u-boot/lib/aes/aes-encrypt.c
Philippe Reynes a6982a6f76 fit: cipher: aes: allow to store the IV in the FIT image
Binaries may be encrypted in a FIT image with AES. This
algo needs a key and an IV (Initialization Vector). The
IV is provided in a file (pointer by iv-name-hint in the
ITS file) when building the ITB file.

This commits adds provide an alternative way to manage
the IV. If the property iv-name-hint is not provided in
the ITS file, the tool mkimage will generate an random
IV and store it in the FIT image.

Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
2020-10-12 21:30:37 -04:00

151 lines
3.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2019,Softathome
*/
#include "mkimage.h"
#include <stdio.h>
#include <string.h>
#include <image.h>
#include <time.h>
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <openssl/evp.h>
#include <openssl/engine.h>
#include <uboot_aes.h>
#if OPENSSL_VERSION_NUMBER >= 0x10000000L
#define HAVE_ERR_REMOVE_THREAD_STATE
#endif
int image_aes_encrypt(struct image_cipher_info *info,
unsigned char *data, int size,
unsigned char **cipher, int *cipher_len)
{
EVP_CIPHER_CTX *ctx;
unsigned char *buf = NULL;
int buf_len, len, ret = 0;
/* create and initialise the context */
ctx = EVP_CIPHER_CTX_new();
if (!ctx) {
printf("Can't create context\n");
return -1;
}
/* allocate a buffer for the result */
buf = malloc(size + AES_BLOCK_LENGTH);
if (!buf) {
printf("Can't allocate memory to encrypt\n");
ret = -1;
goto out;
}
if (EVP_EncryptInit_ex(ctx, info->cipher->calculate_type(),
NULL, info->key, info->iv) != 1) {
printf("Can't init encryption\n");
ret = -1;
goto out;
}
if (EVP_EncryptUpdate(ctx, buf, &len, data, size) != 1) {
printf("Can't encrypt data\n");
ret = -1;
goto out;
}
buf_len = len;
if (EVP_EncryptFinal_ex(ctx, buf + len, &len) != 1) {
printf("Can't finalise the encryption\n");
ret = -1;
goto out;
}
buf_len += len;
*cipher = buf;
*cipher_len = buf_len;
out:
EVP_CIPHER_CTX_free(ctx);
return ret;
}
int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest,
void *fit, int node_noffset)
{
int parent, node;
char name[128];
int ret = 0;
/* Either create or overwrite the named cipher node */
parent = fdt_subnode_offset(keydest, 0, FIT_CIPHER_NODENAME);
if (parent == -FDT_ERR_NOTFOUND) {
parent = fdt_add_subnode(keydest, 0, FIT_CIPHER_NODENAME);
if (parent < 0) {
ret = parent;
if (ret != -FDT_ERR_NOSPACE) {
fprintf(stderr,
"Couldn't create cipher node: %s\n",
fdt_strerror(parent));
}
}
}
if (ret)
goto done;
/* Either create or overwrite the named key node */
if (info->ivname)
snprintf(name, sizeof(name), "key-%s-%s-%s",
info->name, info->keyname, info->ivname);
else
snprintf(name, sizeof(name), "key-%s-%s",
info->name, info->keyname);
node = fdt_subnode_offset(keydest, parent, name);
if (node == -FDT_ERR_NOTFOUND) {
node = fdt_add_subnode(keydest, parent, name);
if (node < 0) {
ret = node;
if (ret != -FDT_ERR_NOSPACE) {
fprintf(stderr,
"Could not create key subnode: %s\n",
fdt_strerror(node));
}
}
} else if (node < 0) {
fprintf(stderr, "Cannot select keys parent: %s\n",
fdt_strerror(node));
ret = node;
}
if (ret)
goto done;
if (info->ivname)
/* Store the IV in the u-boot device tree */
ret = fdt_setprop(keydest, node, "iv",
info->iv, info->cipher->iv_len);
else
/* Store the IV in the FIT image */
ret = fdt_setprop(fit, node_noffset, "iv",
info->iv, info->cipher->iv_len);
if (!ret)
ret = fdt_setprop(keydest, node, "key",
info->key, info->cipher->key_len);
if (!ret)
ret = fdt_setprop_u32(keydest, node, "key-len",
info->cipher->key_len);
done:
if (ret)
ret = ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
return ret;
}