cregit-Linux how code gets into the kernel

Release 4.17 crypto/memneq.c

Directory: crypto
/*
 * Constant-time equality testing of memory regions.
 *
 * Authors:
 *
 *   James Yonan <james@openvpn.net>
 *   Daniel Borkmann <dborkman@redhat.com>
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2013 OpenVPN Technologies, Inc. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 * The full GNU General Public License is included in this distribution
 * in the file called LICENSE.GPL.
 *
 * BSD LICENSE
 *
 * Copyright(c) 2013 OpenVPN Technologies, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of OpenVPN Technologies nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <crypto/algapi.h>

#ifndef __HAVE_ARCH_CRYPTO_MEMNEQ

/* Generic path for arbitrary size */

static inline unsigned long __crypto_memneq_generic(const void *a, const void *b, size_t size) { unsigned long neq = 0; #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) while (size >= sizeof(unsigned long)) { neq |= *(unsigned long *)a ^ *(unsigned long *)b; OPTIMIZER_HIDE_VAR(neq); a += sizeof(unsigned long); b += sizeof(unsigned long); size -= sizeof(unsigned long); } #endif /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */ while (size > 0) { neq |= *(unsigned char *)a ^ *(unsigned char *)b; OPTIMIZER_HIDE_VAR(neq); a += 1; b += 1; size -= 1; } return neq; }

Contributors

PersonTokensPropCommitsCommitProp
James Yonan13192.91%150.00%
Cesar Eduardo Barros107.09%150.00%
Total141100.00%2100.00%

/* Loop-free fast-path for frequently used 16-byte size */
static inline unsigned long __crypto_memneq_16(const void *a, const void *b) { unsigned long neq = 0; #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS if (sizeof(unsigned long) == 8) { neq |= *(unsigned long *)(a) ^ *(unsigned long *)(b); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned long *)(a+8) ^ *(unsigned long *)(b+8); OPTIMIZER_HIDE_VAR(neq); } else if (sizeof(unsigned int) == 4) { neq |= *(unsigned int *)(a) ^ *(unsigned int *)(b); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned int *)(a+4) ^ *(unsigned int *)(b+4); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned int *)(a+8) ^ *(unsigned int *)(b+8); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned int *)(a+12) ^ *(unsigned int *)(b+12); OPTIMIZER_HIDE_VAR(neq); } else #endif /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */ { neq |= *(unsigned char *)(a) ^ *(unsigned char *)(b); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+1) ^ *(unsigned char *)(b+1); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+2) ^ *(unsigned char *)(b+2); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+3) ^ *(unsigned char *)(b+3); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+4) ^ *(unsigned char *)(b+4); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+5) ^ *(unsigned char *)(b+5); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+6) ^ *(unsigned char *)(b+6); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+7) ^ *(unsigned char *)(b+7); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+8) ^ *(unsigned char *)(b+8); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+9) ^ *(unsigned char *)(b+9); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+10) ^ *(unsigned char *)(b+10); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+11) ^ *(unsigned char *)(b+11); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+12) ^ *(unsigned char *)(b+12); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+13) ^ *(unsigned char *)(b+13); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+14) ^ *(unsigned char *)(b+14); OPTIMIZER_HIDE_VAR(neq); neq |= *(unsigned char *)(a+15) ^ *(unsigned char *)(b+15); OPTIMIZER_HIDE_VAR(neq); } return neq; }

Contributors

PersonTokensPropCommitsCommitProp
James Yonan54174.01%133.33%
Cesar Eduardo Barros18925.85%133.33%
Daniel Borkmann10.14%133.33%
Total731100.00%3100.00%

/* Compare two areas of memory without leaking timing information, * and with special optimizations for common sizes. Users should * not call this function directly, but should instead use * crypto_memneq defined in crypto/algapi.h. */
noinline unsigned long __crypto_memneq(const void *a, const void *b, size_t size) { switch (size) { case 16: return __crypto_memneq_16(a, b); default: return __crypto_memneq_generic(a, b, size); } }

Contributors

PersonTokensPropCommitsCommitProp
James Yonan48100.00%1100.00%
Total48100.00%1100.00%

EXPORT_SYMBOL(__crypto_memneq); #endif /* __HAVE_ARCH_CRYPTO_MEMNEQ */

Overall Contributors

PersonTokensPropCommitsCommitProp
James Yonan73878.68%133.33%
Cesar Eduardo Barros19921.22%133.33%
Daniel Borkmann10.11%133.33%
Total938100.00%3100.00%
Directory: crypto
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