0887c9463f
Wrapper for realloc() that checks for overflow when multiplying arguments together, so we don't have to add overflow checks to every single call. For documentation on usage, see: http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man3/calloc.3 Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com> Acked-by: Matt Turner <mattst88@gmail.com>
44 lines
1.4 KiB
C
44 lines
1.4 KiB
C
/* $OpenBSD: reallocarray.c,v 1.2 2014/12/08 03:45:00 bcook Exp $ */
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/*
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* Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
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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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#ifdef HAVE_DIX_CONFIG_H
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#include <dix-config.h>
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#endif
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#include <sys/types.h>
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#include <errno.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include "os.h"
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/*
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* This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
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* if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
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*/
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#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
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void *
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reallocarray(void *optr, size_t nmemb, size_t size)
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{
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if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
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nmemb > 0 && SIZE_MAX / nmemb < size) {
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errno = ENOMEM;
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return NULL;
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}
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return realloc(optr, size * nmemb);
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}
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