a9f38acbf2
daemon/gvfsdaemon.c in gvfsd from GNOME gvfs before 1.38.3, 1.40.x before 1.40.2, and 1.41.x before 1.41.3 opened a private D-Bus server socket without configuring an authorization rule. A local attacker could connect to this server socket and issue D-Bus method calls. (Note that the server socket only accepts a single connection, so the attacker would have to discover the server and connect to the socket before its owner does.) Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com> Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
97 lines
3.4 KiB
Diff
97 lines
3.4 KiB
Diff
From 70dbfc68a79faac49bd3423e079cb6902522082a Mon Sep 17 00:00:00 2001
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From: Simon McVittie <smcv@collabora.com>
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Date: Wed, 5 Jun 2019 13:33:38 +0100
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Subject: [PATCH] gvfsdaemon: Check that the connecting client is the same user
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Otherwise, an attacker who learns the abstract socket address from
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netstat(8) or similar could connect to it and issue D-Bus method
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calls.
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Signed-off-by: Simon McVittie <smcv@collabora.com>
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[Retrieved from:
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https://gitlab.gnome.org/GNOME/gvfs/commit/70dbfc68a79faac49bd3423e079cb6902522082a]
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Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
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---
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daemon/gvfsdaemon.c | 36 +++++++++++++++++++++++++++++++++++-
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1 file changed, 35 insertions(+), 1 deletion(-)
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diff --git a/daemon/gvfsdaemon.c b/daemon/gvfsdaemon.c
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index 406d4f8e..be148a7b 100644
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--- a/daemon/gvfsdaemon.c
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+++ b/daemon/gvfsdaemon.c
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@@ -79,6 +79,7 @@ struct _GVfsDaemon
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gint mount_counter;
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+ GDBusAuthObserver *auth_observer;
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GDBusConnection *conn;
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GVfsDBusDaemon *daemon_skeleton;
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GVfsDBusMountable *mountable_skeleton;
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@@ -171,6 +172,8 @@ g_vfs_daemon_finalize (GObject *object)
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}
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if (daemon->conn != NULL)
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g_object_unref (daemon->conn);
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+ if (daemon->auth_observer != NULL)
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+ g_object_unref (daemon->auth_observer);
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g_hash_table_destroy (daemon->registered_paths);
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g_hash_table_destroy (daemon->client_connections);
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@@ -236,6 +239,35 @@ name_vanished_handler (GDBusConnection *connection,
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daemon->lost_main_daemon = TRUE;
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}
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+/*
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+ * Authentication observer signal handler that authorizes connections
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+ * from the same uid as this process. This matches the behaviour of a
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+ * libdbus DBusServer/DBusConnection when no DBusAllowUnixUserFunction
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+ * has been set, but is not the default in GDBus.
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+ */
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+static gboolean
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+authorize_authenticated_peer_cb (GDBusAuthObserver *observer,
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+ G_GNUC_UNUSED GIOStream *stream,
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+ GCredentials *credentials,
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+ G_GNUC_UNUSED gpointer user_data)
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+{
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+ gboolean authorized = FALSE;
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+
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+ if (credentials != NULL)
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+ {
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+ GCredentials *own_credentials;
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+
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+ own_credentials = g_credentials_new ();
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+
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+ if (g_credentials_is_same_user (credentials, own_credentials, NULL))
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+ authorized = TRUE;
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+
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+ g_object_unref (own_credentials);
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+ }
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+
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+ return authorized;
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+}
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+
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static void
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g_vfs_daemon_init (GVfsDaemon *daemon)
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{
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@@ -265,6 +297,8 @@ g_vfs_daemon_init (GVfsDaemon *daemon)
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daemon->conn = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, NULL);
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g_assert (daemon->conn != NULL);
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+ daemon->auth_observer = g_dbus_auth_observer_new ();
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+ g_signal_connect (daemon->auth_observer, "authorize-authenticated-peer", G_CALLBACK (authorize_authenticated_peer_cb), NULL);
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daemon->daemon_skeleton = gvfs_dbus_daemon_skeleton_new ();
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g_signal_connect (daemon->daemon_skeleton, "handle-get-connection", G_CALLBACK (handle_get_connection), daemon);
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@@ -876,7 +910,7 @@ handle_get_connection (GVfsDBusDaemon *object,
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server = g_dbus_server_new_sync (address1,
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G_DBUS_SERVER_FLAGS_NONE,
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guid,
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- NULL, /* GDBusAuthObserver */
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+ daemon->auth_observer,
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NULL, /* GCancellable */
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&error);
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g_free (guid);
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--
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2.24.1
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