C++/CURL - Passing data through PHP request the safe way? - php

Question

I'm trying to send data with curl to my PHP file and then I can do all the other actions like hashing password/data with salt, running database queries eco. It seems to work fine, but there's only one problem. I'm not sure how to secure it, with an authorization token for example. I want to be able to query data from my PHP file using the written application only. I can see how this would become a problem, if people had access to the link through web browser for example.
I've included my code below, if someone needs something similar.
main.cpp
#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <curl/curl.h>
#include <sha.h>
#include <hex.h>
using namespace std;
using namespace CryptoPP;
size_t size = 0;
size_t write_to_string(void *ptr, size_t size, size_t count, void *stream) {
((string*)stream)->append((char*)ptr, 0, size*count);
return size*count;
}
template <class T>
string QueryDB(initializer_list<T> list) // Use initialize_list to query an undefined number of params
{
CURL *curl;
CURLcode res;
string submitdata = "", query_result;
int i = 1;
for (auto elem : list) // For each param append to the submitdata string
{
if (i == 1) { // If first param, we append "?"
string d = "?" + to_string(i) + "=" + elem;
submitdata.append(d);
} else if (i > 1) { // If not first param, we append "&" as it's the second, third, fourth ... param
string d = "&" + to_string(i) + "=" + elem;
submitdata.append(d);
}
i++;
}
curl_global_init(CURL_GLOBAL_ALL);
curl = curl_easy_init();
if (curl)
{
string loginurl = string("http://localhost/login.php");
curl_easy_setopt(curl, CURLOPT_USERPWD, "randomhttpuser:randomhttppassword");
curl_easy_setopt(curl, CURLOPT_URL, (loginurl + submitdata).c_str());
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_to_string);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &query_result);
curl_easy_setopt(curl, CURLOPT_TIMEOUT, 20L);
res = curl_easy_perform(curl);
if (res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
curl_easy_cleanup(curl);
}
else {
query_result = "CONNECTION FAILED";
}
curl_global_cleanup();
return query_result;
}
string SHA256Hash(string input)
{
SHA256 hash;
string hashed_input;
StringSource ss(input, true, new HashFilter(hash, new HexEncoder(new StringSink(hashed_input))));
return hashed_input;
}
int main()
{
string username = "testuser";
string raw_password = "testpass";
// Hash password and send it as a query to PHP file
// query_result will hold the value of REQUEST response
auto hashed_password = SHA256Hash(raw_password);
auto query_result = QueryDB({ username, hashed_password });
cout << "=========================================== [ POST ] ===========================================" << endl;
cout << "User: " << username.c_str() << endl;
cout << "Raw Password: " << raw_password.c_str() << endl;
cout << "Hashed password: " << hashed_password.c_str() << endl;
cout << "========================================== [ REQUEST ] =========================================" << endl;
cout << query_result.c_str() << endl;
Sleep(15 * 1000);
return 0;
}
login.php
<?php
$reqparams = array();
function AddStringToArray($name,$string) {
global $reqparams;
$reqparams[$name] = $string;
}
/* Check if specified param exists in reqparams array */
function GetRequestParam($value) {
global $reqparams;
if (array_key_exists($value, $reqparams)) {
$returnvalue = $reqparams[$value];
} else {
$returnvalue = "INVALID PARAMETER";
}
return $returnvalue;
}
$authuser = "randomhttpuser";
$authpw = "randomhttppassword";
$authorized = False;
if (!isset($_SERVER['PHP_AUTH_USER'])) {
header('WWW-Authenticate: Basic realm="My Realm"');
header('HTTP/1.0 401 Unauthorized');
echo 'Failed to authorize!';
exit;
} else {
if($_SERVER['PHP_AUTH_USER'] == $authuser && $_SERVER['PHP_AUTH_PW'] == $authpw)
{
$authorized = True;
} else {
$authorized = False;
die('Failed to authorize!');
}
}
if($authorized == True)
{
/* Store each REQUEST and it's value in the $reqparams array using AddStringToArray function */
foreach ($_REQUEST as $key => $value)
{
$value = addslashes($value);
$value = strip_tags($value);
AddStringToArray($key, $value);
}
/* You should remember in which order you called the params in your REQUEST query or if you really want, you can just use:
$variable = $_REQUEST['param_name'];
However, if an undefined param is specified, it will result in an warning and ruin your output, if you manually parse it */
$user = GetRequestParam(1);
$pass = GetRequestParam(2);
/* GetRequestParam returns 'INVALID_PARAMETER' instead of a warning that an undefined param was requested */
$invalid_param = GetRequestParam(42);
/* Re-hash password with a salt that's stored in the PHP file only, before using or comparing it to the value stored in database or doing whatever else */
$salt = $user . $pass . "secretkey42";
$salt_hashed_passsword = strtoupper(hash('sha256', $salt));
echo "User: $user";
echo "\nHashed Password: $salt_hashed_passsword (Salt)";
}
?>
Edit: I could use HTTP header, but isn't it possible to reverse my application and abuse it?
Edit: I currently decided to use HTTP authentication as a temporary measure.
I stored a random generated username and password in my PHP file and compare them to the PHP_AUTH_USER/PW which are sent in the HTTP header from my cpp application using CURLOPT_USERPWD:
curl_easy_setopt(curl, CURLOPT_USERPWD, "randomhttpusername:randomhttppassword");
Hopefully, this will at least make it a bit harder for the hacker. First he will have to RE my application to get the the user/password and even after that he can only query the response if password belongs to specified user or not - since most of my queries are hard coded. You could even store the number of failed logins and temporarily ban him for x amount of time. Rest of the queries are made after login returns true.
I've also updated the code above to use the changes I've made and added some comments if you're too lazy to go over the code line-by-line. Feel free to give me some tips on how to improve the code or optimize for better use.

Answer 1

From what I understood, you want to implement a some sort of login system using auth tokens. In this case, OAuth can do the job. Here's a tutorial written on SitePoint that can guide you through the process.