Re: [PATCH 3/4] Twofish cipher - i586 assembler

From: Joachim Fritschi
Date: Sat Jun 17 2006 - 06:30:13 EST


After recieving some more feedback from linux@xxxxxxxxxxx, i have revised my
patch a bit and done some cosmetic changes. The first_round macros are now
eliminated and the pop instruction has been moved forward a bit.

The patch passed the trycpt tests and automated filesystem tests.


Signed-off-by: Joachim Fritschi <jfritschi@xxxxxxxxxx>

diff -uprN linux-2.6.17-rc5.twofish2/arch/i386/crypto/Makefile linux-2.6.17-rc5.twofish3/arch/i386/crypto/Makefile
--- linux-2.6.17-rc5.twofish2/arch/i386/crypto/Makefile 2006-06-11 15:58:36.991988374 +0200
+++ linux-2.6.17-rc5.twofish3/arch/i386/crypto/Makefile 2006-06-11 16:05:51.675813834 +0200
@@ -5,5 +5,8 @@
#

obj-$(CONFIG_CRYPTO_AES_586) += aes-i586.o
+obj-$(CONFIG_CRYPTO_TWOFISH_586) += twofish-i586.o

aes-i586-y := aes-i586-asm.o aes.o
+twofish-i586-y := twofish-i586-asm.o twofish.o
+
diff -uprN linux-2.6.17-rc5.twofish2/arch/i386/crypto/twofish.c linux-2.6.17-rc5.twofish3/arch/i386/crypto/twofish.c
--- linux-2.6.17-rc5.twofish2/arch/i386/crypto/twofish.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.17-rc5.twofish3/arch/i386/crypto/twofish.c 2006-06-11 16:03:56.669852049 +0200
@@ -0,0 +1,88 @@
+/*
+ * Glue Code for optimized 586 assembler version of TWOFISH
+ *
+ * Originally Twofish for GPG
+ * By Matthew Skala <mskala@xxxxxxxxxxxxxxxxx>, July 26, 1998
+ * 256-bit key length added March 20, 1999
+ * Some modifications to reduce the text size by Werner Koch, April, 1998
+ * Ported to the kerneli patch by Marc Mutz <Marc@xxxxxxxx>
+ * Ported to CryptoAPI by Colin Slater <hoho@xxxxxxxxxxxx>
+ *
+ * The original author has disclaimed all copyright interest in this
+ * code and thus put it in the public domain. The subsequent authors
+ * have put this under the GNU General Public License.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
+ *
+ * This code is a "clean room" implementation, written from the paper
+ * _Twofish: A 128-Bit Block Cipher_ by Bruce Schneier, John Kelsey,
+ * Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson, available
+ * through http://www.counterpane.com/twofish.html
+ *
+ * For background information on multiplication in finite fields, used for
+ * the matrix operations in the key schedule, see the book _Contemporary
+ * Abstract Algebra_ by Joseph A. Gallian, especially chapter 22 in the
+ * Third Edition.
+ */
+
+#include <asm/byteorder.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/crypto.h>
+#include <linux/bitops.h>
+#include <crypto/twofish.h>
+
+
+asmlinkage void twofish_enc_blk(void *ctx, u8 *dst, const u8 *src);
+
+asmlinkage void twofish_dec_blk(void *ctx, u8 *dst, const u8 *src);
+
+
+static struct crypto_alg alg = {
+ .cra_name = "twofish",
+ .cra_driver_name = "twofish-i586",
+ .cra_priority = 200,
+ .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
+ .cra_blocksize = TF_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct twofish_ctx),
+ .cra_alignmask = 3,
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(alg.cra_list),
+ .cra_u = { .cipher = {
+ .cia_min_keysize = TF_MIN_KEY_SIZE,
+ .cia_max_keysize = TF_MAX_KEY_SIZE,
+ .cia_setkey = twofish_setkey,
+ .cia_encrypt = twofish_enc_blk,
+ .cia_decrypt = twofish_dec_blk } }
+};
+
+static int __init init(void)
+{
+ return crypto_register_alg(&alg);
+}
+
+static void __exit fini(void)
+{
+ crypto_unregister_alg(&alg);
+}
+
+module_init(init);
+module_exit(fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION ("Twofish Cipher Algorithm, i586 asm optimized");
diff -uprN linux-2.6.17-rc5.twofish2/arch/i386/crypto/twofish-i586-asm.S linux-2.6.17-rc5.twofish3/arch/i386/crypto/twofish-i586-asm.S
--- linux-2.6.17-rc5.twofish2/arch/i386/crypto/twofish-i586-asm.S 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.17-rc5.twofish3/arch/i386/crypto/twofish-i586-asm.S 2006-06-17 11:08:32.536993468 +0200
@@ -0,0 +1,331 @@
+/***************************************************************************
+* Copyright (C) 2006 by Joachim Fritschi, <jfritschi@xxxxxxxxxx> *
+* *
+* This program is free software; you can redistribute it and/or modify *
+* it under the terms of the GNU General Public License as published by *
+* the Free Software Foundation; either version 2 of the License, or *
+* (at your option) any later version. *
+* *
+* 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., *
+* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
+***************************************************************************/
+
+.file "twofish-i586-asm.S"
+.text
+
+/* return adress at 0 */
+
+#define in_blk 12 /* input byte array address parameter*/
+#define out_blk 8 /* output byte array address parameter*/
+#define ctx 4 /* Twofish context structure */
+
+#define a_offset 0
+#define b_offset 4
+#define c_offset 8
+#define d_offset 12
+
+/* Structure of the crypto context struct*/
+
+#define s0 0 /* S0 Array 256 Words each */
+#define s1 1024 /* S1 Array */
+#define s2 2048 /* S2 Array */
+#define s3 3072 /* S3 Array */
+#define w 4096 /* 8 whitening keys (word) */
+#define k 4128 /* key 1-32 ( word ) */
+
+/* define a few register aliases to allow macro substitution */
+
+#define R0D %eax
+#define R0B %al
+#define R0H %ah
+
+#define R1D %ebx
+#define R1B %bl
+#define R1H %bh
+
+#define R2D %ecx
+#define R2B %cl
+#define R2H %ch
+
+#define R3D %edx
+#define R3B %dl
+#define R3H %dh
+
+
+/* performs input whitening */
+#define input_whitening(src,context,offset)\
+ xor w+offset(context), src;
+
+/* performs input whitening */
+#define output_whitening(src,context,offset)\
+ xor w+16+offset(context), src;
+
+/*
+a input register containing a (rotated 16)
+b input register containing b
+c input register containing c
+d input register containing d (already rol $1)
+operations on a and b are interleaved to increase performance
+*/
+#define encrypt_round(a,b,c,d,round)\
+push d ## D;\
+movzx b ## B, %edi;\
+mov s1(%ebp,%edi,4),d ## D;\
+movzx a ## B, %edi;\
+mov s2(%ebp,%edi,4),%esi;\
+movzx b ## H, %edi;\
+ror $16, b ## D;\
+xor s2(%ebp,%edi,4),d ## D;\
+movzx a ## H, %edi;\
+ror $16, a ## D;\
+xor s3(%ebp,%edi,4),%esi;\
+movzx b ## B, %edi;\
+xor s3(%ebp,%edi,4),d ## D;\
+movzx a ## B, %edi;\
+xor (%ebp,%edi,4), %esi;\
+movzx b ## H, %edi;\
+ror $15, b ## D;\
+xor (%ebp,%edi,4), d ## D;\
+movzx a ## H, %edi;\
+xor s1(%ebp,%edi,4),%esi;\
+pop %edi;\
+add d ## D, %esi;\
+add %esi, d ## D;\
+add k+round(%ebp), %esi;\
+xor %esi, c ## D;\
+rol $15, c ## D;\
+add k+4+round(%ebp),d ## D;\
+xor %edi, d ## D;
+
+/*
+a input register containing a (rotated 16)
+b input register containing b
+c input register containing c
+d input register containing d (already rol $1)
+operations on a and b are interleaved to increase performance
+last round has different rotations for the output preparation
+*/
+#define encrypt_last_round(a,b,c,d,round)\
+push d ## D;\
+movzx b ## B, %edi;\
+mov s1(%ebp,%edi,4),d ## D;\
+movzx a ## B, %edi;\
+mov s2(%ebp,%edi,4),%esi;\
+movzx b ## H, %edi;\
+ror $16, b ## D;\
+xor s2(%ebp,%edi,4),d ## D;\
+movzx a ## H, %edi;\
+ror $16, a ## D;\
+xor s3(%ebp,%edi,4),%esi;\
+movzx b ## B, %edi;\
+xor s3(%ebp,%edi,4),d ## D;\
+movzx a ## B, %edi;\
+xor (%ebp,%edi,4), %esi;\
+movzx b ## H, %edi;\
+ror $16, b ## D;\
+xor (%ebp,%edi,4), d ## D;\
+movzx a ## H, %edi;\
+xor s1(%ebp,%edi,4),%esi;\
+pop %edi;\
+add d ## D, %esi;\
+add %esi, d ## D;\
+add k+round(%ebp), %esi;\
+xor %esi, c ## D;\
+ror $1, c ## D;\
+add k+4+round(%ebp),d ## D;\
+xor %edi, d ## D;
+
+/*
+a input register containing a
+b input register containing b (rotated 16)
+c input register containing c
+d input register containing d (already rol $1)
+operations on a and b are interleaved to increase performance
+*/
+#define decrypt_round(a,b,c,d,round)\
+push c ## D;\
+movzx a ## B, %edi;\
+mov (%ebp,%edi,4), c ## D;\
+movzx b ## B, %edi;\
+mov s3(%ebp,%edi,4),%esi;\
+movzx a ## H, %edi;\
+ror $16, a ## D;\
+xor s1(%ebp,%edi,4),c ## D;\
+movzx b ## H, %edi;\
+ror $16, b ## D;\
+xor (%ebp,%edi,4), %esi;\
+movzx a ## B, %edi;\
+xor s2(%ebp,%edi,4),c ## D;\
+movzx b ## B, %edi;\
+xor s1(%ebp,%edi,4),%esi;\
+movzx a ## H, %edi;\
+ror $15, a ## D;\
+xor s3(%ebp,%edi,4),c ## D;\
+movzx b ## H, %edi;\
+xor s2(%ebp,%edi,4),%esi;\
+pop %edi;\
+add %esi, c ## D;\
+add c ## D, %esi;\
+add k+round(%ebp), c ## D;\
+xor %edi, c ## D;\
+add k+4+round(%ebp),%esi;\
+xor %esi, d ## D;\
+rol $15, d ## D;
+
+/*
+a input register containing a
+b input register containing b (rotated 16)
+c input register containing c
+d input register containing d (already rol $1)
+operations on a and b are interleaved to increase performance
+last round has different rotations for the output preparation
+*/
+#define decrypt_last_round(a,b,c,d,round)\
+push c ## D;\
+movzx a ## B, %edi;\
+mov (%ebp,%edi,4), c ## D;\
+movzx b ## B, %edi;\
+mov s3(%ebp,%edi,4),%esi;\
+movzx a ## H, %edi;\
+ror $16, a ## D;\
+xor s1(%ebp,%edi,4),c ## D;\
+movzx b ## H, %edi;\
+ror $16, b ## D;\
+xor (%ebp,%edi,4), %esi;\
+movzx a ## B, %edi;\
+xor s2(%ebp,%edi,4),c ## D;\
+movzx b ## B, %edi;\
+xor s1(%ebp,%edi,4),%esi;\
+movzx a ## H, %edi;\
+ror $16, a ## D;\
+xor s3(%ebp,%edi,4),c ## D;\
+movzx b ## H, %edi;\
+xor s2(%ebp,%edi,4),%esi;\
+pop %edi;\
+add %esi, c ## D;\
+add c ## D, %esi;\
+add k+round(%ebp), c ## D;\
+xor %edi, c ## D;\
+add k+4+round(%ebp),%esi;\
+xor %esi, d ## D;\
+ror $1, d ## D;
+
+.align 4
+.global twofish_enc_blk
+.global twofish_dec_blk
+
+twofish_enc_blk:
+ push %ebp /* save registers according to calling convention*/
+ push %ebx
+ push %esi
+ push %edi
+
+ mov ctx + 16(%esp), %ebp /* abuse the base pointer: set new base bointer to the crypto ctx */
+ mov in_blk+16(%esp),%edi /* input adress in edi */
+
+ mov (%edi), %eax
+ mov b_offset(%edi), %ebx
+ mov c_offset(%edi), %ecx
+ mov d_offset(%edi), %edx
+ input_whitening(%eax,%ebp,a_offset)
+ ror $16, %eax
+ input_whitening(%ebx,%ebp,b_offset)
+ input_whitening(%ecx,%ebp,c_offset)
+ input_whitening(%edx,%ebp,d_offset)
+ rol $1, %edx
+
+ encrypt_round(R0,R1,R2,R3,0);
+ encrypt_round(R2,R3,R0,R1,8);
+ encrypt_round(R0,R1,R2,R3,2*8);
+ encrypt_round(R2,R3,R0,R1,3*8);
+ encrypt_round(R0,R1,R2,R3,4*8);
+ encrypt_round(R2,R3,R0,R1,5*8);
+ encrypt_round(R0,R1,R2,R3,6*8);
+ encrypt_round(R2,R3,R0,R1,7*8);
+ encrypt_round(R0,R1,R2,R3,8*8);
+ encrypt_round(R2,R3,R0,R1,9*8);
+ encrypt_round(R0,R1,R2,R3,10*8);
+ encrypt_round(R2,R3,R0,R1,11*8);
+ encrypt_round(R0,R1,R2,R3,12*8);
+ encrypt_round(R2,R3,R0,R1,13*8);
+ encrypt_round(R0,R1,R2,R3,14*8);
+ encrypt_last_round(R2,R3,R0,R1,15*8);
+
+ output_whitening(%eax,%ebp,c_offset)
+ output_whitening(%ebx,%ebp,d_offset)
+ output_whitening(%ecx,%ebp,a_offset)
+ output_whitening(%edx,%ebp,b_offset)
+ mov out_blk+16(%esp),%edi;
+ mov %eax, c_offset(%edi)
+ mov %ebx, d_offset(%edi)
+ mov %ecx, (%edi)
+ mov %edx, b_offset(%edi)
+
+ pop %edi
+ pop %esi
+ pop %ebx
+ pop %ebp
+ mov $1, %eax
+ ret
+
+twofish_dec_blk:
+ push %ebp /* save registers according to calling convention*/
+ push %ebx
+ push %esi
+ push %edi
+
+
+ mov ctx + 16(%esp), %ebp /* abuse the base pointer: set new base bointer to the crypto ctx */
+ mov in_blk+16(%esp),%edi /* input adress in edi */
+
+ mov (%edi), %eax
+ mov b_offset(%edi), %ebx
+ mov c_offset(%edi), %ecx
+ mov d_offset(%edi), %edx
+ output_whitening(%eax,%ebp,a_offset)
+ output_whitening(%ebx,%ebp,b_offset)
+ ror $16, %ebx
+ output_whitening(%ecx,%ebp,c_offset)
+ output_whitening(%edx,%ebp,d_offset)
+ rol $1, %ecx
+
+ decrypt_round(R0,R1,R2,R3,15*8);
+ decrypt_round(R2,R3,R0,R1,14*8);
+ decrypt_round(R0,R1,R2,R3,13*8);
+ decrypt_round(R2,R3,R0,R1,12*8);
+ decrypt_round(R0,R1,R2,R3,11*8);
+ decrypt_round(R2,R3,R0,R1,10*8);
+ decrypt_round(R0,R1,R2,R3,9*8);
+ decrypt_round(R2,R3,R0,R1,8*8);
+ decrypt_round(R0,R1,R2,R3,7*8);
+ decrypt_round(R2,R3,R0,R1,6*8);
+ decrypt_round(R0,R1,R2,R3,5*8);
+ decrypt_round(R2,R3,R0,R1,4*8);
+ decrypt_round(R0,R1,R2,R3,3*8);
+ decrypt_round(R2,R3,R0,R1,2*8);
+ decrypt_round(R0,R1,R2,R3,1*8);
+ decrypt_last_round(R2,R3,R0,R1,0);
+
+ input_whitening(%eax,%ebp,c_offset)
+ input_whitening(%ebx,%ebp,d_offset)
+ input_whitening(%ecx,%ebp,a_offset)
+ input_whitening(%edx,%ebp,b_offset)
+ mov out_blk+16(%esp),%edi;
+ mov %eax, c_offset(%edi)
+ mov %ebx, d_offset(%edi)
+ mov %ecx, (%edi)
+ mov %edx, b_offset(%edi)
+
+ pop %edi
+ pop %esi
+ pop %ebx
+ pop %ebp
+ mov $1, %eax
+ ret
diff -uprN linux-2.6.17-rc5.twofish2/crypto/Kconfig linux-2.6.17-rc5.twofish3/crypto/Kconfig
--- linux-2.6.17-rc5.twofish2/crypto/Kconfig 2006-06-11 15:58:39.219982140 +0200
+++ linux-2.6.17-rc5.twofish3/crypto/Kconfig 2006-06-11 16:05:19.938782275 +0200
@@ -150,6 +150,21 @@ config CRYPTO_TWOFISH_COMMON
Common parts of the Twofish cipher algorithm.


+config CRYPTO_TWOFISH_586
+ tristate "Twofish cipher algorithms (i586)"
+ depends on CRYPTO && ((X86 || UML_X86) && !64BIT)
+ select CRYPTO_TWOFISH_COMMON
+ help
+ Twofish cipher algorithm.
+
+ Twofish was submitted as an AES (Advanced Encryption Standard)
+ candidate cipher by researchers at CounterPane Systems. It is a
+ 16 round block cipher supporting key sizes of 128, 192, and 256
+ bits.
+
+ See also:
+ <http://www.schneier.com/twofish.html>
+
config CRYPTO_SERPENT
tristate "Serpent cipher algorithm"
depends on CRYPTO
-
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