/* * 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). * * 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 <linux/module.h> #include <linux/init.h> #include <linux/types.h> #include <linux/errno.h> #include <linux/crypto.h> #include <asm/byteorder.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 u32 *)(x)) #define u32_out(to, from) (*(u32 *)(to) = cpu_to_le32(from)) struct aes_ctx { int 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]; static u32 ft_tab[4][256]; static u32 it_tab[4][256]; static u32 fl_tab[4][256]; static u32 il_tab[4][256]; static inline u8 __init 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 f_rn(bo, bi, n, k) \ bo[n] = ft_tab[0][byte(bi[n],0)] ^ \ ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) #define i_rn(bo, bi, n, k) \ bo[n] = it_tab[0][byte(bi[n],0)] ^ \ it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) #define ls_box(x) \ ( fl_tab[0][byte(x, 0)] ^ \ fl_tab[1][byte(x, 1)] ^ \ fl_tab[2][byte(x, 2)] ^ \ fl_tab[3][byte(x, 3)] ) #define f_rl(bo, bi, n, k) \ bo[n] = fl_tab[0][byte(bi[n],0)] ^ \ fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) #define i_rl(bo, bi, n, k) \ bo[n] = il_tab[0][byte(bi[n],0)] ^ \ il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) 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; fl_tab[0][i] = t; fl_tab[1][i] = rol32(t, 8); fl_tab[2][i] = rol32(t, 16); 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); ft_tab[0][i] = t; ft_tab[1][i] = rol32(t, 8); ft_tab[2][i] = rol32(t, 16); ft_tab[3][i] = rol32(t, 24); p = isb_tab[i]; t = p; il_tab[0][i] = t; il_tab[1][i] = rol32(t, 8); il_tab[2][i] = rol32(t, 16); 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); it_tab[0][i] = t; it_tab[1][i] = rol32(t, 8); it_tab[2][i] = rol32(t, 16); 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, 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; E_KEY[0] = u32_in (in_key); E_KEY[1] = u32_in (in_key + 4); E_KEY[2] = u32_in (in_key + 8); 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[0]; D_KEY[1] = E_KEY[1]; D_KEY[2] = E_KEY[2]; D_KEY[3] = E_KEY[3]; for (i = 4; i < key_len + 24; ++i) { imix_col (D_KEY[i], E_KEY[i]); } return 0; } /* encrypt a block of text */ #define f_nround(bo, bi, k) \ f_rn(bo, bi, 0, k); \ f_rn(bo, bi, 1, k); \ f_rn(bo, bi, 2, k); \ f_rn(bo, bi, 3, k); \ k += 4 #define f_lround(bo, bi, k) \ f_rl(bo, bi, 0, k); \ f_rl(bo, bi, 1, k); \ f_rl(bo, bi, 2, k); \ f_rl(bo, bi, 3, k) static void aes_encrypt(void *ctx_arg, u8 *out, const u8 *in) { const struct aes_ctx *ctx = ctx_arg; u32 b0[4], b1[4]; const u32 *kp = E_KEY + 4; b0[0] = u32_in (in) ^ E_KEY[0]; b0[1] = u32_in (in + 4) ^ E_KEY[1]; b0[2] = u32_in (in + 8) ^ E_KEY[2]; b0[3] = u32_in (in + 12) ^ E_KEY[3]; if (ctx->key_length > 24) { f_nround (b1, b0, kp); f_nround (b0, b1, kp); } if (ctx->key_length > 16) { f_nround (b1, b0, kp); f_nround (b0, b1, kp); } f_nround (b1, b0, kp); f_nround (b0, b1, kp); f_nround (b1, b0, kp); f_nround (b0, b1, kp); f_nround (b1, b0, kp); f_nround (b0, b1, kp); f_nround (b1, b0, kp); f_nround (b0, b1, kp); f_nround (b1, b0, kp); f_lround (b0, b1, kp); u32_out (out, b0[0]); u32_out (out + 4, b0[1]); u32_out (out + 8, b0[2]); u32_out (out + 12, b0[3]); } /* decrypt a block of text */ #define i_nround(bo, bi, k) \ i_rn(bo, bi, 0, k); \ i_rn(bo, bi, 1, k); \ i_rn(bo, bi, 2, k); \ i_rn(bo, bi, 3, k); \ k -= 4 #define i_lround(bo, bi, k) \ i_rl(bo, bi, 0, k); \ i_rl(bo, bi, 1, k); \ i_rl(bo, bi, 2, k); \ i_rl(bo, bi, 3, k) static void aes_decrypt(void *ctx_arg, u8 *out, const u8 *in) { const struct aes_ctx *ctx = ctx_arg; u32 b0[4], b1[4]; const int key_len = ctx->key_length; const u32 *kp = D_KEY + key_len + 20; b0[0] = u32_in (in) ^ E_KEY[key_len + 24]; b0[1] = u32_in (in + 4) ^ E_KEY[key_len + 25]; b0[2] = u32_in (in + 8) ^ E_KEY[key_len + 26]; b0[3] = u32_in (in + 12) ^ E_KEY[key_len + 27]; 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); u32_out (out, b0[0]); u32_out (out + 4, b0[1]); u32_out (out + 8, b0[2]); u32_out (out + 12, b0[3]); } 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("Dual BSD/GPL");