1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Cryptographic API.
4 *
5 * TEA, XTEA, and XETA crypto alogrithms
6 *
7 * The TEA and Xtended TEA algorithms were developed by David Wheeler
8 * and Roger Needham at the Computer Laboratory of Cambridge University.
9 *
10 * Due to the order of evaluation in XTEA many people have incorrectly
11 * implemented it. XETA (XTEA in the wrong order), exists for
12 * compatibility with these implementations.
13 *
14 * Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com
15 */
16
17 #include <crypto/algapi.h>
18 #include <linux/init.h>
19 #include <linux/module.h>
20 #include <linux/mm.h>
21 #include <asm/byteorder.h>
22 #include <linux/types.h>
23
24 #define TEA_KEY_SIZE 16
25 #define TEA_BLOCK_SIZE 8
26 #define TEA_ROUNDS 32
27 #define TEA_DELTA 0x9e3779b9
28
29 #define XTEA_KEY_SIZE 16
30 #define XTEA_BLOCK_SIZE 8
31 #define XTEA_ROUNDS 32
32 #define XTEA_DELTA 0x9e3779b9
33
34 struct tea_ctx {
35 u32 KEY[4];
36 };
37
38 struct xtea_ctx {
39 u32 KEY[4];
40 };
41
42 static int tea_setkey(struct crypto_tfm *tfm, const u8 *in_key,
43 unsigned int key_len)
44 {
45 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
46 const __le32 *key = (const __le32 *)in_key;
47
48 ctx->KEY[0] = le32_to_cpu(key[0]);
49 ctx->KEY[1] = le32_to_cpu(key[1]);
50 ctx->KEY[2] = le32_to_cpu(key[2]);
51 ctx->KEY[3] = le32_to_cpu(key[3]);
52
53 return 0;
54
55 }
56
57 static void tea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
58 {
59 u32 y, z, n, sum = 0;
60 u32 k0, k1, k2, k3;
61 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
62 const __le32 *in = (const __le32 *)src;
63 __le32 *out = (__le32 *)dst;
64
65 y = le32_to_cpu(in[0]);
66 z = le32_to_cpu(in[1]);
67
68 k0 = ctx->KEY[0];
69 k1 = ctx->KEY[1];
70 k2 = ctx->KEY[2];
71 k3 = ctx->KEY[3];
72
73 n = TEA_ROUNDS;
74
75 while (n-- > 0) {
76 sum += TEA_DELTA;
77 y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
78 z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
79 }
80
81 out[0] = cpu_to_le32(y);
82 out[1] = cpu_to_le32(z);
83 }
84
85 static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
86 {
87 u32 y, z, n, sum;
88 u32 k0, k1, k2, k3;
89 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
90 const __le32 *in = (const __le32 *)src;
91 __le32 *out = (__le32 *)dst;
92
93 y = le32_to_cpu(in[0]);
94 z = le32_to_cpu(in[1]);
95
96 k0 = ctx->KEY[0];
97 k1 = ctx->KEY[1];
98 k2 = ctx->KEY[2];
99 k3 = ctx->KEY[3];
100
101 sum = TEA_DELTA << 5;
102
103 n = TEA_ROUNDS;
104
105 while (n-- > 0) {
106 z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
107 y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
108 sum -= TEA_DELTA;
109 }
110
111 out[0] = cpu_to_le32(y);
112 out[1] = cpu_to_le32(z);
113 }
114
115 static int xtea_setkey(struct crypto_tfm *tfm, const u8 *in_key,
116 unsigned int key_len)
117 {
118 struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
119 const __le32 *key = (const __le32 *)in_key;
120
121 ctx->KEY[0] = le32_to_cpu(key[0]);
122 ctx->KEY[1] = le32_to_cpu(key[1]);
123 ctx->KEY[2] = le32_to_cpu(key[2]);
124 ctx->KEY[3] = le32_to_cpu(key[3]);
125
126 return 0;
127
128 }
129
130 static void xtea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
131 {
132 u32 y, z, sum = 0;
133 u32 limit = XTEA_DELTA * XTEA_ROUNDS;
134 struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
135 const __le32 *in = (const __le32 *)src;
136 __le32 *out = (__le32 *)dst;
137
138 y = le32_to_cpu(in[0]);
139 z = le32_to_cpu(in[1]);
140
141 while (sum != limit) {
142 y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]);
143 sum += XTEA_DELTA;
144 z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]);
145 }
146
147 out[0] = cpu_to_le32(y);
148 out[1] = cpu_to_le32(z);
149 }
150
151 static void xtea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
152 {
153 u32 y, z, sum;
154 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
155 const __le32 *in = (const __le32 *)src;
156 __le32 *out = (__le32 *)dst;
157
158 y = le32_to_cpu(in[0]);
159 z = le32_to_cpu(in[1]);
160
161 sum = XTEA_DELTA * XTEA_ROUNDS;
162
163 while (sum) {
164 z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]);
165 sum -= XTEA_DELTA;
166 y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]);
167 }
168
169 out[0] = cpu_to_le32(y);
170 out[1] = cpu_to_le32(z);
171 }
172
173
174 static void xeta_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
175 {
176 u32 y, z, sum = 0;
177 u32 limit = XTEA_DELTA * XTEA_ROUNDS;
178 struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
179 const __le32 *in = (const __le32 *)src;
180 __le32 *out = (__le32 *)dst;
181
182 y = le32_to_cpu(in[0]);
183 z = le32_to_cpu(in[1]);
184
185 while (sum != limit) {
186 y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3];
187 sum += XTEA_DELTA;
188 z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3];
189 }
190
191 out[0] = cpu_to_le32(y);
192 out[1] = cpu_to_le32(z);
193 }
194
195 static void xeta_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
196 {
197 u32 y, z, sum;
198 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
199 const __le32 *in = (const __le32 *)src;
200 __le32 *out = (__le32 *)dst;
201
202 y = le32_to_cpu(in[0]);
203 z = le32_to_cpu(in[1]);
204
205 sum = XTEA_DELTA * XTEA_ROUNDS;
206
207 while (sum) {
208 z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3];
209 sum -= XTEA_DELTA;
210 y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3];
211 }
212
213 out[0] = cpu_to_le32(y);
214 out[1] = cpu_to_le32(z);
215 }
216
217 static struct crypto_alg tea_algs[3] = { {
218 .cra_name = "tea",
219 .cra_driver_name = "tea-generic",
220 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
221 .cra_blocksize = TEA_BLOCK_SIZE,
222 .cra_ctxsize = sizeof (struct tea_ctx),
223 .cra_alignmask = 3,
224 .cra_module = THIS_MODULE,
225 .cra_u = { .cipher = {
226 .cia_min_keysize = TEA_KEY_SIZE,
227 .cia_max_keysize = TEA_KEY_SIZE,
228 .cia_setkey = tea_setkey,
229 .cia_encrypt = tea_encrypt,
230 .cia_decrypt = tea_decrypt } }
231 }, {
232 .cra_name = "xtea",
233 .cra_driver_name = "xtea-generic",
234 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
235 .cra_blocksize = XTEA_BLOCK_SIZE,
236 .cra_ctxsize = sizeof (struct xtea_ctx),
237 .cra_alignmask = 3,
238 .cra_module = THIS_MODULE,
239 .cra_u = { .cipher = {
240 .cia_min_keysize = XTEA_KEY_SIZE,
241 .cia_max_keysize = XTEA_KEY_SIZE,
242 .cia_setkey = xtea_setkey,
243 .cia_encrypt = xtea_encrypt,
244 .cia_decrypt = xtea_decrypt } }
245 }, {
246 .cra_name = "xeta",
247 .cra_driver_name = "xeta-generic",
248 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
249 .cra_blocksize = XTEA_BLOCK_SIZE,
250 .cra_ctxsize = sizeof (struct xtea_ctx),
251 .cra_alignmask = 3,
252 .cra_module = THIS_MODULE,
253 .cra_u = { .cipher = {
254 .cia_min_keysize = XTEA_KEY_SIZE,
255 .cia_max_keysize = XTEA_KEY_SIZE,
256 .cia_setkey = xtea_setkey,
257 .cia_encrypt = xeta_encrypt,
258 .cia_decrypt = xeta_decrypt } }
259 } };
260
261 static int __init tea_mod_init(void)
262 {
263 return crypto_register_algs(tea_algs, ARRAY_SIZE(tea_algs));
264 }
265
266 static void __exit tea_mod_fini(void)
267 {
268 crypto_unregister_algs(tea_algs, ARRAY_SIZE(tea_algs));
269 }
270
271 MODULE_ALIAS_CRYPTO("tea");
272 MODULE_ALIAS_CRYPTO("xtea");
273 MODULE_ALIAS_CRYPTO("xeta");
274
275 subsys_initcall(tea_mod_init);
276 module_exit(tea_mod_fini);
277
278 MODULE_LICENSE("GPL");
279 MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");
280
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