C#•2y ago

✅ Need some help converting PHP code to CS

Hey, I think I wrote this right but I'm getting different results. Perhaps someone knows what I did wrong here? I'm trying to convert a PHP function to a C# function. Here is what I wrote in C#. The original PHP snippets are the comments above.

string tobase64str(string input, int count)
{
    string output = "";
    int i = 0;
    string itoa64 = _password_itoa64();
    do
    {
        //string value = ord($input[$i++]);
        var value = input[i++];
        //$output.= $itoa64[$value & 0x3f];
        output += itoa64[value & 0x3f];
        //if ($i < $count) {
        if (i < count)
        {
            //$value |= ord($input[$i]) << 8;
            value = ((char)(value | input[i] << 8));
        }
        //$output.= $itoa64[($value >> 6) & 0x3f];
        output += itoa64[(value >> 6) & 0x3f];
        //if ($i++ >= $count) {
        if (i++ >= count)
        {
            break;
        }
        //if ($i < $count) {
        if (i < count)
        {
            //$value |= ord($input[$i]) << 16;
            value = (char)(value | input[i] << 16);
        }
        //$output.= $itoa64[($value >> 12) & 0x3f];
        output += itoa64[(value >> 12) & 0x3f];
        //if ($i++ >= $count) {
        if (i++ >= count)
        {
            break;
        }
        //$output.= $itoa64[($value >> 18) & 0x3f];
        output += itoa64[(value >> 18) & 0x3f];
    } while (i < count);

    return output;
}

string _password_itoa64()
{
    return "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
}

string tobase64str(string input, int count)
{
    string output = "";
    int i = 0;
    string itoa64 = _password_itoa64();
    do
    {
        //string value = ord($input[$i++]);
        var value = input[i++];
        //$output.= $itoa64[$value & 0x3f];
        output += itoa64[value & 0x3f];
        //if ($i < $count) {
        if (i < count)
        {
            //$value |= ord($input[$i]) << 8;
            value = ((char)(value | input[i] << 8));
        }
        //$output.= $itoa64[($value >> 6) & 0x3f];
        output += itoa64[(value >> 6) & 0x3f];
        //if ($i++ >= $count) {
        if (i++ >= count)
        {
            break;
        }
        //if ($i < $count) {
        if (i < count)
        {
            //$value |= ord($input[$i]) << 16;
            value = (char)(value | input[i] << 16);
        }
        //$output.= $itoa64[($value >> 12) & 0x3f];
        output += itoa64[(value >> 12) & 0x3f];
        //if ($i++ >= $count) {
        if (i++ >= count)
        {
            break;
        }
        //$output.= $itoa64[($value >> 18) & 0x3f];
        output += itoa64[(value >> 18) & 0x3f];
    } while (i < count);

    return output;
}

string _password_itoa64()
{
    return "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
}

Upon running this, I do not get the expected result of: VrOlH8EFHZWQeyrP2on5MR7Q8QMC08ZnHfLv8UE54ZwL7CIJ6vKhT3EpdYriab.oA/yv9wP/yyWUHQC9.18y0$S$D Instead, I get: /..l1..F1..Q0..P...5...Q0..C0..n1..v0..50..L/..J...h1..p/..i0..o...v1../0..U1..9...y0

23 Replies

TerryDevOP•2y ago

just in case, here is the original PHP function in full:

function _password_itoa64() {
  return './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
}

/**
 * Encodes bytes into printable base 64 using the *nix standard from crypt().
 *
 * @param $input
 *   The string containing bytes to encode.
 * @param $count
 *   The number of characters (bytes) to encode.
 *
 * @return
 *   Encoded string
 */
function _password_base64_encode($input, $count) {
  $output = '';
  $i = 0;
  $itoa64 = _password_itoa64();
  do {
    $value = ord($input[$i++]);
    $output .= $itoa64[$value & 0x3f];
    if ($i < $count) {
      $value |= ord($input[$i]) << 8;
    }
    $output .= $itoa64[($value >> 6) & 0x3f];
    if ($i++ >= $count) {
      break;
    }
    if ($i < $count) {
      $value |= ord($input[$i]) << 16;
    }
    $output .= $itoa64[($value >> 12) & 0x3f];
    if ($i++ >= $count) {
      break;
    }
    $output .= $itoa64[($value >> 18) & 0x3f];
  } while ($i < $count);

  return $output;
}

function _password_itoa64() {
  return './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
}

/**
 * Encodes bytes into printable base 64 using the *nix standard from crypt().
 *
 * @param $input
 *   The string containing bytes to encode.
 * @param $count
 *   The number of characters (bytes) to encode.
 *
 * @return
 *   Encoded string
 */
function _password_base64_encode($input, $count) {
  $output = '';
  $i = 0;
  $itoa64 = _password_itoa64();
  do {
    $value = ord($input[$i++]);
    $output .= $itoa64[$value & 0x3f];
    if ($i < $count) {
      $value |= ord($input[$i]) << 8;
    }
    $output .= $itoa64[($value >> 6) & 0x3f];
    if ($i++ >= $count) {
      break;
    }
    if ($i < $count) {
      $value |= ord($input[$i]) << 16;
    }
    $output .= $itoa64[($value >> 12) & 0x3f];
    if ($i++ >= $count) {
      break;
    }
    $output .= $itoa64[($value >> 18) & 0x3f];
  } while ($i < $count);

  return $output;
}

Angius•2y ago

C# just has Convert.ToBase64() method if you need to encode stuff to base64

TerryDevOP•2y ago

I’ve attempted to use that, however whatever weird function drupal uses to hash it’s passwords outputs something completely different from a regular base64 conversion. Using Convert.ToBase64 and phps built in Base64 encoder produce the exact same string on the input, but unfortunately I need the C# program to output the Base64 string that’s encoded through this method

Angius•2y ago

Why does Drupal use some weird base64 encoding to hash passwords instead of an established algorithm 💀 That's a security nightmare Let me look into it, maybe they are using some existing algo, just named it weirdly

TerryDevOP•2y ago

Drupal fucking sucks, which is why I’m trying to move away from it and just build everything from scratch haha

Angius•2y ago

Only thing I found so far is this: https://www.drupal.org/forum/support/module-development-and-code-questions/2014-07-04/_password_base64_encode

TerryDevOP•2y ago

Perhaps the comment at the top of the PHP function above might ring some bells for you? I’m completely lost when it comes to this stuff unfortunately. I appreciate your help Ah yes the classic “just use something else” hahahah

Angius•2y ago

Okay, so, apparently... Drupal uses some weird shit instead of the built-in password_hash() function of PHP It returns bytes, that need to be encoded as base64 And this method is supposed to do that Which... doesn't answer the original issue, but at least it's a clue to the weirdness lol

TerryDevOP•2y ago

Yup I’ve successfully written the password hashing function in C#, and verified that it’s hashing the passwords correctly. The last piece of the puzzle is converting the hash byte array to the weird string it stores in the database

Angius•2y ago

It also uses some ord() function to get integer value of a char...

value = ((char)(value | input[i] << 8));

value = ((char)(value | input[i] << 8));

$value |= ord($input[$i]) << 8;

$value |= ord($input[$i]) << 8;

Let's make them more alike

TerryDevOP•2y ago

ord() function is a inbuilt function in PHP that returns the ASCII value of the first character of a string Hmmmm

Angius•2y ago

value =| input[i] << 8;

value =| input[i] << 8;

$value |= ord($input[$i]) << 8;

$value |= ord($input[$i]) << 8;

TerryDevOP•2y ago

Wait does c# have the =| operator?

Angius•2y ago

yeah

Angius•2y ago

Angius•2y ago

Aight, we know that ord('a') is equivalent to (int)'a' So

$value |= ord($input[$i]) << 8;

$value |= ord($input[$i]) << 8;

can be

value |= (int)input[i] << 8;

value |= (int)input[i] << 8;

TerryDevOP•2y ago

oh my god yup that did it

Angius•2y ago

'Ere we go lol

TerryDevOP•2y ago

thank you so much for your help!

Angius•2y ago

Anytime

TerryDevOP•2y ago

time to ditch drupal forever hahah

Angius•2y ago

I heard newer versions aren't that bad They're based on Symfony components, use Twig for templating, etc

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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✅ Need some help converting PHP code to CS