crypto/blowfish_generic.c

   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
  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
  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
 126 static int __init blowfish_mod_init(void)
 127 {
 128         return crypto_register_alg(&alg);
 129 }
 130
 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("blowfish");