Deleting a file(s) from server PHP - Permission denied unlink

Question

I want to delete files from my local server that's running on my beaglebone.

I have created a page that displays all the files and lets you select the files to delete. (As you can see below)

The webpage returns the names of the files to delete in the form of an array to the php script unlink.php

The code for Unlink.php is:

<?php

$files = $_POST['file'];

print_r($files);

if (empty($files)) {
    echo "No files were selected. Go back to 192.168.7.2 and refresh the page." ;
} else {
    $N = count($files);
    for ($i = 0; $i < $N; $i++) {
        $path = '/Logs/';
        print_r($path);
        #chown($path, 666);
        if (unlink($path . $_GET['$files[$i]'])) {
            echo ": Deleted";
        } else {
            echo "fail";
        }
    }
}
?>

However, whenever I try to delete a file: It fails.

The unlink() php function isn't being implemented properly and I'm not sure why. How do I do this the right way?

The index.html page is located in /var/www/html and the logs are located in /var/www/html/Logs/. The address of the local server is 192.168.7.2

Form code:

<?php

$url = $_SERVER['DOCUMENT_ROOT'];
$path = "/var/www/html/Logs";
$dh = opendir($path);
$k = 0;
$foo = True;

while (($file = readdir($dh)) !== false) {
    
    if ($file != "." && $file != "..") {
        
        if ($k == 0 || $k % 6 == 0) {
            $col .= "<tr><td><input type='checkbox' name='file[]' value='$file'>  <a href='Logs/$file'>$file</a><br /></td>";
        } else if ($k % 6 == 5) {
            $col .= "<td><input type='checkbox' name='file[]' value='$file'>  <a href='Logs/$file'>$file</a><br /></td></tr>";
        } else {
            $col .= "<td><input type='checkbox' name='file[]' value='$file'>  <a href='Logs/$file'>$file</a><br /></td>";
        }

        $k++;
    }
}
echo "<form action='unlink.php' method='post'><table>$col</table><br/><center><input type='submit' name='formSubmit' value='Delete' /></center></form>";

closedir($dh);
?> 

EDIT: PHP display-errors

Warning: chmod(): Operation not permitted in /var/www/html/unlink.php on line 17 chmod($path . $files[$i], 0755);

Warning: unlink(/var/www/html/Logs/2017.01.24--13.43.43--0.log): Permission denied in /var/www/html/unlink.php on line 18 fail if (unlink($path . $files[$i]))

but when I check ls -la for /Logs -> it shows up as it belongs to www-data. How do I change the permissions beyond this?

Permissions:

Answer 1

<?php

$files = $_POST['file'];
$path = "/var/www/html/Logs/";
print_r($files);

if (empty($files)) {
    echo "No files were selected. Go back to 192.168.7.2 and refresh the page." ;
} else {
    foreach ($files as $file) {
        if (unlink($path . $file)) {
            echo $path. $file ." : Deleted";
        } else {
            echo $path. $file . " : fail";
        }
    }
}
?>

That should do it, $path was wrong, and even if you had used the same as in the other code, it was missing a slash. Nonetheless this code is not going to prevent malicious user actions. How to avoid UNLINK security risks in PHP?

From your updated question I can see that the Logs folder is a symlink to /media/card/Logs. What is the output of ls -la /media/card?

Some further reads:

• https://en.wikipedia.org/wiki/Symbolic_link
• http://php.net/manual/en/control-structures.foreach.php

Answer 2

1. Make sure the file that you are trying to pass to unlink() / delete is not being opened. If the file is .exe or etc please also check in Windows Task Manager -> Process and then kill it.
2. Change permission status of file. Maybe you can't have access to delete the file (execute permission).

After you sure the file is not being opened 1, then lets try this code :

// Check existence of file
if (file_exists($cekFile1)) {
    // make sure you have permission to delete file
    if(chmod($fileDir, 0777)){
        if(!unlink($cekFile1)){
            echo "unlink is fail !";
        }
    }else{
        echo "chmod is fail";
    }
    // owner have read, write, execute rights.
    // owner's user group only have read rights.
    // everybody else only have read rights.
    chmod($fileDir, 0744);

}

For more information about chmod(), please check this reference:

php.net.

php-cmod-function.