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linux/crypto/aes_generic.c
Sebastian Siewior f8246af005 [CRYPTO] aes: Rename aes to aes-generic 
Loading the crypto algorithm by the alias instead of by module directly
has the advantage that all possible implementations of this algorithm
are loaded automatically and the crypto API can choose the best one
depending on its priority.

Additionally it ensures that the generic implementation as well as the
HW driver (if available) is loaded in case the HW driver needs the
generic version as fallback in corner cases.

Signed-off-by: Sebastian Siewior <sebastian@breakpoint.cc>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-10-10 16:55:49 -07:00

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/*
* 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).
*
* 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)))
*/
static inline u8
byte(const u32 x, const unsigned n)
{
return x >> (n << 3);
}
struct aes_ctx {
int key_length;
u32 buf[120];
};
#define E_KEY (&ctx->buf[0])
#define D_KEY (&ctx->buf[60])
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];
static u32 ft_tab[4][256];
static u32 it_tab[4][256];
static u32 fl_tab[4][256];
static u32 il_tab[4][256];
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 f_rn(bo, bi, n, k) \
bo[n] = ft_tab[0][byte(bi[n],0)] ^ \
ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \
ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
#define i_rn(bo, bi, n, k) \
bo[n] = it_tab[0][byte(bi[n],0)] ^ \
it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \
it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
#define ls_box(x) \
( fl_tab[0][byte(x, 0)] ^ \
fl_tab[1][byte(x, 1)] ^ \
fl_tab[2][byte(x, 2)] ^ \
fl_tab[3][byte(x, 3)] )
#define f_rl(bo, bi, n, k) \
bo[n] = fl_tab[0][byte(bi[n],0)] ^ \
fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \
fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
#define i_rl(bo, bi, n, k) \
bo[n] = il_tab[0][byte(bi[n],0)] ^ \
il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \
il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
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;
fl_tab[0][i] = t;
fl_tab[1][i] = rol32(t, 8);
fl_tab[2][i] = rol32(t, 16);
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);
ft_tab[0][i] = t;
ft_tab[1][i] = rol32(t, 8);
ft_tab[2][i] = rol32(t, 16);
ft_tab[3][i] = rol32(t, 24);
p = isb_tab[i];
t = p;
il_tab[0][i] = t;
il_tab[1][i] = rol32(t, 8);
il_tab[2][i] = rol32(t, 16);
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);
it_tab[0][i] = t;
it_tab[1][i] = rol32(t, 8);
it_tab[2][i] = rol32(t, 16);
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(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *key = (const __le32 *)in_key;
u32 *flags = &tfm->crt_flags;
u32 i, t, u, v, w;
if (key_len % 8) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
ctx->key_length = key_len;
E_KEY[0] = le32_to_cpu(key[0]);
E_KEY[1] = le32_to_cpu(key[1]);
E_KEY[2] = le32_to_cpu(key[2]);
E_KEY[3] = le32_to_cpu(key[3]);
switch (key_len) {
case 16:
t = E_KEY[3];
for (i = 0; i < 10; ++i)
loop4 (i);
break;
case 24:
E_KEY[4] = le32_to_cpu(key[4]);
t = E_KEY[5] = le32_to_cpu(key[5]);
for (i = 0; i < 8; ++i)
loop6 (i);
break;
case 32:
E_KEY[4] = le32_to_cpu(key[4]);
E_KEY[5] = le32_to_cpu(key[5]);
E_KEY[6] = le32_to_cpu(key[6]);
t = E_KEY[7] = le32_to_cpu(key[7]);
for (i = 0; i < 7; ++i)
loop8 (i);
break;
}
D_KEY[0] = E_KEY[0];
D_KEY[1] = E_KEY[1];
D_KEY[2] = E_KEY[2];
D_KEY[3] = E_KEY[3];
for (i = 4; i < key_len + 24; ++i) {
imix_col (D_KEY[i], E_KEY[i]);
}
return 0;
}
/* encrypt a block of text */
#define f_nround(bo, bi, k) \
f_rn(bo, bi, 0, k); \
f_rn(bo, bi, 1, k); \
f_rn(bo, bi, 2, k); \
f_rn(bo, bi, 3, k); \
k += 4
#define f_lround(bo, bi, k) \
f_rl(bo, bi, 0, k); \
f_rl(bo, bi, 1, k); \
f_rl(bo, bi, 2, k); \
f_rl(bo, bi, 3, k)
static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
const struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *src = (const __le32 *)in;
__le32 *dst = (__le32 *)out;
u32 b0[4], b1[4];
const u32 *kp = E_KEY + 4;
b0[0] = le32_to_cpu(src[0]) ^ E_KEY[0];
b0[1] = le32_to_cpu(src[1]) ^ E_KEY[1];
b0[2] = le32_to_cpu(src[2]) ^ E_KEY[2];
b0[3] = le32_to_cpu(src[3]) ^ E_KEY[3];
if (ctx->key_length > 24) {
f_nround (b1, b0, kp);
f_nround (b0, b1, kp);
}
if (ctx->key_length > 16) {
f_nround (b1, b0, kp);
f_nround (b0, b1, kp);
}
f_nround (b1, b0, kp);
f_nround (b0, b1, kp);
f_nround (b1, b0, kp);
f_nround (b0, b1, kp);
f_nround (b1, b0, kp);
f_nround (b0, b1, kp);
f_nround (b1, b0, kp);
f_nround (b0, b1, kp);
f_nround (b1, b0, kp);
f_lround (b0, b1, kp);
dst[0] = cpu_to_le32(b0[0]);
dst[1] = cpu_to_le32(b0[1]);
dst[2] = cpu_to_le32(b0[2]);
dst[3] = cpu_to_le32(b0[3]);
}
/* decrypt a block of text */
#define i_nround(bo, bi, k) \
i_rn(bo, bi, 0, k); \
i_rn(bo, bi, 1, k); \
i_rn(bo, bi, 2, k); \
i_rn(bo, bi, 3, k); \
k -= 4
#define i_lround(bo, bi, k) \
i_rl(bo, bi, 0, k); \
i_rl(bo, bi, 1, k); \
i_rl(bo, bi, 2, k); \
i_rl(bo, bi, 3, k)
static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
const struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *src = (const __le32 *)in;
__le32 *dst = (__le32 *)out;
u32 b0[4], b1[4];
const int key_len = ctx->key_length;
const u32 *kp = D_KEY + key_len + 20;
b0[0] = le32_to_cpu(src[0]) ^ E_KEY[key_len + 24];
b0[1] = le32_to_cpu(src[1]) ^ E_KEY[key_len + 25];
b0[2] = le32_to_cpu(src[2]) ^ E_KEY[key_len + 26];
b0[3] = le32_to_cpu(src[3]) ^ E_KEY[key_len + 27];
if (key_len > 24) {
i_nround (b1, b0, kp);
i_nround (b0, b1, kp);
}
if (key_len > 16) {
i_nround (b1, b0, kp);
i_nround (b0, b1, kp);
}
i_nround (b1, b0, kp);
i_nround (b0, b1, kp);
i_nround (b1, b0, kp);
i_nround (b0, b1, kp);
i_nround (b1, b0, kp);
i_nround (b0, b1, kp);
i_nround (b1, b0, kp);
i_nround (b0, b1, kp);
i_nround (b1, b0, kp);
i_lround (b0, b1, kp);
dst[0] = cpu_to_le32(b0[0]);
dst[1] = cpu_to_le32(b0[1]);
dst[2] = cpu_to_le32(b0[2]);
dst[3] = cpu_to_le32(b0[3]);
}
static struct crypto_alg aes_alg = {
.cra_name = "aes",
.cra_driver_name = "aes-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct aes_ctx),
.cra_alignmask = 3,
.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("Dual BSD/GPL");
MODULE_ALIAS("aes");
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