device: postpone updates of IP configuration when a commit is pending

When a new dynamic configuration is received, it is stored in a member
of private structure (e.g. @dhcp6_ip6_config) and a commit is
scheduled. Before the commit is executed, an update_ipx_config() could
be called and it would change the configuration before it is
committed.

This race condition causes failures in assigning the addresses
received through DHCPv6 when the internal client is used (but
potentially other clients and methods are affected).

To fix it, postpone updates of IP configurations when a commit is
already pending.

(cherry picked from commit a47c13a7a2cd66644adf2459690f9c3bb96235ab)

1 files changed, 33 insertions, 0 deletions

diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index dcdb027d69..692ffa7ba4 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -3382,6 +3382,15 @@ activation_source_schedule (NMDevice *self, ActivationHandleFunc func, int famil
 	act_data->id = new_id;
 }
 
+static gboolean
+activation_source_is_scheduled (NMDevice *self, ActivationHandleFunc func, int family)
+{
+	ActivationHandleData *act_data;
+
+	act_data = activation_source_get_by_family (self, family, NULL);
+	return act_data->func == func;
+}
+
 /*****************************************************************************/
 
 static gboolean
@@ -8779,6 +8788,18 @@ update_ip4_config (NMDevice *self, gboolean initial)
 	gboolean capture_resolv_conf;
 	NMDnsManagerResolvConfMode resolv_conf_mode;
 
+	/* If a commit is scheduled, this function would potentially interfere with
+	 * it changing IP configurations before they are applied. Postpone the
+	 * update in such case.
+	 */
+	if (activation_source_is_scheduled (self,
+	                                    activate_stage5_ip4_config_commit,
+	                                    AF_INET)) {
+		priv->queued_ip4_config_id = g_idle_add (queued_ip4_config_change, self);
+		_LOGT (LOGD_DEVICE, "IP4 update was postponed");
+		return;
+	}
+
 	ifindex = nm_device_get_ip_ifindex (self);
 	if (!ifindex)
 		return;
@@ -8857,6 +8878,18 @@ update_ip6_config (NMDevice *self, gboolean initial)
 	gboolean capture_resolv_conf;
 	NMDnsManagerResolvConfMode resolv_conf_mode;
 
+	/* If a commit is scheduled, this function would potentially interfere with
+	 * it changing IP configurations before they are applied. Postpone the
+	 * update in such case.
+	 */
+	if (activation_source_is_scheduled (self,
+	                                    activate_stage5_ip6_config_commit,
+	                                    AF_INET6)) {
+		priv->queued_ip6_config_id = g_idle_add (queued_ip6_config_change, self);
+		_LOGT (LOGD_DEVICE, "IP6 update was postponed");
+		return;
+	}
+
 	ifindex = nm_device_get_ip_ifindex (self);
 	if (!ifindex)
 		return;