1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Cryptographic API
4 *
5 * ARC4 Cipher Algorithm
6 *
7 * Jon Oberheide <jon@oberheide.org>
8 */
9
10 #include <crypto/algapi.h>
11 #include <crypto/arc4.h>
12 #include <crypto/internal/skcipher.h>
13 #include <linux/init.h>
14 #include <linux/module.h>
15
crypto_arc4_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)16 static int crypto_arc4_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
17 unsigned int key_len)
18 {
19 struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
20
21 return arc4_setkey(ctx, in_key, key_len);
22 }
23
crypto_arc4_crypt(struct skcipher_request * req)24 static int crypto_arc4_crypt(struct skcipher_request *req)
25 {
26 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
27 struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
28 struct skcipher_walk walk;
29 int err;
30
31 err = skcipher_walk_virt(&walk, req, false);
32
33 while (walk.nbytes > 0) {
34 arc4_crypt(ctx, walk.dst.virt.addr, walk.src.virt.addr,
35 walk.nbytes);
36 err = skcipher_walk_done(&walk, 0);
37 }
38
39 return err;
40 }
41
42 static struct skcipher_alg arc4_alg = {
43 /*
44 * For legacy reasons, this is named "ecb(arc4)", not "arc4".
45 * Nevertheless it's actually a stream cipher, not a block cipher.
46 */
47 .base.cra_name = "ecb(arc4)",
48 .base.cra_driver_name = "ecb(arc4)-generic",
49 .base.cra_priority = 100,
50 .base.cra_blocksize = ARC4_BLOCK_SIZE,
51 .base.cra_ctxsize = sizeof(struct arc4_ctx),
52 .base.cra_module = THIS_MODULE,
53 .min_keysize = ARC4_MIN_KEY_SIZE,
54 .max_keysize = ARC4_MAX_KEY_SIZE,
55 .setkey = crypto_arc4_setkey,
56 .encrypt = crypto_arc4_crypt,
57 .decrypt = crypto_arc4_crypt,
58 };
59
arc4_init(void)60 static int __init arc4_init(void)
61 {
62 return crypto_register_skcipher(&arc4_alg);
63 }
64
arc4_exit(void)65 static void __exit arc4_exit(void)
66 {
67 crypto_unregister_skcipher(&arc4_alg);
68 }
69
70 subsys_initcall(arc4_init);
71 module_exit(arc4_exit);
72
73 MODULE_LICENSE("GPL");
74 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
75 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
76 MODULE_ALIAS_CRYPTO("ecb(arc4)");
77