crypto/blowfish_generic.c

   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
  36 static 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
  70 static 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
 104 static 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
 121 static int __init blowfish_mod_init(void)
 122 {
 123         return crypto_register_alg(&alg);
 124 }
 125
 126 static void __exit blowfish_mod_fini(void)
 127 {
 128         crypto_unregister_alg(&alg);
 129 }
 130
 131 subsys_initcall(blowfish_mod_init);
 132 module_exit(blowfish_mod_fini);
 133
 134 MODULE_LICENSE("GPL");
 135 MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
 136 MODULE_ALIAS_CRYPTO("blowfish");
 137 MODULE_ALIAS_CRYPTO("blowfish-generic");