linux/crypto/blowfish_generic.c
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   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
  36static 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
  68static 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
 100static 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
 116static int __init blowfish_mod_init(void)
 117{
 118        return crypto_register_alg(&alg);
 119}
 120
 121static void __exit blowfish_mod_fini(void)
 122{
 123        crypto_unregister_alg(&alg);
 124}
 125
 126subsys_initcall(blowfish_mod_init);
 127module_exit(blowfish_mod_fini);
 128
 129MODULE_LICENSE("GPL");
 130MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
 131MODULE_ALIAS_CRYPTO("blowfish");
 132MODULE_ALIAS_CRYPTO("blowfish-generic");
 133
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