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