/*
* 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 <asm/byteorder.h>
#include <linux/bitops.h>
#include <linux/crypto.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.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)))
*/
static inline u8 byte(const u32 x, const unsigned n)
{
return x >> (n << 3);
}
#define u32_in(x) le32_to_cpu(*(const __le32 *)(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 u8 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)])
static 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; \
}
static 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");
MODULE_ALIAS("aes");
