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/unaligned.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 u32 *P = ctx->p;
  40         const u32 *S = ctx->s;
  41         u32 yl = get_unaligned_be32(src);
  42         u32 yr = get_unaligned_be32(src + 4);
  43
  44         ROUND(yr, yl, 0);
  45         ROUND(yl, yr, 1);
  46         ROUND(yr, yl, 2);
  47         ROUND(yl, yr, 3);
  48         ROUND(yr, yl, 4);
  49         ROUND(yl, yr, 5);
  50         ROUND(yr, yl, 6);
  51         ROUND(yl, yr, 7);
  52         ROUND(yr, yl, 8);
  53         ROUND(yl, yr, 9);
  54         ROUND(yr, yl, 10);
  55         ROUND(yl, yr, 11);
  56         ROUND(yr, yl, 12);
  57         ROUND(yl, yr, 13);
  58         ROUND(yr, yl, 14);
  59         ROUND(yl, yr, 15);
  60
  61         yl ^= P[16];
  62         yr ^= P[17];
  63
  64         put_unaligned_be32(yr, dst);
  65         put_unaligned_be32(yl, dst + 4);
  66 }
  67
  68 static void bf_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  69 {
  70         struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
  71         const u32 *P = ctx->p;
  72         const u32 *S = ctx->s;
  73         u32 yl = get_unaligned_be32(src);
  74         u32 yr = get_unaligned_be32(src + 4);
  75
  76         ROUND(yr, yl, 17);
  77         ROUND(yl, yr, 16);
  78         ROUND(yr, yl, 15);
  79         ROUND(yl, yr, 14);
  80         ROUND(yr, yl, 13);
  81         ROUND(yl, yr, 12);
  82         ROUND(yr, yl, 11);
  83         ROUND(yl, yr, 10);
  84         ROUND(yr, yl, 9);
  85         ROUND(yl, yr, 8);
  86         ROUND(yr, yl, 7);
  87         ROUND(yl, yr, 6);
  88         ROUND(yr, yl, 5);
  89         ROUND(yl, yr, 4);
  90         ROUND(yr, yl, 3);
  91         ROUND(yl, yr, 2);
  92
  93         yl ^= P[1];
  94         yr ^= P[0];
  95
  96         put_unaligned_be32(yr, dst);
  97         put_unaligned_be32(yl, dst + 4);
  98 }
  99
 100 static struct crypto_alg alg = {
 101         .cra_name               =       "blowfish",
 102         .cra_driver_name        =       "blowfish-generic",
 103         .cra_priority           =       100,
 104         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 105         .cra_blocksize          =       BF_BLOCK_SIZE,
 106         .cra_ctxsize            =       sizeof(struct bf_ctx),
 107         .cra_module             =       THIS_MODULE,
 108         .cra_u                  =       { .cipher = {
 109         .cia_min_keysize        =       BF_MIN_KEY_SIZE,
 110         .cia_max_keysize        =       BF_MAX_KEY_SIZE,
 111         .cia_setkey             =       blowfish_setkey,
 112         .cia_encrypt            =       bf_encrypt,
 113         .cia_decrypt            =       bf_decrypt } }
 114 };
 115
 116 static int __init blowfish_mod_init(void)
 117 {
 118         return crypto_register_alg(&alg);
 119 }
 120
 121 static void __exit blowfish_mod_fini(void)
 122 {
 123         crypto_unregister_alg(&alg);
 124 }
 125
 126 subsys_initcall(blowfish_mod_init);
 127 module_exit(blowfish_mod_fini);
 128
 129 MODULE_LICENSE("GPL");
 130 MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
 131 MODULE_ALIAS_CRYPTO("blowfish");
 132 MODULE_ALIAS_CRYPTO("blowfish-generic");