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#include <linux/init.h>
15#include <linux/module.h>
16#include <linux/mm.h>
17#include <asm/byteorder.h>
18#include <linux/crypto.h>
19#include <linux/types.h>
20#include <crypto/blowfish.h>
21
22/*
23 * Round loop unrolling macros, S is a pointer to a S-Box array
24 * organized in 4 unsigned longs at a row.
25 */
26#define GET32_3(x) (((x) & 0xff))
27#define GET32_2(x) (((x) >> (8)) & (0xff))
28#define GET32_1(x) (((x) >> (16)) & (0xff))
29#define GET32_0(x) (((x) >> (24)) & (0xff))
30
31#define bf_F(x) (((S[GET32_0(x)] + S[256 + GET32_1(x)]) ^ \
32		S[512 + GET32_2(x)]) + S[768 + GET32_3(x)])
33
34#define ROUND(a, b, n) ({ b ^= P[n]; a ^= bf_F(b); })
35
36static void bf_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
37{
38	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
39	const __be32 *in_blk = (const __be32 *)src;
40	__be32 *const out_blk = (__be32 *)dst;
41	const u32 *P = ctx->p;
42	const u32 *S = ctx->s;
43	u32 yl = be32_to_cpu(in_blk[0]);
44	u32 yr = be32_to_cpu(in_blk[1]);
45
46	ROUND(yr, yl, 0);
47	ROUND(yl, yr, 1);
48	ROUND(yr, yl, 2);
49	ROUND(yl, yr, 3);
50	ROUND(yr, yl, 4);
51	ROUND(yl, yr, 5);
52	ROUND(yr, yl, 6);
53	ROUND(yl, yr, 7);
54	ROUND(yr, yl, 8);
55	ROUND(yl, yr, 9);
56	ROUND(yr, yl, 10);
57	ROUND(yl, yr, 11);
58	ROUND(yr, yl, 12);
59	ROUND(yl, yr, 13);
60	ROUND(yr, yl, 14);
61	ROUND(yl, yr, 15);
62
63	yl ^= P[16];
64	yr ^= P[17];
65
66	out_blk[0] = cpu_to_be32(yr);
67	out_blk[1] = cpu_to_be32(yl);
68}
69
70static void bf_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
71{
72	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
73	const __be32 *in_blk = (const __be32 *)src;
74	__be32 *const out_blk = (__be32 *)dst;
75	const u32 *P = ctx->p;
76	const u32 *S = ctx->s;
77	u32 yl = be32_to_cpu(in_blk[0]);
78	u32 yr = be32_to_cpu(in_blk[1]);
79
80	ROUND(yr, yl, 17);
81	ROUND(yl, yr, 16);
82	ROUND(yr, yl, 15);
83	ROUND(yl, yr, 14);
84	ROUND(yr, yl, 13);
85	ROUND(yl, yr, 12);
86	ROUND(yr, yl, 11);
87	ROUND(yl, yr, 10);
88	ROUND(yr, yl, 9);
89	ROUND(yl, yr, 8);
90	ROUND(yr, yl, 7);
91	ROUND(yl, yr, 6);
92	ROUND(yr, yl, 5);
93	ROUND(yl, yr, 4);
94	ROUND(yr, yl, 3);
95	ROUND(yl, yr, 2);
96
97	yl ^= P[1];
98	yr ^= P[0];
99
100	out_blk[0] = cpu_to_be32(yr);
101	out_blk[1] = cpu_to_be32(yl);
102}
103
104static struct crypto_alg alg = {
105	.cra_name		=	"blowfish",
106	.cra_driver_name	=	"blowfish-generic",
107	.cra_priority		=	100,
108	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
109	.cra_blocksize		=	BF_BLOCK_SIZE,
110	.cra_ctxsize		=	sizeof(struct bf_ctx),
111	.cra_alignmask		=	3,
112	.cra_module		=	THIS_MODULE,
113	.cra_u			=	{ .cipher = {
114	.cia_min_keysize	=	BF_MIN_KEY_SIZE,
115	.cia_max_keysize	=	BF_MAX_KEY_SIZE,
116	.cia_setkey		=	blowfish_setkey,
117	.cia_encrypt		=	bf_encrypt,
118	.cia_decrypt		=	bf_decrypt } }
119};
120
121static int __init blowfish_mod_init(void)
122{
123	return crypto_register_alg(&alg);
124}
125
126static void __exit blowfish_mod_fini(void)
127{
128	crypto_unregister_alg(&alg);
129}
130
131subsys_initcall(blowfish_mod_init);
132module_exit(blowfish_mod_fini);
133
134MODULE_LICENSE("GPL");
135MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
136MODULE_ALIAS_CRYPTO("blowfish");
137MODULE_ALIAS_CRYPTO("blowfish-generic");
138