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
34struct tea_ctx {
35	u32 KEY[4];
36};
37
38struct xtea_ctx {
39	u32 KEY[4];
40};
41
42static 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
57static 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
85static 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
115static 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
130static 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
151static 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
174static 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
195static 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
217static 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
261static int __init tea_mod_init(void)
262{
263	return crypto_register_algs(tea_algs, ARRAY_SIZE(tea_algs));
264}
265
266static void __exit tea_mod_fini(void)
267{
268	crypto_unregister_algs(tea_algs, ARRAY_SIZE(tea_algs));
269}
270
271MODULE_ALIAS_CRYPTO("tea");
272MODULE_ALIAS_CRYPTO("xtea");
273MODULE_ALIAS_CRYPTO("xeta");
274
275subsys_initcall(tea_mod_init);
276module_exit(tea_mod_fini);
277
278MODULE_LICENSE("GPL");
279MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");
280