mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-13 23:02:59 +00:00
231 lines
6.4 KiB
C
231 lines
6.4 KiB
C
|
/*
|
||
|
* Copyright (c) 2011 The Chromium OS Authors.
|
||
|
* (C) Copyright 2010 - 2011 NVIDIA Corporation <www.nvidia.com>
|
||
|
*
|
||
|
* See file CREDITS for list of people who contributed to this
|
||
|
* project.
|
||
|
*
|
||
|
* 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.
|
||
|
*
|
||
|
* This program is distributed in the hope that it will be useful,
|
||
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
* GNU General Public License for more details.
|
||
|
*
|
||
|
* You should have received a copy of the GNU General Public License
|
||
|
* along with this program; if not, write to the Free Software
|
||
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
|
||
|
* MA 02111-1307 USA
|
||
|
*/
|
||
|
|
||
|
#include <common.h>
|
||
|
#include <asm/errno.h>
|
||
|
#include "crypto.h"
|
||
|
#include "aes.h"
|
||
|
|
||
|
static u8 zero_key[16];
|
||
|
|
||
|
#define AES_CMAC_CONST_RB 0x87 /* from RFC 4493, Figure 2.2 */
|
||
|
|
||
|
enum security_op {
|
||
|
SECURITY_SIGN = 1 << 0, /* Sign the data */
|
||
|
SECURITY_ENCRYPT = 1 << 1, /* Encrypt the data */
|
||
|
};
|
||
|
|
||
|
static void debug_print_vector(char *name, u32 num_bytes, u8 *data)
|
||
|
{
|
||
|
u32 i;
|
||
|
|
||
|
debug("%s [%d] @0x%08x", name, num_bytes, (u32)data);
|
||
|
for (i = 0; i < num_bytes; i++) {
|
||
|
if (i % 16 == 0)
|
||
|
debug(" = ");
|
||
|
debug("%02x", data[i]);
|
||
|
if ((i+1) % 16 != 0)
|
||
|
debug(" ");
|
||
|
}
|
||
|
debug("\n");
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Apply chain data to the destination using EOR
|
||
|
*
|
||
|
* Each array is of length AES_AES_KEY_LENGTH.
|
||
|
*
|
||
|
* \param cbc_chain_data Chain data
|
||
|
* \param src Source data
|
||
|
* \param dst Destination data, which is modified here
|
||
|
*/
|
||
|
static void apply_cbc_chain_data(u8 *cbc_chain_data, u8 *src, u8 *dst)
|
||
|
{
|
||
|
int i;
|
||
|
|
||
|
for (i = 0; i < 16; i++)
|
||
|
*dst++ = *src++ ^ *cbc_chain_data++;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Encrypt some data with AES.
|
||
|
*
|
||
|
* \param key_schedule Expanded key to use
|
||
|
* \param src Source data to encrypt
|
||
|
* \param dst Destination buffer
|
||
|
* \param num_aes_blocks Number of AES blocks to encrypt
|
||
|
*/
|
||
|
static void encrypt_object(u8 *key_schedule, u8 *src, u8 *dst,
|
||
|
u32 num_aes_blocks)
|
||
|
{
|
||
|
u8 tmp_data[AES_KEY_LENGTH];
|
||
|
u8 *cbc_chain_data;
|
||
|
u32 i;
|
||
|
|
||
|
cbc_chain_data = zero_key; /* Convenient array of 0's for IV */
|
||
|
|
||
|
for (i = 0; i < num_aes_blocks; i++) {
|
||
|
debug("encrypt_object: block %d of %d\n", i, num_aes_blocks);
|
||
|
debug_print_vector("AES Src", AES_KEY_LENGTH, src);
|
||
|
|
||
|
/* Apply the chain data */
|
||
|
apply_cbc_chain_data(cbc_chain_data, src, tmp_data);
|
||
|
debug_print_vector("AES Xor", AES_KEY_LENGTH, tmp_data);
|
||
|
|
||
|
/* encrypt the AES block */
|
||
|
aes_encrypt(tmp_data, key_schedule, dst);
|
||
|
debug_print_vector("AES Dst", AES_KEY_LENGTH, dst);
|
||
|
|
||
|
/* Update pointers for next loop. */
|
||
|
cbc_chain_data = dst;
|
||
|
src += AES_KEY_LENGTH;
|
||
|
dst += AES_KEY_LENGTH;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Shift a vector left by one bit
|
||
|
*
|
||
|
* \param in Input vector
|
||
|
* \param out Output vector
|
||
|
* \param size Length of vector in bytes
|
||
|
*/
|
||
|
static void left_shift_vector(u8 *in, u8 *out, int size)
|
||
|
{
|
||
|
int carry = 0;
|
||
|
int i;
|
||
|
|
||
|
for (i = size - 1; i >= 0; i--) {
|
||
|
out[i] = (in[i] << 1) | carry;
|
||
|
carry = in[i] >> 7; /* get most significant bit */
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Sign a block of data, putting the result into dst.
|
||
|
*
|
||
|
* \param key Input AES key, length AES_KEY_LENGTH
|
||
|
* \param key_schedule Expanded key to use
|
||
|
* \param src Source data of length 'num_aes_blocks' blocks
|
||
|
* \param dst Destination buffer, length AES_KEY_LENGTH
|
||
|
* \param num_aes_blocks Number of AES blocks to encrypt
|
||
|
*/
|
||
|
static void sign_object(u8 *key, u8 *key_schedule, u8 *src, u8 *dst,
|
||
|
u32 num_aes_blocks)
|
||
|
{
|
||
|
u8 tmp_data[AES_KEY_LENGTH];
|
||
|
u8 left[AES_KEY_LENGTH];
|
||
|
u8 k1[AES_KEY_LENGTH];
|
||
|
u8 *cbc_chain_data;
|
||
|
unsigned i;
|
||
|
|
||
|
cbc_chain_data = zero_key; /* Convenient array of 0's for IV */
|
||
|
|
||
|
/* compute K1 constant needed by AES-CMAC calculation */
|
||
|
for (i = 0; i < AES_KEY_LENGTH; i++)
|
||
|
tmp_data[i] = 0;
|
||
|
|
||
|
encrypt_object(key_schedule, tmp_data, left, 1);
|
||
|
debug_print_vector("AES(key, nonce)", AES_KEY_LENGTH, left);
|
||
|
|
||
|
left_shift_vector(left, k1, sizeof(left));
|
||
|
debug_print_vector("L", AES_KEY_LENGTH, left);
|
||
|
|
||
|
if ((left[0] >> 7) != 0) /* get MSB of L */
|
||
|
k1[AES_KEY_LENGTH-1] ^= AES_CMAC_CONST_RB;
|
||
|
debug_print_vector("K1", AES_KEY_LENGTH, k1);
|
||
|
|
||
|
/* compute the AES-CMAC value */
|
||
|
for (i = 0; i < num_aes_blocks; i++) {
|
||
|
/* Apply the chain data */
|
||
|
apply_cbc_chain_data(cbc_chain_data, src, tmp_data);
|
||
|
|
||
|
/* for the final block, XOR K1 into the IV */
|
||
|
if (i == num_aes_blocks - 1)
|
||
|
apply_cbc_chain_data(tmp_data, k1, tmp_data);
|
||
|
|
||
|
/* encrypt the AES block */
|
||
|
aes_encrypt(tmp_data, key_schedule, dst);
|
||
|
|
||
|
debug("sign_obj: block %d of %d\n", i, num_aes_blocks);
|
||
|
debug_print_vector("AES-CMAC Src", AES_KEY_LENGTH, src);
|
||
|
debug_print_vector("AES-CMAC Xor", AES_KEY_LENGTH, tmp_data);
|
||
|
debug_print_vector("AES-CMAC Dst", AES_KEY_LENGTH, dst);
|
||
|
|
||
|
/* Update pointers for next loop. */
|
||
|
cbc_chain_data = dst;
|
||
|
src += AES_KEY_LENGTH;
|
||
|
}
|
||
|
|
||
|
debug_print_vector("AES-CMAC Hash", AES_KEY_LENGTH, dst);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Encrypt and sign a block of data (depending on security mode).
|
||
|
*
|
||
|
* \param key Input AES key, length AES_KEY_LENGTH
|
||
|
* \param oper Security operations mask to perform (enum security_op)
|
||
|
* \param src Source data
|
||
|
* \param length Size of source data
|
||
|
* \param sig_dst Destination address for signature, AES_KEY_LENGTH bytes
|
||
|
*/
|
||
|
static int encrypt_and_sign(u8 *key, enum security_op oper, u8 *src,
|
||
|
u32 length, u8 *sig_dst)
|
||
|
{
|
||
|
u32 num_aes_blocks;
|
||
|
u8 key_schedule[AES_EXPAND_KEY_LENGTH];
|
||
|
|
||
|
debug("encrypt_and_sign: length = %d\n", length);
|
||
|
debug_print_vector("AES key", AES_KEY_LENGTH, key);
|
||
|
|
||
|
/*
|
||
|
* The only need for a key is for signing/checksum purposes, so
|
||
|
* if not encrypting, expand a key of 0s.
|
||
|
*/
|
||
|
aes_expand_key(oper & SECURITY_ENCRYPT ? key : zero_key, key_schedule);
|
||
|
|
||
|
num_aes_blocks = (length + AES_KEY_LENGTH - 1) / AES_KEY_LENGTH;
|
||
|
|
||
|
if (oper & SECURITY_ENCRYPT) {
|
||
|
/* Perform this in place, resulting in src being encrypted. */
|
||
|
debug("encrypt_and_sign: begin encryption\n");
|
||
|
encrypt_object(key_schedule, src, src, num_aes_blocks);
|
||
|
debug("encrypt_and_sign: end encryption\n");
|
||
|
}
|
||
|
|
||
|
if (oper & SECURITY_SIGN) {
|
||
|
/* encrypt the data, overwriting the result in signature. */
|
||
|
debug("encrypt_and_sign: begin signing\n");
|
||
|
sign_object(key, key_schedule, src, sig_dst, num_aes_blocks);
|
||
|
debug("encrypt_and_sign: end signing\n");
|
||
|
}
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
int sign_data_block(u8 *source, unsigned length, u8 *signature)
|
||
|
{
|
||
|
return encrypt_and_sign(zero_key, SECURITY_SIGN, source,
|
||
|
length, signature);
|
||
|
}
|