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/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/sched.h>
16
17#define ARC4_ALIGN __alignof__(struct arc4_ctx)
18
19static int crypto_arc4_setkey(struct crypto_lskcipher *tfm, const u8 *in_key,
20			      unsigned int key_len)
21{
22	struct arc4_ctx *ctx = crypto_lskcipher_ctx(tfm);
23
24	return arc4_setkey(ctx, in_key, key_len);
25}
26
27static int crypto_arc4_crypt(struct crypto_lskcipher *tfm, const u8 *src,
28			     u8 *dst, unsigned nbytes, u8 *siv, u32 flags)
29{
30	struct arc4_ctx *ctx = crypto_lskcipher_ctx(tfm);
31
32	if (!(flags & CRYPTO_LSKCIPHER_FLAG_CONT))
33		memcpy(siv, ctx, sizeof(*ctx));
34
35	ctx = (struct arc4_ctx *)siv;
36
37	arc4_crypt(ctx, dst, src, nbytes);
38	return 0;
39}
40
41static int crypto_arc4_init(struct crypto_lskcipher *tfm)
42{
43	pr_warn_ratelimited("\"%s\" (%ld) uses obsolete ecb(arc4) skcipher\n",
44			    current->comm, (unsigned long)current->pid);
45
46	return 0;
47}
48
49static struct lskcipher_alg arc4_alg = {
50	.co.base.cra_name		=	"arc4",
51	.co.base.cra_driver_name	=	"arc4-generic",
52	.co.base.cra_priority		=	100,
53	.co.base.cra_blocksize		=	ARC4_BLOCK_SIZE,
54	.co.base.cra_ctxsize		=	sizeof(struct arc4_ctx),
55	.co.base.cra_alignmask		=	ARC4_ALIGN - 1,
56	.co.base.cra_module		=	THIS_MODULE,
57	.co.min_keysize			=	ARC4_MIN_KEY_SIZE,
58	.co.max_keysize			=	ARC4_MAX_KEY_SIZE,
59	.co.statesize			=	sizeof(struct arc4_ctx),
60	.setkey				=	crypto_arc4_setkey,
61	.encrypt			=	crypto_arc4_crypt,
62	.decrypt			=	crypto_arc4_crypt,
63	.init				=	crypto_arc4_init,
64};
65
66static int __init arc4_init(void)
67{
68	return crypto_register_lskcipher(&arc4_alg);
69}
70
71static void __exit arc4_exit(void)
72{
73	crypto_unregister_lskcipher(&arc4_alg);
74}
75
76subsys_initcall(arc4_init);
77module_exit(arc4_exit);
78
79MODULE_LICENSE("GPL");
80MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
81MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
82MODULE_ALIAS_CRYPTO("ecb(arc4)");
83