device: ppp: start stage3 only after we receive IP configuration

The pppd plugin first sends a phase change signal to RUNNING and then
sends IPv4 and IPv6 configurations. NM knows the actual interface name
(and thus populates the ifindex) only after an IP configuration is
received from the plugin.

If we start configuring IPv4 and IPv6 as soon as the PPP status is
RUNNING, it is possible to hit an assertion because
activate_stage3_ip_config_start() tries to capture the current IPv6
configuration when the device ifindex is not known yet.

Instead, let's start configuring IP only after the ifindex is known.

https://bugzilla.redhat.com/show_bug.cgi?id=1515829

1 files changed, 29 insertions, 22 deletions

diff --git a/src/devices/nm-device-ppp.c b/src/devices/nm-device-ppp.c
index 6de236be70..a8ae7e309d 100644
--- a/src/devices/nm-device-ppp.c
+++ b/src/devices/nm-device-ppp.c
@@ -88,9 +88,6 @@ ppp_state_changed (NMPPPManager *ppp_manager, NMPPPStatus status, gpointer user_
 	case NM_PPP_STATUS_DEAD:
 		nm_device_state_changed (device, NM_DEVICE_STATE_FAILED, NM_DEVICE_STATE_REASON_PPP_FAILED);
 		break;
-	case NM_PPP_STATUS_RUNNING:
-		nm_device_activate_schedule_stage3_ip_config_start (device);
-		break;
 	default:
 		break;
 	}
@@ -111,23 +108,36 @@ ppp_ip4_config (NMPPPManager *ppp_manager,
 
 	if (nm_device_get_state (device) == NM_DEVICE_STATE_IP_CONFIG) {
 		if (nm_device_activate_ip4_state_in_conf (device)) {
-			if (!nm_device_take_over_link (device, iface, &renamed)) {
-				nm_device_state_changed (device, NM_DEVICE_STATE_FAILED,
-				                         NM_DEVICE_STATE_REASON_IP_CONFIG_UNAVAILABLE);
-				return;
-			}
-			if (renamed)
-				nm_manager_remove_device (nm_manager_get (), iface, NM_DEVICE_TYPE_PPP);
-
 			nm_device_activate_schedule_ip4_config_result (device, config);
-			return;
 		}
-	} else {
-		if (priv->ip4_config)
-			g_object_unref (priv->ip4_config);
-		priv->ip4_config = g_object_ref (config);
-		g_free (priv->iface);
+		return;
+	}
+
+	/* We are not yet in the IP configuration stage: cache the
+	 * configuration for later.
+	 */
+	if (priv->ip4_config)
+		g_object_unref (priv->ip4_config);
+	priv->ip4_config = g_object_ref (config);
+
+	if (priv->iface)
+		g_assert_cmpstr (priv->iface, ==, iface);
+	else {
+		/* Complete device initialization when we receive the first
+		 * IP{4,6} configuration and we know the name of the interface
+		 * created by pppd.
+		 */
 		priv->iface = g_strdup (iface);
+		if (!nm_device_take_over_link (device, iface, &renamed)) {
+			nm_device_state_changed (device, NM_DEVICE_STATE_FAILED,
+			                         NM_DEVICE_STATE_REASON_IP_CONFIG_UNAVAILABLE);
+			return;
+		}
+		if (renamed)
+			nm_manager_remove_device (nm_manager_get (), iface, NM_DEVICE_TYPE_PPP);
+
+		/* Once the device gets an ifindex, start with IP configuration */
+		nm_device_activate_schedule_stage3_ip_config_start (device);
 	}
 }
 
@@ -189,13 +199,10 @@ act_stage3_ip4_config_start (NMDevice *device,
 {
 	NMDevicePpp *self = NM_DEVICE_PPP (device);
 	NMDevicePppPrivate *priv = NM_DEVICE_PPP_GET_PRIVATE (self);
-	gboolean renamed;
+
+	_LOGT (LOGD_DEVICE | LOGD_PPP, "ip4 config start");
 
 	if (priv->ip4_config) {
-		if  (!nm_device_take_over_link (device, priv->iface, &renamed))
-			return NM_ACT_STAGE_RETURN_FAILURE;
-		if (renamed)
-			nm_manager_remove_device (nm_manager_get (), priv->iface, NM_DEVICE_TYPE_PPP);
 		if (out_config)
 			*out_config = g_steal_pointer (&priv->ip4_config);
 		else