ICFS/src/ui-socket.c

/*
  ICFS: Interactively Controlled File System
  Copyright (C) 2024-2025  Fedir Kovalov

  This program can be distributed under the terms of the GNU GPLv2.
  See the file LICENSE.
*/

#include "access_t.h"
#include <stddef.h>
#include <sys/types.h>
#include <time.h>
#define _GNU_SOURCE
#include "perm_permissions_table.h"
#include "temp_permissions_table.h"
#include "ui-socket.h"
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>

#define ZENITY_TEMP_ALLOW_MESSAGE "Allow this time\n"

int init_ui_socket(const char *perm_permissions_db_filename) {
  FILE *fp = NULL;

  if (init_temp_permissions_table()) {
    fprintf(stderr, "Could not initialize temporary permissions table.\n");
    return 1;
  }

  if (init_perm_permissions_table(perm_permissions_db_filename)) {
    fprintf(stderr, "Could not initialize permanent permissions table.\n");
    return 1;
  }

  // Test if Zenity is installed (get version)
  fp = popen("zenity --version", "r");
  if (fp == NULL) {
    perror("Pipe returned an error");
    return 1;
  }

  pclose(fp);
  return 0;
}

void destroy_ui_socket(void) {
  destroy_temp_permissions_table();
  destroy_perm_permissions_table();
}

/**
 * Asks the user if the process should be allowed to access the file using the
 * GUI
 *
 * @param filename: The file that the process is trying to access
 * @param pi: The process information
 * @return: access status - ALLOW, DENY or ALLOW_TEMP
 * allowed for the runtime of the process
 */
access_t ask_access(const char *filename, struct process_info proc_info) {
  FILE *fp = NULL;
  char *command = NULL;
  int ret =
      asprintf(&command,
               "zenity --question --extra-button \"Allow this time\" --title "
               "\"Allow Access?\" --text \"Allow process "
               "<tt>%s</tt> with PID <tt>%d</tt> to access <tt>%s</tt>\"",
               proc_info.name, proc_info.PID, filename);

  if (ret < 0) {
    // If asprintf fails, the contents of command are undefined (see man
    // asprintf). That does not explicitly rule out that command will be a valid
    // pointer. But the risk of freeing a non-allocated pointer is too much to
    // justify preparing for this.
    fprintf(stderr, "Could not create query on rule insertion");
    perror("");
    return 1;
  }

  // Zenity Question Message Popup
  fp = popen(command, "r");
  free(command);

  if (fp == NULL) {
    perror("Pipe returned a error");
    return DENY;
  }

  // if the user clicks the "Allow this time" button, `zenity` will only
  // write it to `stdout`, but the exit code will still be `1`. So, we need
  // to manually check the output.
  char buffer[sizeof(ZENITY_TEMP_ALLOW_MESSAGE) + 1];
  while (fgets(buffer, sizeof(buffer), fp)) {
    printf("%s", buffer);
    if (strcmp(buffer, ZENITY_TEMP_ALLOW_MESSAGE) == 0) {
      pclose(fp);
      return ALLOW_TEMP;
    }
  }

  int zenity_exit_code = WEXITSTATUS(pclose(fp));
  fprintf(stderr, "zenity returned %d\n", zenity_exit_code);
  // zenity returns 1 on "No" >:(
  if (zenity_exit_code == 0) {
    return ALLOW;
  }

  return DENY;
}

/**
 * Check access according to:
 * 1. temp permission table
 * 2. permanent permission table
 * 3. user descision
 *
 * @param filename: The file that the process is trying to access
 * @pram pi: The process information
 * @param opts: options (GRANT_TEMP, GRANT_PERM)
 * @return: 0 if access is denied, 1 if access is allowed
 */
int interactive_access(const char *filename, struct process_info proc_info,
                       int opts) {

  access_t access = check_temp_access(filename, proc_info);
  if (access == ALLOW) {
    return 1;
  }
  if (access == DENY) {
    return 0;
  }

  access = check_perm_access(filename, proc_info);
  if (access == ALLOW) {
    return 1;
  }
  if (access == DENY) {
    return 0;
  }

  // if noth GRANT_TEMP and GRANT_PERM are selected, then only permanent
  // permissions are granted

  if (opts & GRANT_PERM) {
    give_perm_access(filename, proc_info);
    return 1;
  }
  if (opts & GRANT_TEMP) {
    set_temp_access(filename, proc_info, SET_ALLOW);
    return 1;
  }

  access_t user_response = ask_access(filename, proc_info);
  if (user_response == ALLOW) {
    give_perm_access(filename, proc_info);
    return 1;
  }

  if (user_response == ALLOW_TEMP) {
    set_temp_access(filename, proc_info, SET_ALLOW);
    return 1;
  }

  if (user_response == DENY) {
    set_temp_access(filename, proc_info, SET_DENY);
    return 0;
  }

  // deny on unknown options.
  return 0;
}