From dd09af121bb2b078530497f47011ab632d4834eb Mon Sep 17 00:00:00 2001
From: Beniamino Galvani <bgalvani@redhat.com>
Date: Thu, 12 Dec 2024 11:00:07 +0100
Subject: [PATCH] dispatcher: fix serialization of DNS servers

In the "Action()" D-Bus method, the "nameservers" key used to contain
an array of binary addresses. If we change the key to contain
something else, there can be problems when the NM and the
NM-dispatcher versions mismatch (right after an upgrade or a
downgrade).

To avoid such problem, still send the old key in the old format, and
introduce a new key for the new format. The new format carries the
name servers as a string list, and can encode encrypted DNS servers.
---
 src/core/nm-dispatcher.c                | 14 +++++++++
 src/nm-dispatcher/nm-dispatcher-utils.c | 41 +++++++++++++++++++------
 2 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/src/core/nm-dispatcher.c b/src/core/nm-dispatcher.c
index 0abbca73a4a..16fb7e96b84 100644
--- a/src/core/nm-dispatcher.c
+++ b/src/core/nm-dispatcher.c
@@ -247,6 +247,20 @@ dump_ip_to_props(const NML3ConfigData *l3cd, int addr_family, GVariantBuilder *b
     }
     g_variant_builder_add(builder, "{sv}", "addresses", g_variant_builder_end(&int_builder));
 
+    /* We used to send name servers as a entry with key "nameservers" and binary
+     * value. That no longer works because name servers can be URIs. Send the
+     * value as an array of strings.
+     * To avoid problems when the NM and NM-dispatcher version don't match (right
+     * after an upgrade or downgrade), still send the old key in the old format,
+     * and introduce a new key for the new format. */
+    g_variant_builder_init(&int_builder, G_VARIANT_TYPE("as"));
+    strarr = nm_l3_config_data_get_nameservers(l3cd, addr_family, &n);
+    for (i = 0; i < n; i++)
+        g_variant_builder_add(&int_builder, "s", strarr[i]);
+    g_variant_builder_add(builder, "{sv}", "nameservers-full", g_variant_builder_end(&int_builder));
+
+    /* Old format for nameservers. This can be removed in the future when it's
+     * expected that both NM and NM-dispatcher support the new format.*/
     if (IS_IPv4)
         g_variant_builder_init(&int_builder, G_VARIANT_TYPE("au"));
     else
diff --git a/src/nm-dispatcher/nm-dispatcher-utils.c b/src/nm-dispatcher/nm-dispatcher-utils.c
index 6659936f48b..030506e944f 100644
--- a/src/nm-dispatcher/nm-dispatcher-utils.c
+++ b/src/nm-dispatcher/nm-dispatcher-utils.c
@@ -264,22 +264,43 @@ construct_ip_items(GPtrArray *items, int addr_family, GVariant *ip_config, const
         g_variant_unref(val);
     }
 
-    val = g_variant_lookup_value(ip_config,
-                                 "nameservers",
-                                 addr_family == AF_INET ? G_VARIANT_TYPE("au")
-                                                        : G_VARIANT_TYPE("aay"));
+    /* For name servers, prefer the new key and fall back to the old one. */
+    val = g_variant_lookup_value(ip_config, "nameservers-full", G_VARIANT_TYPE("as"));
     if (val) {
-        gs_strfreev char **v = NULL;
+        nm_auto_unref_ptrarray GPtrArray *arr = NULL;
+        GVariantIter                      iter;
+        const char                       *str;
+
+        arr = g_ptr_array_new_full(g_variant_n_children(val) + 1, NULL);
+        g_variant_iter_init(&iter, val);
+        while (g_variant_iter_next(&iter, "&s", &str)) {
+            g_ptr_array_add(arr, (gpointer) str);
+        }
+        g_ptr_array_add(arr, NULL);
 
-        if (addr_family == AF_INET)
-            v = nm_utils_ip4_dns_from_variant(val);
-        else
-            v = nm_utils_ip6_dns_from_variant(val);
         _items_add_strv(items,
                         prefix,
                         addr_family == AF_INET ? "IP4_NAMESERVERS" : "IP6_NAMESERVERS",
-                        NM_CAST_STRV_CC(v));
+                        (const char *const *) arr->pdata);
         g_variant_unref(val);
+    } else {
+        val = g_variant_lookup_value(ip_config,
+                                     "nameservers",
+                                     addr_family == AF_INET ? G_VARIANT_TYPE("au")
+                                                            : G_VARIANT_TYPE("aay"));
+        if (val) {
+            gs_strfreev char **v = NULL;
+
+            if (addr_family == AF_INET)
+                v = nm_utils_ip4_dns_from_variant(val);
+            else
+                v = nm_utils_ip6_dns_from_variant(val);
+            _items_add_strv(items,
+                            prefix,
+                            addr_family == AF_INET ? "IP4_NAMESERVERS" : "IP6_NAMESERVERS",
+                            NM_CAST_STRV_CC(v));
+            g_variant_unref(val);
+        }
     }
 
     val = g_variant_lookup_value(ip_config, "domains", G_VARIANT_TYPE_STRING_ARRAY);
-- 
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