nm-ip-config: escape searches when exposing to dbus

Previously, when a connection was configured with search domains
that contained non-ASCII characters, GLib would try to parse the
search name as UTF-8, and an assertion would fail (which meant
that if NM was running with fatal assertions, it would crash).

Expose the search domains only as an escaped string to avoid this.

src/core/nm-ip-config.c

@@ -162,6 +162,7 @@ get_property_ip(GObject *object, guint prop_id, GValue *value, GParamSpec *pspec
     NMIPConfig        *self        = NM_IP_CONFIG(object);
     NMIPConfigPrivate *priv        = NM_IP_CONFIG_GET_PRIVATE(self);
     const int          addr_family = nm_ip_config_get_addr_family(self);
+    char             **to_free     = NULL;
     char               sbuf_addr[NM_INET_ADDRSTRLEN];
     const char *const *strv;
     guint              len;
@@ -193,7 +194,20 @@ get_property_ip(GObject *object, guint prop_id, GValue *value, GParamSpec *pspec
         break;
     case PROP_IP_SEARCHES:
         strv = nm_l3_config_data_get_searches(priv->l3cd, addr_family, &len);
+        if (strv) {
+            strv = nm_utils_buf_utf8safe_escape_strv(
+                strv,
+                -1,
+                NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL
+                    | NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_NON_ASCII,
+                &to_free);
+        }
+
         _value_set_variant_as(value, strv, len);
+
+        if (to_free) {
+            g_strfreev(to_free);
+        }
         break;
     case PROP_IP_DNS_PRIORITY:
         v_i = nm_l3_config_data_get_dns_priority_or_default(priv->l3cd, addr_family);