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DFU: disable CRC checks based on the init packet.

master
Rohit Grover 2015-06-09 08:10:04 +01:00
parent d7f869bda7
commit 4d24dc24c9
1 changed files with 157 additions and 155 deletions
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312
nordic-sdk/components/libraries/bootloader_dfu/dfu_init_template.c
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@ -1,155 +1,157 @@
/* Copyright (c) 2014 Nordic Semiconductor. All Rights Reserved.
*
* The information contained herein is property of Nordic Semiconductor ASA.
* Terms and conditions of usage are described in detail in NORDIC
* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
*
* Licensees are granted free, non-transferable use of the information. NO
* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
* the file.
*
*/
/**@file
*
* @defgroup nrf_dfu_init_template Template file with an DFU init packet handling example.
* @{
*
* @ingroup nrf_dfu
*
* @brief This file contains a template on how to implement DFU init packet handling.
*
* @details The template shows how device type and revision can be used for a safety check of the
* received image. It shows how validation can be performed in two stages:
* - Stage 1: Pre-check of firmware image before transfer to ensure the firmware matches:
* - Device Type.
* - Device Revision.
* Installed SoftDevice.
* This template can be extended with additional checks according to needs.
* For example, such a check could be the origin of the image (trusted source)
* based on a signature scheme.
* - Stage 2: Post-check of the image after image transfer but before installing firmware.
* For example, such a check could be an integrity check in form of hashing or
* verification of a signature.
* In this template, a simple CRC check is carried out.
* The CRC check can be replaced with other mechanisms, like signing.
*
* @note This module does not support security features such as image signing, but the
* implementation allows for such extension.
* If the init packet is signed by a trusted source, it must be decrypted before it can be
* processed.
*/
#include "dfu_init.h"
#include <stdint.h>
#include <string.h>
#include "dfu_types.h"
#include "nrf_error.h"
#include "crc16.h"
#define DFU_INIT_PACKET_EXT_LENGTH_MIN 2 //< Minimum length of the extended init packet. The extended init packet may contain a CRC, a HASH, or other data. This value must be changed according to the requirements of the system. The template uses a minimum value of two in order to hold a CRC. */
#define DFU_INIT_PACKET_EXT_LENGTH_MAX 10 //< Maximum length of the extended init packet. The extended init packet may contain a CRC, a HASH, or other data. This value must be changed according to the requirements of the system. The template uses a maximum value of 10 in order to hold a CRC and any padded data on transport layer without overflow. */
static uint8_t m_extended_packet[DFU_INIT_PACKET_EXT_LENGTH_MAX]; //< Data array for storage of the extended data received. The extended data follows the normal init data of type \ref dfu_init_packet_t. Extended data can be used for a CRC, hash, signature, or other data. */
static uint8_t m_extended_packet_length; //< Length of the extended data received with init packet. */
uint32_t dfu_init_prevalidate(uint8_t * p_init_data, uint32_t init_data_len)
{
uint32_t i = 0;
// In order to support signing or encryption then any init packet decryption function / library
// should be called from here or implemented at this location.
// Length check to ensure valid data are parsed.
if (init_data_len < sizeof(dfu_init_packet_t))
{
return NRF_ERROR_INVALID_LENGTH;
}
// Current template uses clear text data so they can be casted for pre-check.
dfu_init_packet_t * p_init_packet = (dfu_init_packet_t *)p_init_data;
m_extended_packet_length = ((uint32_t)p_init_data + init_data_len) -
(uint32_t)&p_init_packet->softdevice[p_init_packet->softdevice_len];
if (m_extended_packet_length < DFU_INIT_PACKET_EXT_LENGTH_MIN)
{
return NRF_ERROR_INVALID_LENGTH;
}
if (((uint32_t)p_init_data + init_data_len) <
(uint32_t)&p_init_packet->softdevice[p_init_packet->softdevice_len])
{
return NRF_ERROR_INVALID_LENGTH;
}
memcpy(m_extended_packet,
&p_init_packet->softdevice[p_init_packet->softdevice_len],
m_extended_packet_length);
/** [DFU init application version] */
// To support application versioning, this check should be updated.
// This template allows for any application to be installed. However,
// customers can place a revision number at the bottom of the application
// to be verified by the bootloader. This can be done at a location
// relative to the application, for example the application start
// address + 0x0100.
/** [DFU init application version] */
// First check to verify the image to be transfered matches the device type.
// If no Device type is present in DFU_DEVICE_INFO then any image will be accepted.
if ((DFU_DEVICE_INFO->device_type != DFU_DEVICE_TYPE_EMPTY) &&
(p_init_packet->device_type != DFU_DEVICE_INFO->device_type))
{
return NRF_ERROR_INVALID_DATA;
}
// Second check to verify the image to be transfered matches the device revision.
// If no Device revision is present in DFU_DEVICE_INFO then any image will be accepted.
if ((DFU_DEVICE_INFO->device_rev != DFU_DEVICE_REVISION_EMPTY) &&
(p_init_packet->device_rev != DFU_DEVICE_INFO->device_rev))
{
return NRF_ERROR_INVALID_DATA;
}
// Third check: Check the array of supported SoftDevices by this application.
// If the installed SoftDevice does not match any SoftDevice in the list then an
// error is returned.
while (i < p_init_packet->softdevice_len)
{
if (p_init_packet->softdevice[i] == DFU_SOFTDEVICE_ANY ||
p_init_packet->softdevice[i++] == SOFTDEVICE_INFORMATION->firmware_id)
{
return NRF_SUCCESS;
}
}
// No matching SoftDevice found - Return NRF_ERROR_INVALID_DATA.
return NRF_ERROR_INVALID_DATA;
}
uint32_t dfu_init_postvalidate(uint8_t * p_image, uint32_t image_len)
{
uint16_t image_crc;
uint16_t received_crc;
// In order to support hashing (and signing) then the (decrypted) hash should be fetched and
// the corresponding hash should be calculated over the image at this location.
// If hashing (or signing) is added to the system then the CRC validation should be removed.
// calculate CRC from active block.
image_crc = crc16_compute(p_image, image_len, NULL);
// Decode the received CRC from extended data.
received_crc = uint16_decode((uint8_t *)&m_extended_packet[0]);
// Compare the received and calculated CRC.
if (image_crc != received_crc)
{
return NRF_ERROR_INVALID_DATA;
}
return NRF_SUCCESS;
}
/* Copyright (c) 2014 Nordic Semiconductor. All Rights Reserved.
*
* The information contained herein is property of Nordic Semiconductor ASA.
* Terms and conditions of usage are described in detail in NORDIC
* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
*
* Licensees are granted free, non-transferable use of the information. NO
* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
* the file.
*
*/
/**@file
*
* @defgroup nrf_dfu_init_template Template file with an DFU init packet handling example.
* @{
*
* @ingroup nrf_dfu
*
* @brief This file contains a template on how to implement DFU init packet handling.
*
* @details The template shows how device type and revision can be used for a safety check of the
* received image. It shows how validation can be performed in two stages:
* - Stage 1: Pre-check of firmware image before transfer to ensure the firmware matches:
* - Device Type.
* - Device Revision.
* Installed SoftDevice.
* This template can be extended with additional checks according to needs.
* For example, such a check could be the origin of the image (trusted source)
* based on a signature scheme.
* - Stage 2: Post-check of the image after image transfer but before installing firmware.
* For example, such a check could be an integrity check in form of hashing or
* verification of a signature.
* In this template, a simple CRC check is carried out.
* The CRC check can be replaced with other mechanisms, like signing.
*
* @note This module does not support security features such as image signing, but the
* implementation allows for such extension.
* If the init packet is signed by a trusted source, it must be decrypted before it can be
* processed.
*/
#include "dfu_init.h"
#include <stdint.h>
#include <string.h>
#include "dfu_types.h"
#include "nrf_error.h"
#include "crc16.h"
#define DFU_INIT_PACKET_EXT_LENGTH_MIN 2 //< Minimum length of the extended init packet. The extended init packet may contain a CRC, a HASH, or other data. This value must be changed according to the requirements of the system. The template uses a minimum value of two in order to hold a CRC. */
#define DFU_INIT_PACKET_EXT_LENGTH_MAX 10 //< Maximum length of the extended init packet. The extended init packet may contain a CRC, a HASH, or other data. This value must be changed according to the requirements of the system. The template uses a maximum value of 10 in order to hold a CRC and any padded data on transport layer without overflow. */
static uint8_t m_extended_packet[DFU_INIT_PACKET_EXT_LENGTH_MAX]; //< Data array for storage of the extended data received. The extended data follows the normal init data of type \ref dfu_init_packet_t. Extended data can be used for a CRC, hash, signature, or other data. */
static uint8_t m_extended_packet_length; //< Length of the extended data received with init packet. */
uint32_t dfu_init_prevalidate(uint8_t * p_init_data, uint32_t init_data_len)
{
uint32_t i = 0;
// In order to support signing or encryption then any init packet decryption function / library
// should be called from here or implemented at this location.
// Length check to ensure valid data are parsed.
if (init_data_len < sizeof(dfu_init_packet_t))
{
return NRF_ERROR_INVALID_LENGTH;
}
// Current template uses clear text data so they can be casted for pre-check.
dfu_init_packet_t * p_init_packet = (dfu_init_packet_t *)p_init_data;
m_extended_packet_length = ((uint32_t)p_init_data + init_data_len) -
(uint32_t)&p_init_packet->softdevice[p_init_packet->softdevice_len];
if (m_extended_packet_length < DFU_INIT_PACKET_EXT_LENGTH_MIN)
{
return NRF_ERROR_INVALID_LENGTH;
}
if (((uint32_t)p_init_data + init_data_len) <
(uint32_t)&p_init_packet->softdevice[p_init_packet->softdevice_len])
{
return NRF_ERROR_INVALID_LENGTH;
}
memcpy(m_extended_packet,
&p_init_packet->softdevice[p_init_packet->softdevice_len],
m_extended_packet_length);
/** [DFU init application version] */
// To support application versioning, this check should be updated.
// This template allows for any application to be installed. However,
// customers can place a revision number at the bottom of the application
// to be verified by the bootloader. This can be done at a location
// relative to the application, for example the application start
// address + 0x0100.
/** [DFU init application version] */
// First check to verify the image to be transfered matches the device type.
// If no Device type is present in DFU_DEVICE_INFO then any image will be accepted.
if ((DFU_DEVICE_INFO->device_type != DFU_DEVICE_TYPE_EMPTY) &&
(p_init_packet->device_type != DFU_DEVICE_INFO->device_type))
{
return NRF_ERROR_INVALID_DATA;
}
// Second check to verify the image to be transfered matches the device revision.
// If no Device revision is present in DFU_DEVICE_INFO then any image will be accepted.
if ((DFU_DEVICE_INFO->device_rev != DFU_DEVICE_REVISION_EMPTY) &&
(p_init_packet->device_rev != DFU_DEVICE_INFO->device_rev))
{
return NRF_ERROR_INVALID_DATA;
}
// Third check: Check the array of supported SoftDevices by this application.
// If the installed SoftDevice does not match any SoftDevice in the list then an
// error is returned.
while (i < p_init_packet->softdevice_len)
{
if (p_init_packet->softdevice[i] == DFU_SOFTDEVICE_ANY ||
p_init_packet->softdevice[i++] == SOFTDEVICE_INFORMATION->firmware_id)
{
return NRF_SUCCESS;
}
}
// No matching SoftDevice found - Return NRF_ERROR_INVALID_DATA.
return NRF_ERROR_INVALID_DATA;
}
uint32_t dfu_init_postvalidate(uint8_t * p_image, uint32_t image_len)
{
#if NEED_CRC_CHECK /* disabled for now */
uint16_t image_crc;
uint16_t received_crc;
// In order to support hashing (and signing) then the (decrypted) hash should be fetched and
// the corresponding hash should be calculated over the image at this location.
// If hashing (or signing) is added to the system then the CRC validation should be removed.
// calculate CRC from active block.
image_crc = crc16_compute(p_image, image_len, NULL);
// Decode the received CRC from extended data.
received_crc = uint16_decode((uint8_t *)&m_extended_packet[0]);
// Compare the received and calculated CRC.
if (image_crc != received_crc)
{
return NRF_ERROR_INVALID_DATA;
}
#endif /* NEED_CRC_CHECK */
return NRF_SUCCESS;
}