Files
esp-idf/components/nvs_flash/src/nvs_encrypted_partition.cpp
T

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3.5 KiB
C++

/*
* SPDX-FileCopyrightText: 2019-2026 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <cstring>
#include "nvs_encrypted_partition.hpp"
#include "nvs_types.hpp"
#include "nvs_constants.h"
#include "nvs_xts_aes.h"
namespace nvs {
#ifdef CONFIG_NVS_BDL_STACK
NVSEncryptedPartition::NVSEncryptedPartition(const char* label, const esp_blockdev_handle_t bdl, const bool managed_bdl)
: NVSPartition(label, bdl, managed_bdl) { }
#else
NVSEncryptedPartition::NVSEncryptedPartition(const esp_partition_t *partition)
: NVSPartition(partition) { }
#endif // CONFIG_NVS_BDL_STACK
esp_err_t NVSEncryptedPartition::init(nvs_sec_cfg_t* cfg)
{
uint8_t* eky = reinterpret_cast<uint8_t*>(cfg);
XTS_FUNC(xts_init)(&mEctxt);
XTS_FUNC(xts_init)(&mDctxt);
if (XTS_FUNC(xts_setkey_enc)(&mEctxt, eky, 2 * NVS_KEY_SIZE * 8) != 0) {
return ESP_ERR_NVS_XTS_CFG_FAILED;
}
if (XTS_FUNC(xts_setkey_dec)(&mDctxt, eky, 2 * NVS_KEY_SIZE * 8) != 0) {
return ESP_ERR_NVS_XTS_CFG_FAILED;
}
return ESP_OK;
}
esp_err_t NVSEncryptedPartition::read(size_t src_offset, void* dst, size_t size)
{
// Currently upper layer of NVS reads entries one by one even for variable size
// multi-entry data types. So length should always be equal to size of an entry.
// here we make sure that the size is really compliant with the minimal encryption block size.
if (size % NVS_ENCRYPT_BLOCK_SIZE != 0) return ESP_ERR_INVALID_SIZE;
// read data
esp_err_t read_result = NVSPartition::read(src_offset, dst, size);
if (read_result != ESP_OK) {
return read_result;
}
// decrypt data
//sector num required as an arr by mbedtls. Should have been just uint64/32.
uint8_t data_unit[NVS_ENCRYPT_BLOCK_SIZE];
uint32_t relAddr = src_offset;
memset(data_unit, 0, sizeof(data_unit));
memcpy(data_unit, &relAddr, sizeof(relAddr));
uint8_t *destination = reinterpret_cast<uint8_t*>(dst);
if (XTS_FUNC(crypt_xts)(&mDctxt, XTS_MODE(DECRYPT), size, data_unit, destination, destination) != 0) {
return ESP_ERR_NVS_XTS_DECR_FAILED;
}
return ESP_OK;
}
esp_err_t NVSEncryptedPartition::write(size_t addr, const void* src, size_t size)
{
if (size % NVS_ENCRYPT_BLOCK_SIZE != 0) return ESP_ERR_INVALID_SIZE;
// copy data to buffer for encryption
uint8_t* buf = new (std::nothrow) uint8_t [size];
if (!buf) return ESP_ERR_NO_MEM;
memcpy(buf, src, size);
// encrypt data
uint8_t entrySize = sizeof(Item);
//sector num required as an arr by mbedtls. Should have been just uint64/32.
uint8_t data_unit[NVS_ENCRYPT_BLOCK_SIZE];
/* Use relative address instead of absolute address (relocatable), so that host-generated
* encrypted nvs images can be used*/
uint32_t relAddr = addr;
memset(data_unit, 0, sizeof(data_unit));
for(uint8_t entry = 0; entry < (size/entrySize); entry++)
{
uint32_t offset = entry * entrySize;
uint32_t *addr_loc = (uint32_t*) &data_unit[0];
*addr_loc = relAddr + offset;
if (XTS_FUNC(crypt_xts)(&mEctxt,
XTS_MODE(ENCRYPT),
entrySize,
data_unit,
buf + offset,
buf + offset) != 0) {
delete [] buf;
return ESP_ERR_NVS_XTS_ENCR_FAILED;
}
}
// write data
esp_err_t result = NVSPartition::write(addr, buf, size);
delete [] buf;
return result;
}
} // nvs