1 // SPDX-License-Identifier: GPL-2.0-or-later <<
2 /* 1 /*
3 * Twofish for CryptoAPI 2 * Twofish for CryptoAPI
4 * 3 *
5 * Originally Twofish for GPG 4 * Originally Twofish for GPG
6 * By Matthew Skala <mskala@ansuz.sooke.bc.ca> 5 * By Matthew Skala <mskala@ansuz.sooke.bc.ca>, July 26, 1998
7 * 256-bit key length added March 20, 1999 6 * 256-bit key length added March 20, 1999
8 * Some modifications to reduce the text size 7 * Some modifications to reduce the text size by Werner Koch, April, 1998
9 * Ported to the kerneli patch by Marc Mutz <M 8 * Ported to the kerneli patch by Marc Mutz <Marc@Mutz.com>
10 * Ported to CryptoAPI by Colin Slater <hoho@t 9 * Ported to CryptoAPI by Colin Slater <hoho@tacomeat.net>
11 * 10 *
12 * The original author has disclaimed all copy 11 * The original author has disclaimed all copyright interest in this
13 * code and thus put it in the public domain. 12 * code and thus put it in the public domain. The subsequent authors
14 * have put this under the GNU General Public 13 * have put this under the GNU General Public License.
15 * 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 * This program is distributed in the hope that it will be useful,
>> 21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> 22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> 23 * GNU General Public License for more details.
>> 24 *
>> 25 * You should have received a copy of the GNU General Public License
>> 26 * along with this program; if not, write to the Free Software
>> 27 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
>> 28 * USA
>> 29 *
16 * This code is a "clean room" implementation, 30 * This code is a "clean room" implementation, written from the paper
17 * _Twofish: A 128-Bit Block Cipher_ by Bruce 31 * _Twofish: A 128-Bit Block Cipher_ by Bruce Schneier, John Kelsey,
18 * Doug Whiting, David Wagner, Chris Hall, and 32 * Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson, available
19 * through http://www.counterpane.com/twofish. 33 * through http://www.counterpane.com/twofish.html
20 * 34 *
21 * For background information on multiplicatio 35 * For background information on multiplication in finite fields, used for
22 * the matrix operations in the key schedule, 36 * the matrix operations in the key schedule, see the book _Contemporary
23 * Abstract Algebra_ by Joseph A. Gallian, esp 37 * Abstract Algebra_ by Joseph A. Gallian, especially chapter 22 in the
24 * Third Edition. 38 * Third Edition.
25 */ 39 */
26 40
27 #include <linux/unaligned.h> !! 41 #include <asm/byteorder.h>
28 #include <crypto/algapi.h> <<
29 #include <crypto/twofish.h> 42 #include <crypto/twofish.h>
30 #include <linux/module.h> 43 #include <linux/module.h>
31 #include <linux/init.h> 44 #include <linux/init.h>
32 #include <linux/types.h> 45 #include <linux/types.h>
33 #include <linux/errno.h> 46 #include <linux/errno.h>
>> 47 #include <linux/crypto.h>
34 #include <linux/bitops.h> 48 #include <linux/bitops.h>
35 49
36 /* Macros to compute the g() function in the e 50 /* Macros to compute the g() function in the encryption and decryption
37 * rounds. G1 is the straight g() function; G 51 * rounds. G1 is the straight g() function; G2 includes the 8-bit
38 * rotation for the high 32-bit word. */ 52 * rotation for the high 32-bit word. */
39 53
40 #define G1(a) \ 54 #define G1(a) \
41 (ctx->s[0][(a) & 0xFF]) ^ (ctx->s[1][((a) 55 (ctx->s[0][(a) & 0xFF]) ^ (ctx->s[1][((a) >> 8) & 0xFF]) \
42 ^ (ctx->s[2][((a) >> 16) & 0xFF]) ^ (ctx->s 56 ^ (ctx->s[2][((a) >> 16) & 0xFF]) ^ (ctx->s[3][(a) >> 24])
43 57
44 #define G2(b) \ 58 #define G2(b) \
45 (ctx->s[1][(b) & 0xFF]) ^ (ctx->s[2][((b) 59 (ctx->s[1][(b) & 0xFF]) ^ (ctx->s[2][((b) >> 8) & 0xFF]) \
46 ^ (ctx->s[3][((b) >> 16) & 0xFF]) ^ (ctx->s 60 ^ (ctx->s[3][((b) >> 16) & 0xFF]) ^ (ctx->s[0][(b) >> 24])
47 61
48 /* Encryption and decryption Feistel rounds. 62 /* Encryption and decryption Feistel rounds. Each one calls the two g()
49 * macros, does the PHT, and performs the XOR 63 * macros, does the PHT, and performs the XOR and the appropriate bit
50 * rotations. The parameters are the round nu 64 * rotations. The parameters are the round number (used to select subkeys),
51 * and the four 32-bit chunks of the text. */ 65 * and the four 32-bit chunks of the text. */
52 66
53 #define ENCROUND(n, a, b, c, d) \ 67 #define ENCROUND(n, a, b, c, d) \
54 x = G1 (a); y = G2 (b); \ 68 x = G1 (a); y = G2 (b); \
55 x += y; y += x + ctx->k[2 * (n) + 1]; \ 69 x += y; y += x + ctx->k[2 * (n) + 1]; \
56 (c) ^= x + ctx->k[2 * (n)]; \ 70 (c) ^= x + ctx->k[2 * (n)]; \
57 (c) = ror32((c), 1); \ 71 (c) = ror32((c), 1); \
58 (d) = rol32((d), 1) ^ y 72 (d) = rol32((d), 1) ^ y
59 73
60 #define DECROUND(n, a, b, c, d) \ 74 #define DECROUND(n, a, b, c, d) \
61 x = G1 (a); y = G2 (b); \ 75 x = G1 (a); y = G2 (b); \
62 x += y; y += x; \ 76 x += y; y += x; \
63 (d) ^= y + ctx->k[2 * (n) + 1]; \ 77 (d) ^= y + ctx->k[2 * (n) + 1]; \
64 (d) = ror32((d), 1); \ 78 (d) = ror32((d), 1); \
65 (c) = rol32((c), 1); \ 79 (c) = rol32((c), 1); \
66 (c) ^= (x + ctx->k[2 * (n)]) 80 (c) ^= (x + ctx->k[2 * (n)])
67 81
68 /* Encryption and decryption cycles; each one 82 /* Encryption and decryption cycles; each one is simply two Feistel rounds
69 * with the 32-bit chunks re-ordered to simula 83 * with the 32-bit chunks re-ordered to simulate the "swap" */
70 84
71 #define ENCCYCLE(n) \ 85 #define ENCCYCLE(n) \
72 ENCROUND (2 * (n), a, b, c, d); \ 86 ENCROUND (2 * (n), a, b, c, d); \
73 ENCROUND (2 * (n) + 1, c, d, a, b) 87 ENCROUND (2 * (n) + 1, c, d, a, b)
74 88
75 #define DECCYCLE(n) \ 89 #define DECCYCLE(n) \
76 DECROUND (2 * (n) + 1, c, d, a, b); \ 90 DECROUND (2 * (n) + 1, c, d, a, b); \
77 DECROUND (2 * (n), a, b, c, d) 91 DECROUND (2 * (n), a, b, c, d)
78 92
79 /* Macros to convert the input and output byte 93 /* Macros to convert the input and output bytes into 32-bit words,
80 * and simultaneously perform the whitening st 94 * and simultaneously perform the whitening step. INPACK packs word
81 * number n into the variable named by x, usin 95 * number n into the variable named by x, using whitening subkey number m.
82 * OUTUNPACK unpacks word number n from the va 96 * OUTUNPACK unpacks word number n from the variable named by x, using
83 * whitening subkey number m. */ 97 * whitening subkey number m. */
84 98
85 #define INPACK(n, x, m) \ 99 #define INPACK(n, x, m) \
86 x = get_unaligned_le32(in + (n) * 4) ^ ctx- !! 100 x = le32_to_cpu(src[n]) ^ ctx->w[m]
87 101
88 #define OUTUNPACK(n, x, m) \ 102 #define OUTUNPACK(n, x, m) \
89 x ^= ctx->w[m]; \ 103 x ^= ctx->w[m]; \
90 put_unaligned_le32(x, out + (n) * 4) !! 104 dst[n] = cpu_to_le32(x)
91 105
92 106
93 107
94 /* Encrypt one block. in and out may be the s 108 /* Encrypt one block. in and out may be the same. */
95 static void twofish_encrypt(struct crypto_tfm 109 static void twofish_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
96 { 110 {
97 struct twofish_ctx *ctx = crypto_tfm_c 111 struct twofish_ctx *ctx = crypto_tfm_ctx(tfm);
>> 112 const __le32 *src = (const __le32 *)in;
>> 113 __le32 *dst = (__le32 *)out;
98 114
99 /* The four 32-bit chunks of the text. 115 /* The four 32-bit chunks of the text. */
100 u32 a, b, c, d; 116 u32 a, b, c, d;
101 117
102 /* Temporaries used by the round funct 118 /* Temporaries used by the round function. */
103 u32 x, y; 119 u32 x, y;
104 120
105 /* Input whitening and packing. */ 121 /* Input whitening and packing. */
106 INPACK (0, a, 0); 122 INPACK (0, a, 0);
107 INPACK (1, b, 1); 123 INPACK (1, b, 1);
108 INPACK (2, c, 2); 124 INPACK (2, c, 2);
109 INPACK (3, d, 3); 125 INPACK (3, d, 3);
110 126
111 /* Encryption Feistel cycles. */ 127 /* Encryption Feistel cycles. */
112 ENCCYCLE (0); 128 ENCCYCLE (0);
113 ENCCYCLE (1); 129 ENCCYCLE (1);
114 ENCCYCLE (2); 130 ENCCYCLE (2);
115 ENCCYCLE (3); 131 ENCCYCLE (3);
116 ENCCYCLE (4); 132 ENCCYCLE (4);
117 ENCCYCLE (5); 133 ENCCYCLE (5);
118 ENCCYCLE (6); 134 ENCCYCLE (6);
119 ENCCYCLE (7); 135 ENCCYCLE (7);
120 136
121 /* Output whitening and unpacking. */ 137 /* Output whitening and unpacking. */
122 OUTUNPACK (0, c, 4); 138 OUTUNPACK (0, c, 4);
123 OUTUNPACK (1, d, 5); 139 OUTUNPACK (1, d, 5);
124 OUTUNPACK (2, a, 6); 140 OUTUNPACK (2, a, 6);
125 OUTUNPACK (3, b, 7); 141 OUTUNPACK (3, b, 7);
126 142
127 } 143 }
128 144
129 /* Decrypt one block. in and out may be the s 145 /* Decrypt one block. in and out may be the same. */
130 static void twofish_decrypt(struct crypto_tfm 146 static void twofish_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
131 { 147 {
132 struct twofish_ctx *ctx = crypto_tfm_c 148 struct twofish_ctx *ctx = crypto_tfm_ctx(tfm);
>> 149 const __le32 *src = (const __le32 *)in;
>> 150 __le32 *dst = (__le32 *)out;
133 151
134 /* The four 32-bit chunks of the text. 152 /* The four 32-bit chunks of the text. */
135 u32 a, b, c, d; 153 u32 a, b, c, d;
136 154
137 /* Temporaries used by the round funct 155 /* Temporaries used by the round function. */
138 u32 x, y; 156 u32 x, y;
139 157
140 /* Input whitening and packing. */ 158 /* Input whitening and packing. */
141 INPACK (0, c, 4); 159 INPACK (0, c, 4);
142 INPACK (1, d, 5); 160 INPACK (1, d, 5);
143 INPACK (2, a, 6); 161 INPACK (2, a, 6);
144 INPACK (3, b, 7); 162 INPACK (3, b, 7);
145 163
146 /* Encryption Feistel cycles. */ 164 /* Encryption Feistel cycles. */
147 DECCYCLE (7); 165 DECCYCLE (7);
148 DECCYCLE (6); 166 DECCYCLE (6);
149 DECCYCLE (5); 167 DECCYCLE (5);
150 DECCYCLE (4); 168 DECCYCLE (4);
151 DECCYCLE (3); 169 DECCYCLE (3);
152 DECCYCLE (2); 170 DECCYCLE (2);
153 DECCYCLE (1); 171 DECCYCLE (1);
154 DECCYCLE (0); 172 DECCYCLE (0);
155 173
156 /* Output whitening and unpacking. */ 174 /* Output whitening and unpacking. */
157 OUTUNPACK (0, a, 0); 175 OUTUNPACK (0, a, 0);
158 OUTUNPACK (1, b, 1); 176 OUTUNPACK (1, b, 1);
159 OUTUNPACK (2, c, 2); 177 OUTUNPACK (2, c, 2);
160 OUTUNPACK (3, d, 3); 178 OUTUNPACK (3, d, 3);
161 179
162 } 180 }
163 181
164 static struct crypto_alg alg = { 182 static struct crypto_alg alg = {
165 .cra_name = "twofish", 183 .cra_name = "twofish",
166 .cra_driver_name = "twofish-gener 184 .cra_driver_name = "twofish-generic",
167 .cra_priority = 100, 185 .cra_priority = 100,
168 .cra_flags = CRYPTO_ALG_TYP 186 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
169 .cra_blocksize = TF_BLOCK_SIZE, 187 .cra_blocksize = TF_BLOCK_SIZE,
170 .cra_ctxsize = sizeof(struct 188 .cra_ctxsize = sizeof(struct twofish_ctx),
>> 189 .cra_alignmask = 3,
171 .cra_module = THIS_MODULE, 190 .cra_module = THIS_MODULE,
172 .cra_u = { .cipher = { 191 .cra_u = { .cipher = {
173 .cia_min_keysize = TF_MIN_KEY_SIZ 192 .cia_min_keysize = TF_MIN_KEY_SIZE,
174 .cia_max_keysize = TF_MAX_KEY_SIZ 193 .cia_max_keysize = TF_MAX_KEY_SIZE,
175 .cia_setkey = twofish_setkey 194 .cia_setkey = twofish_setkey,
176 .cia_encrypt = twofish_encryp 195 .cia_encrypt = twofish_encrypt,
177 .cia_decrypt = twofish_decryp 196 .cia_decrypt = twofish_decrypt } }
178 }; 197 };
179 198
180 static int __init twofish_mod_init(void) 199 static int __init twofish_mod_init(void)
181 { 200 {
182 return crypto_register_alg(&alg); 201 return crypto_register_alg(&alg);
183 } 202 }
184 203
185 static void __exit twofish_mod_fini(void) 204 static void __exit twofish_mod_fini(void)
186 { 205 {
187 crypto_unregister_alg(&alg); 206 crypto_unregister_alg(&alg);
188 } 207 }
189 208
190 subsys_initcall(twofish_mod_init); !! 209 module_init(twofish_mod_init);
191 module_exit(twofish_mod_fini); 210 module_exit(twofish_mod_fini);
192 211
193 MODULE_LICENSE("GPL"); 212 MODULE_LICENSE("GPL");
194 MODULE_DESCRIPTION ("Twofish Cipher Algorithm" 213 MODULE_DESCRIPTION ("Twofish Cipher Algorithm");
195 MODULE_ALIAS_CRYPTO("twofish"); 214 MODULE_ALIAS_CRYPTO("twofish");
196 MODULE_ALIAS_CRYPTO("twofish-generic"); 215 MODULE_ALIAS_CRYPTO("twofish-generic");
197 216
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