aes_32.c
/*
*
* Glue Code for optimized 586 assembler version of AES
*
* Copyright (c) 2002, Dr Brian Gladman <>, 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.
*
* Copyright (c) 2003, Adam J. Richter <adam@yggdrasil.com> (conversion to
* 2.5 API).
* Copyright (c) 2003, 2004 Fruhwirth Clemens <clemens@endorphin.org>
* Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
*
*/
#include <asm/byteorder.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/linkage.h>
asmlinkage void aes_enc_blk(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
asmlinkage void aes_dec_blk(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
#define AES_MIN_KEY_SIZE 16
#define AES_MAX_KEY_SIZE 32
#define AES_BLOCK_SIZE 16
#define AES_KS_LENGTH 4 * AES_BLOCK_SIZE
#define RC_LENGTH 29
struct aes_ctx {
u32 ekey[AES_KS_LENGTH];
u32 rounds;
u32 dkey[AES_KS_LENGTH];
};
#define WPOLY 0x011b
#define bytes2word(b0, b1, b2, b3) \
(((u32)(b3) << 24) | ((u32)(b2) << 16) | ((u32)(b1) << 8) | (b0))
/* define the finite field multiplies required for Rijndael */
#define f2(x) ((x) ? pow[log[x] + 0x19] : 0)
#define f3(x) ((x) ? pow[log[x] + 0x01] : 0)
#define f9(x) ((x) ? pow[log[x] + 0xc7] : 0)
#define fb(x) ((x) ? pow[log[x] + 0x68] : 0)
#define fd(x) ((x) ? pow[log[x] + 0xee] : 0)
#define fe(x) ((x) ? pow[log[x] + 0xdf] : 0)
#define fi(x) ((x) ? pow[255 - log[x]]: 0)
static inline u32 upr(u32 x, int n)
{
return (x << 8 * n) | (x >> (32 - 8 * n));
}
static inline u8 bval(u32 x, int n)
{
return x >> 8 * n;
}
/* The forward and inverse affine transformations used in the S-box */
#define fwd_affine(x) \
(w = (u32)x, w ^= (w<<1)^(w<<2)^(w<<3)^(w<<4), 0x63^(u8)(w^(w>>8)))
#define inv_affine(x) \
(w = (u32)x, w = (w<<1)^(w<<3)^(w<<6), 0x05^(u8)(w^(w>>8)))
static u32 rcon_tab[RC_LENGTH];
u32 ft_tab[4][256];
u32 fl_tab[4][256];
static u32 im_tab[4][256];
u32 il_tab[4][256];
u32 it_tab[4][256];
static void gen_tabs(void)
{
u32 i, w;
u8 pow[512], log[256];
/*
* log and power tables for GF(2^8) finite field with
* WPOLY as modular polynomial - the simplest primitive
* root is 0x03, used here to generate the tables.
*/
i = 0; w = 1;
do {
pow[i] = (u8)w;
pow[i + 255] = (u8)w;
log[w] = (u8)i++;
w ^= (w << 1) ^ (w & 0x80 ? WPOLY : 0);
} while (w != 1);
for(i = 0, w = 1; i < RC_LENGTH; ++i) {
rcon_tab[i] = bytes2word(w, 0, 0, 0);
w = f2(w);
}
for(i = 0; i < 256; ++i) {
u8 b;
b = fwd_affine(fi((u8)i));
w = bytes2word(f2(b), b, b, f3(b));
/* tables for a normal encryption round */
ft_tab[0][i] = w;
ft_tab[1][i] = upr(w, 1);
ft_tab[2][i] = upr(w, 2);
ft_tab[3][i] = upr(w, 3);
w = bytes2word(b, 0, 0, 0);
/*
* tables for last encryption round
* (may also be used in the key schedule)
*/
fl_tab[0][i] = w;
fl_tab[1][i] = upr(w, 1);
fl_tab[2][i] = upr(w, 2);
fl_tab[3][i] = upr(w, 3);
b = fi(inv_affine((u8)i));
w = bytes2word(fe(b), f9(b), fd(b), fb(b));
/* tables for the inverse mix column operation */
im_tab[0][b] = w;
im_tab[1][b] = upr(w, 1);
im_tab[2][b] = upr(w, 2);
im_tab[3][b] = upr(w, 3);
/* tables for a normal decryption round */
it_tab[0][i] = w;
it_tab[1][i] = upr(w,1);
it_tab[2][i] = upr(w,2);
it_tab[3][i] = upr(w,3);
w = bytes2word(b, 0, 0, 0);
/* tables for last decryption round */
il_tab[0][i] = w;
il_tab[1][i] = upr(w,1);
il_tab[2][i] = upr(w,2);
il_tab[3][i] = upr(w,3);
}
}
#define four_tables(x,tab,vf,rf,c) \
( tab[0][bval(vf(x,0,c),rf(0,c))] ^ \
tab[1][bval(vf(x,1,c),rf(1,c))] ^ \
tab[2][bval(vf(x,2,c),rf(2,c))] ^ \
tab[3][bval(vf(x,3,c),rf(3,c))] \
)
#define vf1(x,r,c) (x)
#define rf1(r,c) (r)
#define rf2(r,c) ((r-c)&3)
#define inv_mcol(x) four_tables(x,im_tab,vf1,rf1,0)
#define ls_box(x,c) four_tables(x,fl_tab,vf1,rf2,c)
#define ff(x) inv_mcol(x)
#define ke4(k,i) \
{ \
k[4*(i)+4] = ss[0] ^= ls_box(ss[3],3) ^ rcon_tab[i]; \
k[4*(i)+5] = ss[1] ^= ss[0]; \
k[4*(i)+6] = ss[2] ^= ss[1]; \
k[4*(i)+7] = ss[3] ^= ss[2]; \
}
#define kel4(k,i) \
{ \
k[4*(i)+4] = ss[0] ^= ls_box(ss[3],3) ^ rcon_tab[i]; \
k[4*(i)+5] = ss[1] ^= ss[0]; \
k[4*(i)+6] = ss[2] ^= ss[1]; k[4*(i)+7] = ss[3] ^= ss[2]; \
}
#define ke6(k,i) \
{ \
k[6*(i)+ 6] = ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i]; \
k[6*(i)+ 7] = ss[1] ^= ss[0]; \
k[6*(i)+ 8] = ss[2] ^= ss[1]; \
k[6*(i)+ 9] = ss[3] ^= ss[2]; \
k[6*(i)+10] = ss[4] ^= ss[3]; \
k[6*(i)+11] = ss[5] ^= ss[4]; \
}
#define kel6(k,i) \
{ \
k[6*(i)+ 6] = ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i]; \
k[6*(i)+ 7] = ss[1] ^= ss[0]; \
k[6*(i)+ 8] = ss[2] ^= ss[1]; \
k[6*(i)+ 9] = ss[3] ^= ss[2]; \
}
#define ke8(k,i) \
{ \
k[8*(i)+ 8] = ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i]; \
k[8*(i)+ 9] = ss[1] ^= ss[0]; \
k[8*(i)+10] = ss[2] ^= ss[1]; \
k[8*(i)+11] = ss[3] ^= ss[2]; \
k[8*(i)+12] = ss[4] ^= ls_box(ss[3],0); \
k[8*(i)+13] = ss[5] ^= ss[4]; \
k[8*(i)+14] = ss[6] ^= ss[5]; \
k[8*(i)+15] = ss[7] ^= ss[6]; \
}
#define kel8(k,i) \
{ \
k[8*(i)+ 8] = ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i]; \
k[8*(i)+ 9] = ss[1] ^= ss[0]; \
k[8*(i)+10] = ss[2] ^= ss[1]; \
k[8*(i)+11] = ss[3] ^= ss[2]; \
}
#define kdf4(k,i) \
{ \
ss[0] = ss[0] ^ ss[2] ^ ss[1] ^ ss[3]; \
ss[1] = ss[1] ^ ss[3]; \
ss[2] = ss[2] ^ ss[3]; \
ss[3] = ss[3]; \
ss[4] = ls_box(ss[(i+3) % 4], 3) ^ rcon_tab[i]; \
ss[i % 4] ^= ss[4]; \
ss[4] ^= k[4*(i)]; \
k[4*(i)+4] = ff(ss[4]); \
ss[4] ^= k[4*(i)+1]; \
k[4*(i)+5] = ff(ss[4]); \
ss[4] ^= k[4*(i)+2]; \
k[4*(i)+6] = ff(ss[4]); \
ss[4] ^= k[4*(i)+3]; \
k[4*(i)+7] = ff(ss[4]); \
}
#define kd4(k,i) \
{ \
ss[4] = ls_box(ss[(i+3) % 4], 3) ^ rcon_tab[i]; \
ss[i % 4] ^= ss[4]; \
ss[4] = ff(ss[4]); \
k[4*(i)+4] = ss[4] ^= k[4*(i)]; \
k[4*(i)+5] = ss[4] ^= k[4*(i)+1]; \
k[4*(i)+6] = ss[4] ^= k[4*(i)+2]; \
k[4*(i)+7] = ss[4] ^= k[4*(i)+3]; \
}
#define kdl4(k,i) \
{ \
ss[4] = ls_box(ss[(i+3) % 4], 3) ^ rcon_tab[i]; \
ss[i % 4] ^= ss[4]; \
k[4*(i)+4] = (ss[0] ^= ss[1]) ^ ss[2] ^ ss[3]; \
k[4*(i)+5] = ss[1] ^ ss[3]; \
k[4*(i)+6] = ss[0]; \
k[4*(i)+7] = ss[1]; \
}
#define kdf6(k,i) \
{ \
ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i]; \
k[6*(i)+ 6] = ff(ss[0]); \
ss[1] ^= ss[0]; \
k[6*(i)+ 7] = ff(ss[1]); \
ss[2] ^= ss[1]; \
k[6*(i)+ 8] = ff(ss[2]); \
ss[3] ^= ss[2]; \
k[6*(i)+ 9] = ff(ss[3]); \
ss[4] ^= ss[3]; \
k[6*(i)+10] = ff(ss[4]); \
ss[5] ^= ss[4]; \
k[6*(i)+11] = ff(ss[5]); \
}
#define kd6(k,i) \
{ \
ss[6] = ls_box(ss[5],3) ^ rcon_tab[i]; \
ss[0] ^= ss[6]; ss[6] = ff(ss[6]); \
k[6*(i)+ 6] = ss[6] ^= k[6*(i)]; \
ss[1] ^= ss[0]; \
k[6*(i)+ 7] = ss[6] ^= k[6*(i)+ 1]; \
ss[2] ^= ss[1]; \
k[6*(i)+ 8] = ss[6] ^= k[6*(i)+ 2]; \
ss[3] ^= ss[2]; \
k[6*(i)+ 9] = ss[6] ^= k[6*(i)+ 3]; \
ss[4] ^= ss[3]; \
k[6*(i)+10] = ss[6] ^= k[6*(i)+ 4]; \
ss[5] ^= ss[4]; \
k[6*(i)+11] = ss[6] ^= k[6*(i)+ 5]; \
}
#define kdl6(k,i) \
{ \
ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i]; \
k[6*(i)+ 6] = ss[0]; \
ss[1] ^= ss[0]; \
k[6*(i)+ 7] = ss[1]; \
ss[2] ^= ss[1]; \
k[6*(i)+ 8] = ss[2]; \
ss[3] ^= ss[2]; \
k[6*(i)+ 9] = ss[3]; \
}
#define kdf8(k,i) \
{ \
ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i]; \
k[8*(i)+ 8] = ff(ss[0]); \
ss[1] ^= ss[0]; \
k[8*(i)+ 9] = ff(ss[1]); \
ss[2] ^= ss[1]; \
k[8*(i)+10] = ff(ss[2]); \
ss[3] ^= ss[2]; \
k[8*(i)+11] = ff(ss[3]); \
ss[4] ^= ls_box(ss[3],0); \
k[8*(i)+12] = ff(ss[4]); \
ss[5] ^= ss[4]; \
k[8*(i)+13] = ff(ss[5]); \
ss[6] ^= ss[5]; \
k[8*(i)+14] = ff(ss[6]); \
ss[7] ^= ss[6]; \
k[8*(i)+15] = ff(ss[7]); \
}
#define kd8(k,i) \
{ \
u32 __g = ls_box(ss[7],3) ^ rcon_tab[i]; \
ss[0] ^= __g; \
__g = ff(__g); \
k[8*(i)+ 8] = __g ^= k[8*(i)]; \
ss[1] ^= ss[0]; \
k[8*(i)+ 9] = __g ^= k[8*(i)+ 1]; \
ss[2] ^= ss[1]; \
k[8*(i)+10] = __g ^= k[8*(i)+ 2]; \
ss[3] ^= ss[2]; \
k[8*(i)+11] = __g ^= k[8*(i)+ 3]; \
__g = ls_box(ss[3],0); \
ss[4] ^= __g; \
__g = ff(__g); \
k[8*(i)+12] = __g ^= k[8*(i)+ 4]; \
ss[5] ^= ss[4]; \
k[8*(i)+13] = __g ^= k[8*(i)+ 5]; \
ss[6] ^= ss[5]; \
k[8*(i)+14] = __g ^= k[8*(i)+ 6]; \
ss[7] ^= ss[6]; \
k[8*(i)+15] = __g ^= k[8*(i)+ 7]; \
}
#define kdl8(k,i) \
{ \
ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i]; \
k[8*(i)+ 8] = ss[0]; \
ss[1] ^= ss[0]; \
k[8*(i)+ 9] = ss[1]; \
ss[2] ^= ss[1]; \
k[8*(i)+10] = ss[2]; \
ss[3] ^= ss[2]; \
k[8*(i)+11] = ss[3]; \
}
static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
int i;
u32 ss[8];
struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *key = (const __le32 *)in_key;
u32 *flags = &tfm->crt_flags;
/* encryption schedule */
ctx->ekey[0] = ss[0] = le32_to_cpu(key[0]);
ctx->ekey[1] = ss[1] = le32_to_cpu(key[1]);
ctx->ekey[2] = ss[2] = le32_to_cpu(key[2]);
ctx->ekey[3] = ss[3] = le32_to_cpu(key[3]);
switch(key_len) {
case 16:
for (i = 0; i < 9; i++)
ke4(ctx->ekey, i);
kel4(ctx->ekey, 9);
ctx->rounds = 10;
break;
case 24:
ctx->ekey[4] = ss[4] = le32_to_cpu(key[4]);
ctx->ekey[5] = ss[5] = le32_to_cpu(key[5]);
for (i = 0; i < 7; i++)
ke6(ctx->ekey, i);
kel6(ctx->ekey, 7);
ctx->rounds = 12;
break;
case 32:
ctx->ekey[4] = ss[4] = le32_to_cpu(key[4]);
ctx->ekey[5] = ss[5] = le32_to_cpu(key[5]);
ctx->ekey[6] = ss[6] = le32_to_cpu(key[6]);
ctx->ekey[7] = ss[7] = le32_to_cpu(key[7]);
for (i = 0; i < 6; i++)
ke8(ctx->ekey, i);
kel8(ctx->ekey, 6);
ctx->rounds = 14;
break;
default:
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
/* decryption schedule */
ctx->dkey[0] = ss[0] = le32_to_cpu(key[0]);
ctx->dkey[1] = ss[1] = le32_to_cpu(key[1]);
ctx->dkey[2] = ss[2] = le32_to_cpu(key[2]);
ctx->dkey[3] = ss[3] = le32_to_cpu(key[3]);
switch (key_len) {
case 16:
kdf4(ctx->dkey, 0);
for (i = 1; i < 9; i++)
kd4(ctx->dkey, i);
kdl4(ctx->dkey, 9);
break;
case 24:
ctx->dkey[4] = ff(ss[4] = le32_to_cpu(key[4]));
ctx->dkey[5] = ff(ss[5] = le32_to_cpu(key[5]));
kdf6(ctx->dkey, 0);
for (i = 1; i < 7; i++)
kd6(ctx->dkey, i);
kdl6(ctx->dkey, 7);
break;
case 32:
ctx->dkey[4] = ff(ss[4] = le32_to_cpu(key[4]));
ctx->dkey[5] = ff(ss[5] = le32_to_cpu(key[5]));
ctx->dkey[6] = ff(ss[6] = le32_to_cpu(key[6]));
ctx->dkey[7] = ff(ss[7] = le32_to_cpu(key[7]));
kdf8(ctx->dkey, 0);
for (i = 1; i < 6; i++)
kd8(ctx->dkey, i);
kdl8(ctx->dkey, 6);
break;
}
return 0;
}
static void aes_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
aes_enc_blk(tfm, dst, src);
}
static void aes_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
aes_dec_blk(tfm, dst, src);
}
static struct crypto_alg aes_alg = {
.cra_name = "aes",
.cra_driver_name = "aes-i586",
.cra_priority = 200,
.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, i586 asm optimized");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Fruhwirth Clemens, James Morris, Brian Gladman, Adam Richter");
MODULE_ALIAS("aes");
