#3885 (ok 4.1.4) display_binary_as_hex option causes unexpected behavior

[Tim Fennis]

A while ago my colleague submitted a patch that introduced the display_binary_as_hex option. The patch was accepted by the PhpMyAdmin dev team. It seems though that at some point changes have been made to the source code that introduce a bug that causes binary values to not be displayed correctly.

// Current source found in DisplayResults.class.php @ line 3900 (4.0.0)
if ($_SESSION['tmp_user_values']['display_binary_as_hex']
     && PMA_Util::containsNonPrintableAscii($column)
) {
    $column = bin2hex($column);
} else {
    $column = htmlspecialchars(
        PMA_Util::replaceBinaryContents(
            $column
        )
    );
}

The origional version never included the added PMA_Util::containsNonPrintableAscii($column) check. If the user enabled the display_binary_as_hex option than you NEVER want to show the binary data anyways (just because it's supposed to be printable).

But it gets even worse. It turns out about 10% of my UUID's pass the PMA_Util::containsNonPrintableAscii($column) check. But when this UUID is passed to the htmlspecialchars function all the data gets deleted because the function is unable to convert the binary data to HTML special chars.

I have 2 propositions:

1. If the user has the display_binary_as_hex option set, then ALWAYS display the value as is
2. If the option is disabled than use PHP's latest htmlspecialchars update to show the non-printable characters as block as described in this article.

for some reason a list cannot be followed by code on sourceforge

if ($_SESSION['tmp_user_values']['display_binary_as_hex']) {
    $column = bin2hex($column);
} else {
    $column = htmlspecialchars(
        PMA_Util::replaceBinaryContents(
            $column,
            ENT_SUBSTITUTE //Only works in PHP 5.4
        )
    );
}

Note: We believe a plausible reason for the introduction of this bug is that htmlspecialchars behavior has changed. I cannot find any evidence for this but we believe the origional behavior ignored invalid characters.

[Laurent DELAGE]

Seems that this patch cause another problem.

On milestone 4.0.1, php5.3, when a column is set to collate utf8-bin, data is always displayed as hexadecimal, whatever the value of display_binary_as_hex is.

Looking at libraries/DisplayResults.class.php, line 5941, if php version is < 5.4, then bin2hex is called every time.

The check is done because of no existence of ENT_SUBSTITUTE in 5.3, but i think a call without this constant is better than inconditionnel call to bin2hex.

[Marc Delisle]

Tim,
can you show me your table's structure and tell me on which PHP version you are?

[Marc Delisle]

Laurent and Tim,
can you have a look at
https://github.com/phpmyadmin/phpmyadmin/commit/157154f20d590ebc6090fad9854921540abff42d
intended for the upcoming 4.1.4 version?