net/sched: act_ct: fix nf_connlabels leak on two error paths

net/sched: act_ct: fix nf_connlabels leak on two error paths

tcf_ct_fill_params() calls nf_connlabels_get() (setting put_labels) when
TCA_CT_LABELS is present, but two later error sites use a bare return
instead of "goto err", skipping the err: nf_connlabels_put() cleanup.
They also precede the "p->put_labels = put_labels" assignment, so the
tcf_ct_params_free() fallback does not release the count either. Each
failed RTM_NEWACTION on these paths leaks one nf_connlabels reference:
net->ct.labels_used is incremented and never released. The action is
reachable with CAP_NET_ADMIN over the netns, i.e. from an unprivileged
user namespace on default-userns kernels.

Impact: an unprivileged user with CAP_NET_ADMIN over a network namespace
(e.g. via user namespaces) leaks one nf_connlabels reference per failed
RTM_NEWACTION on the two error paths; net->ct.labels_used is never
released.

The err: label is safe to reach from both sites: p->tmpl is still NULL
there (kzalloc'd, not yet assigned) and nf_ct_put(NULL) is a no-op, so
no inline release is needed.

Fixes: 70f06c115bcc ("sched: act_ct: switch to per-action label counting")
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20260617215708.1115818-1-michael.bommarito@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>