From 9c8e6000783d09296ed2c02859a13489a15eb0d8 Mon Sep 17 00:00:00 2001
From: Dan Williams <dcbw@redhat.com>
Date: Thu, 2 Jul 2009 12:46:32 -0400
Subject: [PATCH] system-settings: let UID 0 bypass PolicyKit for PK < 1.0

PK < 1.0 doesn't work with UID 0 processes that aren't spawned via a
session-manager, and thus don't have the XDG_SESSION_COOKIE in their
environment (which ConsoleKit uses to figure out what session the
caller is in).  But since root could just scribble over the config
files anyway, bypassing PK for UID 0 doesn't meaningfully decrease
security.
---
 src/system-settings/nm-polkit-helpers.c | 38 ++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/src/system-settings/nm-polkit-helpers.c b/src/system-settings/nm-polkit-helpers.c
index 496a6f7ed1..638f2a8c14 100644
--- a/src/system-settings/nm-polkit-helpers.c
+++ b/src/system-settings/nm-polkit-helpers.c
@@ -98,14 +98,50 @@ check_polkit_privileges (DBusGConnection *dbus_connection,
 					DBusGMethodInvocation *context,
 					GError **err)
 {
+	DBusConnection *tmp;
 	DBusError dbus_error;
 	char *sender;
+	gulong sender_uid = G_MAXULONG;
 	PolKitCaller *pk_caller;
 	PolKitAction *pk_action;
 	PolKitResult pk_result;
 
-	dbus_error_init (&dbus_error);
+	/* Always allow uid 0 */
+	tmp = dbus_g_connection_get_connection (dbus_connection);
+	if (!tmp) {
+		g_set_error (err,
+		             NM_SYSCONFIG_SETTINGS_ERROR,
+		             NM_SYSCONFIG_SETTINGS_ERROR_GENERAL,
+		             "Could not get D-Bus connection.");
+		return FALSE;
+	}
+
 	sender = dbus_g_method_get_sender (context);
+
+	dbus_error_init (&dbus_error);
+	/* FIXME: do this async */
+	sender_uid = dbus_bus_get_unix_user (tmp, sender, &dbus_error);
+	if (dbus_error_is_set (&dbus_error)) {
+		g_set_error (err,
+		             NM_SYSCONFIG_SETTINGS_ERROR,
+		             NM_SYSCONFIG_SETTINGS_ERROR_GENERAL,
+		             "Could not determine the Unix user ID of the requestor: %s: %s",
+		             dbus_error.name, dbus_error.message);
+		dbus_error_free (&dbus_error);
+		return FALSE;
+	}
+
+	/* PolicyKit < 1.0 is not compatible with root processes spawned outside
+	 * the session manager, and when asking ConsoleKit for the session of the
+	 * process, ConsoleKit won't be able to get XDG_SESSION_COOKIE because it
+	 * doesn't exist in the caller's environment for non-session-managed
+	 * processes.  So, for PK < 1.0, ignore PolicyKit for uid 0.
+	 */
+	if (0 == sender_uid)
+		return TRUE;
+
+	/* Non-root users need to auth via PolicyKit */
+	dbus_error_init (&dbus_error);
 	pk_caller = polkit_caller_new_from_dbus_name (dbus_g_connection_get_connection (dbus_connection),
 										 sender,
 										 &dbus_error);