crypto: memneq - move into lib/

This is used by code that doesn't need CONFIG_CRYPTO, so move this into
lib/ with a Kconfig option so that it can be selected by whatever needs
it.

This fixes a linker error Zheng pointed out when
CRYPTO_MANAGER_DISABLE_TESTS!=y and CRYPTO=m:

  lib/crypto/curve25519-selftest.o: In function `curve25519_selftest':
  curve25519-selftest.c:(.init.text+0x60): undefined reference to `__crypto_memneq'
  curve25519-selftest.c:(.init.text+0xec): undefined reference to `__crypto_memneq'
  curve25519-selftest.c:(.init.text+0x114): undefined reference to `__crypto_memneq'
  curve25519-selftest.c:(.init.text+0x154): undefined reference to `__crypto_memneq'

Reported-by: Zheng Bin <zhengbin13@huawei.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: stable@vger.kernel.org
Fixes: aa127963f1ca ("crypto: lib/curve25519 - re-add selftests")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

3 files changed, 2 insertions, 177 deletions

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 9b654984de79..6e30e8138057 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -15,6 +15,7 @@ source "crypto/async_tx/Kconfig"
 #
 menuconfig CRYPTO
 	tristate "Cryptographic API"
+	select LIB_MEMNEQ
 	help
 	  This option provides the core Cryptographic API.
 
diff --git a/crypto/Makefile b/crypto/Makefile
index 3bbc0dd49160..1f529704fe80 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -4,7 +4,7 @@
 #
 
 obj-$(CONFIG_CRYPTO) += crypto.o
-crypto-y := api.o cipher.o compress.o memneq.o
+crypto-y := api.o cipher.o compress.o
 
 obj-$(CONFIG_CRYPTO_ENGINE) += crypto_engine.o
 obj-$(CONFIG_CRYPTO_FIPS) += fips.o
diff --git a/crypto/memneq.c b/crypto/memneq.c
deleted file mode 100644
index fb11608b1ec1..000000000000
--- a/crypto/memneq.c
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * 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>
-#include <asm/unaligned.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 |= get_unaligned((unsigned long *)a) ^
-		       get_unaligned((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;
-}
-
-/* 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 |= get_unaligned((unsigned long *)a) ^
-		       get_unaligned((unsigned long *)b);
-		OPTIMIZER_HIDE_VAR(neq);
-		neq |= get_unaligned((unsigned long *)(a + 8)) ^
-		       get_unaligned((unsigned long *)(b + 8));
-		OPTIMIZER_HIDE_VAR(neq);
-	} else if (sizeof(unsigned int) == 4) {
-		neq |= get_unaligned((unsigned int *)a) ^
-		       get_unaligned((unsigned int *)b);
-		OPTIMIZER_HIDE_VAR(neq);
-		neq |= get_unaligned((unsigned int *)(a + 4)) ^
-		       get_unaligned((unsigned int *)(b + 4));
-		OPTIMIZER_HIDE_VAR(neq);
-		neq |= get_unaligned((unsigned int *)(a + 8)) ^
-		       get_unaligned((unsigned int *)(b + 8));
-		OPTIMIZER_HIDE_VAR(neq);
-		neq |= get_unaligned((unsigned int *)(a + 12)) ^
-		       get_unaligned((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;
-}
-
-/* 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);
-	}
-}
-EXPORT_SYMBOL(__crypto_memneq);
-
-#endif /* __HAVE_ARCH_CRYPTO_MEMNEQ */