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