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/kernel.h>
15 #include <linux/module.h>
16 #include <linux/sched.h>
17
crypto_arc4_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)18 static int crypto_arc4_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
19 unsigned int key_len)
20 {
21 struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
22
23 return arc4_setkey(ctx, in_key, key_len);
24 }
25
crypto_arc4_crypt(struct skcipher_request * req)26 static int crypto_arc4_crypt(struct skcipher_request *req)
27 {
28 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
29 struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
30 struct skcipher_walk walk;
31 int err;
32
33 err = skcipher_walk_virt(&walk, req, false);
34
35 while (walk.nbytes > 0) {
36 arc4_crypt(ctx, walk.dst.virt.addr, walk.src.virt.addr,
37 walk.nbytes);
38 err = skcipher_walk_done(&walk, 0);
39 }
40
41 return err;
42 }
43
crypto_arc4_init(struct crypto_skcipher * tfm)44 static int crypto_arc4_init(struct crypto_skcipher *tfm)
45 {
46 pr_warn_ratelimited("\"%s\" (%ld) uses obsolete ecb(arc4) skcipher\n",
47 current->comm, (unsigned long)current->pid);
48
49 return 0;
50 }
51
52 static struct skcipher_alg arc4_alg = {
53 /*
54 * For legacy reasons, this is named "ecb(arc4)", not "arc4".
55 * Nevertheless it's actually a stream cipher, not a block cipher.
56 */
57 .base.cra_name = "ecb(arc4)",
58 .base.cra_driver_name = "ecb(arc4)-generic",
59 .base.cra_priority = 100,
60 .base.cra_blocksize = ARC4_BLOCK_SIZE,
61 .base.cra_ctxsize = sizeof(struct arc4_ctx),
62 .base.cra_module = THIS_MODULE,
63 .min_keysize = ARC4_MIN_KEY_SIZE,
64 .max_keysize = ARC4_MAX_KEY_SIZE,
65 .setkey = crypto_arc4_setkey,
66 .encrypt = crypto_arc4_crypt,
67 .decrypt = crypto_arc4_crypt,
68 .init = crypto_arc4_init,
69 };
70
arc4_init(void)71 static int __init arc4_init(void)
72 {
73 return crypto_register_skcipher(&arc4_alg);
74 }
75
arc4_exit(void)76 static void __exit arc4_exit(void)
77 {
78 crypto_unregister_skcipher(&arc4_alg);
79 }
80
81 subsys_initcall(arc4_init);
82 module_exit(arc4_exit);
83
84 MODULE_LICENSE("GPL");
85 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
86 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
87 MODULE_ALIAS_CRYPTO("ecb(arc4)");
88