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/*
* Copyright (C) 2016 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2 as published by the
* Free Software Foundation.
*/
#include <common.h>
#include <dma.h>
#include <digest.h>
#include <driver.h>
#include <init.h>
#include <blobgen.h>
#include <stdlib.h>
#include <crypto.h>
#include <crypto/sha.h>
#include "scc.h"
#define MAX_IVLEN BLOCKSIZE_BYTES
static struct digest *sha256;
static int sha256sum(uint8_t *src, uint8_t *dst, unsigned int size)
{
if (!sha256)
sha256 = digest_alloc("sha256");
if (!sha256) {
pr_err("Unable to allocate sha256 digest\n");
return -EINVAL;
}
return digest_digest(sha256, src, size, dst);
}
static int imx_scc_blob_encrypt(struct blobgen *bg, const char *modifier,
const void *plain, int plainsize, void *blob,
int *blobsize)
{
char *s;
int bufsiz;
struct ablkcipher_request req = {};
uint8_t iv[MAX_IVLEN];
uint8_t hash[SHA256_DIGEST_SIZE];
int ret;
bufsiz = ALIGN(plainsize + KEYMOD_LENGTH, 8);
s = malloc(bufsiz + SHA256_DIGEST_SIZE);
if (!s)
return -ENOMEM;
memset(s, 0, bufsiz);
strncpy(s, modifier, KEYMOD_LENGTH);
memcpy(s + KEYMOD_LENGTH, plain, plainsize);
ret = sha256sum(s, hash, bufsiz);
if (ret)
goto out;
memcpy(s + bufsiz, hash, SHA256_DIGEST_SIZE);
bufsiz += SHA256_DIGEST_SIZE;
req.info = iv;
req.src = s;
req.dst = blob;
req.nbytes = bufsiz;
get_random_bytes(req.info, MAX_IVLEN);
ret = imx_scc_cbc_des_encrypt(&req);
if (ret)
goto out;
memcpy(blob + bufsiz, req.info, MAX_IVLEN);
*blobsize = bufsiz + MAX_IVLEN;
out:
free(s);
return ret;
}
static int imx_scc_blob_decrypt(struct blobgen *bg, const char *modifier,
const void *blob, int blobsize, void **plain,
int *plainsize)
{
struct ablkcipher_request req = {};
uint8_t iv[MAX_IVLEN];
uint8_t hash[SHA256_DIGEST_SIZE];
int ret;
uint8_t *data;
int ciphersize = blobsize - MAX_IVLEN;
if (blobsize <= MAX_IVLEN + SHA256_DIGEST_SIZE + KEYMOD_LENGTH)
return -EINVAL;
data = malloc(ciphersize);
if (!data)
return -ENOMEM;
req.info = iv;
req.nbytes = ciphersize;
req.src = (void *)blob;
req.dst = data;
memcpy(req.info, blob + req.nbytes, MAX_IVLEN);
ret = imx_scc_cbc_des_decrypt(&req);
if (ret)
goto out;
ret = sha256sum(data, hash, ciphersize - SHA256_DIGEST_SIZE);
if (ret)
goto out;
if (memcmp(data + ciphersize - SHA256_DIGEST_SIZE, hash,
SHA256_DIGEST_SIZE)) {
pr_err("%s: Corrupted SHA256 digest. Can't continue.\n",
bg->dev.name);
pr_err("%s: Calculated hash:\n", bg->dev.name);
memory_display(hash, 0, SHA256_DIGEST_SIZE, 1, 0);
pr_err("%s: Received hash:\n", bg->dev.name);
memory_display(data + ciphersize - SHA256_DIGEST_SIZE,
0, SHA256_DIGEST_SIZE, 1, 0);
ret = -EILSEQ;
goto out;
}
*plainsize = ciphersize - SHA256_DIGEST_SIZE - KEYMOD_LENGTH;
*plain = xmemdup(data + KEYMOD_LENGTH, *plainsize);
out:
free(data);
return ret;
}
int imx_scc_blob_gen_probe(struct device_d *dev)
{
struct blobgen *bg;
int ret;
bg = xzalloc(sizeof(*bg));
bg->max_payload_size = MAX_BLOB_LEN - MAX_IVLEN -
SHA256_DIGEST_SIZE - KEYMOD_LENGTH;
bg->encrypt = imx_scc_blob_encrypt;
bg->decrypt = imx_scc_blob_decrypt;
ret = blob_gen_register(dev, bg);
if (ret)
free(bg);
return ret;
}
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