LXR linux/crypto/blowfish

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