From: Michael Bommarito Date: Wed, 17 Jun 2026 21:57:08 +0000 (-0400) Subject: net/sched: act_ct: fix nf_connlabels leak on two error paths X-Git-Tag: v7.2-rc1~29^2~72 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=16e088016f38cf728a0de709c3335cc5a3850476;p=thirdparty%2Flinux.git 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 Acked-by: Jamal Hadi Salim Link: https://patch.msgid.link/20260617215708.1115818-1-michael.bommarito@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index d47a82f9ac6ca..be535a261fa04 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -1296,7 +1296,8 @@ static int tcf_ct_fill_params(struct net *net, if (tb[TCA_CT_ZONE]) { if (!IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES)) { NL_SET_ERR_MSG_MOD(extack, "Conntrack zones isn't enabled."); - return -EOPNOTSUPP; + err = -EOPNOTSUPP; + goto err; } tcf_ct_set_key_val(tb, @@ -1309,7 +1310,8 @@ static int tcf_ct_fill_params(struct net *net, tmpl = nf_ct_tmpl_alloc(net, &zone, GFP_KERNEL); if (!tmpl) { NL_SET_ERR_MSG_MOD(extack, "Failed to allocate conntrack template"); - return -ENOMEM; + err = -ENOMEM; + goto err; } p->tmpl = tmpl; if (tb[TCA_CT_HELPER_NAME]) {