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+/*
+ * 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)))
+ */
+inline static 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");
+
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