libnm: valide IPv4 ECMP routes in NMIPRoute as unicast routes

Kernel does not allow ECMP routes for route types other than unicast.
Reject that in NetworkManager settings too.

Fixes: 3cd02b6ed6e7 ('libnm,platform: fix range for "weight" property of next hops for routes')

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1507

1 files changed, 19 insertions, 4 deletions

diff --git a/src/libnm-core-impl/nm-setting-ip-config.c b/src/libnm-core-impl/nm-setting-ip-config.c
index bea0ee7f11..3a31848e84 100644
--- a/src/libnm-core-impl/nm-setting-ip-config.c
+++ b/src/libnm-core-impl/nm-setting-ip-config.c
@@ -1303,8 +1303,9 @@ nm_ip_route_get_variant_attribute_spec(void)
 }
 
 typedef struct {
-    int type;
-    int scope;
+    int    type;
+    int    scope;
+    gint16 weight;
 } IPRouteAttrParseData;
 
 static gboolean
@@ -1440,6 +1441,8 @@ _ip_route_attribute_validate(const char           *name,
                                 _("route weight cannot be larger than 256"));
             return FALSE;
         }
+        if (parse_data)
+            parse_data->weight = (guint16) u32;
         break;
     case '\0':
         break;
@@ -1490,8 +1493,9 @@ _nm_ip_route_attribute_validate_all(const NMIPRoute *route, GError **error)
     guint                      attrs_len;
     guint                      i;
     IPRouteAttrParseData       parse_data = {
-              .type  = RTN_UNICAST,
-              .scope = -1,
+              .type   = RTN_UNICAST,
+              .scope  = -1,
+              .weight = 0,
     };
 
     g_return_val_if_fail(route, FALSE);
@@ -1540,6 +1544,17 @@ _nm_ip_route_attribute_validate_all(const NMIPRoute *route, GError **error)
         break;
     }
 
+    if (parse_data.weight > 0) {
+        if (parse_data.type != RTN_UNICAST) {
+            g_set_error(error,
+                        NM_CONNECTION_ERROR,
+                        NM_CONNECTION_ERROR_INVALID_PROPERTY,
+                        _("a %s route cannot have a ECMP multi-hop \"weight\""),
+                        nm_net_aux_rtnl_rtntype_n2a(parse_data.type));
+            return FALSE;
+        }
+    }
+
     return TRUE;
 }