?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
[CRYPTO] aes: Add wrappers for assembly routines
[linux-2.6.git] / arch / x86_64 / crypto / aes.c
blob68866fab37aa15804a76065286e87cb55da85804
1 /*
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 */
72 static inline u8 byte(const u32 x, const unsigned n)
73 {
74 return x >> (n << 3);
75 }
76
77 struct aes_ctx
78 {
79 u32 key_length;
80 u32 buf[120];
81 };
82
83 #define E_KEY (&ctx->buf[0])
84 #define D_KEY (&ctx->buf[60])
85
86 static u8 pow_tab[256] __initdata;
87 static u8 log_tab[256] __initdata;
88 static u8 sbx_tab[256] __initdata;
89 static u8 isb_tab[256] __initdata;
90 static u32 rco_tab[10];
91 u32 aes_ft_tab[4][256];
92 u32 aes_it_tab[4][256];
93
94 u32 aes_fl_tab[4][256];
95 u32 aes_il_tab[4][256];
96
97 static inline u8 f_mult(u8 a, u8 b)
98 {
99 u8 aa = log_tab[a], cc = aa + log_tab[b];
100
101 return pow_tab[cc + (cc < aa ? 1 : 0)];
102 }
103
104 #define ff_mult(a, b) (a && b ? f_mult(a, b) : 0)
105
106 #define ls_box(x) \
107 (aes_fl_tab[0][byte(x, 0)] ^ \
108 aes_fl_tab[1][byte(x, 1)] ^ \
109 aes_fl_tab[2][byte(x, 2)] ^ \
110 aes_fl_tab[3][byte(x, 3)])
111
112 static void __init gen_tabs(void)
113 {
114 u32 i, t;
115 u8 p, q;
116
117 /* log and power tables for GF(2**8) finite field with
118 0x011b as modular polynomial - the simplest primitive
119 root is 0x03, used here to generate the tables */
120
121 for (i = 0, p = 1; i < 256; ++i) {
122 pow_tab[i] = (u8)p;
123 log_tab[p] = (u8)i;
124
125 p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
126 }
127
128 log_tab[1] = 0;
129
130 for (i = 0, p = 1; i < 10; ++i) {
131 rco_tab[i] = p;
132
133 p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
134 }
135
136 for (i = 0; i < 256; ++i) {
137 p = (i ? pow_tab[255 - log_tab[i]] : 0);
138 q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
139 p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
140 sbx_tab[i] = p;
141 isb_tab[p] = (u8)i;
142 }
143
144 for (i = 0; i < 256; ++i) {
145 p = sbx_tab[i];
146
147 t = p;
148 aes_fl_tab[0][i] = t;
149 aes_fl_tab[1][i] = rol32(t, 8);
150 aes_fl_tab[2][i] = rol32(t, 16);
151 aes_fl_tab[3][i] = rol32(t, 24);
152
153 t = ((u32)ff_mult(2, p)) |
154 ((u32)p << 8) |
155 ((u32)p << 16) | ((u32)ff_mult(3, p) << 24);
156
157 aes_ft_tab[0][i] = t;
158 aes_ft_tab[1][i] = rol32(t, 8);
159 aes_ft_tab[2][i] = rol32(t, 16);
160 aes_ft_tab[3][i] = rol32(t, 24);
161
162 p = isb_tab[i];
163
164 t = p;
165 aes_il_tab[0][i] = t;
166 aes_il_tab[1][i] = rol32(t, 8);
167 aes_il_tab[2][i] = rol32(t, 16);
168 aes_il_tab[3][i] = rol32(t, 24);
169
170 t = ((u32)ff_mult(14, p)) |
171 ((u32)ff_mult(9, p) << 8) |
172 ((u32)ff_mult(13, p) << 16) |
173 ((u32)ff_mult(11, p) << 24);
174
175 aes_it_tab[0][i] = t;
176 aes_it_tab[1][i] = rol32(t, 8);
177 aes_it_tab[2][i] = rol32(t, 16);
178 aes_it_tab[3][i] = rol32(t, 24);
179 }
180 }
181
182 #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
183
184 #define imix_col(y, x) \
185 u = star_x(x); \
186 v = star_x(u); \
187 w = star_x(v); \
188 t = w ^ (x); \
189 (y) = u ^ v ^ w; \
190 (y) ^= ror32(u ^ t, 8) ^ \
191 ror32(v ^ t, 16) ^ \
192 ror32(t, 24)
193
194 /* initialise the key schedule from the user supplied key */
195
196 #define loop4(i) \
197 { \
198 t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \
199 t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \
200 t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \
201 t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \
202 t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \
203 }
204
205 #define loop6(i) \
206 { \
207 t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \
208 t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \
209 t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \
210 t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \
211 t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \
212 t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \
213 t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \
214 }
215
216 #define loop8(i) \
217 { \
218 t = ror32(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \
219 t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \
220 t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \
221 t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \
222 t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \
223 t = E_KEY[8 * i + 4] ^ ls_box(t); \
224 E_KEY[8 * i + 12] = t; \
225 t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \
226 t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \
227 t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \
228 }
229
230 static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
231 unsigned int key_len, u32 *flags)
232 {
233 struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
234 const __le32 *key = (const __le32 *)in_key;
235 u32 i, j, t, u, v, w;
236
237 if (key_len != 16 && key_len != 24 && key_len != 32) {
238 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
239 return -EINVAL;
240 }
241
242 ctx->key_length = key_len;
243
244 D_KEY[key_len + 24] = E_KEY[0] = le32_to_cpu(key[0]);
245 D_KEY[key_len + 25] = E_KEY[1] = le32_to_cpu(key[1]);
246 D_KEY[key_len + 26] = E_KEY[2] = le32_to_cpu(key[2]);
247 D_KEY[key_len + 27] = E_KEY[3] = le32_to_cpu(key[3]);
248
249 switch (key_len) {
250 case 16:
251 t = E_KEY[3];
252 for (i = 0; i < 10; ++i)
253 loop4(i);
254 break;
255
256 case 24:
257 E_KEY[4] = le32_to_cpu(key[4]);
258 t = E_KEY[5] = le32_to_cpu(key[5]);
259 for (i = 0; i < 8; ++i)
260 loop6 (i);
261 break;
262
263 case 32:
264 E_KEY[4] = le32_to_cpu(key[4]);
265 E_KEY[5] = le32_to_cpu(key[5]);
266 E_KEY[6] = le32_to_cpu(key[6]);
267 t = E_KEY[7] = le32_to_cpu(key[7]);
268 for (i = 0; i < 7; ++i)
269 loop8(i);
270 break;
271 }
272
273 D_KEY[0] = E_KEY[key_len + 24];
274 D_KEY[1] = E_KEY[key_len + 25];
275 D_KEY[2] = E_KEY[key_len + 26];
276 D_KEY[3] = E_KEY[key_len + 27];
277
278 for (i = 4; i < key_len + 24; ++i) {
279 j = key_len + 24 - (i & ~3) + (i & 3);
280 imix_col(D_KEY[j], E_KEY[i]);
281 }
282
283 return 0;
284 }
285
286 asmlinkage void aes_enc_blk(struct crypto_tfm *tfm, u8 *out, const u8 *in);
287 asmlinkage void aes_dec_blk(struct crypto_tfm *tfm, u8 *out, const u8 *in);
288
289 static void aes_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
290 {
291 aes_enc_blk(tfm, dst, src);
292 }
293
294 static void aes_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
295 {
296 aes_dec_blk(tfm, dst, src);
297 }
298
299 static struct crypto_alg aes_alg = {
300 .cra_name = "aes",
301 .cra_driver_name = "aes-x86_64",
302 .cra_priority = 200,
303 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
304 .cra_blocksize = AES_BLOCK_SIZE,
305 .cra_ctxsize = sizeof(struct aes_ctx),
306 .cra_module = THIS_MODULE,
307 .cra_list = LIST_HEAD_INIT(aes_alg.cra_list),
308 .cra_u = {
309 .cipher = {
310 .cia_min_keysize = AES_MIN_KEY_SIZE,
311 .cia_max_keysize = AES_MAX_KEY_SIZE,
312 .cia_setkey = aes_set_key,
313 .cia_encrypt = aes_encrypt,
314 .cia_decrypt = aes_decrypt
315 }
316 }
317 };
318
319 static int __init aes_init(void)
320 {
321 gen_tabs();
322 return crypto_register_alg(&aes_alg);
323 }
324
325 static void __exit aes_fini(void)
326 {
327 crypto_unregister_alg(&aes_alg);
328 }
329
330 module_init(aes_init);
331 module_exit(aes_fini);
332
333 MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
334 MODULE_LICENSE("GPL");
335 MODULE_ALIAS("aes");
Linus' kernel tree