1 // SPDX-License-Identifier: GPL-2.0-or-later <<
2 /* 1 /*
3 * Cryptographic API 2 * Cryptographic API
4 * 3 *
5 * ARC4 Cipher Algorithm 4 * ARC4 Cipher Algorithm
6 * 5 *
7 * Jon Oberheide <jon@oberheide.org> 6 * Jon Oberheide <jon@oberheide.org>
>> 7 *
>> 8 * This program is free software; you can redistribute it and/or modify
>> 9 * it under the terms of the GNU General Public License as published by
>> 10 * the Free Software Foundation; either version 2 of the License, or
>> 11 * (at your option) any later version.
>> 12 *
8 */ 13 */
9 14
>> 15 #include <crypto/algapi.h>
10 #include <crypto/arc4.h> 16 #include <crypto/arc4.h>
11 #include <crypto/internal/skcipher.h> 17 #include <crypto/internal/skcipher.h>
12 #include <linux/init.h> 18 #include <linux/init.h>
13 #include <linux/kernel.h> <<
14 #include <linux/module.h> 19 #include <linux/module.h>
15 #include <linux/sched.h> <<
16 20
17 #define ARC4_ALIGN __alignof__(struct arc4_ctx !! 21 struct arc4_ctx {
>> 22 u32 S[256];
>> 23 u32 x, y;
>> 24 };
18 25
19 static int crypto_arc4_setkey(struct crypto_ls !! 26 static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
20 unsigned int key !! 27 unsigned int key_len)
21 { 28 {
22 struct arc4_ctx *ctx = crypto_lskciphe !! 29 struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
>> 30 int i, j = 0, k = 0;
>> 31
>> 32 ctx->x = 1;
>> 33 ctx->y = 0;
23 34
24 return arc4_setkey(ctx, in_key, key_le !! 35 for (i = 0; i < 256; i++)
>> 36 ctx->S[i] = i;
>> 37
>> 38 for (i = 0; i < 256; i++) {
>> 39 u32 a = ctx->S[i];
>> 40 j = (j + in_key[k] + a) & 0xff;
>> 41 ctx->S[i] = ctx->S[j];
>> 42 ctx->S[j] = a;
>> 43 if (++k >= key_len)
>> 44 k = 0;
>> 45 }
>> 46
>> 47 return 0;
25 } 48 }
26 49
27 static int crypto_arc4_crypt(struct crypto_lsk !! 50 static int arc4_set_key_skcipher(struct crypto_skcipher *tfm, const u8 *in_key,
28 u8 *dst, unsigned !! 51 unsigned int key_len)
29 { 52 {
30 struct arc4_ctx *ctx = crypto_lskciphe !! 53 return arc4_set_key(&tfm->base, in_key, key_len);
>> 54 }
31 55
32 if (!(flags & CRYPTO_LSKCIPHER_FLAG_CO !! 56 static void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in,
33 memcpy(siv, ctx, sizeof(*ctx)) !! 57 unsigned int len)
>> 58 {
>> 59 u32 *const S = ctx->S;
>> 60 u32 x, y, a, b;
>> 61 u32 ty, ta, tb;
>> 62
>> 63 if (len == 0)
>> 64 return;
>> 65
>> 66 x = ctx->x;
>> 67 y = ctx->y;
>> 68
>> 69 a = S[x];
>> 70 y = (y + a) & 0xff;
>> 71 b = S[y];
>> 72
>> 73 do {
>> 74 S[y] = a;
>> 75 a = (a + b) & 0xff;
>> 76 S[x] = b;
>> 77 x = (x + 1) & 0xff;
>> 78 ta = S[x];
>> 79 ty = (y + ta) & 0xff;
>> 80 tb = S[ty];
>> 81 *out++ = *in++ ^ S[a];
>> 82 if (--len == 0)
>> 83 break;
>> 84 y = ty;
>> 85 a = ta;
>> 86 b = tb;
>> 87 } while (true);
34 88
35 ctx = (struct arc4_ctx *)siv; !! 89 ctx->x = x;
>> 90 ctx->y = y;
>> 91 }
36 92
37 arc4_crypt(ctx, dst, src, nbytes); !! 93 static void arc4_crypt_one(struct crypto_tfm *tfm, u8 *out, const u8 *in)
38 return 0; !! 94 {
>> 95 arc4_crypt(crypto_tfm_ctx(tfm), out, in, 1);
39 } 96 }
40 97
41 static int crypto_arc4_init(struct crypto_lskc !! 98 static int ecb_arc4_crypt(struct skcipher_request *req)
42 { 99 {
43 pr_warn_ratelimited("\"%s\" (%ld) uses !! 100 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
44 current->comm, (un !! 101 struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
>> 102 struct skcipher_walk walk;
>> 103 int err;
>> 104
>> 105 err = skcipher_walk_virt(&walk, req, false);
>> 106
>> 107 while (walk.nbytes > 0) {
>> 108 arc4_crypt(ctx, walk.dst.virt.addr, walk.src.virt.addr,
>> 109 walk.nbytes);
>> 110 err = skcipher_walk_done(&walk, 0);
>> 111 }
45 112
46 return 0; !! 113 return err;
47 } 114 }
48 115
49 static struct lskcipher_alg arc4_alg = { !! 116 static struct crypto_alg arc4_cipher = {
50 .co.base.cra_name = !! 117 .cra_name = "arc4",
51 .co.base.cra_driver_name = !! 118 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
52 .co.base.cra_priority = !! 119 .cra_blocksize = ARC4_BLOCK_SIZE,
53 .co.base.cra_blocksize = !! 120 .cra_ctxsize = sizeof(struct arc4_ctx),
54 .co.base.cra_ctxsize = !! 121 .cra_module = THIS_MODULE,
55 .co.base.cra_alignmask = !! 122 .cra_u = {
56 .co.base.cra_module = !! 123 .cipher = {
57 .co.min_keysize = !! 124 .cia_min_keysize = ARC4_MIN_KEY_SIZE,
58 .co.max_keysize = !! 125 .cia_max_keysize = ARC4_MAX_KEY_SIZE,
59 .co.statesize = !! 126 .cia_setkey = arc4_set_key,
60 .setkey = !! 127 .cia_encrypt = arc4_crypt_one,
61 .encrypt = !! 128 .cia_decrypt = arc4_crypt_one,
62 .decrypt = !! 129 },
63 .init = !! 130 },
>> 131 };
>> 132
>> 133 static struct skcipher_alg arc4_skcipher = {
>> 134 .base.cra_name = "ecb(arc4)",
>> 135 .base.cra_priority = 100,
>> 136 .base.cra_blocksize = ARC4_BLOCK_SIZE,
>> 137 .base.cra_ctxsize = sizeof(struct arc4_ctx),
>> 138 .base.cra_module = THIS_MODULE,
>> 139 .min_keysize = ARC4_MIN_KEY_SIZE,
>> 140 .max_keysize = ARC4_MAX_KEY_SIZE,
>> 141 .setkey = arc4_set_key_skcipher,
>> 142 .encrypt = ecb_arc4_crypt,
>> 143 .decrypt = ecb_arc4_crypt,
64 }; 144 };
65 145
66 static int __init arc4_init(void) 146 static int __init arc4_init(void)
67 { 147 {
68 return crypto_register_lskcipher(&arc4 !! 148 int err;
>> 149
>> 150 err = crypto_register_alg(&arc4_cipher);
>> 151 if (err)
>> 152 return err;
>> 153
>> 154 err = crypto_register_skcipher(&arc4_skcipher);
>> 155 if (err)
>> 156 crypto_unregister_alg(&arc4_cipher);
>> 157 return err;
69 } 158 }
70 159
71 static void __exit arc4_exit(void) 160 static void __exit arc4_exit(void)
72 { 161 {
73 crypto_unregister_lskcipher(&arc4_alg) !! 162 crypto_unregister_alg(&arc4_cipher);
>> 163 crypto_unregister_skcipher(&arc4_skcipher);
74 } 164 }
75 165
76 subsys_initcall(arc4_init); !! 166 module_init(arc4_init);
77 module_exit(arc4_exit); 167 module_exit(arc4_exit);
78 168
79 MODULE_LICENSE("GPL"); 169 MODULE_LICENSE("GPL");
80 MODULE_DESCRIPTION("ARC4 Cipher Algorithm"); 170 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
81 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.or 171 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
82 MODULE_ALIAS_CRYPTO("ecb(arc4)"); !! 172 MODULE_ALIAS_CRYPTO("arc4");
83 173
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