Add support for usage banner for NIST 800-53 compliance.

README.md

@@ -19,6 +19,7 @@ A configuration tool is available at https://github.com/linuxmint/lightdm-settin
 - This greeter supports HiDPI.
 - Sessions are validated. If a default/chosen session isn't present on the system, the greeter scans for known sessions in /usr/share/xsessions and replaces the invalid session choice with a valid session.
 - You can take a screenshot by pressing PrintScrn. The screenshot is saved in /var/lib/lightdm/Screenshot.png.
+- A **banner/acceptance dialog** can be shown before login. When enabled, the user must read and accept a policy notice before proceeding. The dialog reads its text from `/etc/issue` by default, or from a custom file specified in the configuration.
 
 # Credit
 
@@ -62,4 +63,6 @@ Configuration file format for /etc/lightdm/slick-greeter.conf
     # only-on-monitor=Sets the monitor on which to show the login window, -1 means "follow the mouse"
     # stretch-background-across-monitors=Whether to stretch the background across multiple monitors (false by default)
     # clock-format=What clock format to use (e.g., %H:%M or %l:%M %p)
+    # show-banner=Whether to show a banner/acceptance dialog before login (true or false)
+    # banner-file=Path to the file whose contents are shown in the banner dialog (defaults to /etc/issue)
 

data/x.dm.slick-greeter.gschema.xml

@@ -160,5 +160,14 @@
       <default>'left'</default>
       <summary>Alignment of the main content</summary>
     </key>
+    <key name="show-banner" type="b">
+      <default>false</default>
+      <summary>Whether to show a usage-policy banner from /etc/issue before login</summary>
+      <description>When enabled the greeter reads the file specified by banner-file (default /etc/issue) and displays its contents in a dialog. The user must click "I Accept" before the login UI is enabled.</description>
+    </key>
+    <key name="banner-file" type="s">
+      <default>''</default>
+      <summary>Path to the banner file shown before login (default: /etc/issue)</summary>
+    </key>
   </schema>
 </schemalist>

debian/install

@@ -1 +1,2 @@
 debian/90-slick-greeter.conf /usr/share/lightdm/lightdm.conf.d/
+debian/slick-greeter.conf /etc/lightdm/

debian/slick-greeter.conf

@@ -0,0 +1,118 @@
+[Greeter]
+# Background image path (leave blank for none)
+#background=
+
+# Background color when no image is set
+#background-color=#000000
+
+# Stretch background across all monitors
+#stretch-background-across-monitors=false
+
+# Draw per-user backgrounds
+#draw-user-backgrounds=true
+
+# Draw the dot-grid overlay
+#draw-grid=false
+
+# Show the hostname in the menubar
+#show-hostname=true
+
+# Show the keyboard layout selector
+#show-keyboard=true
+
+# Show the accessibility menu
+#show-a11y=true
+
+# Show the power menu
+#show-power=true
+
+# Show the clock
+#show-clock=true
+
+# Show the quit/session-end button
+#show-quit=true
+
+# Path to a logo image shown in the greeter
+#logo=
+
+# Path to a logo image shown on secondary monitors
+#other-monitors-logo=
+
+# GTK theme name
+#theme-name=Adwaita
+
+# Icon theme name
+#icon-theme-name=gnome
+
+# Cursor theme name
+#cursor-theme-name=default
+
+# Cursor theme size
+#cursor-theme-size=24
+
+# Font name and size
+#font-name=Ubuntu 11
+
+# Enable font antialiasing
+#xft-antialias=true
+
+# Font DPI
+#xft-dpi=96
+
+# Font hint style (none, slight, medium, full)
+#xft-hintstyle=
+
+# Font subpixel rendering (none, rgb, bgr, vrgb, vbgr)
+#xft-rgba=
+
+# Enable the on-screen keyboard by default
+#onscreen-keyboard=false
+
+# Path to the on-screen keyboard layout file
+#onscreen-keyboard-layout=/usr/share/onboard/layouts/Small.onboard
+
+# Enable high-contrast mode by default
+#high-contrast=false
+
+# Enable the screen reader by default
+#screen-reader=false
+
+# Path to a sound file to play when the greeter is ready (leave blank for none)
+#play-ready-sound=
+
+# Space-separated list of usernames to hide from the user list
+#hidden-users=
+
+# Only show users belonging to this group (leave blank for all users)
+#group-filter=
+
+# HiDPI mode: auto, on, or off
+#enable-hidpi=auto
+
+# Activate Num Lock on startup
+#activate-numlock=false
+
+# Only show the greeter on this monitor (e.g. "0", "HDMI-1"); "auto" uses the primary
+#only-on-monitor=auto
+
+# Clock format string (strftime syntax)
+#clock-format=%H:%M
+
+# Horizontal alignment of the login panel: left, center, right
+#content-align=
+
+# ── System Use Notification (login banner) ──────────────────────────────────
+#
+# When show-banner is true the greeter displays the contents of banner-file
+# in a dialog before the login UI is shown.  The user must click "I Accept"
+# to proceed.  This satisfies the DoD / NIST SP 800-53 AC-8 requirement for
+# a system-use notification at login time.
+#
+# To enable:
+#   1. Set show-banner to true.
+#   2. Set banner-file to the path of your notification text (plain text).
+#      Defaults to /etc/issue when left blank.
+#   3. Edit that file with your approved system-use notification wording.
+#
+#show-banner=false
+#banner-file=/etc/issue

po/POTFILES.in

@@ -2,6 +2,8 @@
 # Please keep this file sorted alphabetically.
 src/animate-timer.vala
 src/background.vala
+src/banner-dialog.vala
+src/banner-dialog.vala
 src/cached-image.vala
 src/dash-box.vala
 src/dash-button.vala

slick-greeter.pot

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2023-06-01 11:07+0100\n"
+"POT-Creation-Date: 2026-02-27 10:00-0600\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -17,88 +17,105 @@ msgstr ""
 "Content-Type: text/plain; charset=CHARSET\n"
 "Content-Transfer-Encoding: 8bit\n"
 
-#: src/greeter-list.vala:303
+#: src/banner-dialog.vala:81
+msgid "System Notice"
+msgstr ""
+
+#: src/banner-dialog.vala:90
+msgid "You must read and accept the following policy before logging in:"
+msgstr ""
+
+#: src/banner-dialog.vala:142
+msgid "I Accept"
+msgstr ""
+
+#. Translators: shown when the banner file cannot be read
+#: src/banner-dialog.vala:175
+msgid "(Could not read the login banner file.)"
+msgstr ""
+
+#: src/greeter-list.vala:307
 #, c-format
 msgid "Enter password for %s"
 msgstr ""
 
-#: src/greeter-list.vala:305
+#: src/greeter-list.vala:309
 msgid "Enter your username"
 msgstr ""
 
-#: src/greeter-list.vala:815 src/user-list.vala:720
+#: src/greeter-list.vala:819 src/user-list.vala:720
 msgid "Password:"
 msgstr ""
 
-#: src/greeter-list.vala:817 src/user-list.vala:714
+#: src/greeter-list.vala:821 src/user-list.vala:714
 msgid "Username:"
 msgstr ""
 
-#: src/greeter-list.vala:872
+#: src/greeter-list.vala:877
 msgid "Invalid password, please try again"
 msgstr ""
 
-#: src/greeter-list.vala:883
+#: src/greeter-list.vala:888
 msgid "Failed to authenticate"
 msgstr ""
 
-#: src/greeter-list.vala:929
+#: src/greeter-list.vala:934
 msgid "Failed to start session"
 msgstr ""
 
-#: src/greeter-list.vala:943
+#: src/greeter-list.vala:948
 msgid "Logging in..."
 msgstr ""
 
-#: src/main-window.vala:52
+#: src/main-window.vala:54
 msgid "Login Screen"
 msgstr ""
 
-#: src/main-window.vala:113
+#: src/main-window.vala:143
 msgid "Back"
 msgstr ""
 
-#: src/menubar.vala:324
+#: src/menubar.vala:372
 msgid "Power:"
 msgstr ""
 
-#: src/menubar.vala:374
+#: src/menubar.vala:437
 msgid "Accessibility"
 msgstr ""
 
-#: src/menubar.vala:383
+#: src/menubar.vala:446
 msgid "Onscreen keyboard"
 msgstr ""
 
-#: src/menubar.vala:388
+#: src/menubar.vala:451
 msgid "High Contrast"
 msgstr ""
 
-#: src/menubar.vala:394
+#: src/menubar.vala:457
 msgid "Screen Reader"
 msgstr ""
 
-#: src/menubar.vala:406 src/menubar.vala:453
+#: src/menubar.vala:469 src/menubar.vala:516
 msgid "Quit..."
 msgstr ""
 
-#: src/menubar.vala:419 src/shutdown-dialog.vala:155
+#: src/menubar.vala:482 src/shutdown-dialog.vala:155
 msgid "Suspend"
 msgstr ""
 
-#: src/menubar.vala:437 src/shutdown-dialog.vala:172
+#: src/menubar.vala:500 src/shutdown-dialog.vala:172
 msgid "Hibernate"
 msgstr ""
 
-#: src/menubar.vala:476 src/menubar.vala:520 src/menubar.vala:544
+#: src/menubar.vala:539 src/menubar.vala:583 src/menubar.vala:606
 msgid "Keyboard layout:"
 msgstr ""
 
-#: src/menubar.vala:532
+#: src/menubar.vala:595
 msgid "More layouts..."
 msgstr ""
 
-#: src/prompt-box.vala:215
+#: src/prompt-box.vala:250
 msgid "Session Options"
 msgstr ""
 
@@ -119,6 +136,7 @@ msgid "Are you sure you want to shut down the computer?"
 msgstr ""
 
 #: src/shutdown-dialog.vala:137
+#, c-format
 msgid ""
 "Other users are currently logged in to this computer, shutting down now will "
 "also close these other sessions."
@@ -128,24 +146,25 @@ msgstr ""
 msgid "Restart"
 msgstr ""
 
-#: src/slick-greeter.vala:749
+#. Translators: %s is a session name like KDE or Ubuntu
+#: src/toggle-box.vala:109
+#, c-format
+msgid "%s (Default)"
+msgstr ""
+
+#: src/slick-greeter.vala:770
 msgid "Show release version"
 msgstr ""
 
-#: src/slick-greeter.vala:752
+#: src/slick-greeter.vala:773
 msgid "Run in test mode"
 msgstr ""
 
-#: src/slick-greeter.vala:768
+#: src/slick-greeter.vala:789
 #, c-format
 msgid "Run '%s --help' to see a full list of available command line options."
 msgstr ""
 
-#: src/toggle-box.vala:109
-#, c-format
-msgid "%s (Default)"
-msgstr ""
-
 #: src/user-list.vala:45
 msgid "Guest Session"
 msgstr ""