1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Cryptographic API.
4 *
5 * Blowfish Cipher Algorithm, by Bruce Schneier.
6 * http://www.counterpane.com/blowfish.html
7 *
8 * Adapted from Kerneli implementation.
9 *
10 * Copyright (c) Herbert Valerio Riedel <hvr@hvrlab.org>
11 * Copyright (c) Kyle McMartin <kyle@debian.org>
12 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
13 */
14
15#include <crypto/algapi.h>
16#include <linux/init.h>
17#include <linux/module.h>
18#include <linux/mm.h>
19#include <asm/unaligned.h>
20#include <linux/types.h>
21#include <crypto/blowfish.h>
22
23/*
24 * Round loop unrolling macros, S is a pointer to a S-Box array
25 * organized in 4 unsigned longs at a row.
26 */
27#define GET32_3(x) (((x) & 0xff))
28#define GET32_2(x) (((x) >> (8)) & (0xff))
29#define GET32_1(x) (((x) >> (16)) & (0xff))
30#define GET32_0(x) (((x) >> (24)) & (0xff))
31
32#define bf_F(x) (((S[GET32_0(x)] + S[256 + GET32_1(x)]) ^ \
33		S[512 + GET32_2(x)]) + S[768 + GET32_3(x)])
34
35#define ROUND(a, b, n) ({ b ^= P[n]; a ^= bf_F(b); })
36
37static void bf_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
38{
39	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
40	const u32 *P = ctx->p;
41	const u32 *S = ctx->s;
42	u32 yl = get_unaligned_be32(src);
43	u32 yr = get_unaligned_be32(src + 4);
44
45	ROUND(yr, yl, 0);
46	ROUND(yl, yr, 1);
47	ROUND(yr, yl, 2);
48	ROUND(yl, yr, 3);
49	ROUND(yr, yl, 4);
50	ROUND(yl, yr, 5);
51	ROUND(yr, yl, 6);
52	ROUND(yl, yr, 7);
53	ROUND(yr, yl, 8);
54	ROUND(yl, yr, 9);
55	ROUND(yr, yl, 10);
56	ROUND(yl, yr, 11);
57	ROUND(yr, yl, 12);
58	ROUND(yl, yr, 13);
59	ROUND(yr, yl, 14);
60	ROUND(yl, yr, 15);
61
62	yl ^= P[16];
63	yr ^= P[17];
64
65	put_unaligned_be32(yr, dst);
66	put_unaligned_be32(yl, dst + 4);
67}
68
69static void bf_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
70{
71	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
72	const u32 *P = ctx->p;
73	const u32 *S = ctx->s;
74	u32 yl = get_unaligned_be32(src);
75	u32 yr = get_unaligned_be32(src + 4);
76
77	ROUND(yr, yl, 17);
78	ROUND(yl, yr, 16);
79	ROUND(yr, yl, 15);
80	ROUND(yl, yr, 14);
81	ROUND(yr, yl, 13);
82	ROUND(yl, yr, 12);
83	ROUND(yr, yl, 11);
84	ROUND(yl, yr, 10);
85	ROUND(yr, yl, 9);
86	ROUND(yl, yr, 8);
87	ROUND(yr, yl, 7);
88	ROUND(yl, yr, 6);
89	ROUND(yr, yl, 5);
90	ROUND(yl, yr, 4);
91	ROUND(yr, yl, 3);
92	ROUND(yl, yr, 2);
93
94	yl ^= P[1];
95	yr ^= P[0];
96
97	put_unaligned_be32(yr, dst);
98	put_unaligned_be32(yl, dst + 4);
99}
100
101static struct crypto_alg alg = {
102	.cra_name		=	"blowfish",
103	.cra_driver_name	=	"blowfish-generic",
104	.cra_priority		=	100,
105	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
106	.cra_blocksize		=	BF_BLOCK_SIZE,
107	.cra_ctxsize		=	sizeof(struct bf_ctx),
108	.cra_module		=	THIS_MODULE,
109	.cra_u			=	{ .cipher = {
110	.cia_min_keysize	=	BF_MIN_KEY_SIZE,
111	.cia_max_keysize	=	BF_MAX_KEY_SIZE,
112	.cia_setkey		=	blowfish_setkey,
113	.cia_encrypt		=	bf_encrypt,
114	.cia_decrypt		=	bf_decrypt } }
115};
116
117static int __init blowfish_mod_init(void)
118{
119	return crypto_register_alg(&alg);
120}
121
122static void __exit blowfish_mod_fini(void)
123{
124	crypto_unregister_alg(&alg);
125}
126
127subsys_initcall(blowfish_mod_init);
128module_exit(blowfish_mod_fini);
129
130MODULE_LICENSE("GPL");
131MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
132MODULE_ALIAS_CRYPTO("blowfish");
133MODULE_ALIAS_CRYPTO("blowfish-generic");
134