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 
bf_encrypt(struct crypto_tfm * tfm,u8 * dst,const u8 * src)37 static 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 
bf_decrypt(struct crypto_tfm * tfm,u8 * dst,const u8 * src)69 static 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 
101 static 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 
blowfish_mod_init(void)117 static int __init blowfish_mod_init(void)
118 {
119 	return crypto_register_alg(&alg);
120 }
121 
blowfish_mod_fini(void)122 static void __exit blowfish_mod_fini(void)
123 {
124 	crypto_unregister_alg(&alg);
125 }
126 
127 subsys_initcall(blowfish_mod_init);
128 module_exit(blowfish_mod_fini);
129 
130 MODULE_LICENSE("GPL");
131 MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
132 MODULE_ALIAS_CRYPTO("blowfish");
133 MODULE_ALIAS_CRYPTO("blowfish-generic");
134