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
10 #include <crypto/arc4.h> <<
11 #include <crypto/internal/skcipher.h> <<
12 #include <linux/init.h> <<
13 #include <linux/kernel.h> <<
14 #include <linux/module.h> 15 #include <linux/module.h>
15 #include <linux/sched.h> !! 16 #include <linux/init.h>
>> 17 #include <linux/crypto.h>
>> 18 #include <crypto/algapi.h>
16 19
17 #define ARC4_ALIGN __alignof__(struct arc4_ctx !! 20 #define ARC4_MIN_KEY_SIZE 1
>> 21 #define ARC4_MAX_KEY_SIZE 256
>> 22 #define ARC4_BLOCK_SIZE 1
>> 23
>> 24 struct arc4_ctx {
>> 25 u32 S[256];
>> 26 u32 x, y;
>> 27 };
18 28
19 static int crypto_arc4_setkey(struct crypto_ls !! 29 static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
20 unsigned int key !! 30 unsigned int key_len)
21 { 31 {
22 struct arc4_ctx *ctx = crypto_lskciphe !! 32 struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
>> 33 int i, j = 0, k = 0;
23 34
24 return arc4_setkey(ctx, in_key, key_le !! 35 ctx->x = 1;
>> 36 ctx->y = 0;
>> 37
>> 38 for (i = 0; i < 256; i++)
>> 39 ctx->S[i] = i;
>> 40
>> 41 for (i = 0; i < 256; i++) {
>> 42 u32 a = ctx->S[i];
>> 43 j = (j + in_key[k] + a) & 0xff;
>> 44 ctx->S[i] = ctx->S[j];
>> 45 ctx->S[j] = a;
>> 46 if (++k >= key_len)
>> 47 k = 0;
>> 48 }
>> 49
>> 50 return 0;
25 } 51 }
26 52
27 static int crypto_arc4_crypt(struct crypto_lsk !! 53 static void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in,
28 u8 *dst, unsigned !! 54 unsigned int len)
29 { 55 {
30 struct arc4_ctx *ctx = crypto_lskciphe !! 56 u32 *const S = ctx->S;
31 !! 57 u32 x, y, a, b;
32 if (!(flags & CRYPTO_LSKCIPHER_FLAG_CO !! 58 u32 ty, ta, tb;
33 memcpy(siv, ctx, sizeof(*ctx)) !! 59
>> 60 if (len == 0)
>> 61 return;
>> 62
>> 63 x = ctx->x;
>> 64 y = ctx->y;
>> 65
>> 66 a = S[x];
>> 67 y = (y + a) & 0xff;
>> 68 b = S[y];
>> 69
>> 70 do {
>> 71 S[y] = a;
>> 72 a = (a + b) & 0xff;
>> 73 S[x] = b;
>> 74 x = (x + 1) & 0xff;
>> 75 ta = S[x];
>> 76 ty = (y + ta) & 0xff;
>> 77 tb = S[ty];
>> 78 *out++ = *in++ ^ S[a];
>> 79 if (--len == 0)
>> 80 break;
>> 81 y = ty;
>> 82 a = ta;
>> 83 b = tb;
>> 84 } while (true);
34 85
35 ctx = (struct arc4_ctx *)siv; !! 86 ctx->x = x;
>> 87 ctx->y = y;
>> 88 }
36 89
37 arc4_crypt(ctx, dst, src, nbytes); !! 90 static void arc4_crypt_one(struct crypto_tfm *tfm, u8 *out, const u8 *in)
38 return 0; !! 91 {
>> 92 arc4_crypt(crypto_tfm_ctx(tfm), out, in, 1);
39 } 93 }
40 94
41 static int crypto_arc4_init(struct crypto_lskc !! 95 static int ecb_arc4_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
>> 96 struct scatterlist *src, unsigned int nbytes)
42 { 97 {
43 pr_warn_ratelimited("\"%s\" (%ld) uses !! 98 struct arc4_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
44 current->comm, (un !! 99 struct blkcipher_walk walk;
>> 100 int err;
45 101
46 return 0; !! 102 blkcipher_walk_init(&walk, dst, src, nbytes);
>> 103
>> 104 err = blkcipher_walk_virt(desc, &walk);
>> 105
>> 106 while (walk.nbytes > 0) {
>> 107 u8 *wsrc = walk.src.virt.addr;
>> 108 u8 *wdst = walk.dst.virt.addr;
>> 109
>> 110 arc4_crypt(ctx, wdst, wsrc, walk.nbytes);
>> 111
>> 112 err = blkcipher_walk_done(desc, &walk, 0);
>> 113 }
>> 114
>> 115 return err;
47 } 116 }
48 117
49 static struct lskcipher_alg arc4_alg = { !! 118 static struct crypto_alg arc4_algs[2] = { {
50 .co.base.cra_name = !! 119 .cra_name = "arc4",
51 .co.base.cra_driver_name = !! 120 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
52 .co.base.cra_priority = !! 121 .cra_blocksize = ARC4_BLOCK_SIZE,
53 .co.base.cra_blocksize = !! 122 .cra_ctxsize = sizeof(struct arc4_ctx),
54 .co.base.cra_ctxsize = !! 123 .cra_module = THIS_MODULE,
55 .co.base.cra_alignmask = !! 124 .cra_u = {
56 .co.base.cra_module = !! 125 .cipher = {
57 .co.min_keysize = !! 126 .cia_min_keysize = ARC4_MIN_KEY_SIZE,
58 .co.max_keysize = !! 127 .cia_max_keysize = ARC4_MAX_KEY_SIZE,
59 .co.statesize = !! 128 .cia_setkey = arc4_set_key,
60 .setkey = !! 129 .cia_encrypt = arc4_crypt_one,
61 .encrypt = !! 130 .cia_decrypt = arc4_crypt_one,
62 .decrypt = !! 131 },
63 .init = !! 132 },
64 }; !! 133 }, {
>> 134 .cra_name = "ecb(arc4)",
>> 135 .cra_priority = 100,
>> 136 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
>> 137 .cra_blocksize = ARC4_BLOCK_SIZE,
>> 138 .cra_ctxsize = sizeof(struct arc4_ctx),
>> 139 .cra_alignmask = 0,
>> 140 .cra_type = &crypto_blkcipher_type,
>> 141 .cra_module = THIS_MODULE,
>> 142 .cra_u = {
>> 143 .blkcipher = {
>> 144 .min_keysize = ARC4_MIN_KEY_SIZE,
>> 145 .max_keysize = ARC4_MAX_KEY_SIZE,
>> 146 .setkey = arc4_set_key,
>> 147 .encrypt = ecb_arc4_crypt,
>> 148 .decrypt = ecb_arc4_crypt,
>> 149 },
>> 150 },
>> 151 } };
65 152
66 static int __init arc4_init(void) 153 static int __init arc4_init(void)
67 { 154 {
68 return crypto_register_lskcipher(&arc4 !! 155 return crypto_register_algs(arc4_algs, ARRAY_SIZE(arc4_algs));
69 } 156 }
70 157
71 static void __exit arc4_exit(void) 158 static void __exit arc4_exit(void)
72 { 159 {
73 crypto_unregister_lskcipher(&arc4_alg) !! 160 crypto_unregister_algs(arc4_algs, ARRAY_SIZE(arc4_algs));
74 } 161 }
75 162
76 subsys_initcall(arc4_init); !! 163 module_init(arc4_init);
77 module_exit(arc4_exit); 164 module_exit(arc4_exit);
78 165
79 MODULE_LICENSE("GPL"); 166 MODULE_LICENSE("GPL");
80 MODULE_DESCRIPTION("ARC4 Cipher Algorithm"); 167 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
81 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.or 168 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
82 MODULE_ALIAS_CRYPTO("ecb(arc4)"); !! 169 MODULE_ALIAS_CRYPTO("arc4");
83 170
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