509 lines
14 KiB
C
509 lines
14 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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*
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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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#include <crypto/aes.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/crypto.h>
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#include <asm/byteorder.h>
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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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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 crypto_ft_tab[4][256];
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u32 crypto_fl_tab[4][256];
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u32 crypto_it_tab[4][256];
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u32 crypto_il_tab[4][256];
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EXPORT_SYMBOL_GPL(crypto_ft_tab);
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EXPORT_SYMBOL_GPL(crypto_fl_tab);
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EXPORT_SYMBOL_GPL(crypto_it_tab);
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EXPORT_SYMBOL_GPL(crypto_il_tab);
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static inline u8 __init 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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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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/*
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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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*/
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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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crypto_fl_tab[0][i] = t;
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crypto_fl_tab[1][i] = rol32(t, 8);
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crypto_fl_tab[2][i] = rol32(t, 16);
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crypto_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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crypto_ft_tab[0][i] = t;
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crypto_ft_tab[1][i] = rol32(t, 8);
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crypto_ft_tab[2][i] = rol32(t, 16);
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crypto_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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crypto_il_tab[0][i] = t;
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crypto_il_tab[1][i] = rol32(t, 8);
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crypto_il_tab[2][i] = rol32(t, 16);
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crypto_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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crypto_it_tab[0][i] = t;
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crypto_it_tab[1][i] = rol32(t, 8);
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crypto_it_tab[2][i] = rol32(t, 16);
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crypto_it_tab[3][i] = rol32(t, 24);
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}
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}
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/* initialise the key schedule from the user supplied key */
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#define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
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#define imix_col(y,x) do { \
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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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} while (0)
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#define ls_box(x) \
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crypto_fl_tab[0][byte(x, 0)] ^ \
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crypto_fl_tab[1][byte(x, 1)] ^ \
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crypto_fl_tab[2][byte(x, 2)] ^ \
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crypto_fl_tab[3][byte(x, 3)]
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#define loop4(i) do { \
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t = ror32(t, 8); \
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t = ls_box(t) ^ rco_tab[i]; \
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t ^= ctx->key_enc[4 * i]; \
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ctx->key_enc[4 * i + 4] = t; \
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t ^= ctx->key_enc[4 * i + 1]; \
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ctx->key_enc[4 * i + 5] = t; \
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t ^= ctx->key_enc[4 * i + 2]; \
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ctx->key_enc[4 * i + 6] = t; \
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t ^= ctx->key_enc[4 * i + 3]; \
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ctx->key_enc[4 * i + 7] = t; \
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} while (0)
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#define loop6(i) do { \
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t = ror32(t, 8); \
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t = ls_box(t) ^ rco_tab[i]; \
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t ^= ctx->key_enc[6 * i]; \
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ctx->key_enc[6 * i + 6] = t; \
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t ^= ctx->key_enc[6 * i + 1]; \
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ctx->key_enc[6 * i + 7] = t; \
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t ^= ctx->key_enc[6 * i + 2]; \
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ctx->key_enc[6 * i + 8] = t; \
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t ^= ctx->key_enc[6 * i + 3]; \
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ctx->key_enc[6 * i + 9] = t; \
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t ^= ctx->key_enc[6 * i + 4]; \
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ctx->key_enc[6 * i + 10] = t; \
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t ^= ctx->key_enc[6 * i + 5]; \
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ctx->key_enc[6 * i + 11] = t; \
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} while (0)
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#define loop8(i) do { \
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t = ror32(t, 8); \
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t = ls_box(t) ^ rco_tab[i]; \
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t ^= ctx->key_enc[8 * i]; \
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ctx->key_enc[8 * i + 8] = t; \
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t ^= ctx->key_enc[8 * i + 1]; \
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ctx->key_enc[8 * i + 9] = t; \
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t ^= ctx->key_enc[8 * i + 2]; \
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ctx->key_enc[8 * i + 10] = t; \
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t ^= ctx->key_enc[8 * i + 3]; \
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ctx->key_enc[8 * i + 11] = t; \
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t = ctx->key_enc[8 * i + 4] ^ ls_box(t); \
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ctx->key_enc[8 * i + 12] = t; \
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t ^= ctx->key_enc[8 * i + 5]; \
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ctx->key_enc[8 * i + 13] = t; \
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t ^= ctx->key_enc[8 * i + 6]; \
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ctx->key_enc[8 * i + 14] = t; \
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t ^= ctx->key_enc[8 * i + 7]; \
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ctx->key_enc[8 * i + 15] = t; \
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} while (0)
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/**
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* crypto_aes_expand_key - Expands the AES key as described in FIPS-197
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* @ctx: The location where the computed key will be stored.
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* @in_key: The supplied key.
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* @key_len: The length of the supplied key.
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*
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* Returns 0 on success. The function fails only if an invalid key size (or
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* pointer) is supplied.
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* The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
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* key schedule plus a 16 bytes key which is used before the first round).
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* The decryption key is prepared for the "Equivalent Inverse Cipher" as
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* described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
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* for the initial combination, the second slot for the first round and so on.
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*/
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int crypto_aes_expand_key(struct crypto_aes_ctx *ctx, const u8 *in_key,
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unsigned int key_len)
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{
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const __le32 *key = (const __le32 *)in_key;
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u32 i, t, u, v, w, j;
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if (key_len != AES_KEYSIZE_128 && key_len != AES_KEYSIZE_192 &&
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key_len != AES_KEYSIZE_256)
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return -EINVAL;
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ctx->key_length = key_len;
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ctx->key_dec[key_len + 24] = ctx->key_enc[0] = le32_to_cpu(key[0]);
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ctx->key_dec[key_len + 25] = ctx->key_enc[1] = le32_to_cpu(key[1]);
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ctx->key_dec[key_len + 26] = ctx->key_enc[2] = le32_to_cpu(key[2]);
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ctx->key_dec[key_len + 27] = ctx->key_enc[3] = le32_to_cpu(key[3]);
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switch (key_len) {
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case AES_KEYSIZE_128:
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t = ctx->key_enc[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 AES_KEYSIZE_192:
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ctx->key_enc[4] = le32_to_cpu(key[4]);
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t = ctx->key_enc[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 AES_KEYSIZE_256:
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ctx->key_enc[4] = le32_to_cpu(key[4]);
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ctx->key_enc[5] = le32_to_cpu(key[5]);
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ctx->key_enc[6] = le32_to_cpu(key[6]);
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t = ctx->key_enc[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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ctx->key_dec[0] = ctx->key_enc[key_len + 24];
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ctx->key_dec[1] = ctx->key_enc[key_len + 25];
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ctx->key_dec[2] = ctx->key_enc[key_len + 26];
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ctx->key_dec[3] = ctx->key_enc[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(ctx->key_dec[j], ctx->key_enc[i]);
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(crypto_aes_expand_key);
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/**
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* crypto_aes_set_key - Set the AES key.
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* @tfm: The %crypto_tfm that is used in the context.
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* @in_key: The input key.
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* @key_len: The size of the key.
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*
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* Returns 0 on success, on failure the %CRYPTO_TFM_RES_BAD_KEY_LEN flag in tfm
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* is set. The function uses crypto_aes_expand_key() to expand the key.
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* &crypto_aes_ctx _must_ be the private data embedded in @tfm which is
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* retrieved with crypto_tfm_ctx().
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*/
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int crypto_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 crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
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u32 *flags = &tfm->crt_flags;
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int ret;
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ret = crypto_aes_expand_key(ctx, in_key, key_len);
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if (!ret)
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return 0;
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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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EXPORT_SYMBOL_GPL(crypto_aes_set_key);
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/* encrypt a block of text */
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#define f_rn(bo, bi, n, k) do { \
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bo[n] = crypto_ft_tab[0][byte(bi[n], 0)] ^ \
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crypto_ft_tab[1][byte(bi[(n + 1) & 3], 1)] ^ \
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crypto_ft_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \
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crypto_ft_tab[3][byte(bi[(n + 3) & 3], 3)] ^ *(k + n); \
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} while (0)
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#define f_nround(bo, bi, k) do {\
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f_rn(bo, bi, 0, k); \
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f_rn(bo, bi, 1, k); \
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f_rn(bo, bi, 2, k); \
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f_rn(bo, bi, 3, k); \
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k += 4; \
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} while (0)
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#define f_rl(bo, bi, n, k) do { \
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bo[n] = crypto_fl_tab[0][byte(bi[n], 0)] ^ \
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crypto_fl_tab[1][byte(bi[(n + 1) & 3], 1)] ^ \
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crypto_fl_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \
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crypto_fl_tab[3][byte(bi[(n + 3) & 3], 3)] ^ *(k + n); \
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} while (0)
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#define f_lround(bo, bi, k) do {\
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f_rl(bo, bi, 0, k); \
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f_rl(bo, bi, 1, k); \
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f_rl(bo, bi, 2, k); \
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f_rl(bo, bi, 3, k); \
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} while (0)
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static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
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{
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const struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
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const __le32 *src = (const __le32 *)in;
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__le32 *dst = (__le32 *)out;
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u32 b0[4], b1[4];
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const u32 *kp = ctx->key_enc + 4;
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const int key_len = ctx->key_length;
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b0[0] = le32_to_cpu(src[0]) ^ ctx->key_enc[0];
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b0[1] = le32_to_cpu(src[1]) ^ ctx->key_enc[1];
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b0[2] = le32_to_cpu(src[2]) ^ ctx->key_enc[2];
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b0[3] = le32_to_cpu(src[3]) ^ ctx->key_enc[3];
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if (key_len > 24) {
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f_nround(b1, b0, kp);
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f_nround(b0, b1, kp);
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}
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if (key_len > 16) {
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f_nround(b1, b0, kp);
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f_nround(b0, b1, kp);
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}
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f_nround(b1, b0, kp);
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f_nround(b0, b1, kp);
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f_nround(b1, b0, kp);
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f_nround(b0, b1, kp);
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f_nround(b1, b0, kp);
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f_nround(b0, b1, kp);
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f_nround(b1, b0, kp);
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f_nround(b0, b1, kp);
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f_nround(b1, b0, kp);
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f_lround(b0, b1, kp);
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dst[0] = cpu_to_le32(b0[0]);
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dst[1] = cpu_to_le32(b0[1]);
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dst[2] = cpu_to_le32(b0[2]);
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dst[3] = cpu_to_le32(b0[3]);
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}
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/* decrypt a block of text */
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#define i_rn(bo, bi, n, k) do { \
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bo[n] = crypto_it_tab[0][byte(bi[n], 0)] ^ \
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crypto_it_tab[1][byte(bi[(n + 3) & 3], 1)] ^ \
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crypto_it_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \
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crypto_it_tab[3][byte(bi[(n + 1) & 3], 3)] ^ *(k + n); \
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} while (0)
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#define i_nround(bo, bi, k) do {\
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i_rn(bo, bi, 0, k); \
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i_rn(bo, bi, 1, k); \
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i_rn(bo, bi, 2, k); \
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i_rn(bo, bi, 3, k); \
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k += 4; \
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} while (0)
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#define i_rl(bo, bi, n, k) do { \
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bo[n] = crypto_il_tab[0][byte(bi[n], 0)] ^ \
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crypto_il_tab[1][byte(bi[(n + 3) & 3], 1)] ^ \
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crypto_il_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \
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crypto_il_tab[3][byte(bi[(n + 1) & 3], 3)] ^ *(k + n); \
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} while (0)
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#define i_lround(bo, bi, k) do {\
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i_rl(bo, bi, 0, k); \
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i_rl(bo, bi, 1, k); \
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i_rl(bo, bi, 2, k); \
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i_rl(bo, bi, 3, k); \
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} while (0)
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static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
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{
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const struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
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const __le32 *src = (const __le32 *)in;
|
|
__le32 *dst = (__le32 *)out;
|
|
u32 b0[4], b1[4];
|
|
const int key_len = ctx->key_length;
|
|
const u32 *kp = ctx->key_dec + 4;
|
|
|
|
b0[0] = le32_to_cpu(src[0]) ^ ctx->key_dec[0];
|
|
b0[1] = le32_to_cpu(src[1]) ^ ctx->key_dec[1];
|
|
b0[2] = le32_to_cpu(src[2]) ^ ctx->key_dec[2];
|
|
b0[3] = le32_to_cpu(src[3]) ^ ctx->key_dec[3];
|
|
|
|
if (key_len > 24) {
|
|
i_nround(b1, b0, kp);
|
|
i_nround(b0, b1, kp);
|
|
}
|
|
|
|
if (key_len > 16) {
|
|
i_nround(b1, b0, kp);
|
|
i_nround(b0, b1, kp);
|
|
}
|
|
|
|
i_nround(b1, b0, kp);
|
|
i_nround(b0, b1, kp);
|
|
i_nround(b1, b0, kp);
|
|
i_nround(b0, b1, kp);
|
|
i_nround(b1, b0, kp);
|
|
i_nround(b0, b1, kp);
|
|
i_nround(b1, b0, kp);
|
|
i_nround(b0, b1, kp);
|
|
i_nround(b1, b0, kp);
|
|
i_lround(b0, b1, kp);
|
|
|
|
dst[0] = cpu_to_le32(b0[0]);
|
|
dst[1] = cpu_to_le32(b0[1]);
|
|
dst[2] = cpu_to_le32(b0[2]);
|
|
dst[3] = cpu_to_le32(b0[3]);
|
|
}
|
|
|
|
static struct crypto_alg aes_alg = {
|
|
.cra_name = "aes",
|
|
.cra_driver_name = "aes-generic",
|
|
.cra_priority = 100,
|
|
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
|
|
.cra_blocksize = AES_BLOCK_SIZE,
|
|
.cra_ctxsize = sizeof(struct crypto_aes_ctx),
|
|
.cra_alignmask = 3,
|
|
.cra_module = THIS_MODULE,
|
|
.cra_list = LIST_HEAD_INIT(aes_alg.cra_list),
|
|
.cra_u = {
|
|
.cipher = {
|
|
.cia_min_keysize = AES_MIN_KEY_SIZE,
|
|
.cia_max_keysize = AES_MAX_KEY_SIZE,
|
|
.cia_setkey = crypto_aes_set_key,
|
|
.cia_encrypt = aes_encrypt,
|
|
.cia_decrypt = aes_decrypt
|
|
}
|
|
}
|
|
};
|
|
|
|
static int __init aes_init(void)
|
|
{
|
|
gen_tabs();
|
|
return crypto_register_alg(&aes_alg);
|
|
}
|
|
|
|
static void __exit aes_fini(void)
|
|
{
|
|
crypto_unregister_alg(&aes_alg);
|
|
}
|
|
|
|
module_init(aes_init);
|
|
module_exit(aes_fini);
|
|
|
|
MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
|
|
MODULE_LICENSE("Dual BSD/GPL");
|
|
MODULE_ALIAS("aes");
|