51.beta
=======

* Fixed autologin bypass where a compromised greeter could request autologin
  for any local account by sending arbitrary usernames via BeginAutoLogin
* Dropped unused `enable-web-authentication` and `enable-passkey-authentication`
  gsettings keys from the `org.gnome.login-screen` schema
* Introduced PAM substack safety net, such that authentication cannot by bypassed
  on systems where authselect hasn't configured a PAM service file for a specific
  authentication method (i.e. `gdm-switchable-auth`)
* Fixed double-free in session worker
* Reworked build script for installing PAM service files into modern search path
* Redid PAM service loading logic in GDM, to introduce meaningful error messages
  whenever PAM services aren't found
* Fixed memory leaks in PAM extensions
* Fixed denial of service where an invalid session name from the greeter would
  cause the entire daemon to exit, terminating all active sessions
* Adjusted D-Bus object path generation for /org/gnome/DisplayManager/Displays/*
  to fix ASLR leak
* Fixed input sanitation when forwarding unknown usernames to audit subsystem
* Fixed passphrase handling in pam_gdm to wipe cached plaintext passwords
  before freeing and to bound the keyring buffer walk preventing out-of-bounds
  reads
* Fixed path traversal vulnerability where a compromised greeter could load
  arbitrary .desktop files via SelectSession, potentially executing
  attacker-controlled commands as the authenticated user
* Introduced $GDM_AUTH_SESSION_ID environment variable, which communicates the
  logind session ID of the caller that requested authentication. This will be used
  for smartcard redirection for remote sessions