Simple PHP Authorization (login/pass)

Login form and authorization (hashed login/pass) for single PHP files

Features

• Time out after a customizable period $time_out (defaults to 15 minutes)
• Allow multiple logins in hashed $credentials array (defaults to "admin" and "password")
• Add custom $salt (defaults to none)
• Set a maximum number of failed login attempts via $max_logins (default 5)
• Set a minimum number of hours before a user may retry logging in after exceeding the maximum failed logins via $ban_time (defaults to 24). This is not super secure, since using a different computer/clearing cookies would allow retrying the login anyway. A better way (not implemented) would be to store the usernames that were tried (if they exist) on the server (in a text file for example) and block those. Or interface to fail2ban and block the IP. Also, it would be better to silently reject logins after banning (even if correct), instead of displaying a notice indicating that there was a ban.
• Set a maximum login time (even if there is activity) via $max (defaults to 86400 seconds/one day)
• Log out using ?logout in the url

Caveats

• You will need to implement your own method to log people out after inactivity; the script does not handle this proactively. This means that if a user session times out, the page content that may remain displayed to the user (on their browser) would still be present (auto-logout would only be triggered when they manually navigate or reload the page.
• Obviously storing credentials in a script is not a good practice, but I don't care. You need to accept that this is not the purpose of this program. This is a quick and dirty way to provide authentication, and it is left entirely to the user to change these values on a each installation, not to commit running values to a repository, or to implement a more versatile solution (for example, via ENV or other secure variable store outside of the script itself).
• SHA256 is outdated. Again, I don't care. The user can change the hashing algorithm and add salt or pepper or whatever lets them sleep at night.
• Mostly I don't think anyone uses this so it's not important to me to make it more versatile than it currently is. Create a ticket in the issue tracker if you have any suggestions or would like to see some of these improvements implemented.

Usage

include '/path/to/auth.php'; in your script. Make sure you modify the $credentials array and other optionally customizable parameters to store sha256 hashes of your username/passwords. To generate a sha256 hash of a string in bash, use echo $(echo -n "texttohash" | sha256sum | cut -d " " -f1)