1 /*
2  * Cryptographic API.
3  *
4  * Blowfish Cipher Algorithm, by Bruce Schneier.
5  * http://www.counterpane.com/blowfish.html
6  *
7  * Adapted from Kerneli implementation.
8  *
9  * Copyright (c) Herbert Valerio Riedel <hvr@hvrlab.org>
10  * Copyright (c) Kyle McMartin <kyle@debian.org>
11  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License as published by
15  * the Free Software Foundation; either version 2 of the License, or
16  * (at your option) any later version.
17  *
18  */
19 #include <linux/init.h>
20 #include <linux/module.h>
21 #include <linux/mm.h>
22 #include <asm/byteorder.h>
23 #include <linux/crypto.h>
24 #include <linux/types.h>
25 #include <crypto/blowfish.h>
26 
27 /*
28  * Round loop unrolling macros, S is a pointer to a S-Box array
29  * organized in 4 unsigned longs at a row.
30  */
31 #define GET32_3(x) (((x) & 0xff))
32 #define GET32_2(x) (((x) >> (8)) & (0xff))
33 #define GET32_1(x) (((x) >> (16)) & (0xff))
34 #define GET32_0(x) (((x) >> (24)) & (0xff))
35 
36 #define bf_F(x) (((S[GET32_0(x)] + S[256 + GET32_1(x)]) ^ \
37 		S[512 + GET32_2(x)]) + S[768 + GET32_3(x)])
38 
39 #define ROUND(a, b, n) ({ b ^= P[n]; a ^= bf_F(b); })
40 
bf_encrypt(struct crypto_tfm * tfm,u8 * dst,const u8 * src)41 static void bf_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
42 {
43 	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
44 	const __be32 *in_blk = (const __be32 *)src;
45 	__be32 *const out_blk = (__be32 *)dst;
46 	const u32 *P = ctx->p;
47 	const u32 *S = ctx->s;
48 	u32 yl = be32_to_cpu(in_blk[0]);
49 	u32 yr = be32_to_cpu(in_blk[1]);
50 
51 	ROUND(yr, yl, 0);
52 	ROUND(yl, yr, 1);
53 	ROUND(yr, yl, 2);
54 	ROUND(yl, yr, 3);
55 	ROUND(yr, yl, 4);
56 	ROUND(yl, yr, 5);
57 	ROUND(yr, yl, 6);
58 	ROUND(yl, yr, 7);
59 	ROUND(yr, yl, 8);
60 	ROUND(yl, yr, 9);
61 	ROUND(yr, yl, 10);
62 	ROUND(yl, yr, 11);
63 	ROUND(yr, yl, 12);
64 	ROUND(yl, yr, 13);
65 	ROUND(yr, yl, 14);
66 	ROUND(yl, yr, 15);
67 
68 	yl ^= P[16];
69 	yr ^= P[17];
70 
71 	out_blk[0] = cpu_to_be32(yr);
72 	out_blk[1] = cpu_to_be32(yl);
73 }
74 
bf_decrypt(struct crypto_tfm * tfm,u8 * dst,const u8 * src)75 static void bf_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
76 {
77 	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
78 	const __be32 *in_blk = (const __be32 *)src;
79 	__be32 *const out_blk = (__be32 *)dst;
80 	const u32 *P = ctx->p;
81 	const u32 *S = ctx->s;
82 	u32 yl = be32_to_cpu(in_blk[0]);
83 	u32 yr = be32_to_cpu(in_blk[1]);
84 
85 	ROUND(yr, yl, 17);
86 	ROUND(yl, yr, 16);
87 	ROUND(yr, yl, 15);
88 	ROUND(yl, yr, 14);
89 	ROUND(yr, yl, 13);
90 	ROUND(yl, yr, 12);
91 	ROUND(yr, yl, 11);
92 	ROUND(yl, yr, 10);
93 	ROUND(yr, yl, 9);
94 	ROUND(yl, yr, 8);
95 	ROUND(yr, yl, 7);
96 	ROUND(yl, yr, 6);
97 	ROUND(yr, yl, 5);
98 	ROUND(yl, yr, 4);
99 	ROUND(yr, yl, 3);
100 	ROUND(yl, yr, 2);
101 
102 	yl ^= P[1];
103 	yr ^= P[0];
104 
105 	out_blk[0] = cpu_to_be32(yr);
106 	out_blk[1] = cpu_to_be32(yl);
107 }
108 
109 static struct crypto_alg alg = {
110 	.cra_name		=	"blowfish",
111 	.cra_driver_name	=	"blowfish-generic",
112 	.cra_priority		=	100,
113 	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
114 	.cra_blocksize		=	BF_BLOCK_SIZE,
115 	.cra_ctxsize		=	sizeof(struct bf_ctx),
116 	.cra_alignmask		=	3,
117 	.cra_module		=	THIS_MODULE,
118 	.cra_u			=	{ .cipher = {
119 	.cia_min_keysize	=	BF_MIN_KEY_SIZE,
120 	.cia_max_keysize	=	BF_MAX_KEY_SIZE,
121 	.cia_setkey		=	blowfish_setkey,
122 	.cia_encrypt		=	bf_encrypt,
123 	.cia_decrypt		=	bf_decrypt } }
124 };
125 
blowfish_mod_init(void)126 static int __init blowfish_mod_init(void)
127 {
128 	return crypto_register_alg(&alg);
129 }
130 
blowfish_mod_fini(void)131 static void __exit blowfish_mod_fini(void)
132 {
133 	crypto_unregister_alg(&alg);
134 }
135 
136 module_init(blowfish_mod_init);
137 module_exit(blowfish_mod_fini);
138 
139 MODULE_LICENSE("GPL");
140 MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
141 MODULE_ALIAS_CRYPTO("blowfish");
142 MODULE_ALIAS_CRYPTO("blowfish-generic");
143