[RFC][PATCH 2/4] AES assembler implementation for x86_64

[Andreas Steinmetz <ast@domdv.de>]

The attached patch contains Gladman's in-kernel code for key schedule
and table generation modified to fit to my assembler implementation,
-- 
Andreas Steinmetz                       SPAMmers use robotrap@domdv.de

diff -rNu linux-2.6.11.2.orig/arch/x86_64/crypto/aes.c linux-2.6.11.2/arch/x86_64/crypto/aes.c
--- linux-2.6.11.2.orig/arch/x86_64/crypto/aes.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.11.2/arch/x86_64/crypto/aes.c	2005-04-17 13:34:17.000000000 +0200
@@ -0,0 +1,332 @@
+/* 
+ * Cryptographic API.
+ *
+ * AES Cipher Algorithm.
+ *
+ * Based on Brian Gladman's code.
+ *
+ * Linux developers:
+ *  Alexander Kjeldaas <astor@fast.no>
+ *  Herbert Valerio Riedel <hvr@hvrlab.org>
+ *  Kyle McMartin <kyle@debian.org>
+ *  Adam J. Richter <adam@yggdrasil.com> (conversion to 2.5 API).
+ *  Andreas Steinmetz <ast@domdv.de> (adapted to x86_64 assembler)
+ *
+ * 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.
+ *
+ * ---------------------------------------------------------------------------
+ * Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
+ * All rights reserved.
+ *
+ * LICENSE TERMS
+ *
+ * The free distribution and use of this software in both source and binary
+ * form is allowed (with or without changes) provided that:
+ *
+ *   1. distributions of this source code include the above copyright
+ *      notice, this list of conditions and the following disclaimer;
+ *
+ *   2. distributions in binary form include the above copyright
+ *      notice, this list of conditions and the following disclaimer
+ *      in the documentation and/or other associated materials;
+ *
+ *   3. the copyright holder's name is not used to endorse products
+ *      built using this software without specific written permission.
+ *
+ * ALTERNATIVELY, provided that this notice is retained in full, this product
+ * may be distributed under the terms of the GNU General Public License (GPL),
+ * in which case the provisions of the GPL apply INSTEAD OF those given above.
+ *
+ * DISCLAIMER
+ *
+ * This software is provided 'as is' with no explicit or implied warranties
+ * in respect of its properties, including, but not limited to, correctness
+ * and/or fitness for purpose.
+ * ---------------------------------------------------------------------------
+ */
+
+/* Some changes from the Gladman version:
+    s/RIJNDAEL(e_key)/E_KEY/g
+    s/RIJNDAEL(d_key)/D_KEY/g
+*/
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/crypto.h>
+#include <asm/byteorder.h>
+
+#define AES_MIN_KEY_SIZE	16
+#define AES_MAX_KEY_SIZE	32
+
+#define AES_BLOCK_SIZE		16
+
+/*
+ * #define byte(x, nr) ((unsigned char)((x) >> (nr*8))) 
+ */
+inline static u8
+byte(const u32 x, const unsigned n)
+{
+	return x >> (n << 3);
+}
+
+#define u32_in(x) le32_to_cpu(*(const u32 *)(x))
+
+struct aes_ctx {
+	u32 key_length;
+	u32 E[60];
+	u32 D[60];
+};
+
+#define E_KEY ctx->E
+#define D_KEY ctx->D
+
+static u8 pow_tab[256] __initdata;
+static u8 log_tab[256] __initdata;
+static u8 sbx_tab[256] __initdata;
+static u8 isb_tab[256] __initdata;
+static u32 rco_tab[10];
+u32 aes_ft_tab[4][256];
+u32 aes_it_tab[4][256];
+
+u32 aes_fl_tab[4][256];
+u32 aes_il_tab[4][256];
+
+static inline u32 __init rol32(u32 word, unsigned int shift)
+{
+	return (word << shift) | (word >> (32 - shift));
+}
+
+static inline u32 ror32(u32 word, unsigned int shift)
+{
+	return (word >> shift) | (word << (32 - shift));
+}
+
+static inline u8 __init
+f_mult (u8 a, u8 b)
+{
+	u8 aa = log_tab[a], cc = aa + log_tab[b];
+
+	return pow_tab[cc + (cc < aa ? 1 : 0)];
+}
+
+#define ff_mult(a,b)    (a && b ? f_mult(a, b) : 0)
+
+#define ls_box(x)				\
+    ( aes_fl_tab[0][byte(x, 0)] ^		\
+      aes_fl_tab[1][byte(x, 1)] ^		\
+      aes_fl_tab[2][byte(x, 2)] ^		\
+      aes_fl_tab[3][byte(x, 3)] )
+
+void __init
+gen_tabs (void)
+{
+	u32 i, t;
+	u8 p, q;
+
+	/* log and power tables for GF(2**8) finite field with
+	   0x011b as modular polynomial - the simplest primitive
+	   root is 0x03, used here to generate the tables */
+
+	for (i = 0, p = 1; i < 256; ++i) {
+		pow_tab[i] = (u8) p;
+		log_tab[p] = (u8) i;
+
+		p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
+	}
+
+	log_tab[1] = 0;
+
+	for (i = 0, p = 1; i < 10; ++i) {
+		rco_tab[i] = p;
+
+		p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
+	}
+
+	for (i = 0; i < 256; ++i) {
+		p = (i ? pow_tab[255 - log_tab[i]] : 0);
+		q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
+		p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
+		sbx_tab[i] = p;
+		isb_tab[p] = (u8) i;
+	}
+
+	for (i = 0; i < 256; ++i) {
+		p = sbx_tab[i];
+
+		t = p;
+		aes_fl_tab[0][i] = t;
+		aes_fl_tab[1][i] = rol32(t, 8);
+		aes_fl_tab[2][i] = rol32(t, 16);
+		aes_fl_tab[3][i] = rol32(t, 24);
+
+		t = ((u32) ff_mult (2, p)) |
+		    ((u32) p << 8) |
+		    ((u32) p << 16) | ((u32) ff_mult (3, p) << 24);
+
+		aes_ft_tab[0][i] = t;
+		aes_ft_tab[1][i] = rol32(t, 8);
+		aes_ft_tab[2][i] = rol32(t, 16);
+		aes_ft_tab[3][i] = rol32(t, 24);
+
+		p = isb_tab[i];
+
+		t = p;
+		aes_il_tab[0][i] = t;
+		aes_il_tab[1][i] = rol32(t, 8);
+		aes_il_tab[2][i] = rol32(t, 16);
+		aes_il_tab[3][i] = rol32(t, 24);
+
+		t = ((u32) ff_mult (14, p)) |
+		    ((u32) ff_mult (9, p) << 8) |
+		    ((u32) ff_mult (13, p) << 16) |
+		    ((u32) ff_mult (11, p) << 24);
+
+		aes_it_tab[0][i] = t;
+		aes_it_tab[1][i] = rol32(t, 8);
+		aes_it_tab[2][i] = rol32(t, 16);
+		aes_it_tab[3][i] = rol32(t, 24);
+	}
+}
+
+#define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
+
+#define imix_col(y,x)       \
+    u   = star_x(x);        \
+    v   = star_x(u);        \
+    w   = star_x(v);        \
+    t   = w ^ (x);          \
+   (y)  = u ^ v ^ w;        \
+   (y) ^= ror32(u ^ t,  8) ^ \
+          ror32(v ^ t, 16) ^ \
+          ror32(t,24)
+
+/* initialise the key schedule from the user supplied key */
+
+#define loop4(i)                                    \
+{   t = ror32(t,  8); t = ls_box(t) ^ rco_tab[i];    \
+    t ^= E_KEY[4 * i];     E_KEY[4 * i + 4] = t;    \
+    t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t;    \
+    t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t;    \
+    t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t;    \
+}
+
+#define loop6(i)                                    \
+{   t = ror32(t,  8); t = ls_box(t) ^ rco_tab[i];    \
+    t ^= E_KEY[6 * i];     E_KEY[6 * i + 6] = t;    \
+    t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t;    \
+    t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t;    \
+    t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t;    \
+    t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t;   \
+    t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t;   \
+}
+
+#define loop8(i)                                    \
+{   t = ror32(t,  8); ; t = ls_box(t) ^ rco_tab[i];  \
+    t ^= E_KEY[8 * i];     E_KEY[8 * i + 8] = t;    \
+    t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t;    \
+    t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t;   \
+    t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t;   \
+    t  = E_KEY[8 * i + 4] ^ ls_box(t);    \
+    E_KEY[8 * i + 12] = t;                \
+    t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t;   \
+    t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t;   \
+    t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t;   \
+}
+
+int
+aes_set_key(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags)
+{
+	struct aes_ctx *ctx = ctx_arg;
+	u32 i, j, t, u, v, w;
+
+	if (key_len != 16 && key_len != 24 && key_len != 32) {
+		*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+
+	ctx->key_length = key_len;
+
+	D_KEY[key_len + 24] = E_KEY[0] = u32_in (in_key);
+	D_KEY[key_len + 25] = E_KEY[1] = u32_in (in_key + 4);
+	D_KEY[key_len + 26] = E_KEY[2] = u32_in (in_key + 8);
+	D_KEY[key_len + 27] = E_KEY[3] = u32_in (in_key + 12);
+
+	switch (key_len) {
+	case 16:
+		t = E_KEY[3];
+		for (i = 0; i < 10; ++i)
+			loop4 (i);
+		break;
+
+	case 24:
+		E_KEY[4] = u32_in (in_key + 16);
+		t = E_KEY[5] = u32_in (in_key + 20);
+		for (i = 0; i < 8; ++i)
+			loop6 (i);
+		break;
+
+	case 32:
+		E_KEY[4] = u32_in (in_key + 16);
+		E_KEY[5] = u32_in (in_key + 20);
+		E_KEY[6] = u32_in (in_key + 24);
+		t = E_KEY[7] = u32_in (in_key + 28);
+		for (i = 0; i < 7; ++i)
+			loop8 (i);
+		break;
+	}
+
+	D_KEY[0] = E_KEY[key_len + 24];
+	D_KEY[1] = E_KEY[key_len + 25];
+	D_KEY[2] = E_KEY[key_len + 26];
+	D_KEY[3] = E_KEY[key_len + 27];
+
+	for (i = 4; i < key_len + 24; ++i) {
+		j = key_len + 24 - (i & ~3) + (i & 3);
+		imix_col (D_KEY[j], E_KEY[i]);
+	}
+
+	return 0;
+}
+
+extern void aes_encrypt(void *ctx_arg, u8 *out, const u8 *in);
+extern void aes_decrypt(void *ctx_arg, u8 *out, const u8 *in);
+
+static struct crypto_alg aes_alg = {
+	.cra_name		=	"aes",
+	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize		=	AES_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct aes_ctx),
+	.cra_module		=	THIS_MODULE,
+	.cra_list		=	LIST_HEAD_INIT(aes_alg.cra_list),
+	.cra_u			=	{
+		.cipher = {
+			.cia_min_keysize	=	AES_MIN_KEY_SIZE,
+			.cia_max_keysize	=	AES_MAX_KEY_SIZE,
+			.cia_setkey	   	= 	aes_set_key,
+			.cia_encrypt	 	=	aes_encrypt,
+			.cia_decrypt	  	=	aes_decrypt
+		}
+	}
+};
+
+static int __init aes_init(void)
+{
+	gen_tabs();
+	return crypto_register_alg(&aes_alg);
+}
+
+static void __exit aes_fini(void)
+{
+	crypto_unregister_alg(&aes_alg);
+}
+
+module_init(aes_init);
+module_exit(aes_fini);
+
+MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
+MODULE_LICENSE("GPL");