/* * Cryptographic API. * * AES Cipher Algorithm. * * Based on Brian Gladman's code. * * Linux developers: * Alexander Kjeldaas <astor@fast.no> * Herbert Valerio Riedel <hvr@hvrlab.org> * Kyle McMartin <kyle@debian.org> * Adam J. Richter <adam@yggdrasil.com> (conversion to 2.5 API). * Andreas Steinmetz <ast@domdv.de> (adapted to x86_64 assembler) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * --------------------------------------------------------------------------- * Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK. * All rights reserved. * * LICENSE TERMS * * The free distribution and use of this software in both source and binary * form is allowed (with or without changes) provided that: * * 1. distributions of this source code include the above copyright * notice, this list of conditions and the following disclaimer; * * 2. distributions in binary form include the above copyright * notice, this list of conditions and the following disclaimer * in the documentation and/or other associated materials; * * 3. the copyright holder's name is not used to endorse products * built using this software without specific written permission. * * ALTERNATIVELY, provided that this notice is retained in full, this product * may be distributed under the terms of the GNU General Public License (GPL), * in which case the provisions of the GPL apply INSTEAD OF those given above. * * DISCLAIMER * * This software is provided 'as is' with no explicit or implied warranties * in respect of its properties, including, but not limited to, correctness * and/or fitness for purpose. * --------------------------------------------------------------------------- */ /* Some changes from the Gladman version: s/RIJNDAEL(e_key)/E_KEY/g s/RIJNDAEL(d_key)/D_KEY/g */ #include <asm/byteorder.h> #include <linux/bitops.h> #include <linux/crypto.h> #include <linux/errno.h> #include <linux/init.h> #include <linux/module.h> #include <linux/types.h> #define AES_MIN_KEY_SIZE 16 #define AES_MAX_KEY_SIZE 32 #define AES_BLOCK_SIZE 16 /* * #define byte(x, nr) ((unsigned char)((x) >> (nr*8))) */ static inline u8 byte(const u32 x, const unsigned n) { return x >> (n << 3); } #define u32_in(x) le32_to_cpu(*(const __le32 *)(x)) struct aes_ctx { u32 key_length; u32 E[60]; u32 D[60]; }; #define E_KEY ctx->E #define D_KEY ctx->D static u8 pow_tab[256] __initdata; static u8 log_tab[256] __initdata; static u8 sbx_tab[256] __initdata; static u8 isb_tab[256] __initdata; static u32 rco_tab[10]; u32 aes_ft_tab[4][256]; u32 aes_it_tab[4][256]; u32 aes_fl_tab[4][256]; u32 aes_il_tab[4][256]; static inline u8 f_mult(u8 a, u8 b) { u8 aa = log_tab[a], cc = aa + log_tab[b]; return pow_tab[cc + (cc < aa ? 1 : 0)]; } #define ff_mult(a, b) (a && b ? f_mult(a, b) : 0) #define ls_box(x) \ (aes_fl_tab[0][byte(x, 0)] ^ \ aes_fl_tab[1][byte(x, 1)] ^ \ aes_fl_tab[2][byte(x, 2)] ^ \ aes_fl_tab[3][byte(x, 3)]) static void __init gen_tabs(void) { u32 i, t; u8 p, q; /* log and power tables for GF(2**8) finite field with 0x011b as modular polynomial - the simplest primitive root is 0x03, used here to generate the tables */ for (i = 0, p = 1; i < 256; ++i) { pow_tab[i] = (u8)p; log_tab[p] = (u8)i; p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0); } log_tab[1] = 0; for (i = 0, p = 1; i < 10; ++i) { rco_tab[i] = p; p = (p << 1) ^ (p & 0x80 ? 0x01b : 0); } for (i = 0; i < 256; ++i) { p = (i ? pow_tab[255 - log_tab[i]] : 0); q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2)); p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2)); sbx_tab[i] = p; isb_tab[p] = (u8)i; } for (i = 0; i < 256; ++i) { p = sbx_tab[i]; t = p; aes_fl_tab[0][i] = t; aes_fl_tab[1][i] = rol32(t, 8); aes_fl_tab[2][i] = rol32(t, 16); aes_fl_tab[3][i] = rol32(t, 24); t = ((u32)ff_mult(2, p)) | ((u32)p << 8) | ((u32)p << 16) | ((u32)ff_mult(3, p) << 24); aes_ft_tab[0][i] = t; aes_ft_tab[1][i] = rol32(t, 8); aes_ft_tab[2][i] = rol32(t, 16); aes_ft_tab[3][i] = rol32(t, 24); p = isb_tab[i]; t = p; aes_il_tab[0][i] = t; aes_il_tab[1][i] = rol32(t, 8); aes_il_tab[2][i] = rol32(t, 16); aes_il_tab[3][i] = rol32(t, 24); t = ((u32)ff_mult(14, p)) | ((u32)ff_mult(9, p) << 8) | ((u32)ff_mult(13, p) << 16) | ((u32)ff_mult(11, p) << 24); aes_it_tab[0][i] = t; aes_it_tab[1][i] = rol32(t, 8); aes_it_tab[2][i] = rol32(t, 16); aes_it_tab[3][i] = rol32(t, 24); } } #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b) #define imix_col(y, x) \ u = star_x(x); \ v = star_x(u); \ w = star_x(v); \ t = w ^ (x); \ (y) = u ^ v ^ w; \ (y) ^= ror32(u ^ t, 8) ^ \ ror32(v ^ t, 16) ^ \ ror32(t, 24) /* initialise the key schedule from the user supplied key */ #define loop4(i) \ { \ t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \ t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \ t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \ t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \ t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \ } #define loop6(i) \ { \ t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \ t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \ t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \ t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \ t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \ t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \ t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \ } #define loop8(i) \ { \ t = ror32(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \ t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \ t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \ t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \ t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \ t = E_KEY[8 * i + 4] ^ ls_box(t); \ E_KEY[8 * i + 12] = t; \ t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \ t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \ t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \ } static int aes_set_key(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags) { struct aes_ctx *ctx = ctx_arg; u32 i, j, t, u, v, w; if (key_len != 16 && key_len != 24 && key_len != 32) { *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; return -EINVAL; } ctx->key_length = key_len; D_KEY[key_len + 24] = E_KEY[0] = u32_in(in_key); D_KEY[key_len + 25] = E_KEY[1] = u32_in(in_key + 4); D_KEY[key_len + 26] = E_KEY[2] = u32_in(in_key + 8); D_KEY[key_len + 27] = E_KEY[3] = u32_in(in_key + 12); switch (key_len) { case 16: t = E_KEY[3]; for (i = 0; i < 10; ++i) loop4(i); break; case 24: E_KEY[4] = u32_in(in_key + 16); t = E_KEY[5] = u32_in(in_key + 20); for (i = 0; i < 8; ++i) loop6 (i); break; case 32: E_KEY[4] = u32_in(in_key + 16); E_KEY[5] = u32_in(in_key + 20); E_KEY[6] = u32_in(in_key + 24); t = E_KEY[7] = u32_in(in_key + 28); for (i = 0; i < 7; ++i) loop8(i); break; } D_KEY[0] = E_KEY[key_len + 24]; D_KEY[1] = E_KEY[key_len + 25]; D_KEY[2] = E_KEY[key_len + 26]; D_KEY[3] = E_KEY[key_len + 27]; for (i = 4; i < key_len + 24; ++i) { j = key_len + 24 - (i & ~3) + (i & 3); imix_col(D_KEY[j], E_KEY[i]); } return 0; } extern void aes_encrypt(void *ctx_arg, u8 *out, const u8 *in); extern void aes_decrypt(void *ctx_arg, u8 *out, const u8 *in); static struct crypto_alg aes_alg = { .cra_name = "aes", .cra_flags = CRYPTO_ALG_TYPE_CIPHER, .cra_blocksize = AES_BLOCK_SIZE, .cra_ctxsize = sizeof(struct aes_ctx), .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 = 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("GPL"); MODULE_ALIAS("aes");