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Andreas Steinmetza2a892a2005-07-06 13:55:00 -07001/*
2 * Cryptographic API.
3 *
4 * AES Cipher Algorithm.
5 *
6 * Based on Brian Gladman's code.
7 *
8 * Linux developers:
9 * Alexander Kjeldaas <astor@fast.no>
10 * Herbert Valerio Riedel <hvr@hvrlab.org>
11 * Kyle McMartin <kyle@debian.org>
12 * Adam J. Richter <adam@yggdrasil.com> (conversion to 2.5 API).
13 * Andreas Steinmetz <ast@domdv.de> (adapted to x86_64 assembler)
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 *
20 * ---------------------------------------------------------------------------
21 * Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
22 * All rights reserved.
23 *
24 * LICENSE TERMS
25 *
26 * The free distribution and use of this software in both source and binary
27 * form is allowed (with or without changes) provided that:
28 *
29 * 1. distributions of this source code include the above copyright
30 * notice, this list of conditions and the following disclaimer;
31 *
32 * 2. distributions in binary form include the above copyright
33 * notice, this list of conditions and the following disclaimer
34 * in the documentation and/or other associated materials;
35 *
36 * 3. the copyright holder's name is not used to endorse products
37 * built using this software without specific written permission.
38 *
39 * ALTERNATIVELY, provided that this notice is retained in full, this product
40 * may be distributed under the terms of the GNU General Public License (GPL),
41 * in which case the provisions of the GPL apply INSTEAD OF those given above.
42 *
43 * DISCLAIMER
44 *
45 * This software is provided 'as is' with no explicit or implied warranties
46 * in respect of its properties, including, but not limited to, correctness
47 * and/or fitness for purpose.
48 * ---------------------------------------------------------------------------
49 */
50
51/* Some changes from the Gladman version:
52 s/RIJNDAEL(e_key)/E_KEY/g
53 s/RIJNDAEL(d_key)/D_KEY/g
54*/
55
56#include <asm/byteorder.h>
57#include <linux/bitops.h>
58#include <linux/crypto.h>
59#include <linux/errno.h>
60#include <linux/init.h>
61#include <linux/module.h>
62#include <linux/types.h>
63
64#define AES_MIN_KEY_SIZE 16
65#define AES_MAX_KEY_SIZE 32
66
67#define AES_BLOCK_SIZE 16
68
69/*
70 * #define byte(x, nr) ((unsigned char)((x) >> (nr*8)))
71 */
72static inline u8 byte(const u32 x, const unsigned n)
73{
74 return x >> (n << 3);
75}
76
77#define u32_in(x) le32_to_cpu(*(const __le32 *)(x))
78
79struct aes_ctx
80{
81 u32 key_length;
82 u32 E[60];
83 u32 D[60];
84};
85
86#define E_KEY ctx->E
87#define D_KEY ctx->D
88
89static u8 pow_tab[256] __initdata;
90static u8 log_tab[256] __initdata;
91static u8 sbx_tab[256] __initdata;
92static u8 isb_tab[256] __initdata;
93static u32 rco_tab[10];
94u32 aes_ft_tab[4][256];
95u32 aes_it_tab[4][256];
96
97u32 aes_fl_tab[4][256];
98u32 aes_il_tab[4][256];
99
100static inline u8 f_mult(u8 a, u8 b)
101{
102 u8 aa = log_tab[a], cc = aa + log_tab[b];
103
104 return pow_tab[cc + (cc < aa ? 1 : 0)];
105}
106
107#define ff_mult(a, b) (a && b ? f_mult(a, b) : 0)
108
109#define ls_box(x) \
110 (aes_fl_tab[0][byte(x, 0)] ^ \
111 aes_fl_tab[1][byte(x, 1)] ^ \
112 aes_fl_tab[2][byte(x, 2)] ^ \
113 aes_fl_tab[3][byte(x, 3)])
114
115static void __init gen_tabs(void)
116{
117 u32 i, t;
118 u8 p, q;
119
120 /* log and power tables for GF(2**8) finite field with
121 0x011b as modular polynomial - the simplest primitive
122 root is 0x03, used here to generate the tables */
123
124 for (i = 0, p = 1; i < 256; ++i) {
125 pow_tab[i] = (u8)p;
126 log_tab[p] = (u8)i;
127
128 p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
129 }
130
131 log_tab[1] = 0;
132
133 for (i = 0, p = 1; i < 10; ++i) {
134 rco_tab[i] = p;
135
136 p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
137 }
138
139 for (i = 0; i < 256; ++i) {
140 p = (i ? pow_tab[255 - log_tab[i]] : 0);
141 q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
142 p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
143 sbx_tab[i] = p;
144 isb_tab[p] = (u8)i;
145 }
146
147 for (i = 0; i < 256; ++i) {
148 p = sbx_tab[i];
149
150 t = p;
151 aes_fl_tab[0][i] = t;
152 aes_fl_tab[1][i] = rol32(t, 8);
153 aes_fl_tab[2][i] = rol32(t, 16);
154 aes_fl_tab[3][i] = rol32(t, 24);
155
156 t = ((u32)ff_mult(2, p)) |
157 ((u32)p << 8) |
158 ((u32)p << 16) | ((u32)ff_mult(3, p) << 24);
159
160 aes_ft_tab[0][i] = t;
161 aes_ft_tab[1][i] = rol32(t, 8);
162 aes_ft_tab[2][i] = rol32(t, 16);
163 aes_ft_tab[3][i] = rol32(t, 24);
164
165 p = isb_tab[i];
166
167 t = p;
168 aes_il_tab[0][i] = t;
169 aes_il_tab[1][i] = rol32(t, 8);
170 aes_il_tab[2][i] = rol32(t, 16);
171 aes_il_tab[3][i] = rol32(t, 24);
172
173 t = ((u32)ff_mult(14, p)) |
174 ((u32)ff_mult(9, p) << 8) |
175 ((u32)ff_mult(13, p) << 16) |
176 ((u32)ff_mult(11, p) << 24);
177
178 aes_it_tab[0][i] = t;
179 aes_it_tab[1][i] = rol32(t, 8);
180 aes_it_tab[2][i] = rol32(t, 16);
181 aes_it_tab[3][i] = rol32(t, 24);
182 }
183}
184
185#define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
186
187#define imix_col(y, x) \
188 u = star_x(x); \
189 v = star_x(u); \
190 w = star_x(v); \
191 t = w ^ (x); \
192 (y) = u ^ v ^ w; \
193 (y) ^= ror32(u ^ t, 8) ^ \
194 ror32(v ^ t, 16) ^ \
195 ror32(t, 24)
196
197/* initialise the key schedule from the user supplied key */
198
199#define loop4(i) \
200{ \
201 t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \
202 t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \
203 t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \
204 t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \
205 t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \
206}
207
208#define loop6(i) \
209{ \
210 t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \
211 t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \
212 t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \
213 t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \
214 t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \
215 t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \
216 t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \
217}
218
219#define loop8(i) \
220{ \
221 t = ror32(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \
222 t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \
223 t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \
224 t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \
225 t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \
226 t = E_KEY[8 * i + 4] ^ ls_box(t); \
227 E_KEY[8 * i + 12] = t; \
228 t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \
229 t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \
230 t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \
231}
232
233static int aes_set_key(void *ctx_arg, const u8 *in_key, unsigned int key_len,
234 u32 *flags)
235{
236 struct aes_ctx *ctx = ctx_arg;
237 u32 i, j, t, u, v, w;
238
239 if (key_len != 16 && key_len != 24 && key_len != 32) {
240 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
241 return -EINVAL;
242 }
243
244 ctx->key_length = key_len;
245
246 D_KEY[key_len + 24] = E_KEY[0] = u32_in(in_key);
247 D_KEY[key_len + 25] = E_KEY[1] = u32_in(in_key + 4);
248 D_KEY[key_len + 26] = E_KEY[2] = u32_in(in_key + 8);
249 D_KEY[key_len + 27] = E_KEY[3] = u32_in(in_key + 12);
250
251 switch (key_len) {
252 case 16:
253 t = E_KEY[3];
254 for (i = 0; i < 10; ++i)
255 loop4(i);
256 break;
257
258 case 24:
259 E_KEY[4] = u32_in(in_key + 16);
260 t = E_KEY[5] = u32_in(in_key + 20);
261 for (i = 0; i < 8; ++i)
262 loop6 (i);
263 break;
264
265 case 32:
266 E_KEY[4] = u32_in(in_key + 16);
267 E_KEY[5] = u32_in(in_key + 20);
268 E_KEY[6] = u32_in(in_key + 24);
269 t = E_KEY[7] = u32_in(in_key + 28);
270 for (i = 0; i < 7; ++i)
271 loop8(i);
272 break;
273 }
274
275 D_KEY[0] = E_KEY[key_len + 24];
276 D_KEY[1] = E_KEY[key_len + 25];
277 D_KEY[2] = E_KEY[key_len + 26];
278 D_KEY[3] = E_KEY[key_len + 27];
279
280 for (i = 4; i < key_len + 24; ++i) {
281 j = key_len + 24 - (i & ~3) + (i & 3);
282 imix_col(D_KEY[j], E_KEY[i]);
283 }
284
285 return 0;
286}
287
288extern void aes_encrypt(void *ctx_arg, u8 *out, const u8 *in);
289extern void aes_decrypt(void *ctx_arg, u8 *out, const u8 *in);
290
291static struct crypto_alg aes_alg = {
292 .cra_name = "aes",
293 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
294 .cra_blocksize = AES_BLOCK_SIZE,
295 .cra_ctxsize = sizeof(struct aes_ctx),
296 .cra_module = THIS_MODULE,
297 .cra_list = LIST_HEAD_INIT(aes_alg.cra_list),
298 .cra_u = {
299 .cipher = {
300 .cia_min_keysize = AES_MIN_KEY_SIZE,
301 .cia_max_keysize = AES_MAX_KEY_SIZE,
302 .cia_setkey = aes_set_key,
303 .cia_encrypt = aes_encrypt,
304 .cia_decrypt = aes_decrypt
305 }
306 }
307};
308
309static int __init aes_init(void)
310{
311 gen_tabs();
312 return crypto_register_alg(&aes_alg);
313}
314
315static void __exit aes_fini(void)
316{
317 crypto_unregister_alg(&aes_alg);
318}
319
320module_init(aes_init);
321module_exit(aes_fini);
322
323MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
324MODULE_LICENSE("GPL");
Olaf Hering03c6b742005-08-08 14:49:18 -0700325MODULE_ALIAS("aes");