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uint32_t *ip = v;
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size_t i;
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uint32_t poison;
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poison = poison_value(v);
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if (len > POISON_SIZE)
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len = POISON_SIZE;
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len = len / sizeof(*ip);
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for (i = 0; i < len; i++) {
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if (ip[i] != poison) {
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*pidx = i;
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*pval = poison;
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return 1;
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}
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}
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return 0;
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}
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