nspawn: enable all controllers we can for the "payload" subcgroup we create

In the unified hierarchy delegating controller access is safe, hence
make sure to enable all controllers for the "payload" subcgroup if we
create it, so that the container will have all controllers enabled the
nspawn service itself has.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index a56960506c..1c64c3e771 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -4737,6 +4737,7 @@ static int create_subcgroup(pid_t pid) {
         _cleanup_free_ char *cgroup = NULL;
         const char *child;
         int unified, r;
+        CGroupMask supported;
 
         /* In the unified hierarchy inner nodes may only only contain
          * subgroups, but not processes. Hence, if we running in the
@@ -4756,6 +4757,10 @@ static int create_subcgroup(pid_t pid) {
         if (unified == 0)
                 return 0;
 
+        r = cg_mask_supported(&supported);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine supported controllers: %m");
+
         r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &cgroup);
         if (r < 0)
                 return log_error_errno(r, "Failed to get our control group: %m");
@@ -4770,6 +4775,8 @@ static int create_subcgroup(pid_t pid) {
         if (r < 0)
                 return log_error_errno(r, "Failed to create %s subcgroup: %m", child);
 
+        /* Try to enable as many controllers as possible for the new payload. */
+        (void) cg_enable_everywhere(supported, supported, cgroup);
         return 0;
 }