bus: raise fd limits before dropping privs

Startup ordering was changed in #92832 to ensure that SELinux audit
messages could be sent. As a side effect, the raising of file descriptor
limits was moved to after the dropping of root privileges, resulting in
the limit change always failing.

Move the raise_file_descriptor_limit() call to ensure that it is called
before dropping root privileges.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=105165
Bug-RedHat: https://bugzilla.redhat.com/show_bug.cgi?id=1529044
[smcv: Call raise_file_descriptor_limit() even if !context->user]
Reviewed-by: Simon McVittie <smcv@collabora.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/bus/bus.c b/bus/bus.c
index a6f8db475..abb2ea2f8 100644
--- a/bus/bus.c
+++ b/bus/bus.c
@@ -738,8 +738,6 @@ process_config_postinit (BusContext      *context,
   DBusHashTable *service_context_table;
   DBusList *watched_dirs = NULL;
 
-  raise_file_descriptor_limit (context);
-
   service_context_table = bus_config_parser_steal_service_context_table (parser);
   if (!bus_registry_set_service_context_table (context->registry,
 					       service_context_table))
@@ -971,6 +969,11 @@ bus_context_new (const DBusString *config_file,
       !_dbus_pipe_is_stdout_or_stderr (print_pid_pipe))
     _dbus_pipe_close (print_pid_pipe, NULL);
 
+  /* Raise the file descriptor limits before dropping the privileges
+   * required to do so.
+   */
+  raise_file_descriptor_limit (context);
+
   /* Here we change our credentials if required,
    * as soon as we've set up our sockets and pidfile.
    * This must be done before initializing LSMs, so that the netlink