Torne (Richard Coles) | 5821806 | 2012-11-14 11:43:16 +0000 | [diff] [blame] | 1 | /* ***** BEGIN LICENSE BLOCK ***** |
| 2 | * Version: MPL 1.1/GPL 2.0/LGPL 2.1 |
| 3 | * |
| 4 | * The contents of this file are subject to the Mozilla Public License Version |
| 5 | * 1.1 (the "License"); you may not use this file except in compliance with |
| 6 | * the License. You may obtain a copy of the License at |
| 7 | * http://www.mozilla.org/MPL/ |
| 8 | * |
| 9 | * Software distributed under the License is distributed on an "AS IS" basis, |
| 10 | * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License |
| 11 | * for the specific language governing rights and limitations under the |
| 12 | * License. |
| 13 | * |
| 14 | * The Original Code is the Netscape security libraries. |
| 15 | * |
| 16 | * The Initial Developer of the Original Code is |
| 17 | * Netscape Communications Corporation. |
| 18 | * Portions created by the Initial Developer are Copyright (C) 1994-2000 |
| 19 | * the Initial Developer. All Rights Reserved. |
| 20 | * |
| 21 | * Contributor(s): |
| 22 | * |
| 23 | * Alternatively, the contents of this file may be used under the terms of |
| 24 | * either the GNU General Public License Version 2 or later (the "GPL"), or |
| 25 | * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), |
| 26 | * in which case the provisions of the GPL or the LGPL are applicable instead |
| 27 | * of those above. If you wish to allow use of your version of this file only |
| 28 | * under the terms of either the GPL or the LGPL, and not to allow others to |
| 29 | * use your version of this file under the terms of the MPL, indicate your |
| 30 | * decision by deleting the provisions above and replace them with the notice |
| 31 | * and other provisions required by the GPL or the LGPL. If you do not delete |
| 32 | * the provisions above, a recipient may use your version of this file under |
| 33 | * the terms of any one of the MPL, the GPL or the LGPL. |
| 34 | * |
| 35 | * ***** END LICENSE BLOCK ***** */ |
| 36 | |
| 37 | // This file exists to provide the secure memcmp function. This was added in |
| 38 | // NSS 3.12.5. |
| 39 | |
| 40 | #include <stdlib.h> |
| 41 | |
| 42 | /* |
| 43 | * Perform a constant-time compare of two memory regions. The return value is |
| 44 | * 0 if the memory regions are equal and non-zero otherwise. |
| 45 | */ |
| 46 | int |
| 47 | NSS_SecureMemcmp(const void *ia, const void *ib, size_t n) |
| 48 | { |
| 49 | const unsigned char *a = (const unsigned char*) ia; |
| 50 | const unsigned char *b = (const unsigned char*) ib; |
| 51 | size_t i; |
| 52 | unsigned char r = 0; |
| 53 | |
| 54 | for (i = 0; i < n; ++i) { |
| 55 | r |= *a++ ^ *b++; |
| 56 | } |
| 57 | |
| 58 | return r; |
| 59 | } |