1 /* Copyright (c) (2014,2015,2019) Apple Inc. All rights reserved.
2 *
3 * corecrypto is licensed under Apple Inc.’s Internal Use License Agreement (which
4 * is contained in the License.txt file distributed with corecrypto) and only to
5 * people who accept that license. IMPORTANT: Any license rights granted to you by
6 * Apple Inc. (if any) are limited to internal use within your organization only on
7 * devices and computers you own or control, for the sole purpose of verifying the
8 * security characteristics and correct functioning of the Apple Software. You may
9 * not, directly or indirectly, redistribute the Apple Software or any portions thereof.
10 *
11 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
12 *
13 * This file contains Original Code and/or Modifications of Original Code
14 * as defined in and that are subject to the Apple Public Source License
15 * Version 2.0 (the 'License'). You may not use this file except in
16 * compliance with the License. The rights granted to you under the License
17 * may not be used to create, or enable the creation or redistribution of,
18 * unlawful or unlicensed copies of an Apple operating system, or to
19 * circumvent, violate, or enable the circumvention or violation of, any
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21 *
22 * Please obtain a copy of the License at
23 * http://www.opensource.apple.com/apsl/ and read it before using this file.
24 *
25 * The Original Code and all software distributed under the License are
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30 * Please see the License for the specific language governing rights and
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34 */
35
36 #include "cc_internal.h"
37 #include <corecrypto/cc_priv.h>
38
39 int
cc_cmp_safe(size_t num,const void * ptr1,const void * ptr2)40 cc_cmp_safe(size_t num, const void * ptr1, const void * ptr2)
41 {
42 CC_ENSURE_DIT_ENABLED
43
44 size_t i;
45 const uint8_t *s = (const uint8_t *)ptr1;
46 const uint8_t *t = (const uint8_t *)ptr2;
47 uint8_t flag = ((num <= 0)?1:0); // If 0 return an error
48 for (i = 0; i < num; i++) {
49 flag |= (s[i] ^ t[i]);
50 }
51 CC_HEAVISIDE_STEP(flag, flag); // flag=(flag==0)?0:1;
52 return flag; // 0 iff all bytes were equal, 1 if there is any difference
53 }
54