1 /*
2 * Cryptographic API.
3 *
4 * TEA, XTEA, and XETA crypto alogrithms
5 *
6 * The TEA and Xtended TEA algorithms were developed by David Wheeler
7 * and Roger Needham at the Computer Laboratory of Cambridge University.
8 *
9 * Due to the order of evaluation in XTEA many people have incorrectly
10 * implemented it. XETA (XTEA in the wrong order), exists for
11 * compatibility with these implementations.
12 *
13 * Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com
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
22 #include <linux/init.h>
23 #include <linux/module.h>
24 #include <linux/mm.h>
25 #include <asm/scatterlist.h>
26 #include <linux/crypto.h>
27
28 #define TEA_KEY_SIZE 16
29 #define TEA_BLOCK_SIZE 8
30 #define TEA_ROUNDS 32
31 #define TEA_DELTA 0x9e3779b9
32
33 #define XTEA_KEY_SIZE 16
34 #define XTEA_BLOCK_SIZE 8
35 #define XTEA_ROUNDS 32
36 #define XTEA_DELTA 0x9e3779b9
37
38 #define u32_in(x) le32_to_cpu(*(const u32 *)(x))
39 #define u32_out(to, from) (*(u32 *)(to) = cpu_to_le32(from))
40
41 struct tea_ctx {
42 u32 KEY[4];
43 };
44
45 struct xtea_ctx {
46 u32 KEY[4];
47 };
48
tea_setkey(void * ctx_arg,const u8 * in_key,unsigned int key_len,u32 * flags)49 static int tea_setkey(void *ctx_arg, const u8 *in_key,
50 unsigned int key_len, u32 *flags)
51 {
52
53 struct tea_ctx *ctx = ctx_arg;
54
55 if (key_len != 16)
56 {
57 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
58 return -EINVAL;
59 }
60
61 ctx->KEY[0] = u32_in (in_key);
62 ctx->KEY[1] = u32_in (in_key + 4);
63 ctx->KEY[2] = u32_in (in_key + 8);
64 ctx->KEY[3] = u32_in (in_key + 12);
65
66 return 0;
67
68 }
69
tea_encrypt(void * ctx_arg,u8 * dst,const u8 * src)70 static void tea_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
71 {
72 u32 y, z, n, sum = 0;
73 u32 k0, k1, k2, k3;
74
75 struct tea_ctx *ctx = ctx_arg;
76
77 y = u32_in (src);
78 z = u32_in (src + 4);
79
80 k0 = ctx->KEY[0];
81 k1 = ctx->KEY[1];
82 k2 = ctx->KEY[2];
83 k3 = ctx->KEY[3];
84
85 n = TEA_ROUNDS;
86
87 while (n-- > 0) {
88 sum += TEA_DELTA;
89 y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
90 z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
91 }
92
93 u32_out (dst, y);
94 u32_out (dst + 4, z);
95 }
96
tea_decrypt(void * ctx_arg,u8 * dst,const u8 * src)97 static void tea_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
98 {
99 u32 y, z, n, sum;
100 u32 k0, k1, k2, k3;
101
102 struct tea_ctx *ctx = ctx_arg;
103
104 y = u32_in (src);
105 z = u32_in (src + 4);
106
107 k0 = ctx->KEY[0];
108 k1 = ctx->KEY[1];
109 k2 = ctx->KEY[2];
110 k3 = ctx->KEY[3];
111
112 sum = TEA_DELTA << 5;
113
114 n = TEA_ROUNDS;
115
116 while (n-- > 0) {
117 z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
118 y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
119 sum -= TEA_DELTA;
120 }
121
122 u32_out (dst, y);
123 u32_out (dst + 4, z);
124
125 }
126
xtea_setkey(void * ctx_arg,const u8 * in_key,unsigned int key_len,u32 * flags)127 static int xtea_setkey(void *ctx_arg, const u8 *in_key,
128 unsigned int key_len, u32 *flags)
129 {
130
131 struct xtea_ctx *ctx = ctx_arg;
132
133 if (key_len != 16)
134 {
135 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
136 return -EINVAL;
137 }
138
139 ctx->KEY[0] = u32_in (in_key);
140 ctx->KEY[1] = u32_in (in_key + 4);
141 ctx->KEY[2] = u32_in (in_key + 8);
142 ctx->KEY[3] = u32_in (in_key + 12);
143
144 return 0;
145
146 }
147
xtea_encrypt(void * ctx_arg,u8 * dst,const u8 * src)148 static void xtea_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
149 {
150
151 u32 y, z, sum = 0;
152 u32 limit = XTEA_DELTA * XTEA_ROUNDS;
153
154 struct xtea_ctx *ctx = ctx_arg;
155
156 y = u32_in (src);
157 z = u32_in (src + 4);
158
159 while (sum != limit) {
160 y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]);
161 sum += XTEA_DELTA;
162 z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]);
163 }
164
165 u32_out (dst, y);
166 u32_out (dst + 4, z);
167
168 }
169
xtea_decrypt(void * ctx_arg,u8 * dst,const u8 * src)170 static void xtea_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
171 {
172
173 u32 y, z, sum;
174 struct tea_ctx *ctx = ctx_arg;
175
176 y = u32_in (src);
177 z = u32_in (src + 4);
178
179 sum = XTEA_DELTA * XTEA_ROUNDS;
180
181 while (sum) {
182 z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]);
183 sum -= XTEA_DELTA;
184 y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]);
185 }
186
187 u32_out (dst, y);
188 u32_out (dst + 4, z);
189
190 }
191
xeta_encrypt(void * ctx_arg,u8 * dst,const u8 * src)192 static void xeta_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
193 {
194
195 u32 y, z, sum = 0;
196 u32 limit = XTEA_DELTA * XTEA_ROUNDS;
197
198 struct xtea_ctx *ctx = ctx_arg;
199
200 y = u32_in (src);
201 z = u32_in (src + 4);
202
203 while (sum != limit) {
204 y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3];
205 sum += XTEA_DELTA;
206 z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3];
207
208 }
209
210 u32_out (dst, y);
211 u32_out (dst + 4, z);
212
213 }
214
xeta_decrypt(void * ctx_arg,u8 * dst,const u8 * src)215 static void xeta_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
216 {
217
218 u32 y, z, sum;
219 struct tea_ctx *ctx = ctx_arg;
220
221 y = u32_in (src);
222 z = u32_in (src + 4);
223
224 sum = XTEA_DELTA * XTEA_ROUNDS;
225
226 while (sum) {
227 z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3];
228 sum -= XTEA_DELTA;
229 y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3];
230 }
231
232 u32_out (dst, y);
233 u32_out (dst + 4, z);
234
235 }
236
237 static struct crypto_alg tea_alg = {
238 .cra_name = "tea",
239 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
240 .cra_blocksize = TEA_BLOCK_SIZE,
241 .cra_ctxsize = sizeof (struct tea_ctx),
242 .cra_module = THIS_MODULE,
243 .cra_list = LIST_HEAD_INIT(tea_alg.cra_list),
244 .cra_u = { .cipher = {
245 .cia_min_keysize = TEA_KEY_SIZE,
246 .cia_max_keysize = TEA_KEY_SIZE,
247 .cia_setkey = tea_setkey,
248 .cia_encrypt = tea_encrypt,
249 .cia_decrypt = tea_decrypt } }
250 };
251
252 static struct crypto_alg xtea_alg = {
253 .cra_name = "xtea",
254 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
255 .cra_blocksize = XTEA_BLOCK_SIZE,
256 .cra_ctxsize = sizeof (struct xtea_ctx),
257 .cra_module = THIS_MODULE,
258 .cra_list = LIST_HEAD_INIT(xtea_alg.cra_list),
259 .cra_u = { .cipher = {
260 .cia_min_keysize = XTEA_KEY_SIZE,
261 .cia_max_keysize = XTEA_KEY_SIZE,
262 .cia_setkey = xtea_setkey,
263 .cia_encrypt = xtea_encrypt,
264 .cia_decrypt = xtea_decrypt } }
265 };
266
267
268 static struct crypto_alg xeta_alg = {
269 .cra_name = "xeta",
270 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
271 .cra_blocksize = XTEA_BLOCK_SIZE,
272 .cra_ctxsize = sizeof (struct xtea_ctx),
273 .cra_module = THIS_MODULE,
274 .cra_list = LIST_HEAD_INIT(xtea_alg.cra_list),
275 .cra_u = { .cipher = {
276 .cia_min_keysize = XTEA_KEY_SIZE,
277 .cia_max_keysize = XTEA_KEY_SIZE,
278 .cia_setkey = xtea_setkey,
279 .cia_encrypt = xeta_encrypt,
280 .cia_decrypt = xeta_decrypt } }
281 };
282
init(void)283 static int __init init(void)
284 {
285 int ret = 0;
286
287 ret = crypto_register_alg(&tea_alg);
288 if (ret < 0)
289 goto out;
290
291 ret = crypto_register_alg(&xtea_alg);
292 if (ret < 0) {
293 crypto_unregister_alg(&tea_alg);
294 goto out;
295 }
296
297 ret = crypto_register_alg(&xeta_alg);
298 if (ret < 0) {
299 crypto_unregister_alg(&tea_alg);
300 crypto_unregister_alg(&xtea_alg);
301 goto out;
302 }
303
304 out:
305 return ret;
306 }
307
fini(void)308 static void __exit fini(void)
309 {
310 crypto_unregister_alg(&tea_alg);
311 crypto_unregister_alg(&xtea_alg);
312 crypto_unregister_alg(&xeta_alg);
313 }
314
315 module_init(init);
316 module_exit(fini);
317
318 MODULE_LICENSE("GPL");
319 MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");
320