143 lines
3.4 KiB
C
143 lines
3.4 KiB
C
/*
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* Cryptographic API.
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*
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* Blowfish Cipher Algorithm, by Bruce Schneier.
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* http://www.counterpane.com/blowfish.html
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*
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* Adapted from Kerneli implementation.
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*
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* Copyright (c) Herbert Valerio Riedel <hvr@hvrlab.org>
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* Copyright (c) Kyle McMartin <kyle@debian.org>
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <asm/byteorder.h>
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#include <linux/crypto.h>
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#include <linux/types.h>
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#include <crypto/blowfish.h>
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/*
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* Round loop unrolling macros, S is a pointer to a S-Box array
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* organized in 4 unsigned longs at a row.
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*/
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#define GET32_3(x) (((x) & 0xff))
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#define GET32_2(x) (((x) >> (8)) & (0xff))
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#define GET32_1(x) (((x) >> (16)) & (0xff))
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#define GET32_0(x) (((x) >> (24)) & (0xff))
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#define bf_F(x) (((S[GET32_0(x)] + S[256 + GET32_1(x)]) ^ \
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S[512 + GET32_2(x)]) + S[768 + GET32_3(x)])
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#define ROUND(a, b, n) ({ b ^= P[n]; a ^= bf_F(b); })
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static void bf_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
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{
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struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
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const __be32 *in_blk = (const __be32 *)src;
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__be32 *const out_blk = (__be32 *)dst;
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const u32 *P = ctx->p;
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const u32 *S = ctx->s;
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u32 yl = be32_to_cpu(in_blk[0]);
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u32 yr = be32_to_cpu(in_blk[1]);
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ROUND(yr, yl, 0);
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ROUND(yl, yr, 1);
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ROUND(yr, yl, 2);
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ROUND(yl, yr, 3);
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ROUND(yr, yl, 4);
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ROUND(yl, yr, 5);
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ROUND(yr, yl, 6);
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ROUND(yl, yr, 7);
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ROUND(yr, yl, 8);
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ROUND(yl, yr, 9);
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ROUND(yr, yl, 10);
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ROUND(yl, yr, 11);
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ROUND(yr, yl, 12);
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ROUND(yl, yr, 13);
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ROUND(yr, yl, 14);
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ROUND(yl, yr, 15);
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yl ^= P[16];
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yr ^= P[17];
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out_blk[0] = cpu_to_be32(yr);
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out_blk[1] = cpu_to_be32(yl);
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}
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static void bf_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
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{
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struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
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const __be32 *in_blk = (const __be32 *)src;
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__be32 *const out_blk = (__be32 *)dst;
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const u32 *P = ctx->p;
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const u32 *S = ctx->s;
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u32 yl = be32_to_cpu(in_blk[0]);
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u32 yr = be32_to_cpu(in_blk[1]);
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ROUND(yr, yl, 17);
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ROUND(yl, yr, 16);
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ROUND(yr, yl, 15);
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ROUND(yl, yr, 14);
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ROUND(yr, yl, 13);
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ROUND(yl, yr, 12);
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ROUND(yr, yl, 11);
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ROUND(yl, yr, 10);
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ROUND(yr, yl, 9);
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ROUND(yl, yr, 8);
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ROUND(yr, yl, 7);
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ROUND(yl, yr, 6);
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ROUND(yr, yl, 5);
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ROUND(yl, yr, 4);
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ROUND(yr, yl, 3);
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ROUND(yl, yr, 2);
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yl ^= P[1];
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yr ^= P[0];
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out_blk[0] = cpu_to_be32(yr);
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out_blk[1] = cpu_to_be32(yl);
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}
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static struct crypto_alg alg = {
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.cra_name = "blowfish",
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.cra_driver_name = "blowfish-generic",
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.cra_priority = 100,
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.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
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.cra_blocksize = BF_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct bf_ctx),
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.cra_alignmask = 3,
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.cra_module = THIS_MODULE,
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.cra_list = LIST_HEAD_INIT(alg.cra_list),
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.cra_u = { .cipher = {
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.cia_min_keysize = BF_MIN_KEY_SIZE,
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.cia_max_keysize = BF_MAX_KEY_SIZE,
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.cia_setkey = blowfish_setkey,
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.cia_encrypt = bf_encrypt,
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.cia_decrypt = bf_decrypt } }
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};
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static int __init blowfish_mod_init(void)
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{
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return crypto_register_alg(&alg);
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}
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static void __exit blowfish_mod_fini(void)
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{
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crypto_unregister_alg(&alg);
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}
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module_init(blowfish_mod_init);
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module_exit(blowfish_mod_fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
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MODULE_ALIAS("blowfish");
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