1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Kernel cryptographic api.
3 * cast6.c - Cast6 cipher algorithm [rfc2612].
4 *
5 * CAST-256 (*cast6*) is a DES like Substitution-Permutation Network (SPN)
6 * cryptosystem built upon the CAST-128 (*cast5*) [rfc2144] encryption
7 * algorithm.
8 *
9 * Copyright (C) 2003 Kartikey Mahendra Bhatt <kartik_me@hotmail.com>.
10 */
11
12
13 #include <asm/unaligned.h>
14 #include <crypto/algapi.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/errno.h>
18 #include <linux/string.h>
19 #include <linux/types.h>
20 #include <crypto/cast6.h>
21
22 #define s1 cast_s1
23 #define s2 cast_s2
24 #define s3 cast_s3
25 #define s4 cast_s4
26
27 #define F1(D, r, m) ((I = ((m) + (D))), (I = rol32(I, (r))), \
28 (((s1[I >> 24] ^ s2[(I>>16)&0xff]) - s3[(I>>8)&0xff]) + s4[I&0xff]))
29 #define F2(D, r, m) ((I = ((m) ^ (D))), (I = rol32(I, (r))), \
30 (((s1[I >> 24] - s2[(I>>16)&0xff]) + s3[(I>>8)&0xff]) ^ s4[I&0xff]))
31 #define F3(D, r, m) ((I = ((m) - (D))), (I = rol32(I, (r))), \
32 (((s1[I >> 24] + s2[(I>>16)&0xff]) ^ s3[(I>>8)&0xff]) - s4[I&0xff]))
33
34 static const u32 Tm[24][8] = {
35 { 0x5a827999, 0xc95c653a, 0x383650db, 0xa7103c7c, 0x15ea281d,
36 0x84c413be, 0xf39dff5f, 0x6277eb00 } ,
37 { 0xd151d6a1, 0x402bc242, 0xaf05ade3, 0x1ddf9984, 0x8cb98525,
38 0xfb9370c6, 0x6a6d5c67, 0xd9474808 } ,
39 { 0x482133a9, 0xb6fb1f4a, 0x25d50aeb, 0x94aef68c, 0x0388e22d,
40 0x7262cdce, 0xe13cb96f, 0x5016a510 } ,
41 { 0xbef090b1, 0x2dca7c52, 0x9ca467f3, 0x0b7e5394, 0x7a583f35,
42 0xe9322ad6, 0x580c1677, 0xc6e60218 } ,
43 { 0x35bfedb9, 0xa499d95a, 0x1373c4fb, 0x824db09c, 0xf1279c3d,
44 0x600187de, 0xcedb737f, 0x3db55f20 } ,
45 { 0xac8f4ac1, 0x1b693662, 0x8a432203, 0xf91d0da4, 0x67f6f945,
46 0xd6d0e4e6, 0x45aad087, 0xb484bc28 } ,
47 { 0x235ea7c9, 0x9238936a, 0x01127f0b, 0x6fec6aac, 0xdec6564d,
48 0x4da041ee, 0xbc7a2d8f, 0x2b541930 } ,
49 { 0x9a2e04d1, 0x0907f072, 0x77e1dc13, 0xe6bbc7b4, 0x5595b355,
50 0xc46f9ef6, 0x33498a97, 0xa2237638 } ,
51 { 0x10fd61d9, 0x7fd74d7a, 0xeeb1391b, 0x5d8b24bc, 0xcc65105d,
52 0x3b3efbfe, 0xaa18e79f, 0x18f2d340 } ,
53 { 0x87ccbee1, 0xf6a6aa82, 0x65809623, 0xd45a81c4, 0x43346d65,
54 0xb20e5906, 0x20e844a7, 0x8fc23048 } ,
55 { 0xfe9c1be9, 0x6d76078a, 0xdc4ff32b, 0x4b29decc, 0xba03ca6d,
56 0x28ddb60e, 0x97b7a1af, 0x06918d50 } ,
57 { 0x756b78f1, 0xe4456492, 0x531f5033, 0xc1f93bd4, 0x30d32775,
58 0x9fad1316, 0x0e86feb7, 0x7d60ea58 } ,
59 { 0xec3ad5f9, 0x5b14c19a, 0xc9eead3b, 0x38c898dc, 0xa7a2847d,
60 0x167c701e, 0x85565bbf, 0xf4304760 } ,
61 { 0x630a3301, 0xd1e41ea2, 0x40be0a43, 0xaf97f5e4, 0x1e71e185,
62 0x8d4bcd26, 0xfc25b8c7, 0x6affa468 } ,
63 { 0xd9d99009, 0x48b37baa, 0xb78d674b, 0x266752ec, 0x95413e8d,
64 0x041b2a2e, 0x72f515cf, 0xe1cf0170 } ,
65 { 0x50a8ed11, 0xbf82d8b2, 0x2e5cc453, 0x9d36aff4, 0x0c109b95,
66 0x7aea8736, 0xe9c472d7, 0x589e5e78 } ,
67 { 0xc7784a19, 0x365235ba, 0xa52c215b, 0x14060cfc, 0x82dff89d,
68 0xf1b9e43e, 0x6093cfdf, 0xcf6dbb80 } ,
69 { 0x3e47a721, 0xad2192c2, 0x1bfb7e63, 0x8ad56a04, 0xf9af55a5,
70 0x68894146, 0xd7632ce7, 0x463d1888 } ,
71 { 0xb5170429, 0x23f0efca, 0x92cadb6b, 0x01a4c70c, 0x707eb2ad,
72 0xdf589e4e, 0x4e3289ef, 0xbd0c7590 } ,
73 { 0x2be66131, 0x9ac04cd2, 0x099a3873, 0x78742414, 0xe74e0fb5,
74 0x5627fb56, 0xc501e6f7, 0x33dbd298 } ,
75 { 0xa2b5be39, 0x118fa9da, 0x8069957b, 0xef43811c, 0x5e1d6cbd,
76 0xccf7585e, 0x3bd143ff, 0xaaab2fa0 } ,
77 { 0x19851b41, 0x885f06e2, 0xf738f283, 0x6612de24, 0xd4ecc9c5,
78 0x43c6b566, 0xb2a0a107, 0x217a8ca8 } ,
79 { 0x90547849, 0xff2e63ea, 0x6e084f8b, 0xdce23b2c, 0x4bbc26cd,
80 0xba96126e, 0x296ffe0f, 0x9849e9b0 } ,
81 { 0x0723d551, 0x75fdc0f2, 0xe4d7ac93, 0x53b19834, 0xc28b83d5,
82 0x31656f76, 0xa03f5b17, 0x0f1946b8 }
83 };
84
85 static const u8 Tr[4][8] = {
86 { 0x13, 0x04, 0x15, 0x06, 0x17, 0x08, 0x19, 0x0a } ,
87 { 0x1b, 0x0c, 0x1d, 0x0e, 0x1f, 0x10, 0x01, 0x12 } ,
88 { 0x03, 0x14, 0x05, 0x16, 0x07, 0x18, 0x09, 0x1a } ,
89 { 0x0b, 0x1c, 0x0d, 0x1e, 0x0f, 0x00, 0x11, 0x02 }
90 };
91
92 /* forward octave */
93 static inline void W(u32 *key, unsigned int i)
94 {
95 u32 I;
96 key[6] ^= F1(key[7], Tr[i % 4][0], Tm[i][0]);
97 key[5] ^= F2(key[6], Tr[i % 4][1], Tm[i][1]);
98 key[4] ^= F3(key[5], Tr[i % 4][2], Tm[i][2]);
99 key[3] ^= F1(key[4], Tr[i % 4][3], Tm[i][3]);
100 key[2] ^= F2(key[3], Tr[i % 4][4], Tm[i][4]);
101 key[1] ^= F3(key[2], Tr[i % 4][5], Tm[i][5]);
102 key[0] ^= F1(key[1], Tr[i % 4][6], Tm[i][6]);
103 key[7] ^= F2(key[0], Tr[i % 4][7], Tm[i][7]);
104 }
105
106 int __cast6_setkey(struct cast6_ctx *c, const u8 *in_key, unsigned int key_len)
107 {
108 int i;
109 u32 key[8];
110 __be32 p_key[8]; /* padded key */
111
112 if (key_len % 4 != 0)
113 return -EINVAL;
114
115 memset(p_key, 0, 32);
116 memcpy(p_key, in_key, key_len);
117
118 key[0] = be32_to_cpu(p_key[0]); /* A */
119 key[1] = be32_to_cpu(p_key[1]); /* B */
120 key[2] = be32_to_cpu(p_key[2]); /* C */
121 key[3] = be32_to_cpu(p_key[3]); /* D */
122 key[4] = be32_to_cpu(p_key[4]); /* E */
123 key[5] = be32_to_cpu(p_key[5]); /* F */
124 key[6] = be32_to_cpu(p_key[6]); /* G */
125 key[7] = be32_to_cpu(p_key[7]); /* H */
126
127 for (i = 0; i < 12; i++) {
128 W(key, 2 * i);
129 W(key, 2 * i + 1);
130
131 c->Kr[i][0] = key[0] & 0x1f;
132 c->Kr[i][1] = key[2] & 0x1f;
133 c->Kr[i][2] = key[4] & 0x1f;
134 c->Kr[i][3] = key[6] & 0x1f;
135
136 c->Km[i][0] = key[7];
137 c->Km[i][1] = key[5];
138 c->Km[i][2] = key[3];
139 c->Km[i][3] = key[1];
140 }
141
142 return 0;
143 }
144 EXPORT_SYMBOL_GPL(__cast6_setkey);
145
146 int cast6_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
147 {
148 return __cast6_setkey(crypto_tfm_ctx(tfm), key, keylen);
149 }
150 EXPORT_SYMBOL_GPL(cast6_setkey);
151
152 /*forward quad round*/
153 static inline void Q(u32 *block, const u8 *Kr, const u32 *Km)
154 {
155 u32 I;
156 block[2] ^= F1(block[3], Kr[0], Km[0]);
157 block[1] ^= F2(block[2], Kr[1], Km[1]);
158 block[0] ^= F3(block[1], Kr[2], Km[2]);
159 block[3] ^= F1(block[0], Kr[3], Km[3]);
160 }
161
162 /*reverse quad round*/
163 static inline void QBAR(u32 *block, const u8 *Kr, const u32 *Km)
164 {
165 u32 I;
166 block[3] ^= F1(block[0], Kr[3], Km[3]);
167 block[0] ^= F3(block[1], Kr[2], Km[2]);
168 block[1] ^= F2(block[2], Kr[1], Km[1]);
169 block[2] ^= F1(block[3], Kr[0], Km[0]);
170 }
171
172 void __cast6_encrypt(const void *ctx, u8 *outbuf, const u8 *inbuf)
173 {
174 const struct cast6_ctx *c = ctx;
175 u32 block[4];
176 const u32 *Km;
177 const u8 *Kr;
178
179 block[0] = get_unaligned_be32(inbuf);
180 block[1] = get_unaligned_be32(inbuf + 4);
181 block[2] = get_unaligned_be32(inbuf + 8);
182 block[3] = get_unaligned_be32(inbuf + 12);
183
184 Km = c->Km[0]; Kr = c->Kr[0]; Q(block, Kr, Km);
185 Km = c->Km[1]; Kr = c->Kr[1]; Q(block, Kr, Km);
186 Km = c->Km[2]; Kr = c->Kr[2]; Q(block, Kr, Km);
187 Km = c->Km[3]; Kr = c->Kr[3]; Q(block, Kr, Km);
188 Km = c->Km[4]; Kr = c->Kr[4]; Q(block, Kr, Km);
189 Km = c->Km[5]; Kr = c->Kr[5]; Q(block, Kr, Km);
190 Km = c->Km[6]; Kr = c->Kr[6]; QBAR(block, Kr, Km);
191 Km = c->Km[7]; Kr = c->Kr[7]; QBAR(block, Kr, Km);
192 Km = c->Km[8]; Kr = c->Kr[8]; QBAR(block, Kr, Km);
193 Km = c->Km[9]; Kr = c->Kr[9]; QBAR(block, Kr, Km);
194 Km = c->Km[10]; Kr = c->Kr[10]; QBAR(block, Kr, Km);
195 Km = c->Km[11]; Kr = c->Kr[11]; QBAR(block, Kr, Km);
196
197 put_unaligned_be32(block[0], outbuf);
198 put_unaligned_be32(block[1], outbuf + 4);
199 put_unaligned_be32(block[2], outbuf + 8);
200 put_unaligned_be32(block[3], outbuf + 12);
201 }
202 EXPORT_SYMBOL_GPL(__cast6_encrypt);
203
204 static void cast6_encrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
205 {
206 __cast6_encrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
207 }
208
209 void __cast6_decrypt(const void *ctx, u8 *outbuf, const u8 *inbuf)
210 {
211 const struct cast6_ctx *c = ctx;
212 u32 block[4];
213 const u32 *Km;
214 const u8 *Kr;
215
216 block[0] = get_unaligned_be32(inbuf);
217 block[1] = get_unaligned_be32(inbuf + 4);
218 block[2] = get_unaligned_be32(inbuf + 8);
219 block[3] = get_unaligned_be32(inbuf + 12);
220
221 Km = c->Km[11]; Kr = c->Kr[11]; Q(block, Kr, Km);
222 Km = c->Km[10]; Kr = c->Kr[10]; Q(block, Kr, Km);
223 Km = c->Km[9]; Kr = c->Kr[9]; Q(block, Kr, Km);
224 Km = c->Km[8]; Kr = c->Kr[8]; Q(block, Kr, Km);
225 Km = c->Km[7]; Kr = c->Kr[7]; Q(block, Kr, Km);
226 Km = c->Km[6]; Kr = c->Kr[6]; Q(block, Kr, Km);
227 Km = c->Km[5]; Kr = c->Kr[5]; QBAR(block, Kr, Km);
228 Km = c->Km[4]; Kr = c->Kr[4]; QBAR(block, Kr, Km);
229 Km = c->Km[3]; Kr = c->Kr[3]; QBAR(block, Kr, Km);
230 Km = c->Km[2]; Kr = c->Kr[2]; QBAR(block, Kr, Km);
231 Km = c->Km[1]; Kr = c->Kr[1]; QBAR(block, Kr, Km);
232 Km = c->Km[0]; Kr = c->Kr[0]; QBAR(block, Kr, Km);
233
234 put_unaligned_be32(block[0], outbuf);
235 put_unaligned_be32(block[1], outbuf + 4);
236 put_unaligned_be32(block[2], outbuf + 8);
237 put_unaligned_be32(block[3], outbuf + 12);
238 }
239 EXPORT_SYMBOL_GPL(__cast6_decrypt);
240
241 static void cast6_decrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
242 {
243 __cast6_decrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
244 }
245
246 static struct crypto_alg alg = {
247 .cra_name = "cast6",
248 .cra_driver_name = "cast6-generic",
249 .cra_priority = 100,
250 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
251 .cra_blocksize = CAST6_BLOCK_SIZE,
252 .cra_ctxsize = sizeof(struct cast6_ctx),
253 .cra_module = THIS_MODULE,
254 .cra_u = {
255 .cipher = {
256 .cia_min_keysize = CAST6_MIN_KEY_SIZE,
257 .cia_max_keysize = CAST6_MAX_KEY_SIZE,
258 .cia_setkey = cast6_setkey,
259 .cia_encrypt = cast6_encrypt,
260 .cia_decrypt = cast6_decrypt}
261 }
262 };
263
264 static int __init cast6_mod_init(void)
265 {
266 return crypto_register_alg(&alg);
267 }
268
269 static void __exit cast6_mod_fini(void)
270 {
271 crypto_unregister_alg(&alg);
272 }
273
274 subsys_initcall(cast6_mod_init);
275 module_exit(cast6_mod_fini);
276
277 MODULE_LICENSE("GPL");
278 MODULE_DESCRIPTION("Cast6 Cipher Algorithm");
279 MODULE_ALIAS_CRYPTO("cast6");
280 MODULE_ALIAS_CRYPTO("cast6-generic");
281
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