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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 <linux/init.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/mm.h> | |
20 | #include <asm/byteorder.h> | |
21 | #include <linux/crypto.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"); |