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AP_Beacon: Corrected possible use of nullptr memory.

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The check for UART port pointer is not sufficient
to know if the update() was possible or not. When
MarvelmindHedge construction failed, the hedge pointer
might be a nullptr and there are no checks to avoid
nullptr dereference.

The MarvelmindHedge structure had complex initialization
but was done in a C style, with intermixed initialization functions.
malloc() was changed to cleaner new operator. Given that the
file already contained new operator calls it didn't make
sense to have a mix. The files are cpp so C++ operators
are used.
This commit is contained in:
Paulo Neves 2017-10-30 23:56:01 +01:00 committed by Randy Mackay
parent 7d91755bd1
commit 4108f22304
2 changed files with 32 additions and 40 deletions
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62
libraries/AP_Beacon/AP_Beacon_Marvelmind.cpp
View File

@ -22,6 +22,11 @@
#include "AP_Beacon_Marvelmind.h"
#define AP_BEACON_MARVELMIND_POSITION_DATAGRAM_ID 0x0001
#define AP_BEACON_MARVELMIND_POSITIONS_DATAGRAM_ID 0x0002
#define AP_BEACON_MARVELMIND_POSITION_DATAGRAM_HIGHRES_ID 0x0011
#define AP_BEACON_MARVELMIND_POSITIONS_DATAGRAM_HIGHRES_ID 0x0012
extern const AP_HAL::HAL& hal;
AP_Beacon_Marvelmind::AP_Beacon_Marvelmind(AP_Beacon &frontend, AP_SerialManager &serial_manager) :
@ -32,14 +37,12 @@ AP_Beacon_Marvelmind::AP_Beacon_Marvelmind(AP_Beacon &frontend, AP_SerialManager
uart->begin(serial_manager.find_baudrate(AP_SerialManager::SerialProtocol_Beacon, 0));
hedge = new MarvelmindHedge();
last_update_ms = 0;
if (hedge) {
create_marvelmind_hedge();
if (hedge && hedge->position_buffer != nullptr) {
parse_state = RECV_HDR; // current state of receive data
num_bytes_in_block_received = 0; // bytes received
data_id = 0;
start_marvelmind_hedge();
} else {
// initialising beacon failed
hal.console->printf("MarvelMind: MarvelmindHedge failed\n");
}
}
}
@ -213,7 +216,7 @@ void AP_Beacon_Marvelmind::process_beacons_positions_highres_datagram()
void AP_Beacon_Marvelmind::update(void)
{
if (uart == nullptr) {
if (uart == nullptr || hedge == nullptr || hedge->position_buffer == nullptr) {
return;
}
// read any available characters
@ -329,37 +332,32 @@ void AP_Beacon_Marvelmind::update(void)
//////////////////////////////////////////////////////////////////////////////
// Create and initialize MarvelmindHedge structure
//////////////////////////////////////////////////////////////////////////////
void AP_Beacon_Marvelmind::create_marvelmind_hedge()
AP_Beacon_Marvelmind::MarvelmindHedge::MarvelmindHedge() :
max_buffered_positions{3},
position_buffer{nullptr},
positions_beacons{},
pause{false},
receive_data_callback{nullptr},
_last_values_count{0},
_last_values_next{0},
_have_new_values{false}
{
hedge->max_buffered_positions = 3;
hedge->position_buffer = nullptr;
hedge->verbose = false;
hedge->receive_data_callback = nullptr;
hedge->_last_values_count = 0;
hedge->_last_values_next = 0;
hedge->_have_new_values = false;
hedge->termination_required = false;
}
//////////////////////////////////////////////////////////////////////////////
// Initialize and start work
//////////////////////////////////////////////////////////////////////////////
void AP_Beacon_Marvelmind::start_marvelmind_hedge()
{
hedge->position_buffer = (PositionValue*) malloc(sizeof(struct PositionValue) * hedge->max_buffered_positions);
if (hedge->position_buffer == nullptr) {
if (hedge->verbose) {
hal.console->printf("MarvelMind: Not enough memory");
}
hedge->termination_required = true;
position_buffer = new PositionValue[max_buffered_positions];
if (position_buffer == nullptr) {
hal.console->printf("MarvelMind: Not enough memory\n");
return;
}
for (uint8_t i = 0; i < hedge->max_buffered_positions; i++) {
hedge->position_buffer[i].ready = false;
hedge->position_buffer[i].processed = false;
for (uint8_t i = 0; i < max_buffered_positions; i++) {
position_buffer[i].ready = false;
position_buffer[i].processed = false;
}
hedge->positions_beacons.num_beacons = 0;
hedge->positions_beacons.updated = false;
positions_beacons.num_beacons = 0;
positions_beacons.updated = false;
}
AP_Beacon_Marvelmind::MarvelmindHedge::~MarvelmindHedge() {
if (position_buffer != nullptr)
delete[] position_buffer;
}
bool AP_Beacon_Marvelmind::healthy()

10
libraries/AP_Beacon/AP_Beacon_Marvelmind.h
View File

@ -23,10 +23,6 @@
#pragma once
#define AP_BEACON_MARVELMIND_POSITION_DATAGRAM_ID 0x0001
#define AP_BEACON_MARVELMIND_POSITIONS_DATAGRAM_ID 0x0002
#define AP_BEACON_MARVELMIND_POSITION_DATAGRAM_HIGHRES_ID 0x0011
#define AP_BEACON_MARVELMIND_POSITIONS_DATAGRAM_HIGHRES_ID 0x0012
#define AP_BEACON_MARVELMIND_BUF_SIZE 255
#include "AP_Beacon_Backend.h"
@ -72,12 +68,12 @@ private:
struct MarvelmindHedge
{
MarvelmindHedge();
~MarvelmindHedge();
uint8_t max_buffered_positions; // maximum count of measurements of coordinates stored in buffer, default: 3
PositionValue * position_buffer; // buffer of measurements
StationaryBeaconsPositions positions_beacons;
bool verbose; // verbose flag which activate console output, default: False
bool pause; // pause flag. If True, class would not read serial data
bool termination_required; // If True, thread would exit from main loop and stop
void (*receive_data_callback)(PositionValue position); // receive_data_callback is callback function to receive data
uint8_t _last_values_count;
@ -103,8 +99,6 @@ private:
void process_beacons_positions_highres_datagram();
void process_position_highres_datagram(PositionValue &p);
void process_position_datagram(PositionValue &p);
void create_marvelmind_hedge();
void start_marvelmind_hedge();
void set_stationary_beacons_positions_and_distances();
void order_stationary_beacons();