mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-26 21:13:48 +00:00
143 lines
3.9 KiB
C
143 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
/*
|
|
* Copyright (c) 2011 The Chromium OS Authors.
|
|
* (C) Copyright 2010 - 2011 NVIDIA Corporation <www.nvidia.com>
|
|
*/
|
|
|
|
#include <common.h>
|
|
#include <log.h>
|
|
#include <linux/errno.h>
|
|
#include "crypto.h"
|
|
#include "uboot_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 */
|
|
};
|
|
|
|
/**
|
|
* 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 AES128_KEY_LENGTH
|
|
* \param key_schedule Expanded key to use
|
|
* \param src Source data of length 'num_aes_blocks' blocks
|
|
* \param dst Destination buffer, length AES128_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[AES128_KEY_LENGTH];
|
|
u8 iv[AES128_KEY_LENGTH] = {0};
|
|
u8 left[AES128_KEY_LENGTH];
|
|
u8 k1[AES128_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 < AES128_KEY_LENGTH; i++)
|
|
tmp_data[i] = 0;
|
|
|
|
aes_cbc_encrypt_blocks(AES128_KEY_LENGTH, key_schedule, iv,
|
|
tmp_data, left, 1);
|
|
|
|
left_shift_vector(left, k1, sizeof(left));
|
|
|
|
if ((left[0] >> 7) != 0) /* get MSB of L */
|
|
k1[AES128_KEY_LENGTH - 1] ^= AES_CMAC_CONST_RB;
|
|
|
|
/* compute the AES-CMAC value */
|
|
for (i = 0; i < num_aes_blocks; i++) {
|
|
/* Apply the chain data */
|
|
aes_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)
|
|
aes_apply_cbc_chain_data(tmp_data, k1, tmp_data);
|
|
|
|
/* encrypt the AES block */
|
|
aes_encrypt(AES128_KEY_LENGTH, tmp_data,
|
|
key_schedule, dst);
|
|
|
|
debug("sign_obj: block %d of %d\n", i, num_aes_blocks);
|
|
|
|
/* Update pointers for next loop. */
|
|
cbc_chain_data = dst;
|
|
src += AES128_KEY_LENGTH;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Encrypt and sign a block of data (depending on security mode).
|
|
*
|
|
* \param key Input AES key, length AES128_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, AES128_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[AES128_EXPAND_KEY_LENGTH];
|
|
u8 iv[AES128_KEY_LENGTH] = {0};
|
|
|
|
debug("encrypt_and_sign: length = %d\n", length);
|
|
|
|
/*
|
|
* 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,
|
|
AES128_KEY_LENGTH, key_schedule);
|
|
|
|
num_aes_blocks = (length + AES128_KEY_LENGTH - 1) / AES128_KEY_LENGTH;
|
|
|
|
if (oper & SECURITY_ENCRYPT) {
|
|
/* Perform this in place, resulting in src being encrypted. */
|
|
debug("encrypt_and_sign: begin encryption\n");
|
|
aes_cbc_encrypt_blocks(AES128_KEY_LENGTH, key_schedule, iv, 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);
|
|
}
|