337 lines
8.5 KiB
C
337 lines
8.5 KiB
C
/*
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* Cryptographic API.
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*
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* AES Cipher Algorithm.
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*
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* Based on Brian Gladman's code.
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*
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* Linux developers:
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* Alexander Kjeldaas <astor@fast.no>
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* Herbert Valerio Riedel <hvr@hvrlab.org>
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* Kyle McMartin <kyle@debian.org>
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* Adam J. Richter <adam@yggdrasil.com> (conversion to 2.5 API).
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* Andreas Steinmetz <ast@domdv.de> (adapted to x86_64 assembler)
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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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* Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
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* All rights reserved.
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*
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* LICENSE TERMS
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*
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* The free distribution and use of this software in both source and binary
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* form is allowed (with or without changes) provided that:
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*
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* 1. distributions of this source code include the above copyright
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* notice, this list of conditions and the following disclaimer;
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*
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* 2. distributions in binary form include the above copyright
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* notice, this list of conditions and the following disclaimer
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* in the documentation and/or other associated materials;
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*
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* 3. the copyright holder's name is not used to endorse products
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* built using this software without specific written permission.
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*
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* ALTERNATIVELY, provided that this notice is retained in full, this product
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* may be distributed under the terms of the GNU General Public License (GPL),
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* in which case the provisions of the GPL apply INSTEAD OF those given above.
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*
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* DISCLAIMER
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*
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* This software is provided 'as is' with no explicit or implied warranties
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* in respect of its properties, including, but not limited to, correctness
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* and/or fitness for purpose.
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* ---------------------------------------------------------------------------
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*/
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/* Some changes from the Gladman version:
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s/RIJNDAEL(e_key)/E_KEY/g
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s/RIJNDAEL(d_key)/D_KEY/g
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*/
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#include <asm/byteorder.h>
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#include <linux/bitops.h>
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#include <linux/crypto.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#define AES_MIN_KEY_SIZE 16
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#define AES_MAX_KEY_SIZE 32
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#define AES_BLOCK_SIZE 16
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/*
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* #define byte(x, nr) ((unsigned char)((x) >> (nr*8)))
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*/
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static inline u8 byte(const u32 x, const unsigned n)
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{
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return x >> (n << 3);
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}
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struct aes_ctx
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{
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u32 key_length;
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u32 buf[120];
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};
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#define E_KEY (&ctx->buf[0])
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#define D_KEY (&ctx->buf[60])
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static u8 pow_tab[256] __initdata;
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static u8 log_tab[256] __initdata;
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static u8 sbx_tab[256] __initdata;
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static u8 isb_tab[256] __initdata;
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static u32 rco_tab[10];
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u32 aes_ft_tab[4][256];
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u32 aes_it_tab[4][256];
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u32 aes_fl_tab[4][256];
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u32 aes_il_tab[4][256];
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static inline u8 f_mult(u8 a, u8 b)
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{
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u8 aa = log_tab[a], cc = aa + log_tab[b];
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return pow_tab[cc + (cc < aa ? 1 : 0)];
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}
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#define ff_mult(a, b) (a && b ? f_mult(a, b) : 0)
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#define ls_box(x) \
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(aes_fl_tab[0][byte(x, 0)] ^ \
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aes_fl_tab[1][byte(x, 1)] ^ \
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aes_fl_tab[2][byte(x, 2)] ^ \
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aes_fl_tab[3][byte(x, 3)])
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static void __init gen_tabs(void)
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{
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u32 i, t;
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u8 p, q;
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/* log and power tables for GF(2**8) finite field with
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0x011b as modular polynomial - the simplest primitive
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root is 0x03, used here to generate the tables */
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for (i = 0, p = 1; i < 256; ++i) {
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pow_tab[i] = (u8)p;
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log_tab[p] = (u8)i;
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p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
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}
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log_tab[1] = 0;
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for (i = 0, p = 1; i < 10; ++i) {
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rco_tab[i] = p;
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p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
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}
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for (i = 0; i < 256; ++i) {
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p = (i ? pow_tab[255 - log_tab[i]] : 0);
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q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
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p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
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sbx_tab[i] = p;
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isb_tab[p] = (u8)i;
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}
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for (i = 0; i < 256; ++i) {
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p = sbx_tab[i];
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t = p;
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aes_fl_tab[0][i] = t;
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aes_fl_tab[1][i] = rol32(t, 8);
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aes_fl_tab[2][i] = rol32(t, 16);
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aes_fl_tab[3][i] = rol32(t, 24);
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t = ((u32)ff_mult(2, p)) |
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((u32)p << 8) |
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((u32)p << 16) | ((u32)ff_mult(3, p) << 24);
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aes_ft_tab[0][i] = t;
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aes_ft_tab[1][i] = rol32(t, 8);
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aes_ft_tab[2][i] = rol32(t, 16);
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aes_ft_tab[3][i] = rol32(t, 24);
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p = isb_tab[i];
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t = p;
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aes_il_tab[0][i] = t;
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aes_il_tab[1][i] = rol32(t, 8);
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aes_il_tab[2][i] = rol32(t, 16);
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aes_il_tab[3][i] = rol32(t, 24);
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t = ((u32)ff_mult(14, p)) |
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((u32)ff_mult(9, p) << 8) |
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((u32)ff_mult(13, p) << 16) |
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((u32)ff_mult(11, p) << 24);
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aes_it_tab[0][i] = t;
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aes_it_tab[1][i] = rol32(t, 8);
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aes_it_tab[2][i] = rol32(t, 16);
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aes_it_tab[3][i] = rol32(t, 24);
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}
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}
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#define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
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#define imix_col(y, x) \
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u = star_x(x); \
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v = star_x(u); \
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w = star_x(v); \
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t = w ^ (x); \
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(y) = u ^ v ^ w; \
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(y) ^= ror32(u ^ t, 8) ^ \
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ror32(v ^ t, 16) ^ \
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ror32(t, 24)
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/* initialise the key schedule from the user supplied key */
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#define loop4(i) \
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{ \
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t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \
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t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \
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t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \
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t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \
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t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \
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}
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#define loop6(i) \
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{ \
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t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \
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t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \
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t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \
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t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \
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t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \
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t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \
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t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \
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}
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#define loop8(i) \
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{ \
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t = ror32(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \
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t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \
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t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \
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t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \
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t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \
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t = E_KEY[8 * i + 4] ^ ls_box(t); \
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E_KEY[8 * i + 12] = t; \
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t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \
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t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \
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t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \
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}
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static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
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unsigned int key_len)
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{
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struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
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const __le32 *key = (const __le32 *)in_key;
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u32 *flags = &tfm->crt_flags;
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u32 i, j, t, u, v, w;
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if (key_len % 8) {
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*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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}
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ctx->key_length = key_len;
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D_KEY[key_len + 24] = E_KEY[0] = le32_to_cpu(key[0]);
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D_KEY[key_len + 25] = E_KEY[1] = le32_to_cpu(key[1]);
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D_KEY[key_len + 26] = E_KEY[2] = le32_to_cpu(key[2]);
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D_KEY[key_len + 27] = E_KEY[3] = le32_to_cpu(key[3]);
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switch (key_len) {
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case 16:
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t = E_KEY[3];
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for (i = 0; i < 10; ++i)
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loop4(i);
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break;
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case 24:
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E_KEY[4] = le32_to_cpu(key[4]);
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t = E_KEY[5] = le32_to_cpu(key[5]);
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for (i = 0; i < 8; ++i)
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loop6 (i);
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break;
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case 32:
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E_KEY[4] = le32_to_cpu(key[4]);
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E_KEY[5] = le32_to_cpu(key[5]);
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E_KEY[6] = le32_to_cpu(key[6]);
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t = E_KEY[7] = le32_to_cpu(key[7]);
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for (i = 0; i < 7; ++i)
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loop8(i);
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break;
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}
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D_KEY[0] = E_KEY[key_len + 24];
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D_KEY[1] = E_KEY[key_len + 25];
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D_KEY[2] = E_KEY[key_len + 26];
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D_KEY[3] = E_KEY[key_len + 27];
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for (i = 4; i < key_len + 24; ++i) {
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j = key_len + 24 - (i & ~3) + (i & 3);
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imix_col(D_KEY[j], E_KEY[i]);
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}
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return 0;
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}
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asmlinkage void aes_enc_blk(struct crypto_tfm *tfm, u8 *out, const u8 *in);
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asmlinkage void aes_dec_blk(struct crypto_tfm *tfm, u8 *out, const u8 *in);
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static void aes_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
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{
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aes_enc_blk(tfm, dst, src);
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}
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static void aes_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
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{
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aes_dec_blk(tfm, dst, src);
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}
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static struct crypto_alg aes_alg = {
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.cra_name = "aes",
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.cra_driver_name = "aes-x86_64",
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.cra_priority = 200,
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.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
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.cra_blocksize = AES_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct aes_ctx),
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.cra_module = THIS_MODULE,
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.cra_list = LIST_HEAD_INIT(aes_alg.cra_list),
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.cra_u = {
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.cipher = {
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.cia_min_keysize = AES_MIN_KEY_SIZE,
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.cia_max_keysize = AES_MAX_KEY_SIZE,
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.cia_setkey = aes_set_key,
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.cia_encrypt = aes_encrypt,
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.cia_decrypt = aes_decrypt
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}
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}
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};
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static int __init aes_init(void)
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{
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gen_tabs();
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return crypto_register_alg(&aes_alg);
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}
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static void __exit aes_fini(void)
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{
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crypto_unregister_alg(&aes_alg);
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}
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module_init(aes_init);
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module_exit(aes_fini);
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MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("aes");
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